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Publication numberUS975285 A
Publication typeGrant
Publication dateNov 8, 1910
Filing dateOct 24, 1907
Priority dateOct 24, 1907
Publication numberUS 975285 A, US 975285A, US-A-975285, US975285 A, US975285A
InventorsPeter Lymburner Robertson
Original AssigneePeter Lymburner Robertson
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
US 975285 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)



Patentd Nov. 8; 1910.




tion of the same.

vThis invention relates to screws, the heads of which have axial driving recesses or cavi-- ties instead of transverse slots unched therein and the lnv'ention consists in a recess or cavity extending into the screw head,

the outer portion of the recess or cavity being prismatic and the inner portion thereof being pyramidal, the apex of the pyramid being in the axial line of the prism and of the screw. For full comprehension, however of my invention reference must be had to the accompanying drawings forming a part of this specification, in which similar reference characters indicate the same parts and wherein- Figure 1 is an enlarged axial sectional view of a screw embodying my invention; Fig. 2 is a top view of the same; Fig. 3 is a perspective view thereof at reduced scale;

' and Fig. 4 illustrates the screw driver point I prefer to employ in connection with my invention. 1

The body A of the screw and the'exterior I of its head B are of usual construction and in the head is punched my improved axial recess C. The recess is. square or prismatic in cross section throughout its depth fi the outer portions a of the four walls or sides beingflat and equal in area and the inner portions 1) being also equal in area and sharply converging in pyramidal form-to an axial point, the angle of convergence being approximately forty five degrees to the axial line of the screw. The outer edges of the recess are flattened or beveled as at e Specifi cation of Letters Patent. Application filed October 24, 1907. Serial No. 399,010.

and in the event of the screw being struck with a hammer in starting it, as is the practice, there will be no danger of the edge'being turned in to narrow the opening. The advantages of forming the cavity with walls presenting the outerprismatic or square portion and the inner pyramidal'portion converging at anangle of forty five (45) degrees and also square in cross section, are: first, that during thepunching of the cavity there is an equal distribution of metal in four directions laterally from an axial starting point instead-of a compression altogether in advance of the punch: secondly, in driving the screw a. combined effective turning power and centralizin 9f fect is possible as well as an equaldistribution of strain, the centralizing effect correcting any tendency of. the screw todeflectfrom. direct alinement with the driver and the vertical, horizontal and inclined corners, presented by the particular form of the walls, increasing the bearing surfaces for the driver.

What I claim is as follows:

A screw having a recess extending into its Patented Nov. 8, 1910..

matic to present four flat sides and the inner portion being pyramidal to also present four flat sides in continuation of and atangles of 45 degrees to the sides of the outer portion and the apex of the'pyramid being in the axial line of the prism and of the screw.

liamilton, Ontario, Canada, October 14th 190 7 PETER LYMBURNER ROBERTSON.

Referenced by
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US2522994 *Jul 19, 1946Sep 19, 1950Gen ElectricElectric circuit interrupter
US2556155 *Jul 13, 1946Jun 5, 1951Domnic V StellinSocket head screw
US2777353 *Oct 30, 1952Jan 15, 1957Robert W WillisScrew socket construction having tool guiding means formed therein
US2816473 *Jun 24, 1952Dec 17, 1957Katherine G LabbeeFastening device having a lock cavity for a screw driver
US4966599 *May 3, 1990Oct 30, 1990Pollock Richard AAnatomical precontoured plating, instruments and methods
US5020954 *Nov 29, 1989Jun 4, 1991Intools, LimitedScrew driving socket
US5199839 *Oct 9, 1991Apr 6, 1993Abbott-Interfast CorporationFastener screw having improved installation and self-locking characteristics
US6199455Mar 8, 1999Mar 13, 2001Jjct Enterprises, Inc.Driver, fastener and forming tool
US6575061Feb 5, 2001Jun 10, 2003John B. WagnerDriver, fastener and forming tool
US6948408 *Aug 17, 2001Sep 27, 2005Howard LeeFlat ended double cube shaped tipped, screwdriver system
US7727235 *Jun 29, 2005Jun 1, 2010Ethicon, Inc.Medical fixation devices with improved torsional drive head
US7730812Nov 7, 2007Jun 8, 2010Jone EdlandScrew head and tool for use therewith
US8734074 *Mar 8, 2013May 27, 2014Union Seimitsu Co., Ltd.Connecting member and connecting structure
US8739660Apr 19, 2010Jun 3, 2014Ttapdrive AsScrew head and tool for use therewith
US20070010820 *Jun 29, 2005Jan 11, 2007Contiliano Joseph HMedical fixation devices with improved torsional drive head
US20070036632 *Aug 12, 2005Feb 15, 2007Kwantex Research Inc.Screw having a head formed with an inner standard square recess part and an outer guiding recess part
US20130266397 *Mar 8, 2013Oct 10, 2013Union Seimitsu Co., Ltd.Connecting member and connecting structure
US20140132141 *Nov 13, 2013May 15, 2014Samsung Electronics Co., Ltd.Refrigerator and lower hinge module of the same
Cooperative ClassificationY10S411/919, F16B23/003