IMPROVEMENTS IN MACHINES FOR CONVERTING RECIPROCATING MOTION INTO ROTARY MOTION
Year: 1881

page_text: LETTERS PATENT to Edgar Edmonds, of the Firm of Robertson, Brooman,
and Company, of 166, Fleet Street, in the City of London, Patent Agents,
for an Invention of "IMPROVEMENTS IN MACHINES FOR CONVERTING
RECIPROCATING MOTION INTO ROTARY MOTION." A communication from
abroad by Frederic Booth Nichols and Cathcart Thomson, both of the
City of Halifax, in the County of Halifax and Province of Nova Scotia.
PROVISIONAL SPECIFICATION left by the said Edgar Edmonds at the
Office of the Commissioners of Patents 'on the 3rd March 1881.
EDGAR EDMONDS, of the Firm of Robertson, Brooman, and Company, of
166, Fleet Street, in the City of London, Patent Agents. "IMPROVEMENTS IN
MACHINES FOR CONVERTING RECIPROCATING MOTION INTO ROTARY MOTION."
(A communication from abroad by Frederic Booth Nichols and Cathcart Thomson,
both of the City of Halifax, in the County of Halifax and Province of Nova
Scotia.)
This Invention relates to certain new and useful improvements in machines for
converting reciprocating motion into rotary motion, which improvements are fully
set forth in the following Specification, reference being had to the accompanying
Drawings.
Figure 1 is a top view or plan.
Figure 2 is a section through a, a, Figure 1 showing cog-wheels D, I, rack H, and
guide wheel L.
Figure 3 is a section showing the pawl carrier attached to cog-wheel D, with end
view of pawl in the act of dropping from the cam into the ratchet.
Figure 4 is a section showing the pawl going forward engaged with the
ratchet.
Figure 5 is a section showing the pawl riding back over the cam.
.

page_text: Figure 6 is the pawl with its spring and projection h above the pivot to prevent
its falling away from the cam while passing around on the outside.
The machine consists of a shaft A, Figure 1, turning freely in its bearings in the
frame C, C. This shaft has two ratchet wheels, B, B, securely fastened to it.
Between these ratchet wheels are two cog-wheels D, X, separated by the space E.
Each of these cog-wheels have pieces F, F, fastened to them for the purpose of
pivoting the pawls G, G, in position to perform their functions. These cog-wheels
with their pawl carriers F, F, rotate freely on the shaft A. One of these cog-
wheels D gears with the reciprocating toothed rack H. The other one X runs
clear of the rack H, but gears with one half of the cog-wheel I, the other half
of I gearing with the rack H, and in position not to engage with the teeth of the
cog-wheel D. This intermediate cog-wheel I causes X to rotate in the opposite
direction to the rotation of D, as seen in Figure 1; X moves in the same direction
as the rack, whilst D and I move in the opposite direction to the rack. Thus when
the rack is pushed in the direction of the arrow shown below it, the cog-wheels D, X,
and I, each move in the direction of the arrows annexed to them. On reversing
the direction of the rack the rotation of the cog-wheels will likewise be reversed.
This alternate rotation of the cog-wheels D and X in opposite directions causes the
pawl of the on-going forward to engage in the teeth of the ratchet, whilst the other
pawl slides back free, and by alternating with each other keep up a constant
rotation of the shaft A and fly wheel Y.
The rack H is attached to a piston rod J, which can be worked by steam or
other power; K represents the stuffing box of the engine cylinder. The rack is
kept up in gear with the cog-wheels D and I by means of a smooth faced wheel L,
Figure 2. Both L and I rotate freely on their axis.
In order to prevent the pawls from clicking over the ratchets in their backward
movement, the following device is adopted-Two discs holding the ring shaped
cams M, M, are fastened to the inside of the frame, each facing the ratchet wheels.
The ends of these rings from 6 to c, and b¹ to c¹, Figures 4 and 5, are free from the
discs, and are formed into springs. bending inward the ends c, c, e, e, Figure 1,
projecting over and resting on the edge of the discs, which are here made smaller
in diameter; this prevents the springs from falling too far. A space is left between
the ends of the springs that form a part of the cams to allow the springs on the
pawls to pass up and down.
The pawls each have a spring f, Figures 1 and 6, on the outside, fastened near
the point, the upper end being free; these serve as lugs to lift the pawls and carry
them around on the outside of the cam in going backward, keeping them clear of
the ratchets till an entire rotation is made, when they drop down through the space
between c and c'; then on going forward the point of the spring on the pawl
passes under the cam spring, and, pressing against the inside of the cam, forces the
pawl down into the teeth of the ratchet, causing it to rotate the shaft, the cam
spring and pawl spring yielding as it passes in and out.
Instead of the ends of the cams terminating with springs, pieces can be hinged
at band b¹ that will rise and fall to allow the pawl spring to pass in and out.
The movement of the rack should just correspond in length with the circum-
ference of the cog-wheels D, X, so that one entire revolution is made at each stroke
of the rack whether going forward or backward. If the movement is stopped
at the end of the stroke either way, the pawls will both be at the top between c
and c¹, when if desirable to change the direction of the rotation it can be imme-
diately done by turning both pawls over in the opposite direction, and again
applying the power to the rack, the arrangement of attaching the springs to the
pawls allowing them to work equally well in either direction.
By means of the mechanism above described, the power of the piston is com-
municated with equal force to produce rotation of the shaft at all parts of its
stroke, consequently the engine can be started as readily when the piston is at
the end of its stroke as at any other point, or, in other words, never gets
centre."
56
on the

page_text: It will be evident that the reciprocating movement of a toothed rack made in a
segment of a circle, and oscillating on a fixed pivot at its radius, can be substituted
for the piston movement of a straight rack kept up in place with a guide roller,
and that the common pawl and ratchet can be used where the rotation is only
required to be in one direction, the arrangement of pawls and cams specified being
intended for reciprocating piston engines only; but where the rotary mechanism is
actuated by foot power, the oscillating rack and common pawl and ratchet will be
found the most convenient method of applying it.
It will likewise be evident that smooth faced wheels and racks, working on the
principle of friction gearing by close contact, can be substituted for toothed wheels
and racks where the power required is not great.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edgar Edmonds in the Great Seal Patent Office on the 2nd
September 1881.
EDGAR EDMONDS, of the Firm of Robertson, Brooman, and Company, of
166, Fleet Street, in the City of London, Patent Agents. "IMPROVEMENTS IN
MACHINES FOR CONVERTING RECIPROCATING MOTION INTO ROTARY MOTION."
(A communication from abroad by Frederic Booth Nichols and Cathcart Thomson,
both of the City of Halifax, in the County of Halifax and Province of Nova
Scotia.)
This Invention relates to certain new and useful improvements in machines for
converting reciprocating motion into rotary motion, which improvements are fully
set forth in the following Specification, reference being had to the accompanying
Drawings.
Figure 1 is a top view or plan.
Figure 2 is a section through a, a, Figure 1, showing cog wheels D, I, rack H,
and guide wheel L.
Figure 3 is a section showing the pawl carrier attached to cog wheel D, with
end view of pawl in the act of dropping from the cam into the ratchet.
Figure 4 is a section showing the pawl going forward engaged with the ratchet.
Figure 5 is a section showing the pawl riding back over the cam.
Figure 6 is the pawl with its spring, and the projection h above the pivot to
prevent its falling away from the cam while passing around on the outside.
The machine consists of a shaft A, Figure 1, turning freely in its bearings in the
frame C, C; this shaft has two ratchet wheels B, B, securely fastened to it; between
these ratchet wheels are two cog wheels D, X, separated by the space E; each of
these cog wheels have pieces F, F, fastened to them for the purpose of pivoting
the pawls G, G, in position to perform their functions; these cog wheels with their
pawl carriers F, F, rotate freely on the shaft A; one of these cog wheels D gears
with the reciprocating toothed rack H, the other one X runs clear of the rack H
but gears with one half of the cog wheel I, the other half of I gearing with the
rack H, and in position not to engage with the teeth of the cog wheel D; this
intermediate cog wheel I causes ✗ to rotate in the opposite direction to the rotation
of D, as seen in Figure 1; X moves in the same direction as the rack, whilst D
and I move in the opposite direction to the rack; thus when the rack is pushed in
the direction of the arrow, shown below it, the cog wheels D, X, and I, each move
in the direction of the arrows annexed to them; on reversing the direction of the
rack the rotation of the cog wheels will likewise be reversed.
This alternate rotation of the cog wheels D and X in opposite directions causes
the pawl of the on going forward to engage in the teeth of the ratchet, whilst the
other pawl slides back free, and by alternating with each other keep up a constant
rotation of the shaft A and fly wheel Y.
The rack H is attached to a piston rod J, which can be worked by steam or
other power; K represents the stuffing box of the engine cylinder; the rack is
kept up in gear with the cog wheels D and I by means of a smooth faced wheel L,
Figure 2; both L and I rotate freely on their axis.
In order to prevent the pawls from clicking over the ratchets in their backward
movement the following device is adopted:-Two discs holding the ring shaped
4

page_text: cams M, M, are fastened to the inside of the frame, each facing the ratchet wheels;
the ends of these rings, from 6 to c and b¹ to c¹, Figures 4 and 5, are free from the
discs, and are formed into springs bending inward, the ends e, e, e, e, Figure 1,
projecting over and resting on the edge of the discs, which are here made smaller
in diameter; this prevents the springs from falling too far; a space is left between
the ends of the springs that form a part of the cams to allow the springs on the
pawls to pass up and down. The pawls each have a spring f, Figures 1 and 6, on
the outside, fastened near the point, the upper end being free; these serve as lugs
to lift the pawls and carry them around on the outside of the cam in going back-
ward, keeping them clear of the ratchets till an entire rotation is made, when they
drop down through the space between c and c¹, then on going forward the point of
the spring on the pawl passes under the cam spring, and pressing against the inside
of the cam forces the pawl down into the teeth of the ratchet, causing it to rotate
the shaft, the cam spring and pawl spring yielding as it passes in and out.
Instead of the ends of the cams terminating with springs, pieces can be hinged at b
and 6 that will rise and fall to allow the pawl spring to pass in and out.
The movement of the rack should just correspond in length with the circum-
ference of the cog wheels D, X, so that one entire revolution is made at each stroke
of the rack whether going forward or backward. If the movement is stopped at
the end of the stroke either way the pawls will both be at the top, between c and c¹,
when if desirable to change the direction of the rotation it can be immediately
done by turning both pawls over in the opposite direction and again applying the
power to the rack, this arrangement of attaching the springs to the pawls allowing
them to work equally well in either direction.
By means of the mechanism above described, which is styled a "rotator," the
power of the piston is communicated with equal force to produce rotation of the
shaft at all parts of its stroke, consequently the engine can be started as readily
when the piston is at the end of its stroke as at any other point, or in other words
never gets on the centre.
It will be evident that the reciprocating movement of a toothed rack made in a
segment of a circle and oscillating on a fixed pivot at its radius can be substituted
for the piston movement of a straight rack kept up in place with a guide roller,
and that the common pawl and ratchet can be used where the rotation is only
required to be in one direction, the arrangement of pawls and cams specified being
intended for reciprocating piston engines only, but where the rotary mechanism is
actuated by foot power the oscillating rack and common pawl and ratchet will be
found the most convenient method of applying it.
It will likewise be evident that smooth faced wheels and racks working on the
principal of friction gearing by close contact can be substituted for toothed wheels
and racks where the power required is not great.
And having now described the nature of the said Invention, and in what manner
the same is to be performed, I declare that I claim on behalf of my foreign
correspondents,―
First. The toothed wheels D and X with their pawl carriers and pawls in
combination with the reciprocating toothed rack H or its equivalent, and the
intermediate toothed wheel I, substantially as shown for the purpose specified.
Secondly. The combination of a reciprocating piston rod or its equivalent with a
toothed rack and two toothed wheels carrying pawls that work alternately into
ratchets, one of the said wheels X being connected with the rack by the
intermediate toothed wheel I, substantially in the manner and for the purpose
described.
Thirdly. The springs f attached to the pawls, substantially as shown for the
purpose specified.
Fourthly. The pawl springs f working in combination with the ring shaped
cams M, M, and cam springs b, b', or their equivalents, substantially in the manner
and for the purpose specified.

page_text: Fifthly. The substitution of smooth faced wheels and racks or friction gearing
for toothed wheels and racks in the combination herein specified.
In witness whereof, I, the said Edgar Edmonds, have hereunto set my hand
and seal, this Second day of September, One thousand eight hundred and
'eighty one.
:
EDGAR EDMONDS. (L.S.)