Improvements in Flexible Shafts.
Year: 1897

page_text: Date of Application, 16th Mar., 1897-Accepted, 17th Apr., 1897
COMPLETE SPECIFICATION.
Improvements in Flexible Shafts.
I, GEORGE HENRY COATES, of 237 Chandler Street, Worcester, in the County of
Worcester and State of Massachusetts, United States of America, Manufacturer, 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:-
My invention relates to flexible shafts, such as are commonly used in connection
with dental engines, machines for clipping horses, revolving hair brushes and for
similar purposes; said flexible shafts comprising a series of pivotally united links,
which are inclosed in a flexible tube, or covering.
In the following description of my invention and the manner in which the same is
to be performed reference is made to the figures and reference letters in the
accompanying drawings, which represent a portion of a flexible shaft embodying my
invention and showing in detail the construction and arrangement of the several
parts.
Figure 1 represents a portion of a flexible shaft embodying my invention; said
portion comprising three links of the shaft, inclosed in a flexible tube, or covering,
with the links shown in full and the flexible tube, or covering, shown in central
longitudinal sectional view.
Figure 2 represents three of the links of a flexible shaft removed from the outer
covering, or flexible tube, and shown in central longitudinal sectional view.
Figure 3 represents three of the links of a flexible shaft removed from the outer
covering, or flexible tube, and shown in central longitudinal sectional view; but with
the plane of the section at right angles to the plane of the section represented in
Figure 2.
Figure 4 represents a central longitudinal sectional view of two links pivotally
united and at an angle with each other.
Figure 5 represents a central longitudinal sectional view of two links pivotally
united and at an angle with each other, but with the plane of the section at right
angles to the plane of the section shown in Figure 4.
Like parts are indicated in the accompanying drawings by like letters of reference.
A denotes the flexible tube, or covering, which incloses the links of the flexible
shaft; said covering consisting in the present instance of a closely wound spiral
spring A1 covered with a textile fabric, or other suitable flexible material, A 2.
Within the flexible tube, or outer covering, of the shaft are inclosed a series of links
pivotally united at their ends by an universal joint which permits rotary motion
applied at one end of the shaft to be transmitted through the united links to the
opposite end of the shaft notwithstanding that the shaft is slightly bent, bringing
adjacent links at an angle with each other. In Figure 1 of the accompanying
drawings I have represented three of the united links of which the shaft is comprised
the number of links being increased according to the length of the shaft desired.
The links comprising my improved flexible shaft are of two kinds arranged alternately
and pivotally united at their ends; one kind, which I term. barrel links, are denoted
in the drawings by the reference letter B and the second kind, which I term
intermediate links, are denoted in the drawings by the reference letter C, the
intermediate links C serving to connect the barrel links B.

page_text: The barrel links B are composed of a shell made in halves B1, B2 with the central
portion of the shell cylindrical in form and having each end enlarged to form a semi
spherical shell B 3 adapted to receive the end of an intermediate link.
Inclosed within the cylindrical portion of the barrel links B is a cylindrical bar B4
in order to hold the halves B 1, B 2 of the shell concentric. The halves B1, B2 are
united together by rivets B 5 which pass diametrically through the central bar B 4
and are upset, or headed, at their ends.
The intermediate links C consist of a cylindrical bar having spherical or rounded
ends C1 provided with central slots C2 which form ears, or lugs, C 3. A pivotal
pin C4 is held concentrically in the lugs C3 with its axis at right angles with the
plane of the slot C2. Pivoted upon the pin C4 is a rocking bar D having
gudgeons D1, D1 which enter holes D2, D2 in the enlarged or spherical ends B 3
of the barrel links B. The intermediate links C are capable of a rocking motion
about the axes of the pivotal pins C4 and they are also capable of a rocking motion
about the axis of the gudgeons D1, D1 and as the axes of the pivotal pins C4 are at
right angles to the axes of the gudgeons D1; but in the same plane, the pivotal
connection between the ends of the intermediate links C and the ends of the barrel
links B forms an universal joint, so that the rotary motion of one of the barrel
links B will be communicated to its connected intermediate link, when placed at a
slight angle thereto, in the same manner as if the two were in a straight line.
The outer bearing surface of the enlarged or semi-spherical ends B 3 of the barrel
links maintain the links B concentrically within the flexible tube A and as the cross
section of the intermediate link C is less in diameter than the semi-spherical ends of
the barrel links B, the link C will be held out of contact with the flexible tubo A.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. The combination of a series of links L and series of links C alternating with
said links B; said links C baving lugs, or ears, at each end, pivotal pins held by said
lugs, or ears, rocking bars pivoted on said pivotal pins, said rocking bars having
gudgeons at their ends, said gudgeons pivoted in the ends of said links B, as and for
the purpose set forth.
2. The combination of a series of links having lugs projecting from their ends,
pivotal pins held in said lugs, rocking bars pivoted on said pins, and a series of
alternating links pivotally connected with said rocking bars, as and for the purpose
set forth.
3. The combination of a series of links made in halves and having their ends
adapted to inclose the ends of a series of alternating links, a series of alternating links
with the ends of said links pivotally connected, as and for the purpose set forth.
4. The combination of a series of links provided with enlarged ends, a series of
intermediate links having lugs at their ends inclosed in said enlarged ends, bars held
by said enlarged ends and passing between said lugs and pins held in said lugs and
serving to retain the bars between said lugs, as and for the purpose set forth.
5. The combination of a series of links B consisting of a central cylindrical bar B 3,
the shells B1 and B2 held concentrically on said bar and united together, said links
having enlarged ends adapted to enclose the ends of intermediate links, and a series
of intermediate links pivotally united to said enlarged ends, as and for the purpose
set forth.
Dated the Nineteenth day of February 1897