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Патент USA US2106278

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Jan. 25, 1938.
- ‘Filed Feb. 29, 1936
Patented Jan. 25,v 1938.
Martin n. Redmer, Chicago, m.
‘ Application February 29, 1936, Serial No. 66,369
3 Claims.
(01. 151-32)
My invention relates to screws.
More particularly, my invention relates to an
improved type of head fora screw whereby the
screw may be threaded more readily into place
5‘ without destroying the head by failure of the
type which can be readily placed in the recess in
the screw head and, by slight tapping, caused’
to wedge itself against the walls of the recess
and the part receiving the screw-éthe construc
tion of the locking device-permitting, not only or
of simple use and low cost of manufacture, but‘
wrench or screw driver to align properly, or to be
also of ready removal in case it is desired to with
?tted in the head.
As manufactured today, the type of screw ’ draw the screw.
known as the socket screw, ‘which is usually
Further objects of my invention will be appar
ent from the/following detailed description taken 1 v
in connection with the accompanying drawing.
H) countersunk
in‘ the parts into which it is
threaded, is generally provided with an octagonal
recess in its head 'toreceive a key wrench. The
octagonal shape of the recess provides surfaces
between the recess and the key wrench which
do not oppose the turning effort as‘e?iciently
as a surface extending substantially radially out-.
wardly so as to be practically transverse to the
turning effort.
Consequently, a key wrench must
?t the recess with considerable accuracy to pre- '
vent destruction of ‘the recess by the sharp cor
ners of the wrench. Moreover, an octagonal
recess requires~ removal of material from that
part of the head which considerably weakens the
head. As the screw is driven into position and
I; SI the head is coiintersunk, an octagonal recess pro
vides no means for locking the screw in place
to prevent it from accidentally becoming loose.
An object of my invention is to provide, there
fore, an improved type of recess in the- head of
30 a screw,‘ which recess is preferably in the form
of opposed sectors open at the edges of the head.
the present invention;
may be used;
Fig. 4 is a view of the end of the key wrench
that ?ts into the recess in the head of the screw;
Fig; 5 is an edge view of a key or locking device
adapted to be inserted in the recess of the screw
Fig. 6 is a plan view of this key
or locking de- '
Fig._ 7 is a sectional view illustrating the screw
driven into position and the head of the screw
countersunk so ‘as to show the manner in which
this key or locking device prevents the screw from
vibrating or otherwise working loose; and
Fig. 8 is a perspective view illustrating the
this key or locking device when it is desired to
scribed, which does not weaken the construction
remove this screw.
gaging surfaces between the head and the key
wrench that are in the most e?icient position
to transmit the turning force. Accordingly, the
screw may be threaded into position and tight
40 ened with minimum turning effort and without
the danger of destroying the head.
A further object of my invention is to provide
an improved type of recess in the head of a
screw thatermay receive a key or like locking
45 member after the screw is tightly driven into
position, which will prevent the screw from vi
brating or otherwise working loose.
According to the present invention I further
contemplate providing a novel key or locking de
vice that may be inserted into a recess of a screw
Fig. 2 is a planlview of the screw head;
Fig. 3 illustrates the type of key wrench that
A‘further object of my invention is to provide
a recess in the head of a screw of the kind de
35 of the head, and which further provides for en
In the drawing:
Figure 1. is a perspective view of a screw hav
ing a recess in its head of the type embodying _
manner in which a- tool may be used to remove
Referring now to the drawing, Fig. 1 illustrates 35
a screw having a threaded shank ! and a head ,
2. Opposed sector-like recesses are provided in I
the upper part of screw head 2.
These opposed
sector recesses are designated 3 and 4 and are
joined at the center of the head, as indicated at
5, in a somewhat restricted manner due to this
sector formation, the center portion 5 ‘being of ' '
such width as to permit insertion of a key
wrench of corresponding shape. It is noted that
sector recesses 3 and 4 extend outwardly to and
are open at the edges 6 and 1 respectively of
screw head 2. Becesses .3 and 4 provide walls
8 and 9 acting as engaging surfaces for the key
wrench and being substantially radial so as to
be somewhat transverse to the turning effort.
In the manufacture of the screw head 2, walls
head and locked thereinklin a manner to bind
against the part into which the screw is counter A 8 and 9 are cut at anvangle to require but two
sunk and thereby lock the screw in position.
'~"_ milling operations in the formation of recesses
In this connection, it is a still further object of 3 and-4. Although I_ do not necessarily Wish to
, the invention to provide a locking device of this be limited to an exact angle of cut for walls 8 .> '
and 9, I have found that by setting the milling
cutters at 15° with respect to the horizontal, only
two cutting operations are required to form these
' recesses 3 and 4.
After the ?rst cutting opera
tion,‘ the milling cutter may be indexed so that
an opposite cut at 15° may be performed to form
the opposite walls. No material. is then left in
the center of the recesses at the edges v6 and 1.
One of the advantages, therefore, of cutting re
10 cesses 3 and 4 outwardly to the edges 6 and ‘I
resides in the simplicity of operation and inex
pensive cost of production. Walls 8 and 9 re
main in an angular position sii?icient to be some
what transverse to the turning movement, and
therefore, in the most efficient position when the
key wrench is inserted’ to operate to thread the
screw into locking position or to remove the same
from locked position. Screws of this type are
quite frequently used as‘ keys to lock rotating
20 parts together, such as is shown in Fig. 7.- This
requires that the screw be driven into position
as tightly as possible so that there is no op
portunity for slippage between the rotating parts.
Moreover, it is essential that the screw remain
locked to keep these operating parts keyed to
gether. The formation of recesses 3 and 4 ad
vantageously permit the use of a key-‘lock shown
in Figs. 5 and 6.
This key-lock, designated l2,
‘ is of substantially the same cross section as re
cesses 3 and 4, but may be slightly curved so
that when key-lock I2 is inserted in these re
cesses it may be tapped slightly to cause dis
tortion and a wedging action with the walls 8
and 9 and the side wall of the part in which
head 2 is countersunk. For example-in Fig."7 I
have illustrated, say, a driving shaft i3 and a
driven shaft l4.
The screw is used as a key to
lock parts I3 and I4 in driven relation.
2 is countersunk as is usual in these cases.
40 Countersunk screws of this type may have an
enlarged head 2, as shown in Fig. 1 ‘of the draw
ing. It may also have a head of the same diam
eter as shank I, as is well understood and com
in position and effectively to prevent'vibration.
loosening or permitting the screw to work loose.
The arcuate edges P5 of this key-lock effectively
grip the wall l6 when this key-lock is inserted
in the recesses. Furthermore, key-lock I2 is Cl
permanent’ in its action and will remain in the
recesses of head 2 until forcibly removed by
means of a punch I8 or other sharp instrument.
Any type of key wrench such as I have desig
nated 20 and illustrated in Figs. 3 and 4 may be
used to operate the screw.‘ The lower end may
be cut so that it will conform to the‘size‘ and
shape of'recesses 3 and 4. This lower end 2|
will then act as a key that will readily fit in
these recesses in head 2 and securely engage
walls 8 and 9 to drive the screw into position,
permitting the turning effort to be e?iciently
transmitted without imposing too great a strain
on head 2. Cutting recesses l3 and I4 in a
manner to form opposite walls ‘I and 8 at a rela
tively small angle, such forinstance as 15°, not
only minimizes the cutting operations but like
wise leaves a maximum amount of material in
the segments 22_ and 23 to prevent destruction
of the head by the key wrench. Moreover, it
provides recesses of such conformation as to
enable key wrench 20 to be readily inserted in
the recesses although the screw may be located
at an inconvenient point to the mechanic.
Without ‘further elaboration, the foregoing will 30
so fully explain the gist of my invention that
others may, by applying current knowledge,
readily adopt the same' for use under varying
conditions 'of service, without eliminating cer
tain features, _which may properly be said to
constitute the essential items of novelty in
volved, which items are intended to be de?ned
and secured to me by the following claims.
I claim:
L'A screw comprising a head and a threaded 40
shank, said head having substantially ?at re
cesses which join at the center of the head, each
recess being substantially a sector extending to
the periphery of the head to provide an open end,
and a locking‘ member of substantially the same
monly used in the art. Irrespective of whether
head/2 is enlarged, it will be noted that the
arcuate edges l5 at each side of key-lock i2 _ cross section as that
will bind against wall It of the countersunk re
be inserted therein
cesses in part l5. Key-lock I2 may be made of walls and the wall of
relatively soft material which will permit it to screw is threaded to
'50 spread when tapped or pounded into recesses 3
and 4.
If key-lock I2 is made of relatively soft ma
terial it may be removed without difficulty. I
suggest providing an opening IT in the center
in ii! where the material is constricted to conform to
the center 5 where recesses 3 and 4 are joined
as previously explained. Hole l1 'enables the
placing of a punch l8 against key-lock l2 so that
it may be readily split or torn apart, starting at
60 the center where hole I1 is, when it is desired
to remove key-lock l2 from the head 2. Any
sharp instrument may be used instead of punch
l8, or any means may be provided to initiate the
quick removal of key-lock I 2 from recesses 3
' and 4. On the other hand, it may not be neces
sary to provide hole I‘! to act as a means of
starting the splitting or tearing action of the key
look at the center to enable removal of the sec~
It will be noted that key-lock l2 provides a
very simple and inexpensive key to lock the screw
of said recesses adapted to
and wedged against their
the member into which said
lock sai-d screw in position.
2. A screw comprising a threaded shank and 50
a head having a substantially ?at recess therein,
said recess being open at ,the edge'of said head,
and a locking member of substantially the same
cross section as that of said recesses and wedged
thcreinto in binding relation with the walls of
said recess and the wall of the part in which said
head is countersunk.
3. A screw to be countersunk in a work piece
comprising a head and a .threaded shank, said
head having substantially flat diametrically op
posed reeesses joining each other in the center,
said recesses being de?ned by side walls extend
ing through the periphery of 'the head to provide
an open end for each recess, and an initially
arcuate locking member flattened into said re 65
cesses in binding relation with the walls thereof
and through the open end in binding relation with
the wall of the work in which said head is coun
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