Note: Descriptions are shown in the official language in which they were submitted.
BACXGROUND OF THE INVENTION
Twisted wire pairs are widely used in electrical equipment
for numerous reasons including the elimination of electrical inter-
ference, and providing more compact and easily identifiable wiring
arrangements in complicated circuits and wire harnesses. Because
of the extensive use of twisted wire pairs it has become desirable
to have highly productive means for prep'aring large numbers of wire
pairs which are cut to predetermined lengths and which have the
insulation stripped from one or both ends of each wire of the pair.
It is particularly desirable to have means which can automatically
prepare wire pairs cut to predetermined lengths with insulation
stripped from one or both ends and which can operate in conjunction
with automatic or semi-automatic circuit wiring machines.
Known methods for preparing twisted wire pairs with insulation
stripped from the wire ends include entirely manual operations
t `.;~
--1-- .
: 1~46744
using hand-held tools. Furthermore, U.S. Patents 3,779,290 and
3,815,449 disclose apparatus for stripping insulation from one
end of a wire pàir and wherein the wire pair is manually inserted
in the apparatus. U.S. Patent 3,827,465 discloses apparatus which
prepares individual wires of predetermined length and twists the
wires together after the insulation is stripped.
The present invention is directed to apparatus which will
automatically and continuously prepare predetermined lengths of
twisted wire pairs which have insulation stripped from opposite
ends of one or both wires of the wire pair. Such apparatus
according to the present invention is operable to prepare pre-
selected lengths of twisted wire pairs from a substantially con-
tinuous and uncut supply such as a large spool of pretwisted wire.
The apparatus of the present invention also provides improved
means for clamping the twisted wire pair and untwisting the wires
of the pair in the section of wire that is to form the end portions
of the wire leads whereby the insulation may then be cut and
stripped automatically. The untwisting mechanism included in the
present invention is operable to impart a controlled amount of
untwist to a portion of the twisted wire pair whereby the wires
of the pair may be cut and have a predetermined length of insulation
stripped from the wire ends formed by the cut.
The apparatus of the present invention further provides im-
proved mechanism for positioning an untwisted portion of a twisted
wire pair whereby the insulation on the untwisted portion may be
accurately cut without unwanted cutting or scratching of the
conductor wire and without ripping or tearing the insulation at
the insulation cut. The improved wire positioning mechanism of
the presen~ invention includes plural cams cooperable with mechanism
for actuating insulation cutting blades whereby the untwisted portion
1~)467~4
of the wire pair is prQperly positioned for accurately cutting
the insulation without damaging the conductor wire.
The apparatus of the present invention provides
improved means for producing twisted wire pair of predetermined
length with insulation stripped from the wire ends and which is
adapted to be operated in conjunction with automatically
controlled wire connecting machinery or for other applications
where large quantities of twisted w;re pairs are needed.
In accordance with one broad aspect, the invention
relates to an insulation cutting mechanism for cutting the
insulation of each wire of a wire pair comprising: a pair of
opposed insulation cutting blades disposed substantially for
reciprocating movement toward and away from each other between
open and closed positions; actuator means for moving said
insulation cutting blades toward and away from each other; a
first pair of cams disposed for movement to engage the wires
of said wire pair for moving said wires toward a position for
cutting of the insulation by said insulation cutting blades; and,
a second pair of cams movable with respect to said first pair
- of cams for engaging said wires sequentially after said wires
have been engaged by said first pair of cams to move said wires
further toward said position.
~'
B
1~46744
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a longitudinal side elevation of the cutting and
insulation stripping apparatus of the present invention;
Fig. 2 is a plan view of the apparatus of the present invention;
Fig. 3 is a side view, partially sectioned, taken from the same
direction as the view of Fig. 1 and oh a larger scale;
Fig. 3a is a continuation of Fig. 3 from the line a-a of
Fig. 3;
Fig. 4 is a view taken along the line 4-4 of Fig. 3;
Fig. 5 is a view taken su~stantially along the line 5-5 of
Fig. 3;
Fig. 6 is a section view taken along line 6-6 of Fig. 3a;
Fig. 7 is a plan view of the clamping mechanism shown in
Fig. 6, and taken from the line 7-7 of Fig. 6;
Fig. 8 is a view taken substantially from the line 8-8 of
Fig. 3a;
Fig. 9 is a section view taken from the line 9-9 of Fig. 3a;
Fig. 10 is a section view taken from the line 10-10 of Fig. 8;
Fig. 11 is a section view taken along the line 11-11 of
Fig. 3a;
Figs. 12 through 17 are detail views of the insulation cutting
blades and wire positioning cam mechanism in various positions
wherein Figs. 13, 15 and 17 are taken from the line 13-13 of
- 3a -
1~46744
Figs. 3a and Figs. 12, 14, and 16 are section views taken from
the respective numbered lines shown on Figs. 13, 15 and 17;
Fig. 18 is a front elevation of one of the wire guides;
Fig. 19 is a view taken from line 19-19 of Fig. 16, showing
the insulation cutting blades in the closed position;
Fig. 20 is a detail view taken from the line 19-19 but on
a larger scale than the view of Fig. 19;
Fig. 21 is a detail view of one of the insulation cutting
blades; and,
Fig. 22 is a plan view of a length of twisted wire pair
prepared by the apparatus of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Figs. 1, 2, 3, and 3a of the drawings, a cutting
and insulation stripping apparatus is shown and generally desig-
nated by the numeral 22. The embodiment of the apparatus 22 illus-
trated is designed to be moùnted on a bench or work stand 23, shown
in part. The apparatus 22 is characterized by a rugged metal frame
24 on which is mounted a wire feed mechanism, generally designated
by the numeral 26, which is slidable along the frame 24 in response
to actuation of a reversible or double acting pressure fluid cylinder
type actuator 28. As shown in Fig. 1, twisted wire pair 30 of in-
determinate length is conducted to the feed mechanism 26 from a
source of supply such as a large spool or the like, not shown. A
prefeeding or dereeling mechanism 32 may be used to reduce the
pulling effort required of the feed mechanism 26. Prior to
entering the wire feed mechanism 26 the twisted wire pair 30 is
passed through a detection device 34 for signalling the presence
of a splice in the wire or a gap in the wire insulation cover.
The twisted wire pair is fed from the feed mechanism 26 through
a releasable clamp mechanism 36 and through a telescoping guide
tube 38 to respective wire and insulation cutting blade assemblies
1~46744
40, 42, and 44 to be disclosed in greater detail herein. The
wire and insulation cutting blade mechanisms 40, 42, and 44 are
disposed in a support 46 fastened to the underside of the frame 24.
A drawer 48 is disposed below the support 46 for collecting in-
sulation pieces which are removed ~rom the twisted wire pair.
The apparatus 22 also includes a wire clamping and untwisting
unit 50 which will also be disclosed in greater detail herein. The
untwisting mechanism 50 includes a housing 52 which is slidably
supported on the frame 24 and is connected to a slide 54. The
slide 54 is connected to a second reversible pressure fluid cylinder
type actuator 56 mounted on the frame 24. A tray 58 is fastened to
the frame 24 for collecting twisted wire pairs which have been cut
to predetermined lengths and removed from the untwisting mechanism
50. The frame 24 including the aforementioned mechanism is mounted
on a cabinet 60 which contains suitable control elements for con-
trolling the operation of the apparatus 22.
Referring particularly-to Figs. 3 and 4 the frame 24 is charac-
terized by having an elongated channel 62 in which a slide 64 is
disposed and retained for sliding movement in the channel by re-
taining rails 66. The slide 64 is connected to a bracket 68 whichprojects through an opening 70 in the frame and is, in turn, con-
nected to the end of an extensible piston rod 72 of the cylinder
actuator 28. The feed mechanism 26 includes a support 74 which
is fastened to the slide 64. As shown in Fig. 3 the support 74
includes a recess in which is mounted a member 78 disposed on
elongated pins 80. The pins 80 are disposed in suitable bores in
the support 74 and are arranged to include springs 82 disposed
around the pins and engaged with the support.
The springs 82 are retained by suitable nuts, as shown. The
feed mechanism 26 is further characterized by spaced apart exter-
nally toothed rollers 84 rotatably mounted on the member 78 and
the support 74. Flexible toothed belts 86 are trained, as shown,
1~46~49~
around respective pairs of rollers 84 mounted on the support 74
and the member 78. Idler rollers 88 are also disposed on the
support 74 and the member 78 for guiding and supporting~the belts
86.
The feed mechanism 26 is driven by a rotary electrical
stepping motor 90 which is mounted on the support 74 and includes
an output shaft 92 on which a roller 84 is mounted. The motor 90
is of a well known type, commercially available, which is respon-
sive to an electrical signal to rotate a predetermined amount, and
to be precisely braked to stop when deenergized to give rotary
position control to the shaft 92, and accordingly the belt 86
mounted on the support 74.
The twisted wire pair is fed through the feed mechanism
between the two belts 86 which are pressed into engagement with
the wire by the spring biased member 78. Accordingly, the twisted
wire pair 30 may be linearly fed through the feed mechanism 26 a
controlled amount in accordance with a predetermined pulsed elec-
trical signal conducted to the motor 90, which results in a pre-
determined linear travel of the belts. The twisted wire pair is
conducted to and from the belts 86 by guide tubes 94, Fig. 3.
Beyond the feed mechanism 26, in the direction of travel of
the twisted wire pair through the apparatus 22, is disposed the
wire clamping mechanism 36 including cooperable clamping jaws 31
and 33 between which the twisted wire pair is fed. The jaws 31
and 33 are biased to separate from each other by a spring 35 which
moves the jaw 31. The jaws 31 and 33 are disposed in a housing 37
which is fastened to the slide 64. A fluid actuated plunger 39
is disposed in a bore 41 in the housing 37 for actuating the jaw 31
to clamp the twisted wire pair in response to a pressure fluid
3~ signal conducted to the bore 41 by a conduit 43 (Fig. 4) connected
to the bracket 68. Suitable passage means in the bracket 68 and
~46744
the slide 64 provide for communication of pressure fluid to the
bore 41. A spring 45 in the bore 41 biases the plunger away from
the jaw 31 when the bore is vented.
Referring to Figs. 3, 3a, and 5 the twisted wire pair is
guided beyond the clamping mechanism 36 through the guide tube 38
which also comprises a telescopic inner tube 45 removably connected
to the housing 37. The outer tube 38 projects through and is
secured in a support member 98. The inner tube 45 moves with the
clamping mechanism 36 and the feed mechanism 26 in response to
movement of the slide 64. The housing 37 includes a projection
100 which is conne~ted to a guide bar 102. The guide bar 102
projects into a channel 104 formed in a lower support member 47
of the support 46.
As shown in Figs. 3, 3a, and 5 the supporting means for the
wire positioning and insulation cutting blade mechanisms 42 and 44
includes the upper support member 46 suitably fastened to the frame
24. A lower support member 47 is fastened to the member 98 and
to a support block 106 disposed at the opposite longitudinal end
of the support members 46 and 47, as shown in Fig. 3a. The member
47 and block 106 are suitably secured to the upper support member
46 to hold the upper and lower support members in spaced apart
relationship. The support members 46 and 47 are respectively
characterized by a plurality of transverse grooves 108 and 110,
aligned one set with the other, which comprise guides in which
are movably fitted the insulation cutting blade mechanisms 42 and
44 and the set of wire cutting blades 40, the latter set of blades
being shown also in Fig. 9
Figures 3, 3a, and 9 illustrate means for actuating the blade
mechanisms 40, 42 and 44 to move in a reciprocating manner in the
grooves 108-110. Spaced apart pairs of actuating levers 112 and
114 are respectively pivotally mounted on pins 116 secured to the
1'~46744
frame 24. The levers 114 are connected to parallel elongated rods
118 which project through suitable openings in the blade mechanisms
40, 42, and 44. As shown in Fig. 9, the levers 114 are connected
at their upper ends to a pressure fluid cylinder actuator 120,
which includes a piston 122 and piston rod 124. Referring to
Figs. 1 and 3a also, the levers 112 are similarly connected to a
pressure fluid actuator 126 identical to the actuator 120. Suit-
able conduits provide pressure fluid to the actuators 1,0 and 126
to reversibly pivot the levers 114 and 112 for opening and closing
the blade mechanisms 40, 42, and 44 to cut the insulation and wire
of a twisted wire pair.
Referring to Figs. 3a, 6 and 7 a wire gripping device 130 is
removably disposed between the support members 46 and 47. The
gripping device 130 includes housing parts 132 and 134 which are
suitably flanged on their lower side to fit in one of the grooves
110 on the support member 47. Referring particularly to Fig. 6,
the housing part 134 includes a stepped bore 136 fitted with a
plug 138 to form a cylindrical chamber in which is disposed a
piston 140. The piston 140 includes a rod 142 which is connected
to the housing part 132. As shown in Fig. 7 passages 144 and 146
are formed in the housing part 134 and are in communication with
the bore 136 on opposite sides of the piston 140 whereby pressure
fluid may be alternately supplied to the bore to cause the housing
parts 132 and 134 to move toward or away from each other. Wire
gripping jaws 148 are removably mounted on the housing parts 132
and 134 as shown in Fig. 6. The gripping device 130 is normally
positioned adjacent to the wire positioning and insulation cutting
blade mechanism 42 to define one end of the section of twisted
wire pair which is untwisted prior to cutting and stripping of the
insulation.
--8--
1~46744
The apparatus 22 further includes means for untwisting a
section of twisted wire pair whereby insulation may be removed
from the ends of a predetermined length of twisted wire pair
and an untwisted section of each conductor wire is provided for
making terminations. Referring to Figs. 3a, and 8 there is illus-
trated the wire gripping and untwisting unit 50. The slide 54 is
disposed in the channel 62 formed in the frame 24 and includes a
bracket 150 connected to the piston rod 152 of the fluid actuator
56. The actuator 56 is mounted on the frame 24 generally in align-
ment with the actuator 28, and is operable to reciprocably movethe untwisting unit 50 respectively away from and back to the
support members 46 and 47 starting at the position shown in Fig. 3a.
Referring to Figs. 10 and 11 also, the housing 52 includes an
opening in which a cylindrical casing part 154 is rotatably mounted
on bearings 156. The casing part 154 is characterized by a cyl-
indrical bore 158 which intersects a rectangular opening 160 in
which are disposed wire clamping jaws 162 and 164. The clamping
jaw 162 includes a longitudinal groove 166 and the jaw 164 includes
a longitudinal flange 168 which may be moved into the groove 166
to clamp the twisted wire pair. The jaws 162 and 164 are biased
away from each other by plural pairs of coil springs 170 suitably
retained in recesses formed in the jaws as shown. The jaw 164 is
engaged with a piston 172 disposed in the bore 158 which may be
actuated by pressure fluid to move the flange 168 into the groove
166 to clamp the twisted wire pair. Pressure fluid is supplied to
and vented from the bore 158 by way of a conduit 174 which is in
communication with the bore 158 and with a circular manifold
member 176. The manifold 176 is characterized by two concentric
channels 178 and 180 which are interconnected by radial passages
182 to provide for conducting pressure fluid to and from the
bore 158.
1~46744
As shown in Figs. 3a, and 10 the rotating casing part 154
includes a reduced diameter portion 155 which may be disposed
directly adjacent to the insulation cutting blade mechanism 44.
The casing part 154 is retained in the housing by a cover 184
which includes a funnel shaped opening 186 aligned with the groove
166 in the jaw member 162.
The casing part 154 is also fitted with a drive sprocket 188
which is engaged with a toothed belt 190, as shown in Figs. 3a,
and 8. The belt 190 is also engaged with a drive sprocket 192
mounted on the output shaft of a motor 194 disposed on the housing
52. The motor 194 is an electrical stepping motor of the same
general type as the motor 90 and is responsive to a controlled
electrical signal to rotate a predetermined number of complete
or partial revolutions. A cover member 196 is fastened to the
housing 52 for enclosing the sprockets 192, and 188 and the
belt 190. The cover 196 is shown partly broken away in Fig. 8
to illustrate the belt drive arrangement for rotating the clamping
jaws 162 and 164 and the casing part 154. The sprocket 188 and the
cover 196 are both provided with suitable openings to provide for
the twisted wire pair to pass through the untwist unit 50.
Referring further to Figs. 3a and 8 a bracket 198 is attached
to one end of the frame 24 and comprises a support for a pair of
elongated arms 200 and 201 which are respectively pivotally mounted
on the bracket. The arms 200 and 201 are connected on one side
of their pivots to a linear cylinder type actuator 202 similar to
the actuator 126. The arms 200 and 201 include insulated clamping
pads 204 mounted on their lower ends as shown in Fig. 8. The arms
200 and 201 are operable to be moved together at their lower ends
to clamp a twisted wire pair which has been cut and stripped of a
predetermined length of insulation and moved into position for
clamping by the pads 204 as a result of movement of the un-twist
--10--
1~46744
unit 50 toward the arms, viewing Fig. 3a. A detector wire 210
is fastened to the arm 201 an~ is operable to close an electrical
circuit by engaging the arm 200 if a twisted wire pair is not in
position to be clamped by the pads 204 upon movement of the arms
toward each other by the actuator.
From the above description of the untwist unit 50 it may be
appreciated that a section of twisted wire pair disposed between
the gripping device 130 and the clamping jaws of the untwist unit
may be untwisted by rotating the casing part 154 a predetermined
amount in accordance with the number of twists in a wire pair be-
tween the gripping device 130 and the end of the clamping jaws
162 and 164 in the end portion 155 of the casin~ part 154. The
number of twists will change in accordance with distance between
the gripping device 130 and the end portion 155 of the casing
part and in accordance with the number of twists per unit of
length o the particular twisted wire pair being worked. Accord-
ingly, a suitable control signal to the stepping motor 194 may be
predetermined and used to operate the motor to untwist the wire
pair prior to cutting the wire and stripping the insulation from
the wire ends so formed.
The apparatus 22 is particularly well adapted to cut and strip
insulation from twisted wire pairs of relatively small wire diameter.
In particular, the embodiment disclosed herein is adapted to work
twisted wire pair in the range of 22 gage to 34 gage, American Wire
Gage system. The wire diameters for thls range of gages varies
from .025 in. (.643 mm) to .0063 in. (.160 mm). It may be appre-
ciated that positioning the wire for cutting the insulation only
without unintended partial or complete severance of the conductor
wire itself has been a problem in the art of conductor wire in-
sulation stripping. However, the wire positioning and insulationcutting blade mechanisms 42 and 44 of the present invention are
1~46744
adapted to solve this problem and operate in conjunction with the
above aescribed mechanisms of the apparatus 22 to provide i~proved
means for cutting and removing insulation from twisted wire pair.
After the wire pair has been untwisted in preparation for
cutting and stripping the insulation each wire must be guided
into a position whereby the insulation may be accurately cut with-
out cutting or scratching the metal conductor wire itself. This
is particularly critical in many electronic circuits where the
changes in electrical properties and the increased mechanical
stresses caused by cuts or scratches in the conductor wire cannot
be tolerated. Referring to Figs. 12 and 13 the mechanism 42 is
disclosed in detail. The mechanism 44 is substantially identical
in construction and operation and in the interest of conciseness
a detailed description of the mechanism 44 has been omitted. The
mechanism 42 includes two relatively thin platelike members 220
and 222 which are proportioned to be mountable in preselected pairs
of the grooves 108 and 110 of the support members 46 and 47 res-
pectively, as shown in Fig. 3a, in accordance with the desired
length of insulation to be cut and stripped. The members 220 and
222 are each engaged with one of the rods 118 to be moved recip-
rocably toward and away from each other. The member 220 is dis-
posed between wire positioning cam plates 224 and 226 and the
member 222 is similarly disposed between two cam plates 228 and
230. The cam plates 224 and 226 are held in assembled relationship
with the member 220 by flanged bushings 232 and 234 which are
mounted on the member 220 and are disposed in respective elongated
recesses 236 and 238 in the plates 224 and 226. The member 222,
in like manner, also includes flanged bushings 232 and 234 which
are disposed in elongated recesses 240 and 242 in the plates 228
and 230, respectively. The plates 224, 226, 228 and 230 are also
provided, respectively, with elongated openings 225, 227, 229 and
-12-
1~46744
231 to provide for m~vement of the actuating rods 118 with respect
to the plates.
Referring also to Figs. 14 and 15 the member 220 is connected
to the plate 224 by a coil spring 244 having its opposite ends
connected to the member 220 and the plate 224 as shown in Fig. 14.
The plate 228 and member 222 are similarly interconnected by a
second coil spring 244. The members 226 and 230 are similarly
connected to the plates 220 and 222, respectively, by additional
springs 244 as shown in Fig. 15. In Figs. 15 and 17 insulation
]0 cutting blade holders, to be described further herein, are shown
removed so as to illustrate the springs 244 interconnecting the
plates 226 and 230 with the members 220 and 222, respectively.
Suitable openings in the members 220 and 222 and the plates 224,
226, 228, and 230 are provided as shown for the springs 244 to be
located in the illustrated manner. The springs 244 provide for
the cam plate~ 224, 226, 228, and 230 to be yieldably biased into
engagement with the conductor wires of the wire pair in response
to movement of the members 220 and 222 toward each other.
Referring again to Figs. 12 and 13 the mechanism 42 also in-
cludes two opposed insulation cutting blade holders 250 and 252upon which are removably mounted insulation cutting blades 254.
As shown in Fig. 21 the blades 254 are provided with closely spaced
notches 256 and 258 in the edge 260 which is formed by the sloping
surface 262. The notches 256 and 258 form arcuate edges for cutting
the insulation of the wire of a wire pair. As shown in Figs. 19 and
20 when two blades 254 are brought into abu~ting relationship the
insulation of each wire is cut substantially all around the circum-
ference of the wire proper. The notches 256 and 258 are formed to
be slightly larger in their radii of curvature than the radius of
curvature of the particular size wire being worked by the apparatus
22. The blades 254 are formed to have a second set of insulation
-13-
~46744
cutting notches 262 and 264 which may be used as spares or be of
a different size for interchanging blades on the respective holders
250 and 252 when a larger or smaller gage wire is to be worked.
The proper positioning of the individual wires of the wire
pair in order to provide for accurate cutting of the insulation
only is partict~larly difficult for smaller gage wires. In the
present invention a plurality of coacting wire positioning cams
operate to overcome this difficulty. Referring to Fig. lS the
cam plates 224 and 228 are respectively formed to have cooperable
cam surfaces 264 and 266 which are inclined at approximately a
forty-five degree angle with respect to a vertical plane passing
through the axis of travel of the twisted wire pair. The cam
plates 226 and 230 are respectively formed to have cam surfaces
268 and 270 which are parallel and substantially vertically aligned.
Moreover, as shown in Fig. 20 the blade holders 250 and 252 are
formed to have respective right angle relieved portions 272 and
274 which, when the blades 254 are moved into abutting relationship
as shown, form a rectangular enclosure in which the insulated wire
is held tightly captive. As shown also in Fig. 20 the blade holder
250 is provided with a sloping wire engaging surface 276 which assist
the sloping cams 264 and 266 and the vertical cams 268 and 270 in
positioning the wire properly to have the insulation cut without
damage to the conductor wire itself.
Referring to Figs. 16 and 17 the members 220 and 222 are pro-
vided with respective projections 280 and 282 which are operable
to engage the cam plates 228 and 224 on respective surfaces 284
and 286, as shown in Fig. 17, when the members 220 and 222 are
moved toward each other. The projection 280 and 282 operate to
limit the movement of the cams 264 and 266 toward each other and
actuall~ cause the cam plates 224 and 228 to reverse their direction
of movement, that is away from each other as the cutting blades 254
are moved into abutting relationshLp. Relative movement in opposite
--1~--
lr~46744
directions between the cam plates 224 and 228 and the members 220
and 222, respectively, is possible by the elongated openings 225
and 229 and the springs 244 connecting the cam plates to the members.
The operation of the wire positioning cams and the insulation
cutting blades will now be desc~ibed, referring to Figs. 12 through
19. After the wire pair has been untwisted the separate insulated
wires 290 and 292, Fig. 13, may be disposed side by side directly
on the guide bar 102. The wires 290 and 292 may be disposed at
other positional relationships, one with respect to the other,
]0 also but to assure proper positioning of the wire the cams 264
and 266 and the cams 268 and 270 operate in sequence to align the
wires one over the other prior to engagement and cutting of the
insulation cover. When the cylinder actuators 120 and 126 are
energized to move the rods 118 as well as the members 220 and
15 222 toward each other the cam plates 224 and 228 will be moved
also by the bias of the springs 244 to cause the cams 264 and
266 to move toward each other and engage the wires 290 and 292
to position one wire 290 above the other wire 292 as shown in
Fig. 15.
Continued movement of the members 220 and 222 and the cam
plates 226 and 230 will cause the cams 268 and 270 to move into
engagement with the wires. As the cams 268 and 270 are pressed
into engagement with the wires 290 and 292 the projections 280
and 282 will, respectively, engage the surfaces 284 and 286 and
25 reverse the direction of movement of the cam plates 224 and 228.
Accordingly, as the cams 268 and 270 engage the wires to move them
into vertical alignment as shown in Fig. 17 the cams 264 and 266
have been moved away from each other to allow the wires to be
moved into position one over the other.
Referring to Fig. 15 the cam plates 226 and 230 are provided
with respective abutments 300 and 302 which come into engagement
with each other as the cams 268 and 270 reach the position shown
-15-
1~46744
in Fig. 17. The abutments 300 and 302 are located wlth respect
to the respective cam surfaces 268 and 270 in such a way that
when the abutments engage each other the slot formed~between the
cams 268 and 270 is wide enough to permit easy vertical movement
of the wires 290 and 292 with the wires aligned one on top of
the other. Since the wires 290 and 292 will likely not be per-
fectly positioned vertically to be correctly engaged by the notches
in the insulation cutting blades continued movement of the rods 118
will cause the blade holders 250 and 252 to continue their movement
toward each other whereby the sloping surface 276 will engage the
lower wire 292 and move the wires 290 and 292 vertically until they
abut the overhanging projection 306 on the holder 252. The holders
250 and 252 will also be moving to the closed position shown in
Figs. 19 and 20 as the blades commence and then complete their
cutting action through the insulation with the enclosure formed
by the recesses 272 and 274 providing for final and precise align-
ment of the wires. As the insulation is being cut by the action
of the mechanisms 42 and 44 the wire cutting blades 310 and 312,
Fig. 9, move together to sever the wire pair thereby forming a
twisted wire pair of predetermined length. The blade holders 250
and 252 will then remain in their closed positions for both of the
mechanisms 42 and 44 whereupon the gripping device 130 will be
opened to release the clamping action on the wire pair 30. The
clamp 36 will remain in the closed and wire gripping position as
will the clamping jaws 162 and 164 of the untwist unit S0. The
actuators 28 and 56 will be energized to move the clamp 36 and
the untwist unit 50 away from each other to strip the insulation
from the wire ends formed during the wire and insulation cutting
operation. As the guide bar 102 moves with the clamp 36 the
stripped insulation will drop into the drawer 48 through the
opening 320 in the frame 24, shown in Fig. 9.
-16-
1~467~4
Referring to Fig. 3a and Fig. 18 the apparatus 22 is provided
with a plurality of wire guide members 322 which may be inserted
as needed between each blade mechanism 42 and 44 and the wire
cutting blade mechanism 4~ to form substantially uninterrupted
guiding of the wire pair as it is fed to the untwist unit 50. The
wire guide 322 as shown in Fig. 18 comprises a substantially flat
plate member having a funnel shaped opening 324. Pins 326 and 328
on the upper and lower edges of the guide member 322 provide for
positioning the guide member in the grooves 10~ and 110 in the
respective support members 46 and 47.
Fig. 22 illustrates a length of twisted wire pair 31 having
been prepared by the apparatus of the present invention. Adjacent
end portions 291 and 293 of the respective wires 290 and 292 have
been untwisted and have had predetermined lengths of insulation
cut and stripped therefrom. As shown in the drawing Fig. 22 the
opposite set of adjacent end portions 295 and 297 also have pre-
determined lengths of insulation removed therefrom.
The apparatus 22 may be adapted to cut the insulation from
only one set of adjacent ends of a wire pair if so desired. For
example, by removing the insulation cutting blade mechanism 42 or
44 from the apparatus 22 the insulation will be cut and stripped
from the ends of each wire at one end only of the twisted wire
pair. Moreover, by removing the blade mechanism 42 and placing
the gripping device 130 at a desired position with respect to the
wire cutting mechanism 40 the adjacent end portions of the wire
of the wire pair which do not have insulation cut and stripped
therefrom may be untwisted over a predetermined length.
The apparatus 22 may be operated by a control circuit including
suitable signal generating devices which cooperate to operate the
motors 90 and 194 and to operate suitable pressure fluid valves
for controlling the flow of pressure fluid to and from the various
-17-
1~46744
pressure fluid actuators on the apparatus. The controls may include
circuit devices which will allow the preselection of the amount of
rotation of the motor 90 whereby a preselected length of wire-pair
may be fed through the apparatus 22 into position for cutting and
stripping of the insulation and cutting of the prepared wire pair
to the preselected length. Similar control devices, well known to
those skilled in the art of electrical controls, may be used to
permit preselection of the amount of rotation of the motor 194 to
control the amount of untwisting of the wire pair.
It may be appreciated that the apparatus of the present inven-
tion may be suitably interfaced with various types of circuit wiring
machinery and be automatically controlled by suitable numerical
control equipment to produce, successively, a predetermined number
of twisted wire pairs of various predetermined lengths. Moreover,
]5 by changing the positions of the mechanisms 42 and 44 in the support
members 46 and 47 and with respect to the wire cutting mechanism 40
various lengths of insulation may be stripped-from the wire end.
Additionally, the mechanisms 42 and 44 may be easily interchanged
with similar mechanisms proportioned for different wire and in-
sulation diameters.
An operating cycle of the apparatus 22 will now be describedassuming that a twisted wire pair has previously been cut and
stripped so that the leading end of a wire pair has been prepared
by the untwisting and stripping of the insulation from the indi-
vidual wires. The tip of the leading end of the wire pair to beformed would be substantially aligned with the cutting blades 310
and 312 with respect to path of travel of the wire pair through
the apparatus. The mechanisms 40, 42, and 44 would be returned
to their retracted or open positions as shown in Figs. 9 and 13.
Moreover, the clamp 36 and the gripping device 130 would be in
the jaws retracted or open position as would the clamping jaws
162 and 164 of the untwist unit 50. The actuators 28 and 56
-18-
10467*~
would be in the position shown in Figs. 1 through 3a and the
arms 200 and 201 would be in the open position shown in Fig. 8.
A cycle of operation of the apparatus 22 is commenced by
energizing the motor 90 with a suitable repeating pulse signal
until the motor has rotated the predetermined amount to linearly
feed a predetermined length of twisted wire pair past the mechanism
40. The pulse signal to the motor 90 is counted by a suitable
signal counting device until a predetermined count is reached
whereby the motor 90 is deenergized. After a short time delay
which commences with deenergization of the wire feed motor 90
suitable valves are actuated by the control circuit to supply
pressure fluid for actuating the clamp 36, gripping device 130,
and the clamping jaws of the untwist unit 50 to clamp the twisted
wire pair hy these elements. At the same time pressure fluid at
a regulated low pressure is supplied to the actuator 56 to tend
to move the untwist unit 50 to the right, viewing Figs. 1, 2, or
3a. Thi-s action places the twisted wire pair in tension-between
the gripping device 130 and the untwist unit 50 to provide for
keeping the individual wires from becoming slack as they are
untwisted by the untwist unit.
After a suitable time delay to provide for actuation of the
jaws of the clamp 36, gripping device 130, and untwist unit 50,
and the tensioning of the wire pair, a repeating pulse signal is
delivered to energize the motor 194 to untwist the wire pair
between the untwist unit and the gripping device. A suitable
signal counting device counts the signal pulses and generates a
signal to stop the motor 194 after a predetermined number of pulses
in accordance with the desired number of revolutions or portions
thereof of the casing part 154.
When the motor 194 is deenergized suitable valve means are
actuated to conduct pressure fluid to the actuators 120 and 126
to cause the mechanisms 42 and 44 to be actuated as described
--19--
1046744
hereinbefore to cut the insulation of the trailing end of the
wire pair being formed and the leading end of the next to be
formed wire pair of predetermined length. Simultaneously, the
mechanism 40 is also actuated to cut the wire pair thereby forming
a predetermined length of twisted wire pair. As the arms 112 and
114 complete their movement to the position wherein all cutting
blades are closed a proximity switch is actuated by one of the arms
to cause a suitable solenoid valve to supply pressure fluid to
release the gripping action of the jaws 148 of the gripping device
]o 130. The closure of the above mentioned proximity switch also
generates a time delayed signal to suitable valving means to
supply pressure fluid to the actuators 28 and 56 at sufficient
pressure to move the feed mechanism 26, and clamp 36 to the left,
viewing Figs. 1 through 3a, and, respectively, the untwist unit
50 to the right, viewing the same drawing figures. The afore-
mentioned action, with the blades of the mechanisms 42 and 44
in abutting relationship, will cause the insulation to be stripped
from the ends of the wires disposed between the mechanisms 42 and
44 as these wire ends are pulled away.
After a suitable time delay to allow the insulation stripping
action to be completed pressure fluid is vented from the clamp 36
and untwist unit 50 to release the clamping action on the wires.
At the same time the actuators 120 and 126 are energized to open
the blade mechanisms 40, 42, and 44 and the actuator 202 is
25 energized to close the arms 200 and 201 to grip the wire pair just
formed, and which is projecting beyond the twist unit 50 to the
right viewing Fig. 3a. A stream of pressure air may be directed
to blow the stripped insulation through the opening 320 into the
drawer 48 as the blade mechanisms 42 and 44 are being opened.
A time delay is al50 initiated beginning with the signals
which energize the actuators 120, 126 and 202 to ailow the functions
.
-20-
~04~744
performed by these actuators to occur before a control signal is
then generated to shut of f the stream of insulation ejecting air
and the actuators 28 and 56 are vented on one side of their respec-
tive pistons and pressurized on the opposite sides to cause the
actuators to move the feed mechanism 26, clamp 36 and untwist unit
50 back to the positions shown in drawing Figs. 1, 2, 3, and 3a.
With the arms 200 and 201 in the closed or wire clamping position
the twisted wire pair just formed will be withdrawn from the untwist
unit 50. The leading end of the twisted wire pair 30 will be re-
positioned adjacent to the cutting blade mechanism 40. Even thoughthe clamp 36 has been released after the insulation stripping action
the belts 86, in firm engagement with the wire pair 30, will prevent
movement of the wire pair with respect to the feed mechanism 26 and
clamp 36 until the motor 90 is energized.
As the actuators 28 and 56 complete their movement to reposition
the respective associated mechanisms a suitable limit switch on the
apparatus 22 may be engaged by the bracket 68, for example, to there-
by cause a signal to be initiated to operate suitable valve means to
open the arms 200 and 201. The twisted wire pair just formed will
thereby be released to drop into the tray 58. After a short time
delay to allow the arms 200 and 201 to open the apparatus is ready
for the next cycle of operation which may, of course, be automaticall
commenced by a suitable signal initiated at the end of the afore-
mentioned time delay period.
2~
