Improvements in Equine Dental Rasps.
Year: 1892

page_text: Date of Application, 26th Nov., 1892
Complete Specification Left, 13th Apr.. 1993-Accepted, 13th May, 1893
PROVISIONAL SPECIFICATION.
Improvements in Equine Dental Rasps.
CHARLES HENRY HUISH Surgical Instrument Maker 31 Mundania Road
Honor Oak S.E. do hereby declare the nature of this invention to be as
follows:-
A modified and improved form of the equine dental rasp invented by me
in 1883 called "The Duplex "which instrument being unpatented may be described
as follows.
•
Prior to the introduction of the Duplex all such instruments used for the
purpose of removing jagged portions of horses teeth were made to cut only one
way, the result of this arrangement being that they only removed portions of the
jagged molars being operated upon when the rasp was pushed forward by the
operator the backward movement accomplishing no work whatever.
In other words fifty per cent. of the time and energy of the operator was wasted.
In the Duplex this large portion of lost time and energy is obviated by reason,
that it gives equal results both by the forward and backward movement of the
operators arm this being accomplished on account of its rows of teeth being cut
alternate ways longitudinally and close together.
The Duplex rasp however as well as the old kind looses half an inch laterally
and longitudinally of its working plane inasmuch as its guards are rivetted on to
the rasping surface of the instrument thus occupying space which is utilised by
about two hundred teeth in the improved rasp for instead of having two guards
rivetted upon the surface one guard or flange is only retained and this is obtained
by turning a portion of the rasp blade down from itself instead of rivetting separate
strips of steel upon the workable surface. This will be called No. 1 rasp. In the place
of the ordinary wooden handle hitherto a part of all equine dental rasps another
rasp is joined by means of a screw end which fits into the threaded socket of its
companion and this rasp (No. 2) has its guard on the opposite side to its fellow
which gives a double or reversible duplex rasp or in other words two duplex rasps
in one.
.
As it is also a convenience to have a separate rasp of different shape for the
front molars an " Angle" rasp No. 3 has been devised and this fits into the screw
socket of No 1. The Angle rasp is similar to its companions No. 1 & 2, excepting
that instead of being straight it has an angle of about 45°..
The utility of this reversible arrangement will also be further extended to
another modification by screwing together two grooved frames into which will
slide the rasp plates which will be cut on both sides.
These plates will be fixed by means of a screw through a narrow bar of steel
running from one arm of the frame to the opposite side.
This bar will also serve the purpose of preventing the arms springing open when
the rasp is being used.
This grooved frame arrangement will give four reversible rasps in one and afford
an economical method of renewing the rasp plates when they are worn out.
Dated this Nineteenth day of November 1892.

page_text: COMPLETE SPECIFICATION.
Improvements in Equine Dental Rasps.
I, CHARLES HENRY. HUISH, Surgical Instrument Maker, of 31 Mundania
Road, Honor Oak, S.E., 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, reference being had to the accom-
panying drawings and to the figures and letters marked thereon :-
In the accompanying drawings
Figure is a face view of the old style of equine dental rasp, which cuts only in
one direction.
Figure 2 is a face view of an improved form of such rasp, known as the
Duplex.
Figure 3 is a cross section through either of such rasps.
Figure 4 is a face and back view respectively of a pair of my present improved
rasps.
Figure 5 is an edge view and Figures 6 and 7 are cross sections of the same.
Figure 8 is an edge view of one of my improved rasps for use on the front
molars.
Figure 9 is a back view and Figure 10 is a cross section of a modified form of
my improved rasp, Figure 11 represents an edge view of two of such rasps with
their stems screwed together, and Figure 12 is a plan of a rasp frame such as
that used in the rasp shown at Figures 9, 10, 11 but with the rasp plate removed
therefrom.
I will first describe the equine dental rasps hitherto in use and afterwards I will
describe my present improvements.
A modified and improved form of the equine dental rasp was invented by me
in the year 1883 and is known as the "Duplex." This instrument being unpatented
may be described as follows:-
Prior to the introduction of the "Duplex" equine dental rasp, all such instru-
ments, used for the purpose of removing jagged portions of horses teeth, were
made to cut only in one direction, as will be seen by a face view of one of such
rasps, see Figure 1, the result being that they only removed portions of the jagged
molars operated upon when the rasp was pushed forward by the operator, the
backward movement accomplishing no work whatever. In other words a large
percentage of the time and energy of the operator was wasted.
In the "Duplex" rasp, see Figure 2, this large portion of lost time and energy
is avoided by reason that it gives equal results both by the forward and backward
movement of the operator's arm, this being accomplished by its rows of teeth being
cut alternate ways longitudinally and close together.
The "Duplex" rasp however, as well as the older kind, loses half an inch
laterally and longitudinally of its working plane, inasmuch as its guards a, a, see
Figures 1, 2 and 3, are rivetted on to the rasping surface of the instrument, thus
occupying space which is utilized by a considerable number of teeth in my improved
rasp, for instead of having two guards a rivetted upon the rasping surface, one
guard or flange a is only retained in the forms of my improved rasp shown at
Figures 4 to 7, and this guard or flange a is obtained by turning a portion of the
rasp blade down from itself instead of rivetting separate strips of steel upon its
working surface.
One of these improved rasps will be formed with a screw socket in the end of
its stem or shank b. This rasp I will call No. 1 rasp. In place of using the
ordinary wooden handle hitherto a part of all equine dental rasps, another rasp,
No. 2, is joined to No. 1 rasp by means of a screw 62 at the end of its stem or
shank b which fits into the threaded socket b¹ of its companion or No. 1 rasp, and
this rasp No. 2 has its guard a ou the opposite side to that of its fellow or No. 1

page_text: rasp, which gives a double or reversible “duplex” rasp, or in other words two
"duplex" rasps in one.
As it is also a great convenience to have a separate rasp of different shape for
the front molars; I have devised an Angle rasp, No. 3, the screwed stem or
shank of which fits into the screw socket of No. 1 rasp.
The Angle rasp No. 3 is similar to its companions Nos. 1 and 2, excepting that
instead of the rasp being straight or nearly so with its stem or shank it has a con-
siderable angle with it (see Figure 8).
This rasp. is made without guards a as such are not required for the front
molars.
The utility of this reversible arrangement I have also extended to another
modification represented at Figures 9 to 13 by screwing together the stems or
shanks 6 of two grooved frames a* one frame being made to receive a double plate
for the back molars and the frame at the opposite end being for angle rasps for the
front molars.
Into these grooved frames the rasp plates c, which have teeth cut on both sides
thereof easily slide. These plates c are fixed in position by a screw d passed
through a narrow bar e extending from one arm of the frame to the opposite arm
and formed in one therewith.
This cross bar will hold the arms of the frame a* secure against springing open
when the rasp is being used. The cross bar e may however be fixed in position in
any other suitable manner.
This arrangement of double rasp with grooved frames a' will give two reversible
rasps, that is four rasps in one instrument, namely, two rasps for back molars and
two for the front molars as previously described and afford an economical method
of renewing the rasp plates c when they are worn out. The arms of the frame a*
also act as guards to the edges of the rasps.
I prefer to cut the front of the rasp plate c with teeth of different size to those
of the back thereof.
In the drawings only a few teeth are represented at one end of each rasp, it will
however be understood that the teeth extend along the entire surface of the rasps.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
1. An equine dental rasp having a single guard along one edge thereof made in
one piece with the rasp, substantially as herein shown and described and for the
purpose stated.
2. The combination of two equine dental rasps in one double instrument by
screwing the stems or shanks of the two rasps together substantially as herein
shown and described.
3. An equine dental rasp formed of rasp plates cut with a rasp surface on both
sides, a frame formed with grooved arms to receive such rasp plates, a cross bar
extending from one arm to the other of such frame, and a screw passing through
such cross bar and screwing into the rasp plate, substantially as herein shown and
described.
C. H. HUISH,
By Harris & Mills,
23, Southampton Buildings, London, W.C., Agent..