US393421A - Screw-driver - Google Patents

Description

UNITED STATES PATENT rrrcn SCREW- DRIVER.

SPECIFICATION forming part of Letters Patent No. 393,421, dated November 27, 1888.

Application filed April 28, 1888.

.To (tZZ whom, it may concern:

Be it known that I, FELIX CHANTRELL, a citizen of the United States, residing at Heading, in the county of Berks and State of Pennsylvania, have invented certain new and useful Improvements in Screw-Drivers; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and figures of reference marked thereon, which form a part of this specification.

This invention relates particularly to hand tools-such as screw-drivers in which it is desired to rotate the handle with or without the shaft.

The object is to accomplish this in a more satisfactory and efficient manner, and at the same time more economically than has heretofore been done. The means now in use to secure the desired results in tools of the kind referred to involve the use of a serrated or toothed surface arranged at right angles to the axial line of the shaft, the separate parts being revolved together when the serrations or teeth on one surface are brought into engagement with corresponding serrations or teeth, a pivoted dog, or equivalent, device on the other. This construction becomes more or less complicated and expensive, and when the teeth or equivalents are sufiiciently strong and present enough surface to prevent excessive wear a considerable longitudinal movement is required to throw the parts into or out of engagement, and there is also an objectionable amount of circular lost motion before the teeth on one surface coincide with the correspond ing recesses on the other.

In my device I discard the serrations or teeth above described and secure the requisite engagement between the revolving parts on the outer surface of a tapered shank end, a preferred construction on this principle being illustrated in Figures 1 and 2 of the drawings, Fig. 1 being an elevation, partly in section, of a complete screw-driver, the handle and shaft being represented out of engagement, Fig. 2 giving an isometrical view of the handlebushing detached. Fig. 4 is a cross-section of the handle-bushing.

Serial X0. 272,124. (NouiodeL) A represents a wooden handle, the external appearance of which does not differ from those ordinarily used for screw-drivers and similar tools. It is, however, bored centrally through its entire length to two different diameters, the larger part of the hole Leing in the heavy pant of the handle, while the smaller bore extends through its reduced part, leaving an interior shoulder or offset, A, where the two sizes conneet.

The shaft B is a round piece of rolled steel tapered and shaped at one end to suit ascrewslot.. Its diameter is such as to loosely fit the small bore of the handle, into which the plain shank end of the shaft is inserted until itpro jects beyond the heavy end of the handle. The cap-piece D, which is represented in the form of a frustum of a pyramid, the base or a parallel section of which at any point of its height is a many-sided polygon without re entering angles, and which is also formed with a hole suited to the size of the shaft, is then forced on or otherwise securely fastened to the shank of the shaft, which is subsequently allowed to drop until the base of the rap rests upon the offset A in the handle.

The handle-bushing O (as also the cap-piece D above described) may be cast of malleable iron or other metal, the outside longitudinal corrugations, O, or their equivalent, as well as the interior shape, with flat faces C corresponding with the outside surface of the cap D, being formed complete in the foundry, ex-

cept that a properly-shaped tool may be driven into it to remove sand and burrs and so insure its fit on the cap. The bushing is sufficiently long to give room for a spiral spring, E, between the end face of the cap (when the latter is inclosed by the bushing) and the shoulder (J in the top part of the latter, which forms a seat for the spring.

The above-described bushing, which is of such an outside diameter as will tightly fit the large bore of the handle, and is also slightly tapered or rounded at the bottom to permit of its being readily entered, with the spring E inolosed, is pressed into the handle, the surplus wood being compressed and forced into the grooves C until the cap D is inelosed by the bushing as far as possible without engag ing with it when the base of the cap is pressed against the offset A by the spring. The plug 1 F is then glued or otherwise fastened in the handle above the bushing, which latter is thus effectually prevented from pushing out or turning in it. This method of securing a sleeve or equivalent in the heart of the handle has been previously described and claimed in my pending application, Serial No. 267,66l, and the means herein set forth for engaging the handle and the shaft is an improvement on my previous application, Serial No. 266,331.

The method of operating a tool constructed as above described is obvious. XVhen applied to a screw-driver, as shown, the point being placed in the screw-slot, a moderate end pressure on the handle compresses the spring and permits the shank-cap to seat itself in the sleeve. WVhen the handle is then rotated, the shaft and screw rotate with it, the tlat sides and corners of the cap and sleeve. respectively, compelling them to turn together. On removing the longitudinal pressure the spring moves the handle just sufiicieutly to allow it to be returned without engaging the shaft, which remains stationary until the handle is again rotated in the same direction. The hand which grasps it need not be shifted.

The advantages of this general method of construction consist, as previously noted, not only in increased economy of manufacture, but also in more satisfactory working, consequent on the large surface of the shank which is thrown into engagement with the handle by a slight movement as compared with the use of the usual end serrations or teeth.

I do not wish to limit myself to the construction shown, as it is obvious that various modifications may be readily devised. Fig. 3 represents one equivalent form in which the cap-piece is dispensed with and the end of the shaft itself shaped to suit the sleeve, the lat ter being of smaller diameter than that shown in Fig. 1. The method here indicated of preventing the withdrawal of the shaft by means of a projecting stem, G, extending through the bushing and having a head, G, formed on the end of it, is similar to that described in my pending application, Serial No. 266,331.

What I desire to secure are the following claims:

1. In a screw-d river or similar tool, a drivershaft having a tapered shank end of regular polygonal crosssection, in combination with a rotatable handle provided with a fixed bushing having its interior shaped to correspond with said shank end, and a spring. all adapted to operate substantially as set forth.

2. The driver-shaft having a cap'piece of regular po ygonal cross-section secured to its shank end, in combination with a rotatable handle provided with a correspondinglyformed bushing adapted to engage said cappiece, and a spring, all adapted to operate substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

FELIX CHANTRELL.

Witnesses:

GARRETT B. STEVENS, F. PIERCE HUMMEL.

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