IMPROVED COM- BINED CHAIR AND TREADLE MECHANISM FOR OPERATING SEWING AND OTHER MACHINES
Year: 1878

page_text: LETTERS PATENT to Alexander Melville Clark, of Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVED COM-
BINED CHAIR AND TREADLE MECHANISM FOR OPERATING SEWING AND OTHER
MACHINES." A communication from abroad by Joseph Boykin Underwood,.
of Fayetteville, Cumberland County, State of North Carolina, United States of
America, and John Dawson Smith, also of the United States of America.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 20th November 1878.
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVED COMBINED CHAIR AND TREADLE MECHANISM FOR
OPERATING SEWING AND OTHER MACHINES." [A communication from abroad by
Joseph Boykin Underwood, of Fayetteville, Cumberland County, State of North
Carolina, United States of America, and John Dawson Smith, also of the United
States of America.]
The object of this Invention is to reduce the muscular force exerted in driving
sewing or other machines operated by a treadle, and to transfer the strain from the
muscles of the abdomen and other parts, which are injuriously affected thereby, to
other muscles which are better able to exert the power and withstand the fatigue,
thus confining the work to the lower part of the legs and converting a laborious
and injurious operation into one of healthful exercise. The Invention cousists in so
pivoting the chair and arranging it upon springs that it shall have a compound
vibratory motion, which adapts it to the movement of the operator, and in utilizing
this movement by connecting with the chair a pendant lever frame projecting
from and rigidly attached to the chair, which frame converts the movement of the
chair into a reciprocating movement of the treadle through a connecting rod, and
operates in conjunction with the natural foot movement upon the treadle.

page_text: In carrying out the Invention the hind legs of the chair are pivoted to base
bars, which extend forwards beneath and have notches to receive the treadle axis
and hold the chair in the desired proximity to the treadle. Springs are placed
beneath the front legs of the chair, which perunit the chair to rock on the hind leg
pivots. The chair seat is also pivoted to the top of the leg frames, which gives to
the seat of the operator a second point of oscillation. To the under side of the seat
a downwardly projecting lever arm or frame is connected, and its lower end which
descends to the level of the treadle and is jointed adjustably to a horizontal
connecting rod that is jointed at its forward end to a short arm projecting
from the lower side of the treadle or from a saddle plate consisting of a plate arched
to pass around the treadle axis, and provided at opposite sides of said arched portion
with flat bearing faces perforated with numerous holes to permit the saddle to be
bolted to the underside of the treadle.
The operation of the devices would be as follows, the toe of the treadle being
elevated :-
When seated in the chair the centre of gravity of the operator is in the rear of
the seat pivots, and the chair seat by its lever connections transmits its lifting force
to the front side of the treadle, thus lifting up the toe of the foot. No muscular
effort is therefore required to depress the heel of the treadle. When the operator
presses with the toe upon the treadle this muscular exertion throws the weight of
the body upon the thighs and shifts the centre of gravity forward of the seat
pivots, causing a compression of the springs, a rocking forward of the whole chair
upon its hind leg pivots, and of the seat on its pivots, whereby the seat by its lever
connections with the treadle tends in conjunction with the toe pressure to bring the
toe of the treadle down. In depressing the heel of the treadle the weight of the.
body is again shifted to the rear of the seat pivots, the chair moves backwards on
the leg and seat pivots, and an effect is produced upon the treadle in harmony with
the downward. movement of the heel portion.
In order to make the seat of the chair adjustable as to height the chair leg frame
may have vertical grooves or guides, in which slotted bars may be adjustably
secured by a bolt, the chair seat being pivoted to the top end of these slotted
bars. According to another means of adjustment the lever frame connected to the
treadle, as before mentioned, instead of being attached to the seat itself is rigidly
attached to a cross bar pivoted at. its ends to the top of the chair leg frames, and
the seat of the chair is provided with an elevating screw stem, which turns in a nut
in the cross bar like a music stool.
The springs of the chair instead of being placed beneath the front legs may be
placed at any point where they tend to rock the chair back on its pivots.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the 12th
May 1879.
[5
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent. IMPROVED COMBINED CHAIR AND TREADLE MECHANISM FOR
OPERATING SEWING AND OTHER MACHINES." A communication from abroad by
Joseph Boykin Underwood, of Fayetteville, Cumberland County, State of North
Carolina, United Sates of America, and John Dawson Smith, also of the United
States of America.
The object of this Invention is to reduce the muscular force exerted in driving
a sewing or other machine operated by a treadle, and to transfer the strain from
the muscles of the abdomen and other parts, which are injuriously affected thereby,
to other muscles which are better able to exert the power and withstand the
fatigue, thus confining the work to the lower part of the legs, and converting a
laborious and injurious operation into one of healthful exercise. The Invention
consists in so pivoting the chair and arranging it upon springs that it shall have
a compound vibratory motion, which adapts it to the movement of the operator,
and in utilising this movement by connecting with the chair a pendant lever frame
projecting from and rigidly attached to the chair, which frame converts the move-
ment of the chair into a reciprocating movement of the treadle through a con-
necting rod, and operates in conjunction with the natural foot movement upon the
treadle, as herein-after more fully described.
In order that the Invention may be more readily understood I have illustrated
it in the annexed Drawings, in which Figure 1 is a side elevation of the chair
applied to the framework of a sewing machine. Figure 2 shows in perspective a
modification of the Invention, with means for adjusting the chair vertically;
Figure 3 is a detail of the chair frame, showing another arrangement for adjusting
the chair vertically; Figure 4 is a detail of the saddle plate.
In the Drawing, A represents the frame; B, the treadle rod; C, the treadle;
D, the connecting rod; and E, the crank shaft of an ordinary form of sewing
machine to which this Invention is shown applied; F is the chair; and G, G, are base
bars, to which the hind legs of the chair are pivoted at a. These base bars G are
extended forwards beneath the treadle rod and provided with notches b to receive
the treadle rod and hold the chair in the desired proximity to the treadle. Beneath
the front legs of the chair are placed springs c, c, which permit the chair to rock on
its pivots a. The chair seat is also pivoted at d to the upper portion of the leg
frames, which gives to the seat of the operator a second point of oscillation. Pro-
jecting downwardly from the chair seat and rigidly connected therewith is a stiff
lever arm or frame H, the lower end of which descends to the level of the treadle.
I is a horizontal connecting rod-jointed adjustably to the lower end of the lever
frame by means of holes and a bolt e, and jointed at its forward end to a short arm g
projecting from the lower side of the treadle. In adapting this connection rod I, for
easy attachment to the treadles of various machines, I employ a saddle plate J,
separately represented in Figure 4, consisting of a plate, arched at f to pass around
the treadle rod, and provided at opposite sides of said arched portion with flat
bearing faces perforated with numerous holes to permit the saddle to be bolted to
the underside of the treadle. The numerous perforations in this saddle plate and
the open character of most treadles permits a binding place for a bolt to be easily
found.
The operator being seated in the chair, and the point or front end of the treadle
being elevated as shown, the operation of the devices would be as follows:-When
seated in the chair the centre of gravity of the operator is in the rear of the seat
pivots d, and the chair seat by its lever connections with the arm g on the bottom
of the saddle transmits its lifting force to the front side of the treadle, thus lifting

page_text: up the toe of the foot. It will thus be seen that no muscular effort whatever is
required to depress the heel of the treadle. When the operator presses with the toe
upon the treadle, this pressure has a tendency to depress the outer end or toe of the
treadle. At the same time also this muscular exertion throws the weight of the body
upon the thighs and shifts the centre of gravity to the front of the pivots d, causing a
compression of the springs, a rocking forward of the chair upon its leg pivots a, and
also a rocking forward of the seat upon its pivots d. This action causes the lower
end of the lever frame H and the connecting rod I to be drawn back, which tends
in conjunction with the toe pressure upon the treadle to bring the toe of the
treadle down. In depressing the heel of the treadle the weight of the body is again
shifted to the rear of the pivots d, the chair moves backward on its pivots d and a,
and the lower end of the lever frame H. in moving forward acts on the treadle in
harmony with the downward movement of the heel portion. It will thus be seen
that the chair moves in accordance with the natural and easy movement of the
lower part of the body in operating the treadle, and not only automatically adjusts
itself to the motion but co-operates to drive the machine by its own movement.
The chair is also so constructed that the great weight and powerful leverage of the
body is kept in nice balance, so that the machine runs not only easier but more
uniformly and without jerks. It will also be seen that the legs of the operator are
not lifted up and down at an expense of muscular power from the seat of the chair,
as is the case in driving the treadle when the chair is rigid and stationary, but the
chair follows and supports the legs with an easy rocking movement, which reduces
the strain upon the abdominal muscles and distributes it throughout the muscles of
the legs. While the foregoing advantages are secured the motion of the chair is
not sufficient to effect the position of the upper portion of the body at the table, a
very slight movement of the seat of the chair being sufficient when multiplied by
the lever frame beneath to produce the desired effect.
In order to make the seat of the chair adjustable as to height for different
operators the chair leg frames may each be provided with a vertical groove or
guide h, see Figure 3, in which a sliding and slotted bar i may be adjustably
secured by a bolt passing through a slot and a hole in the chair frame, the chair
seat having its pivots d at the top end of this slotted and adjustable bar i.
Another means of adjustment, shown in Figure 2, may be used, in which the
lever frame H is rigidly attached to a cross bar j pivoted at d to the top ends of
the chair leg frames, and the scat of the chair is provided with an elevating screw
stem, which turns in a female screw in the said cross bar. The springs of the chair
instead of being placed beneath the front legs, as shown, may be placed at any
point where they would tend to rock the chair back on its pivots a.
Having described the nature of the Invention, and the manner of performing the
same, I declare that what I claim as the Invention to be protected by the herein-
before in part recited Letters Patent is,-
1st. A chair having a compound rocking movement connected to and combined
with the treadle of a sewing machine or other mechanism for the purpose of
utilising the movement of the body to assist in driving the treadle.
2nd. A rocking chair having the seat pivoted to its legs, its front legs held up
by springs, and provided with a connection for the treadle of a machine, sub-
stantially as described.
3rd. A chair arranged to rock on its hind legs and having a second set of pivots
for the seat combined with the treadle, a connecting rod, and a frame or projection
rigidly attached to the chair seat and connected with said treadle by the connecting
rod, substantially as described.
4th. The base bars G, G, having notches b to receive the treadle rod, in com-
bination with the chair and sewing machine, as described.
5th. The saddle plate J, having in the middle an arch with pendant projection g,
in combination with the treadle and a connecting rod for operating the same, as
described.

page_text: 6th. The chair seat pivoted at d to a rocking frame and made vertically adjust-
able, substantially as described.
7th. The chair seat pivoted at d, and having a pendant frame or projection in
combination with the frame pivoted at its rear upon its legs and sustained in front
upon springs c, c, together with the connecting rod I and the treadle C, sub-
stantially as and for the purpose described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Ninth day of May, in the year of our Lord One
thousand eight hundred and seventy nine.
OT TEZ
A. M. CLARK. (L.)