FR2618953A1 - Methods and devices for automatically inserting electrical connection components into cavities or onto conducting terminals - Google Patents

Abstract

The subject of the invention is methods and devices for automatically inserting electrical connection components into cavities or onto conducting terminals. A device according to the invention includes a gripper 7a, 7b actuated by actuators (jacks) 8a, 8b, which is placed at the end of a rod 9 which slides in a tube 3 integral with a movable support which enables the gripper to move along its axis zz' in order to insert an electrical connection component 2, crimped at the end of a wire 5, into a cavity 1a or onto a conducting terminal. The tube 3 includes a shoulder 3a. The rod 9 includes two collars 9a, 9b. Two microswitches 12, 13, carried by the tube, detect the relative movements of an enlarged portion 9c inside the tube 3. One application is the automatic connection of the electrical wires leaving a wiring machine to insulating cases or onto terminals.

Description

DESCRIPTION
Methods and devices for automatically inserting electrical connection parts into cells or onto conductive terminals.

 The present invention relates to methods and devices for automatically inserting electrical connection parts into cells of insulating shells or onto conductive terminals.

 Patent application FR 86 16777, filed on November 28, 1986 describes methods and devices for automatically inserting into insulating case cells or onto conductive terminals, connection pieces which are crimped onto the ends of a batch of conductor wires coming out of an automatic wiring machine.

 These automatic insertion or insertion operations require precise checks to prevent the automatic machine from being blocked following incorrect insertion and to check that the insertion has been correctly carried out.

 When inserting a connection piece automatically into a socket or on a conductive terminal, you must push the connection piece with sufficient force, but you must check that you are not applying too high a force to the connection piece which could bend or damage it. Such a defect appears in particular when the cell or the conductive terminal intended to receive the connection part is not perfectly aligned with the latter.

 I1 also appears in the case where the dimensions of the connection piece or of the cell or of the conductive terminal do not correspond to the tolerances provided.

 The connection pieces generally carry a flexible locking tab which engages in a housing hollowed out in the wall of a cell or on a conductive terminal when the connection piece is in place and which prevent the latter from moving back in the way sting of a hook or harpoon.

 When a connection piece has been inserted or inserted, it must be checked that the locking has been carried out. At the same time it can be verified that the crimping of the connection piece on the conductive wire resists a given tensile force.

 An objective of the invention is to provide means making it possible to automatically insert connection parts into cells or to automatically plug them into conductive terminals by automatically carrying out the checks which make it possible to avoid pressing on the connection parts. thrust forces exceeding the resistance limits thereof.

 Another objective of the invention is to provide means which make it possible to automatically check that the connection pieces are properly locked by exerting a tensile force on them while limiting this force to a value such that there is no risk do not tear off the connecting parts which are securely locked.

 A method according to the invention is of the known type in which each conductive wire is grasped immediately behind a connection piece crimped on one end of it by means of a clamp carried by a mobile support that the one moves parallel to its axis towards a cell or towards a conductive terminal placed in alignment with this axis.

 The objectives of the invention are achieved by a process in which a mechanical connection means is inserted between said movable support and said clamp capable of transmitting to said clamp a thrust forward parallel to said axis and during the insertion of a connecting piece in a cell or on a conductive tab, said thrust is measured, it is compared to a threshold and, if this threshold is exceeded, the advance of said carriage or of said articulated arm is automatically stopped and an alarm is triggered.

 Advantageously, a second mechanical connection means capable of transmitting a rearward pull to said clamp parallel to said axis is inserted between said movable support and said clamp, and after having inserted a connection piece in a socket or on a conductive tab, moves said movable support back without loosening said clamp, the tensile force is measured and compared with a threshold and if this threshold is reached, said clamps are loosened and the return stroke of said movable support is continued and, if this threshold is not not reached, an alarm is triggered indicating a locking fault or a crimping fault in said connection piece.

 According to a particular embodiment, the mechanical connection means are elastic connections placed between a tube integral with said mobile support and a rod carrying said clamp, the displacement of said rod in said tube is measured when said mobile support is moved parallel to said axis and when the mobile support advances to engage a connection piece in a cell or on a conductive tab, we compare said relative displacement with a first threshold and if this is exceeded we automatically stop said mobile support and we trigger an alarm and when said mobile support moves back without the clamp being loosened, said displacement relative to a second threshold is compared and, if this second threshold is reached, the clamp is automatically released and said mobile support continues its return stroke and if at the end of said return stroke said second threshold has not been reached, an alarm is triggered.

 Advantageously, the elastic connections consist of two springs placed between a shoulder of said tube and two flanges carried by said rod and the relative displacements of said rod in said tube are measured by means of two microswitches placed on either side of the position. normal of a bulge of said rod.

 A device according to the invention is of the type comprising a clamp which grasps each wire immediately behind a connection piece and a movable support making it possible to move said clamp relative to said boxes in three trirectangular directions, one of which is parallel to the clamp axis in order to bring cells or conductive terminals in alignment with the clamp and to insert in each of these a connection piece.

The objectives of the invention are achieved by means of a device in which each clamp has two jaws placed at the front end of a rod which slides in a coaxial tube which is integral with said movable support and said device comprises a first connection mechanical capable of transmitting a thrust forwards between said tube and said rod and it further comprises means for comparing said thrust with a threshold and for automatically stopping the forward movement of said movable support and
trigger an alarm when this threshold is exceeded.

Advantageously, a device according to the invention comprises a second mechanical connection capable of transmitting rearward traction between said tube and said rod and means for comparing said tensile force with a threshold when said support is moved back without loosening said clamp. , means to loosen automatically
said clamp when this threshold is reached and means for triggering an alarm if this threshold is not reached during the return stroke
of said mobile support.

According to a preferred embodiment, the tube has an internal shoulder, said rod has two flanges placed
on either side of said shoulder and said device comprises two springs placed respectively between said shoulder and each
said flanges and means for comparing the relative displacements of said rod inside said tube with thresholds.

Advantageously, the rod has a bulge and said
tube carries two microswitches placed on either side of the position of said bulge when the two springs are not compressed.

The invention results in the possibility of automatically inserting connection pieces crimped onto electrical wires.
in cells to make connectors or on conductive terminals to make interconnections between electrical devices avoiding most interruptions of operation
due to connecting parts which come up against an obstacle and which are bent or damaged by a push exceeding their resistance.

Another result of the invention is the possibility of testing
the correct locking of a connection piece as soon as it has been inserted into a cell or plugged into a terminal and at the same time testing the solidity of the crimping of the connection piece on the wire by exerting traction on this wire without the intensity of the pulling force exceeding a dangerous threshold because the pliers
open automatically when a threshold is reached which is below the dangerous threshold.

 Another advantage of the devices according to the invention which comprise an elastic connection, in particular a spring which transmits a thrust to the rod carrying the clamp, lies in the fact that this elastic connection changes in length by compressing and allows a difference in stroke between the clamp and the movable support so that the stroke of the movable support can be adjusted so that it has a slight excess which corresponds to the maximum tolerances and in cases where the maximum tolerance is not reached, the compression the spring automatically provides compensation and prevents the clamp from being subjected to a high stress when it abuts on the walls of the cell.

 The following description refers to the appended drawings which represent without any limiting nature an embodiment of a device according to the invention.

 Figure 1 is a schematic perspective view of a device according to the invention.

 Figure 2 is an axial longitudinal section of Figure 1.

 FIG. 1 represents an overall view of a device according to the invention which is placed at the outlet of an automatic wiring machine which delivers batches of wires cut according to determined lengths and equipped with connection pieces crimped on their extremities.

 The device according to the invention is intended to insert the connection pieces one by one into each of the cells 1a of an insulating boot 1 in order to form connectors or on connection terminals.

 The device according to the invention comprises a clamp 3 of axis zz 'which grips each section of wire 5 immediately behind a connection piece 2 crimped on the end of the wire. The clamp 3 is mounted on a mobile support, for example on a carriage or on an articulated arm 4 which moves the clamp parallel to the axis zz '. One or more insulating boot shells 1 are mounted on a mobile table 6 which moves them parallel to two perpendicular axes xx 'and yy' situated in the plane of the table which is perpendicular to the axis zz '. Of course, the movements are relative and the same result can be achieved by means of a clamp 3 mounted on an articulated arm which moves it along three trirectangular axes, one of which is parallel to the axis zz 'of the clamp.

 The movements of the carriage 4 and the table 6 are controlled by servo motors 4a, 6a, controlled by a microprocessor 14.

This is programmed to bring successively into the alignment of the clamp each cell la in which we must engage a connecting piece 2 and then to move the clamp 3 along the axis zz 'to insert the connecting piece in the cell until this locking tab carried by the connection clamp is engaged in a housing hollowed out in a wall of the cell, then to loosen the clamp, bring it back, grasp a new wire 5 and start a new cycle.

 For these operations of automatic insertion of the connection pieces 2 into cells la or on conductive terminals to take place without incident, the clamp 2 must be well aligned with the cell or with the terminal which must receive it otherwise the connecting parts come up against an obstacle, they are bent or deformed and the entire automatic machine is blocked.

 A device according to the invention makes it possible to trigger an alarm when the connection piece encounters an obstacle and to interrupt the operation of the machine before the connection piece, which abuts on an obstacle, is deformed.

 It also makes it possible to verify that the connection piece is properly locked.

 2 shows a section of Figure 1 passing through the axis zz 'of the clamp.

 We find in this figure a cell placed in alignment with the axis zz 'and we see that one of the walls of the cell carries a cutout lb in which must come to hang a locking tab 2a fixed on the part connection 2.

 The connecting piece 2 is for example a plug with rolled edges which comprises a crimp 2b on the stripped conductive wire and a crimp 2c on the insulating sheath of the wire 5. The clamp comprises a hollow tube 3 of axis zz 'which is moved axially by a carriage or by an articulated arm. The word tube is used in a general sense to designate any cylindrical tube of round, square or other section or a sheath or guide rods circumscribed to a tubular contour. It comprises at the front two jaws 7a, 7b which are situated in planes perpendicular to the plane of the figure and which are clamped against the conductive wire 5, immediately behind the connection piece 2 by two small jacks 8a, 8b controlled by a microprocessor 14.

 The two jaws 7a, 7b and the two micro-jacks 8a, 8b are fixed to the end of the two arms of a fork between which the wire 5 passes. This fork is carried by a rod 9, which is coaxial with the tube 3 in which it can slide.

 The rod 9 carries two flanges 9a and 9b located inside the tube 3, on either side of a peripheral shoulder 3a extending inside said tube. The rod 9 is locked in rotation relative to the tube 3, for example by lugs carried by the flanges which slide in longitudinal grooves of the tube.

 A first spring 11 is placed between the shoulder 3a and the front flange 9a. A second spring 10, less rigid, is placed between the shoulder 3a and the rear flange 9b.

 The rear end of the rod 9 has a flange or a cylindrical bulge 9c which slides against the internal walls of the tube 3 and guides the rod inside the tube. The tube 3 carries two microswitches 12 and 13 each equipped with a roller 12a and 13a which projects inside the tube 3.

 These two rollers 12a and 13a are located respectively at the rear and at the front of the position of the bulge 9c when the two springs are not constrained and they are actuated by the bulge 9c which acts as a cam when the stress of the spring 10 or 12 exceeds a determined threshold. The microswitches 12 and 13 are connected to the microprocessor 14.

The operation is as follows
The microprocessor 14 controls the advance parallel to the axis zzl of the carriage or of the articulated arm carrying the clamp 3, this advance having a determined length which corresponds to the normal length of insertion of the connection piece 2 in the alveolus slightly increased to take account of clearances and tolerances.

 If the cell 1a is well aligned with the clamp, the connection piece meets no resistance, the spring 11 transmits the movement between the shoulder 3a and the collar 9a keeps its normal length.

 If the connecting piece encounters resistance to advancement, the spring 11 compresses, which causes a relative movement of the cam 9c towards the rear end of the tube 3. The spring 11 is chosen so that the cam 9c reaches the roller 12a before the connection piece risks being bent or deformed.

The microprocessor which receives the signal delivered by the microprocessor 12 automatically stops the advancement of the carriage or of the articulated arm and triggers an alarm.

 The microprocessor 12 automatically stops the advancement of the clamp in the case where the connection piece cannot penetrate into the cell due to a misalignment or as a result of the relative dimensions of the connection piece with respect to those of the socket.

 To obtain the engagement of the locking tab 2a in the housing lb, the flexible tongue must be sufficiently advanced to disengage and penetrate into the housing lb.

The tolerances in the dimensions of the connection pieces and the cells require a safety margin. This is why the advance travel of the carriage is increased to take account of the maximum sum of tolerances on the dimensions of the connection parts, of the tongues and of the cells.

 I1 follows that the stroke of the carriage is often too long and that the connecting piece abuts in the bottom of the cell la. In this case, the spring 11 compresses, which reduces the stroke of the clamp all the more. The spring 11 therefore also fulfills a tolerance compensation function and is used to absorb the additional travel of the carriage in the case where the tolerances are less than the maximum sum provided.

 Once the carriage 4 has reached the end of the travel stroke and the connection piece 2 has been inserted into the socket la or on a tongue, the microprocessor controls the return of the carriage or of the articulated arm carrying the tube 3.

The recoil movement of the tube 3 is transmitted to the rod 9 by the spring 10 placed between the shoulder 3a and the flange 9b.

 At this moment the jacks 8a, 8b still hold the jaws 7a, 7b tight on the wire and if the locking tab 2a is properly locked in the housing lb, the spring 10 is compressed and the cam 9c moves inside of the tube 3 with a relative forward movement and it comes into contact with the roller 13a which actuates the microswitch 13 which sends a signal to the microprocessor 14, which immediately actuates the jacks 8a, 8b to open the clamp and release the wire and the carriage 4 normally continue its recoil movement.

 If the microswitch 13 does not emit any signal during the reversing of the carriage, this means that the connection piece 2 is not locked in the socket la or on the terminal or that the crimping of the connection piece on the wire did not hold. In this case, the microprocessor interrupts the operating cycle and triggers an alarm indicating that there is a fault.

 The tensile test on the wire must be carried out with a tensile force significantly lower than the thrust necessary to insert a connection piece in a cell or on a tongue and the spring 10 is a much weaker spring than the spring 11.

 FIG. 2 represents an embodiment in which the relative displacements of the rod 9 inside the sheath 3 are detected analogically by two micro-switches acting in all or nothing mode when these displacements exceed a threshold.

 It is specified that the displacements of the rod 9 can also be measured by a displacement sensor which transmits digital values to the microprocessor 14 which compares them to two thresholds, one positive and the other negative.

 The connection between the rod 9 and the sheath 3 constituted by two springs can be replaced by any other equivalent elastic connection means, for example by elastic pads or by gaseous mattresses compressed between the cylinder 3 and two pistons fixed on the rod 9.

 The embodiment shown in FIG. 2 is a preferred embodiment in which the spring 11 makes it possible to obtain a difference in travel between the sheath 3 and the rod 9 which compensates for the tolerances.

 The relative displacements of the rod correspond to variations in length of the springs which themselves correspond to forces.

The springs can be replaced by strain gauges
mechanical placed on links / between the sheath 3 and the rod 9 which deliver signals proportional to the forces transmitted by the sheath 3 to the rod 9. These signals are sampled by the microprocessor which is programmed to compare them with two thresholds.

Claims (9)

 1. Method for inserting a connection piece (2) crimped at the end of a conductive wire (5) in a cell (la) or on a conductive terminal of the type in which said wire (5) is grasped immediately at 'rear of said connecting piece (2) by means of a clamp (7a, 7b) carried by a mobile support (4) which is moved parallel to its axis (zz') towards a cell (la) or a conductive terminal placed in alignment with said axis (zz '), characterized in that between said movable support (4) and said clamp (7a, 7b) is a mechanical connection means capable of transmitting to said clamp a push towards the front parallel to said axis (zz ') and during the insertion of a connection piece (2) in a cell (2a) or on a conductive tab, said thrust is measured, it is compared to a threshold and, if this threshold is exceeded, the advancement of said carriage or of said articulated arm is automatically stopped and an alarm is triggered.  2. Method according to claim 1, characterized in that there is inserted between said movable support (4) and said clamp a second mechanical connection means capable of transmitting to said clamp a pull backwards parallel to said axis and, after having inserted a connection piece (2) in a cell (la) or on a conductive tab, we move said movable support (4) without loosening said clamp (7a, 7b), we measure the tensile force and we compare it to a threshold and if this threshold is reached, loosen said clamp and continue the return stroke of said mobile support (4) and, if this threshold is not reached, an alarm is triggered indicating a locking fault or a crimping fault of said connecting piece.  3. Method according to any one of claims 1 and 2, characterized in that said mechanical connection means are elastic connections placed between a tube (3) integral with said movable support (4) and a rod (9) carrying said clamp (7a, 7b), the relative displacement of said rod in said tube (3) is measured when said mobile support (4) is moved parallel to said axis - (zzl) and when said mobile support advances to engage a connection piece (2 ) in a cell or on a conductive tab, comparing said displacement relative to a first threshold and if this is exceeded, said mobile support is automatically stopped and an alarm is triggered and when said mobile support (4) moves back without the clamp either loosened, said displacement relative to a second threshold is compared and, if this second threshold is reached, the clamp is automatically loosened and said movable support (4) continues its return stroke and if at the end of said return stroke said second threshold has not been reached, an alarm is triggered.  4. Method according to claim 3, characterized in that said elastic connections consist of two springs placed between a shoulder (3a) of said tube (3) and two flanges (9a> 9b) carried by said rod (9) and we measure the relative movements of said rod (9) in said tube by means of two microswitches  (12, 13) placed on either side of the normal position of a bulge (9c) of said rod (9).  5. Device for automatically inserting pieces of  connection (2) crimped at the ends of a batch of conductive wires (5)  leaving an automatic wiring machine in cells (la)  insulating boxes (1) or on conductive terminals of the type  comprising a clamp (7a, 7b) which grasps each wire (5) immediately behind a connection piece (2) and a mobile support (4) making it possible to move said clamp relative to said shoemakers in three trirectangular directions, the l one (damn) is parallel to the axis of said clamp in order to bring each of said cells (la) or said conductive terminals into alignment with said clamp and to insert therein the connection piece located at the end of the wire held by said clamp, characterized in that each clamp has two jaws (7a, 7b) placed at the front end of a rod (9) which slides in a coaxial tube (3) which is integral with said support mobile (4) and said device comprises a first mechanical connection capable of transmitting a thrust forward between said tube (3) and said rod (9) and it further comprises means for comparing said thrust with a threshold and for stopping automatically moving forwards said mobi support (4) and to trigger an alarm when this threshold is exceeded.  6. Device according to claim 5, characterized in that it further comprises a second mechanical connection capable of transmitting rearward traction between said tube (3) and said rod (9) and means for comparing said force of traction at a threshold when said movable support (4) is moved back without loosening said clamp (7a, 7b), means for automatically loosening said clamp when this threshold is reached and means for triggering an alarm if this threshold is not reached during the return stroke of said mobile support.  7. Device according to any one of claims 5 and 6, characterized in that said mechanical connection is an elastic connection.  8. Device according to claim 7, characterized in that said tube comprises an internal shoulder (3a), said rod (9) comprises two flanges (9a, 9b) placed on either side of said shoulder and said device comprises two springs (10, 11) placed respectively between said shoulder and each of said flanges and means for comparing the relative displacements of said rod (9) inside said tube (3) with thresholds.  9. Device according to claim 8, characterized in that said rod (9) has a bulge (9c) and said tube (3) carries two microswitches (12, 13) placed on either side of the position of said bulge (9c) when the two springs are not compressed.