US2962807A - Impact tool for making connections - Google Patents

Description

Dec. 6, 1960 K. M. HAMMELL IMPACT TOOL FOR MAKING CONNECTIONS Filed March 8, 1954 lag INVENTOR.

Kemper M. Humane IMPACT TooL FOR MAKING CONNECTIONS Kemper M. Hammell, Harrisburg, Pa., assignor to AMP Incorporated Filed Mar. 8, 1954, Ser. No. 414,602

1 Claim. (Cl. 29-254) The present invention relates to improvements in methods of and tools for making an electrical connection between an electrical terminal and a contact wherein one part provides a recess which receives and frictionally engages a plug portion of the other part.

One known type of such a connector includes a tapered plug terminal, or the like, adapted to frictionally engage a receptacle contact member, usually with one or the other of said members in fixed position. This type of connection is advantageous, particularly where many lead wires are to be attached in a small area. However, there remains a risk that operators may make such connections carelessly so that the connection may be less than perfect even where the connector parts are properly designed and accurately made.

An object of the present invention has been to provide an implement or tool for connecting these parts in a manner to insure optimum mechanical and electrical engagement between them without injury to or impairment of either.

A further object has been to provide a tool by which one part, as a terminal attached to wire end, may while held by the tool be teleseoped and frictionally engaged with a receptacle contact member quickly and securely in a simple operation even where the available working space is limited and the parts are not otherwise readily accessible.

It is also an object of the invention to provide an attaching tool affording substantially uniform optimum frictional connections for any given type or size of terminal, in part by automatic control of the maximum locating force applied to the part by a given type of tool, and in part by predetermining the energy applied to drive home the terminal after locating it by controlled force.

A further object of the invention has been to provide a method and a tool whereby, in operation, a tell-tale marking, or the like, is left on one of the parts automatically, thus indicating that they have been joined under optimum conditions for producing an effective and durable connection.

In the method according to the present invention of effecting interengagement of connector parts, one of said connector parts is fitted into an appropriate tool and the tool pressed axially to give initial telescoping engagement of said parts; and advantageously, the parts are driven into final frictional engagement, with high radial pressure, by an impact of predetermined magnitude. During the initial inserting operation the tool advantageously cushions the applied pressure and applies a driving force having the requisite direction and magnitude to bring the connector parts into mating relation; and advantageously when a predetermined force for initial insertion has been reached, the tool automatically applies the predetermined energy to drive the parts into final contact relation and, if desired, leaves a mark on one of them.

A convenient form of hand tool according to the present invention includes a handle and a shank (somewhat like an ordinary screw driver) the end of the shank being formed to receive and engage a terminal connector for axial push and to accommodate a wire extending from the back end of the terminal. For more precise insertion, my invention provides a tool comprising a spring-pressed plunger and a hammer mounted for longitudinal movement in a holder, said plunger having a terminal-engaging socket or groove at its outer end for accommodating a Wire attached to the terminal, and means for engaging a spring through which it engages with said holder and is pressed by said holder into initial engagement with the terminal, and a hammer actuating spring is: compressed or loaded to a predetermined extent by initial inward movement of the plunger and the hammer is then released to deliver a driving blow through said plunger to the part initially engaged therewith. Where the driving face of the plunger carries an appropriate die or dies, this blow also leaves a mark on the connector.

Other objects and important features of the invention to which reference has not been made hereinabove will appear in the following description and claims.

Although in the accompanying drawings I have shown a preferred embodiment of a tool according to my in-. vention and have described the same and modifications thereof and of the method according to my invention in this specification, it is to be understood that these are not intended to be either exhaustive or limiting of the invention, but on the contrary, are chosen for the purposes of illustrating the invention in order that others skilled in the art may fully understand the invention, its principles and the application thereof, and that they may embody it and adapt it in numerous forms, each as may be best suited to the requirements of its particular use.

Figure l of the appended drawings is a central longitudinal sectional view of a plunger, hammer and spring assembly in a holder with the outer end of the plunger broken away;

Figure 2 is a view in perspective on enlarged scale of the socket or grooved end portion of the plunger;

Figure 3 is an outer end elevation of the socket portion of the plunger shown in Figure 2;

Figure 4 is a fragmentary bottom plan view of the socket portion of the plunger shown in Figure 2;

Figure 5 is a fragmentary top plan view with the socket portion of the plunger shown as about to engage the shoulder of a receptacle type terminal; and

Figure 6 is a view similar to Figure 5 of the socket portion about to engage the shoulder of a plug type terminal.

Although, as suggested above, the invention may be embodied in a simple screw-driver-like tool, e.g., by rigidly securing a suitable head on a shank or hand grip, the present invention is advantageously embodied in a hand tool which utilizes the operating mechanism, as in Figure 1, of a commercially available self-triggering nail set or center punch-but with the outer end of the operating plunger specially designed and constructed as shown in Figures 2, 3 and 4 and hereinafter described. For more accurate control over the inserting force, e.g. for a taper pin connector, or receptacle, the terminal-engaging plunger of the tool may advantageously push against a spring-driven hammer to load its spring to a predetermined extent, whereupon the hammer is released to be actuated by the loaded spring and impact against another part of the plunger.

As shown in Figure 2, a tool according to the present invention includes a shank 1 which provides a terminalengaging socket or groove 2 open at its outer end. The outer end of groove 2 presents a flared opening defined in part by inclined driving faces 3 each of which has a marking die 4 extending beyond its surface. Groove 2 is advantageously formed at its upper end with a rounded tapering surface 5 providing a guide way for a wire 6 to Patented Dec. 6, 1960 which is attached a terminal, as 7, Figure 5, or 8, Fig ure 6.

When used for connecting a terminal and a receptacle, the terminal is positioned with its insulation engaging portion engaged in groove 2 and with its shoulder portion 11, 11a between driving faces 3 and dies 4. The wire 6 extends thence into and along groove 2.

When the tenninal and its wire are thus engaged in groove 2, the outer end of the terminal is engaged with a contact, as plug 12 or receptacle 12a, which are telescoped together with the necessary force applied by manual pressure on the tool handle, or by impact, or both.

Such a tool with a rigidly connected handle or holder and with agroove as described, enables a careful skilled operator to make consistently perfect connections. In ordinary manufacturing, however, less skilled and less careful operators must be employed for such work. A further improvement. of my invention assures proper connection even with such operators. To this end the grooved end. portion of shank 1 above described and shown in Figure 2 is conveniently incorporated in or mounted on a plunger 13, Figure 1.

A holder 14 for plunger 13, as shown, is made in three sections threaded together and has a central longitudinal bore accommodating at its open end the plunger 13 pushed toward its grooved end by a spring 15. A hammer 16 is slidably mounted in the opposite closed end of said boreand is pushed toward the plunger 13 by a spring 17. A plug 18 screwed into the bore in the lower part of holder 14 serves as an abutment for spring and has acentral opening 19 serving as a bearing to hold plunger 13 toits axial position during sliding movement.

The middle section of the holder 14' between said lower section and the closed end section, has a bore which decreases in diameter toward the upper end so that an annular, sloping cam surface 20 is formed therein. The hammer 16 is of a diameter slightly less than the narrower portion of the bore so that it may slide freely therein. An annular flange 16a at the lower end of said hammer has a free sliding fit in the lower or larger portion ofsaid bore, the lower end of the hammer having a central hole 16b.

, Hammer 16 also has a transverse recess 21 (Figure 1) which receives a slidable detent 22 provided with an axial hole 23 slid'ably fitted to the upper shaft of plunger 13. A flat spring 24, secured to one side of hammer 16 in recess 25, is arranged with its free end extending into recess 21 and bearing against one side of detent 22 which is thus pushed toward the opposite side of the bore in holder 14 as shown in Figure 1. The other end of de tent 22 is rounded and extends radially beyond the opening of recess 21 to ride on the inner surface of said bore in holder 14.

The inner end of plunger 13 extends through the hole 165 in hammer part 16 and may have an end projection 26 of reduced diameter extending beyond a shoulder 27 which normally engages the detent 22 while said projection 26 extends into hole 23 of said detent.

In operation, when pressure is applied to holder 14 in the direction of the arrow (Figure 1) and a wire with a terminal thereon is engaged in the socket (as seen in Figure 6, for example) terminal 8 freely enters contact receptacle 1211. When, with further inward movement of. terminal 8', the frictional contact between said parts increasessufficiently, plunger, 13 is moved inwardly compressing spring 17, the inner end of said plunger being pressed against detent 22 which moves hammer 16 upward against said spring 17. When this movement of hammer 16 brings the rounded end of detent 22 against shoulder. 20, said detent is moved transversely against resistance of spring 24 until'its hole 23 is lined up with plunger 13; and thus it is dislodged from shoulder 27.

. The hammer when thus released is driven downward by spring 17 to deliver a sharp blow when the upper end of plunger 13 strikes the inner end of the bore 16b in the hammer. The energy of this impact is predetermined by the characteristics of spring 17 and the depth of holes 23 and 16b. The force exerted for initial seating of the terminal before the impact occurs is predetermined by the location of cam shoulder 20 and the characteristics of spring 17 (i.e., the loading of the spring at the point where the hammer is triggered for impact). When impact occurs, the operator knows that the inserting operation is complete. The mass of hammer 16 and the power factor to be supplied by springs 15 and 17 will be designed for optimum degree of insertion for a given type and size range of terminals and contracts to be connected. This device is particularly advantageous with terminals and receptacles of the general kind disclosed in the application Serial No. 400,996, filed December 29, 1953.

Where marking of the connector part is involved, the character of the dies 4 will be such as to, leavea sensible mark on the material of the struck part by a blow which effects optimum connection between the parts;

From the foregoing it is apparent that the terminal connecting and marking tools described above are well suited to attain the ends and objects herein directly and indirectly set forth; that they can be manufactured by conventional techniques; and that the various features and arrangements of parts can be modified readily so as best to suit a particular use. Certain features of the dis closure may be used to advantage in particular applications without a corresponding use of other features, and the disclosure may be used to advantage in particular applications without a corresponding use of other features, and the elimination or modification of such features is to be construed as within the scope of this invention unless specifically excluded by the following claim or required by the scope of the prior art;

I claim:

For use in installing a connected lead wire and tapered connector having lateral driving abutments intermediate its length in mechanically-wedged electrical connection with a mating connector part, a tool including a plunger mounted to slide endwis'e inwardly in a recessed handle initially to load a spring enclosed therein and means for impact driving said plunger in the opposite direction when said spring is released from loaded condition after predetermined inward movement of said plunger, the outer part of said plunger relative to said handle providing an axially extending shank having an axially disposed longitudinal connector-engaging groove therein, said groove at one end opening through the end of said shank to define divergent driving faces at the end surfaces of the groove sidewalls adapted to drivingly engage said abutments, and a guideway at the other end of the groove adapted for engaging a connected portion of the lead wire of the connector whereby the connector and adjacent lead wire portions are maintained in axial alignment along said shank in position for installation with the lateral driving parts abutted against said driving faces.

References Cited in the file of this patent UNITED STATES PATENTS 1,444,231 Berge Feb. 6, 1 923 1,720,318 Chisholm July 9, 1929 1,882,689 Abertson Oct. 18, 1932 1,903,548 Kreis Apr. 11, 1933 1,958,329 Beard May 8, 1934 2,462,774 Pollock Feb. 22, 1949 2,509,932 Leeth a May 30, 1950 2,521,186 Pennella Sept. 5, 1950 2,635,328 Larmour Aug. 21, 1953 2,686,963 Freyssinet Aug. 24, 1954 2,774,133 Sitz Dec. 18, 1956

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