US3417599A - Compressing tool - Google Patents

Description

Dec. 24, 196% W. C. BURNS COMPRESSING TOOL Filed 001;. 26, 1966 i" 26 i 28 sa 3 Sheets-Sheet l 24, 1968 w. c. BURNS 3,417,599

COMPRESSING TOOL Filed Oct. 26, 1966 3 Sheets-Sheet 2 00 d: :I Q 0 j m {X in Filed Oct. 26, 1966 LORD,

POUND S W. C. BURNS COMPRESSING TOOL 3 Sheets-Sheet 5 INCH .060 .050 DEFLECTION United States Patent 3,417,599 COMPRESSING TOOL William Curtis Burns, Hershey, Pa., assignor to AMP Incorporated, Harrisburg, Pa. Continuation-impart of application Ser. No. 517,582, Dec. 30, 1965. This application Oct. 26, 1966, Ser. No. 589,613

6 Claims. (Cl. 72-410) This application is a continuation-in-part of my earlier application Ser. No. 517,582 filed Dec. 30, 1965.

This invention relates to the art of compressing tools and more particularly to a new and improved tool for swaging or crimping metallic terminal members to electrical conductors to form electrical and mechanical connections therebetween, and also for mechanically conneting any two articles adaptable to crimping techniques.

Electrical terminals of a given type normally are available in a variety of sizes to accommodate various size electrical conductors. Most crimping tools employ a separate set of dies for each size terminal. For a given set of dies and terminal size it can be determined to what extent the terminal barrel must be compressed around the conductor to achieve optimum electrical and mechanical characteristics. This optimum condition is then translated in terms of die closure or crimp height, that is the amount of distance between the upper and lower dies when bottoming occurs.

The use of crimp height has several distinct disadvantages. First a given size terminal usually is employed with more than one closely related wire size with the result that a set crimp height which is proper for one wire size will produce a crimp which is either too loose or too tight for another wire size. Secondly a given size terminal will vary slightly in size due to manufacturing tolerances with the result that a set crimp height will produce crimps of varying quality. Manufacturing tolerances may produce drastic size variations in the case of preinsulated terminals, that is where the barrel portion of the terminal comprises a layer of terminal material, a layer of metallic ferrule material and a layer of plastic insulating material. Thirdly the job of setting crimp height in a tedious one and this height must be reset for each set of dies.

It is therefore an object of the present invention to provide a tool which avoids the drawbacks of the type referred to above.

A further object is to provide a crimping tool whereby a single set of dies may be utilized for crimping a variety of sizes of terminal members.

A still further object of the present invention is to provide a tool which will produce uniform quality crimps on a given size terminal despite variations in size due to manufacturing tolerances.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purpose of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings, in which like reference numerals refer to like parts:

FIGURE 1 is a side elevational view of a tool embodying the teachings of the present invention;

FIGURE 2 is a sectional view taken along the line 22 of FIGURE 1 and showing the parts of the tool in engagement with a terminal but prior to applying force thereto;

FIGURE 3 is a cross-sectional view taken along the line 3-3 of FIGURE 2 but showing the tool in its closed position with respect to a relatively small terminal;

FIGURE 4 is a cross-sectional view similar to FIGURE 3 but showing the tool in its closed position with respect to a relatively large terminal;

FIGURES 5 through 8 are cross-sectional views of a pair of crimping dies used with the tool of FIGURE 1 showing the closed position of the dies when used on four different size terminals; and

FIGURE 9 is a graph showing the load-deflection characteristics of the tool of FIGURE 1.

Turning now to the drawings and in particular to FIG- URES l and 2 there is shown a tool 10 for use in connecting metallic terminals to electrical conductors. The tool 10 comprises a generally C-shaped head section 12 secured to a cylindrical body portion 14 by pins or the like as indicated at 16. A pair of male crimping dies 18 and 20 are rigidly secured at 22 to the head 12. For purposes of illustration the die 18 will secure the center conductor of a wire to a suitable terminal while the die 20 will secure the insulation of the wire conductor to the terminal. A pair of female dies 24 and 26 cooperate with the dies 18 and 20 respectively to produce the crimping operation. The dies 24 and 26 are mounted for independent reciprocating movement within the head 12 and are guided therein by a cover plate 28. A pin 30 extends from die 26 and is received within a circular opening 32 disposed in die 24 for retaining die 26 and for permitting relative motion between the dies 24 and 26.

A terminal locating arm 34 is mounted on the head 12 and is biased by a spring 36 to a position intersecting the opening between the male and female dies. The arm 34 insures that a terminal to be crimped is properly located between the male and female dies prior to operation of the tool.

An upper plate 38 is slidably disposed within body section 14 and has rigidly secured thereto the crimping die 24. The die 26 has a slotted section 40 which receives a force imposing means shown in the figures as a series of Belleville washers 42. These washers have substantially a truncated cone configuration and are normally formed of a spring steel. It is to be understood that although Belleville washers have been shown and constitute a preferred form of force imposing means, certain other spring members could be substituted for the washers without departing from the spirit of the present invention. The washers are retained within the slot 40 by means of a slidable plug 44 which has a press fit with the slotted section and extends beneath the lower end of the die 26. The plug 44 rests against the upper face of the plate 38. Compression of the washers 42 will cause relative motion between the dies 24 and 26 for a purpose to be later described. A return spring 46 is disposed between the upper portion of body section 14 and the plate 38 and biases the plate downwardly as seen in FIGURE 2 to normally bias the dies 24 and 26 out of contact with the dies 18 and 20.

Also disposed within the cylindrical body 14 is an intermediate plate 48 and a lower plate 50. A series of spring washers 52 are disposed between the upper plate 38 and the intermediate plate 48 and a further series of spring washers 54 are disposed between the intermediate plate 48 and the lower plate 50. The lower plate 50 rests on the upper end of a ram 56, the ram being slidable within the body 14 through an opening in the cylinder closure member 58. A screw or the like 60 extends through openings in the intermediate plate 48 and lower plate 50 and threadably engages the ram 56. The screw passes freely through the central openings in the wash- 6 ers 54 and 52 so as not to impede displacement thereof.

The closure member 58 has a pair of depending legs 62 extending therefrom to which are secured a pair of intermediate links 64. A pair of handles 66 are pinned at 68 to the links 64 and are pinned at 70 to the lower end of ram 56. In normal use the handles 66 will be grasped by an operator and pivoted between their opened and closed position to operate the tool and effect reciprocation of the ram 56.

In FIGURE 2 the tool is shown in its partially closed position, i.e. the crimping dies would be in light contact with a terminal. In this position the return spring 46 is partially compressed while the washers 42, 52 and 54 are in their relaxed condition. In the fully open position of the tool the lower plate 50 would be adjacent member 58 at the lower end of the cylinder 14. As the handles 66 are closed the ram 56 moves upwardly and positions the plates and washers as shown in FIGURE 2. In order to effect the crimp the terminal and wire conductor 72 are placed between the upper and lower crimping dies and the handles are pivoted toward each other to the position of FIGURE 2, whereat the terminal is loosely held after being positioned by the locating arm 34.

During movement of the plates 38, 48 and 50 from their lowermost position to their position shown in FIG- URE 2 there will be no resistance met by the crimping dies and thus the ram 56, so the plates and washers will move upwardly as a unit with no compression of either the washers 42, 52 or 54. The lower insulation crimping die 26 is positioned slightly in advance of the lower terminal barrel crimping die 24 so that the initial contact will be made between the terminal and the dies and 26. Any further closure of handles 66 will result in resistance being exerted by the terminal 72 and this resistance will be countered by the force exerted by the washers 42, 52 and 54.

Before describing the movements of the various parts of the tool during a Crimping operation it is first necessary to discuss the characteristics of typical Belleville washers and also to discuss the particular washers which make up the three ditferent washer series employed in the tool. Reference will be made to FIGURE 9 wherein there is shown a graph illustrating the spring characteristics of the particular spring washers employed in the present tool. It is to be understood that the particular washers which will be described constitute a preferred form of the invention and that other washers or sprin members could be used as long as these other washers or spring members exhibit characteristics which are similar to the characteristics of the preferred form of washers.

Conical spring washers may be produced to provide varying load-deflection characteristics. The shape of the load-deflection curve for a particular spring washer will depend on the relationship between the thickness of the washer and the amount of oflset or dish. The load deflection curve shown in FIGURE 9 is a composite curve which represents the force output exerted by the washers 52 and 54. The particular washers chosen for the series 54 will exert the force of 1500 pounds when deflected to their flat position. From FIGURE 9 it can be seen that a deflection ranging between .070 and .080 inch will yield approximately 1500 pounds. If the washers 52 were not present in the tool the load-deflection curve would follow the dotted line 74 since the washers 54 would have reached their flat position at this point and would yield an infinite load with no further deflection. The particular washers chosen for the group 52 will exert a force of approximately 3000 pounds when fully deflected. As seen in FIGURE 9 a displacement ranging between .142 and .152 inch will yield approximately 3000 pounds. If the washers 54 were not present in the tool the load deflection curve of the washers 52 would substantially follow the path indicated by the dotted line 76.

It is an extremely desirable characteristic of the conical spring washers that the curve is substantially flat in the area of maximum load output. Because of this there would be a substantially constant amount of force exerted on various terminals even though the individual terminals vary slightly from each other in size.

The particular tool illustrated has been designed for use with four difl'erent size terminals. The largest size, shown in phantom in FIGURE 5, requires a force of 3000 pounds for an effective crimp. The intermediate and small size terminals, shown in FIGURES 6-8 respectively, require a crimping force of approximately 1500 pounds for an efiective crimp, The relative position of the upper and lower dies is shown in FIGURES 58 and it is important to note in these figures that the dies never bottom or completely close regardless of the size terminal being used, this being a drastic departure from conventional crimping tools. Since the dies do not bottom, the manufacturing tolerances of the dies which must be rigidly held in conventional tools are not critical with the present tool, thus resulting in a considerable savings in the cost of die manufacture.

When it is, desired to crimp either the intermediate or small size terminals shown in FIGURES 6-8 there will be appreciable movement of the tool handles 66 prior to contact being made between the crimping dies and the terminal. Further closure of the handles will result in force being applied through the terminal to the dies and this force will be opposed by the lower series of washers 54. The upper series 52 will not be immediately affected since these are higher load washers and will remain rigid during low load while the washers 54 will begin to compress.

In FIGURE 3 the tool is shown in its position after having fully crimped a relatively small terminal. It can be seen that the washers 54 are approximately flat so that they are delivering their full 1500 pounds whereas the washers 52 remain substantially in an unstressed condition. Since the terminal is relatively small and considerable hand travel has taken place prior to the washers being loaded, the total deflection of the washers will be in the range of .070 to .080 inch resulting in the 1500 pounds pressure being applied to the terminal.

The operation thus far described indicates that 1500 pounds is being delivered to the lower terminal crimping die 24 and thus to the terminal barrel. However it is desirable to concentrate the 1500 pound load on the die 24 but not on the die 26 since a lower load is adequate for the insulation portion of the terminal and therefore means are provided for decreasing the load delivered by the lower insulation crimping die 26. This means constitutes the washers 42 previously described. The washers 42 are designed in this particular embodiment of the tool to deliver 300 pounds upon full compression. On the intermediate or smaller size terminals where 1500 pounds is applied to the barrel it is desirable to place a load of approximately pounds on the insulation portion of the terminal. Movement of plate 38 upwardly during the crimping operation will cause the slidable plug 44 to exert a force on the washers 42 and thus an the die 26. However the washers 42 will compress under the load thus allowing the die 26 to move relative to the die 24 to thereby impart the lower load to the terminal insulation.

When a relatively large terminal is placed in the tool for crimping there will be relatively little handle movement prior to contact between the crimping dies and the terminal. Therefore the handles 66 will move an appreciable distance under load thus imparting appreciable deflection to the washers 54 and 52. In FIGURE 4 the tool is shown in position after completing a crimp on a relatively large terminal. Due to the large displacement, in the area of .142 to .152 inch, the washers 54 will be totally compressed and the washers 52 will also be compressed into a near flat condition. Thus referring again to FIG- URE 9 the total load delivered by the two series of washers will be approximately 3000 pounds. Also, due to the large displacement under load of the ram 56 and thus the upper plate 38, the washers 42 in the terminal insulating die 26 will be compressed to a near fiat condition and will deliver their full 300 pounds which is the desirable load applied to the insulation of a large terminal.

The various groups of washers 42, 52 and 54 have been shown in specific configurations such as a parallel arrangement and a series arrangement. It is to be understood that the particular groups of washers may be changed in order to produce the desired load output.

It can be seen that the objects of the invention have been achieved in that a tool has been provided which will operate on various size terminals and will produce a constant high quality crimp regardless of slight variations in size of the terminals within a given group. Also a single set of dies may be employed for use with the various size terminals.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is ofiered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

What is claimed is:

1. A compressing device comprising a tool body, a first die fixed to said body, a second die movable relative to said body and cooperable with said first die to compress :an article disposed therebetween, first means secured to said second die and movable relative to said body, second means movable relative to said body and said first means, operating means to effect movement of said second means, and first and second resilient means interposed between said first and second means, the first said resilient means having different force transmitting capabilities than the second said resilient means, whereby said operating means causes said resilient means to transmit force from said dies to an article disposed between said dies, the amount of said force being dependent upon the degree ofcompression of said first and second resilient means.

2. A compressing device as set forth in claim 1 wherein said first and second resilient means comprise spring washers.

3. A compressing device as set forth in claim 1 further comprising a third die mounted on said first means, and resilient means interposed between said third die and said first means for permitting limited relative motion between said third die and said second die.

4. A compressing device as set forth in claim 1 wherein plate means are disposed between said first and second resilient means.

5. A compressing device :as set forth in claim 1 wherein said first resilient means has approximately twice the force transmitting capability of said second resilient means.

6. A compressing device as set forth in claim 1 wherein said first and second dies remain unclosed during a compressing operation.

References Cited UNITED STATES PATENTS 2,953,185 9/1960 Lazar 72-412 3,281,926 11/1966 Frastaci 72-41 FOREIGN PATENTS 218,593 12/1961 Austria. 735,670 6/1966 Canada.

CHARLES W. LANHAM, Primary Examiner.

G. P. CROSBY, Assistant Examiner.

US. Cl. X.R.

Claims (1)

1. A COMPRESSING DEVICE COMPRISING A TOOL BODY, A FIRST DIE FIXED TO SAID BODY, A SECOND DIE MOVABLE RELATIVE TO SAID BODY AND COOPERABLE WITH SAID FIRST DIE TO COMPRESS AN ARTICLE DISPOSED THEREBETWEEN, FIRST MEANS SECURED TO SAID SECOND DIE AND MOVABLE RELATIVE TO SAID BODY, SECOND MEANS MOVABLE RELATIVE TO SAID BODY AND SAID FIRST MEANS, OPERATING MEANS TO EFFECT MOVEMENT OF SAID SECOND MEANS, AND FIRST AND SECOND RESILIENT MEANS INTERPOSED BETWEEN SAID FIRST AND SECOND MEANS, THE FIRST SAID RESILIENT MEANS HAVING DIFFERENT FORCE TRANSMITTING CAPABILITIES THAN THE SECOND SAID RESILIENT MEANS, WHEREBY SAID OPERATING MEANS CAUSES SAID RESILIENT MEANS TO TRANSMIT FORCE FROM SAID DIES TO AN ARTICLE DISPOSED BETWEEN SAID DIES, THE AMOUNT OF SAID FORCE BEING DEPENDENT UPON THE DEGREE OF COMPRESSION OF SAID FIRST AND SECOND RESILIENT MEANS.

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