US2696747A - Toggle-actuated crimping tool with full-stroke compelling mechanism - Google Patents

Description

Dec. 14, 1954 M, D. BERGAN ,6 6

TOGGLE-ACTUATED CRIMPING TOOL WITH FULL STRQKE COMPELLING MECHANI,

Filed 061. 2, 1951 2 Sheets-Sheet 1- IN VEN TOR.

Array/1E? Dec, 14, 1954 M D BERGAN 2,696,147

TOGGLE-ACTUA'TED. CRIMPING TOOL WITH FULL-STROKE COMPELLING MECHANISM Filed Oct. 2, 1951 '2 Sheets-Shoat 2 v INVENTOR.

I Airmen/5r United States Patent ()fiice 2,696,747 Patented Dec. 14, 1954 TOGGLE-ACTUATED CRIMPING TOOL WITH FULL-STROKE COMPELLING MECHANISM Martin D. Bergan, Westfield, N. J., assignor to The Thomas & Betts Co., Elizabeth, N. J., a corporation of New Jersey Application October 2, 1951, Serial No. 249,309

6 Claims. (Cl. 81-15) The invention relates to a crimping tool of the pliers type particularly but not exclusively designed for use in deforming a small malleable sleeve into a crimping engagement with wires within the sleeve for making a durable joint therebetween in forming electric fittings.

Such crimps are usually formed by the use of properly designed dies forming the jaw elements of a squeeze clamp of the leverage type but even then such crimps are difficult to form properly by manual power and dependence upon leverage alone renders the tool so long as to be unwieldy. It has been suggested in this art to utilize a toggle form of power multiplying mechanism between an operating handle and a shiftable jaw for obtaining the largest possible mechanical advantage from the manual force available to the operator, and the present disclosure is a development of this form of crimping tool.

A factor controlling the forming of such crimps is that the sleeve must not be crushed and this is very apt to happen in the toggle lever types of crimping tools where the dies are free to come into contact as the toggle nears its position of delivering its maximum output of work, for instance, just as the toggle reaches its dead center position. As herein used, the reference to the toggle being on dead center means that position of the toggle at which it is capable of delivering its maximum possible force on the associated shiftable jaw clamp and at the same time is free of jamming or locking of the toggle. In the preferred form of the invention herein disclosed the toggle is stopped in its advance at a point close to but just before the toggle linkage approaches a straight line. In the case illustrated a tool nine and one-half inches long is capable of exerting a squeeze pressure over a ten, or at the rate of several tons per square inch by a manually imposed squeeze action on the handles of the tool.

The primary object of the invention is to provide a crimping tool of easily manageable weight and size and by means of which the manual power available is transformed economically into the maximum possible force which the tool can deliver to the sleeve and which, when at its maximum, operates on the sleeve to attain the restrained and limited degree of deformation intended by the designer of the fitting and in this way avoid during the final instant of the squeeze any possibility of crushing the sleeve.

Broadly, this objective is obtained by utilizing in a pliers type tool a toggle system for applying force to the movable jaw of the squeeze clamp and in regulating the approach of this jaw so that when the toggle is delivering its maximum power output, that is, when the toggle is just about to reach its dead center position, the shiftable jaw at that instant is in what is called the point of nearest approach to the fixed jaw and in which the shiftable jaw when it is stopped in its advance just short of the straightening out of the toggle is actually spaced from the fixed jaw that distance which the designer of the fitting has previously determined to be the proper final thickness of the resulting fitting and thus short of any squeeze conditions which may be regarded as a crushing action on the fitting.

Another circumstance which complicates the problem solved by the present disclosure is that the sleeves to be crirnped are of a very small diameter often sufiiciently small to take Nos. 18-22 wires. With such small sleeves care must be exercised in designing and in manufacturing the crimping tool herein featured, to reduce to a minimum the running fit of the pivot pins in the several apertures in the chain of parts which makes up the toggle, and thus eliminate as far as possible all loose clearances in the operation of the tool.

Recalling that it is required in crimping operations that there should be a nicety and pre-intended exactness in the extent to which the sleeve should be deformed, it is a common fault in this art that in actual practice the required bonding of sleeve and conductors is not had due to the fact that the deformation was not progressed as far as was necessary to obtain the intended degree of squeeze on the sleeve. While the indentation of the side of the sleeve in effecting the crimp must not proceed so far as to crush or even deform the metal abnormally, it must proceed to an extent to give the requisite bond between the sleeve and the conductors therein and the leeway therebetween is not very extensive and is practically non-existent in the case of small wires. With presently known forms of crimping tools the operator does not know just where to stop the squeezing action and is quite apt to stop the approach of the jaws to each otl'ifrdbefore the intended degree of squeeze on the sleeve is a It is the intent here to provide what may be called a custom-made form of crimping tool in which the operating space between the jaws in their final operating position is preset accurately by the manufacturers of the tool and the disclosure features a non-adjustable type of toggle as part of the jaw-advancing mechanism so as to defeat possibility of the operator changing at will the setting of the tool to provide some other space setting of the jaws for which the tool is not designed by its manufacturer.

In order to compel the operator after he has started the shiftable jaw on its working stroke to complete the same and thus insure, time after time, the formation of the identical dimensions of crimp for which the tool was custom designed, the present disclosure features a non-return type of interlock which permits a free movement of the shiftable jaw under constantly multiplied power when moving toward the fixed jaw but which resists any retreating movement of the shiftable jaw until the Working stroke has been fully completed, after which the shiftable jaw may be returned idly to its initial fully open position without any resistance from the interlock.

Broadly, this aspect of the invention is provided by means of an interlocking mechanism between the operating handle of the toggle and the main body carry-.

ing the fixed jaw to defeat reverse movement of the shiftable jaw while it is in an intermediate position in its approach to the fixed jaw and which interlock is in an inoperative position when the shiftable jaw is in either of its two extreme limiting positions to thus permit a reversal of the shiftable jaw after it has completed its crimping stroke.

Various other objects and advantages of the invention will be in part obvious from an inspecttion of the accompanying drawings and in part will be more fully set forth in the following particular description of one form of crimping tool embodying the invention, and the invention also consists in certain new and novel features of construction and combination of parts hereinafter set forth and claimed.

In the accompanying drawing,

Fig. l is a view in side elevation of a crimping tool forming a preferred embodiment of the invention and shown in its normal fully closed position and with the handles broken off to save space and with the handles as well as the jaws in their positions of nearest approach;

Fig. 2 is a plan view looking down upon the showing in Fig. 1 when turned upside down to disclose the under side of the tool as shown in Fig. 1;

Fig. 3 is a view in left end elevation of the tool shown in Figs. 1 and 2;

Figs. 4 to 6, inclusive, are each vertical sectional views taken in the longitudinal medial plane of Fig. 2 and along the line 44, showing successive positions of the squeeze jaws, the toggle-forming parts, the interlock and the sleeve operated upon as the rockable jaw moves from a fully open position (not shown) into its initial contact with the sleeve as shown in Fig. 4; through the intermediate o if) non-retreatable and crimping position of the jaws as shown in Fig. and into its final crimping position of nearest approach of the rockable jaw to the fixed jaw as shown in Fig. 6.

In the drawing there is shown a crimping tool of the pliers type used in the illustrated case to crimp a metal sleeve S onto wire conductors C contained in the sleeve.

The tool includes a long main body, frame or relatively stationary member 11 and a long lever 12 pivotally connected at pivot pin 13 and with the member and lever provided respectively with extensions forming a lower handle 14 (Figs. 4-6) and an upper handle 15 normally disposed in parallel relation as shown in Fig. l. Member 11 and lever 12 are made of tool steel castings and are of relatively great depth in their flatwise dimension in order to absorb strains from the several pivots. An upturned solid end 16 of member 11 forms a seat for receiving a replaceable die element 17 forming the relatively fixed jaw of a squeeze clamp. A rockable link 18 pivoted to the member 11 forms a coacting die and the relatively shiftable jaw of the clamp. The shiftable jaw 18 is connected to lever 12 by a pair of short connecting links 19.

The portion of the frame member 11 between the end 16 and its handle 14 is of greater depth than the handle and forms a rugged head to the tool. The frame 11 is slotted at its head end as shown in Fig. 2 and provides a pair of spaced-apart parallel cheek plates 21) and 21 integrally connected at their ends and between which plates the rockable jaw 18 and toggle-forming parts are for the most part contained and protected.

The upturned end 16 is provided on its inner side with an upstanding, flat face 22 against which abuts the die element 17 which is provided at its upper end with a hook 23 overlapping a ledge 24 upstanding from the end 16. An alternate structure provides a screw for replaceably securing an apertured end of the die element 17 to the end 16 as shown in the copending application of Maurus Logan, Serial No. 257,090, filed November 19, 1951.

At its lower end the die element 17 is reduced in width and formed into a disk-like boss 25 (see Fig. 3) provided with an anchoring pin hole 26 through which passes a dowel pin 27 whose ends are fitted in the cheek plates 20 and 21 with a driven fit and thus to anchor the die element to the main body 11. Link 18 forming the shiftable jaw is of a triangular form with its lower end reduced in width and formed into a disk-like boss 28 rockably mounted on the pin 27 besides the boss 25.

The fixed jaw 17 is provided on its work-engaging side facing the shiftable jaw 18 with a plurality of depressions or nests 29 and for this reason jaw 17 is sometimes referred to as a nest block. The shiftable jaw 18 is provided on its work-engaging side facing the nest block with a plurality of projections or indentors 30, one for each nest and for this reason jaw 13 is sometimes referred to as the indentor block. Where the distance forming the work arm, as measured between the fulcrum at 37 and the point at C (Fig. 4) where work is done on the sleeve, is less than the power arm as measured between the fulcrum and the point at 33 where the toggle force is applied, the rockable link 18 forms a lever of the second class, thus adding its mechanical advantage to that produced by the toggle. The nest block and the indentor block are each made of hard die steel.

The lever 12 is a lever of the first class and is fulcrumed intermediate its ends to provide a long arm which forms the upper handle 15 and a very short arm 31 which projects from the pin 13 towards the shiftable jaw and forms the power element of the toggle connection. The links 19 are in pairs on opposite sides of the arm 31, as shown in Fig. 2, and at one end are pivoted thereto by dowel pin 32 which forms the knee of an equal length arm toggle. The opposite or forward ends of the links 19 are on opposite sides of the upper, wide end of the shiftable jaw 13 and are pivoted thereto by a pivot pin 33. The axes of pins 13, 32 and 33 are substantially in a dead center alignment as shown in Fig. 6, when the jaws 1718 are in a desired pre-fixed spaced-apart relation controlled by the length of the replaceable pair of short connecting links 19. It is a feature of this disclosure that each of the parallel links 19 is factory produced to have identically the same length measured between the centers of their pivoting pins.

The shiftable jaw 18 has two limiting positions, one a fully open position at the beginning of its operative stroke 4 and a position of nearest approach to, but spaced slightly from, the fixed jaw and spaced an exact predetermined factory preset distance from the fixed jaw as shown in its fully closed position in Fig. 6.

It is a feature of this disclosure that the die-forming elements 17 and 18 may be readily replaced by die elements of a different shape or size simply by removing the two pins 27 and 33, replacing the die elements with others and replacing the pins, all of which can be done without necessity of disturbing any of the other parts. While the present disclosure features the use of factory determined lengths to the pair of short connecting links 19 best suited for the particular size of sleeve currently being crimped and free of any possibility of the operator making any adjustments thereof, it is suggested that any particular size of tool may be sold with replaceable links of slightly different sizes and adapted selectively to replace the links currently in use, say, when a different point of nearest approach to the fixed jaw is desired.

in order to defeat any possibility of the operator terminating the actuating stroke before the desired form of crimp has been made, the present disclosure features a one-way interlock between the jaws of the clamp to permit a freedom of approach of the jaws under squeeze pressure to each other while resisting retreat of the jaws after they have started on their squeezing act and until the crimping stroke is completed. For this purpose there is provided a one-way form of interlock between the main body 11 and the toggle mechanism actuating the shiftable jaw. For this purpose lever 12 is provided with a broad, flat, rugged, plate-like extension 34, depending from the pin 13 and extending at an angle of about 45 degrees rearwardly toward the free end of the handle 14. The short arm 31 and the extension 34 form, in effect, a bell crank lever rocking about the pin 13 and from which lever projects the long actuating arm or handle 1215. Differently described, the lever 12 may be considered as a three-arm lever with the pin 13 at the inner ends of all three arms 31, 34, and the part of lever 12 which leads to the handle 15. This has the effect of localizing strains largely on the main pin 13 from which they are transferred directly to the two rugged cheek plates 20, 21. The lower end of the extension is formed with a short line of angular teeth forming therewith a ratch or ratchet 35 and rearwardly of the same the lower edge of the extension is provided with an arched recess forming a rear clearance 36. The advanced side of the extension is cut back to form a stop wall 37 and therebeyond in the clear to form a forward clearance 38. A pawl 39' pivoted between the cheek plates coacts with the ratch 35 to form an interlock between the lever 12 and the body 11. The interlock is of the ratchet and pawl type and in the form shown the ratch constitutes a section of a ratchet wheel.

The pawl 39 is of the bell crank lever type; is located beneath the extension and is pivotally mounted in a pawl roll pin 40 extending between and whose ends are secured to the cheek plates. Pawl spacers 41 center the pawl between cheek plates. One arm of the pawl forms a rounded nose 42 which projects towards the pin 13 and across which the ratch 35 moves back and forth. The nose has a length measured from the axis of pin 40 which causes its free end to extend into the rear clearance 36 when the extension has shifted over an arc distance sufficient to permit the nose to pass into the clearance, as shown in Fig. 6. A coiled spring 43 of steel wire has one end anchored to pin 44 on the member 11 and has its other end secured to the other arm 45 of the pawl which projects rearwardly towards the pin 44. The spring is biased to maintain the nose of the pawl pointing towards the pin 13 and to locate it in either of the clearances 36 or 38 when clear of the ratch. The pawl is dimensioned and mounted so that the distance measured between the axis of the pins 13 and 40 will be slightly less than the sum of the radial length of the extension measured from the axis of pin 13 to the ratch 35 plus the length of the nose 42 of the pawl. In this way, when the nose is engaged by the ratch when moving clockwise as shown in Fig. 5, the pawl swings on its pivot in the direction of movement of the ratch, but cannot move in the opposite directron.

The several parts are so dimensioned and organized that when the toggle has almost reached its dead center position as shown in Fig. 6 the shiftable jaw 18 is at that instant in its point of nearest approach to the fixed die 17, and the stop wall 37 is engaging the fixed stop pin 46 on member 11. At this time the nose of the pawl is idle in the rear clearance and is held idle by reason of the tensioned spring 43. Likewise, when the jaws are in their fully open position, or almost so as shown in Fig. 4, the ratch has swung counter-clockwise clear of the pawl and the nose of the pawl is similarly held by spring 43 idle in the clearance 38.

In operation and assuming that the wires C are properly located in the sleeve S to be crimped; that the handles have been separated to open the jaws sufficiently to receive the sleeve inserts, the assembly of sleeve and wires so formed is inserted in whichever of the nests it is intended to fit and in the case illustrated the insert is located in the lowermost and largest nest of the three nests illustrated. At this time the toggle is broken and the interlock formed by the pawl and ratch interlock is inoperative as shown in Fig. 4.

As the handles are forcibly brought together the toggle begins to straighten, its knee at pivot 32 begins to elevate from the position shown in Fig. 4, and the shiftable jaw begins to squeeze the sleeve between the jaws of the clamp. As the sleeve begins to be deformed the ratch moves clockwise across the nose of the pawl, swinging the same slightly in a counter-clockwise direction against the tension of the spring 43.

The pawl operates so long as it is thus being ratcheted across the teeth forming the ratch 35 to resist any effort of the extension and the parts connected thereto including the shiftable jaw from moving in an opposite or retreating direction from left to right, and this condition persists until the extension has travelled a distance sufiicient to permit the nose of the pawl to escape into the clearance 36 as indicated in Fig. 6. The parts are so proportioned that at that distance when the shiftable jaw has reached the point of nearest approach to the fixed jaw stopped by the pin 46 the toggle has almost reached its dead center position and the nose of the pawl escapes the ratch, thus finally unlocking the interlock. The pin 46 carried by the member 11 includes a sleeve 46'. The thickness of the sleeve in use at any one time provides a refined means for controlling the thickness of the finally crimped sleeve C as shown in Fig. 6. When the desired deforming of the sleeve has thus been attained the handles are separated into an open position to permit the removal of the finished fitting and the insertion between the open jaws of a new assembly is now permitted. During this opening movement of the tool with the ratch moving counter-clockwise from the position of the shiftable jaw as shown in Fig. 6 the pawl idly sweeps or ratchets back across the teeth of the ratch until it is again in its idle, inoperative and unlocked position with its nose in the space 38 as shown in Fig. 4.

It is not intended that the device be changed by the workman operating the same from its setting as fixed by the manufacturer, and for this reason the device is intentionally made without any easily manipulated adjustment which might facilitate any modification of the preset location of nearest approach.

Except for the restraint by the interlock while the shiftable jaw is on its working stroke, the body 11 and the actuating lever 12, together with the jaws associated therewith, are free for relative movement, and the body and lever being free from any biasing springs, they will maintain any position to which they may be shifted.

It is noted that the pins 13 and 40 are rugged and are permanently fixed relative to each other by reason of the engagement of their ends fixedly in the rugged cheek plates. These plates are designed to have a material depth dimension and thus tend to resist any possibility of the pins shifting relative to the frame even under the powerful operating forces present, which forces might otherwise tend to shift the axes of the pins and especially the axis of the main pin 13. As above noted, the axes of the toggle pins 13, 32 and 33 must not shift, otherwise the carefully pre-set position of nearest approach of the shiftable die to the fixed die would not be retained as initially set by the lengths of the connecting links 19.

Making the ratch element of the interlock as an integral part of the actuating handle contributes to the ruggedness of the power transmitting parts about the pivot pin 13 without necessity of adding material for this purpose, and the housing of the interlock between the rugged cheek plates tends to protect it against accidental damage. It is particularly noted that the number of pivots has been reduced to a minimum and even those areof large diameter and thus capable of distributing strains thereon over extensive bearing areas in the rugged cheek plates. The sleeve is free of small parts which might get out of order.

Difierent operators grasp tools of the pliers type at different places along the lengths of their handles. The present disclosure features the space between the handles left free of any obstruction almost up to the main pin 13 so that the operator can wrap his fingers about any place along the length of the handles most convenient to him.

I claim:

1. In a crimping tool of the pliers type for use in deforming a tube into binding engagement with conductors therein by squeeze pressure, the combination of a main body, a pair of crimping dies, one die constituting a fixed jaw and the other die constituting the shiftable jaw of a squeeze clamp, and end of one jaw disposed within the main body in overlapping relation to an end of the other jaw and a single pin carried by the main body, passing through the overlapping ends of the jaw and forming an anchor'for the overlapping end of the fixed jaw and a fulcrum for the shiftable jaw and toggle means reacting between the main body and the shiftable jaw for rocking the shiftable jaw about said pin as a fulcrum in directions to and from the fixed jaw.

2. In a device of the class described, the combination of a rugged body provided with the fixed jaw element of a crimping clamp, a coacting shiftable jaw carried by the body, a three-arm lever, a pivot pin carried by the body and about which the lever rocks, one arm of said lever constituting a handle, means connecting another arm of the lever with the shiftable jaw to move the same to and from the fixed jaw, and a one-way interlock housed within and thus protected by the body and operative between the body and the third of the three arms of the lever to restrain the rotation of lever in one direction while permitting the rotation of the lever in the reverse direction.

3. A crimping tool including a body portion provided at one end with a relatively deep head forming the fixed aw of a crimping clamp and with its other end reduced in width and forming a handle, a coacting shiftable jaw carried by the body portion, a pivot pin fixed to the head, toggle-forming means largely located in the head and including a lever fulcrumed to the pin and operatively connected to the shiftable jaw to move the same to and from the fixed jaw, stop means limiting the advance of the shiftable jaw and thus the nearest approach of the jaws to each other at the point where the toggle-forming means has almost but not quite reached its dead center position, and a full-stroke compelling mechanism operatively related to the toggle-forming means, to the shiftable jaw and to the fixed jaw for permitting the relative approach of the aws and for defeating relative separation of the jaws prior to the operation of said stop means, and said fullstroke mechanism operative when said stop means has functioned to permit the retreat of the shiftable jaw from the fixed jaw.

4. The tool defined in claim 3, wherein the full-stroke compelling mechanism is housed within and protected by said head.

5. A tool of the pliers type for use in crimping cylindrlcal metal sleeves and the like, said tool including a rigid body portion provided at one end with the fixed aw of a crimping clamp, said fixed jaw having a work face provided with at least one crimping recess and sald body portion providing at its other end a handle extending at right angles to the work face, a coacting shiftable jaw carried by the body portion for movement to and from the fixed jaw. a fixed pivot pin carried by the body portion, toggle-forming mechanism for operating the shiftable jaw and having one element thereof pivoted to the fixed pin and said mechanism including a lever provided with an integral plate-like extension and with a handle cooperating with the first-named handle to operate the tool, the toggle mechanism and the shiftable jaw forming a chain of connected movable parts, the toggle mechanism when moving on its operative stroke and at the point where it has almost but not quite reached its dead center position defining a full stroke limiting position, and a full-stroke compelling mechanism housed within the body portion and including a line of teeth formed on an edge of said plate-like extension of the lever and forming a ratchet, and a spring-loaded pawl carried by and housed within the body portion, across which pawl the ratchet moves in operatively controlling said chain of parts and with the ratchet related 7 to the pawl to escape therefrom and thus be removed from control of said chain of parts at the instant the toggle mechanism reaches its said full stroke limiting position.

6. A crimping tool including a one-piece rigid body portion one end of whichisrelatively de'ep'to provide a rugged box-like structure, said deep end formed of a pair of transversely spaced-apart cheek plates integrally connected at their opposite ends and forming therebetween a narrow mechanism-containing space and the other end of which body portion is reduced to form along, inflexible handle, at least one of the cheek plates provided with a side opening spaced fromthe adjacent end: of the body portion, a fixed die=carried by the body portion at said adjacent end and having its work-engaging face exposed to view through the side opening and with said work-engaging face extending in a plane at right anglesto the length of the tool, a shiftabledie carried by the body portion and mountedfor movement to and from the fixed die, two spaced-apart pins having their ends mounted in the cheek plates and extending across said space, a linkage connected to said shiftable di'eiand carried by one-of the pins located largely in said mechanism-containing space and including a rigid lever, said lever provided with a-lo'ng handle: projecting out of said space and cooperating withth'e first-named handle to operate the tool, the space between the handles at all times being free of obstacles, a full-stroke compelling mechanism located in said mechanism-containing space, housed between the cheek plates and offset from the s'ideop'ening, said mechanism including an extension from the leverprovided along one edge with a line of teeth. forming a ratchet, and a spring-loaded pawl pivoted to the other pin and across which pawl the ratchet moves, said pawl operative'topermit the lever to move on its operative stroke after it has started on such stroke and to prevent movement in the opposite direction and said lever operat'iveto continue its movement in the direction 'of its-work stroketo a position to escape the pawl.

Reir'e'ren'ces Citedin the file of this patent UNITED STATES PATENTS Number Name Date Re. 6,146 Corbett Nov. 24, 1874 465,959- Yerdon Dec. 29, 1891 929,868 Mueller Aug. 3, 1909 1,168,999 Branham Jan. 18, 1916 1,343,893 Bjornlie June 22, 1920 1,711,718 Bierly May 7, 1929 1,714,387 Martinet May 21, 1929 2,088,054 Crosman July 27, 1937 2,207,223 McGary July 9, 1940 2,280,005 Petersen Apr. 14, 1942 2,411,838 Swengel Nov. 26, 1946 2,533,817 Koskinen Dec. 12, 1950 2,577,199 Klopner Dec. 4, 1951 2,583,625 Bergan Jan. 25, 1952 2,618,993 Carlson Nov. 25, 1952 2,627,769 Anderson et a1. Feb. 10, 1953

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