LOCKING DEVICE ON A PLIERS SHAPED TOOL

SECURITE POUR OUTIL EN FORME DE PINCE

English Abstract

The locking device for a pliers-shaped tool, preferably a
pair of pliers (1), has a lever (7) with a spring (8a) on the
inner side of the first handle (4a). It has a shaped rod (9) on
the inner side of the second handle (4b).
The shaped rod (9) has a catching device (10) and goes
through an opening (14) in the lever (7). The lever has a sharp
projection (15) in its opening (14), which engages the catching
device (10) of the shaped rod (9) in the closed setting in such a
way that the pliers (1) can only be closed. With these pliers
(1), objects (5) can be gripped, held tight and let loose again.
The locking device in its entirety is placed between the handles
(4a and 4b) of the pliers (1). The pliers (1) with the locking
devices can be used generally as a tool, but their primary
application is in surgery.

Claims

CLAIMS
1. In a pliers-shaped tool having jaws, a first handle
having a first end connected to a first jaw and a second end
remote from said first jaw, a second handle having a first end
connected to a second jaw and a second end remote from said
second jaw, a locking device positioned completely between
said handles and extending longitudinally of said handles to a
point which is nearer to said jaws than are the second ends of
said handles, said locking device, in its entirety, being
positioned nearer to the jaws than are the second ends of said
handles and further comprising a griping mechanism, movable to
different settings, on said first handle, and a shaped rod
having a catching device on the inner side of the second
handle, said gripping mechanism comprising a flat spring
adjacent said first handle, and a lever having an angled side
with two adjoining plates facing the first handle, said lever
being positioned so that in an open setting position one of
said surfaces abuts said spring and in a closed setting
position the other surface abuts said spring whereby said
spring acts to bring the lever back to said open or closed
setting position from other positions, the lever and the
shaped rod being positioned between the two handles, said
lever further having a through hole to receive the shaped rod,
and a sharp projection associated with said through hole to
engage the catching device when said lever is in its closed
setting position, thus permitting the pliers only to be
closed, the through hole having surfaces between which the
shaped rod can move freely when the lever is in the open
setting position so that the pliers can be opened as well as
closed.
2. In a pliers-shaped tool having jaws, a first handle
having a first end connected to a first jaw and a second end
remote from said first jaw, a second handle having a first end
connected to a second jaw and a second end remote from said
second jaw, a locking device positioned completely between
said handles and extending longitudinally of said handles to a

point which is nearer to said jaws than are the second ends of
said handles, said locking device, in its entirety, being
positioned nearer to the jaws than are the second ends of said
handles and further comprising a gripping mechanism movable to
different settings on said first handle, and a shaped rod
having a catching device on the inner side of the second
handle, said gripping mechanism comprising a lever, the lever
and the shaped rod being positioned between the two handles,
said lever having through hole to receive the shaped rod, said
lever being configured to assume an open setting position and
a closed setting position and having a sharp projection
associated with said through hole to engage the catching
device when said lever is in its closed setting position, thus
permitting the pliers only to be closed, the through hole
having surfaces between which the shaped rod can move freely
when the lever is in the open setting position so that the
pliers can be opened as well as closed, said locking device
further comprising an S-shaped spring on said second handle
urging said tool toward an open position, said spring having
an aperture to accommodate the shaped rod.
3. The locking device claimed in claim 2 and comprising
means pivotally attaching said shaped rod to the second
handle, said rod extending through the aperture in said spring
and the through hole in said lever and said spring being
shaped to press the lever against the first handle through the
rod.
4. The locking device according to claim 3 and comprising a
sliding pad, said spring acting on the shaped rod by means of
said sliding pad.
5. In a pliers-shaped tool having jaws, a first handle
having a first end connected to a first jaw and a second end
remote from said first jaw, a second handle having a first end
connected to a second jaw and a second end remote from said
second jaw, a locking device positioned completely between
said handles and extending longitudinally of said handles to a
point which is nearer to said jaws than are the second ends of

said handles, said locking device, in its entirely, being
positioned nearer to the jaws than are the second ends of said
handles and further comprising a griping mechanism movable to
different settings on said first handle, and a shaped rod
having a catching device on the inner side of the second
handle, said gripping mechanism comprising a lever, a crescent
shaped slot in said lever, and a pin seated in said slot and
connecting said lever to said first handle, the lever and the
shaped rod being positioned between the two handles, said
lever having a through hole to receive the shaped rod, said
lever being configured to assume an open setting position in
which said pin is seated at the end of said crescent shaped
slot nearer to said jaws, and a closed setting position in
which said pin is in a section of the slot more remote from
the jaws and a sharp projection associated with said through
hole to engage the catching device when said lever is in its
closed setting position, thus permitting the pliers only to be
closed, the through hole having surfaces between which the
shaped rod can move freely when the lever is in the open
setting position so that the pliers can be opened as well as
closed, said locking device further comprising a spring on
said second handle urging said tool toward an open position.
6. In a pliers-shaped tool having jaws and handles adapted
to be held by a human hand, a first handle having a first end
forming a first jaw and a second end remote from said first
jaw, a second handle having a first end forming a second jaw
and a second end remote from said second jaw, means pivotally
attaching said handles to one another at a pivot point, a
locking device positioned completely between said handles and
extending longitudinally of said handles to a point which is
nearer to said pivot point than are the second ends of said
handles, said locking device, in its entirety, being
positioned nearer to the jaws than are the second ends of said
handles and further comprising a gripping mechanism movable to
different settings on said first handle, and a shaped rod,
having a catching device, on the second handle, said griping
mechanism comprising a lever, the lever and the shaped rod
being positioned between the two handles, said lever having a

through hole to receive the shaped rod, said lever being
configured to assume an open setting position and a closed
setting position and having a sharp projection associated with
said through hole to engage the catching device when said
lever is in its closed setting position, thus permitting the
pliers only to be closed, the through hole having surfaces
between which the shaped rod can move freely when the lever is
in the open setting position so that the pliers can be opened
as well as closed, said shaped rod being pivotally attached to
the inner side of said second handle at a point nearer to said
pivot point than to the second ends of said handles.
7. The locking device claimed in claim 6 and comprising a
spring on said second handle, said spring urging said tool
toward an open position.
8. The locking device according to claim 7, wherein said
lever is shaped so that in the closed setting it is
perpendicular to the shaped rod.
9. The locking device claimed in claim 8, wherein the
catching device on the shaped rod has perpendicular surfaces
facing the end of said handles remote from the jaws.
10. The locking device claimed in claim 7 and wherein said
spring is S-shaped and comprises an aperture for accommodating
the shaped rod.
11. The locking device claimed in claim 10 and comprising
means pivotally attaching said shaped rod to the second
handle, said rod extending through the aperture in said spring
and the through hole in said lever and said spring being
shaped to press the lever against the first handle through the
rod.
12. The locking device according to claim 11 and comprising a
sliding pad, said spring acting on the shaped rod by means of
said sliding pad.

13. The locking device according to claim 6, wherein the
shaped rod has a circular cross section, and the catching
device comprises periodically placed ring grooves.
14. The locking device according to claim 6, wherein the
shaped rod has a cross section with at least two edges, and
the catching device comprises a toothed rack.
15. The locking device claimed in claim 6 and comprising a
flat spring adjacent said first handle, said lever having an
angled side with two adjoining planes facing the first handle,
said lever being positioned so that in the open setting
position one of said surfaces abuts said spring and in the
closed setting position the other surface abuts said spring
whereby said spring acts to bring the lever back to said open
or closed setting position from other positions.
16. The locking device claimed in claim 6 wherein said lever
and said rod are positioned so that said lever can be moved
between said open and closed positions by a hand holding said
handles.
17. A retrofit kit for a pliers-shaped tool having jaws and
handles adapted to be held by a human hand, including a first
handle having a first end forming a first jaw and a second end
remote from said first jaw, a second handle having a first end
forming a second jaw and a second end remote from said second
jaw, said handles being pivotally attached to one another at a
pivot point, said kit comprising a locking device, means for
positioning said locking device completely between said
handles to extend longitudinally of said handles to a point
which is nearer to said pivot point than the second ends of
said handles, so that said locking device, in its entirety, is
positioned nearer to the jaws than are the second end so said
handles and further comprising a gripping mechanism for
attachment to said first handle and movable to different
settings, a shaped rod having a catching device and means for
attaching said shaped rod to the second handle, said gripping
mechanism comprising a lever, said lever having a through hold

to receive the shaped rod, said lever being configured to
assume an open setting position and a closed setting position
and having sharp projection associated with said through hole
to engage the catching device when said lever is in its closed
setting position, thus permitting the pliers only to be
closed, the through hole having surfaces between which the
shaped rod can move freely when the lever is in the open
setting position so that the pliers can be opened as well as
closed, and means for attaching said shaped rod pivotally to
the inner side of said second handle at the point nearer to
said pivot point than to the second ends of said handles.
18. In a pliers-shaped tool having jaws, a first handle
having a first end forming a first jaw and a second end remote
from said first jaw, a second handle having a first end
forming a second jaw and a second end remote from said second
jaw, means for pivotally attaching said handles to one another
at a pivot point, a locking device positioned completely
between said handles and extending longitudinally of said
handles to a point which is nearer to said pivot point than
are the second ends of said handles, said locking device, in
its entirety, being positioned nearer to the jaws than are the
second ends of said handles and further comprising a gripping
mechanism movable to different settings on said first handles,
and a shaped rod having a catching device, on the inner side
of the second handle, said gripping mechanism comprising a
lever, the lever and shaped rod being positioned between the
two handles, said lever having a through hole to receive the
shaped rod, said lever being configured to assume an open
setting position and a closed setting position and having a
sharp projection associated with said through hole to engage
the catching device when said lever is in its closed setting
position, thus permitting the pliers only to be closed, the
through hole having surfaces between which the shaped rod can
move freely when the lever is in the open setting position so
that the pliers can be opened as well as closed, said rod
being pivotally attached to the inner side of said second
handle and extending toward the second ends of said handles.

Description

" b
1 .6.A40
LOCKING DEVICE FOR A PLIERS-SHAPED TOOL
The invention involves a locking device for a pliers-shaped
tool according to the introductory clause of Patent Claim 1. The
locking device operates to grip the pliers-shaped tool onto an -~ ~
object, to keep it gripped onto it, and to loosen it again. ~s ~-
A pliers-shaped tool consists of two handles which are
movable against each other about a pivot point. On one side of ~ q~
the pivot point, the handles, each having a lip, form jaws. On
the other side, each handle is configured as a grip, possibly
with finger holes. The invention will be explained based on
pliers as the most common pliers-shaped tool.
Locking devices for pliers-shaped tools are already well
known.
Pliers exist in which a movable long screw is found in a
handle, which passes through a hole in the other handle. A nut
on the outer side of the other handle is threaded onto the screw
after the jaw of the pliers has gripped an object, so that the
object is firmly held by the jaw of the pliers. The object is
then freed when the nut is sufficiently loosened. This -
contrivance is applicable even if the pliers is designed to be
very rigid, owing to the continuous threading capacity of the nut
for any given diameter of the object within the jaw width of the
pliers. However, it requires two hands for operation. The screw - -~
projects beyond the area of the handle; thus, applicability of
such pliers in conditions where space is limited as, for example
in surgery, is restricted.
; ~

I
Another type of pliers has strip-shaped pieces that move
against each other on the inner side of each of the handles.
These strip-shaped pieces move past each other in close
proximity. On the sides that face each other, the strips have ~ ;
numerous triangular-shaped projections, so that the handles are
able to be locked by hooking the trianguIar projections on the
strips at various distances from each other. With pliers made to
he pliable and elastic, for example with long handles, all
objects that are within the maximum jaw width of the pliers can ~-~
be gripped tight, with the gripping pressure differing according
to the position of the handles. hetting the object go using one ~;
hand is possible only if the handles, like scissors, having ~ ;
finger holes at the ends. In letting the object go from the
pliers, the release of the handle-bracing transverse to the
direction of opening necessitates a certain physiologically
unnatural expenditure of energy. ~;
Yet another locking device for a pliers is described in
W089/06939. In this type of pliers, one of the handles has a
toothed rack on its inner side between the pivot point and the
grip. The rack goes through an opening in the second handle. At
the opening of the second handle there is a safety catch which
acts on the toothed rack by means of three different settings.
In its first setting, the pliers can only be closed. In the
second setting, the pliers can only be opened. In the third
setting, the pliers can be either closed or opened in an
unimpeded manner.
' " ' ' ' . . ' ! .. .. .

J .
In the first setting, the pliers grip an object as long as
their jaw is adjusted to the object's diameter. They let the
object go if another setting is made. The settings are made on a
switching mechanism coaxial with the safety catch. They are held
upright by a ball located on a compression spring which at any
given time engages one of the three settings in the safety catch.
These pliers can be operated one-handed. But they require that
the toothed rack extends through the second handle into the ~ ;
external space of the pliers, thus taking up much space like the
first set of pliers mentioned above with the screw.
This invention has the intention of creating a plier-shaped
tool possessing a locking device that is located within the
pliers, but can nonetheless be operated simply and safely using
only one hand. -~
This intention will be achieved by the features presented in ;
the characteristics section of Patent Claim 1. The additional
claims have to do with advantageous design configurations.
An example of the invention will be explained using
illustrations. The following are shown:
Fig. la: Pliers with a locking device in an open setting
with a close up of the lever portion;
Fig. lb: The same pliers in the closed setting;
Fig. 2: A catching device in the form of a toothed rack
with a shaped rod having a rectangular cross section;
Fig. 3: A catching device in the form of turned grooves
with a shaped rod having a circular cross section;
: :'
3 ~ ~
:.

~ , _ /J ~
Fig. 4a: Pliers with another locking device in the closed
position; -~
Fig. 4b: A cross section through the portion around the
lever of ~ig. 4a in the open position;
Fig. 4c: A cross section as in Fig. 4b in the closed
position.
In the illustrations the same component parts that appear
multiple times in the various figures are labelled by identical
reference numbers.
Fig. la shows a pair of pliers 1 according to the invention
in a setting (open setting) in which their handles 4a and 4b are
freely movable about the pivot point. Fig. lb shows these pliers
in a setting (closed setting) in which their handles 4a and 4b
can only be closed.
In pliers 1 one notes the jaws 2, whose halves 3a and 3b
here have teeth. Also notable are the two handles 4a and 4b,
both ending in finger holes lla and llb on the gripping side. To
use the pliers 1, one must put the thumb and middle finger
through each finger hole lla and llb, and operate a lever 7 (to
be described later) using the index ~inger. In Fig. lb, which
shows the pliers 1 in the closed position, an object 5 is
embraced by their ~aws 2.
On these pliers 1, the inner side of the second handle 4b, a
shaped rod 9 is swivel-mounted by means of a pin 6b. On it is a
catching device 10, i.e., an array of periodically arranged
shapes which will be described further on using examples. In
addition it has a lever 7 attached to the inner side of the first
, . ' ~' ',

_ CA 02089407 1998-12-15
handle 4a by a pin 6a. This lever 7 is depicted separately in
both Fig. la and lb.
The lever 7 and the shaped rod 9 are situated in their
entirety between the handles 4a, 4b and do not project outward
beyond them at any point. The lever 7 has an opening 14 through
which the shaped rod 9 runs. It is so configured that it can
assume only two stable settings, an open setting and a closed
setting. In the example given, this is achieved by having its
end that faces the handle 4a formed in an angled configuration
and adjoining a flat piece of a leaf spring 8a. In all
intermediate settings, it is brought back by the spring 8a to the
open setting or the closed setting.
At its opening 14, the lever 7 has a sharp projection 15
with which it grips the catching device 10 of the shaped rod 9.
This gripping takes place in such a way that the pliers 1 can
only be closed. To achieve this, the shaped rod 9 is configured
so that the lever 7 and the side of its projection 15 that faces
the grip is always perpendicular or nearly perpendicular to the
shaped rod 9 in the closed position.
The modules of the catching device 10 of the shaped rod 9
likewise have an edge that runs perpendicular to the direction of
the shaped rod 9, and are always pointed toward the grip side of
the handles 4a and 4b. Behind them the sharp projection 15 of
the lever 7 catches hold, and by this means the lever 7 can no
longer be displaced toward the grip side of the handles ~a and
4b. If an object 5 is in the jaws of the pliers 1, then it is

CA 02089407 1998-12-1~
gripped tight as soon as the jaws 2 have closed over the object,
and then it is automatically held fast by the pliers 1.
In the open setting, the shaped rod 9 lies on a broad
surface. It can then run freely through the opening 14, and the
pliers 1 can be opened and closed without restriction. An object
5 which is held fast in the jaws 2 of the pliers 1 can be let go
when the lever 7 is brought into the open position by a finger of
the operating hand.
Examples for the configuring of the catching device 10 on
the shaped rod 9 are shown in Fig. 2, in which a rectangular
shaped rod 9 is used for the toothed rack, and in Fig. 3, where
the shaped rod 9 has a circular cross section and is provided
with turned incisions in the form of ring grooves. But the
shaped rod can also be configured to have a screw thread or other
suitable forms. In all cases the shapes of the catching device
10 are configured asymmetrically, with an edge running
perpendicular to the direction of the shaped rod 9, and arrayed
in the direction of the grips.
Fig. 4a shows another configuration of the invention-
specific pliers 1 in the closed setting. Fig. 4b shows the
section around its lever 7 in the closed setting. Fig. 4c shows
the section around its lever in the open setting. All three
figures will be reviewed together.
In the open setting of the lever 7, the shaped rod 9 moves
without restriction in the opening 14 of the lever 7, and the
pliers 1 can be opened and closed. The shaped rod 9 is flexibly
attached to the second handle 4b of the pliers 1 by means of the
.

CA 02089407 1998-12-1~
lever 7. It does so with the help of a suitably shaped spring 8b
(in this case, S-shaped), guided by a sliding pad 13. Thus the
pliers 1 tend to open to the maximum extent possible and can only
be closed by pressing the handles 4a and 4b toward each other.
By means of this forcing the pliers 1 to open, the locking
device can be designed differently from what is described above.
The lever 7 has a crescent-shaped slot hole 16 in which moves the
pin that connects the lever 7 with the first handle 4b. Here
also, the lever 7 may assume two stable settings. In the open
setting, the pin 6a is seated in the section of the slot hole 16
which is closer to the jaws as shown in Fig. 4b. Owing to the
tension which the spring 8a exerts on the shaped rod 9, the
latter is pushed toward the side of the opening 14 in the lever 7
that faces the first handle 4a, and it runs freely on a broad
surface of the opening 14.
If one places the lever 7 in the closed setting, the pin 6a
moves over to the section of the slot hole 16 that is closer to
the grip end, and the lever 7 stands nearly perpendicular on the
formed rod. 9. The sharp projection 15 in the opening 14 of the
rod 7 can now engage the catching device 10 of the shaped rod 9
and permits the pliers 1 to close only. The lever 7 is thus
capable of assuming only two stable settings, the closed setting
and the open setting. The remaining parts of the pliers 1 have
the same designators and perform the same functions as in Figs.
la and lb.
The pliers 1 thus automatically grip an object 5 (not shown)
in their jaws 2, if in the closed setting they have been closed

CA 02089407 1998-12-1~
to a sufficient extent that the object 5 is gripped by the jaws
of the pliers. They can let it loose again if the lever 7 is
shifted to the open position by a finger of the operating hand.
With an invention-specific locking device of which examples
are shown in Figs. la, lb and 4a, the lever 7 has an opening 14
through which the shaped rod 9 runs, which has a catching device
10. The lever 7 and the shaped rod 9 are positioned so as to be
between the handles 4a and 4b in their entirety. The lever 7 is
configured in such a way that, owing to spring pressure, it can
assume only two stable settings, an open setting and a closed
setting. Within the opening 14, the lever has a sharp projection
15, with which, in the closed setting, it engages the catching
device 10 of the shaped rod 9, so that the pliers 1 can only be
closed. In contrast, in the open setting, the shaped rod 9 moves
over the broad surface of the opening 14 on the lever 7, so that
the pliers 1 can be freely opened and closed.
The locking device according to the invention can also be
used with pliers 1 in which, for example, the jaw width and the
shape of the jaws 2 can be varied using a slotted hole at the
pivot point between the two handles 4a and 4b (so-called self-
centering pliers).
Naturally, locking devices according to the invention that
are created as kits for retrofitting pliers-shaped tools, also
are within the scope of this invention.
The locking device according to the invention achieves the
stated intention, since it makes possible one-handed operation of
pliers-shaped tools, and is configured to be entirely between the
. .

CA 02089407 1998-12-15
handles 4a and 4b of the pliers-shaped tool. Pliers-shaped tools
equipped with it can be used generally in industry and by
domestic users, but above all they are useful in surgery.

Representative Drawing