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Патент USA US2404427

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‘July 23, 1946-\
4 2,404,427
Filed Feb. ' 23, 1944
Patented July 23, 11946‘
Samuel Bloom?eld, Wichita,’ Kans.
Application February 23, 1944, Serial No. 523,519
3 Claims.
(Cl. 145-—50)
This invention relates to hand tools of the
type employed in moving to and from position,
conventional‘kerfed screws, bolts, machine screws
and the like, the primary object being the pro
vision of such an instrumenthaving as a part
thereof, simple, rugged, inexpensive,‘ unique and
e?icient means for gripping the longitudinal side
walls of the kerf _to preclude accidental disen-'
One of the importantraims of the present in
vention is the provision of a hand tool of the
able period of time and much effort has been
expended in solving this aim.
‘The e'xpansible jaw vscrew driver illustrated
herewith and about to be described, has been
found to be e?icient, inexpensive to construct,
andeasy to manipulate.
' a
The conventional screw driver about which
parts. of'the tool embodying the invention may
be assembled, comprises the well-known han
10 dle ill, from which extends a shank l2. In this
aforementioned character that is in the nature
instance, the shank is attenuated, cylindrical
member, ‘uniform in diameter throughout its
of a screw driver having as a part thereof, re
length and with planar inclined, diametrically
silient jaws, movable to engagement with the
opposite faces l4 forming the blade portion of
the tool. An annular groove l6 formed in shank
edges of a screw kerf as torque is applied to the
screw driver shank in either direction about its
longitudinal axis.
Another object of this invention is. to provide
I2 is spaced inwardly from faces M, as illustrated
in Figs.'3 and 4.
The plurality of jaws that are loosely ?tted
an inexpensive hand tool for manipulating screws,
upon shank I2, is, in this instance, a pair of‘
that embodies an assembly of interrelated parts 20 semi-cylindrical jaws l 8 each having an internal
contour conforming to that of the blade portion
at the blade end of the tool, which assembly is
of shank I2 against which they are assembled. A
shifted to and from a normal position through
head ZQis formed within ‘each jaw [8 to enter
the interaction of the manual manipulation of
the tool and the means for yieldably engaging
the said parts.
Other objects of theinvention include the
speci?c manner of constructing the screw driver
, groove [6.5 7'
When beads 20 of the two jaws H? are in the
aforementioned ‘relation with respect to‘ gifOove
IS; the ‘end of the blade formed by the conver
shank, the jaws associatedv therewith, and the
gence of'faces l4, rests immediately. above in
means for yieldably holding the jaws in a nor
, ternal shoulders 22 formed on the jaws. When
mal position, all of which will appear duringvthe
course of the following speci?cation, referring to
‘jaws l8 are so, positioned with respect to each
other and the blade of shank’! 2, the specially
formed split collar 24 is positioned as illustrated
in Fig. 1." This split collar is aresilient annulus
having at least two slits 26 provided therein
the accompanying drawing wherein:
Fig. .1. is a condensed side elevational view of
an expansible jaw screw driver, made to embody
35 that extend inwardly from that edge of collar
the features of the present invention.
,24 adjacent to the free end of shank l2.
Fig. 2 is a fragmentary side elevational view
The slits are designed as illustrated in Fig. 4
of a portion of the tool showing the jaws there
and when in the normal position, these slits pro
of in an expanded condition.v
Fig. 3 is a fragmentary vertical sectional View 40 gressively, increase in width as their inner end
is approached. These‘slits terminate in an en
through that portion of the tool shown in Fig; 2
largement 28, all to the end that" the split collar
but taken on line III--III of Fig. 1.
24 may yieldably yet effectively hold the jaws l8
Fig. 4 is an enlarged stretch-out perspective
in a normal position but allow the expansion of
view of the component parts of the screw driver.
the jaws, as hereinafter set down.
Fig. 5 is an enlarged cross sectional view taken 45
The outer edge of. jaws I8 formed by the meet-.4
on line V-—V of Fig. 1; and
ing of theouter side surfaces thereof and the
Fig. 6 is a similar cross sectional view taken
edge surface at their upper ends, is beveled as
‘on line VI—VI of Fig. 2.
at 3!] to facilitate the placement of split collar One of the greatest problems experienced by
24 when the latter is moved downwardly over jaws
users of screw drivers or similar tools that are 50 l8. The frictional engagement between split col
employed in manipulating kerfed structural hard
lar 24 and jaws l8'will maintain these elements
ware, is the tendency of .the screw driver blade
in a desirable working relation and against rel
to slip from the Vkerf as force is exerted,v about
ative displacement. Well-known means may be
the longitudinal axis of the shank of the tool.
‘utilized to secure collar 24 against longitudinal
This problem has'been prevalent for a consider 55 movement, if desired.
‘claimed’ as new and desired to be secured by Let
Each jaw I8 is specially formed at itskerf en
A relatively short planar- and
knurled area 32 is ground, cast or otherwise
formed to insure a positive grip between the
opposed faces 34 of the kerf of screw‘ 36. These
ters Patent is:
1. A screw driver of the character described
' gaging edge.
comprising, in combination, a handled shank
having a blade; a plurality of jaws loosely ?tted
onto the blade and extending longitudinally
therealong; means on each jaw respectively, to
areas 32 are in parallelism with faces 34 of the’
screw kerf and when the tool is manipulated in
prevent accidental longitudinal displacement of
a normal fashion, these knurled areas 32 will be
the jaws; and resilient means engaging the jaws '
to allow radial movement of the jaws
The operation of the ‘hand tool is obvious from 10 adapted
is applied to the blade, said jaws each
the foregoing speci?cation but it should be
having a shoulder engageable by the end of the
stressed that, advantages arise from the inter- '
blade as longitudinal force in one direction is ap
engagement between internal shoulders 22 and‘
the end of shank I2 formed by the meeting of '
faces l4. When a torque is applied to. causenthe,
plied to rthe'shank during use of the screw driver.
‘ shank to move about its longitudinal axis, sur_
' faces l4will act in a manner graphicallyv illus- ,
2. A_ screw driver of the character described 7
comprising, in combination, a handled shank
having ‘a blade at one end thereof and an annu
trated in Fig. 6, i. e; jaws l8 will be forced from _ lar groove formed therein adjacent to the blade;
a plurality of jaws loosely ?tted; onto the blade
thernormal position shown in Fig. 5 to the condi- - ~
tion shown in Fig. 6, where knurled areas 32 are 20 and extending longitudinally therealong over the
said groove; an internal bead on each jawrespec- _
snugly and ?rmly pressed against the faces ‘340i 7
tively, ?ttedTinto the groove to'preventlongitu
the kerf, Increasing the force of thetorque will
dinal displacement of the jaws; ‘and resilient
amplify the" outward pressure exerted between
means engaging the jaws adapted toallow radial-v
jaws I8 and they will be more'rigidly directedv
against the opposed surfaces‘ 34 to positively‘pre 25 movement ofthe'jaws as torque is applied to the
.blade, each vof said .3‘ aws having a'shoulder formed.
clude accidental displacement.‘ /The, application
on the inner; face thereof engageable by the end
of such torque is sufficient to‘, overcome the ten
of vthe'blade when longitudinalfforce in one direc
sion :of split collar 24 'andiwhen the tool is in
tion is exerted on the screw driver during-use.
operation the condition of jaws ‘l8 and split col
la'r asillustrated in, Fig. 2.. Release of the 30;
_ 3. A screw driver of the character described
torque applying forcerwill permit collar“ to re-‘
comprising, in combination, a >handle,d,~i'attenu
turn jaws l8 to the normal position and the tool
ated, ‘cylindrical shank having a pair of planar
may be removed'from engagement with the screw
diametrically opposed, inclined faces r'forme'd '7
kerfthe same as‘thollgh the gripping jaws were
thereon at one end'thereof; an annular groove
formed in the shank spaced inwardly from the
f-The use of theunique expandible jaws does not"
not present.-
said inclined faces; a pair of opposed jaws each
add to the bulk of the tool to such an extent as
having. a cavity formed-thereincontoured to
to render its, use objectionable, and since the
' snugly ?t a length ofthe shank on each side of.
overall thickness of the screw engaging ends of
"jaws 18 need not be greater than that of conven 40" the groove; a bead on each jaw ?tted into the
groove; a shoulder on each jaw to engage the end
' tional screw drivers,v the tool is usable ‘:wherever
of the shank at the said inclined faces; and re
a-standard screw driver could be employed.
silient means circumscribing the jaws to‘ hold the
' Any tendency'of the operator to exert down
same in place on the shank, the side edges of the
ward pressure on shank l2 will not establish a;
'maladjustmentzbetween the parts. The end‘ of 45; planar faces on the shank serving to spread the
shank; [2 will always rest upon shoulders 22
whether, ‘the jaws are in. the normal position‘ or
spread in work.‘
jaws as torque is applied thereto during operation -
of the screw driver, the end of said shank and
theshoulders on the innerfaces of the jaws being
in engagement to ‘cooperate with the inter-?tted
The preferred embodiment of the invention has been‘ illustrated and such modi?cations and ‘al 50? groove and beads to prevent relative longitudinal
movement of theshank and the jaws when longi
teration in speci?c structure as "are within the
tudinal force in one direction 'is exertedg’on the
' spirit of the invention may be made without de
partingfrom the scope of the‘ appended claims. -
Having-thus described the invention, what is
‘ shank.
seMvEL BLOC-Mime: .
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