US 2618993 A
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- NOV. 25, 1952 v CARLSON 7 2,618,993
CONNECTOR FORMiNG TOOL WITH RA'ICHET MEANS FOR COMPELLING PRECISE OPERATION Filed Jan. 14, 1948 NVENTOR.
,4 1 M ATTORNEYS.
' or handles.
cure engagement with the wire.
Patented Nov. 25, 1952 UNITED STATES PATENT OFFICE CONNECTOR FORMING T OOL WITH RATCHET MEANS FOR COMPELLING PRECISE OPERATION Vernon E. Carlson, Camp Hill, Pa., assignor to Aircraft-Marine Products Inc., Harrisburg, Pa.
Application January 14, 1948, Serial No. 2,261
together accurately formed dies and the precise extent of their movement under such pressure is important.
A commonly used type of hand tool for attaching electrical connectors to Wires includes opposed crimping dies mounted on jaws at end portions of spring pressed cooperating lever grips In the use of such a tool, the ferrule or wire-embracing portion of a connector is positioned to embrace an end portion of the wire; and this assembly is brought into position with said ferrule between said crimping dies. Manually applied closing pressure on the grips or handle levers causes the jaws to close and the dies to engage and compress the ferrule into se- Such crimping is a precision operation in which both the dies and the connector units to be crimped therein are held to very close tolerances. Unless the jaws are closed together to an accurately predetermined position, the advantage of such precision is lost and the connection between the connector and the wire may be less secure and electrically less perfect than is required. This can result either in rejection of the work on inspection or failure in use.
An object of the present invention has therefore been to provide a tool which, in use, supplies means for preventing release or reopening of the jaws until desired or necessary crimping pressure has been applied to securely fasten the fervrule to a wire or other conductor.
liminary grip before the final crimping. Thus,
in applying the ferrule type solderless connector, it is often convenient to preposition such connector in relation to the tool or otherwise by initial or less than full pressure on the handles.
With simple terminal connectors, this is done by holding the handles lightly gripped with one hand, while the wire or other conductor is inserted into it with the other hand; but in other cases it is necessary to use both hands after such pre-positioning of the connector in the crimping 2 dies, and it is very diflicult to maintain or hold that position manually when the operator finds need to change his grip on the tool handles so as to manipulate a wire end, or for any other reason.
A further object of the invention has therefore been to provide a crimper which incorporates a ratchet device whereby the crimping dies may be held in an initial position resulting before effective crimping.
Further objects and beneficial applications of the present invention will be apparent to those skilled in the art from the following description.
of one form thereof as embodied in a crimping tool and from the appended drawings in which- Figure l is a plan view of a hand operated tool equipped with dies for crimping solderless electrical connectors on portions of electric wires or conductors; the closed position being shown in full lines and a partially opened position of the handles being indicated by the dot-dash lines;
Figure 2, an enlarged fragmentary detail illustrating relative positions of the pawl and ratchet occurring during return movement of the handle levers 0r grips toward open or inoperative position;
Figure 3, an enlarged fragmentary detail illustrating relative positions of the pawl and ratchet occurring when the handle levers or grips have reached full open position and started a closing movement;
Figure 4, an enlarged fragmentary detail illustrating relative positions of the pawl and ratchet during closing or inward movement of the handle levers or grips, the position of the pawl relative to the ratchet rod at two positions nearer to the final fully closed position being shown in broken lines;
Figure 5, a detail view in section on the line 55 of Figure l;
Figure 6, a fragmentary detail view, partly in section, on the line 6o of Figure 5;
Figure 7, a fragmentary view partly in vertical section illustrating a portion of a modification wherein the pawl carrier is adjustably mounted in relation to the ratchet; and
Figure 8, a transverse enlarged section on the line 8-8 of Figure 7.
The hand operated crimping tool shown in Figure 1 comprises a pair of handle grips in the form of grip levers 9 and It pivoted at H and normally biased toward open or spread position by a spring l2. In a tool wherein the grip levers 9 and I0 are approximately ten inches long, for
example, these handles are designed with resiliency, to give to movement at their outer ends by a normal mans grip after the dies are fully closed. These handles as shown are made by die forming them with a generally U-shaped cross-section from sheet steel of about 0.05 inch thickness, or in such manner that when the dies are closed one against the other, further compression applied to the grip levers will cause one or both of them to yieldingly bend for a purpose and under circumstances to be described.
Opposed crimping dies [3 and I4 are carried on jaws or levers l5 and 16, respectively. Jaw lever I5 is pivoted at II to said grip lever 9; and jaw lever 16 is pivoted at 18 to the other grip lever I0. Said jaw levers l5 and J6 are mounted to rock on pivots I9 which-are carriedby tie plates 2| and 22; and a cylindrical key fitted into grooves in jaws l5 and I6, secures them against relative longitudinal movements, and. thus keeps the dies aligned. Other details of construction and the mode of operation-of one form of tool having structural features above described are set forth in my U. S. Patent No. 2,359,083.
The'use of tools of this type for application .of connections in critical parts has sometimes been objected to on the ground that it is possible to make a plausible-looking indentation in the arranged to form a ratchet 23, here shown as a conventional screw thread. An intermediate .portion of said rod is reduced in diameter to form an annular groove 24 at the inner end of ratchet 23 and of suflicient depth to permit the free end of a spring biased pawl 25 pivoted at 26 in a housing 21 to disengage said ratchet and swing freely when said pawl comes opposite said groove 24.
The other end of said rod is also screw threaded and adjustably engages a threaded socket in bracket 28 pivoted to said grip lever 9 at 29. A set screw 30 or equivalent locking device is engaged with said rod and bracket 28 to hold the ratchet rod in a predetermined position of adjustment in relation to said bracket 28. The adjustment thus secured is such that with the ratchet accurately adjusted so that the free end of pawl 25 engages the last tooth at the inner end of ratchet 23 (as indicated in the short dash lines on Figure 4) when the grip levers 9 and I0 have been pressed together to the position of maximum required crimping for the particular connection being formed, and pawl 25 will disengage said last tooth on said ratchet and swing into groove 24 only when said grip levers are resiliently sprung past said position of complete crimping. Pawl 25 will be disengaged from the outer end of said ratchet 23 when said grip levers 9 and ID are extended beyond their position Where initial engagement of the connector occurs.
Said housing 2'! forms part of, or is mounted on, a pawl carrier, shown as a tube 31 open at its inner end and with its other or outer end pivoted at .32 to grip lever 10. The innerend ofsaid ratchet rod which has the ratchet 23 extends into the open end of tube 3| in telescoping relation thereto. In use, when the grip levers 9 and H! are brought to closed position and additionally compressed, as described, the resulting relative endwise movement between the ratchet 23 and pawl carrier 3| brings said annular groove 24 opposite the pawl 25, which then swings to the inoperative position shown in Figures 1 and 6 (full line), where it is yieldingly retained by a spring 33, Figure 6. When the handles 9 and I9 are moved apart to open the tool, the pawl is tilted over the ratchet as shown in Figure 2, and when the handles are moved toward one another the pawl is tilted as shown in Figures 3 and 4.
The device above described provides one embodiment of means whereby a hand tool may be conveniently adjusted and calibrated for use in producing uniformly effective joining or bonding of various sizes and types of electrical connectors to different gauges and kinds of wires. For factory calibration of tools if, as shown, there is a stop on the dies which must be closed, e. g., as shown at 36, to give the required precision crimping, adjustment is made at this position. For tools designed for operating on connectors o a given size applied to wires of a given size and quality, but not provided with such stop, a templet or calibrating gauge is prepared having the precise size and shape of a completed crimp on a given type of connector With a given type of wire. This gauge is placed between the dies [3 and I4 and the grip levers are compressed to move their free end portions one toward the other. If, when the dies 13 and I4 first grip the gauge so that it cannot be moved in the dies. the pawl 25 is beyond the last tooth on the ratchet 23, i. e., beyond the relative position as shown in short dash lines in Figure 4, the adjustment is too loose. When at this stage of the closing the pawl 25 is on or very near the last ridge of the ratchet 23, e. g., as shown in the short dash lines in Figure 4, so that feasible additional flexing of handles 3 and 10 will bring the free end of pawl 25 into groove 24, the adjustment is satisfactory and the adjustable parts will be locked in this relation by tightening screw 30 or by other more permanent means, as by denting to deform the threads, or spot welding, or drilling and driving in a taper pin or a rivet, if desired.
If, under the test conditions stated above, after full normal pivotal closing movement of grips 9 and H], the free end of pawl 25 is still riding on an intermediate portion of ratchet 23, for example, as shown in dot and dash lines, Figure 4, so that it will not disengage said ratchet upon the further compression effected by yieldingly flexing said grips, the position of ratchet'23 in relation to said pawl'is adjusted by rotating the ratchet rod in a direction to move the latter outwardly, or in the direction of the arrow, Figure 4, until pawl 25 occupies substantially the dotted line position, Figure 4, relative to ratchet 23. If this adjustment is correct, the proper further compression, with consequent slight bending movement, of said grips will cause the free end of pawl 25 to disengage from ratchet 23 and swing into groove 24, indicating acceptable calibration.
If under the test conditions stated above, the free end of pawl 25 has already disengaged ratchet 23 and swung into groove 24 prior to the end of the normal pivotal closing movement of grips 9 and 10,- said ratchet rodrotatedto moveit endwise in the opposite direction from .that above described. The extent of this adjusting movement being such that pawl 25 will occupy substantially the dotted line position, Figure 4, relative to ratchet 23.
It is contemplated that relative adjusting movement of the pawl carrier 3! in relation to the ratchet, or adjustment between the pawl and the pawl carrier, or other equivalent adjustment may be employed instead of the adjustment of the ratchet 23 to produce the desired calibrating movement between the pawl and the ratchet with substantially the same or equivalent calibrating efiect as that above described.
Thus, in the modification shown in Figures 7 and 8, one end of the pawl carrier 3m is ad- Justably connected to handle 10 through a bracket 34 pivoted at 32 by a rotatable connector bolt 35. The shank of said bolt 35 is threaded exteriorly to engage an interiorly threaded end portion of said pawl carrier tube 3la. A set screw 30a holds carrier 3m and bolt 35 locked in any desired position of longitudinal adjustment.
The outer end or head of bolt 35 is provided with a central recess 31 intersected by a transverse hole 38. The inner end of bracket 34 has a stud 39 provided with an annular groove 40. The parts are assembled with said stud 39 extending into recess 31 and with hole 38 aligned with groove 40. A pin 4! closely fitted or riveted in hole 38 extends through a portion of groove 40, thus securing bolt 35 to bracket 34 in such a manner that said bolt fits snugly on but is freely rotatable in relation to stud 39 of bracket 34.
When a tool embodying the modification shown in Figures 7 and 8 is subjected to the test procedure previously described, adjustment of the relative positions of the ratchet and the pawl where needed is made by slacking screw 30a and rotating bolt 35 the required number of turns in the desired direction. When calibration is complete screw 30a is tightened, or other equivalent means may be provided to hold carrier 3| and bolt 35 in adjusted relation. From the foregoing it will be clear that calibration may be effected by adjustment of the ratchet carrier, or of the pawl carrier, or of both if desired.
In a typical cycle of use, grip levers 9 and 13 are opened, for example by spring l2, from the closed position, Figure 1. This produces relative endwise outward movement of said pawl 25 and said ratchet 23, during which pawl 25 rides over teeth 23 and is yieldingly tilted in the direction shown in Figure 2. At the end of said endwise outward movement, pawl 25 disengages the outer end of said ratchet 23 and returns to normal position by operation of spring 26.
The term open as used in the appended claims means, of course, that the dies are far enough apart to release the work and permit insertion of other work.
Closing movement of said grip levers 3 and I produces inward movement of said ratchet 23 and, during said inward movement, as the free end of pawl 25 engages and rides upon ratchet 23, said pawl 25 is yieldingly tilted from normal position in the direction as seen in Figure 4. When said pawl 25 comes opposite said annular groove 24, Figure 1, it disengages said ratchet 23 and returns to its original normal inoperative position.
In an illustrative example, after opening the grip levers 9 and of the crimping tool, for example, and partially closing them to such extent that the dies have engaged and are lightly gripping the ferrule or shank of an electrical con- 6 nector, the operator may see that the ferrule and the dies are not in proper relation or that some other condition exists which might prevent making an acceptable joining. The necessary adjustment may require using both hands. In such case, the initial or light gripping effect of the tool may be retained when hand pressure is relaxed, or even if the tool is laid down. In another example, perhaps the operator has pressed the grip levers 9 and [0 as far toward each other as he can on the initial grip, but the amount of crimping so produced is insufl'icient. He can then take a fresh hold and exert the needed additional pressure to complete a satisfactory crimp.
In each of the foregoing examples, relative motion, Figure 4, between the ratchet 23 and pawl 25 has been arrested short of its required minimum extent for the particular work involved. And in each case, the free end of pawl 25 engaging a ridge or tooth of ratchet 23 looks the parts against opening movement of the grip levers 9 and I0 until full closing movement shall have been completed.
It will be apparent from the foregoing description that the present invention provides a tool of which the parts can be made advantageously under normal factory conditions but by reason of its calibrating features may be completed practically as a, precision tool; and that in use, it insures material advantages in rapid operation and the more effective and accurate attachment of solderless connectors to wires or the like.
1. A tool for crimping and the like comprising, levers pivoted together, dies connected to the levers and movable thereby to and from a closed crimping position, stops engaging to prevent further relative movement of the dies after closure to crimping position, said levers having a range of deflection such that their movement toward one another can slightly exceed the relative pivotal movement necessary to close the dies to crimping position, a reversible pawl assembly pivotally connected to one of said levers, a coacting ratchet assembly pivotally connected to the other, the effective length of the ratchet being equal to the sum of the magnitude of the pivotal movement of the levers and the deflection movement of the levers in the die closing direction so that the ratchet overruns the pawl after engagement of the stops and after deflection of the levers to permit the levers to be opened again.
2. A tool for crimping and the like comprising dies, levers pivoted together and connected to said dies to urge the same to and from a closed crimping position, stops mutually engaging to prevent further relative movement of the dies after closure to crimping position, said levers having a range of deflection such that their movement toward one another can slightly exceed the relative pivotal movement necessary to close the dies and engage the stops, a, housing pivotally connected to one of said levers at a point remote from the point of pivotal connection of the levers, a reversible pawl mounted within said housing, a coacting ratchet assembly connected to the other of said levers at a point adjacent the pivotal connection of the two levers, said ratchet assembly sliding within said housing in coacting relation to said pawl, the length of the ratchet being equal to the sum of the magnitude of the pivotal movement of the levers and the deflection movement of the levers in the closing direction so that the ratchet overruns the pawl after closure of the dies, engagement of the stops and defiectionof the levers ,to permit the levers to be opened again.
VERNON E. CARLSON.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Re. 6,146
Number Number Name Date Brassell Apr. 18, 1922 Perry Aug. 25, 1925 Tull et a1. Jan. 5, 1926 Carlson Sept. 26, 1944 Swengel Nov. 26, 1946 Feitl et a1. Apr. 13, 1948 Davis Nov. 23, 1948 FOREIGN PATENTS Country Date Germany Jan.31, 1935 Great Britain Feb. 24, 1947