Note: Descriptions are shown in the official language in which they were submitted.
~o~a~ ~
BACKG~OUND AND DESCRIPTION OF THE INVENTION
The present invention relates to live roller conveyors
used to transport articles along a predetermined path and, more
particularly, to zero pressure accumulation conveyors and
trigger assemblies therefor.
Live roller conveyors and, even more particularly,
accumulation conveyors, are well known in the art. Such accumu-
lation conveyors have, in the past, employed various mechanisms
for controlling the rotation of the conveyor rollers to allow
them to be selectively rotated or stoppea to accomodate accumu-
lation of the articles being conveyed by the conveyors. The
rollers are rotated to convey the articles to a collection or
accumulation location and, once one or more of the articles have
reached that location or locations, the rollers are stopped to
provide for accumulation.
One such conveyor and control mechanism is shown in
U. S. Patent No. 3,696,912 (Fleischauer et al.). That patent
discloses a live roller conveyor having a brake assembly which
is mechanically actuated by a trigger assembly which senses the
presence of the article at its desired accumulation location.
The trigger assembly is mechanically coupled by a cable or
chain to the brake assembly to cause the brake assembly to
engage a key on a driven shat which, in turn, drives the
conveyor rollers to lock the driven shaft against rotation.
The trigger assembly in that patent comprises a pivoted arm
with a roller at the top which exten~s into the path of the
articles and the roller is depressed by an article when the
article arrives over the roller.
Although the trigger assembly disclosed in the afore-
30 mentioned patent is quite suitable for use in the conveyance
--1--
~l%~3~7~
of almost all articles which are usually encountered in such
uses, the trigger assembly disclosed therein has a disadvantage
that at least one of the live rollers in each section in which
the trigger assembly is located must be removed to accom~date
the trigger assembly. This is disadvantageous where the
articles being conveyed are short in lengthj i.e., short in
the direction of the path in which the articles are being
conveyed, or where the bottom surface of the article which
rests upon the live rollers otherwise has poor traction qualities.
10 When the articles are short or have poor traction, a situation
may arise where suf~icient traction is absent to restore
movement to the article once it has been stopped due to loss of
driving traction because of the removal of the live roller in
order to accomodate the dead trigger roller. In such cases,
15 it would be advantageous if the trigger assembly could be
installed without the need to remove and lose any of the live
rollers.
In U. S. Patent No. 3,840,110 (Molt et al.), a trigger
assembly is disclosed for a live roller accumulation conveyor
20 which does not necessitate rem~val of any of the live rollers.
However, the trigger assembly shown in that patent has the
disadvantage that articles can be moved in only one direction on
the conveyor because the trigger assembly interferes with move-
ment of the articles in the opposite direction. In certain
25 conveyor installations, dual directional movement of the articles
may be desired, such as where the conveyor might be reversible
or where it may be aesirable at times to manually move the
articles backward or upstream on the conveyor to clear a jam.
The zero pressure accumulation conveyor and trigger
30 assembly of tne present invention overcome the several aforementioned
--2--
!
disadvantaqes of the prior constructions. A zero pressure
accumulation conveyor and trig~er assembly constructed in
accordance with the principles of the present invention
eliminate the need to remove any of the live rollers in the
conveyor, thus assuring maximum tractional contact between
the live rollers and the articles being conveyed at all times.
In a zero pressure accumulation conveyor and trigger assembly
incorporating the principles of the present invention, articles
being conveyed may be readily moved in either direction on
the conveyor without interference from the trigger assembly.
A zero pressure accumulation conveyor and triggex assembly
constructed in accordance with the principles of the present
invention is safe, quiet and simple in construction, thereby
substantially reducing the need for maintenance and in time in
lS assembling of the conveyor, and the need for maint~in;ng a
substantial spare parts inventory is also reduced.
In one principal aspect of the present invention, a
trigger assembly for sensing the presence or absence of articles
on a conveyor of the kina having a plurality of rotatable rollers
20 arranged in a plane and spaced from each other in the direction
of the path of travel of the articles being conveyed to convey
the articles is provided. The trigger assembly includes
elongate cam means and mounting means for mounting the cam means
to the conveyor for pivotal movement about an axis at ~r above
25 the axes of rotation of the conveyor rollers. The cam means
also includes irst leg means spaced from the mounting means
toward one ena of the cam means and extending upwardly ~etween
a pair of the spaced conveyor rollers when the c~m means is
mounted by the mounting means on the conveyor. ~he upper ena
3~ of the leg means is movable to a first upper position in which
--3--
6~
it extends above the plane of the conveyor rollers in the
absence of an article, and a second lower position in which
the upper end of the leg means is urged by an article moving
in either direction on the conveyor so that it is substantially
5 in the plarle defined by the plane of the conveyor rollers.
Sensing means is also included which is responsive to the
movement of the leg means and the cam means about the mounting
means for controlling the operation of the conveyor.
In still another principal aspect,o~ the present inven-
10 tion, the aforementioned trigger assembly includes roller
means rotatably mounted adjacent the upper end of the leg means
and extending ~etween the conveyor rollers~ The roller means
is rotatable about an axis which is substantially parallel to
the axes of rotation of the conveyor rollers and that axis of
15 rotation of the roller means r~m~in.~ below the plane of the 1'
conveyor rollers when the roller means is in its uppermost position.
In another principal aspect of the present invention,
the aforementioned brake assemblies are employed in combination
with a plurality of live rotatable conveyor rollers, drive
20means for rotating the conveyor rollers, and control means
responsive to the trigqer assembly to cause the drive means to
rotate the conveyor rollers when the trigger assembly leg means
is in its first position, and to cease rotating the conveyor
rollers when the trigger assembly leg means is in its second ~,,
25 pOsition. ,;
, In still another principal aspect of the present inven-
tion, the aforementioned control means couples a plurality of
the trigger assemblies and drive means to operate separate
sections of the conveyor rollers in either a singulation mode
30Or a slug mode.
6~
These and ol:her objects, features and advantages
of the present invention will become apparent upon considera-
tion of the detailed description of the invention to follow.
BRIEF DESCRIPTION OF THE DR~WINGS
In the course of this description, the drawin~s
will be frequently xeferred to in which:
FIG. 1 is a f~a~mentary perspective view of a
li~e xoller accumulation conveyor incorporating the
principles of the present invention;
FIG. 2 is a fragmentary plan view of the accumula-
tion conveyor, with certain elements thereof broken away,
as viewed substantially along line 2-2 in FIG. l;
FIG. 3 is a partial side elevational view of the
accumulation conveyor, with portions thereof broken away,
as viewed su~stantially alon~ line 3-3 of FIG. l;
~IG. 4 is a partial broken plan view of one full
section and two partial additional sections of the drive
shaft, driven shaft and pulleys in the preferred embodiment
of accumulation conveyor of the present invention;
FIG. 5 is a par-tial broken end elevational view of
a preferred embodiment of brake assembly of the conveyor
assembly of the present invention as viewed substantially
along line S-5 in FIG. 2;
FIG. 6 is a partially broken side elevational
view of the brake assembly as viewed substantially along
lîne 6-6 in line 5;
FIG. 7 is a partially broken end elevational view
of one preferred embodiment of trigger assembly of the
present invention for use in the slug mode of operation of
the conveyor of the present invention and as vie~ed sub-
stantially along line 7-7 in FIG. 2i
FIG. 8 is a broken side elevational view of the
last-mentioned trigger assembly as viewed substantially
along line 8-8 in FIG. 7;
FIG. 9 is a partially broken end elevational view
of another preferred embodiment of trigger assembly of
the present invention for use in the singulation mode of
operation of the conveyor of the present invention;
FIG. 10 is a broken side elevational view of the
last-mentioned trigger assembly as viewed substantially
along line 10-10 of FIG. 9;
FIG. 11 is a schematic view showing a preferred
pnel~atic control system for four accumulation conveyor
sections for controlling the conveyor in the slug mode;
E7IG. 12 is a partial plan view o~ a preferred
embodi.ment of conveyor of the present invention showing
the positioning of the control elements shown in FIG. 11
for the slug mode of operation;
FIG. 13 is a partial cross-sectioned side
~ elevational view of the conveyor as viewed substantially
along line 13-13 in FIG. 12;
FIG. 14 is a schematic view showing a preferred
pneumatic control system for four accumulation conveyor
sections for controllin~ the conveyor in the singulation
mode;
FIG. 15 is a partial plan view of a preferred
embodiment of conveyor of the present invention showing
the positioning of the control elements shown in FIG. 14
for the singulation mode of operation; and
_fi_
`~Z0~
FIG. 16 is a partial cross-sectioned side elevational
view of the conveyor as viewed substantially along line 16-16
in FIG. 1~.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention
are shown in the drawings. With particular reference to
FIGS. 1-3, a preferred embodiment of live roller zero pressure
accumulation conveyor is shown incorporating the principles
of the present invention.
The conveyor, in general, includes a frame having
a pair of spaced parallel side channels 10 and 12 which
support a plurality of individually powered transverse
rollers 14 for rotation. The upper surface of the individual
rollers 14 are positioned in a common plane to define a
path line as shown by the unnumbered arrows in the drawings
along which conveyed articles are propelled in a direction
as indicated by the arrows. In addition, components of the
~Z~7~
preferred emb~di~ent of the zero pressure accumulation
conveyors shown in FIGS.1-3 include, generally, a trigger
asse~bly 16 which senses the presence of an article at a
specified location on the conveyor, a brake assembly 18
which restrains the motion of the rollers 14, and a drive
mechanism, aenerally 20, for imparting power to the rollers
14 to drive them.
The Vrive Assemhly
The preferred embodiment of drive assembly 20
will ~ir~t he discussed in detail.
~s shown best in FIG~ 4, the drive assembly
20 includes a cylindrical lineshaft or drive shaft 22 which
preferably exten~s continuously o~er the entire length
of the conveyor. The drive shaft 2~ is Freferably formed
of a hard metal, such as cold rolled steel
A plurality of independent torque tubes, generally
~4 as sho~n in FI~S. 5 ana S, are positioned concentrically
over the drive sha~t 22, one torque tube 24a-24c each being
located in longitudinally spaced sections a-c of the
conveyor as shown in FIGS. 1-4. The torque tu~es for each
of these sections a-c are denoted by the numerals 24a-24c,
respectively, in FIGS. 1-4. Each of the respective tor~ue
tubes is preferably formed of an organic polymer Gf which
nylon is preferred~ -A suitable nylon may, fGr example, k~
nylon S/6LNP RL-4540, although it will be understood that
other nylons as wellas other organic polymers may be
selected by one skilled in the art in the manufacture of
the torque tubes 24 after that per~on has appreciated fully
--8--
L67~
the invention disclose~ herein. The internal dia~eter of
the torque tubes 24 and ~he external diameter of the drive
shaft 22 are dimensio~ed and ~he m~terials from which the
drive sha~t 22 and torque tubes 24 are made as well as the
surface characteristi.cs of these elements are selected such
that when the drive shaft 22 is rotated, it will drive
the respective torque tubes 24 by frictional engagement of
the cylindrical surface of ~he drive shaft 22 with the
interior surface of the torque tubes 24.
Each of the torque tubes 24a-24c rotates in~epen-
de~tly of each other. This is accomplished by terminating
the torque tubes 24 such that separate independent tubes are
provided f~r each section a-c as shown in FIGS. 1-~. The
ends of-the torque tubes 24 at the boundarie~ of each
L~ section a-c are preferably mounte~ in a suitable bearing
26 attachea to the IramP of the conveyor by suitable means
~not sh~wn)~
~ plurality of slidable pulleys 28 are mounted
on each of the torque tubes 24a-24c as shown in FIG5. 1-4.
The pulleys 28 are axially slidable back and forth along
their respective torque tubes 24 such that when they are
positioned axially in ~ne location they frictionally
engag~ their torque tube to xotate with their respective
torque tubes, but when they are displaced rrom that axial
position, they slip relative to their torque tubes s~ that
they do not rotate in unison with the latter. Such
operation is more concisely described in U. S. Patent
_g_
~2~ i t ~3
No. 3,650,375 tFleischauer et al). The pulleys 2e are als~
~referably formed of an organic p~lymer ~aterial, such as
an acetal resin of which Delrin is one suitable form.
A resilient belt 30, preferably formed of an
elastomeric materialt is looped about each of the pulleys
and a circumferential groove 31 in an overlying roller 14
of the conveyor as shown in FIG5 1-4~ Each of the ~elts
30 preferably comprises an O--belt in ~ross-section.
Althougll a plurali~y of pulleys 28 are shown in
the drawings on the torque tubes ~4, it will be understood
th~t the pulleys may be replaced by indentations cast
in~egrally with each of the tor~ue tubes as is known in
the art.
Where the pulleys 28 are employed, it m~y also
~e desirable to provide spaced collars 32, as shown in
FIGS. 2-4, fixed to the exterior sur~ace o r the torque
tubes at spaced locations to limit the axial movement of
the pulleys 28 and prevent intererence ~etween adjacent
pulleys.
It will be seen from the preceding description
of the drive assembly 20 that the driYe belts 30 and
rollers 14, the drive belts 30 an~ pulleys 23, the pulleys
28 and the exterior surface of torque tubes 24a-24c, and
the interior surface of torque tubes 24a-24c and the sur~ace
of drive shaft 22 are all in fric~ional engagement with
each other and will rotate in unison with each o~her ~ue to
such engagement, but may slip relative to each other under
~ T~a~e M~r k
-10-
~3il6~
certain conditions o~ restraint of certain of the elements
as ~7ill be described in more detail to follow.
The srake Assembly
The brake assembly 18 is shoh~n in detail in
FIGS. 5 and 6. The hrake assembly 18 includes an L-shaped
bracket 34, the vertical leg of which is preferably T-shaped
an~ is boltea by bolts ~6 to one of the side channels ]2. An
air cylinaer 38 which receives air from one of the trigger
assemblies 16 throu~h conduit 40 is mountea to the horizontal
leq of the ~racket 34 and a piston rod 42 extencs ~ownwardly
from tne cylinder 38 as shown in FIGS. 5 and 6.
The horizontal portion of the bracket includes a
Fair of downwardlyexte~dino flanges 44 bet~Jeen which clamDing
~eans 46 of the preseut invention are mountea. The clamping
means comprise a pair of shoes 4~ and 50 wilich may ~e ~ormed
of an orga~ic polymer or other suitable ~.aterial. The shoes
are preferably formed of tough ny~on, The shoes-48 and 50
are coupled to each other at one side by a pivot pin 52. ~ach
~f the shoes 48 and 50 includes a substantially semu-cylindrica
portion having a curved clampin~ surface 54 as shown in FIG. ~
which is adapted to be pivo~ed about pivot piD 52 lnto a~d out
of contacting relationship with a cylin~rical sleeve 56
located at each o~ the brake assembly locations The
cylinarical sleeve 56 is fixed to the torque tube 24 and the
sleeve is preferably formed o~ metal, such as al~num. The
sleeve 56 is prefera~ly bonded to its torque tube by a
suitable adhesive such as7 for example, LOCTITE 326 a~hesive,
activated by LOCTITE 7D7 activator, Thus~ the sleeve 56
always rotates with the torque tube 24.
~ T~a de Ma~ ~
67~3
The shoes 48 and 50 each include arms 58 and 60
extending from the cylindrical portion of the shoes opposite
the pi~Tot pin 52 as shown in FI~. 5. The end of the ~m6D
on the bottom shoe 50 is pivotally fixed adjacent the ~ottom
5 of downwardly extending flange 44 by a pin 62 between the
flanges and the upper arm 58 on the upper shoe 48 is fixed
to the piston rod 42 and is movable in the vertical direction
by the piston rod between the flanges 44.
Thus, depending upon whether air is ~resent or
absent in the conduit 40 from a ~iven trig~er assembly 16,
the up~er shoe 48 will be pivoted by piston rod 42 into either
a first position in which the clamping ~surfaces 54 are movec
out of contact with the outer surface of sleevP 56 to allow
the sleeve and its torque tube 24 to be rotated by the
drive shaft 2.2, or to a second position in which the clamping
surfaces 5a engage the s~eeve 56 to restrain their rotation
by the ~ri~e shaft.
~he Trigger Assembly
. The trigger assembly 16 will now be described,
first by referring in particular to FIGS. 7 and 8 which show
the trigger assembly for the slug ~.ode of operation of the
conveyor.
The trigaer assembly shown-in rIGS. 7 ana g
includes a horizontally disposed E-shaped cam 64 adjac~nt
each of the siae channels lO and 12. The cam 64 incl~des
-12-
~20.~678
three upwardly extending legs of the E, legs 66, 6~ and 70
in descending order of lenyth. The longest of the legs 66
includes a cam roller 72 which extends across the width of
the conveyor and i5 rotatably mounted between the extremities
of the legs 66 on opposite sides of the conveyor as shown in
FIG. 7. The upper surface of the roller 72, when an article
is absent, extends slightly above the plane of the tops of the
rollers 14 as shown in FIG. 8, but will be biase~ downwardly
by an article which is being conveyed when the article is
positioned over the roller 72. The roller 72 preferably
rises above the upper surfaces of the roller 14 by approxi-
mately 3/B lnch.
The intermediate leg 68 of the E-shaped cam 64 is
the pivot mounting for the cam. A rod 74 extends transversely
15 ac~oss the conveyor and is mounted between the side channels
10 and 12 as shown in FIG. 7 to pivotally mount the cam 64
to the side channels and allow the cam and, in particular, its
roller 7~ to pivot to the position show in FIG 8 as well
as to a lower position in which the upper su~face of roller
72 lies in the sa~e plane as the upper sur~aces of rollers 14.
The shortest leg 70 of the trigger-assembly 16
includes a counterbalancing weight 7S in the ~orm of a rDd
or tube which also extends transversely across the conveyor
and couples the legs 70 of the cams 64 on both sides of the
25 conveyor bed~ The weight of the counterbalance 76 and its
spacing from ca~ pivot roa 74 is s~ch that the roller 72
will be biased to its upward position as shown in FIG.
in the absence of any other forces.
-13-
6'7~
e aY.~s o. ~hc pivot rod 7fl, oi roLatic)ll ol ti~L' cc>n-
~eyor rol1ers 14 and o~ the cam roller 72 are preferably p~si-
tioned in a predetermined relationshi~ to each ~ther. The
axis of pivot rod 74 is preferably located in a plane in or
above the plane defined by the axes y of the rollers 14, and
the axis z of rotation of the cam roller 72 is preferably in
a plane belo~ the plane of the upper surfaces of the rollers
14 when roller 72 is in its uppermost position. When the cam
roller 72 is in its uppermost position, it preferably does not
extend more than 3/8 inch above the plane of the upper surface
of rollers 14. Such positioning, together with the configura-
tion of the E-shaped cam 64, allo~s the trigger to be mounted
on a conveyor without par~icular concern as to the direction of
flow of the articles. 5uch positioning and configuration will
allow and not impair the m~vement of articles in either direc-
tion on the conveyor as, for example, i~ it is desired to
manually backup some of the articles which have alxeady been
accumulated or run the conveyor in reverse.
It will also be noted that the con~iguration of the E-
shaped cam 64 and positioning and shape of its leg 66 is suchthat it is not necessary to remove any of the powered live rollers
14 to accomodate the trigger assembly. The leg fits up through
the space between adjacent rollers 14 and can mo~e between its
upper and lower positions without interference from the rollers
25 14. This is particularly advantageous where the articles being
handled are o~ short dimension in the-direction of the path in
which they are being con~eyed.
The trigger assembly shown in FIGS. 7 and 8 also
includes an L-shaped bracket 78 which is mounted by bolts
30 80 to the side channel 1~. Although it is preferred that the
. -1~-
6~7~
bracket 78 ~nd the o~erating components o~ the trigger assem-
bly be mounted to the side channel 12, rather than the side
channel 10 to which the brake assembly 18 has been mounted,
it will he understood that both the trigger assembly and the
brake assembly may be mounted on the same side channel. Mount-
ing of these respective assemblies to opposite side channels
is preferred, however, because it facilitates assembly and
maintenance The L-shaped bracket 78 also includes a horizontal
leg upon which a pneumatic air valve assembly, generally 82,
and an adjustable limit stop 84 are also mounted.
The air valve assembly 82 includes a valve body
86 having a T-fitting 88 with two conduits 40, as previously
described, and 9O coupled to the fitting. As previously
described, conduit 40 is co~lpled to the air cylinder 38 of
a brake assembly 18 as snown in FIGS~ 5 and 6. Conduit 9D
is coupled to the bottom of 'he valve body 86 as shown in
FIGS. 7 and 8, but of the valve body of the trigger in the
next upstream section of the conveyor. As shown in FIGS~ 7
and 8, the conduit 90 entering the bottom of the valve body
is from either the T-fitting on the next downstream trigger
; assembly or from the air supply as shown in FIG. 11, and the
conduit 90 extending horizontally to the left o the T-fitting
88 is to the next upstream trigger assembly
Pivotally mounted at 94 on the horizontal leg of
the bracket 78 is a cam follower arm 96 and roller 98. A
plunger rod 100 ex~ends into the valve body 86, as shown in
FIGS. 7 and 8, to operate the valve in the valve body 86.
The plunger rod 100 is preferably spring loaded upwardly to
-15~
~2()~67~
force the cam roller 98 against the underside of the cam
64 as shown in FIG. 8.
The limit stop 84 preferably includes a b~lt 102
which is threaaed upwardly through t~e horizontal leg of the
5 bracket 78 to act as an ad~ustable limit stop for the
pivotal movement of cam 64. The bolt 102 is adjusted so that
it also contacts the underside of the c~m 64 as shown in
FIG. 8 such that the cam roller 72 projects above the plane
of the tops of the rollers 14 by the desired distance as
previously described. Once the bolt 102 is moved to its
desired adjusted position, it is secured in that position
by lock nuts 104.
As previously ~.entioned, the triggex assembly 16
sho~m in FI~S. 7 and ~ is the trigger assembly which is
pre~erably employed in the slug mode of operation of the
conveyor. The preferred trigger assembly 16' for use in the
singulation mode of operation of the conveyor is show in
FIGS. 9 and 10. N~erous ones of the components in the
singulation mode trig~er asse~bly 16' are identical to
20 those previously d~scribed in the slug mode assel~bly 16
shown in FIGS. 7 and 8. Accordingly, like reference numerals .
will be employed to designate substantially like components
and where the components do differ in some respect between . .
the singulation and slug modes, the s~perscript ~'~ will
25 be employed to designate such components in the singulation
trigger assembly 16' which will now be aescribed.
-16-
~L2~
Essenti~lly, the major differences between the
previously described slug mo~e trigger assembly 16 and the
singulation trigger assembly 16 ' are somewhat different
air conauit couplings and the provision of an additional
pilot valve assemkly 106 in the singulation trigger
assembly 16'
The ~alve body 86' of the singulation trigger
assPmbly 16' includes a down~7ardly aepending T-fitting 88'
having a pair of conduits 108 which couple the valve bodies
~6' of the trigger asse~blies 16 ' in adjacent conveyor
sections to each other.
As shown in FIG. 9, a third conduit 110 extends
from valve body 86' to a T-fitting 112 on a pilot actutator
114 on each of the pilot valve assemblies 106, The other
15 conduit 116, extending ~rom the T-fitting 112 as shown in
. 10, ports air from the T-fitting 112 to the bottom of
the valve body 118 of the pilot valve assembly 106 in the
next downstream trigger assemhly 16' ~s shown in ~IGS. 1,
10 and 1~.
With the mechanica~ elements of the preferred embodi-
ments of zero pressure accumulation conveyors ana brake
assembly of the invention having ~ow been aescribed, a
description of the operation of the conveyor and its control
circuitry in both the slua and singulation modes will now
be described.
-17-
7~
The Operation in the Sluq Mode
Althou~h reference may be ~ccasionally made to
other figures in the drawings, the principal figures relied
upon in the descriptinn nf operation in the slug mode are
FIGS. 11-13 and, to some extent, FI~S 7 and S of the
slu~ mode trigger assembly 16. The ~rake assembly 18
and drive assembly 2n are su~stantially identical to each
other in both the slug and singulation modes.
Prior to describing the se~uence of operation
in the s~ug mode, it should be stated that the general
manner of operation in that mode is that anytime an article
A is removed from the conveyor, all of the upstream -
articles will advance one position simultaneously.
Referring now particularly to FIGS 11-13, it
will be initially assumed that an article A is located
in each of the accumulator sections a-d as shown. Thus,
an article Aa will be positioned over the cam roller~72 of
trigger assembly 16 in section a, an article Ab will be
positioned over cam roller 72 of trigger assembly 16 in
section b, etc~
Whe~ these c~m rollers 72 are depressed by the
articles A, the cam follower arms 96 of each of the respec-
tive valve bodies ~6 will also be depressed and, referring
to FIGS, 7 and 8, the valve in the ~alve body 86 will be
opened, allowiny air to p~ss ~rom the air supply shown in
FIG. 11, throu~h conduit 9 O to and through the valve body ~6
in section a,the T-fitting 88 and conduit 40, to the cylinder
-18-
i7~
38 of the brake assembly 18 also in section a. Thus,
cylinder 38 of brake assemb.~y 18 will be actuated to cause
the.piston rod 42, shown in FIGS 5 and 6, to m~ve dow~wardly
and to cause the clamping surfaces 54 of shoes 48 and 50
5 to clamp and restrain the sleeve 56 and tor~ue tube 24a
in section a, thus restraining rotation of tor~ue tube 24a
and isolating the driving force imparted by the continuously
rotating drive shaft 22 ~rom the conveyor rollers 14.
In this condition, air a~so passes from the ~-
fitting 88 in section a throuah con~uit 90 to valve bcdy 86
of the trigger assembly 16 in section ~. Because its cam
follower 96 is also depressed by article Ab positioned over
roller 72 of the cam, the valve in valve body 86 in section
b will, likewise, be opened, pnrting air to its T-fitting 8
to energize the brake assembly 18 in section ~ to secure
p~wer to the rollers 14 in that section. Air ~lill also be
ported throu~h conduit 9O to the next upstream valve body 86
in section c. Thus, it will be seen that all of the valves
in valve hoæ.ies ~6 in each of the sections and will be opened
to port air to the brake assem~lies 1~ in each of the sections,
stopping all of the rollers 14 because all of the articles
Aa-Ad desired to be accumulatea have been accumulated.
~en article Aa is removed from the discharge
section a of the conveyor, the roller 72 o the trigger
assembly 16 in section a will rise due to the orce exterted
by the counterbalance 76 sho~-n in FTG_ 8 ~he~ the roller
72 rises, the cam follower 96 in section a will als~ rise and
--19--
~2C~6~7~
the pll~nger rod 100, as shown in FIGS. 7 and 8, will move
upwardly by spring Dressure closing the val~e in valve body
86 in section a. When this valve is closed, the air supply
will be cut off to the entire system because all o~ the valve
bodies 86 are connected in series Accordingly, air will
no longer be supplied to conduit 40 to the cylinder.38 of
the brake assembly 18 in section a and the piston rod 42,
as shown in FIGS. 5 and 6, will rise causing the shoes 4~
and 50 to pivot apart and move out of contact with sleeve
54. Sleeve 54 is now no longer restrained by the brake
assembly and the driving a~tion of the continuously rotatiny
drive shaft 22 operates upon the interior of the torque
tube 24a to cause the torque tube to rotate along with its
pullies, O-belts and the rollers 14 in section a.
As previous~y mentioned, when air is cu~ off to the
valve body 86 in section a, air will no longer pass through
the T-fittin~ B8 of that valve body and conduit 90 to the next
upstream valve body ~6 of trigaer assembly 16 in section b.
Thus, even though the cam follower 96 is st.ill depressed by
the article Ab in section b, air is now absent from conduit
40 due to the closing of the valve in valve body 86 in
section a Absent such air, cylinder 38 of brake assembly 18
in section b causes the piston ro~ 42 of the brake assembly
to move upwardly in similar fashion as did the roa 42 in
section a to remove the restraint rom the torque tube 24b
in section b Thus, it ~7ill be seen ~hat because th~ .
respective trigger asse~blies in this slug mode are effectively
coupled to ea~h other in series, when air is shut ~ff at the
-20-
6~7~
valve body 86 in sectiona, the air will be secured througho~t
the entir~ system. O~ce this air is secured, all of the
brake assemblies will be deenergized, causing all of the
articles Ab-Ad to advance simultaneously until the then
next lea~ article Ab enters section a and contacts the roller
72 of the trigger assembly 16 in section a.
Once the article Ab contacts the roller 72 in
section a, the v~lve in valve body 86 in that section will
- again be opened to port air ~ia T-~itting 88 to the conduit
40 and cylinder 3~ to reseet the brake assembly 18 in section
a, and through conduit 90 to the ~alve body 86 in section ~.
If article Ac has not yet arrived at cam roller 72 in section
b, the valve in vlave body ~6 in section b will remain
closed, causing the brake assembly 18 in section b to remain
deenergized and allowing the rollers 14 in section b
to continue to operate until article Ac contacts roller 72
in section b.
Operation in the Singulation ~ode
. In describing the operation in the sinaulation
20 mode, frequent reference will be made primarily to FIGS. 14-16
and also to FIGS. 9 and 10.
In the sin~ulation mode, o~ly one of the articles
A will advance at a time~ Once it has l~ft its ~re~ious at-
rest position and is enroute to its destined accu~.ulation
25 position, the next article will begin to aavance to replacP
the enroute article~ The ~rticles do not all advance
simultaneously as in the Freviously described slug modeO
67~3
Again, it will initially be assumed that articles
Aa-Ad are present and occupy each of the respective accum~-
latinn positions in each of the sections a-d as shown in
~IGS. 15 and 16 In this condition, article Pa in sectiona
will have moved over cam roller 72 of tri~ger assembl~ 16'
in section a r article Ab will have moved over cam roller 72
in trigger assem~ly 16' in section b, etc.
In the sinqulation mode, air is supplied to all
of the trigaer valves simultaneously and in parallel from
the air sup~ly shown in FIG. 14 via condults 108. Thus,
unlike the slug mode, all of the valve bodies 86' are
eneraized and ready to port air depending upon whether an
article A is absent or Fresent in their res~ec,ive conveyor
sections~ A conduit 116 from the air supply to the valve
body 118 of pilot va~ve assembly lQ6 in section a also
sup~lies air to that ~alve body ready for opening of the
valve.
Because article P.a has depressed cam roller 72
in section a, cam follower 96 will also be depressed. Thus,
20 plun~er rod 100 shown in FI~S. 9 and 10 will, likewise, be
depressed to open the valve in valve body 86' in section a
causing air to pass through conduit 110 to T-~itting 112 on
the pilot actuator 114 of pilot valve assembl~ 106 in section
a. When air is supplie~ to the pilot actuator114, it actuates
25 the valve in valve body 118 of pilot ~alve assembly 106
to open that valve allowing air to pass from con~uit 116 from
the air supply though conauit 40 to cylinder 3~ of the brake
i
~IL2~
assembly 18 in section a. Air to cylinQer 3~, as shown in
FIGS. 5 and 6, causes pis~on rod 4~ to move downwardly and
the shoes 48 and 50 to move together to clam~ sleeve 56
and torque tube 24a in section a. This clamping motion
restrains the movement of tor~ue tube 24a allo~ing the
continuously rotating drive shaft 22 to slip relative to
the tor~ue tube and denergize the conveyor rollers 14 in
section a.
In this ful~y loaded condition, i e articles
Aa-Ad on each of sections a-d, air will also be porte~
10 from the T-~itting 112 in ~ection a through conduit 116 to
the valve body 118 of pilot valve assembly 106 in secti~n b.
As previously mentioned, air is continuously ported via
conduit 10~ from the T-fitting ~8' in section a to T-fitting
88' in section ~.
Because the article Ab in section b, likewise,
is overlying the cam roller 72 in section b, c~m roller 96
of the trigger asse~bly 16' in section b will be depressed,
opening the valve in valve body 86' in section b to
cause air to pass through conduit 110 to the T-fitting 112
20on the Filot actua~or 114 of the pilot valve asse~bly 1~6
in section b. Air to this T-fitting 112 actuates the pilot
actuator 114 to open the valve in valve boay 118, causing air
to pass through conduit 4~to the cylin~er38 of the brake ~~
assembly 18 in section b. This air, th~reby, causes piston
25 rod 42 of cylinder 38 in section b to moYe downwardly clamping
. , .
~3 -
67~
the sleeve 56 and torque tube 24b to, likewise, restrain its
mDvement and allow driveshaft 2~ to slip relative to the torque
tube deenergizing the rollers 14 in section ~.
This same sequence follows upstream and, thus, all
of the rollers 14 in each of the sections a-d are stopped
because they each have an article Aa-Ad acc~ulated thereon.
It will now be assumed that articl.e Aa is remove~
from the conveyor section a. When the article Aa is remo~ed,
cam roller 72 will rise in section a causing the cam
follower 96 on the valve body 86' in sectiona also t~ rise.
When this hapDens, the valve in valve bo~y 86' in section a
will closd to secure air to conduit 110 to the T-fi.tting
112 on the pilot actuator 114 of the pilot valve assemhly
106 in section a. ~hen t~is ha~Dens, the valve in the valve
bod~ 11 of the pilot valve assembly 106 ~ill also close to
secure air from the air supply and con~uit 116 to conduit 40
and the cylinder 38 of the brake assembly 18 in section a.
with the brake assem~ly 18 deenergi~ed, the piston rod 42
of the brake asse~bly, as shown in FIGS. 5 and 6, will move
upwardly, causing the shoes 48 and 50 to move apart to
release the sleeve 56 and torque tube 24a an~ allow them to
aqain be rotated by the drive shaft 22 energizing rollers 14
in section a.
When the valve in valve bo~y 86' in sectiona is
closed, air is not only secured to the T-fitting 112 of
the pilot actuator 114 in section a, but it is also secured
to conduit 116 which leads to the valve body 118 of the pilot
-24-
3L24:~671~
valve assembly 106 in section b, Absent such air, conduit
40 leading from the ~alve bocy 118 to the cylinder 38 of
brake assembly 18 in section b will also be without air,
This will cause the cylinaer 38 of the brake assembly
18 also to be deenergized, thereby removing the restraining
force from torque tuble 24b and allowing the drive shaft 22
to rotate the torque tube 24b in section b, causing the
rollers 14 in section b to be energized. Thus, the next
article Ab will be advanced ~rom sectîon b to replace the
removed article Aa in section a.
It will be seen, however,that none of the remaining
articles in sections c and a will move at this time. They
will not move until article Ab has cleared the ca~ follower
roller ~2 in section h. So long as article Ab is still
present to depress the cam roller 72 and its cam follower 96
in section b, the valve in valve body 86' will be open to
port air ~rom conduit 108, through valve 86' in section b,
conduit 110, T-fitting 112 on the pilot actuator 114 of the
pilot valve assembly 106 in section b through conduit 116
to the valve body 118 in section c. Because the pil~t valve
assembly 106 in section c is open, this air will continue to
pass through the valve body 118, conduit 4~ to the cylinder
38 o brake assembly 18 in section c to actuate the brake
assembly to restrain rotation of the torque tube 24c in
section c.
Once article Ab has left the cam roller~72 in
section b, the cam roller will move up~Jardly, causing th~
-25-
~20~
valve in valve b~dy 86' in section b to close. W~en thi~
valve closes, air will be secured to conduit 110, T-fitting
112 and conduit 116 to the va~ve body 11~ of pilot valve
assembly 106 in section c Even though this valve remains
open because it is receiving air from conduit 110 ~rom the
depressed cam follo~7er 96 in valve body 86' in section c,
air will no longer be present in conduit 4~ to cylinder 38
of the brake assem~ly 18 in section c, deenergizing the brake
assembly an~ allowing the toroue tube 24c in section c to
now commence rotation to rotate the rollers 1~ in section c
and begin moving article Ac toward section ~ to replace
articl~ Ab ~hich has been moved to section a.
Thus, it will be seen that each of the articles
will move individually, one by one~in this sinaulation mode,
It will also be seen that even if articles have
been accumulated, for exam~le in sectionsa and b,and the
rollers 14 in ~hose sections have been sto~ped, articles
~c and Ad will continue to move to the upstream sections until
all of the sections are filled. ~his is because conduits 108
from the air supply as shown in FI~ 14 are coupled in
parallel to each of the valve bodies 86' so that the ~alve
bodies are ready to act anytime their respective cam followers
96 are not depressed.
Accordingly, assuming articles Aa and Ab are in
their respective accumulated position in sections a ana b,
~ut thzt article Ac has not ye~ arrivea at its position in
section c, cam roller 72 in section c will not be depressed.
In this condition, cam followe~ 96 in section c will be
-26-
6~
raised, closing ~he valve in valve body 86' in section ~,
thereby securing air to conduit llO to the T-fitting 112
of the pilot actuator 114 of the pilot valve assembly 106
in section c. In the absence of such air, the pilot actuator
5 11~ ~ill close the val~e in valve body 118 secuIiog air to
conduit 40 and the cylinder 38 o~ br~ke assembly 1~ in
section c, deenergizing the ~rake and allowing the torque
tube 24c in section c to be rotated by the drive shaft 22
to energi~e rollers 14 in section c. Thereby~ article Ac
is fed until it depresses cam roller 7~ in section c at
which time the rollers 1~ in section c will be deenergized.
It will be appreciated that although only four
sections of the conveyor have been shown in ~IGS 11-16,
that the number of sections may be increased or decreased as
15 desired without departing from the principles of the
present invention. It will al5~ be appreciated that although
the control circuitry of the present invention has been
described in terms of a pneumatic system only, hydraulic,
electrical and mechanical controls lnstead may ~e employed
20 and may be readily se-lected by those skilled in the art,
once they have fully appreciated the teachings of this
di~closure.
From the foregoing aescription, it will be seen
that the zero pressure accumulation conveyors and trigger
25 asse~bly described herein realize ~istinct advantages in
positively preventing the contact of articles bein~ accu~ula-
te~ with each other by provi~ing a construction for positively
-
-27- !
~25:~6'7~3
decelerating the live rollers 14 when each of the articles
arrives at their accumulation position. Moreover, the triqger
may be installed on the conveyor without the need to remove
any of the live rollers of the conveyor and the articles bei~g
5 conveyed by the conveyor may be moved in either direction
on the conveyor without impairment ~y the trigger assembly.
It will ~e understood that the embodiments of
the present invention which have been described are merely
illustrative of a few of the applications of the principles
10 of the present invention. Numerous modifications may be
made by those skilled in the art without departing from the
true spirit and scope of the invention.
r
;
-2~-
