Improvements in parts.
Year: 1897

page_text: Improvements in parts.
I, WILLIAM CLARK, of 528 Oxford Street, W., in the County of Middlesex,
Horse Clipper Manufacturer, do hereby declare the nature of this Invention to be
as follows:-
The said invention relates to an improved mode of constructing flexible shafting
for use in operating drills, animals clippers or shears, dental instruments, or other
tools, or apparatus, in the well known manner.
The improved shafting is formed of a series of very short lengths of shaft con-
nected by universal joints, the whole being, so arranged as to form a continuous
shaft having a smooth exterior surface, and possessing sufficient rigidity to
transmit power,
and capable of transmitting such power either when in a straight
line, or when curved in any required direction.
In practice the lengths of shaft consist of short pieces of tube, each end of each
said piece being formed with two semi-circular projections opposite to each other,
and having similarly shaped semi-circular gaps between them, so that the projec-
tions on one piece fit into the gaps on the next piece. At each such junction, a
disc, or frustrum of a sphere is placed within the tubes, and has four pins equi-
distant from each other on its periphery, entering holes in the four projections
aforesaid, thus forming a universal joint. The said joints being concealed in the
tubes, the shaft has a practically smooth continuous exterior surface, and the
pieces of tube being quite short, the flexibility of the shaft is equal to, if not greater
than, that of the ordinary coiled wire flexible shaft, while it has the great
advantage that no power, beyond the practically negligible friction of the pins in
the joints, is consumed when it is working in a curve. There is less lost motion,
and the liability to breakage is less than in the coiled wire shaft.
The shaft may be enclosed in any suitable form of elastic cover, such as rubber,
or woven or braided material.
.
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page_text: what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:
The said invention relates to an improved mode of constructing flexible shafting
for use in operating drills, animal clippers or shears, dental instruments, or other
tools or apparatus, in the well known manner.
The improved shafting is formed of a series of very short lengths of shaft con-
nected by universal joints, the whole being so arranged as to form a continuous
shaft, having a smooth exterior surface, and possessing sufficient rigidity to trans-
mit power, and capable of transmitting such power, either when in a straight line,
or when curved in any required direction.
In practice the lengths of shaft consist of short pieces of tube, each end of each said
piece being formed with two semi-circular projections opposite to each other, and
having similarly shaped semi-circular gaps between them, so that the projections
on one pieces fit into the gaps on the next piece. At each such junction a disc,
or frustrum of a sphere is placed within the tubes, and has four pins equidistant
from each other on its periphery, entering holes in the four projections aforesaid,
thus forming a universal joint. The said joints being concealed in the tubes, the
shaft has a practically smooth continuous exterior surface, and the pieces of tube
being quite short, the flexibility of the shaft is equal to, if not greater than, that
of the ordinary coiled wire flexible shaft, while it has the great advantage that no
power, beyond the practically negligible friction of the pins in the joints, is con-
sumed when it is working in a curve. There is less lost motion and the liability
to breakage is less than in the coiled wire shaft.
The shaft may be enclosed in any suitable form of elastic cover, such as rubber,
or woven, or braided material.
In the accompanying sheet of drawings, which forms part of this specification,
and in which similar letters of reference denote similar parts throughout:
Fig. 1 is an exterior view, partly in section, of a short length of flexible shaft,
constructed in accordance with this invention.
Fig. 2 is a cross section of the shaft through one of the universal joints at A, A,
and
Fig. 3 is a cross section of the shaft, through B, B, shewing an exterior covering,
or sheathing.
.
The shaft is composed of short lengths of tube C, C, etc., and each end of each
such piece of tube is cut or formed so that two semi-circular projections D, D are
left opposite to each other and divided by similarly shaped semi-circular gaps E, E.
The projections at one end are opposite the gaps at the other end, and the projec-.
tions at the ends of each piece fit into the gaps in the ends of the adjoining pieces.
F, F, etc., are discs, preferably in the form of a frustrum of a sphere, as shewn,
fitting within the tubes at each junction and furnished with four pins H entering
holes in the projections D, and so forming a series of universal joints. The gaps E
are necessarily of slightly larger radius than the projections D which enter them,
to permit the requisite freedom of motion in the joint.
It will be seen that the exterior of the shaft presents a practically Continuous
smooth surface, and if the pins H are a proper fit in the holes, there is substantially
no back lash or lost motion.
The shorter the pieces of tube C are made the greater the flexibility of the shaft,
and the sharper the curve at which it will work.
At the right hand end of Fig. 1, the front half of the tubes is removed in order.
to shew clearly the construction of the universal joints.
If a shaft of this nature is of any considerable length, it has a tendancy to kink,
but this is completely prevented by surrounding it with a single coiled wire
sheath J, and this may again be covered by a rubber or other flexible cover K to
exclude dirt and dust.
This improved shaft requires very little lubricant, but it can readily be applied,
when necessary, by pouring down its interior.

page_text: Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a flexible shaft, the combination of short lengths of tube C having semi-
circular projections D and gaps E engaging with each other, substantially as and
for the purpose herein described and shewn.
2. A flexible shaft, consisting of short lengths of tube C having semi-circular
projections D and gaps E engaging with each other, and connected by universal
joints formed of discs F having pins H entering holes in the projections D, sub-
stantially as and for the purpose herein described and shewn.
3. A flexible shaft, consisting of short lengths of tube C having semi-circular
projections D and gaps E engaging with each other, and connected by universal
joints formed of discs F having pins H entering holes in the projections D, and a
coiled wire sheath J, and flexible cover K, substantially as and for the purpose
herein described and shewn.
Dated this 27th day of October 1907
AMBROSE MYALL,
2 Lancaster Place, London, W.C. Agent for the applicant.