Note: Descriptions are shown in the official language in which they were submitted.
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GRIPPER ARM AND METHOD OF OP~RA~ION
BACKGROUND OF THE INVENTION
Thls invention pQr~ains to gripper arm
structures, and particularly to grlpper arm sultable
S for use with insertion machine and the like.
Gripper arms have long been used with
insertion machines ox the type deplcted in U.S. Patent
2,325,455 to A. H. William3 which is commonly assiqned
herewith ~Q~. Prior
art gripper arms typlcally each have flxed and movable
jaw members. The fixed jaw member is usually integral
with the gr;pper arm while the movable jaw is
selectively operated so that articles, ah a
documents or inverts, can be engaged between and
released from the two jaws.
Prior art gripper arms have traditionally
been mounted on two elongated shafts which extend above
and along an insert track. The firs or upper shaft,
which osclllates once per machine cycle, has an upper
portion of the gripper arm keyed thereto so that the
gripper arm osclllates toward and away from a
corresponding lnsertion supply station in timed
relationship with the other operations occuring at the
station. The second shaft also oscillates once during
each machine cycle to actuate the movable jaw member
into and out of engagement with the fixed jaw membec in
timed relationship with the oscillation of the gripper
I,
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arm about the first shaft and with the rest of the
machine. A cam keyed to the second 6haft act upon a
connecting rod which in turn move the movable jaw
member away from the ixed jaw member against the
action of a ten3ion spring. The jaws are held apart in
this manner until thy gripper arm it oscillated toward
the corresponding in~er~ion station whereat the movable
jaw i8 portioned above and the fixed jaw it po~ltloned
below an inaert. The second shaft then oscillates Jo
clo e the movable jaw against the fixed jaw to ngage
and grip the inert the first shafk thereupon swing
awry from the invert station, pulling the selected
insert therefrom in a direction toward the insert
track. Over the insert track the second shaft iB
osalllated to move the movable jaw member away from the
mixed jaw and thereby release the insert, permltting
the insert to fall onto the table of the insertion
transporting mechanism.
Although only one gripper arm atructure ha
been de~crlbed above, a plurality of such gripper arm
are provided with an insertion machine, each gripper
arm being positioned in relation to corresponding
invert statlons linearly arranged along an invert
track. The area above the inset track is rather dense
wlth mechanical parts including the two shaf tB which
run through each gripper aem, as well as the associated
cams and connecting rods for each gripper arm. It is a
cumbersome operation to remove or replace an individual
gripper arm since the arm must be removed from two
shafts, each of which run the entire length ox the
insert track. Moreover, dellcate mechanical
ad~u~tment~ are required or each gripper arm 50 that
thP movable jaw member associated therewith can be
opened properly by gradual cam action taking into
consideratlon the thickness ox the insert material in
the hopper of the corresponding insert station.
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Insertlon machine of the tylpe described
above can operate through a range of ~peed~O An
operator may at a lower end o the ope.rational speed
range "step" or "jog" the maahine through a machlne
S cycle at a very slow speed a l u~ful in the aase o
settlng up the machlne with new materi,al. At high
operational speeds the insertion machine may operate at
a rote in the neighborhood ox 10,000 cycle per hour.
In setting up an insertion maahine, the
operator mutt be cognizant ox the fact that each lnGert
must be released at a preclse location along the invert
track, usually wlthln 1/8 inch of a specified precise
location. The time delay associated with the actuation
of the movable jaw member thus becomes a factor in
determinlng where on the insert track the lnsert will
be released. It the delay time in actuating the
movably jaw member it constant regardless of the
operational speed of the m~chine~ siynlficant error can
occur in placement of the inert on the insert track.
For example, a delay ox 20 to 25 m~lllseconds in
actuating the movable jaw member when the insertion
machine it operating at 10,000 cycles per hour results
ln the gripper arm travelling approximately one inch..
Thus, a given magnitude of time delay in actuating the
movable jaw member in the jog mode or a low speed is
not suitable for higher operational speeds and can,
when the machine is operated at higher speeds r regult
in significant misplacement of the insert on the insert
track.
In view of the oregoing, it is an object of
the present invention to provide a gripper arm whereln
the magnitude of delay involved in actuating a movabla
jaw member ls related to the operational speed of the
insertion machlne in conjunction wlth which the gripper
arm is employed
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An advantage ox the present invention ifl the
provlsion of a gripper arm having a movable jaw member
capable o engaging articles regardless o the
thickness of the articles.
Another advantage ox the present invention is
the provlsion of a gripper axm which is easily
manufactured, in~talledt and removed for serviaeability
reason.
Yet another advantage of the present
l invention i5 the provision of a gripper arm which has
few moving part, low mass, few lubrication poln~, and
few point of frictlon and wear.
A further advantage of the present lnvention
is the provision of a gripper arm wherein the
coefflclent o friction between an insert and a jaw
member it increased, thereby increaslng the force
available to pull an insert from a hopper of a
corresponding insert station but wlth less strain on
the gripper arm.
Still another advantage of the present
invention it the provision of a gripper arm having a
movable jaw member which tightly grip inserts
regardless of insert thickness
Yet another advantage of the present
invention is the provision of a gripper arm which, when
installed in an insertion machine, facilitates easy
acces3 to and around an invert track s~f the insertion
machine .
SUMMARY
A gripper arm include3 jaw members between
which articles are engaged and from which engaged
articles are released in precise placement upon a
transport means. Actuating means preferably in the
form of solenoid means is used to selectively move a
3!i 5econd jaw member toward and away from a if jaw
member in connectlon with the engagement and release
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operations. In view of the act that the actuating
means mutt be activated for diferent lengths o time
when the gripper arm it operated at d1f~ering peed in
order to result in precise placement a,f an article upon
the transport means, the timing of the activation of
the actuating means 1R controlled to be dependent upon
the operating speed of a machine in conjunction with
which the gripper arm it used.
In the above regard, jaw actuator control
means includes first sensor means or determining a
machine cycle rate; second sensor means for determining
when during each machine cycle the actuating means
should be selectively enabled and disabled; and, meanR
fur determining a suitable machine cycle rate-dependent
delay interval between the determlnation made by the
econd sensor means and the actual selective enablement
and disablement of the iaW actuating means. In a
preferred embodiment, the delay determining means
comprise an up/down counter enabled to count up pulses
prom a clock1ng means and, when allowed to do so by the
second 3ensor means, to count down pulses geneeated ln
accordance with the second sensor mean.
In another embodiment a jaw member ha a
piece of high coefficient of friction material embedded
in a surface oriented to contact articles engaged
between the jaws,
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, features,
and advantages of the inven~lon we 11 be apparent f rom
the following more particular descript1On o the
5 preferred embodiment a illustrated in the
accompanying drawing in whlch reference character
refer to the same parts throughout the varlou~ view.
the drawing are not nece3~arily to scale, emphasis
instead belng placed upon illustrating the prlnciples
10 of the invention.
FIG. 1 is a d{ agrammatical view of portion
of an insertlon machine according to an embodiment of
the inventlon;
FIG. lA is a rear view of a gripper arm
according to an embodiment of the invention;
FIG. lB it a side view taken along the lone
O of the gr$pper arm of ~19. lA;
. FIG 2 l an exploded view of the gripper arm
of another emb~dlment o the invention;
FIG 3 is a cirault diagram showing actuator
control mean3 according to an embodiment of the
invention;
FIG. 4 is a graph showing various parameters
as functions of machine cycles when a machine is
operating at 4t500 cycles per hour;
FIG. 5 is a graph showing various parameter
a function of machine cycle3 when a machine 1
operating at 10~000 cycles per hour;
FIGS. 6A and 6B are rear and side vlews,
respectively, of a Hall Effect device according to an
embodlment of the invention;
IGS. 7A and 7B are front and side views
respectively, of magnetic mean according to an
embodiment of the inventlon;
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FIG. 8 is an illustrative b1ock diagram of
mistake cletector fc)r a plurality of griLpper arm
according to an embodiment of the inventiorl;
FIG. 8A is a schematic dlagram depicting
5 electrical circuitry included in the mistake detector
of Fig. 8;
F IG . 9 i s a g r aph how i ng ou tpu t vol tag e f rom
a Hall Efe~t ~en~or as a junction of insert thickness
according to an embodiment of the invention
FIG. 10 it a schema~cic diagram depicting the
relationship of jaw members and magnetic means
relative to a p1vot point;
FIG. 11 is a detailed view of a portion of
the gripper arm of Fig. lA;
FIG. 12A is a detailed rear view o a portlon
of the gripper arm of Fog. lA;
FIG. 12B is a detailed view of a portion of
the gripper arm of Fig. 12A cut along the line ED";
FIG. 13 it a wide sectional vlew showing
first sensor means and second sensor means mounted in
relation~h~p to main drive hat means;
FIG, 14 it an end view of an actuator timing
disc included in a second tensor means; and,
FIG. 15 it a graph showing solenoid force
requirements and spring force requirements as functions
both of solenoid and upper jaw member positions
according to an embodiment ox the invention.
DETAILED DESCRIPTION OF THE DR~INGS
Referring to Fig. 1, there is shown an
insertion machine 10 which collects a plurality of
inert into a pile and transport what pile to an
inverting station IS; conveya an open envelope to
inserting station IS; and, then insert3 the pile of
lnserts into the envelope. Turing steps unillustrated
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~6--
in Fig. 1 the insertion machine 10 later seal the
envelope and pro~e~e~ the envelope or malling. It
wlll be appreclated that the operation ox machine 10 ls
timed in accordance with a machlne cycle. In this
respect, an indlvidual envelope require several
machine cycles to be processed. With the exception of
a few initlal or start-up machlne cycle, a pile of
inserts it inverted into an awalting corresponding
envelope at the end ox each machine cy¢le.
In order for insertlon machlne 10 to collect
a pile of insert at inverting 3tation IS, there ar,e
provided therein a plurality of insert stack stations
or hoppers Sly S2, and S3 and a plurallty of
corresponding gripper arms 161, 162, and 163 each
mounted to a shaft 17 which extends over an insert
raceway 18. Insert statlon Sl, gripper arm 161, and
shaft 17 serve to wlthdraw one insert from the tack ox
insert and drop that in~er~ onto'raceway 18r More
particularly, invert station Sl holds a tack of
inserts Il on a manner whereby the bottommost invert i8
separable from the rest of the tack Gripper arm 161
is connected to shaft 17 which oscillates once during a
portion of each machine cycle in order to rotate arm
161 toward and away from the tack of inserts While
rotating toward the stack5 the jaws of gripper arm 16
are opened to allow the art to engage the bottQmmost
insert When the shaft 17 stops moving arm 161 toward
the stack, the jaws are closed to engage the bot0mmo3t
insert. Shaft 17 then rotates gripper arm 161 away
3G rom the tack, thereby withdrawing the invert from the
bottom of the stack. Gripper arm 161 then opens its
jaws to release the insert which fall3 onto invert
raceway 18. Thus, insert station 51; gripper arm 161,
and shaft 17 cooperate to withdraw one lnsert from the
tack and drop that insert onto raceway 18.
33
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Insert raceway 18 include a pIurallty of
palrs ox pusher pins P which are mounted on a palr of
chalns snot shown) whlch are perlodlcally drlven by
machine 10. The chains are drlven once during a
portion of each machine cycle and move the pusher pins
P to the next lnser~ stat;on. Ater the ju~t-described
dropping of an insert from station Sl onto raceway 18,
for example, pin P push the insert to the vicinity of
the lnsert talon S2 and top.
In view of the foregoing, it wlll be teen
that invert ~tation~Sl, gripper arm 161, shalt 17, and
raceway 18 cooperate to withdraw one insert from the
stack and convey that in ert to station S2. It will be
appreciated that for the embodiment 3hown one insert
from station Sl is conveyed to statlon S2 each machine
cycle.
Insert station S2, grlpper arm 162, and shaft
17 cooperate in a similar manner insert ~tatiun Sl,
gripper arm 161, and shaft 17 and serve to withdraw one
2~ invert from the stack o inserts at talon S2 and drop
that insert onto raceway 18~ More particularly, insert
stack station So holds a stack of inserts I2 in
manner whereby the bottommost insert is separable from
the rest of the ~tackO Gripper arm 162, which is also
connected to oscillating shaft 17, rotates toward the
bottommo~ insert; grab that insert; rotates away from
the stack; and, then releases the lnsert. This insert
fall ontb insert raceway 18 which already contains an
insert Il. Pusher pins P of raceway 18 advance this
pile to the next insert station. thus, during another
machine cycle, invert station S2, gripper arm 162,
shaft 17, and raceway l cooperate to add an insert I2
to insert Il and convey the pile to station S3.
Invert station S3, gripper arm 163, and shaft
17 cooperate in a similar manner as insert station 51
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and S2, grlpper arm 16~ and 162, and shaft 17 and
verve to wlthdraw one insert from the tack o 1nserts
at stat10n S3 and drop thaw inert onto raceway l
Invert stack station S3 separates the bottommo~t invert
rom the rest of a tack of inverts I3. Gripper arm
163 rotate Howard the bottommost inse!rt; grabs that
insert; rotate3 away from the stacks and, releases the
lnsert onto inserts Il and ~2 on raceway lB. This
thereby completes the pile of inserts. ~acsway 18 then
conveys the completed pile Jo inserting statlon IS.
Thus, during a thLrd machine cycle inert 3tation S3,
gripper arms 163, shaft 17, and raceway 18 cooperate to
add an invert I3 to a pile of insert and convey 'che
pile to inserting station IS.
In view ox the foregoing, it will be seen
that insert stack stations Sl, S2, and S3, respective
gripper arm 161, 162, and 163, and insert raceway lB
cooperate to collect a pile of hefts and convey that
pile to nserting station IS in three machine cycle .
A mentioned above, insertion machine 10
convey an open envelope to inverting station IS. To
this end there are provided an envelope tack ~atlon
ES; an envelope flap opening ~tatlon ~0; a flap hold
down bar 19; and, an envelope raceway 21~ Envelope
stack statlon ES holds a stack of envelopes; separates
the bottommo~t envelope from the rest of the stack;
and, feeds the envelope to a clamp C in envelope
raceway 21. Envelope raceway 21 includes clamp C which
is mounted on a chain snot shown) which is periodically
drlven by machine 10. The chain iB driven once during
a portion oE each machine cycle and moves the envelope
to an enYelope flap opening station EO. At station EO,
a sucker cup (not shown) rotates toward the closed flap
of an envelope, applies a vacuum to the flap and
rotates away f rom the envelope in order to open the
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_9_
flap ox the envelope. The raceway 21 then moves the
envelope to the inserting sta~1on IS while the flap of
the envelope ls held down by bar 190
When an envelope and a pile o inserts are at
inserting station IS, insertion machine 10 inserts the
pile of 1nserts into the opened envelope. .To this end,
there are provided in machlne 10, a pusher arm PA and
a vacuum bar VB. The vacuum bar VB lifts up the back
(top) wide of the envelope end shaft 17 rotates and
thereby moves pusher arm PA toward tha opened
envelope As a result, the pile of inverts will be
pushed ho the envelope. Thua, pusher arm PA and
vacuum bar VB cooperate to invert a pile ox inverts
into an opened envelope at inserting station IS,
although Fig. 1 shows an insertion machine
with three insert stack stations Sl, S2, and S3, it
should ye understood that the number of lnsert stack
stations 13 not critical Jo the prevent 1nven~ion and
what In other embodiments fewer or more such invert
station are employed along a suitable raceway.
A discussed hereinbefore, during the
operation ox machine 10 it i8 highly d~irable to
provide an indication when one of the gripper arms
grips too few or too many inserts. Insertion machine
10 includes an improved double/miss detector which is
relatively easy to calibrate and adjust and which is
described in detail below.
In additionJ it should be appreciated that it
is desirable to provide a reliable gripper armO
Insertion machlne 10 includes a reliable gripper arm
which will now be described.
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GRIPPER ARM MECHANICAL STRUCTURE
Each grlpper arm 16 according to an
embodiment of the invention includes a houslng 20;
securing means 22 for securiny the grlpper arm to
osclllating drlve means such as heft 17~ A fist
article-contacting or jaw member 24; a second article-
contacting or jaw member 26S jaw actuation means, suGh
as solenoLd actuation mean 28; and, linkage means
30. Flgs. lA and lB (as well as Figs. 11, 12A, end
12~) show a gripper arm ac¢ord~ng to one embodiment of
the inventivn while Fig. 2 shows a gripper arm of a
second embodiment which is generally similar Jo the
embodiment of Figs. l but which includes different
structure for ~t3 linkage means. Structural element
common to the embodiment of Fig. lA and lB and Fig 2
ar¢ assigned the tame reference numeral3 for
description purpose3 hereinafter.'
Gripper arm housing 20 has a distal end 32
and a proxlmal end 34. The means 22 for securing the
gripper arm to the oscillating drive shaft 17 include
(l) a aemi-cylindrlcal recess 3~ at the top of the
proximal end 34 of the gripper arm housing 20, and (2)
a clamp member 3B. The recess surface 36 is contlguou~
with flanges 40 on either s$de o the recess 36~ The
flanges are generally parallel to the major cylindrical
axis of the recess 36. The clamp member 38 mates with
the proxlmal end 34 of the housing 20. The clamp 38 it
formed with comparable flanges 42 which mate with the
flanges 40 of housing 20. The clamp 38 has a
cylindrical sector portion 44 which forms a semi-
cylindrical recess 46. Each ox the 1anges 40 and 42
have two threaded apertures thereln appropriately
aligned to receive threaded fasteners 48. In this
respect, flanges 40 have aperture 50 and flange 42
~3~ 3
have aperture3 52. The fa~ener~ 4~ secure clamp 38 to
the proximal end 34 of the housing 20 so that the
gripper arm is clamped onto the oscillating drive shaft
17. Each threaded fastener 48 extends through the
aligned aperture 50,52 and the housing flange 40 and
the clamp flange 4~, respectlvely.
The gripper arm housing 20 comprises opposing
side panels 54 which extend the helght 5f the gripper
arm. The two side panel 54 define a space
therebetween. At the proximal end 34 of the gripper
arm housing 20 the wide panels 54 are parallel and
separated by a distance A as shown ln Fig. lA. it the
mid-section o the gripper arm hou~i~g the slde panels
54 begin to converge to one another but separate beore
dolng so and continue in parallel manner to the do stal
end 34 o the housing 20. A thy distal end ox the
housing the 3ide panel 54 are spaced apart at a
dl~tanc:e B whlch i le3~3 than distance A a shown in
Fig . lay, .
In the region where the wide panel 54 are
separated by the distance A, a fronk panel 56 it
integral with the wide panels 54. In this region where
the wide panel 54 are separated by the dis'cance A,
each side panel 54 has at its back a perpendicularly
extending flange 58. Each flange 58 has two threaded
aperture 60 therethrough, as well a3 a vertically
extending channel 6~ at the intersection of the plane
which includes the lnterior surface of the hou~ing-side
panel 54 and the plane which includes the flange 58.
The gripper arm housing 20 also includes a
backplate 64 which has a back member 66 and a base
member 68 perpendlcular thereto The back member 66
has four aperture 70. Two of the apertures 70 are on
each side of the back member 66, each aperture 70 being
aligned with apertures 60 on the ~id0 panel flanges 58
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when the back member is a sembled to housing 20.
Threaded fastener 72 extend through the aperture 70
of backplate 64 and through the aperture 60 o the side
panel flange 58 to aecurs the backplate 64 to the
geipper arm housing 20. The base member 68 ox the
backplate 64 is adapted for placement between the side
panels 54 in an area where the 3ide panels begin Jo
¢onverge~
As described above, the side panels 54, front
plate 56, back member surface 56, and backplate base
member 58 generally refine a hollow volume 74. Volume
74 ls not totally confined, however, inasmuch as the
base member 68 of the backplate 64 ha an aperture 76
thereon and the height of the back member 66 of
backplate 64 $~ such as to leave an essentially
rectangular gap 78 above the backplate 64.
Volume 54 houses the jaw actuatiny meana
which, ln the illustrated embodlmént; it solenoid means
28. The solenoid mean 28 has an essentially
2~ cylindrical casing 80. Solenoid cawing 80 has a
mounting plate 82 secured thereto. In the embodlment
shown, the mounting plate 82 has protrusions 84 thereon
adapted to fit into the channel 62 of the side panel
flanges 58. As shown in Fig. 2, electrical leads 86
extend from the interior ox the solenoid casing 80 and
are included in a ribbon-type cable 907 Although not
shown a5 such ln Flg. lA, it should be underskood that
the ribbon cable 90 extends from the volume 74 out
through the rectangular gap 78 on the back of the
tripper arm and is connected Jo appropriate circuitry
including the type of circuit shown in Fig. 3, the
circuitry to which the ribbon cable 90 l connected
resides on a circuit board or the like situated
elsewhere on the particuiar machine in conjunctlon with
which the gripper arm of the invention operatesO
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Toe ~oleno~d mean 28 alto compr1se~ a
plunger means 92. Near it bate plunger mean 92 ha
an annular groove about which C-clamp rleta1ner 96
f lt~o the lower end o the plunger 92 'ha a slot 98
S therein through the diameter o the plunger 92. The
plunger 92 alto has an aperture 100 extending
therethrough along a diameter of the plunger 92 which
is transverse to the slot 98. The plunger aperture :L00
it adapted to receive a rollpin 102.
Turning now to the embodlment of Fig. 2, the
llnkage mean 30' comprises a biasing means and a
connecting rod 120. The biasing means includes a
cylindrically coiled inner spring or extension sprung
12?. having coils formed generally in planes
perpendicular to the major axis of the cylinder. The
~nnee ping 122 has flr~t and second ends formed in
~ing-llke fashion, the end ring being formed ln plane
ln which the axis of the cylinder lie (that iB, the
planes of the end rings are generally perpendlcular to
the planes of the coil included on inner spring
122~. Ring 124 at the upper end of the inner spring
122 is adapted to receive pin 102 therethrough when the
ring 124 it inserted into the slot 98 of the plunger
92. Ring 126 at the lower end of the inner spring 122
i8 adapted to receive a pln 128. Lower ring 126
receives pin 128 whey the lower ring 126 is inverted
into a tran~ver~e slot 130 formed in a irst end of end
cap 132. End cap 132 has an aperture 134 through the
diameter whereof which intersect the lo 130 ln
perpendicular ~a~hion in a manner similar to the slot
98 on apertures 100 ox the plunger 92.
End cap 132 has an annular shoulder 136 near
its mid3ection BO that an outer pring 13~ can be
confined between the shoulder 136 and the base member
68 of the backplate 64. Thus, the outer ~prlng 138 ls
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ox greater diameter hart toe inner spring 122 and fits ln
concentric Eashion over the inner sprlng 122. the
outer spring 138, according to one mode of the
lnven~ion, preloads the inner expansion spring 122 by
S stretching spring 122 a desired distance 50 that spring
122 cause jaw 26 to exert a force of a desired
magnitude on insets engaged between jaws 24 and 26.
A further seen in Fig. 2, the lower end ox
the end cap 13~ receives a threaded top 1~0 of the
connecting rod 120. The connecting rod 120 extends
between planes ln which the do panel 54 are lncluded
downwardly toward the distal end 32 o the housing
20. The rod crooks outwardly to the side at polnt 142
as it extends downwardlyl and when bend inwardly to
have a por~lon 144 in horizontal orientation at the
lowest extent of its travel. the lower end 144 of the
rod is adapted to receive a lock member, such as
C-clamp retainer 146.
The dial end 32 of the gripper arm housing
30 has, in the Fog. 2 embodiment shown, a first jaw
member 24 which i6 formed lntegral with the housing 20
a a lower jaw member. A rectangular recess 160 ig
Çormed in a surface of the jaw 24 which is oriented to
contact an article to be engaged by the gripper arm.
rrhe recess 160 is adapted to receive a piece of high
coeficient of friction material, such as a piece of
urethane 162.
The second jaw member 26 as shown in Fig. 2
comprises a block 170 insertable in a space defined by
the separated lower ends of the side panel 54. The
block 170 has a protruding curved member 172 extendlng
therefrom, the underneath surface of which contacts
article to be engaged by the grlpper arm. Block 170
also has two aperture 174 and 1~6 extending
therethrough. The aperture 174 l adapted to receive a
~%33~
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pivot pln 17B so that the second jaw member 26 can
pivot about the pln 17~. rrhe 0econd aperture 176 it
adapted to receive the horizontally extending lower end
portion 144 of the connectins rod 122.
The pivot pin 17~ i5 received not only
through aperture 174 in the jaw member 26, but also
through aligned apertures 180 ln the distal end of the
slde panels 54. Thus, when the seaond jaw member 26 is
lnserted in the space between the side panel 5~ near
lQ the dl~tal end 3~ of the gripper arm houzing 20, the
aperture 174 and 180 are aligned BO that the pivot pln
178 can freely fit therethrough. The plvot pin 178 it
retained in position by a set screw 181 so that the
plot pin 178 rotates in bearing-like end cap5 182.
lS The embodiment of Figs. lA and lB differs
tightly from the embodiment of Flg. 2, ln the
configuratlon of the partlcular linkage means
utilizedO Whlle the embodiment of Figs. lA and lBj
like that o Fig. 2, ha an inner spring 122, the inner
spring 122 of the embodlment of Fig. lA and lB i5
positioned ln a cylindrical spacer or sousing 202. As
¦ in the Fig. 2 embodlment, the upper ring 124 of the
l inner sprlng 122 it secured by plunger pin 102 to the
I solenoid plunger ~2. The top of the cylindrical
251 housing 202 abuts the lower end of the plunger 92.
! The lower end of cylindrical houslng 202
abuts a retaining rung 203. The re~alning ring 203 is
carrled ln an annular rece 5 on a clevis-type end cap
204. The pin 128 extends radially through the end cap
20~ in a manner understood from the description of the
end cap 132 of Flg. 2. End cap 204 axially receive a
; pin 205 which has an upper exterlor portion thereof
! threaded or engagement in an axial aperture of end cap
1 204. An upper end o a cable 206 is connected to the
35 1 lower end of pin 205. Cable 206 extends rom the pin
'I
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205 to the distal end 32 of the grlpper jAW. At it
lower end the table 206 ha a ball 208 fixedly attached
thereto.
Located in the cylindrical housing 202 in the
manner described above, the inner spring 12~ of Flgs.
lA and lB i3 held so that it it generally extended
about D.25 inches beyond i~B length a rest. The
spring 122 is thua preloaded to h~Ye a desired sprung
force
For the embodiment of Fig. lA and lB and 11,
the upper jaw member 26 comprlses a block member 210
and a curved protrusion 212. The underside of the
protrusion l used to contact articles engaged by the
gripper arm. The block member 210 ha a narrow slit
214 at the back thereof through which the lower portion
ox cable 20~ extends. At the bate of the slit 214 it
an essentially square chamber ~15. Chamber 215 hove
ball 2n80 When cable 206 pulled upwardly the ball
208 thereon, having a greater d~ama~er than the wLdth
of the slit 214, bears agalnst the top interlor surace
of the chamber 215, causing the upper jaw member 26 to
pivot 50 that the upper jaw member 26 approaches the
lower jaw member 24 Jo that the jaw esqent~ally
closes.
The block member 210 of second jaw 26 also
has three apertures 216, 218, and 220 extending
therethrough. The central aperture aperture 218)
accommodates a pivot pin 222 about which the jaw member
26 pivot.
The embodlment of Fig. lA and lB and 11
further comprises means or biasing the jaw member in
an open posi~icnO The biasing means includes torsion
spring 230 (seen in Figs. 12A and 12B). An
intermediate portion of the torsion spring 230 has a
helical shape whlch is concentric wlth and its over on
~;23~3
-17-
exposed end of plvot pln 222, the end olE pln 222
protruding beyond a side panel (the left ode panel a
seen on Fog. 12~) of the gripper arm. A it exposed,
protruding end the pivot pin ~22 has a head 232 formed
thereonO A disc 234 is secured on the plvot pin 222
just inside its head 232. The helical portlon of the
torsion spring extend between the disc 234 and the
left side panel oP the gripper arm, A one ox it end
the torsion spring 230 departs from it8 helical
configuration and a~Rumes a linear shape as it extencls
upwardly to a retaining pin 236 against a side of which
it bear (Lee jig. 12~). At it other end the torslon
spring 230 extend through a square notch 238 formed on
the circumference of the disc 234. The portion of the
torsion spring 230 that extend through the disc 234
bears against a corner 2~0 of the notch 238. Spring
230 bears against corner 240 to exert a biasing force
on the disc 234 and the pivot pin 222 whereby the upper
jaw member 26 i8 normally held open in the absence ox
application of tension to the cable 206. When cable
206 and ball 208 thereon are urged upwardly, however,
ball 208 bears against the upper interior surface of
the chamber 215 and exert a force on block 210 which
overcome3 the biasing force of the torsion spring 230
so that block 210 pivots about pin 22~, thus causing
jaw 26 to clove.
GRIPPE A~M-ASSOCIATED
OPTO/ELECTRICAL STRUCTURE
Fig. 3 shows circuitry utilized in connection
with the gripper jaw actuating control mean3 according
to an embodiment of the invention. An encoder disc 260
and an actuator timlng disc 262 are mounted to rotat2
on a main drive shaft 263 of a machlne, such a an
~3~ 3
-18 -
lnsertlon machinel in connection w1th which the gripper
arm 16 of the inventiorl operates. The maln drive ~haf t
rotate once per machine cycle and ha various tlming
and drive means rigidly coupled thereto for power
tran~mi3slon, quch a the aforementioned 03cillating
driva mean 17, or example. The encoder disc 260 is a
64-tooth disc. The actuator timlng disc 262 ha us
clrcumference configured to allow the passage o light
(in a direction perpendicular to the plane ox the disc)
about a disc central angle 266 corresponding to
portion3 of a machine cycle during which the actuation
means of the gripper arm it to be actuated 50 that the
second jaw it either in contacting relation with the
~ir~t jaw or ha an article gripped between the first
jaw and the second jaw.
Fig. 3 shows an encoder disc sensor 300
including the above-mentioned encoder disc 260
positioned to cause pa~age ox light from an LED 302 to
be periodically incldent on circumferential teeth of
the encoder dl c. If the light from TED 302 impinge
on a tooth of the dlsc, then the light it not
transmitted to receiver 304. If 2 circumferentlal
space between the teeth on the encoder dlsc it allgned
with a beam of light from LED 302, then the receiver
304 detect the light. An actuator timing disc sensor
306 also includes the above-mentioned actuator timing
di c 262 with an ED 308 and a photoreceiver 310
similarly arranged about the ackuator timing dlsc.
The opto-interrupt receiver 304 it connected
to two inverting drivers 312,314 in serles with one
another. The output ox thé inverting driver 314 it
connected to both input terminals vf a N~ND 316, the
output ox which it connected to both i nput termlnals of
a second NAND 318. The output of NAND 318 ig connected
to two other NAND~ ~NAND~ 320 and 322).
I' i
~3~3
--19
The clrculk of Fig. 3 also includes a clock
or timer 324 having its clock output pin spin 3)
connected to a ~ir~t input of a NAND 326. The NAND3
320 and 326 have their output terminals ¢onnected to
respective input terminals of a fal~e-actuated 0~ gate
328. The output terminal ox OR gate 328 is connected
to a clock input pin (pin 15) ox a delay determination
means, such ag a pre~ettable up/down binary counter
33~.
.~ Up/down counter 330 ha its reset input pin
connected to an output terminal and an EON gate 332.
One input of the EOR 332 is connected to ~12 volts; the
other input terminal it connected to the output of RAND
3~2~
i5 The up/down directlon pin spin 10) o the
counter 330 i3 connected to the Q output of a "Do Ellp-
flop 3340 The set and reqet input pin3 of the flip-
slop 334 are grounded. The "D" or data input pin of
the fllp-~lop 334 is connected to a compare signal in
the manner hereinafter described The clock input pln
spin 11) of the flip-10p 334 i8 connected to the
output of NAND 318.
The data input pin (pins 4, 12, 13d end 3)
and pin 5 of counter 330 are grounded. Output pins 6
and 14 of the counter 330 are connected to respective
input terminal of a NAND 336. The output terminal of
NAND 336 Lo connected to the reset terminal (pin 4) of
k timer 324~
The carry~out terminal (pin 7~ of counter 330
is connected to a first input terminal ox a NAND 338.
The second input terminal of NAND 33B it connected to
an appropriate voltage eor setting initial condition
for machine start-up. The output of NAND 338 it
connected to a first input kerminal of an EOR 340, the
other input terminal of the EOR 340 being connected to
I? V
~L233~3
-20-
a ~l2 volt3~ The output ox the EOR 340 18 connected to
a clock lnput pin (pin 3) o a "DN flip-flop 342,
Flip-lop 342 ha its reset and jet ~erminal3
spins 4 and 6, respectively) connected to ground. Thy
"Do or data terminal it connected to thlo output of
inverting driver 344 and 346 which are connected in
series between the receiver 310 and the fllp-flop
3~2. The Q output terminal spin l) of the flip-flop
342 it connected both to the first input terminal of an
EOR gate 350 and to two inverting drivers 352 and 354
ln cries The other input termlnal of the Eon 35D Ls
connected through the in~ertlng driver 344 and 346 to
the re¢eiver 310 o the actuator timing do 306.
The output terminal of the EOR 350 is
connected to an inverting driver 356~ The outpu
termlnal of the inverting driver is in turn connected
both to the data input pin spin 9) of flip~flop 334 and
to the second input terminal of NAND 322.
The Q output terminal of slip flop 334 it
alto connected both to the second input terminal of
NAND 326 and to a f$rst input terminal o an EOR gate
358. the other input termlnal of toe EOR gate 358 it
connected Jo +12 volts. the output terminal of the EQR
gate 358 is connected to thy second lnput terminal of
NAND 3200
In the illustrated embodiment, NAN~s 316,
318, 320, 322, 326, 336, 338, and false-activated OR
328 are included in a single integrated circuit chip
such as a QUAD-2 Input NAND Schmitt Trigger. Counter
330 it a presettable up/down binary counter. EOR gate
332t 340, 350, and 358 are included in a quad Exclusive
OR gate. Flip-flop~ 334 and 342 are lncluded in a Dual
"D" Fl~p-Flop Chip. Clock 324 is a linear timer.
Inverter driver 312, 314, 344, 346, 352, 354, and 356
are included ln a 7-channel PMOS Input Driver.
~21
For the embodiment of Flg. 3, by way ox
example, re~3istance values are g1ven Jo the resistors
and capacitance values are given to the capacLtance~ aa
shown on l:he hollowing chart:
RES I STANCES
Rl = R2 - R3 = R4 = lK
:~5 5K variable)
~6 R7 8 ~8 - 1. 2R
R9 ye R10 lûOK
Rll R12'~ ~13 - R14 = 10
R15 = 470 Ohm
CAPACITANCES
Cl 0.1 F
C2 = 0.001 F
C3 1.0
C4 0~47 F
~5 - 0.01
MIgTAKE DETECTOR
A mentioned above, lnsertion machine 10
includes an improved double~mi~ mistake detector.
This double/miss detector indicates when owe of gripper
arms 161, 162, or 163 qrip too ew or too many
in~ertsO More particularly, a3 shown in Fig 8, there
is provided a double/miss detector for each ox the
gripper arms i.e., a detector 364/ 374, and 384 for
lndicating when gripper arms 161, 162, and 163,
respectively, grip the wrong number o inserts. Since
detectors 364, 374, and 384 are substantially imilar,
only detector 364 will be described in detail and it
will be understood that detectors 374 and 384 wlll
operate in a similar manner under simllar conditions.
~23~ L3
-22-
Detector 354 serves to detect when grlpper
jaw 161 ha gripped too few or too many inserts. To
this end, there are provided in deteatoL 364, a jaw
displacement tensing means 366 and a mi.stake 1ndicating
circuit 365. Jaw dlsp1acement sensing means 366 it
mounted on the gripper ~aw~ ox arm 161 a hereinafter
descrlbed and serve to generate an e1e!ctrica1 signal
propor~lonal to the relative d~sp1acem~nt between the
grlpper jaw. When a proper number of inserts aye
known to be gripped between the gripperljaw~, a witch
is closed and a Bet pu1se 1B provided to mistake
indicating circuit 365 which then serves to convert the
electrical signal proportional to jaw displacement to a
stored reference slgna1. ThiB stored reference signal
is u6ed by indicating circuit 365 during a preselected
time ox a machine cycle to determine if thy electrical
signal generated by ~en~ing device 366 is wlthin
predetermined 1imits.
It will be appreciated that the jaws of the
gripper arm are forced open prior to grabbing the
insert and the jaws are forced open in order to release
the in3ert~ Since Sensing means 366 continuously
generates an electrlcal signal proportional to jaw
displacement, it is desirable to indicate a mistake
condition only during the portion of the machine cycle
when the gripper jaws are holding the insert, i.e.,
when the inserts are being pulled from the tack. In
the present embodiment, a timing signa1 is applied to
indicating circuit 365 shortly after the gripper arm
30 has pulled the insert from the stack and circuit 365
indicates a mistake condition only during this enabling
signal. Thus, although sensing means 366 continuously
yenerates an electrical signal proportional to jaw
displacement indicating circuit 365 indicates a
-23-
mistake condition only when the jaws are displaced by
the inserts.
To the end that mistake indicating circuit
365 may swore a reference slgnal and indicate when a
proper number ox documents is not grlpped by the
gripper jaws, there are provided in indicator 365, a
signal generating means 367; a comparing means 368; a
storing means 369; a transmission gate 370; and, a
mistake ind1cator/alarm means 372. signal generating
10 jeans 367 l connected to ~en~ing means 366 and
generate three electrical signals which are
proportional to the signal generated by sensiny means
366. The first signal generated is proportional to the
signal generated by sensing means 366 and is applled to
a input of storing means 3690 The second signal
generated it a 1xed percentage greater than the flr~t
eignal and correspond to the lower llmit oÇ acceptable
jaw displacement. the thlrd 3ignal generated i5 a
fixed percentage less than the ir~t 3~gnal and
corresponds to the upper limit o acceptable jaw
displacement. Storing jeans 369 tore the first
electrical signal from generating mean 367 during the
detector set-up or calibration time and thereafter
applies that stored reference to comparing mean 368.
Comparing mean 368 compares the second and third
signals from generating means 367 with the stored
reference slgnal from storing means 369 and generate a
first electrical signal when the results ox the
comparison indicate that too few inserts have
been grabbed by the gripper jaw and a second electrical
signal when the results of the comparison indicate
that too many inserts have been grabbed by the
gripper jaw. The results o comparing means 368 are
applied to the input o a transmission gate 370 which
Q~
~33~3
--24--
provides a mistake indicatis:n only after the gripper
jaw pulls the invert from the tack.
MIST~E DETE:CT0~ SENS0~ STRUCTURE
Figs. 6A and 6B show a sensor means 400
5 which, as shown in Figs. lA and lB, is mounted near khe
distal end 32 of the gripper arm 16. The sensor means
400 it included in the jaw dlsplace~en~ sensing means
such as ~en~ing mean 366 of Fig 8. The sensor mean
40û include a housing block 402 havlng a rectangular
channel 404 wormed on its front surface. The
rectangular channel qO4 has only one edge 406 thereof
extending to an edge of the housing block 402~ rrwo
fastener 40B having their shats flush wlth the
channel 40~ extend through the housing block 402 to
secure the sen or means 400 to the gripper arm in the
location depicted in Fix. lA and lB.
The Yen~or mean ~00 further include3 a aover
plats 410 which as teen in the rear view of Fog. 6A has
rectangular dlmen~ion~ comparable to the front
rectangular dimensions of the houslng block 402. The
cover plate 410 i6 secured onto the housing block 402
by an epoxy adhesive material. A sensor element 412 ls
accommodated in the rectangular cavity defined by the
housing block 402 and the cover plate 410. Sensor
element 412 serves to sense the flux density of a .
generated field and generates an output signal
proportional thereto. In one embod1ment the sensor
element 412 comprises a current-carrylng electrical
conductor across which a voltage is generated when the
conductor it in a magnetic fîeld, the magnitude of the
generated voltage being proportional to the magnetic
field flux intensity. on example o this embod.~ment of
sensor element 412 is a Hall Effect sensor element.
! `J
-25-
cable 413 comprislng three leads 414, 416, and 41B
extends from the sensoe element 412 to the circult of
Fig. 8A as hereinafter described.
Figs. 7A and 7B show a magnetic means 420
which is included in the jaw displacement senslng mean
~uah as mean 366 and which cooperate with the senBor
means 400. The magnetic means 420 includes two rare
earth magnets 422 and 424, each being essentially disc
shaped. Each disc-shaped magnet 422,424 is mounted in
corresponding circular aperture formed in a disc-
shaped holder 426 having a dlameter at least greater
than the sum of the diameter of the magnets
A seen in Fig. 7A, magnet 422 has it North
pole exposed while magnet 424 ha lts South pole
exposed. The clrcumerences of the two disc-~haped
magnets come clo3e to touching on a line 428 which
connects their centers.
The magnet holder 426 it further mounted on a
mountlng bracket 430. Mounting bracket 430 is a thln
sheet of a re~llient metal such a Spring Temper
Bra. Bracket 430 it bent along a line 432 which
~epara~e an upper beacke~ portion from a lower bracket
portion. In its natural state (i.e., not installed in
the gripper arm 80 that no external mechanical forcez
are acting on the upper portion of the bracket 430),
the upper bracket portion bends away from the lower
bracket portion at an angle alpha which is
approx1mately 15 degrees. The upper bracket portion
has the magnet holder 426 mounted therein. The lower
bracket portion has three apertures extending
therethrough. A central aperture 434 i9 sized to
accommodate the pin 222 which functions as the pivot
point about which the second jaw member pivot with
respect to the first jaw member. The central aperture
434 is po~ltioned so that an imaginary line 436
3~3
--2~--
extending through the diameter ox aperture 434 and
con~truc~ed perpendicular to line ~28 intersect line
428 midway between the centers of magnet:s 422 and
424. The point of lntersection of the lmaginary line
436 and the llne 428 bisected thereby it; taken us the
center of the magnetic f ield and labeled as point X it
the drawing. Apertures 438 on either side of central
aperture 434 are adapted to receive fastener3 440
which, as seen in Fig. lA, secure the magnet means 420
and particularly mounting bracket 430 of the imaginary
line 436 and the lint 428 blsected whereby i8 taken as
the center of the magnetic field and labeled as point:
on the drawing Apertures 438 on either slde of
central aperture 434 are adapted to receive fastener
}S 440 which, as seen in Flg. lA, secure the magnet meanY
420 and particularly mounting bracket 430 thereof to
the second jaw means 26.
As shown in FigO lB, thé màgnetic means 420
i3 sandwiched between a gripper arm side panel on itB
one ~lde and the Be~SOr mean zoo on the other gripper
arm ~lde panel on its other side. In order to be hela
in the position shown in Fig. lB the resllient bracket
430 must be deflected to an essentially planar
configuration rather than the configuration of Fig. 7B
which shows a bending of the upper bracket portion
about an angle alpha from the lower bracket portion.
When in the assembled configuration of Fig. lBJ it i8
to be understood that the spr~ng~like resilient biasing
properties of the bracket 430'urge the e~senti~lly
planar ace of the disc-shaped magnet holder 426
against the essentially planar cover plate 410 of the
sensor 400. As seen hereinafter w1th respect to Fig.
lB, movement of the second jcaw member 26 about pivot
point 222 causes the magnetic means 420 to slide across
J
~3~
-27-
the sensor mean 400, thereby changing the magnetlc
yield flux detected by the sensor element 412
MISTAKE DETECTOR CIRCVITRY
As mentioned above, cable 413 extending from
s the sensor mean 400 includes the leads 414, 416, and
418 which are connected to the circuit of Fig. 8A, The
circult of Fig. 8A is not located on the gripper arm
it~l, but on a circuit board remote from the gripper
arm.
As shown in Fix, 8A, leads 414 and 418 are
connected to ~12 volt and round, re~pectlvely. read
416 iB connected to a node 450 of the slgnal generating
means 367. Signal generating means 367 includes a
voltage division network which comprises resistor Rl6,
lS ~17 and Rl8. In the voltage division network a nod
451 occur between the connection of re~istor~ R16 and
Rl7 and a node 452 occurs between the connection of
resistors R17 and Rl8. Node 450 is connected by a
capacitor C6 to ground.
The low side of resistor Rl~ (node 451) is
connected by a lead 453 to storing means 369
illustrated as a sample and hold circuit, and
particularly to a non-inverting input terminal of a
llnear operatlonal amplifier 4S6 included thereln. The
sample and hold circuit further comprise NAND gates
458 and 460; a 14-stage binary counter 462; and, an
operational ampliier 464~ The inverting input
terminal of the OP AMP 4S6 is connected both to the
output terminal of the OP AMP 464 and through a
resistor Rl9 to the inverting input terminal of the OP
UP 464. The output terminal of the OP AMP 456 is
connected to a first input terminal of the NAN 45~
The second input terminal of the NAND 458 is connected
(
3~3
-28
by resistor R20 and capacltor C7 in 3erles both to the
output terminal of NAND 460 and Jo the clock input pin
of the counter 462. The second input t:erminal of the
NAND 45~ s also connected to both the output terminal
of NAND 458 and to a first input termirlal of NAND 460
through resistors R20 and ~21. second input terminal
of NAND 460 is connected through a leacl 46~ to a lead
468 and a selectlvely closable calibration switch
467. Lead ~68, which carries a clocklng signal, i
connected to a reset pin ox the counter 462 through the
calibratlon switch 4~7.
Output pin 1, 2, 4-7, and 12-15 of counter
462 are each connected by one of the resistors R22 to a
voltage dlvislon network. The voltage division network
comprises nine resistors R23 arranged in series, tha
low side of each resistor connected (through a resistor
R22) to a corresponding output pin of the counter 462
and the hlgh wide connected (through a resl~tor R22) to
a neighboring output pin of the counter 462. Output
20. pin 2 ox the counter 462 is connected through its
associated resistor R22 to the non-inverting input
terminal of OP AMP 464 and through the resl~tor ~22 and
capacitor C8 to ground.
The circuit of ~19~ 8A also illustrates ln
more detail thy comparing means 368; the transmission
gate 370; and the mistake indicator/alarm mean 372.
In this respect, the comparlson means 368 comprises
both double" comparison means (such as operational
amplifier 470) and Miss" comparison means such a
operational amplifier 4~0). Similarly, the
transmission gate 370 comprises a "double" mistake gate
(including a multivibrator such a ~Dn-type Elip flop
472) and a Miss" mistake gate (including a similar
multivibra~or 482). the indicator alarm mean 372
J `J
3~3
?
-2~
includes lnverting drivers ~74 and ~4 and respective
LED3 such a "double" hED 476 and "mi0~" LED 486,
th respect to clrcuit elements used to
detect a l'double", the nvn-lnverting input terminal o
S the OP AMP 470 is connected Jo the low wide of resistor
~17 (node 452) while the inverting input terminal of OP
AMP 470 i 8 connected to the calibrated reference slgnal
occurring at the output terminal of the OP AMP 464.
the output terminal of the OP AMP 470 is connected to
the data input pin of the flip~1Op 472. The set
terminal of the flip~flop 47Z 18 grounded, but lt
termlnal l connected to the input terminal ox the
inverting driver 474. The clock pin of flip-~lop 472
i8 ultimately connected to a lead 468 which carries a
tlming pulse indicatlve of the point in tlme of a
machine cycle when the flip-f.lop 472 i8 to transmit the
comparison result to the indicator alarm means 372
to the point in time in whirh the separation of the
gripper jaw member 24 and 26 is to b* detected. The
reset pin o the flip-flop 472 is connected to a lead
477 which 3electively carries a reset pulse.
The output terminal o the driver 474 is
connected (1) through a re~i~tor R24 Jo t24 volts D.C.;
(2) Jo the cathode of LED 476 and through resistor ~2
to ~24 volts D.C.; and, (3) to the cathode of a diode
478, the anode of which is connected to a lead 479
which carries a signal indicative of a detected mistake
to unillustrated portions of the system which have need
to know of the mistake.
With the exception of the input terminals of
the OP AMP 483, the element 480, 482, 484, 486, and
488 used to detect a "miss" are connected in analogous
manner with the elements 470, 472, 474, 476, and 478 as
described above. however, the non-inv~r~ing lnput
terminal of the OP ASP 480 it connected Jo the
r
3~3
-3~
callbrated reference signal occurrlng at the output
~ermlnal of the OP AMP 464 while the inverting lnput
term$nal of OP AMP 480 is connected to the node 450
~th~ high side of ee~is~or R16).
For the embodiment of the elPctrical
circuitry associated with the Hall ~f~c~ sensor 400 a3
shown in Fig. 8~, operational ampliflers ~56, 464, 470,
and 480 are lncluded on a quad OP AMP chip; NAND gate3
458 and 460 are included on a quad 2-inpu~ NAND Schmltt
10 trlgger chip; and, flip-flops 472 and 4a2 are included
on a Dual "D" flip-flop chip. The resistor and
capacitor shown in the embodiment of Fig. 8A have the
values shown on the following charts:
Resistors
R16 - 100 ohm
R17 - 100 ohm
R18 = 4.7 K
Rl9 100 X
R20 - 100 K
R21 = 10 K
R22 = 200
R23 = 100 X
R24 = 10 K
R25 = 1.8 R
R26 = 10 K
-
Capacitors
C6 = 1 microF
C7 = 0.003 microF
C8 - 500 pico~
OPERATION
The operation ox the gripper arm and the
~3~3
-31
mistake detector are hereinafter described. the first
general phase of operation de~aribed h~rein~fter i8 khe
opening ox the gripper jaw such a takes place when an
insert is released for dropping onto thle raceway 18.
5 The second general phase of operation dlescribed
heeeinafter l$ the closing of the gripper jaws to
engage anotber insert between the gripper jaw 50 as to
pull the invert from its tack at thy insert ~tation~
The third general phase of operatlon described
hereinafter l the operation o the mi~t~ke detector
which determines whether the proper number of inverts
are engaged between the cloyed gripper jaws.
For the most part the ensuing ~iscu~sion o
the operation of the gripper arm and the mi take
detector a~ume~ that the normal operatlons of the
insertion machine are currently on-going and that
inltializatLon or set-up of the insertion machine has
already taken place. what is, k operation of the
insertion mach$ne is descrlbed herein a being for the
most part in the middle of a job. Where appropriate,
however, operating ~ep~ or re3ults that have impact or
pertain to machine set-up or calibratlon are also
de~crlbed. In this respect; from Flg. 4 and portion
of the ensuing discussion it is understood that the
operation ox a slow jog mode such as used in machine
jet up isO except for matter of timing, similar to the
on-going operation. Also, following the description of
the operation of the mistake detector the calibration
operatlon of the mistake detector it also described.
GRIPPER JAW OPENING OPERATION
At an apprvpriate point in the machine cycle
when the gripper jaws 24 and 26 are engaging an invert,
light from the LED 302 o opto-interrupter ox encoder
~33~3
32-
disc sensor 300 radiates through spaces between the
teeth on the encoder disc qo as to be incident upon
recelver 304, caving the recelver 304 to outpuk a true
signal to the inverting driver 312. Inverting driver
312 inverts the true signal to a false signa} for
appllcation to inverting driver 314. Invertlng driver
314 in turn inverts the false siynal to a true
signal. When the teeth of the encoder disc interrupt
the light between the LED 302 and the receiver 304, a
false signal appears at the output of the inverting
driver 314. Thus, a the encoder di3c rotates, a
series of pulses is produced. In the series o encoder
pulses generated by the 6~-tooth disc, the machlne man
shaft rotates 5~625 of the machine cycle (5.6~5 DMC)
between the leading edges ox consecutive true
signalsO The graphs ox encoder pulse trains generated
in this manner appear in Figs. 4 and 5, The encoder
pulse train is applied to NAND 316 and 318 ox the
-circuit shown in Fig. 3.
During operation the clock 324 is generatln~
clock pulses at a frequency determined by the manner in
whlch the pin of the clock 324 are connected. When
connected in the manner shown in Fig. 3 and de3cribed
herein, the clock 324 generates pulses at a 178
rate. Trains ox pulses from the clock 324 are shown in
Figs. 4 and SO Note that in Fig. 4 there are more
clock pulses relatlve to the number ox encoding pulses
than shown in Fig. 5. In Fig. 4I the machine is
operating at 4,500 machine cycles (MC) per hour
whereas in Fig. 5 the machine is approaching
10,000 MC.
The clock pulses from clock 324 are applled
to the first input terminal of NAND 326. Whenever the
second input terminal of the N~ND 326 is also true, a
ealse signal is applied from the NAND 326 to the false-
,1
~33~
-33-
actuated OR gate 328. When the other input terminal of
the false-aGtuated OR 328 i3 true, then pulses from the
OR 328 are applied to the clock lnput pin of the
prese~ta~le up/down counter 330.
Counter 330 counts up when pin 10 the
directional pin) is true and counts down when the
directional pin i3 ale The clock pulses of carry
out pin 7 of the counter 330 are seen i.n Fig. 4 and
5. In relation to the clock pulses from clock 324, the
fading edge of the output pulae~ prom the counter 330
oscur sub~tant1ally at the tame time the leading
edge of clock pulseR from the clock 324.
cot pin 1 of the counter 330 it ultimately
connected to the encoder disc ~ensar 300, so that the
15 reset pin of counter 330 receives a train of pulses the
frequency of which is related to the number of machine
cycles occuring per hour. The leading edge o a pulse
in this encoder traln from the EON 332 causes the
counter to be feet thereby termlna~lng the output
pulse from the counter 330~ Thus, a seen in Fig. 4,
when the machine i5 operating relatively 510wly at a
rate of 4,500 MC per hour, the counter 330 can count up
a greater number of clock pulses beore it is reset by
the leading edge ox an encoded pulse from the EOR
332. In the graph of Fig. 5 on the other hand, the
counter 330 has sufficient time only to count up one
clock pulse before b ing reset.
The above descrlption of the operation
assu~e~ that the actuator timing disc mounted on the
30 machine drive shaft is ln a position to permit the
passage of light prom the LED 308 to the receiver
310. Under such circumstances the actuator is
activated, and hence the 11nkage 30 causes the second
jaw member 26 to be urged toward a contacting
relationship with the first jaw member 24. The
~33~3
-3~-
actuator timing disc has patterns on its circumference
to obstruct the position of light from the LED 308 to
the receiver 310 at points in the machine cycle in
which It is desired for the second jaw 26 to open with
respect to the jaw 24 as a result of the actuator
activation. When this occurs, the absence Oe light at
the receiver 310 causes output from the inverting
driver 346 Jo go alse. This false signal is applied
to the second input of the EOR 350. The first input
terminals of the OR 350 still receive a true slgnal
from the flip-flop 342 since no clock pulse has been
applled to the flip-flop 342 to cause the flip~flop 342
to be effected by the false signal appearing at the ED"
pin (pin 5) of the flip-~lop 342. The true gnat from
the Q output of the flip-flop 342 keep3 the solenoid
drive at a true level meaning that the solenoid 28 18
activated and that the jaws 24,26 retain together
Since the EON 350 now receives a true signal
erom the flip-flop 342 and a false slgnal from the
inverting drLver 346, the output of the EON 350 goes
true. This true signal is inverted by the inverting
driver 356 to be false. The false signal Erom the
inverter 356 i5 seen in Figs. 4 and 5 as dropping to a
false level in the portion of the graph labeled
compare Output".
The false signal from the inverting driver
356 li.e. the "compare output" signal) is used in two
ways. First, it is used to reverse the direction of
the counting of the counter 330. In this regard, the
3~ false signal from inverter 356 l applled to the data
input pin (pin 9) Oe the flip-flop 334 which causes the
Q output pin to go false when the next enco.ler pulse s
received at the clock input pLn oÇ the flip-flop 334.
The false output Oe flip-~lop 334 at the Q terminal
causes the counter 330 to change direction that is, to
~33~3
count down). Second, the false signal from the
inverting driver 356 is used to keep the EON 332 prom
resetting the counter 334 while the counter 334 is
counting down.
As mentioned above, the false signal from the
inverting driver 356 causes the Q output terminal of
the flip-flop 334 to go false. This false signal is
also applied to the NAND 326 and the EOR 358. A false
signal applled to NAND 3~6 keeps the false-actuated EOR
328 rom pasting clock pulses Jo the counter 330 while
the counter is counting down. A false signal appIied to the
OR 358 allows the EOR 328 to pass encoder pulses to
toe counter 330 rather than clock pulses.
Thus, when the direction of the counter 330
it changed so that the counter 330 counts down, the
counter 330 no longer counts clock pulses but encoder
pulses. When the number of encoder pulses counted down
equals the number ox clock pulses counted up, the
carry-out pin (pin 7) ox the counter 330 causes a
gignal to be applied to the clock terminal of the slip
10p ~42 so the Çalse signal appearing at the ~D~ pun
i9 clocked through the fllp-10p 342 and a false signal
appears at the output terminal. false signal at
the Q output terminal of the fllp-flop 342 deactivate
the jaw actuator 2~. Deactivation of the jaw actuator
means that the plunger 92 is free to Hall downwardly,
as does the linkage 30. Downward action of thy linkage
30 causes the second jaw member 26 to pivot about pivot
pin 178 in a direction away from the first jaw member
3G 24~ The false signal at the Q output terrninal of flip-
flop 342 also, when coupled with the false signal from
the inverting driver 346, causes the compare signal
(the output of the inverting driver 356) to again go
true, thus enabling the clock 330 to start counting in
'J
~L~33
-36
an up direction and enabling the EOR 328 to pass clock
pul8es to the counter 330 rather than encoder pulses.
From the foregoing it is seen that an
advantage of the invention is making thle time at whlch
5 the jaw actuator it selectively activatled and
deac~iva~ed dependent upon the speed in con~unation
with which the grlpper arm operate. A Rhown in Flg.
4, when the machine it operating at ~,500 MC per houry
a delay of 15 DO occurs between an indication from the
actuator timing disc that the actuator it to be
deactivated and the actual deac~lvation. In F1g. 5
where the machine operates at 10,000 MC per hour, on
the other hand, the delay is 7 DMC. Lets delay for
deactivation of the actuator 1g required at higher
machine operating speeds than lower machine operating
speeds for the gripper arm to carry out operations that
result in precise placement of an article engaged and
released by a gripper arm. By making the ~lme o the
deact1vation of the jaw actuator dependent upon the
speed oE tha machlne, an operator can jet up a machine
in a 810w jog mode for a gripper arm to depos1t an
article a a precise location on tran~por~ mean with
confidence that when the machine 1s operating at a
higher speed essentially the same precise placement of
the article will occur.
GRIPPER ARM JAW CLOSING OPERATION
It ha been described above how the second
jaw member 26 opens with respect Jo jaw member 24 after
the jaw3 24,26 had previously been in contacting
relation. The preced$ng di~cu~sion provides the man
kited in the art with ample understanding of how,
once the jaw ~6 has been opened relative to the jaw 24,
the jaw 26 again closes to engage whatever article may
`--
33~L3
~37-
be between the jaws 24 and 260 Hence9 the ollowing
d~scuRsion of the closing of jaw 26 doe not lnclude
features analogous to those already described, but
rather the relationship of solenoid force requirements
and spring force requirement involved in the closing
of jaw 26.
When the actuator timing diva it again in a
position Jo permit l~ght.to pa3s from l,ED 308 to
receiver 310, the input Jo the solenoid 28 goes true to
activate the solenoid 2S. The act1vation of solenoid
28 creates a force on cable 206 Jo move cable 206 in an
upwards direction. The amount of force created by the
solenoid depend upon such factors as the force curve
for the particular solenoid used and lts duty cycle
The force curve for the pull-type solenoid described
herein is shown by line 500 in Fig. 15 for a solenoid
operating for a duty cycle f=l/4 (f - non" time divided
by the sum of Non" and "off' time. For the solenoid
shown, a voltage of 54 volt DC it applied upon
activatlon or lO0 milliseconds. When the ~ol~noid is
seated the voltage it reduced to 27 volt DC with a
r@sultant holding force of 9 pounds .
The graph of jig. 15 shows solenoid force and
spring force plotted as functions of both the solenoid
25 position (upper X axis) and the position of the upper
jaw (lower X ' axis) . The X axis oP Fig . 15 refers to
the extension of the plunger 92 of the olenoid 28, the
Nero posi~cion of the X axis being the seated position
of plunger 92, the X' axis oE Fig. 15 reers to the
distance 3epara~ing the lower jaw member 24 and the
upper jaw member 26. The zero of axis X' is offset by
about û.05 inch with respect to the zero of axis X,.
this offset occurs because after the upper jaw 2~
contacts the lower jaw 24 the solenoid plunger 92
35 . travels another 0.50 inch before seatlng. Though
J
~233~3
-38-
off~e~, the acales for the axe3 X and X' are the same
wince the distance rom pivot point 222 to the polnt
where cable 206 attached to pin 205 ~g substantially
Q~ual to the di~tanc~ from the pivot point 222 to the
position of jaw 26 which selectively con~act~ jaw 24.
AGcordingly, and.in view of t:he relationship
described above, for jaw 26 to contact the jaw 24 the
plunger 92 must be retracted 0~125 inches. When an
invert it to be engaged between jaws 24 and 26~ the
plunger need be retracted 0.125 inches less the
thickness of thy ~nser~. Thus, for an insert 0.005
inch thick a shown by line 502 ln the graph ox Fig.
15, the plunger 92 must be retracted 0.125 înch - 0O005
inch = 0.120 inch. Further, if it be desired that the
~ns~rt be held by a holding force of 6 pounds, for
example, the plunger 92 must be retracted a further
amount which will extend the expansion spring 122
sufficiently Jo that the 6pring 1~2 will cause the
1nsert to yea a 6 pound holding force
A~uming, for example, that the spring 122
ha a 20 pound per inch spring rate, if the spring 122
were not preloaded the spring 122 would have to be
extended 0.3 inches Jo achieve the 6 pound holding
force. The distance of retraction of the plunger 92 to
both move the 0.120 inch to displace jaw 26 and the 0.3
inch required to extend the spring 122 requires a total
retraction of the plunger 92 on the order of 0.42
inch. Plunger retraction for such a great distance
requires considerable time and result in lower
solenoid forces. According Jo the prevent invention,
however, the plunger 92 need not be retracted a,3 inch
to extend spring 122. As described hereinbefore,
housing 202 preloads the spring 122 of jigs. } 80 that
the spring 122 is already extended Jo provide a
~tartins force of 5 pounds. Thus, when the solenoid is
~2~3~a~3
-39-
actuated the plunger is retracted approximately 0.120
lnch Jo thaw jaws 26 and 24 engage therebetween on
invert ox ~h~cknes~ 0.005 inch, and then retracted
further an additional 0.05 inch in order to extend the
expansion spring 122 an amount suficient to gain an
additional 1 pound holdlng force. The 0105 lnch
further expansion of springs 122 (equivalent to 1 pound
force) and i~3 preloaded expansion equivalent to 5
pounds force) give a total 6 pound holding for2e.
..
MISTAKE DETECTOR OPERATION
Fig. 12A show the relat$ve position of the
second jaw member 26 and the tnagnetic means 420,
partlcularly magnets 42~ and 424, wlth respect to the
pivot point 222. As the formerly open second jaw
member 26 pivoted About the pivvt point 222 to assume
the position of the jaw 26' shown by phantom lines in
Fig. 10, thereby closing upon the invert It the
magnetic mean 420 likewise pivoted about point 222 to
assume the position ox magnet holder ~26' (also shown
in phantom line3). Due to the Hall Efect, aR the
magnets q22 and 424 carried by holder 426 pivoted in
the plane of their exposed polar faces about the pivot
point 222, the flux denslty of their magnetic field as
detected by the sensor 412 changed. A the sensed flux
of the resultant magnetic field changed, the voltage
generated by the Hall Efect tensor 400 changed
proportionally. In this reyard~ it is recalled that
the sensor element 412 has a constant current appl$ed
~here~o whereby the voltage generated across the
electrical conductor included in the tensor element is
proportlonal to the magnetic field flux in accordance
with the well-known Hall Effect. The magnet 422 end
424, positionally biased by virtue of the resilient
TV
~3~
-40-
bracket 430, slid acro~ the SenSQr 400 ln accordance
with a ~lide-by mode. on sliding by the sensor rather
than approaching the sensor in a head-orl moder a
constant ~patlal relationshlp 13 maintained between the
plane of the exposed magnetic poles and the plane oE
the sensor element
The biasing unc~ion performed by the
re~ilien~ bracket 430 provides numerous advantage.
For example, the bracket keep the magn~s 422 and 42.4
at a uniform spacing away from the sensor 412. If a
uniform pacing were not mai~tainea~ the magnetlc let
experienced by the sensor 412 would not be uniform.
The biasing of the bracket 430 against the magnets 422
and 424 alto help to keep out foreign particle3 such
15 as dust Moreover, the biasing overcome3 problems
which might axise due to the gripplng of inert ox
different dimens$onal tolerances.
A shown in Fig. 10, the pivoting of magne'c
holder 426 as the second jaw member 26 clover tv engage
an invert cue the imaginary line 436 to pivot to
assume the position 436'. Recall that imaginary line
436 extends from the pivot po~n~ 222 to perpendicularly
bisect the line 428 connecting the centers ox magnets
422 and 424. Upon a~sumin~ the pivotal po~ltion in
FigO 10 as shown by the phantom lines, the point X
(the center of the magnetic field) at the intersection
of lines 428' and 426' is displaced along the Y axis of
Fig. lO by a distance y prom its prior position K Nat
the intersection of lines 42~ and 426~ when the second
jaw member was open with respect to the first jaw
member
The distance y i3 related to the distance x
separating the firs and second jaw members by the
expression
3~
\
, ,f
"I , Jo !~
~41-
x /AA~
_ fl _
y EBB
where A it the distance rom the pivot point 2Z2 to
the center of the magnetic field (point X and where BB
l the dlstance rom the pivot point 222 to the polnt
of the potential contact o the ~lrst and second jaw
members. The value of the ratio x:y is thus a non-
linear function of the ratio AA:~B~ For the 3peclal
case lllu~trated in Fig. 10 wherein the magnet 422 and
424 are arranged immediately next to one another (i.e.
the magnet Dave edge practically touching at thy
point K) the above relationship becomes essentially
linear over a portlon ox it range Jo thats
AA
x I _
y BB
Thus, the positioning of the magnets ~22 and 424
relative to one another it a actor in deter~4ning thy
nature of thy rela~ion~hip.
In Yig. 9 the analog voltage output of thy
Hall effect sensor 412 is teen a3 a function of insert
thickness (i.e. the distance x separating the flrst and
second jaw members at their point of potential
contact). When the irst jaw member 24 and the ~e~ond
jaw member 26 contact one another to the jaw is
"zlosed" with no insert engaged therebetween), the
analog Yolta9e output is slightly le~5 than 2 volts.
~5 When the distance x separating the jaw members 24 and
26 it about 0.1 inches, the sensor output voltage i5 in
khe neighborhood of 5.5 volts. From the graph nf Fig.
9 it can be seen that a .004 inch change in insert
thickne~8 result in about a 200 milivolt increa5e in
tensor output. The analog voltage output o the tensor
412 it applied on lead 416 to the circuit of Fig. 8.
The analog voltage output of sensor 412 on
~%~3~:~3
--42--
lead 416 it applied to the mistake indicating cirauit
365. In thi~ regard, the voltage output on lead 416 i8
applied both to the slgnal generating mleans 367 the
voltaye di~tlder network compri~lng resls~ors R16, R17,
5 and R18) and to the comparing mean 368 (i.e. to the
non-inverting input terminal of OP IMP 480). Signal
generating means 367 generake~ a f lr~t analog voltage
aignal on line 453 which l proportional Jo the analog
voltage on lewd 4}69 ~lgnal generating mean 367 al~30
10 produces a ~ecorld analog voltage signal a ns:)de 450
which ~3 a f lxed percentage greater than the voltage on
line 453 and a third analog voltage ~lgnal at node 452
which is a flxed percentage let Han the voltage on
lone 453. As teen hereinafter, voltages at node 450
and 452 are respectively used by the OP AMP 480 [to
determine lf none or too Jew articles (a "missn) are
engaged by the gripper arm] and by the QP IMP 470 lto
determine it zoo many articles pa "double" ) are engaged
by the gril?per arm In this r~39ard, the non-lnverting
20 input terminal of OP AMP 47û receive the analog
voltage slgnal from node 45~ which l a fixed
percentage lest than the voltage on line 4531 and the
lnverting input terminal of OP AMP 480 receive the
analog voltage signal f rom node 450 (which it a f ixed
percentage greater than the voltage on line 453).
The Miss OP AMP 480 compares the calibrated
analog reference voltage generated by the sample and
hold circuit 369 to the voltage signal at node 450
(which is a flxed percentage greater than the voltage
gnat on line 453). The voltage signal at node 450
corresponds to a lower limit of acceptable jaw
displaGement. If the output voltage at node 450 i6
less than the reference voltage, the output terminal ox
OP AMP 480 goes true to indicate that too few inse.rts
have been grabbed.
33
-43-
The "double" OP AMP 470 compares the
calibrated analog reference voltage to the voltage
signal at node ~52 which l a flxed percentage lets
than the voltage signal on lLne 453). The voltage
signal at node 452 corresponds to an upper limit of
acceptabl.e jaw dlsplacement. If the voltag2 at node
452 exceed the reference voltage (by reason of zoo
great a dls~ance ~epara~ing the gripper jaw 24 and
26), then the output terminal of OP ~M~ 470 goes trule
to indicate that too many in~er~ have been grabbed.
The value of resl~ors R16 and ~17 are so choeen that
the voltage at nodes 450 and 452 are at fix d
percentages above and below, respectively, the voltage
signal on line 453 to provide an acceptable tolcrance
lS range for insert thicknesses.
At a point in the machine cycle at which the
distance x separating the grlpper jaw member 24 and 26
iB to be checked (and thu6 the thlckness of the
insert/in~ert~ engaged therebetween), a timing pulse lo
applied on lead 486 to the ~lip=flops 472 and 482. If
either flip-flop 47~ or 482 it receiving a true slgnal
at its data input pin when a timing pulse it received,
the Q output pln of the re~pectlve fllp-flop goes true
~0 2S to ultimately activate an appropriate LED
indicative of the detected condition If, for example,
OP AMP 470 had a true output when flip-flop 472
receive a timing pulse, the Q output pin goes true so
that a true signal is applied to inverting driver
474. The output oP driver 474 goes false, so that LED
476 is activated to give a visible indication that a
"double" occurred. Once the mî~take indicator is
observed and rectifled, the operator can reset the
flip-flop by causing a reset pulse to be applied on
lead 477.
~3~3
-44-
It has been mentioned earlier that the sample
and hold circuit 369 generates a calibrated analog
voltage signal or application to the OP AMPs 470 and
480. The calibrated reverence voltage ls generated
when an operator (1) verities (during al portion of the
machine cycle in which the gripper arm of the insert
station is to grab an insert) thaw the gripper jaw
element 24 and 26 are separated by the proper distance
x (kaking into consideration the number of insert to
be engaged and thy thickness of each engagëd insert
(2) closes the calibration switch 467; and, ~3~ then
opens the calibration wick 467. When the switch 467
ia closed the voltage signal at node 451 is applied to
the non-inverting terminal of OP AMP 456. the circuit
369 hold the voltage at node 451 in binary form but
provide an analog output from OP AMP 464 which it used
as the calibrated analog reference voltage until the
switch 467 is again closed for another calibratlon.
thus, the present invention provides a mistake detector
that can be very eagily and accurately calibrated.
From the foregoing it 8 seen that the
present lnventlon provides a method of easily
calibrating the mLstake detectors a~ociated with eaah
of the plurality of gripper arms positioned along a
raceway of a multl-station insertion machine. In this
respect, a lay operator who need not be a skilled
technician can simply and quickly calibrate the mistake
detectors for each grlpper arm. The lay operator need
only approach insert statlon Sl; load the desired type
30 of insert3 into the hopper associated with insert
station Sl; jog the insertion machine 10 through a
portion of machine cycle during which tlme the operator
can verify whether gripper arm 161 is properly engaging
an appropriate number of insert Il at station Sl
(meaning that gripper jaw elements 24 and 26 are
3~
.. .
-45-
separated my the proper distance during a portion of
the machine cycle wherein the jaws engage the proper
number of inserts), close the calibration switch 467;
end, then open the calibration 3wl~ch 467. The lay
operator then move to insert station S2; loads the
desired type of inserts into the hopper associated with
1nsert station S2; jogR the machine 10 through a second
machine cycle to verify the engagement of grlpper arm
162 of a proper number of insert I2; closes the
calibration switch associated ~herew~th; and, closes
the a~ociated calibration switch. the lay operator
then move Jo invert station ~3 whereat analogous lop
are performed, and so on according to the number of
invert stations provided with the particular machine
being used.
An alternative approach for callbrating the
miatake detectors a~soclated with each of the plurality
o gripper arms is for the lay operator to load each
insert station AL, S2, and S3 with it respective
inserts. The operator then jogs the ln~ertion machine
through a portion of the machine cycle durlng which
time each gripper arm engages it re pectlve invert.
The operator then stops the machine and inspects Mach
gripper arm to verify that a proper number o inRerts
are engaged by each gripper arm. If all gripper arms
are engaging the proper number of inserts, the operator
then close3 a master calibration switch (~CS) which
loses the calibration switch for each insert station
Sl, S2, and S3. A sequence of closing and then opening
the matter cali~ra~ion switch enable each sample and
hold circuit to hold its calibrated analog reference
voltage until another calibration operation occurs.
While the invention has been particularly
shown and described with reference to the preferred
~3~3
,. .
--46~
embodiments thereof, it will be under~t:ood by those
skilled in t:he art that varlou~ al~cerations ln form and
detail may ye made thereln wi~chout departing from the
spirit and scope of the inventlon.
