Patented May 23, 1933
United States Patent Office
Peter L. Robertson, of Milton, Ontario, Canada
Slotted Socket Screw
Application filed October 18, 1930. Serial No. 489,607.
The principal objects of this invention are to provide
a screw which will be readily driven either by the ordinary
flat blade screw driver or by the tapered squared end
screw driver used for socket screws.
A still further object is to provide a screw which
may be readily adjusted by either type of screw driver,
thus obviating the inconvenience and annoyance due to
either form of screw driver not being available.
A still further object is to provide a screw, the head
of which will very securely grip the end of the socket
screw driver and which will also facilitate the entrance
of the screw driver into operating engagement.
A further and important object is to enable the production
of a combined slot and socket screw with the minimum
displacement or removal of material, effecting a reduction
of wear and strain on the forming tools and a resultant
reduction in cost of the finished article.
The principal feature of the invention consists in
the novel construction of a screw head with a rectangular
socket having slightly tapering sides and chamfered
edges leading thereto, together with a tapered end to
receive the pyramidal end of the screw driver and which
is diagonally intersected by a deep slot cut across
In the accompanying drawing, Figure 1 is a plan view
of my improved form of screw head as applied to a countersunk
Figure 2 is a vertical mid-sectional view of the screw
shown in Figure 1.
Figure 3 is a plan view of a modified form in the form
of a round head screw.
In the invention herein shown, the screw head 1 is
formed with a central squared socket which is punched
into the material of the screw and has the very slightly
tapering side walls 2 which are formed with the chamfered
edge 3 at the outer side and lead to the pyramidal converging
A slot 5 is cut transversely of the head 1, preferably
across the diameter of the squared socket.
The provision of this slot does not in any manner interfere
with the action of the tapered end and pyramidal pointed
screw driver which is directed into the recess by the
chamfered edges 3 and securely grips the tapered surfaces
4, the pyramidal point guiding it into place.
In the form of the invention shown in Figure 3 a round-headed
screw is shown with the transverse slot 6 extending
across the diagonals of the tapered rectangular orifice
7, into which the pyramidal-shaped end of the socket
screw driver is inserted.
The transverse slot does not in any manner detract
from the use of the rectangular socket but it does enable
the use of the screw or the adjustment thereof where
a socket screw driver is not available and a flat bladed
screw driver may be used.