WO1992001531A1

WO1992001531A1 - Methods and devices for inserting automatically a male part into a female part

Info

Publication number: WO1992001531A1
Application number: PCT/FR1990/000555
Authority: WO
Inventors: Claude Ricard
Original assignee: Claude Ricard
Priority date: 1989-01-27
Filing date: 1990-07-20
Publication date: 1992-02-06
Also published as: FR2644379A1; FR2644379B1

Abstract

The invention relates to methods and devices for inserting automatically a male part into a female part wherein it penetrates with slight play. A device according to the invention is comprised of a multi-axis automatic machine controlled by a mini-computer (6) and including a table (5) displaceable along three tri-rectangular axes (Ox, Oy, Oz), which table carries a servomotor (7) which drives a vertical shaft (8) carrying a cover (9) which supports an insertion device (12) driven about a horizontal axis (10) by means of a servomotor (11). The insertion device carries an insertion clamp (15) whose jaws (16) grip a connecting male part (2) in order to insert it automatically in a female cavity (1). An application is on automatic wiring machines.

Description

Methods and devices for automatically inserting a male part into a female part.

DESCRIPTION

The subject of the invention is methods and devices for automatically inserting a male part into a female part into which it penetrates with little play. The technical sector of the invention is that of the construction of automatic machines, in particular robots wiring.

In the remainder of the description, reference will be made to an application of the methods according to the invention in the construction of wiring robots which are automatic machines controlled by a central mini-computer which unwind the lengths of programmed electrical conductor wires, which strip the ends of the sections of wires, which equip them with connection pieces or male or female terminals and which automatically insert these connection pieces for example in cells of insulating housings or on electrical connector terminals or on the terminals of electrical appliances mounted on a plate.

It should be noted that this example is not limiting and that the methods and devices according to the invention can be applied in all cases where male parts have to be mechanically inserted into female parts into which they penetrate with a very weak game

The mechanical insertion of the male connection pieces into female connection pieces poses problems because of the small clearance between these pieces which requires that the two pieces be perfectly aligned before being brought together and then inserted one into the other.

In practice, alignment is rarely perfect. The axes of the female part and of the male part can be parallel but offset from each other. The axes of the two parts may also have a parallelism defect. The two faults can be combined.

The value and the direction of the axis offset as well as the value and the direction of the angular difference between the axes vary randomly and are therefore not known individually but they obey a law of statistical distribution.

Given the small clearance between the two parts to be inserted into each other, it frequently happens that a misalignment causes a relative displacement of the distal end of the male part with respect to the opening of the female part greater than the clearance and in this case when the male part is brought closer to the female part, the front or distal face of the male part abuts frontally against the edges of the opening of the female part and cannot penetrate into those -this. In this case, either the automatic insertion device stops automatically, which stops the operation of the wiring machine, or it continues to push, which results in deformation of the part to be inserted and can lead to deterioration of the device. insertion. The objective of the present invention is to provide means which allow a male part to be automatically inserted into a female part into which it penetrates with very little play without the front end of the male part running the risk of coming up against the front against the edges of the opening of the female part even if the two parts are not perfectly aligned.

The object of the invention is achieved by a process for mechanically inserting a male part into a female part, according to which at least one of the two parts is mounted on a multi-axis machine making it possible to move the two parts one by relative to the other in translation along three trirectangular axes, one of which is parallel to the axis of the female part and constitutes the insertion axis and rotates around at least one axis perpendicular to said insertion axis and the following sequence of operations is automatically performed: - one of the parts is rotated relative to the other by a determined angle (α) around a first axis of rotation (Ox or Oz) perpendicular to the insertion axis (Oy);

- the two parts are brought closer to each other by a translation parallel to said insertion axis (Oy) so that the distal end of the male part penetrates at an angle and partly into the opening of the female part ; - The two parts are moved relative to each other by a translation parallel to the second axis of rotation so that one of the lateral sides of the male part comes into contact with an edge of the opening of the part female. - the two parts are made to pivot with respect to each other by an angle opposite to the previous pivoting angle about an axis parallel to said first axis of rotation passing through said edge of the opening of the part female and the two parts are moved relative to each other in translation parallel to said insertion axis (Oy) so that said male part which is already partially engaged in said female part fits into it without abut against the edges of the opening of said female part.

Advantageously, the two parts are pivoted relative to each other about an axis which is perpendicular to the plane parallel to the insertion axis in which the clearance between the two parts is the smallest.

In the case where the male part has a small clearance with respect to the female part along two perpendicular planes passing through the insertion axis, the two parts are pivoted relative to each other around two axes perpendicular to the said plans.

A device according to the invention comprises a support which can be moved automatically along three trirectangular axes (Ox, Oy, Oz) by three servomotors controlled by a mini-computer, a fourth servo-motor controlled by said mini-computer which rotates a first shaft parallel to one of said axes (Oz), a fifth servo motor which is supported by a yoke fixed to said first shaft and which rotates a second shaft parallel to another of said axes (Ox) which second shaft carries an insertion device which holds an insertion clamp provided with two jaws which grip said male part which jaws are parallel to the third of said axes (Oy) which constitutes the insertion axis or between the insertion clamp and the insertion device.

Advantageously, the insertion device comprises a jack whose rod is parallel to the insertion axis and carries at its end the insertion clamp and an elastically deformable link is interposed between the rod of the jack and the insertion clamp . The invention results in the possibility of mechanically inserting male parts into female parts into which they penetrate with very little play, preventing the front face of a male part from abutting head against the edges of the opening of a female part despite the misalignments between the two parts.

The pivoting and the lateral displacement of the two parts with respect to each other are calculated according to the theoretical geometrical dimensions of the parts, the manufacturing tolerances and the known statistical values of the current misalignments.

The alignment faults or the size faults of the two parts are random faults which follow statistical laws and it is possible to statistically determine a maximum value of these faults whose probability of being exceeded is very low. When the two parts are pivoted relative to each other about an axis perpendicular to the insertion axis, the distal face of the male part which was substantially perpendicular to the insertion axis pivots and one of its ends approaches the opening of the female part and at the same time approaches the insertion axis. We choose a pivot angle such that the approximation of the axis is greater than the maximum value of the defects so that when we bring the two parts closer to each other after having rotated them, we are certain that the edge of the male part which has been offset towards the female part during the rotation, penetrates into the female part without meeting the edges of the latter so that the distal end of the male part engages at an angle and partially in the female part.

After which the male part is moved laterally relative to the female part in a direction perpendicular to both the insertion axis and the axis of rotation so that one of the lateral edges of the male part comes place in contact with one of the edges of the opening of the female part and all the play available between the two parts is on the side opposite the point of contact then the male part is again pivoted relative to the female part by an angle opposite to the previous angle of rotation around the line or point of contact of the male part with the female part which is near the end of the male part so that at the end of the reverse pivoting the distal end of the male part is engaged inside the female part and the male part becomes again parallel to the female part and one can finish inserting it without it does not abut against the edges of the opening of the female part.

The following description refers to the appended drawings which represent, without any limiting character, an exemplary embodiment of a method and a device according to the invention.

Figure 1 is a schematic representation of steps la and the of a method according to the invention.

Figure 2 is an elevational view of a device according to the invention.

Figure 3 is a view along III III of the device beyond Figure 2. Figure 1 shows the successive steps la to lf of a method according to the invention.

Mark 1 represents a female part and mark 2 a male part which must be inserted mechanically and with very little play in the female part 1. For example, part 2 is a connection part or a male terminal crimped to the end of an electric wire coming out of an automatic wiring machine and the part 1 is a cell of an insulating box or a female connector into which the male terminal must be inserted mechanically. Conversely, the female part 1 can be a female terminal crimped at the end of an electrical conductor which must be mechanically engaged on a male plug of an electrical connector.

Although more particularly described are examples relating to the insertion of two electrical connection parts one into the other, these examples are not limiting and the methods and devices according to the invention can be applied in all cases where a male part must be mechanically assembled with a female part into which it penetrates with very little play.

The mechanical insertion of a male part into a female part poses delicate problems of relative positioning of the two parts with respect to each other when the clearance between the parts is very small, which is frequently the case. Figure la represents a case where the axis yiy'i of the female part is parallel to the axis y2Y'2 of 1 ^& male part but slightly offset from it with a length a greater than the lateral clearance between the two parts in a plane parallel to the plane passing through the two axes yiy'i and y2y ^* 2- Figure lb represents a case where the axes yiy'i and 2y ^* 2 of the two parts are not parallel and form between them a small angle ε.

A third case of possible misalignment combines both a lateral offset according to FIG. 1a and a parallelism defect according to FIG. 1b.

In all these cases, when one mechanically moves one of the parts relative to the other parallel to the axis yι_ '1 of the female part which we will call the insertion axis, the distal end 2a of the male part risks abutting against the edges of the opening of the female part and in this case the insertion cannot take place and there is a risk of deforming or damaging one of the parts or the insertion tool.

The figure represents the first step of a method according to the invention. There is shown in this figure three trirectangular axes forming a trihedron oriented in the direct direction, the axis Ox is perpendicular to the plane of the figure and directed towards the observer, the axis Oy said axis of insertion is parallel to the axis of the female part and the Oz axis is perpendicular to the other two. To simplify the presentation we will assume that Figures 1a to 1f represent elevation views, that is to say that the axis Oz is vertical. An observer placed on the Oz axis and looking towards the Ox axis has the Oy axis to his left.

The figure represents a first step of the process during which one of the parts is pivoted relative to the other, for example the male part 2 relative to the female part around one of the two axes Ox or Oz, for example around the Ox axis perpendicular to the plane of the figure. This rotation takes place around an axis Ox, the relative position of which is known with respect to the part 2, and an angle of rotation a is chosen which has a determined value and direction. The figure shows it for example an angle of rotation around the axis Ox in a clockwise direction. During this rotation one of the edges A of the front face 2a of the male part parallel to the axis of rotation Ox approaches the opening of the female part, that is to say advances along the axis Oy and also approaches the Oy axis of the female part. If the rotation took place anticlockwise, it would be the opposite edge A 'which would approach the insertion axis at the same time as it would approach the opening. The figure represents a case where the clearance between the male part and the female part is very small in the vertical plane defined by the axes Oy and Oz and in this case the male part is pivoted around an axis Ox perpendicular to the plane Oy, Oz.

If the clearance between the two parts is small only in the horizontal plane Ox, Oy the male part is pivoted about the axis Oz.

If the play between the two parts is small both in the horizontal plane and in the vertical plane, one of the parts is pivoted relative to the other successively or simultaneously around the two axes Ox and Oz.

In all cases, the male part is therefore made to pivot relative to the female part by an angle α determined in absolute value and in the direction of rotation around at least one axis which is perpendicular to the axis Oy of insertion. Figure Id shows a next step in the process. During this, the two parts are moved in a relative translational movement parallel to the insertion axis Oy so that the distal end 2a of the male part approaches the opening of the female part . During this step the edge A which is closest to the opening penetrates into it and the distal end 2a of the male part engages at an angle in the opening of the female part.

Whatever the initial misalignment between the male and female parts, edge A penetrates into the female part without abutting on the edges of the opening.

Indeed, during the rotation step shown in the figure, the edge A approached the axis of the female part of a length proportional to the angle α and this angle is chosen large enough for this length to be greater than the maximum misalignment such as the defect a in FIG.

The figure represents the next step of the method according to the invention.

During this step, the parts 1 and 2 are moved in a relative translational movement such that the male part 2 moves parallel to the axis Oz until a point on the lateral edge of the male part located on the same side as the edge A comes into contact with a front edge B of the opening of the female part which is parallel to the axis Ox around which the male part was made to pivot during step le.

Figure lf shows in solid lines the next step of a method according to the invention. During this step, the two parts are pivoted relative to each other about an axis Bx parallel to the axis ox passing through the edge B of the opening of the female part which is in contact with the male part, the pivot angle -α being inverse to the previous pivot angle so that at the end of rotation the axes y ^ y 'i and y2Y * 2 of the male and female parts have become parallel again and l he distal end of the male part is fully engaged in the female part.

FIG. 1f represents in dotted lines the final step of a method according to the invention during which the two parts are displaced relative to each other in translation parallel to the axis Oy so that one inserts the male part of the desired length into the socket of the female part without the distal end of the male part which is already engaged in the female part not likely to abut against the edges of the opening thereof. For the sake of clarity, Figures 1d to 1f show separate steps.

In practice, the translational movements parallel to the axis Oy and the rotational movement around the axis Bx can be successive or simultaneous. We will see in the following description of a device for the implementation of the invention that one of the parts, for example the male part is connected to the gripping device which allows the move in translation or in rotation by an elastic link so that during phase le when one of the edges of the male part came into contact with an edge B of the opening of the female part, if continues to move the male part, the elastic connection is deformed. Likewise during the reverse rotation, the elastic connection causes the male part to pivot around its line of contact Bx with the female part.

Figures 2 and 3 respectively show an elevational view and a top view along III III of a device for the implementation of the invention.

These figures show a male part 2, for example a terminal crimped at the end of an electrical conductor 3 and an insulating housing. which delimits cells 1 which constitute as many female parts in each of which a male part 2 must be mechanically inserted.

According to a nonlimiting example, the insulating housings can be mounted on a plate which is mounted on a table which can be moved by servo motors controlled by a mini-computer along three trirectangular axes, one of which coincides with the axis Oy of alveoli 1.

The movements being relative one can replace the displacements of the female part along three axes by displacements of the male part. This is the case which is illustrated in FIGS. 1 and 2.

The reference 5 represents a set of three carriages or a manipulator arm or a horizontal table or a support which is displaceable in translation along three trirectangular axes Ox, Oy, Oz.

The axis Oy is parallel to the axis of insertion, that is to say to the axis of the female cells 1.

The Oz axis is vertical. The table is moved in translation by three servo motors which are connected to a mini-computer 6 which delivers the set values to be followed to the servo motors.

Table 5 carries a fourth servo-motor 7 Q i rotated by a vertical shaft 8 which carries a vertical yoke whose two arms support a horizontal shaft 10 whose axis XX 'is perpendicular to the insertion axis YY' . The shaft 10 is rotated by a fifth servo motor 11. The shaft 11 carries an insertion device 12 which is placed between the two arms of the yoke 9 and which can therefore pivot around a vertical axis ZZ 'and around a horizontal axis XX' both perpendicular to the insertion axis YY '.

The insertion device comprises an insertion cylinder 13 whose piston 13a is connected by a rod 13b to a clamp support 14. The axis YY ′ of the rod 13b is the insertion axis which is parallel to the 'one of the axes Oy according to which the table 5 can be moved. The clamp support 1 _ carries a clamp 15 which is provided with two elongated nozzles 16, parallel to the axis YY ', which hold the male part. There are shown in Figures 2 and 3 springs 17 interposed between the clamp support 14 and the clamp body 15 to indicate that the connection between these two parts is elastically deformable.

For example, the clamp body 1 can be inserted into an elastomer block which can deform elastically. As a variant, in the case where the male part is crimped at one end of a relatively flexible conducting wire 3, the two beaks 16 of the clamp can grip the wire a little behind the terminal so that the wire itself constitutes a deformable link between the clamp and the terminal. As a variant, an elastic connection can be inserted between the clamp 1 and the insertion device 12.

The mini-computer 6 is programmed as a function of the dimensions of the male part 2 and of the cells 1 to send sequentially set values to the three servo motors which control the movements in translation of the table 5 to the two servo motors 7 and 11 and to cylinder 13. The cycle of operations is as follows. The insertion device 12 grasps a gripper body 15 which is moved - for example by a conveyor and whose spouts 16 hold a male terminal 2. The mini-computer automatically controls translational movements of the table 5 along the three axes Ox, Oy, Oz polish bring the male clamp 2 in alignment with a socket 1 into which it must be inserted.

At the end of this stage the distal end of the male part 2 is placed near the opening of a ^" cell 1. There may be a slight misalignment between the two parts. -

The computer 6 then controls the servomotor 7 to rotate the male part by a determined angle α around the vertical axis ZZ 'of the motor if the clearance between male and female part is minimum in the horizontal plane.

If the play between male and female part is minimum in the vertical plane, the computer 6 controls the servo-motor 11 to rotate the male part by an angle a around the horizontal axis XX 'of the motor 11.

If the play between male and female part is weak both in the vertical plane and in the horizontal plane the computer 6 can control the motor 11 has made turn the male part around the axis XX 'either along the axis ox in the case where the motor 7 and the motor 11 for pivoting the male part 2 both by an angle α around the vertical axis ZZ 'and by an angle β around the horizontal axis XX'.

The computer then controls a slight movement of the table 5 along the axis Oy to cause a corner of the front face of the male part to penetrate into the female part then it controls a slight lateral movement of the table 5 either according to the 'Oz axis in the case where the motor 7 has rotated the male part around the ZZ axis' is along the two axes Oz and Ox in the case where the two servo motors 7 and 11 have rotated the male part. These lateral displacements bring one of the lateral sides of the male part into contact with an edge of the opening of the cell 1. If the displacements of the table along the axes Ox and Oz are slightly greater than what would be strictly necessary for the male part to come into contact with the female part, the elastic connection 17 deforms and absorbs the difference. In practice, the displacements of the table are programmed according to Ox and Oy so that they are always greater than what would be strictly necessary to take account of the tolerances in the dimensions and possible misalignments.

The computer 6 then controls the servomotor 7 or the servomotor 11 or both to rotate them by an angle opposite to the angle from which they previously rotated. During this rotation the male part 2 is pressed against an edge of the opening of the cell 1 and the deformations of the elastic connection 17 cause the male part to pivot around its line or its point of contact with the edge opening of the female part. The computer then controls the jack 13 which inserts the male part into the cell 1 of a determined length.

Claims

1. Method for automatically inserting a male part (2) into a female part (1) characterized in that at least one of the two parts is mounted on a multi-axis machine making it possible to move the two parts one relative to the other in translation along three trirectangular axes (Ox, Oy, Oz) one of which (Oy) is parallel to the axis of the female part and constitutes the axis of insertion and in rotation around at least one axis (Ox or Oz) perpendicular to said insertion axis (Oy) and the following sequence of operations is automatically carried out:

- One of the parts is made to rotate relative to the other by a determined angle (α) around at least a first axis of rotation (Ox or Oz) perpendicular to the insertion axis (Oy); - the two parts are brought closer to each other by a translation parallel to said insertion axis (Oy) so that the distal end of the male part penetrates at an angle and partly into the opening of the female part ;

- the two parts are moved relative to each other by a translation parallel to the second axis of rotation so that one of the lateral sides of the male part comes into contact with an edge (B) of the opening of the female part (1).

- the two parts are made to rotate relative to one another by an angle (-α) opposite to the previous pivoting angle about an axis parallel to said first axis of rotation passing through said edge (B) of the opening of the female part and the two parts are displaced relative to each other in translation parallel to said insertion axis (Oy) so that said male part which is already partially engaged in said female part s 'inserts into it without abutting against the edges of the opening of said female part.

2. Method according to claim 1 for inserting a male part into a female part into which it enters with a very small clearance characterized in that the two parts are pivoted relative to each other by an angle determined (α) around an axis (Ox or Oz) which is perpendicular to the plane parallel to the insertion axis (Oy) in which the clearance between the two parts is the smallest.

3. Method according to claim 1 for inserting a male part in a female part into which it enters with a very f____e clearance in two perpendicular planes passing through the axis of insert_ < ^• _! _ characterized in that one rotates the two parts one relative to the another around two orthogonal axes (Ox and Oz) perpendicular to said planes.

_. Device for automatically inserting, in a female part (1), a male connection part (2) crimped at the heart end. flexible conductive wire (3), which device comprises an insertion clamp (15), provided with spouts (16), which enclose said conductive wire behind said zeal connection piece (2) and an insertion device ( 12) which holds said insertion clamp (15) characterized in that it comprises a support (5) automatically movable along three trirectangular axes (Ox, Oy, Oz) by three servomotors controlled by a mini-computer, a fourth servomotor (7), which is controlled by said mini-computer (6) and which rotates a first shaft (8) parallel to one of said axes (Oz) and a fifth servomotor (11) which is supported by a yoke ( 9) fixed to said first shaft (8) and which rotates a second shaft (10) parallel to another of said axes (Ox), which second shaft (10) carries said insertion device (12) which holds said clamp and which includes means (13) for moving it parallel to the third axis e (Oy) which constitutes the insertion axis.

5. Device according to claim 4 characterized in that said insertion device comprises a jack (13) whose rod (13b) is parallel to said insertion axis (yy ') and carries at its end said insertion clamp (15).

6. Device according to claim 5 characterized in that an elastically deformable connection is interposed between said cylinder rod (13b) and said insertion clamp (15).

7. Device according to claim _ characterized in that a resiliently deformable link is interposed between said clamp and said insertion device.