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Publication numberUS857295 A
Publication typeGrant
Publication dateJun 18, 1907
Filing dateJul 26, 1906
Priority dateJul 26, 1906
Publication numberUS 857295 A, US 857295A, US-A-857295, US857295 A, US857295A
InventorsHenry H Mudge
Original AssigneeHenry H Mudge
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
US 857295 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

No. 857.295. PATENTED JUNE 18, 1907. H. H. MUDGE. Q -120m. APPLIGATIOR FILED JULY 26, 1906. l



Specification of Letters Patent.

Patented June 18, 1907.

Application filed July 26,1906. Serial No. 327.932.

To (LZZ whom, it 7n concern-r Be it known that I, HENRY H. M DGE, a citizen of the United States, residingat Bristol, in the county of Bristol and State of Rhode Island, have invented new and useful Improvements in Bolts, of which the following is a specification.

My invention relates to a bolt adapted to a great variety of uses in drawing or binding together two objects, its construction including a shank tubular throughout, with its lower end fitted to screw into a tapped hole of one of the bodies to be united, while the head of the bolt is conical and also tubular or provided with a cavity preferably of inverted pyramidal form. The bolt head is or may befurnished with a cap, stopper or plug adapted to close the head cavity so as to prevent the entrance of extraneous matter thereto and to the tubular shank, and in consequence to the tapped hole in which the lower end of the bolt fits.

My improved bolt isintended to be screwed into and withdrawn from the inner one of two bodies through the medium of a wrench or turn screw whichfits the head and a cer tain portion of the tubular shank, the bore of which is of square, triangular or other ,polygonal shape in cross section.

I-Ieretofore hollow screws, more particularly set screws, have been known, and I do not broadly claim a screw having a hollow shank capable of receiving a wrench or other instrument for attaching it to or removing it from a threaded body; my invention being shown in the accompanying drawings, described in the explanation thereof which follows, and more particularly pointed out in the claims of invention at the end hereof.

In the drawin Figure 1 shows, partly in section, the hea ed end of a cylinder, such for example, as is used in gasolene driven automobiles to which my invention is applied in the attachment of the head to the cylinder. Fig. 2 is a plan view of Fig. 1. Fig. 3 is a section showing a modification of a fea- 'ture illustrated in Fig.- 1. Fig. 4 shows a modified form of the head of the bolt. Figs. 5 and 6 indicate wrenches or turn screws suited for use with my improved bolt.

Similar reference characters indicate similar parts in the respective figures.

While my invention is here shown as applied to the attachment of a head to its cylinder, it is obvious it is not limited to this special purpose, this mode of use being presented as one simple and conventional in type.

Let 1 re resent a cylinder and 2 its head. The cylin er and head are united as shown by four bolts each of which enters a threaded or tapped hole in the end of the cylinder, and

is constructed as follows: 3 is the hollow bolt the portion from a to b of which is that comprised between the point at which the thread begins and the head. The head 4 is conical and provided with a squared or inverted pyramidal cavity 1 which at the bottom registers and agrees in shape with the aperture or bore 4 through the shank of the bolt. The portion of the latter from b to c is threaded and enters the tapped hole 5 in the end of the cylinder or other part to which the detachable member 2 is to be affixed or drawn.

' In Fig. 1, 6 represents a cap, stopper or plug of shape conforming to that of the cavity 4 in the head 4 of the bolt, but preferably of about one-half its depth and which is fitted to the cavity as shown. In the form of cap seen in Fig. 1, a wall of the cavity 4 is provided witha notch 4 which fits the tongue 7 of a finger lever 7 pivoted at 7 within a slot in the cap as shown, the tongue being prefer ably forced into the notch through the medium of a spring 7. In Fig. 3 a cap 6" is shown a modification having resilient prongs 8 which extend through the cavity in the head of the bolt and engage sides of the bore in the shank. Any form of ca stopper or plug may be employed provide it is adapted to be held within the head and to be readily withdrawn therefrom. i In Fig. 4 the head of the bolt is not conical but rounded and with a flat bearing surface.

In Figs. 5 and 6 two forms of wrenches or turn screws are shown, Fig. 4 indicating one .with a single and Fig. 2 one with a double all torsional strain thereupon being avoided.

The head of the screw constituting this invention being provided with a square or in- 'verted pyramidal cavity, the bottom of upper portion of the wrench or turn screw adapted to fit the cavity in the head conforms to its shape, the wrench is firmly seated in the screw both at the head and throughout the length of the shank, and that in forcing the screw to or removing it from a body the strength of the screw or its head is not impaired. The same advantageous result follows Whether the bore in the shank and the cavity in the head are of other polygonal shape. In all cases the cavity in the head, diminishing in size from the top to the bottom, corresponds in cross section to the shape of the bore of the shank, the sides of the cavity registering with those of the bore.

Ordinarily, in tightening a nut on a solid bolt, if much force is used the bolt is broken and usually where the two pieces of iron bolted together are contiguous. The piece of the bolt remaining in the standing part is removed with difiiculty, it being necessary to drill a hole in the part, and the threads are usually damaged. For example, in-Fig. 1 the ordinary solid bolt would be screwed into the cylinder and the cylinder head bolted on by means of a nut engaging the end of the bolt extending through the registering hole in the cylinder head. When such a bolt is broken the break generally occurs where the bolt enters the cylinder, and when it is drilled out the threads in the hole in the cylinder are apt to be more or less damaged and their holding strength on a new bolt impaired. But if a break occur in my hollow bolt, it is obvious the broken part may be easily removed without taking the engine apart. Such constructions as these render my improved bolt valuable in many ways.

I do not restrict myself to the exact details of construction, combination and arrangement herein set forth, it being obvious that minor variations thereof, not involving the exercise of invention, may be made by the skilled mechanic; and such departures from what is herein described and claimed, not involving invention, I consider as within the scope and terms of my claims.

Having thus described my invention, I claim 1. A bolt adapted to draw or bind together two bodies, said bolt having a shank threaded at its lower part and provided throughout its length with a bore of polygonal shape, and a head furnished with a cavity diminishing in size from. the top to the bottom and corresponding in cross section to the shape of the bore of the shank, the sides of the cavity registering with those of said bore, substantially as set forth.

2. A bolt adapted to draw or bind together two bodies, said bolt having a shank threaded at its lower part andprovided throughout its length with a bore of polygonal shape, and a head furnished with a cavity diminishing in size from the top to the bottom and corresponding in cross section to the shape of the bore of the shank, the sides of the cavity registering with those of said bore, combined with a tapered cap having sides fitting the sides of the cavity of the head and furnished with a spring locking device, substantially as set forth. In testimony whereof I affix my signature in presence of two witnesses.




Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3044584 *May 27, 1959Jul 17, 1962Harris Foundry & Machine CoHollow cap screw assembly with displaceable plug
US3224316 *Sep 6, 1963Dec 21, 1965Detroit Testing Lab IncStress indicating mechanical fastening device
US4537543 *Jul 11, 1983Aug 27, 1985Scott Tommy LSecurity locking bolt
US5904081 *Jan 11, 1996May 18, 1999Santa Barbara Sensor TechnologiesFastener and tool combination for applying equivalent torque along fastener length
Cooperative ClassificationY10S411/919, F16B37/122