Improvements in Parturition Shears for Veterinary Surgeons' Use.
Year: 1892

page_text: Date of Application, 29th Nov., 1892-Accepted, 14th Jan., 1893
COMPLETE SPECIFICATION.
Improvements in Parturition Shears for Veterinary Surgeons' Use.
We, JAMES CHESTER DRINKWATER, Machinist, and WILLIAM LAWRENCE
DRINKWATER, Veterinary Surgeon, both residing in the City of Mount Clemens,
Macomb County, State of Michigan, United States of America, do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
.
This invention relates more specifically to a veterinary instrument for use in
parturition of horses and other large animals, whereby the medical practitioner is
enabled to dissect the fetus in utero if necessary to prevent great injury or to save
the life of the animal, and the invention consists in the peculiar construction and
arrangement of cutting jaws, and in their combination with mechanical devices for
actuating the same with sufficient force to cut through, all as more fully hereinafter
described and shown in the accompanying drawings, in which,
Fig. 1 is an elevation of our instrument, with the jaws closed.
Fig. 2 is a vertical, central, longitudinal section therein with the jaws open.
Fig. 3 is a detached perspective view of the jaws showing more particularly the
grasping and cutting edges of the same.
A is a frame and preferably tubular of sufficient length to introduce into the
uterus. The outer end of this frame is bifurcated and has pivotally secured therein
the jaws B and B¹. The jaw B has a single knife edge a partly formed with
hook teeth b, and having a concave cutting edge.
The jaw B is bifurcated at its inner end and the jaw B is pivoted in the bifur-
cation. The bifurcated portion is formed with cutting edges c corresponding to
the blade B; and its outer end is grooved to form two cutting edges a between
which the cutting edge of the jaw B enters, the edge of this jaw being likewise
concave. The middle portion of the jaw B' has a single edge with hooked teeth e
formed therein, which is in the same plane as the edge in the jaw B. Each of
the jaws is extended beyond its pivot, and pivotally secured to the toggles C,
which in turn are pivotally secured to a sliding rod D passing centrally through
the frame and projecting out at the rear thereof, terminating in a suitable
handle E.
The rear end of the frame is cut off at right angles and has a lateral offset F
in which is journaled the worm wheel G having an actuating crank handle H.
The rear end of the stem D is screw threaded and carries thereon the nut I
which carries or is formed with a screw wheel J, which engages with the worm G.
The nut is held from longitudinal displacement by a set screw engaging into an
annular groove L, formed in the nut, and anti-friction ball bearings are formed
between the adjacent ends of the frame and nut.
In practice the parts being arranged and constructed substantially as shown and
described they are intended to operate as follows:
By turning the crank handle H, in one direction, (preferably to the right) a
rotary motion is imparted to nut J, through the engagement of the worm and screw
pinion, and as the nut is firmly held in place against longitudinal displacement the
stem D will be drawn rearwardly with great force, thereby closing the jaws.
When the jaws are thus closed the instrument is in the position shown in Fig. 1,
the two jaws closing tightly upon each other and having no projecting edges or
corners so that the two may be introduced without injury, their points inter-
locking.
By reversing the motion of the handle H the jaws are opened out to any desired
extent and then guided by the hand of the operator to the extremity of the fetus

page_text: intended to be cut, another operator meanwhile holding the tool by the handle end
and actuating the handle H in the closing direction of the jaws under the instruc-
tion of the surgeon. The jaws in closing, it will be seen, operate in a twofold
manner, that is the hooked portions of the jaws engaging upon the membraneous
or fleshy portion, and thereby hold the tool firmly to its work so that at the time
the bone is reached no displacement of the jaws can take place, while the motion
is so powerful that it will readily cut through the bone and a clean severance of
the parts can be obtained by the interlocking of the cutting jaws as it will be seen
that the single jaw enters partly within the double jaw, and it is thereby prevented
from springing out of line, insuring a clean cut.
It will further be seen that a constant increasing force is obtained by the
spreading of the toggles in the closing movement of the jaws which thereby
increases the power greatly.
The special feature and spirit of our invention consists primarily in the peculiar
arrangement of the jaws, whereby the object to be bisected is forcibly grasped.;
second, in the action of the toggle to increase the power; third, in the appli-
cation of the worm gear for actuating the jaws with sufficient power to cut through
bones.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
1. In a veterinary surgical instrument, the combination with a handle, of two
movable jaws pivoted to the handle, one jaw having two parallel cutting edges at
its outer end, and an intervening space between the edges, and the other jaw
having a single cutting edge at its outer end arranged to enter the space between
the outer cutting edges toothed sections on both jaws, below the cutting edges, and
means for actuating the jaws, substantially as described.
2. In a veterinary surgical shears, the combination of a handle or frame, the
jaws pivoted at the end, the toggle lever connected to the jaws, the shaft D;
connected to the toggle levers and extending through the handle, the nut I
having worm gear wheel J thereon having a screw threaded aperture through
which the shaft engages, the worm pinion G, and the crank H, substantially as
described.
Dated this 31st day of October 1892.
JAMES CHESTER DRINKWATER.
WILLIAM LAWRENCE DRINKWATER.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicants.