US2389129A

US2389129A - Universal screw driver

Info

Publication number: US2389129A
Application number: US501090A
Authority: US
Inventors: Joseph H Bishop
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-09-03
Filing date: 1943-09-03
Publication date: 1945-11-20
Anticipated expiration: 1962-11-20

Description

Nov. 20, 1945. V J. H. BISHOP 2,339,129

I v UNIVERSAL SCREW-DRIVER Filed Sept. s, 1945 4 OENEY:

Patented Nov. 20, 1945 2,389,129 UNIVERSAL SCREW DRIVER Joseph H. Bishop, Dayton, Ohio Application September 3, 1943, Serial No; 501,090

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757)- 1 Claim.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to screw driving tools and more particularly to that type of such tools characterized by the provision of a screw-engaging bit comprising a plurality of radially extending ribs, usually three or four in number, formed by the provision of either fluted or sharply angled recesses intermediate said ribs, which tool are adapted for screw-driving cooperation with screws provided with bit receiving recesses corresponding in shape to the particular form of bit of the type different configuration that neither is satisfactorily adapted for cooperation with the screwdriving tool specially designed for the other form of screw.

In practice, therefore, it is essential that, in any operation where both of the aforesaid two generally standardized forms .of'said screws are used, there be provided complete sets of screwdrivers of each type to fit the various sizes of each of the two standardized forms of recessed head screws, since the screwdriving tools designed especially for cooperation with one of said forms of screw are not interchangeable for use with the other form of screw.

The principal object of this invention, therefore, has been to provide a screwdriver bit which is adapted for use interchangeably with both of the aforesaid standardized forms of recessed head screws.

The various features of the invention will more clearly appear upon reference to the accompanying drawing, in which Figure 1 is an enlarged side elevation of the bit or working end of a screwdriver adapted for cooperation with one of the aforementioned standard forms of screw illustrated in Figures 2 and 3;

Figure 2 is a longitudinal sectional view of one,

of the standardized forms of screws generall in use, a portion thereof being broken away, the section being taken on line 2-2 of Figure 3;

' Figure 3 is a top plan view of the screw of Figure 2; I

Figure 4 is a side elevational view of the bit or working end of a screwdriving tool designed for use particularly with the form of recessed head screw illustrated in Figures 5 and 6 i Figure 5 is a longitudinal sectional view through a screw of another standardized form of screw generally in use, the section being taken on line 5-5 of Figure 6, a portion of the screw being broken away;

Figure 6 is a top plan view of the form of screw shown in Figure 5;

Figure 7 is a side elevational view of the bit or working end of a screwdriver embodying my invention.

Figure 8 is an end elevation of the bit or working end of the screwdriver of Figure 7.

The standard form of screwdriver shown in Figure 1 includes a cylindrical shank portion I and a working end or screw-engaging bit generally indicated by the numeral 2. The bit, in this form of a, standard screwdriver, comprises four ribs 3, formed by cutting recesses in the end of the shank I intermediate the ribs 3. These recesses are cut so that the respective ribs 3 are V provided with substantially fiat sides 4. The adjacent flat sides 4 of each pair of adjacent ribs 3 meet in a sharply defined line of juncture 5 at an angle of substantially ninety degrees, the lines of juncture 5 lying substantially midway between' the adjacent sides 4 of each pair of adjacent ribs 3. Th ribs 3 are conically tapered as indicated at 6 to a sharp point 1 at the extreme outer end of the bit 2.

The screw form illustrated in Figures 2 and 3 is provided with a recess generally indicated by the numeral 8 which is adapted to receive the bit or working end 2 of the screwdriver illustrated in Figure 1. The cruciform recess 8 corresponds substantially to the configuration of the bit end 2. In this connection it will be understood that the walls of the recess 8 converge inwardly to substantially a sharp point 9 at the base of the recess 8, the walls l0 of the recess 8 having a conical taper as indicated at H corresponding to the conical taper 6 of the ribs 3 and the walls ll) of said recess correspondin substantially with the configuration of the tapered portions of the ribs 3 and adapted to receive the latter. Likewise, it will be understood that the walls l2 conform to the configuration of the recesses formed by the flat sides 4 of the ribs 3 of the bit end of the screwdriver and said walls l2 extend into the recesses between the ribs 3 of the screwdriver when the bit end 2 of the latter enters the recess 8.

In the use of the screwdriver bit illustrated in Figure 1, in conjunction with the screw illustrated in Figures 2 and 3, the bit end 2 of the screwdriver is designed to fully enter. therecess 8 ofthe screw with the bit end point I engaging the base point 9 of the recess 8, the bit end 2 frictionally and wedgingly engaging in recess 8 in the fully cooperative relation of thescrewdriver and screw.

Now referring to the form of screw'and screwdriver designed for cooperation therewith as illustrated in Figures 4, 5 and 6, the'screwdriverof Figure 4 includes a shank portion [5 and a-bit end generally indicated by the numeral [6. The bit or working end l6 of the screwdriver of Figure 4 is likewise provided with alternate ribs and recesses, there bein four of each in the embodiment illustrated, the ribs being indicated by the. numeral H and the recesses being imiicatedby the numeral l8. The ribs H are not flat sided as are the ribs 3 of the form of screwdriver of Figure 1 but the recesses l8 are of'substantially concave or fluted configuration so that the extreme outer end IQ of the bit H5 is thickened and blunt and somewhat rounded, though bluntly pointed as at lac. The ribs H are conically tapered as indicated at 20 toward the blunt end 19 f the bit It, the cone angle beingsomewhat less than the cone angle of the tapered portion of the ribs 3 of the screwdriver of Figure 1,

The screw illustrated in Figures and '6 is provided with a cruciform recess, generally indicated by the numeral 22, which substantially conforms to the configuration of thebit end l6 of the screwdriver illustrated in Figure 4. The walls of the recess 22 converge toward the-outer confines 0f the blunt and somewhat rounded or concave base socket 23 at the lower extremity of the recess 22. The walls 24 of the recess 22 correspond in configuration with the conically tapered portions 20 of the ribs 11 of the screwdriver bit illustrated in Figure 4, the walls 24 of the recess 22 having the conical taper 25 corre-- sponding substantially with the conical taper 20 of the ribs I! of the screwdriver bit and the tapered portion 20 of the ribs I! being adapted to engage the walls 24 of the recess 22. The'walls 26 of the recess 22 correspond with the configuration of the recess 18 of the screwdriver 'bit illustrated in Figure 4, and the rounded or convex walls 28 of the recess 22 closely engage the recesses l8 when the driver bit of Figure 4- is co"- operatively associated with the screw illustrated in Figures 5 and 6.

It will be noted that while the

walls

24 and 26 of the recess 22 converge toward the outer'com fines of the base socket 23, they do not meet at the center of the base of the recess 22. On the other hand it is to be noted that'the t'apered'portions of the ribs 3 0f the screwdriver illustrated in Figure 1 converge to the point I, and likewise the walls of the recess 8 of the screw illustrated in Figures 2 and 3 converge to the base point 9. Also it may be noted that the outer extremity of the bit of Figure 4, in addition to being blunt, has ribs [1, the walls of which forming the recess 18 merge with one another in the curvature of the fluted recesses 18 so that the walls of adjacent ribs I! are not sharply defined angularly by a sharp line of demarcationintermed'iate the .same as is the case in connection with the fiat sided walls 4 of the ribs 3 of the screwdriver illustrated in Figure 1 which have the adjacent walls 4 sharply defined angularly with respect to each other meeting in a sharp line of demarcation 5 as illustrated in Figure 1. Since the recess 8 of the screw illustrated in Figures 2 and 3 likewise has sharply defined walls In and I2 converging at the sharp'base point 9 of the recess 8, it will be apparent that the bit l6 of the screwdriver illustrated in Figure 4 is not adapted to enter the recess 8 of the screw illustrated in Figures 2 and 3.

It willalso be apparent that the bit 2 of the screwdriver illustrated in Figure 1 will not fully enter the recess 22 of the screw illustrated in Figures 5 and 6 for proper cooperation therewith because when the bit 2 is inserted in the recess 22, the pointed extremity of the bit will engage the lower rounded base socket 23 of the recess 22 before full entrance of the ribs 3 into the recess 22 and cause the tapered edges of the ribs 3 to stand away from the walls 24 of the recess 22 so that the proper cooperative relation between the bit of Figure 1 and the screw of Figure 5 cannot become established. For the foregoing reasons it will be apparent that the standard forms of screwdrivers illustrated in Figures 1 and 4 (lesigned particularly for cooperation with the screws illustrated in Figures 2 and 3 and Figures 5 and 6, respectively, are not interchangeable for use of either screwdriver of Figures 1 and 4 with the other standard form of screw.

Since a large number of screws of both of the types illustrated in Figures 2, 3, 5 and 6 is required foruse in various structures employed for military purposes and particularly military airplanes, the Government has heretofore found it necessary to provide complete sets of screwdrivers of both of the forms illustrated in Figures 1 and 4 for use with the various sizes of the two forms of screws illustrated in Figures 2, 3, 5 and 6. Obviously, it would be very advantageous under the circumstances to supply a single screwdriver bit which is interchangeably adaptable for use with both types of screws, and the provision of such a universal screwdriver bit has been the object and the accomplishment of this invention, resulting. in a tremendous saving of critical material and other economies from the standpoint of the weight saving factor in respect to the weight of tools requiredto be transported for service of military airplanes and from the standpoint of economy in actual service time in eliminating delays which would otherwise ensue were the particular required driver bit not immediately available.

.Now referring to Figures '7 and 8, there is illustrated in these figures the universal screwdriver bit of theinvention which is adapted for screwdriving cooperation with both of the standard formso'f screws illustrated in Figures 2, 3, 5 and 6.

The screwdriver of Figure 7 comprises a cylindrical shank 38' having a screw recess engaging bit 3| at one end thereof. The bit. or working end 3| of the screwdriver comprises four ribs 32 extending radially from the central longitudinal axis of the shank 30 which is the axis of rotation of the shank when the screwdriver is bein used for driving a screw. This axis is hereinafter called the driver axis. As illustrated in Figures 7 and 8, the ribs 32 are equally spaced angularly around the driver axis. The bit 3| is Provided with sharply angled recesses intermediate the ribs 32, said recesses being formed by the substantially flat sides 33 of said ribs, the adjacent sides.33 of. each pair of adjacent ribs meeting in a sharply defined line of juncture 34 at the angle of substantially ninety degrees. The ribs 32 have a conical taper, as indicated at 35, the axis of the conical taper being common to the driver axis, and the ribs taper inwardly toward the outer extremity of the bit 3|. While the tapered edges 35 of the ribs 32 converge toward the driver axis, said tapered edges 35 do not meet, as contrasted with the fact that the tapered edges 6 of the ribs 3 meet at the point I in the case of the driver bit illustrated in Figure 1. The tapered edges 35 of the driver bit illustrated in Figure 7 are foreshortened to provide a relatively wide and preferably flat bit end 36 constituting the outer edges of the ribs 32, the extreme outer surfaces of which preferably are in substantially a common plane perpendicular to the driver axis. As best illustrated in Figure 8 the bit end 36 is in the form of a clearly defined right-angle cross and the adjacent sides of each pair of adjacent ribs meet in substantially right-angle relationship at the sharply defined points 31 at the outermost extremity of the bit end 36. The points 31 are formed by the inward convergence of adjacent sides 33 meeting in sharply defined lines of juncture 34 which extend to the outermost extremity 36 of the bit 3|.

Upon reference to Figure 8 it will be noted that the sides of each rib 32, at the extreme outer end 36 of the bit 3|,where they define the cruciform bit end 36, are substantially parallel. It will also be noted from Figure 8 that the adjacent sides of adjacent ribs 32, at the outer extremity of the bit 3| where they define the cruciform bit end 36, are substantially perpendicular to one another where they meet at the sharply defined points 31.

Preferably the angle of the conical taper 35 of the driver illustrated in Figures '7 and 8 may be intermediate the angles of the

conical tapers

6 and 20 of the drivers illustrated in Figures 1 and 4, but the provision of such an intermediate angle for the conical taper 35 is not absolutely essential to the operability of the driver illustrated in Figure 7 for the purposes of interchangeable cooperation with the screws illustrated in Figures 2, 3, and 6. It will be apparent in any event that if the conical taper 35 substantially corresponds with the conical taper of either of the drivers illustrated in Figures 1 or 4, the driver illustrated in Figure 7 will be interchangeably cooperable satisfactorily with the screws illustrated in Figures 2, 3, 5 and 6.

When the universal screwdriver illustrated in 1 Figure 7 is used in cooperation with the screw illustrated in Figures 2 and 3 the bit end 36 will, of course, not extend to the base point 9 of the recess 8 of said screw and yet, because of the sharply angled relationship of the meeting lines of adjacent walls of adjacent ribs at the end36 of the bit 3|, the latter will properly enter the recess 8 and the conical edges of said ribs 32 will sufilciently engage the walls Ill of said recess 8 to establish proper driving cooperation of the bit and screw. Likewise, since the tapered edges 35 of the ribs 32 of the driver illustrated in Figure 7 are foreshortened to terminate in the blunt end 36, the ribs 32 will properly enter the recess 22 of the screw illustrated in Figures 5 and 6 and sufiiciently engage the walls 24 of said recess 22 to establish proper driving cooperation between the bit and screw.

I am aware of the United States patents of West, 2,216,381; Thompson, 1,908,081; Werne, 2,235,781; Frearson, 145,411 and 308,246; and Phillips, 2,046,837; 2,046,838; and 2,046,840; and I make no claim to the subject matter of these patents.

What I claim as new and desired to secure by Letters Patent is:

A screw driver of the class described comprising a bit, the eifective screw engaging portion of said bit comprising a plurality of ribs extending radially from the driver axis and terminating in a flat transverse end edge, said ribs having fiat sides, the sides of each rib converging toward said end edge, the adjacent sides of the adjacent ribs meeting angularly in sharply defined lines of juncture extending to the end edges of said ribs, the side edges of said ribs having a conical taper, the tapered side edges of said ribs converging toward the end edges of said ribs.

JOSEPH H. BISHOP.