US3030831A - Design and construction of jigs and fixtures - Google Patents

Description

I 1962 J. WHARTON 3,030,831

DESIGN AND CONSTRUCTION OF JIGS AND FIXTURES Filed Nov. 5, 1959 I A ttorney\ United States Patent Ofitice fiddfifi Patented Apr. 24, 1962 3,030,831 DESIGN AND CQNSTRUCTION F JIGS AND FIXTURES John Wharton, 151 London Road, St. Alhans, England;

Alice Mary Wharton, .executrix of said John Wharton,

deceased, assignor to Wharton & Wilcocks Limited,

Hertford, Hertfordshire, England Filed Nov. 3, 1959, Ser. No. 850,737 1 Claim. (Cl. 7762) This invention relates to the design and construction of jigs and fixtures.

In the specification to Patent No. 2,676,413 there is described and claimed a jig or fixture for use in the manufacture and production of component elements to accurate dimensions, such jig or fixture being built up of a multiplicity of interchangeable standard elements each furnished with one or more T-slots, or one or more tenon slots, or one or more tenons or any combination of T- slots, tenon slots or tenons adapted to locate and secure the said standard elements relatively to one another and to a base or to a frame or frames attached to said base, on which they are mounted and secured to form a complete unitary structure.

For a drilling operation on a component, a fixture constructed in accordance with the disclosure of the aforesaid specification may, for example, comprise a base member having fixedly mounted thereon a so-called stop element. Tenoned to the upper end of the stop element is a rectangular block having upstanding lugs at each corner adapted to guide the stem of a clamping member for holding a drill bush or the like, said stem being flat and having therein an elongated slot through which passes a securing bolt, the latter passing up from the base member and also through the stop element and guide block, a locking nut being engaged with the upper or outer end of said bolt and turned until it firmly secures the stem of the clamping member to said block. Normally a clamping plate or the like is arranged between the locking nut and the stem of the clamping member.

The provision of the elongated slot in the stern of the clamping member enabled the position of the clamping member with respect to the supporting guide block to be adjusted as required. The rigidity of these parts after adjustment, however, depends largely on the friction between them due to bolting, and it is possible for the proper adjustment thereof to be upset, for example, by a sharp accidental blow. The present invention has for its main object to provide improved means for overcoming this disadvantage.

In the accompanying drawings:

FIG. 1 shows an arrangement as heretofore proposed, and

FIG. 2 shows an arrangement in accordance with this invention.

With reference to FIG. 1 of the accompanying drawings, which shows an arrangement as heretofore proposed, there is shown or indicated therein a base member I having fixedly mounted thereon a stop element 2, as described in the Specification to the aforesaid patent. Tenoned to the upper end of the stop element is a rectangular block 3 having upstanding lugs 3 at the corners thereof adapted to guide the stem of a clamping member 4 for holding a drill bush or the like 5, said stern being flattened and having therein an elongated slot 6 for the passage of means (described in detail hereinafter) for securing it to the guide block.

In the arrangement shown in FIG. 1 a single securing bolt (not actually visible) passes up from the base memher 1 through the stop element 2, the guide block 3 and the slot in the stem of the clamping member 4, a locking nut 7 being engaged with the upper or outer end of said bolt and turned until it firmly secures the stem of the clamping member to the guide block. A clamping plate 8 is disposed between the locking nut 7 and the stem of the clamping member.

The clamping member 4 is provided at the end thereof remote from the bush holder 5 with a downwardly directed plate 10 disposed in a plane parallel to the end face of the supporting guide block 3, said plate having therein an aperture or slot which is arranged in line with a tapped hole in the supporting guide block. A threaded rod 11 is engaged in said tapped hole, being secured by a locking nut 12, and passes freely through the aperture or slot in the plate It). Thus when the position of the clamping member 4 is being adjusted the plate 10 slides over the rod 11, locking nuts 13 being provided on the latter for engaging the opposite sides of the plate and so locking it and the clamping member in any desired correctly adjusted position.

In the arrangement in accordance with this invention, as shown in FIG. 2, instead of the single screwed rod 11 as described above, there is provided a pair of parallel spaced rods 20 which extend from a plate, not visible, attached to the guide block 3 by holding screws, and on each of these is mounted a plurality of cylindrical members or discs 21 of known accurate dimensions, these members or discs being separated by spacers, also of known dimensions but of smaller diameter whereby annular slots 22 are provided between the adjacent members or discs 21. The cylindrical members or discs 21 with the spacers between them are secured on their respective rods by nuts 23 engaging the ends of the latter. The plate ltl on the clamping member 4 is provided with apertures 24 through 7 which the cylindrical members or discs can freely pass and pivoted to the plate is a plurality of levers 25each of which has an edge portion 25 of the same thickness as the spacers, the arrangement being such that this edge portion can be engaged in the slots 22 between the cylindrical members or discs on one of the rods. The slots 22 between the cylindrical members or discs on one rod are staggered with respect to those on the other, one lever 25 being associated with each rod. Such arrangement provides a range of fixed settings for the clamping member 4, any one of which can very readily be adopted.

I claim:

A jig or fixture built up of a plurality of interchangeable standard elements comprising a base having a flat upper surface with a plurality of T-slots extending lengthwise in the upper face of the base, a stop element comprising a rectangular block having a square horizontal cross section, a tenon on the under surface of said block, a tenon slot in at least one other surface of the block, means for securing the stop element on the base with the tenon there on located in a T-slot in the base, such means comprising a bolt engaged in the T-slot in the base and passing through the stop element perpendicularly to said tenon, and a locking nut cooperating with said bolt, a guide block mounted on the outer surface of said stop element, means for engaging said guide block in the tenon slot in the stop element positively to locate the guide block against turning, spaced guide lugs on said guide block, a clamp memher, for holding a drill bush, adjustably mounted on the guide block being slidably engaged by and between said guide lugs, the said securing bolt passing also through the guide block and clamp member whereby they, together with the stop element, are secured to the base, a plate secured to one end of said clamp member and extending at right angles thereto, rod means fixed in said guide block and extending therefrom in parallel relationship with the clamp member, a plurality of discs mounted on said rod means, spacer elements also mounted on said rod means and separating said discs one from the other, said rod means with the discs thereon extending through an aperture in said plate, a locking lever pivotally mounted on said plate and adapted selectively to be engaged in the space between any two of said discs thereby to ensure rigidity between the clamp member and the guide block after the clamp member has been adjusted to any desired position.

References Cited in the file of this patent UNITED STATES PATENTS Wharton et al Apr. 27, 1954 OTHER REFERENCES

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