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Патент USA US2408888

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Oct. 8, 1946.
12, 8,887
vc. A. SCHRINER
‘SCREW DRIVER
Filed June‘18, 1943
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Patented Get.
, 1946
2,488,887
' 1
UNITED STATES PATENT OFFICE‘
2,408,887
SCREW DRIVER
Carl A. Schriner, De?ance, Ohio, assignor of one
half to‘ Lester A. Snyder, De?ance, Ohio
Application June 18, 1943, Serial No. {191,281
5 Claims. (01. 145-50)
1
2
This invention relates to screw drivers and in
particular to screw drivers equipped with means
to grippingly hold the screw prior to and during
driving. There have been proposed a number of
arrangements of springs combined with or form
ing screw drivers for the purpose of grippingly
engaging the kerf of a screw. In general, these
all have considerable length of spring between
the screw kerf and the body of the screw driver
strips I5 which protrude from the slot II in the
end I2 of the shank member III. The resilient
strips I5 are so formed that normally the por
tions within the shank member I0 taken together
resemble a pointed ellipse while the nibs I 4 pro
truding from the slot I I lie together.
The nibs I4 may be formed straight as is indi
cated in Fig. IV or they may be formed with a
The primary object of this invention is to re
duce to a minimum the distance between the tor
sional support for the screw kerf engaging
strips contact each other a short distancev in
small amount of reverse curvature as shown in
and as a result have considerable de?ection and 10 Figs. I and II. It will be observed that in each
loss of grip when driving torque is applied.
, form of the device the oppositely bowed resilient
wardly from their ends, viz., at the upper ends
of the nibs I 4, the contacting portions forming
springs and the screw kerf, thus minimizing the 15 fulcrum means about which the nibs pivot when
torsional de?ection and increasing the strength
the resilient strips are forced together. The re
verse curvature shown in Figs. I and It improves
Another object is to increase the gripping ef
the gripping effect by concentrating the force
feet by suitably shaping the springs to materially
near the bottom of the kerf.
reduce the free length between the support and 20 The strips I5 are placed in the shank member
ID in such manner that the junctions of the
the screw kerf, and to engage the screw near the
bottom of the kerf.
curved portions with the nibs III are in the slot
Another object is to provide a, surface on the
I I. A pin I6 passed through the strips I5 and
end of the screw driver to match the surface of
shank member I0 near the slotted end I2 pre
the head of a screw thus minimizing any tend 25 vents any longitudinal derangement of the parts.
ency toward buckling or misalignment when
For the purpose of forcing toward each other
driving force is applied to the screw.
the portions of the resilient strips I5 forming the
These objects and others apparent to those
elliptical shape and thereby causing the nibs I4 to
skilled in using tools of this nature are attained
diverge for the purpose of gripping the kerf of a
in a screw driver as shown in the drawing in
screw a rod I? having a slotted end portion I8 is
which:
slidab-ly ?tted into the shank member I!) so that
Fig. I is a side view, partly in section, showing
its slotted end portion can be pushed over the
the arrangement of the parts prior to gripping a
elliptical portions of the resilient strips I5. A pin
screw.
IS in the side of the rod I'I cooperates with a slot
Fig. II is a similar View, showing the position
20 in the side of the shank member ID to prevent
of the elements when the screw driver is in grip
twisting and to limit the longitudinal travel of
of the screw driver.
ping engagement with a screw.
the rod II.
A knob 2I 0n the exterior end of
Fig. III is a front view, partly in section, show
the rod I‘I facilitates the manual operation of
ing the elements in the same position as in Fig.
the rod I'I.
‘
II, the screw being omitted.
40
The device is operated by withdrawing the rod
Fig. IV is a side view, partly in section, show
II to the outer limit of its travel allowing the
ing a modi?cation of the invention.
resilient strips I5 to assume their normal ellipti
The preferred embodiment of the invention
cal shape with the ends of the nibs I4 together.
comprises a hollow shank member I0 open at one
In this condition the nibs I4 are inserted into the
end and closed except for a slot II at the other
kerf of a screw and the rod I‘! pushed inward to
end I2. The surface of the closed end I2 is made
the other limit of its travel, thereby flattening
?at to provide a substantial area, in contact with
the elliptical shape and causing the ends of the
the screw head. It is, of course, possible to so
nibs I4 to separate forcibly and grippingly en
shape the end surface to mate with other shapes
gage the screw kerf as shown in Fig. II.
of screw heads to accomplish the same object.
Fig. IV shows a modi?cation of the invention
The exterior of the shank member I0 near the
in which the elliptical shape of the resilient strips
open end may be knurled as at I3 Fig. III or ?tted
I5a is flattened by screw members 22 set in a
with a, handle as shown in Fig. IV.
slidable collar 23 surrounding the tubular shank
The kerf of a screw to be held and driven is
engaged by nibs I4 of a pair of resilient steel 55 member Illa. The screw members 22 extend in
2,408,887
4
a
0
ing bowed away from each other and having por
tions of reverse curvature protruding through the
wardly through slots 24 in the sides of the tubu
lar shank.
The operation of this modi?cation is the same
as that of the preferred embodiment described,
the di?erence being in the substitution of the
This modi?cation materially reduces the required
slot in said tubular member to engage the kerf
in a screw, means preventing longitudinal mo
tion of said strips in said tubular member, said
protruding portions at all times extending be
yond the slotted end of said tubular member a
overall length. It will be noticed that in both
the preferred embodiment and the modi?cation
screw, said slotted end being shaped to closely
collar 23 and screws 22 for the slotted rod II.
distance approximating the depth of a kerf of a
the nibs M or Ma engaging the kerf of a screw 10 overlie the upper face of a screw head engaged
by‘ the protruding portions of said resilient strips,
are torsionally supported by the slot H or Ila
and a slotted member slidably mounted in said
closely adjacent to the head of the screw. Con
tubular member and adapted to force said strips
structed in this manner, the torsional driving ef
together within said tubular member thereby
fort applied to the handle is transmitted to the
resilient strips principally at the nibs [4 or Ila F separating the ends of the reverse curvature por
tions of said strips exterior of said tubular mem
rather than as a twisting force at the upper por
her to grippingly engage the kerf of a screw.
tions of said strips. This construction, there
fore possesses a strength and rigidity heretofore
4. In a screw driver of the class described, in
unattainable in screw drivers of this class.
combination, a hollow tubular member closed at
Having shown this novel form of screw driver 20 one end and having a slot in said closed end,
oppositely bowed resilient strips positioned within
and‘pointed out its advantages, I claim:
said tubular member and having portions of re
1. In a screw driver adapted to grippingly en
verse curvature terminating in nibs protruding
gage a screw, in combination, a hollow tubular
through the slot in the end of said tubular mem
member closed at one end and having a slot in
said closed end, curved resilient strips ?tted 25 ber to a distance approximately equal to the
depth of a screw kerf, means preventing longi
within said tubular member, said resilient strips
being bowed away from each other and having
tudinal motion of said strips with respect to said
portions of reverse curvature protruding through
tubular member, means operating on the portions
the slot in said tubular member to engage the
of’ said strips within said tubular member to ef
kerf in a screw, means preventing longitudinal
fect separation of the ends of the reverse curva
motion of said strips in said tubular member, and
ture portions of said strips exterior of said tubu
a slotted member slidably mounted in said tubu
lar member, said slotted end of said hollow tubu
lar member and adapted to force said strips to
lar member being formed so the slot therein may
gether. within said tubular member thereby sep
be positioned closely adjacent the kerf of a screw
arating the ends of the reverse curvature portions 35 to be driven thereby causing the torsional driving
of- said strips exterior of said tubular member to
effort to be transmitted to the screw by force ap
grippingly engage the kerf of, a screw.
plied to said strips closely adjacent to said nibs.
2. In a screw driver adapted to grippingly en
5. In a screw driver of the class described, in
gage a screw, in combination, a hollow. tubular
combination, a hollow tubular member closed at
member closed at one end and having a slot in 40 one end and having a slot in said closed end, on
said, closed end, curved resilient strips ?tted
positely bowed resilient strips positioned within
within said‘ tubular member, said resilient strips
said tubular member and having end portions in
being bowed away from each other and having
contact with each other a limited distance in
nibs protrudingthrough the slot in said tubular
wardly of their ends and terminating in nibs pro
member to engage the kerf in a screw, said nibs 45 truding through the slot in the end of said tubu
being; in, contact a short distance inwardly of
lar member to a distance approximately equal to
their ends, to form fulcrum means- about which
the depth of a screw kerf, means preventing lon
said nibs; pivot when said bowed strips are forced
gitudinal motion of said strips with respect to
together, means preventing longitudinal motion
said tubular member, means operating on the
of said strips in said tubular member, and a slot 50 oppositely bowed portions of said strips within
ted, member slidably mounted in said tubular
said tubular member to effect separation of the
memberandadapted to force said stripsltogether
ends of the portions of said strips exterior of said
within the slotted portion ofisaid slotted member
tubular member, said slotted end of said tubular
thereby separating the nibsof- said resilient strips
member being formed so that the slot therein
exterior of, said tubular member to grippingly 55 may be positioned closely adjacent the kerf of a.
engage the kerf; ofa screw.
'
screw to be driven, thereby causing the torsional
3. In’ a’ screw driver adapted to grippingly en
driving e?ort to be transmitted‘ to the screw by
force applied to said strips closely adjacent to
gage‘ a screw, in combination, a hollow tubular
member closed at one end and having a_ slot in
said nibs.
said closed end, curved resilient strips ?tted with
CARLA. SCHRINER.
in said tubular member, said resilient strips be
60
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