IMPROVEMENTS IN VOLUTE SPRING MOTORS
Year: 1876

page_text: LETTERS PATENT to Roland Rhett, of the City of Baltimore, and State of
Maryland, one of the United States of America, Manufacturer, for the
Invention of "IMPROVEMENTS IN VOLUTE SPRING MOTORS."
Sealed the 19th June 1877, in pursuance of an order of the Lord Chancellor, and
dated the 12th December 1876.
PROVISIONAL SPECIFICATION left by the said Roland Rhett at the Office
of the Commissioners of Patents on the 12th December 1876.
ROLAND RHETT, of the City of Baltimore, and State of Maryland, one of the
United States of America, Manufacturer. IMPROVEMENTS IN VOLUTE SPRING
MOTORS."
"
My Invention relates, first, to a series of volute springs which are attached directly
to a central winding spindle and adapted to coil and uncoil in the same plane, the
said springs being arranged within the cage in which they are confined to occupy a
space, the width of which is equal to that of a single spring, as and for purposes
herein-after described.
My Invention relates, secondly, to the manner of connecting the outer ends of the
said springs to the cage containing them, whereby they exert a variable tension or
strain upon the said cage or the parts of the moving mechanism to which they are
directly attached, and to a certain combination of gearing, whereby the winding
stem is arranged in such manner with reference to the said springs as to admit of
the said winding stem being revolved by a key or equivalent device to coil or
compress the said springs while the same are uncoiling and performing useful
work.
My Invention relates, thirdly, to a stop or check designed to limit the tension or
strain upon the said springs in the winding of the same, and to prevent a reverse or
counter coiling of the springs when the same are sufficiently unwound to be inert
or destitute of power to communicate motion to connecting mechanism.
The springs are attached at their inner ends to the central winding shaft or
spindle. The outer ends of the springs are connected to the cage by means of pins
in such manner as to allow of a radial movement of the outer ends of the springs in
the coiling and uncoiling of the same, for purposes herein-after described.

page_text: The slots in which the pins move may be either curved or straight, as will be
found in practice best adapted, to admit of a free and regular movement of the said
pins towards and from the winding shaft. The cage is rigidly connected to the
main spur wheel which revolves upon and independently of the central winding
shaft, and from which movement is transmitted by means of a system of gearing or
by belts to the driving shaft provided with a pulley.
In using a series of springs attached to the cage at points equidistant from cach
other the said springs are made to occupy the same relative positions with reference
to the central winding shaft, consequently the tendency of the springs to be drawn
toward one side of the cage in the winding operation is prevented, the strain being
equal in all directions.
Another advantage in using a series of springs which coil and uncoil in the same
plane is that the increase in their number does not affect the width of the cage or
require any additional number of cages, thereby adapting the motor for use in
limited spaces or where increased weight would be objectionable. The said springs
are coiled or wound by revolving the central winding shaft through the medium of
the winding stem, which is connected by means of gearing, therewith. By the
radial movement of the outer ends of the springs above described the motion of the
said springs, when wound or compressed and in a condition to revolve the driving
shaft at its maximum velocity, is communicated to the cage at a point near to the
shaft upon which the said springs are coiled. As the springs unwind the radial
distance of the outer ends thereof from the shaft is gradually increased, and the
effective leverage of the springs augmented, this compensating for their reduced
elastic force.
It will be understood that the relative, proportions of the various parts of this
Invention are designed to be such as to cause a nearly uniform movement of the
pulley on the driving shaft. An ordinary brake is used to govern the speed of the
said pulley. The aforesaid stop consists of a threaded sleeve screwed within the
main spur wheel, and secured to the winding shaft by means of a feather or other
device, whereby a combined rotary motion of the said shaft and sleeve and an inde-
pendent longitudinal movement of the latter are obtained.
.
The longitudinal movement of the stop is limited in one direction by a collar
which comes into contact with the face of the spur wheel, and in the other direction
by a suitable collar on the shaft, or by one of the gear wheels or the frame. A
suitable frame is provided as a support for the above described mechanism. This
motor is applicable to all purposes for which spring motors are usually employed
by merely modifying the character of the frame and other minor parts.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Roland Rhett in the Great Seal Patent Office on the 19th June
1877.
ROLAND RHETT, of the City of Baltimore, and State of Maryland, one of the
United States of America, Manufacturer. "IMPROVEMENTS IN VOLUTE SPRING
MOTORS."
My Invention relates, first, to a series of volute springs which are attached
directly to a central winding spindle, and adapted to coil and uncoil at the same
plane, the said springs being arranged within the cage in which they are confined
to occupy a space, the width of which is equal to that of a single spring, as and for
purposes herein-after fully described.
My Invention relates, secondly, to the manner of connecting the outer ends of
the said springs to the cage containing them, whereby they exert a variable tension
or strain upon the said cage or upon the parts of the moving mechanisin to which
they are directly attached, and to a certain combination of gearing connecting the

page_text: springs with the winding stem, whereby the said winding stem may be revolved by
a key or equivalent device to coil or compress the said springs while the same aro
uncoiling and performing useful work.
My Invention relates, thirdly, to a stop or check designed to limit the tension or
strain placed upon the said springs in the winding of the same, and to prevent a
reverse or counter coiling of springs when the same are sufficiently unwound to be
inert or destitute of power to communicate motion to connecting mechanism.
In the accompanying Drawing,
Figure 1 is an exterior side elevation of my improved motor; and Figure 2, a
reversed view of the same.
Figure 3 is an exterior end elevation of the Invention.
Figures 4, 5, and 6 are views of parts of the Invention, some of which views are
on an enlarged scale.
Similar letters of reference indicate similar parts of the Invention in all tho
Figures.
A is the cage; and B, B, are the springs attached at their inner ends to the
central winding shaft or spindle a. The outer ends of the springs B are connected
to the cage A by means of pins b in such manner as to allow of a radial movement
of the outer ends of the springs in the coiling and uncoiling of the same, for purposes
herein-after described.
The slots in which the pins b move may be either curved or straight, as will be
found in practice best adapted, to admit of a free and regular movement of the said
pins towards and from the winding shaft. The cage A is rigidly connected to the
main spur wheel C which revolves upon and independently of the central winding
shaft a, and from which wheel movement is transmitted by means of a system of
gearing or by belts and the like to the driving shaft D provided with a pulley.
In using a series of springs attached to the cage at points equidistant from each
other, as shown, the said springs are made to occupy the same relative positions
with reference to the central winding shaft a, consequently the tendency of the
springs to be drawn toward one side of the cage in the winding operation is pre-
vented, the strain being equal in all directions.
Another advantage in using a series of springs which coil and uncoil in the same
plane consists in that the increase in their number does not affect the width of the
cage or require any additional number of cages, thereby adapting the motor for use
in limited places or where increased weight would be objectionable. The springs B
are coiled or wound by revolving the central winding shaft a through the medium
of the winding stem c, which stem is connected by means of gearing therewith. By
the radial movement of the outer ends of the springs, as described, the motion of
the said springs when wound or compressed and in a condition to revolve the
driving shaft at its maximum velocity is communicated to the cage at a point near
to the shaft a upon which the said springs are coiled. As the springs unwind, the
radial distance of the outer ends thereof from the shaft a is gradually increased, and
the effective leverage of the springs augmented, thus compensating for their reduced
clastic force.
It will be understood that the relative proportions of the various parts of the
Invention aro designed to be such as to cause a nearly uniform movement of the
pulley on the driving shaft D. An ordinary brake is used to govern the speed of
the said pulley. The stop before referred to consists of a threaded sleeve E screwed
within the main spur wheel C, and secured to the winding shaft a by means of a
feather or other device, whereby a combined rotary motion of the said shaft and
sleeve and an independent longitudinal movement of the latter are obtained.
The longitudinal movement of the stop is limited in one direction by a collar
which comes into contact with the face of the spur wheel C, and in the other
direction by a suitable collar on the shaft a, or by one of the gear wheels or the
frame. A suitable frame is provided as a support for the above described
mechanism, and it is shown in the Drawing as adapting the motor specially for
attachment to sewing machines. The motor is however applicable to all purposes

page_text: for which spring motors are usually employed by merely modifying the character of
the frame and other minor parts.
Having thus described and ascertained the nature of my said Invention, I desire
it to be understood that I claim as secured to me under the above in part recited
Letters Patent, and for the purpose set forth,-
1st. In a spring motor, a series of volute springs, the outer ends of which are
attached to the cage in which they are confined at points equidistant or nearly
equidistant from each other, and their inner ends connected to the central winding
shaft, the said springs being arranged to move in the same plane in the coiling and
uncoiling operations.
2d. The cage A having the radial slots, as described, in combination with a series
of volute springs, the outer ends of which are adapted to have a free radial move-
ment in the coiling and uncoiling of the same.
3d. The shaft a, springs B, cage A, and winding stem c combined with the
gearing connecting the said winding stem with the shaft a.
4th. The springs B, the outer ends of which have a free radial movement, as
described, and their inner ends secured to the shaft a combined in a suitable frame
with said shaft a, cage A, and main spur wheel C.
5th. As a means of preventing injurious strain being transmitted to a volute
spring or to a system or series of volute springs in the coiling or in the uncoiling of
the same, a threaded stop having a limited longitudinal movement on the central
winding shaft and within a disc forming a part of the spring cage, or within a
wheel or other device rigidly connected thereto, and a rotary screw motion within
the said disc and the like, and independently thereof.
In witness whereof, I, the said Roland Rhett, have hereunto set my hand and
seal. this Twenty-second day of May, A.D. 1877.
Witnesses,
WILLIAM THOMPSON HOWARD,
Patent Agent,
18, Second St.,
Baltimore,
Maryland.
WOODRUFF WATSON WHARTON,
Clerk,
18, Second St.,
ROLAND RHETT. (L.S.)
Baltimore,
Maryland.