US1782981A - Screw driver - Google Patents

Description

NOV' 25, 1930. J. A. ANDERsoN 15782581'- SCREW DRIVER Filed Dec. 24, 1929 3 Patent ed `Nov. 2 5, 1930 CRA' , 1 UNITED; STATES' CORPORATION OF CONNECTICUT PATENT*OFFICE? JOHN A. AixTsDERsoiv,` or BRIDG-Eron'r, oonnncriounnssieivon roman imrnenronr i HARDWARE MANUFAGTURING CORPORATION,zorrnrnenrom, oonnnofrmnr; 'A i sonnw DRivER p y I This invention relates to sorew drivers,

and has for an object to improve upon the vide a construction which can be used to effectively operate screws in which the kerf has been so deformed as to be incapable of operation by the ordinary plain screw driver.

With the foregoingand other objects in' view, the invention consists in certain novel features of constructlon and arrangement of parts as will bemore fully disclosedin `coni sharp to bite into the side walls ofrthe kerf 17 of the screwV head 18 upon turning4 '14. 11 and 12 there is provided a transverse rib nection With the accompanying drawing.

In this Vdrawing` Ihg. 1 is a side .elevatlon ofa screw driver shank constructed according to the preferred embodiment'of the invention;

Fig. 2 is a fragmentary 'edge elevation of` the same on an enlarged scale showing the screw driver in the kerf of a screw.

Fig. 3 Vis an enlarged section substantially on line 34-8of Fig.'1.

Fignlis an enlarged end view taken substantially as indicated by' line 4-4 ofFig. 1`,and

Fig. 5 is an enlarged fragm'entary longitudinal section 'substantially on line 5-5 of Fig-1.`

The shank of the screw driver, as is usual,'is provided vwith two opposite side faces 11 'and 12 and two edge 'faces 13 and On either one or both of the side faces '15 which extends transversely of Vthe bit 'closely adjacent the free end 16 of the bit.

The free edge of this rib is sufliciently movement of the screw driver in the `kerf, and the biting action very effectively resists slipping of the bit from the kerf in a direct tion longitudinally of the shank. The side wall of the kerf during the turning movement oftheibit to 3` prevent slipping of` the blt transversely in the kerf or to rresistj both but Ihave shown in theaccompanyingdrawmg two series of'inclined `ribs 19` and .20, these `ribs being preferably arrangedlto extend` obliquely` from the longitudinal center line 21 to theop'poste" edge faces 13 ``and 14 and inclined toward the free end 16.-` The ,transversefand longitudinal slipping. Vari lous means may be provided for doing this,V

angle of 'inclination may vary depending'onv whether it is desired to emphasize resistance to lateral slipping in the kerf or resistance to Vlontgiltudinal i slipping. s Withthe ribs infrom the kerf and thus.` more eflectively assists in holding :it thekerfQThis construction`` and arrangement`` :using the transverse rib `E incombination with theother holding means 11squlte an improvement over la conw struction inxwhichthe ribs'19rand only areprovided andv run'o'utzthe endjlG. Particularlyis this truein a casewhere the bit` is used in a kerf which is relatively, shallow orzhasrbeenbadlyiworn or deformed. In

such icases, the transverse' frib 151 materially' assists in gripping* .the kerf for operating .a

screw.- `Alsothe ribs-l`` strengthenthe freef end ofth'e bit whichis the thinnest poltion w of' the bit and 1 is` also.` the`l portion` which' is I `more'apttolbeibrokenoriinjilred. Theribs I 15` makel this end portionmuch stronger. r

The ribs .and holdingmeans may be fo'rmed a ;in anyimanner` desired as for example, raising r them 4on the surface or by providing grooves or depressions in the surface.` It is alsonot necessary -thatthe edges of the ribs be particularly sharp as all that is necessary is that they be sufiiciently sharp to bite into the side walls of the lrerf sufficiently to holdthe bit against slipping.` It is also not necessary that the. auxiliary holding means above the transversewribsl be as shown on the drawing as other shapes and arrangements ofsharp edged means may be provided to bite into the side walls of the kerf in the turning operation. i

In use the bit is inserted in the kerf in the same way as is any screw driver, and this screw driver does not require a special form of screw or kerf, but can be used with any standard or other screw having a kerf. As a matter of fact, it will grip into a kerf which has been greatly worn or deformed to such an extent as to be practically impossible of use for operation of the screw by the ordinary m plain screw driver. The transverse rib 15 is particularly useful in certain kinds of kerf as it very effectively bites into the side walls thereof closely adjacent the very bottom of the kerf. rl`he width of the kerf is practically 15 innnaterial as this device is effective in both relatively wide and nari'ow kerfs.

Having thus set forth the nature of my invention, what I claim is:

1. A screw driver comprising a shank pro- 2,9 vided with a screw driving bit having two opposite side faces, one of said faces being provided with a rib extending transversely of said face closely adjacent the free end of the bit and extending laterally outward, said face also having ribs extending from a central longitudinal line of the shank at an oblique angle to the shank toward said first rib, said obliquerribs and the transverse rib blending into each other so that they form So continuations of each other and are adapted to engage a wall of a screw head kerf to resist both longitudinal and transverse slipping of the bit in the kerf during the turning moveinent of the screw driver.

25 2. A screw driver comprising a shank provided with a screw driving bitihaving two opposite side faces and two edge faces joining the side faces, each of the side faces having a rib extending transversely of said face ,io closely adjacent the free end of the bit, each of the side faces also having ribs extending from a central longitudinalline of the shank and at an oblique angle to the shank toward said edge faces, the oblique ribs nearer the :+1 end of the bit and the transverse ribs blending into each other to form continuous ribs adapted to engage opposite walls of a screw head kerf to resist both longitudinal and transverse slipping of the bit in the kerf dur- 511 ing the turning movement of the screw driver.

In testimony whereof I affix my signature.

JOHN A. AND'ERsoN.

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