Apparatus And Method For Aligning A Plurality Of Connector Mounted Pins By Deformation And Reformation Thereof

Abstract

An alignment apparatus and method for aligning a plurality of connector mounted pins is shown having a work table for mounting a connector thereon which is capable of linear displacements in four directions along X and Y axes. A fixture engages the ends of the connector mounted pins for retaining these pins in the desired aligned position while the connector is displaced with respect to that position. The mounting frame is displaced in one direction along the X-axis beyond the elastic limit of the pins for permanently deforming them and then displaced in a second direction beyond the elastic limit for again deforming the pins. The mounting frame is finally displaced in the first direction passed the center position a distance sufficient to remove the deformation caused by the last displacement and then returned to the center position for aligning the pins with respect to the center position along the X-axis. These same steps are repeated along the Y-axis for aligning the plurality of pins with the desired center position along that axis, thus aligning the pins with the center position located at the intersection of the X and Y axes.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus and method for aligning a plurality of connector mounted pins; and, more particularly, to an alignment apparatus that automatically engages a plurality of unaligned connector mounted pins and displaces these pins through a pattern for removing previously formed deformations by uniformly deforming the pins to align them with true center positions.

Recently, the Gardner-Denver Company of Grand Rapids, Michigan introduced a punch-card controlled machine that would automatically strip insulation from a solid wire, properly route it on a wiring panel, and then wrap it around the desired terminal post of an electrical connector. Thus, a solderless wrap interconnection is effected quickly and inexpensively. The Gardner-Denver automatic wire-wrapping machine has the capability of terminating over 500 wires an hour thereby reducing wire terminating costs by more than 400 percent over the older manual methods of wire-wrapping. In the wire-wrapping process, the bare end of an insulated wire is wrapped around a terminal pin having sharp corners. Since the wrapping is done under tension the wire and the terminal pin are deformed at the point of contact, i.e., the corners. Hence the wrapped wire is held to the pin by the elastic stresses left in the wire and the pin. The average pressure between the wire and the pin is 30,000 psi; this pressure is more than sufficient to meet the requirements of a gas-tight connection.

The advent of the automatic wire-wrapping machine increased the structural requirements for the electrical connectors to be used in conjunction therewith. One important requirement is that the electrical connector pins must be positioned or centered within tolerance circles having radii of 0.010 inch about the true center positions. Another important requirement is that the electrical pins of the electrical connector have sufficient strength to withstand deformation during the wire-wrapping operation.

One electrical connector developed for use with the automatic wire-wrapping machine comprises a plastic base with square pins located within square openings therein. These pins are retained within the base by twisting the pins whereby a twisted portion of the pin extends into the square opening within the plastic base. This connector is more completely described in a pending patent application Ser. No. 760,561 by Frank G. Spadoni, Jr. which was filed on Sept. 18, 1968, entitled Electrical Connector with Twisted Posts, and is assigned to the same assignee as the present invention. This application recognizes the problem of positioning the plurality of connector mounted pins within a series of symmetrical tolerance circles each having a maximum radius of 0.010 inch.

The connector described in the pending patent application mentioned above still requires some straightening of the pins in order to meet the stringent requirements of the punch-card controlled, automatic wire-wrapping machine. Many approaches have been developed and utilized in an attempt to properly align each pin within the required tolerance circle. One practiced method visually projects the tips of the pins onto a calibrated screen having circles inscribed thereon to represent the tolerance circles. An operator then views the screen and adjusts each pin with a special tool to insure that the pins are positioned within the required tolerance circles. This procedure is obviously time consuming and expensive.

A second approach, utilized by prior art devices, places a pin tip gripping fixture over the connector pins and displaces these pins through a rotary movement which is increased and then decreased to return the pins to a center or starting position. This arrangement has been used in an attempt to provide an apparatus which automatically aligns the connector pins within the required tolerance circles. However, this arrangement has been found to be unsatisfactory as the rotary motion tends to crack and chip the plastic base at the point where the pins enter that base. This cracking and chipping adversely affects the resistance of each pin to withstand the push out force exerted by the automatic wire-wrapping machine during the wire-wrapping thereof. Further, the rotational motion of the gripping fixture burnishes the plating at the end of each pin where the fixture is engaged therewith. This adversely affects the electrical characteristics of the pin. Finally, the rotary displacement has never satisfactorily straightened the individual pins with the result that many connectors are rejected and must be manually straightened.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a method for aligning a plurality of connector mounted pins to within a given tolerance of a plurality of true center positions through the controlled deformation and reformation of the pins.

It is another object of the present invention to provide apparatus for automatically aligning a plurality of connector mounted pins with respect to true center positions on the connector.

Still another object of this invention is to provide an alignment apparatus which aligns a plurality of connector mounted pins without cracking, chipping or otherwise damaging the base portion of the connector.

A further object of this invention is to provide alignment apparatus which is capable of engaging the ends of a plurality of connector mounted pins and aligning the pins within a given tolerance without burnishing the plating thereon.

Yet a further object of the invention herein presented is to provide alignment apparatus for a plurality of connector mounted pins which is capable of economically aligning the pins in a minimum amount of time.

In accomplishing these and other objects, there has been provided mounting means for receiving a connector and pin holding means for engaging a plurality of connector mounted pins. Displacement means are provided for displacing the mounting means and pin holding means with respect to each other in a predetermined pattern along first and second linear axes.

BRIEF DESCRIPTION OF DRAWINGS

Other objects and many of the attendant advantages of the present invention will become readily apparent to those skilled in the art as a better understanding thereof is obtained by reference to the following description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a perspective view, showing an apparatus for aligning a plurality of connector mounted pins which incorporates the present invention;

FIG. 2 is a side elevational view, showing a second embodiment of the apparatus for aligning a plurality of connector mounted pins;

FIGS. 3 and 4 are enlarged detailed drawings, partially in section, showing a single connector pin before and after engagement with the pin holding means; and

FIG. 5 is an enlarged detailed view, illustrating the profile of the cam shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, FIG. 1 shows a true alignment apparatus 10 including a work table 12 which mounts a pin-type connector 14 having a connector base 15 and a plurality of pins 16 symmetrically arranged and parallelly extending from the base of the connector. The work table 12 includes a base plate 18 having a slot 20 across the upper surface thereof for forming a way which slideably retains an intermediate plate 22 therein. The intermediate plate is provided with a second transverse slot 24 across the upper surface thereof at right angles to the slot 20. A connector mounting plate 26 is slideably retained within the way formed by the slot 24.

The upper surface of the connector mounting plate 26 is arranged to receive various sized pin-type connectors 14. Each connector is generally constructed with a plastic base having alignment apertures 28 in opposite ends thereof. Alignment posts 30 are mounted in the connector mounting plate 26, as by a press fit, to receive the apertures 28 within the connector. After a pin-type connector 14 is placed upon the connector mounting plate 26, it is clamped thereto by a clamping assembly 32 which engages the sides of the base 15 for retaining the connector 14 upon the mounting plate 26. The clamp assembly may be secured in a fixed position by a quarter turn locking bolt 34.

A pin engaging fixture 36 having apertures 38 symmetrically arranged within the pin contacting surface thereof is mounted within a suitable chuck 40 for lowering the fixture 36 over the connector mounted pins 16. The apertures 38 are provided with chamfered openings 42 for engaging the ends of the pins 16 and guiding them into the apertures 38. The details of the aperture 38 and chamfer 42 are more clearly seen in FIGS. 3 and 4.

The intermediate plate 22 and the connector mounting plate 26 are slideably adjusted on the ways formed by the slots 20 and 24 by turning a pair of lead screw handles 44 and 46, respectively. These lead screw handles drive lead screws 48 which engage and displace the intermediate plate 22 and the connector mounting plate 26 in a conventional manner.

Each lead screw handle and lead screw may be turned by a suitable torque motor 50 which engages and drives the lead screws 48 through a pulley and a belt drive arrangement, 52 and 54. Thus, it will be seen that the intermediate plate 22 and the mounting plate 26 are displaced along the X-axis, indicated by the arrow 56, through the manual adjustment of the lead screw handle and lead screw, 44 and 48, or by electrically driving the torque motor 50 attached to the lead screw. In a similar manner, the connector mounting plate 26 is displaced along the Y-axis, indicated by arrow 58, by manually adjusting the lead screw handle 46 or by driving the motor 50 attached to the lead screw 48. The displacement of the intermediate plate 22 and, in turn, the connector mounting plate 26 along the X-axis and the displacement of the connector mounting plate 26 along the Y-axis may be controlled by a suitable electronic controller, as illustrated at 60. The electronic controller may be one of several well known devices, such as a tape controlled programmer.

A second embodiment of the present invention is illustrated in the FIG. 2 wherein the connector base 15 of the connector 14 is mounted within a mounting fixture 64 which is suitably arranged for raising and lowering the connector pins 16 into a pin engaging fixture 66. The pin engaging fixture 66 is affixed to the upper surface of a fixture mounting plate 68 which slideably mounts a way 70 formed within an intermediate plate 72. The intermediate plate 72 is similarly mounted in a way 74 formed within a base plate 76. In this arrangement, the fixture mounting plate 68 and the intermediate plate 72 are displaced along the X-axis by the rotational motion of a cam 78 which engages a cam follower 80 attached to the fixture mounting plate 68. The cam 78 urges the mounting plate 68 against a spring 82 which is mounted within a spring holder 84. A suitable rack and pinion arrangement, 86 and 88, supplies the rotational motion to the cam 78 through the attachment of the pinion 88 to the cam. The rack 86 may be linearly driven by various means, such as a pneumatic cylinder 90. The fixture mounting plate 68 may be displaced along the Y-axis by a similar cam driving arrangement, not shown.

In operation, the connector 14 is placed on the connector mounting plate 26 (FIG. 1) and clamped thereto by tightening the bolt 34 for locking the clamp angle 32 against the connector base 15. The pin engaging fixture 36 is then lowered for engaging the ends of the pins 16. In the preferred embodiment, it has been found that the pins need only extend 0.060 inch into the aperture 38 beyond the chamfer 42. As mentioned hereinabove and as illustrated in FIGS. 3 and 4, the purpose of the chamfer 42 is to guide the pins 16 into the aperture 38. During assembly of the connector 14, the pins 16 are either manually or machine inserted into the base 15 and then twisted or otherwise permanently affixed therein. Prior to the development of the automatic wire-wrapping machine, the connector was then ready for incorporation into a system by manually attaching individual wires to each pin. However, as mentioned hereinabove, the automatic wire-wrapping machine requires that the pins 16 be aligned within tolerance circles having a radius not greater than 0.010 inch. Due to this, the connectors must be examined and the pins must be straightened to insure that they fall within the tolerance circles.

At this stage of assembly, the pins 16 each retain a memory caused by the deformation of the pin as it was manually or machine inserted into the connector base 15 and twisted or otherwise connected therein. This deformation memory cause the pins 16 to be displaced in various random directions. As the pin engaging fixture 36 is lowered, the chamfer 42 engages the ends of the pins and guides them into the apertures 38. However, this does not displace the pins enough to cause a deformation that could overcome the memory formed therein by the assembly of the pins 16 and the base 15.

In order to overcome the deformation memory, the connector mounting plate 26 is first displaced from its center or starting position to the right, for example, along the X-axis 56 a distance sufficient to exceed the elastic limit of most of the pins 16 for permanently deforming these pins in that direction. The connector mounting plate 26 is then returned to its center position and displaced in the opposite direction along the X-axis 56 for deforming all of the pins in the opposite direction. The connector mounting plate is next returned to the center position and displaced for a second time in the first direction along the X-axis far enough to cancel the deformation in the last mentioned direction. Then the connector mounting plate is returned to the center position. This operation thus deforms most of the pins in a first direction and then deforms all of the pins in a second direction along the X-axis. It will be understood that some pins could be initially displaced to the right, in this example. Thus, the first displacement might not deform these pins sufficiently to remove the deformation memory they retain. However, the double deformation insures that all the pins have been deformed at least once in a direction which opposes the direction of the original deformation memory. Thus, when the connector mounting plate 26 of FIG. 1 (or the pin engagement fixture 36 of FIG. 2) is returned to zero and displaced for the second time in the first direction a distance sufficient to remove the last deformation placed therein, each pin is uniformly deformed and thereby aligned with the center position along the X-axis.

It will be obvious that each pin 16 could still retain a deformation memory in a direction other than along the X-axis. This would cause that pin to be aligned with the center position along the X-axis while being displaced from the center position along the Y-axis. Thus, the procedure described hereinabove is repeated along the Y-axis. That is, the pins are displaced upwardly, for example, in a first direction along the Y-axis 58. The connector mounting plate 26 is returned to the center position and displaced in an opposite direction along the Y-axis before being returned to the center position. The pins are finally displaced for a second time in the first direction along the Y-axis for a distance sufficient to remove the deformation caused by the last displacement prior to being returned to the center position. After the second operation, the pins are aligned with the center position formed at the intersection of the X and Y axes for insuring that all pins are aligned with the true center positions of the connector.

In the preferred displacement pattern, the first and second displacements from the center position along either axes are each of sufficient magnitude to exceed the elastic limit of the pins. This displacement is generally not a critical one. However, the last displacement in the first direction is more critical and varies depending on the pin material, the number of pins, and pin dimensions. In order to compensate for this, the last displacement must be easily adjusted. This may be accomplished by providing the cam 78, FIG. 5, with a high point 92, a low point 94 and a zero or starting point 96 on each side thereof. This provides for the first and second displacements of the fixture mounting plate 68. On the side of the high point 92 away from the low point 94 the cam slopes toward a second low point 98, while the cam slopes toward a high point 100 on the side of the low point 94 opposite the high point 92.

Thus, as the pneumatic cylinder 90 urges the rack 86 upwardly, FIG. 2, a stop 102 is removed from a cammed notch 104 to free the rack. Once free, the pinion 88 turns cam 78 for urging the high point 92 thereof against the cam follower 80 and displacing the mounting plate 68 to the left. The mounting plate 68 is then displaced to the right as the cam low point 94 passes the cam follower 80. When the zero point 96 is reached, the stop 102 drops into a second cammed notch 106 and slides out again as the rack continues to be urged upwardly. An adjustable stop 108 stops the rack movement and, in turn, stops the mounting plate 60 at the desired second displacement in the first direction. Obviously, the adjustment of the stop 108 adjusts the point on the cam between the zero point 96 and the high point 100 for adjusting the amount of the last displacement.

The cylinder is then programmed to urge the rack in a downwardly direction until the cammed notch 106 again engages the stop 102. The cammed notch and stop retain the rack motion until the next X-axis cycle is started by removing the stop 102 from the notch 106. It will be noted that the next X-axis cycle will be reversed. That is, the displacement will be to the right and then to the left. The operation is identical, however, with a second stop 110 adjusting the travel of the last displacement.

In the preferred embodiment, the pin material is gold plated phosphor bronze. Each pin 16 is arranged with a square cross section having a dimension of 0.025 inch per side and a length of 0.638 inch from the surface of the connector base 15 to the end thereof. The pin engaging fixture 36 is lowered to a point which allows the end of each pin 16 to extend 0.060 inch into the aperture 38 beyond the chamfer 42. The connector mounting plate 26 is then displaced to the right along the X-axis for 0.120 inch and returned to the center position or zero. It is then displaced to the left for 0.120 inch and returned to zero, and finally displaced to the right for a distance of 0.060 inch before being returned to zero. These steps are repeated along the Y-axis by displacing the connector mounting plate 26 up 0.120 inch and returning it to zero, displacing it down 0.120 inch and returning it to zero, and then displacing it up 0.060 inch prior to returning it again to zero. As indicated hereinabove, the last displacement of 0.060 inch along the X and Y axes may be adjusted by adjusting suitable devices, such as stops 108 and 110.

In practice, the displacement steps may be incorporated by manually cranking the lead screw handles associated with the work tables of various machines, such as a milling machine. This process has also been practiced by programming a tape controlled machine for displacing the work table thereof through displacements having the magnitude and direction indicated hereinabove. This arrangement has worked satisfactory and has been found to substantially reduce the production costs of each connector while providing pin alignment within tolerance circles having radii not greater than 0.010 inch from the true center positions.

FIG. 2 illustrates a second embodiment wherein the work table 12 may be cam driven by various actuator means, such as a pneumatic cylinder 90 whose piston is connected to a rack 86 and pinion 88 which in turn connects to a cam 78 and cam follower 80. Obviously, the pneumatic cylinder 90 may be replaced by the electric motors 50 of FIG. 1, by a hydraulic system, or by any other commonly known mechanical, electro-mechanical, or electrical arrangement.

It will be obvious to those skilled in the art that the present invention may be practiced by displacing the connector mounting plate or by displacing the pin engaging fixture. Further, it will be obvious that the amount of displacement and the number of displacements may vary from connector to connector depending on the number of pins, their material, and the arrangement thereof. The important feature of the present invention is that a sequence of linear displacements along a given axis removes deformation memory and insures that each pin is aligned with each other pin at the true center positions thereof. By following this procedure along a pair of axes, it is possible to determine the point at which the two axes cross and thus align the pins with this point for positioning them within the tolerance circles centered on the true center positions. Obviously, it is the recognition of this principle that forms the heart of the present invention while the machinery which embodies this invention may be varied depending on the production rate, equipment available, and dimensions of the connectors to be aligned. Accordingly, the present invention should be limited only by the appended claims.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for aligning a plurality of unaligned connector mounted pins with respect to each other and to a true center position by deformation and reformation thereof comprising the steps of:

placing the ends of said pins within a fixture located on the center position and holding said pins in conformity with the desired true center position;

moving said fixture with respect to said connector off said center position in a first linear direction along a first axis for flexing said pins beyond the elastic limit of most of said pins thereby permanently deforming most of said pins in said first linear direction;

moving said fixture with respect to said connector in a second linear direction along said first axis, opposite said first direction, and beyond said center position for flexing said pins beyond the elastic limit of all of said pins thereby permanently deforming all of said pins in said second direction;

moving said fixture with respect to said connector in said first linear direction beyond said center position for flexing said pins and removing said permanent deformation, caused by said movement in said second direction, to align said pins along said first axis with respect to said center position as said fixture is moved with respect to said connector back to said center position;

moving said fixture with respect to said connector off said center position in a third linear direction along a second axis for flexing said pins beyond the elastic limit of most of said pins thereby permanently deforming most of said pins in said third linear direction;

moving said fixture with respect to said connector in a fourth linear direction along said second axis, opposite said third direction, and beyond said center position for flexing said pins beyond the elastic limit of all of said pins thereby permanently deforming all of said pins in said fourth direction; and

moving said fixture with respect to said connector in said third linear direction beyond said center position for flexing said pins and removing said permanent deformation, caused by said movement in said fourth direction, to align said pins along said second axis with respect to said center position as said fixture is moved with respect to said connector back to said center position, thus aligning said pins with said true center position located at the intersection of said first and second axes.

2. Apparatus for aligning a plurality of unaligned connector mounted pins with respect to each other and to a true center position by deformation and reformation thereof, comprising:

frame means for mounting said connector;

fixture means having aligned apertures therein for receiving the ends of said pins to be aligned on said center position;

first displacement means for linearly displacing said fixture means with respect to said frame means in a first direction from said center position along a first axis, in a second opposite direction beyond said center position along said first axis, in said first direction beyond said center position, and back thereto;

second displacement means for linearly displacing said fixture means with respect to said frame means in a third direction from said center position along a second axis, in a fourth opposite direction beyond said center position along said second axis, in said third direction beyond said center position, and back thereto;

said displacement means causing said displacements in said first, second, third and fourth directions to exceed the elastic limit of said pins for permanently deforming said pins in said directions; and

said displacement means further causing said last displacements in said first and third directions to overcome said permanent deformations in said second and fourth directions for permanently deforming said pins in alignment with said center positions along said first and second axes and thereby aligning said pins with said true center position at the intersection of said axes.

3. Alignment apparatus for aligning a plurality of connector mounted pins with respect to a true center position by deformation and reformation thereof, comprising:

mounting means for mounting said connector;

pin holding means for receiving said plurality of pins and initially displacing said pins into the center position desired;

said mounting means and said pin holding means including means for allowing displacement therebetween along first and second axes;

first displacement means for linearly displacing said mounting means and said pin holding means in a first and then a second opposite direction along said first axis beyond the elastic limit of said plurality of pins thus deforming said pins respectively in said first and second directions, said first displacing means further displacing said pins in said first direction passed said center position and back thereto for removing said last deformation in said second direction and aligning said pins with said center position along said first axis; and

second displacement means for linearly displacing said mounting means and said pin holding means in a third and then a fourth opposite direction along said second axis beyond the elastic limit of said plurality of pins thus deforming said pins respectively in said third and fourth directions, said second displacement means further displacing said pins in said third direction passed said center position and back thereto for removing said last deformation in said fourth direction and aligning said pins with said center position along said second axis;

whereby said pins are permanently aligned with said center position along said first and second axes and are thereby aligned with said true center position at the intersection of said axes.

4. Alignment apparatus as claimed in claim 3, wherein:

said first and second axes are X and Y axes;

said first displacement means first displaces said pins in a positive first direction and back to zero, secondly displaces said pins in a negative second direction and back to zero, and thirdly displaces said pins in said positive first direction and back to zero along said X-axis; and

said second displacement means first displaces said pins in a positive third direction and back to zero, secondly displaces said pins in a negative fourth direction and back to zero, and thirdly displaces said pins in said positive third direction and back to zero along said Y-axis.

5. Alignment apparatus as claimed in claim 3, wherein:

said first and second displacement means are adjustable for adjusting the length of said third displacements along said axes; and

said first and second displacements along said axes are substantially twice said third displacements along said axes.

6. Alignment apparatus as claimed in claim 3, wherein:

said pin holding means is capable of movement along X and Y axes; and

said mounting means is fixed with respect to said X and Y axes while being moveable along a Z-axis to engage said pins.

7. Alignment apparatus as claimed in claim 3, wherein:

said first and second displacement means include driven cam means.

8. Alignment apparatus as claimed in claim 3, wherein:

said mounting means includes work table means capable of movement along X and Y axes; and

said pin holding means is fixed with respect to said X and Y axes while being moveable along a Z-axis to engage said pins.

9. Alignment apparatus as claimed in claim 3, wherein:

said first and second displacement means include driven screw thread means for imparting motion along said axes.

10. Alignment apparatus as claimed in claim 9, additionally comprising:

electrical motor means for driving said screw thread means; and

adjustable control means for controlling said electrical moor means and thereby controlling the displacement of said work table means along said axes.