GB2193128A

GB2193128A - Apparatus for twisting wires at the end of a conductor into a strand

Info

Publication number: GB2193128A
Application number: GB08618393A
Authority: GB
Inventors: Evgeny Pavlovich Ryzhov
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-01-03
Filing date: 1986-07-29
Publication date: 1988-02-03
Also published as: DE3600082C2; GB8618393D0; CH668509A5; DE3600082A1

Abstract

An apparatus for twisting unbraided filaments (8) of the shield at the end of a conductor (9) into a strand comprises a base (1) on which is mounted for reciprocation a carriage (3) supporting a rotatable bushing (5) to which is secured a device for engaging the filaments (8) which consists of two plates (10, 11) secured to pivotable levers (12, 13) each having one end cooperating with a plunger (15) mounted in the bushing (5) for reciprocation so as to bring the plates (10, 11) closer to each other. Each plate has a recess (33) and a projection (34) which faces towards the other plate and which extends opposite to its recess (33) and at an angle with respect to this plate such that when the plates are brought closer to each other, the projection (34) of one of them is received in the recess (33) of the other to define a space (35) between the plates and the projections for receiving the bunch of unbraided filaments (8). <IMAGE>

Description

SPECIFICATION Twisting wires at the end of a conductor into a strand The invention relates to the production equipment for prewiring preparation of conductors, and in particular, it deals with apparatuses for twisting wires at the end of a conductor into a strand.

The invention may be used in the radio, electrical and instrumentation engineering for prewiring preparation of wiring conductors.

The prewiring preparation of wiring conductors consists of a number of production steps including cutting a conductor to measure, stripping the ends of the conductor of shielding braid, twisting into a strand and tinning the unbraided filaments of the shield at the ends of the conductor, stripping insulation at the ends of the conductor, imparting additional twist to the stranded wire at the ends of the conductor and tinning the ends of the conductor.

At present, the operation of twisting wires at the ends of a conductor into a strand, in cluding twisting of the unbraided filaments of the shield, is effected by means of various devices, including manual devices, the employment of which cannot ensure high productivity and quality of twisting.

Known in the art is an apparatus for twist ing wires at the end of a conductor into a strand (cf. USSR Inventor's Certificate No.

943950, Cl. H 02 G 1/12, 1981), comprising a base on which is there is mounted for reci procations a carriage supporting a rotatable bushing on which is secured a device for en gaging wires at the end of a conductor com prising a paior of plates having their ends co operating with a plunger mounted for recipro cations in the bushing so as to bring the plates closer to each other.

The carriage is operatively connected, via a roller, to a cam mounted on a drive shaft. A pulley is secured to the bushing and is opera tively connected to a rotary drive by means of a belt transmission.

In the initial position, the carriage and plun ger are in the lowermost position, and the plates are spaced apart. When the drive is energized, the shaft carrying the cam starts rotating to actuate the belt transmission. The cam engages the roller so that the carriage starts moving upwards along a guide member, and rotation is transmitted through the belt -transmission to the pulley, bushing and device for engaging wires at the end of a conductor.

At the same time, the plunger moves up to cooperate with the device for engaging wires so that the plates are brought closer to each other thus approaching the wires to be twisted into a strand and engaging them. The carriage and plunger are in the upmost posi tion, and the device for engaging wires permanently rotates thus twisting the wires into a strand.

Subsequently, during further cooperation of the cam with the roller, the carriage is lowered down. The plunger also moves down and is disengaged from the device for engaging the wires, the plates are moved apart, and the apparatus returns to the initial position.

The abovedescribed apparatus is mainly designed for stripping and twisting the ends of wiring conductors, and namely, for stripping insulation with simultaneous additional twisting of the stranded wire.

The abovedescribed apparatus may also be used for twisting into a strand unbraided filaments of the shield at the end of a conductor, but the desired quality of twisting cannot be achieved. This is explained by the fact that filaments of the shield unbraided at the end of a conductor fed to the apparatus after the ends of the conductor have been stripped of the shielding braid are bent down in the form of a fan-like bunch, and the plates would flattent the bunch wne they are brought closer to each other. The outer filaments would move outwards, away from the center of the bunch, and will remain outside the twisting zone thus making it necessary to afterwork the conductor.

Therefore, the abovedescribed apparatus cannot ensure the desired quality of prewiring preparation of wiring conductors, namely twisting of wires at the ends of a conductor and has a low productivity.

It is an object of the invention to improve quality of twisting into cord filaments of the shielding braid unbraided at the end of a conductor and to improve productivity of an apparatus.

This object is accomplished by that in an apparatus for twisting wires at the end of a conductor into a strand, comprising a base on which is there is mounted for reciprocations a carriage supporting a rotatable bushing to which is secured a device for engaging wires at the end of a conductor comprising a pair of plates, the ends of the plates cooperating with a plunger mounted in the bushing for reciprocations so as to bring the plates closer to each other, according to the invention, each plate has a recess and a projection facing towards the other plate and extending opposite to its recess at an angle with respect to the plate such that when the plates are brought closer to each other, the projection of one of them is received in the recess of the other so as to define a space between the plates.

The plates preferably have a device for adjusting the space therebetween which is defined upon bringing them closer to each other.

The apparatus according to the invention ensures high-quality twisting of all filaments of unbraided shield at the end of the conductor into a strand. Therefore, time losses associ ated with afterworking of poorly twisted un braided filaments of the shild at the end of the conductor are eliminated thus bringing about an improved productivity of the apparatus as a whole.

The invention will now be described with reference to the accompanying drawings which show: Figure 1 is a general view of an apparatus according to the invention with a carriage in longitudinal section; Figure 2 is a perspective view of a device for engaging wires at the end of a conductor according to the invention; Figure 3 shows a plan view of plates in a device for engaging wires at the end of a conductor in the position when they are brought closer to each other according to the invention.

An apparatus for twisting wires at the end of a conductor forms part of a machine for a comprehensive pre-wiring preparation to conductor ends. The apparatus is designed for twisting unbraided filaments of the shield at the end of a conductor into a strand.

A conductor is fed to an apparatus for twisting wires at the end of the conductor into a strand after unbraiding of the shield at the end of the conductor, as a result of which operation the unbraided filaments of the shield are in the farm of a downwardly bent bunch, the end of the conductor stripped of the shield being bent upwards.

The- twisting apparatus comprises a base 1 (Fig. 1) to which is rigidly secured a guide member 2 on which there is mounted for reciprocations a carriage 3 moving along the guide member 2. Journalled in bearings 4 on the carriage 3 is a bushing 5 which is connected, by means of a belt transmission 6, with a drive (not shown in the drawing).

The bushing 5 has cantilever projections 7 supporting a device for engaging wires at the end of a conductor, namely unbraided filaments 8 of the shield of a conductor 9, which comprises a pair of plates 10,11 which in this embodiment of the apparatus are secured to the ends of double-arm levers 12 and 13 pivotally secured to á pivot pin 14.

A plunger 75 is mounted inside the bushing 5 for reciprocations coaxially therewith and has the end thereof facing towards the levers 12 and 13 which is wedge-shaped.

The housing 1 supports a lever 16, a stop 17 and a drive 18 having a shaft 19 carrying cams 20 and 21. A roller 22 is provided on the carriage 3 for engaging the cam 20, as well as levers 23 and 24. The lever 23 is connected to the carriage by means of a spring 25 and has at one end a projection 26, the other end having a spring-biased pusher 27. The lever 24 is connected to the carriage 3 by means of a spring 28, and the carriage is connected to the housing 1 by means of a spring 29.

The plates 10 and 11 are provided with a device 30 for adjusting a space therebetween upon bringing them closer to each other, which, in this particular embodiment, comprises an adjusting screw 31 mounted on the plate 10 and a stop 32 located on the opposite plate 11.

In the initial position of the apparatus shown in Fig. 1, the plunger 15 and pusher 27 are in the lowermost position, and the plates 10,11 are spaced apart. Each plate 10 and 11 has a recess 33 (Fig. 2) and a projection 34 facing towards the other plate 10, 11 and extending opposite to the recess 33 thereof and at an angle to the plate 10, 11 such that when the plates 10 and 11 are brought closer to each other, the projection 34 of the plate 10 is received in the recess of the plate 11 so as to define a space 35 between the plates 10, 11 (Fig. 3) for receiving the bunch of the unbraided filaments 8 of the shield of the conductor 9. The angle at which the recess extends with respect to the plates 10, 11 should be other than 90" and depends on the diameter of the conductor 9.

Operation of the Invention When the drive 18 is turned on, the shaft 19 carrying the cams 20 and 21 starts rotating and, at the same time, the belt transmission 6 is actuated to rotate the bushing 5 and the levers 12, 13 carrying the plate 10, 11.

As a result of engagement of the cam 20 with the roller 22, the carriage 3 starts moving up along the guide member 2.

When the carriage 3 reaches the upper position, the cam 21 engages the lever 16 which will engage the lever 23.

The lever 23 is caused to turn about its pivot pin to raise the spring-niased pusher 27 which will engage the plunger 15 to push it up. The plunger 1 5 will be raised to cooperate with the ends of the levers 12,13 so as move their ends apart and so that the other ends of the levers 12,13 carrying the plates 10,11 will start moving towards each other to engage the unbraided filaments 8 of the shield at the end of the conductor 9. The projections 34 (Fig. 2) of the plates 10,11 are received in the recesses 33 of the plates 10, 11 so as to define the space 35 (Fig. 3). The amount of this space 35 is adjusted by means of the screw 31 (Fig. 2) and stop 32 depending on the diameter of the unbraided filaments 8 of the shield of the conductor 9.

Owing to the provision in each plate 10,11 of the recess 33 and projection 34, the bunch of filaments 8 is disposed within a closed space defined by the plates 10, 11 and projections 34. The twisting of the bunch of filaments 8 is started at the base of the bunch, and all filaments 8 remain within the twisting zone so that the bunch 8 is not subjected to any flattening action.

At the moment when the plunger 15 reaches its upmost position, the lever 24 is caused to engage with one end thereof the projection 26 under the action of the spring 28. The pusher 27 bears against the plunger 15 which will engage the levers 12,13 with its wedge-shaped end so as to retain the plates 10,11.

During further cooperation of the cam 20 with the roller 22, and also under the action of the spring 29, the carriage 3 starts moving down along the guide member 2. The rotating bushing 5 carrying the levers 12, 13 and the plates 10, 11 brought closer to each other is caused to move down thus twisting the bunch of the filaments 8 along the whole extent thereof.

As a result of the downward movement of the carriage 3, the free end of the lever 24 engages the stop 17 thereby disengaging the other end of the lever 24 from the projection 26. Under the action of the spring 25, the lever 23 is turned about its pivot pin, the pusher 27 and the plunger 15 are lowered, and the plunger 15 is disengaged from the levers 12,13.

As the bushing 5 with the levers 12,13 continues to rotate, the ends of the levers 12, 13 carrying the plates 10, 11 will move apart under the action of centrifugal forces so as to release the unbraided filaments 8 of the shield of the conductor 9 which are now twisted into a strand.

The apparatus is now in the initial position and is ready for handling the next bunch of wires.

Therefore, the filaments of the shielding braid, that have been unbraided at the end of the conductor, are twisted into cord, and the conductor is prepared for a next processing stage of the prewiring preparation of the conductor.

Claims

1. An apparatus for twisting wires at the end of a conductor into a strand, wherein a carriage is mounted for reciprocations on a base; a bushing is rotatably mounted on the carriage; a plunger is mounted in the bushing for reciprocations; a device for engaging wires at the end of a conductor is secured to the bushing and comprises a pair of plates, each having one end cooperating with the plunger so as to bring the plates closer to each other, each plate having a recess and a projection which faces towards the other plate and extends opposite to its recess at an angle with respect to this plate such that when the plates are brought closer to each other, the projection of one of them is received in the recess of the other to define a space between the plates.

2. An apparatus for twisting wires at the end of a conductor into a strand according to claim 1, in which that the plates have a device for adjusting the space therebetween which is defined upon bringing them closer to each other.

3. An apparatus for twisting wires at the end of a conductor into a strand substantially as hereinabove described with reference to, and as shown in the accompanying drawings.