US3071844A

US3071844A - Method of making a terminal

Info

Publication number: US3071844A
Application number: US831853A
Authority: US
Inventors: Richard T Krause; Harold B Kalmar; Frank A Kukla
Original assignee: Malco Manufacturing Co Inc
Current assignee: Malco Manufacturing Co Inc
Priority date: 1959-08-05
Filing date: 1959-08-05
Publication date: 1963-01-08
Anticipated expiration: 1980-01-08

Description

1963 R. T. KRAUSE ETAL METHOD OF MAKING A TERMINAL Filed Aug. 5, 1959 INVENTORS 20 E/CIJA 12D 77 KEA use,

#mzou: aKALMAz AM BY F-EAA/K Kuzm haw, fleas Mic/(926W 4T7'OkA/E-Y5.

United States Patent Ofitice 3,071,844 Patented Jan. 8, 1963 3,071,844 METHOD OF MAKING A TERMINAL Richard T. Krause, Morton Grove, Harold B. Kalmar,

Des Plaines, and Frank A. Kukla, Riverside, [1]., as-

signors to Malco Manufacturing Company, Chicago,

Ill., a partnership Filed Aug. 5, 1959, Ser. No. 831,853 4 Claims. (Cl. 29155.55)

The present invention relates to a method of making electrical terminals and, in particular, relates to a method of making terminals of the round pin type. i

It is an object of the present invention to provide a new and improved method of making an electrical terminal.

It is another object of the present invention to provide a new and improved method for making a round pin type terminal from a rectangular pin type terminal.

It is a further object of the present invention to make a round pin type terminal having a perfectly continuous and uninterrupted pin surface.

It is yet a further object of the present invention to provide in a new and improved method the step of reworking the surface material of a round pin terminal to eliminate any surface roughness or unevenness.

It is yet another object of the present invention to provide a new and improved method for making a round pin terminal from a rectangular pin terminal including the step of effecting an axial plastic flow of the surface material of the round pin terminal, thereby producing a terminal having a smooth, continuous, and highly conductive surface.

The above and other objects are realized in accordance with the present invention by providing a new and improved method of making an electrical terminal. In the practice of the method, a rectangular pin type terminal is deformed in successive steps into a round pin type terminal having a highly conductive surface offering a lower electrical resistance to the transfer of electrical energy between the round pin terminal and a female terminal. In the initial step of the method, the rectangular pin is transformed into a generally rounded pin having flashing or the like extending outwardly. Thereafter, the flashing is removed to provide a substantially rounded pin having an uneven and rough surface resulting from the flashing removal step. To eliminate the surface rough ness, the material adjacent the surface of the round pin is reworked, to obtain a perfectly smooth and highly conductive surface.

The invention, both as to its organization and method of operation, taken with further objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanying drawing, in which:

FIG. 1 is a perspective view of a rectangular pin type terminal before it is deformed into a round pin type terminal in accordance with the method of the present invention.

'FIG. 2 is a perspective view of the terminal of FIG. 1 and deforming tools used in a first step of the method of the present invention;

FIG. 3 is a side elevational view of the terminal of FIG; 2 after the first step;

FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a perspective view of the terminal of FIG. 3 and shearing tools used in the second step of the method of the present invention;

FIG. 6 is an elevational view of the terminal of FIG. 5 after the second step;

FIG. 7 is an enlarged sectional view taken along line 7-7 of FIG. 6;

FIG. 8 is a perspective view of the terminal of FIG. 6 and the reworking tools used in the third step of the method of the present invention;

FIG. 9 is a perspective view of the terminal of FIG. 6 after the third step of the method of the present invention; and

FIG. 10 is an enlarged, perspective view taken along line 1010 of FIG. 9.

Referring now to the drawing, FIGS. 1 through 10 illustrate the various steps embodied in the method of the present invention. Briefly, the method is employed to transform rectangular pin type terminals into round pin type terminals and comprises three steps that can be practiced by automatic machinery. Consequently the round pin terminals can be quickly, easily, and inexpensively fabricated. It has been observed that round pin terminals made in accordance with the method of the present invention are perfectly rounded and exhibit better electrically conductive characteristics than round pin terminals made by existing or prior art methods.

Attention is directed to FIG. 1 wherein a rectangular pin terminal is illustrated in perspective and is identified generally by reference numeral 10. The rectangular pin terminals are readily stamped out of stock material, for example, brass or the like, by suitable automatic machinery. The rectangular pin terminal 10 is satisfactorily used in many installations and, in this connection, may be mounted with a bushing (not shown) to a support (not shown) in accordance with, for example, the method described and illustrated in the Alex Just et al. Patent No. 2,995,617, entitled Self Locking Terminal, and assigned to the same assignee as the present application.

As shown in FIG. 1, the terminalss upper portion comprises a wire-wrap shank 12 of generally rectangular cross section for accommodating an electrically conductive, bare wire. The extreme upper end of the wire-wrap shank 12 is beveled, as indicated at 14, to facilitate insertion of the shank 12 into suitable wire-wrap machinery which winds the bare wire tightly around the shank 12. Adjacent the lower end of the wire-wrap shank 12 is a gripping shank 16 which is adapted to coact with the above-referred to bushing (not shown) as described in the above-identified application. A pair of inwardly extending, locking notches 18 is located at the lower end of the shank 16 to accommodate the parts of the bushing (not shown) that are expanded during mountingof the terminal to the above-referred to support (not shown). As clearly seen, a pair of laterally extending flanges 20 are located intermediate the locking notches 18 and a rectangular pin 22.

The rectangular pin 22 depends downwardly or axially from the laterally extending flanges 20 and lies in the same plane as the wire-wrap shank 12, the gripping shank 16, and the flanges 20. The pin 22 is relatively short compared with the

shanks

12 and 16 and is rectangular in section throughout substantially its entire length, with the exception of a pair of opposite end corners which are beveled, as indicated at 24,'to facilitate the nesting of the pin 22 with a suitable female terminal (not shown).

In the practice of the method of the present invention,

the terminal 10 is moved to three stations wherein in three steps the rectangular pin 22 is transformed .to a round pin. At the first station, shown fragmentarily in FIG. 2, the'shank of the pin 22 is changed from its rectangular section to a generally circular section while the lower end of the pin 22 is changed from an angulated construction to a generally semi-spherical construction. The deformation of the pin '22 is effected by a die-forming punch 30 and a die-forming block 32, hereinafter referred to collectively as die-forming tools, which are movable relative to one another by suitable apparatus (not shown). The apparatus (not shown) generates an impact force adequate to cause the rectangular pin 22 to be deformed as described above.

More specifically, the terminal is moved to the first station and is suitably held in an upright position with its pin 22 depending downwardly between the die-forming

tools

30 and 32. Actually, the terminal 10 is located immediately adjacent to the stationary die-forming block 32 so that the desired deformation of the pin 22 occurs when the die-forming punch 30 moves toward and mates with the die-forming block 32. As shown, the die-forming punch 30 is of generally rectangular configuration and includes a coacting or mating face 34 in which is defined a generally semi-cylindrical recess 36. The recess 36 extends vertically in the face 34 and opens onto the upper surface 35, thereby defining a semi-circular cut-away portion 36a. The bottom 36b of the recess 36 is somewhat spherical to impart a semi-spherical end to the pin 22. The die-forming block 32 is of identical construction and likewise includes a coacting or mating face 38 in which is defined a semi-cylindrical recess 40. Identically to the recess 36, the recess 40 opens onto the upper surface 39 to form a semi-circular cutaway portion 40a and includes a somewhat spherical bottom 4012. It will be appreciated that the die-forming

tools

30 and 32 are so related to one another by the above-referred to apparatus that, 'when the faces 34 and 38 mate, the recesses 36 and 40 coact together to define a generally cylindrical recess having a semi-spherical bottom. In accordance with the first step of the method, the terminal 10 is properly positioned adjacent to the die-forming block 32, i.e., with the lower surfaces of the terminal flanges slightly spaced above the upper surface 38 and with the pin 22 partially located within the recess 40. In this position, only the pin 22 is located between the die-forming tools and 32. Thereafter, the above-referred to apparatus associated with the die-forming punch 36 is operated to cause the punch 30 to move toward the block 32. The punch 30 engages or strikes the pin 22 with such impact that the entire pin 22 is deformed.

As a result of the deforming blow of the punch 32, the "rectangular pin 22, as seen in FIGS. 1 and 2, is transformed into a substantially cylindrical pin, indicated by reference numeral 42, as seen in FIGS. 3 and 4. As

"shown in FIGS. 3 and 4, the pin 42 is not cylindrical or rounded in any sense since it includes surplus material or flashing 44 extending outwardly along the plane of the mating faces 34 and 38. The flashing 44 extends entirely around the pin 42, i.e., along opposite sides and along the bottom of the pin 42. Although it is desirable that all of the material of the rectangular pin 22 be transformed exactly into a cylindrical pin which has no flashing, such an objective cannot be achieved because of the variations in size and dimension of the rectangular pins 22 due to tolerances or the like and, further, because of the variations in the vertical positions of the pins 22 relative to the die-forming block 32. Accordingly, different amounts of flashing 44- are obtained on each of the pins 42 that are deformed as described above. In this connection, it should be appreciated that the recesses 36 and in the die-forming

tools

30 and 32 are not exactly semi-cylindrical but are somewhat less than semicylindrical. For example, instead of 180 degrees of recessed surface, only 178 degrees or 179 degrees of recessed surface is provided to compensate for the width of the flashing 44.

The terminal 10 shown in FIGS. 3 and 4 is then moved to the second station, shown fragmentarily in FIG. 5, whereat all of the flashing 44 is removed in a single t p. The removal of the flashing 44 is effected by a die-shearing punch 50 and a die-shearing block 52, hereinafter referred to collectively as die-shearing tools, which are relatively movable toward one another under the control of suitable apparatus (not shown). Particularly, the terminal 10 when at the second station is maintained in an upright position by suitable holding means (not shown) with its pin 42 depending downwardly between the die-shearing tools and 52. Actually, the terminal 10 is located immediately adjacent to the stationary dieshear-ing block 52 so that the flashing 44 is sheared off when the die-shearing punch 50 moves toward and mates with the die-shearing block 52. As shown, the dieshearing block 52 is of elongated construction, as contrasted to the generally rectangular construction of the die-forming

tools

30 and 32. The die-shearing block 52 includes a coacting or mating face 54 entirely comprising a recess 55. The recess 55 extends vertically and opens onto the upper surface 53 of the block 52 to define an arcuate cutaway portion 55a, in contrast to the above-referred to semi-circular cutaway portions 36a and 40a. This result obtains since the recess 55 includes approximately 130 degrees of recessed surface instead of the approximately 180 degrees recessed surface of the recesses 36 and 40. Similar to the recesses 36 and 40, the bottom 55b of the recess 55 is somewhat spherical to coact with the bottom portion of the pin 42.

On the other hand, the die-shearing punch 50 is of generally rectangular construction and includes a mating face 56 in which is defined a vertically extending recess 58. The recess 58 has a configuration best shown in FIG. 5 and is substantially deeper than the recesses 36 and 40. In any event the recess 58 specifically comprises a slot-like portion 60 having a curved bottom 66a and an adjacent generally semi-cylindrical rear portion 62 including a somewhat spherical bottom portion 62a. The portions 60 and 62 define a smooth and continuous recess surface and open onto the upper surface 63 to define an arch-like cutaway portion -58a. In this connection, the slot-like portion 60 also defines at the mating face 56 an arch-like shearing edge 64 for coacting with the flashing 44. The slot-like portion 60 is so constructed that the shearing edge 64 generally conforms to the cross section of the pin 42, exclusive of the flashing 44.

In the practice of the second step of the method, the terminal 10 is positioned adjacent to the die-shearing block 52 so that the right side 42a of the pin 42, as seen in FIG. 5, mates with the recess 54. In this position, the flashing 44 extends generally perpendicular to the elongated shearing block 52, and by virtue of the approximate degree surface of the recess 54, only those portions immediately adjacent to the flashing 44 are not supported by the die-shearing block '52. Thereafter, with the pin 42 of the terminal 10 being supported by the block 52 as described above, the apparatus (not shown) associated with the die-shearing punch 50 is operated to cause the die-shearing punch 50 to move toward the die-shearing block 52. During this movement, the shearing edg 64 engages the flashing 44 immediately adjacent the body of the pin 42, thereby shearing and removing the entire flashing 44 from the pin 42. Because of the relative dimensions of the die-shearing tools 50 and 52, the dieshearing punch 59 telescopes about the die-shearin g block 52. Specifically, after the flashing 44 is sheared from the pin 42, the shearing edge 64 moves by the pin 42, as well as the

opposite sides

66 and 68 of the block 52.

As a result of the shearing step, the pin 42 is changed into a substantially cylindrical pin 72 as illustrated in FIGS. 6 and 7. The pin 72 is not truly cylindrical, as best seen in FIG. 7, since the area adjacent the base of the flashing 44 is somewhat rough and uneven. Although the shearing edge 64 on the punch 50 is accurately dimensioned, unevenness is developed at the juncture between the pin 72 and the flashing 44. As shown, the rough and broken area, identified as '70, extends along the opposite sides and bottom of the pin '72 and provides a discontinuous surface which is undesirable and unsatisfactory since it produces a poor contact surface for transmitting electrical energy to a female or the like terminal.

To smooth out the surface of the pin 72, the terminal 10 is moved into the third station, shown fragmentarily in FIG. 8, whereat the rough and uneven area 7 on the pin 72 is removed. The terminal 10 is axially aligned with a burnishing tool 74 and, thereafter, the terminal 10 and the burnishing tool 74 are moved relative to one another. The engagement of the burnishing tool 74' and the terminal 10 causes the material adjacentthe surface of the pin 72 to be reworked so that the uneven strip 70 is smoothed out.

Specifically, the terminal 10, when at the third station, is grasped by suitable apparatus (not shown) which restrains the pin '72 against axial movement and aligns it with the burnishin-g tool 74. Suitable apparatus (not shown) associated with the burnishing tool 74 is operated to cause the tool to move axially toward the pin 72. As shown, the tool 74 is generally cylindrical in construction and includes a perfectly cylindrical, axially extending bore 76 that opens onto a face 77. As shown in FIG. 8, the mouth of the axial bore 76 is rounded, as indicated at 78 to facilitate entry of the pin 72 into the bore 76. The diameter of the bore 76 is slightly less than the diameter of the pin 72 so that as the tool 74 mates with the pin 72 a relatively great pressure is applied to the pin 72. As the tool 74 moves along the pin 72, the surface material is reworked to cause the roughness in the area 70 to be smoothed out. More particularly, a plastic flow of the surface material is obtained, with the result that the entire surface of the pin 72 conforms to the contour of the bore 76 which, as indicated above, is perfectly cylindrical.

Hence, after the third step, a perfectly smooth and uniform pin, identified by reference numeral 82, is obtained. As shown best in FIGS. 9 and 10, the body of the pin 82 is perfectly cylindrical, i.e., has a circular section, while the lower end of the pin is perfectly semispherical. Consequently, a terminal 10 having the abovedescribed round pin 82 can be mounted in a predetermined axial manner and, irrespective of its relative rotary position, the pin 82 satisfactorily mates with a female terminal. In addition, the perfectly cylindrical configuration of the body of the pin 82 provides a good contacting surface and, consequently, a good electrical connection is obtained between the terminal 10 and a female terminal (not shown).

Although the present method has been described in connection with the making of a round pin having a circular section, it will be appreciated that the method can also be practiced to produce a round pin having an oval or elliptical section. To this end, it is only necessary that appropriate forming tools, shearing tools and burnishing tools be substituted for the above-described forming

tools

30 and 32, shearing tools 50 and 52, and burnishing tool 74.

While the method described herein is at present considered to be preferred, it is understood that various modifications and improvements may be made therein, and it is intended to cover in the appended claims all such modifications and improvements as fall within the true spirit and scope of the invention.

What is desired to be claimed and secured by Letters Patent of the United States is:

1. A method of making a rectangular pin type terminal having a round pin terminal portion, said method comprising the steps of forming a pin terminal having a generally rectangular cross-section, deforming the lower end of the terminal into a generally round terminal portion having flashing extending outwardly, removing the flashing to produce a generally round terminal surface having discontinuities, and reworking the surface material of the round terminal portion to fill up and smooth out the discontinuities, thereby producing a terminal having a smooth and continuous surface.

2. A method of making a rectangular pin type terminal having a round pin terminal portion, said method comprising the steps of forming a pin terminal having a generally rectangular cross-section, deforming the lower end of the terminal into a generally round pin terminal portion having flashing extending outwardly, removing the flashing to produce a generally round terminal surface having discontinuities, and causing metal flow of the surface material of the terminal portion to smooth out the discontinuities by moving a tool axially along the terminal surface.

3. A method of making a pin terminal, said method comprising the steps of forming from a metallic blank a pin terminal having a generally rectangular cross-section, deforming the lower end of the terminal into a terminal portion having a generally curvilinear cross-section, said terminal portion having flashing extending outwardly, removing the flashing to produce a terminal portion having a generally curvilinear cross-section provided with discontinuities, and reworking the surface material of the terminal portion by moving a tool axially of the terminal portion to produce a terminal having a smooth and continuous surface.

4. A method of making a solid pin terminal, said method comprising the steps of forming from a solid blank material a solid pin terminal having generally rectangular cross-section, deforming the lower end of the terminal to produce a solid generally round terminal portion having flashing extending outwardly, removing the flashing to produce a generally round terminal surface having discontinuities, and reworking only the outer surface material of the terminal portion to smooth out the discontinuities, thereby producing a solid terminal portion havng a smooth and continuous surface.

References Cited in the file of this patent UNITED STATES PATENTS 774,242 Gates Nov. 8, 1904 1,391,365 Carlson Sept. 20, 1921 11,813,539 Hurley July 7, 1931 1,883,205 Whitehead Oct. 18, 1932 2,057,580 Layton Oct. 13, 1936 2,390,651 Iseman Dec. 11, 1945 2,614,465 Markert et al. Oct. 21, 1952 2,744,309 Graham May 8, 1956 2,939,100 Watts May 31, 1960