US2320493A - Clamp - Google Patents

Description

June 1,1943. F C, WALLACE '2,320,493

CLAMP Filed Jam 9' 1942 Patented June 1, 1943 CLAMP Frank C. Wallace, Los Angeles, Calif., assigner, by mesne assignments, to Herman H. Helbush,

Beverly Hills, Calif.

Application January 9, 1942, Serial No. 426,228

7 Claims.

This invention has to do with clamping tools and more particularly it relates to clamps used to temporarily hold superposed or overlapping perforated sheets together with their perforations in register to facilitate riveting. This present invention concerns improvements in the retaining members employed in such clamps as are described and claimed in my copending application Serial No. 417,813, led November 4, 1941, and has for one of its principal objects the provision of a clamp embodying a retaining member which may be installed and assembled with minimum time and effort and which, when assembled remains securely in position.

These clamps are used by the hundreds of thousands in the airplane industry and necessarily must be capable of being manufactured economically and yet be sufcently durable to withstand hard usage. For instance, in the clamp of my said copending application the spreader member employed to spread apart the legs of the retaining member must be inserted from within the cylindric clamp body during assembly and the enlarged outer ends of the legs must be passed through the relatively small opening in the body and wall before the spreader is inser-ted. At the same time it is desirable to have the opposite ends :of the legs headed to prevent the operating plunger in which the legs are mounted from escaping outwardly from the body and separating from the legs of the retaining member. This situation presents material assembly difficulties unless it is possible to install the plunger after inserting the retaining member and spreader through the relatively small hole in the end wall of the clamp body and after inserting the retracting spring into the body yaround the retaining member. While I have shown one way of accomplishing this in my said eopending application, I have found that the improvements of this present application materially facilitate manufacture and assembly and also provide an extremely durable construction.

Still further objects and advantages are inherent in my invention and how those as well as the foregoing are attained will be made apparent from the following detailed description of a presently preferred adaptation thereof, for which purpose I refer to the accompanying drawing, in which:

Fig. 1 is a side elevation showing the clamp in course of being applied to the work;

Fig. 2 is a longitudinal sectional View show- .ing the device in clamping position;

Fig. 3 is an end View taken on line' 3-3 of Fig. 2; and

Fig. 4 is a section on line 4-4 of Fig. 2.

Referring now to the drawing, the numeral 5 designates a cylindric body having an annular ilange 6 at one end to be engaged by a clamp applying tool, not shown, and having an end wall l provided with a central opening 8.

A plunger I0 having a central longitudinal bore and a reduced diameter inner end I5 is slidably mounted in the bore of the body, a coil spring Il being interposed between the inner end of the plunger and the insert member to be hereinafter described, the spring embracing the reduced diameter portion l5 of the plunger.

A tubular insert 2D extends through opening S, this insert having an enlarged diameter cupshaped inner end 2| which rests inside the body against the inner surf-ace of end wall-1, being rotatable with respect to the body.

A retaining member comprised of parallel elongated legs 30 headed at their inner ends 3| and having enlarged outer ends 32 is slidably mounted in the body so that the enlarged ends 32 may be protracted and retracted with respect thereto so as to be inserted through registering perforations P in superposed sheets S for the applying and clamping operations as more particularly described in my said copending application. A T-shaped spreader is positioned between the legs 38 to diametrically spread them apart as the legs slide with respect to the spreader. This spreader has a cross yarm portion 40 which rests within the recess 22 provided in the inner end 2| of the insert and has a central arm 4| which projects through opening 8 between legs 2G to a point spaced outwardly from .the outer end of the insert 20. A washer 44 is interposed between the inner end of spring |1 and the inner end 2| of the insert, the legs 3|! slidably passing :through the central hole 45 in the washer. Thus while Ithe spreader arm 40 is free to rotate eoaxially in the recess 22, it is held against longitudinal movement between this washer and the insert. A dimple 4l is provided on the outer surface of the end wall around hole 8 whereby to engage in the countersink C of perforation P.

To assemble my device, the insert 20 is rst inserted through the body bore, after which the e retainer legs 30, with the washer 44 therearound and positioned adjacent the headed end 3|, are inserted. Next the spreader is inserted and the washer pushed down against the inner end of the insert, after which the spring I1 is inserted in the.

body around the legs 21'). Then the plunger l0 is inserted against and somewhat compressing the spring, the headed ends 3l of the retaining legs passing upwardly through the bore l l of the plunger until they reach the countersunk end ma of the plunger. I then secure the retainer legs in the plunger by inserting a bar 50 between the headed ends of the legs, which acts to spread the headed ends 3l diametrically apart to cause them to engage in the countersink Ilia and prevents the spring from forcing the plunger outwardly with respect to the retaining legs.

When thus assembled the plunger is held against escape from the body by means of the enlarged ends 32 of the legs engaging against the cuter end of the insert 29, when the device is in inoperative or non-clamping position, or by the enlarged ends 32 engaging against the sheet S farthest from the body end wall 1 when the device is in clamping position (see position of Fig. 2).

While I have resorted to considerabledetail for the purpose of making my invention understood, I wish it understood that'within its broader scope, as defined by the appended claims, various modications and adaptations may be made without departing from the spirit of the invention.

I claim:

1. In a clamp device, the combination of a body, a plunger slidably mounted therein, said plunger being provided with a bore, a retaining member slidably mounted in the body, the inner end of the retaining member being longitudinally split and disposed longitudinally of the bore in the plunger, and means for securing the retaining member in the plunger including a separator inserted in vthe longitudinally split'end of the retaining member.

2. In a clamp device, the combination -cf a body, a plunger slidably mounted therein, said plunger being provided with a longitudinal bore, the bore having an enlarged diameter portion, a retaining member slidably mounted in the body and being protractable and retractable at its outer end with respect to the body, the inner end of the retaining member being disposed longi tudinally of the bore inthe plunger and presenting a lateral projection, andan -insert in the plunger engaging the inner end of the retaining member whereby to engage said lateral projection in said enlarged diameter portion.

3. In a clamp device, the combination of a body, a plunger slidably mounted therein, said plunger being provided with a longitudinal opening therethrough, a retaining member having a split inner end mounted in said longitudinal opening, and means spreading the inner end of the retaining member into engagementI with the side walls of the opening whereby to secure the inner end oi the retaining member against longitudinal movement with respect to the plunger.

4. In a clamp device, a cylindric body, a plunger slidably mounted in the body, said plunger being provided with a longitudinal opening therethrough, a countersink in the opening, an elongated retaining member disposed longitudinally of the body, the inner end of the retaining member presenting parallel legs disposed longitudinally in said opening and each having a headed portion, means disposed between said legs and diametrically spreading them apart whereby to engage said headed portions in said countersink, and a spring in the body, said spring bearing against the plunger in a direction to resiliently resist longitudinal escape of said headed portions from said countersink.

5. In a clamp device, the combination of a body, a plunger slidably mounted therein, said plunger being provided with an opening countersunk at its outer end, a retaining membercomprised of spaced parallel legs mounted longitudinally of the body, the inner ends of said legs being disposed longitudinally in the opening through the plunger and having headed portions adapted to engage in said countersink, and lan expander bar inserted between said headed 'portions whereby to expand them into engagement with the side walls of the countersink.

6. In a clamp device, the combination of a body, a plunger with an opening countersunk at its outer end slidably'mounted therein, a retaining member Ycomprised of yspaced parallel legs mounted longitudinally of the body, the inner ends of said legs being disposed longitudinally in the opening through the plunger and having headed portions adapted to engage in said countersunk end whereby to expand them into engagement with the side walls of the countersunk opening.

'7. In a sheet metal fastener having a thimbleshaped body the closed end of which is centrally perforated, a plunger comprising apair-of ngers seated in the body perforation, a shouldered sleeve encompassing the `inner end of the p1unger, and means for spreading the iingers so as to lock them in position Within the sleeve.

FRANK C. WALLACE.

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