US2359898A

US2359898A - Fastener element

Info

Publication number: US2359898A
Application number: US461007A
Authority: US
Inventors: Eugene E Clark
Original assignee: AMERICAN SCREW CO
Current assignee: AMERICAN SCREW CO
Priority date: 1942-10-06
Filing date: 1942-10-06
Publication date: 1944-10-10
Anticipated expiration: 1961-10-10
Also published as: DE844997C; GB567469A

Description

061 10, 1944. CLARK 2,359,898

FAsTENER ELEMENT Filed Oct. 6, 1942 Patented Qct. 10, 1944 FASTENER ELElVIEN T Eugene E. Clark, Providence, R. I., assignor to American Screw Company, Providence, R. I., a corporation of Rhode Island Application October 6, 1942, Serial. No. 461,007

Claims.

This invention relates to screws and allied fasteners of the rotatable type and more particularly to a novel form of screw head recess for engagement by various forms of screwdrivers and substitutes .therefor.

It is a general object of the present invention to provide a novel screw or fastener element provided with a recess for driving the same and adapted to accommodate several well known forms of screw-drivers.

More particularly the invention comprises a combination head recess for fastening elements adapted to accommodate the conventional Phillips type of screw-driver, a conventional screwdriver or a small coin.

The most common form of screw for wood and machine use has heretofore been equipped with a transverse kerf intersecting the periphery of the head and adapted to receive a screw-driver having a thin fiat blade. Deficiencies in the cooperating qualities of this kerf and the blade which resulted in slippage, burring, and other troubles led to the development of a number of so-called recesses for screw heads which were in most cases entirely confined within the peiiphery of the head to prevent marring the material into which the screws were introduced by exposed portions of the driver. recess that has become so popular that it is beginning to entirely supplant the conventional kerf in screws for a great many purposes and industries and which is available from a number of manufacturers is that known by the name Phillips. in Patent 2,046,839, granted to H. P. Phillips et al., July 7, 1936. It includes a deep central recess and four radiating grooves adapted to cooperate with wings on a special screw-driver.

Because of the many desirable features of the Phillips recess it is specified for a great number of purposes in various industries, but in some cases there has been one drawback to its more universal use. It requires a special screw-driver which on some occasions may not readiy be available, particularly in the field where repairs or adjustments must often times be made. It is the purpose of the present invention to so modify the Phillips recess as to retain all of i s well known advantages and yet to perm t the use, where necessary, of a conventional flat bladed screw-driver or even a small coin which may at times be more ieadily available than any form of screw-driver.

Broadly the modification consists in superimposing over one pair of the radio grooves of the Phillips recess, of a segmental, diametrically d sposed, parallel-sided kerf or groove terminating short of the periphery of the screw head and Such a recess is shown and described One form of being shallower than the central portion of the Phillips recess and the innermost portions of the Phillips grooves over which it is applied. This groove is sufficiently wider than the Phillips grooves to eliminate their upper configuration and to present a slot for a conventional screwdriver of considerable thickness whereby the groove may also accommodate a small coin.

For a better understanding of the invention reference should be had to the following specification and the accompanying drawing wherein is disclosed a single exemplary embodiment of the invention with the understanding that such changes may be made therein as fall within the scope of the appended claims without departing from the spirit of the invention.

In said drawing:

Figure 1 is a plan view of the head of a screw or other fastening device equipped with the combination recess of the present invention;

Figure 2 is a longitudinal central section taken on line 2-2 of Figure 1;

Figure 3 is a view similar to Figure 2 but taken at right angles thereto as on line 3-3 of Figure l; and

Figure 4 is a partial section through a cowl fastener of the type used on present day aeroplanes showing the rotatable element thereof equipped with the combination recess of the pzesent invention.

The invention has been shown for convenience, as applied to the so-called fiat, headed type of screw but obviously it is as well adapted for the several other well-known types of heads and it is not the intention to restrict the claims to any specified head shape.

Referring row to the drawing, the screw will be seen to comprise the shank I0 and the head ll conta ning the screw-driver engaging recess generally indicated by the reference character 12. Basically this is the Phillips recess as illustrated in the patent above identified. The central portion I4 of this recess is seen to reach down into the shank of the screw and to have a blunt bottom which is generally concave transversely to the axis of the shank and is of sufficient area and contour to complement the lowermost end of the Phillips screw-driver. The walls of this recess are preferably eight in number and are tapered or splayed outwardly as shown at l5. Initially there are four similar grooves I6 radiating in cruciform disposition from the central recess. As seen in Figure 3 the bottoms H of these grooves slope upwardly from the periphery of the concave bottom and increase in width as seen in Figures 1 and 2 from the bottom toward the surface of the screw head. Each of these grooves is defined by a pair of triangular side walls It which converge downwardly toward each other and unite with the substantially flat bottom I! just mentioned. These walls I8 merge along lines IS with the walls l of the central recess.

To provide accommodation for a coin or a conventional screw-driver the kerf or slot 20 is provided which as shown in Figure 2 is generally of segmental shape and having the curved bottom wall 2| which is centrally interrupted because it is of less depth than the central portion of the main recess. At each end this wall intersects the surface of the head in a straight line 22 some distance inside of the head periphery. The side walls of the recess as shown at 23 and 24 are substantially parallel to each other and to the axis of the shank. The total length of the slot 20 is considerably greater than the combined lengths of a pair of opposed grooves of the Phillips recess so that a relatively large size conventional screwdriver may be accommodated.

It will be seen that in general the slot 20 is coextensive with one pair of the Phillips grooves which are thereby materially shortened as seen at 26 in Figures 1 and 2 because their inclined bottom walls I! intersect with the-curved bottom 2| of the shallower kerf. Preferably this kerf bottom is curved longitudinally but flat transversely as seen at 25 in Figure 3. There is, however, a sufficient radial length of each of the reduced Phillips grooves remaining to offer a substantial driving surface for the cooperating wings of a Phillips screw-driver.

It will be seen that the combination recess above defined is highly effective for use with the standard Phillips screw-driver, with a relatively large conventional screw-driver, or with a small coin. The possibility of using a coin is of particular advantage when the groove is used in the head of the rotatable fastener element 30 of an aeroplane cowl fastener such as illustrated in Figure 4, the purpose of which is to secure an outer sheet or metalplate 32 rigidly against an inner plate 33 and yet to permit the rapid removal of the same for servicing the motor or other parts. The rotatable element 31 includes a transverse pin 34 or like extensions adapted to cooperate with cam surfaces 35, upon being rotated, to draw the two sheets tightly together. The torque necessary for rotating the element of this type of fastener is considerably less than that required for driving a screw in hard wood so that a readily available coin or small washer, in the absence of a more conventional tool, will serve to release the fastener element and permit separation of the cowl from substantial fixed parts of the plane. The type of cowl fastener illustrated is only exemplary but all known forms use a rotatable headed fastening element to which the present combination recess is adaptable. Since so many aeroplane claimed as new and desired to be secured by Letters Patent is:

1. A fastener element having a head and shank, a recess in the head thereof adapted to accommodate a coin, a Phillips or a conventional screw-driver, said recess being provided with a concave bottom extending transversely of the axis of the shank, and having tapering convex side walls diverging upwardly from the bottom to the top of the recess, four tool receiving grooves extending radially from the recess, one oppositely disposed pair of said grooves having side walls which merge throughout their length with the .convex side walls of the recess and another oppositely disposed pair forming a parallel sided segmental kerf sized to fit a coin but of less length than the diameter of the head.

2. A fastening element having a head and shank, a recess in the head thereof adapted to accommodate a coin, a Phillips" or a conventional screw-driver, said recess comprising a central depression extending transversely of the axis of the shank and into the shank and two pairs of opposing grooves each extending radially from the depression, each of the grooves of one pair tapering in width from the depression outwardly, having fiat tapered side walls and a flat tapered bottom wall, the other pair of grooves each having flat, parallel side walls and a bottom wall curved in the direction of its length but of unlform width.

motor parts are secured with screws equipped may be formed by a cutting or sawing operation.

,Having thus described the invention, what is 3. In a fastening element having a head and a shank, a recess comprising a centrally spaced main slot terminating short of the periphery of the head, the side walls of the said slot being parallel to each other and to the shank axis, the intersections of the said walls and the bottom of the slot being arcuate, the arcuate bottom wall intersecting the top of the head at the ends of the slot, a central well in said head having a concave bottom transverse to said axis and below the bottom of said slot, two pairs of tool receiving grooves extending radially from the well and having side walls converging from top to bottom, one pair of said grooves being coextensive with said slot and deeper than the same.

4. In a fastening element having a substantially flat head and a shank, a diametrically disposed slot in the head sized to accommodate a coin and terminating short of the periphery of the head, the bottom wall of the slot being arcuate, the arcuate bottom wall intersecting the top of the head at the ends of the slot, a central well in said head having a concave bottom transverse to said axis and below the bottom of said slot, two pairs of tool receiving grooves extending radially from the well and having side walls converging from top to bottom, one pair of said grooves being coextensive with said slot and deeper than the same.

5. A fastener element comprising a shank and a head, said head having a central recess bounded by tapering side walls diverging from the bottom to the top thereof, cruciform tool blade receiving grooves extending radially from and communieating at their inner extremities with said recess, said grooves-being defined by oppositely disposed side walls which merge with the side walls of said recess and diverge upwardly, at least two of the oppositely disposed radial grooves having relatively shallow radial extensions to accommodate a relatively wide turning blade.

EUGENE E. CLARK.