Improvements in Clutches.
Year: 1888

page_text: Date of Application, 20th Oct., 1888
Complete Specification Left, 22nd July, 1889-Accepted, 7th Sept., 1889
PROVISIONAL SPECIFICATION.
Improvements in Clutches.
1, CHARLES LESTER HART, with the E. W. Bliss Company, No. 17 Adams Street,
Brooklyn, in the State of New York, United States of America, Machinist, do
hereby declare the nature of this invention to be as follows:-
--
This invention relates to that class of clutches wherein a continuously revolving
driving part is coupled at will to a normally-stationary driven part and carries the
latter with it for one revolution, or for any number of revolutions, until the clutch
is released, whereupon the driven part is stopped, usually at the same point in the
revolution at which it stood at starting. Such clutches, which are generally known
as "one-revolution clutches," are most frequently used in connection with power
presses where a plunger or movable die stands normally at the top of its stroke and
is driven down upon the bed or fixed die and lifted again to its normal position
whenever the operator manipulates a treadle or operating lever. In such presses the
driving part is usually a wheel or pulley to which continuous rotation is imparted by
a belt or otherwise, and the driven part is a shafs on which said wheel turns freely
and which shaft is formed with a crank or eccentric for imparting motion to the
plunger.
My invention although designed especially for use in power presses of this class, is
nevertheless adapted to a great variety of other uses in connection with driving
shafts and machinery.
My improved clutch is of that class wherein the driving and driven parts are pro-
vided the one with a ratchet notch and the other with a driving pawl the free end of
which is pressed out into engagement with said notch, so that when the pawl is
released the driving part engages the driven part through the medium of the pawl
and carries the latter around with it. The pawl is retracted by mechanism operated
at will to free the pawl and engage the clutch. According to my invention this
mechanism consists of a stationary cam-stop having a cam face in position to be
encountered by the pawl in its rotation and so shaped as to move the pawl out of
engagement with the notch, so that the clutch is disconnected; the stop being mounted
in such manner that it may be displaced at will out of the path of the pawl so that
the latter is released and permitted to engage the clutch. The cam-face of the
stop is so shaped that if the driven part fails to come immediately to rest upon the
disengagement of the clutch its motion will be arrested by the contact of the pawl
with an abrupt portion of the cam-face. The portion of the pawl with which the cam-
stop engages projects beyond the plane of the ratchet notch, or in other words,
beyond the plane of an annular recess in the driving or driven part in which the pawl
is housed.
In order to prevent the rotation of the driven part more rapidly than the driving
part, I provide also another pawl and notch which are so arranged relatively as to
engage in the opposite rotative direction from that in which the driving pawl and its
notch engage. The notch for this retarding pawl is arranged in position to be engaged
by it when the notch for the driving pawl is engaged, so that the driving and driven
parts are connected together through the medium of two pawls working in opposite
directions, the one forcing the driven part to turn as fast as the driving part and the
other preventing the driven part from turning any faster than the driving part. This
retarding pawl is formed with a laterally projecting portion, which in the position of
rest of the driven part is engaged by a stationary throw-off cam which holds the
pawl retracted in order that it shall not make a clicking noise during the free
revolution of the driving part by dropping in and out of the notches therein at each
revolution

page_text: In the accompanying drawings my invention is shown as adapted for use as the
driving clutch of a power press.
Figure 1 is a perspective view of a power press having my clutch applied
thereto.
Fig. 2 is a view of the clutch on a larger scale, being a sectional elevation cut on a
line with the side of the press frame as denoted by the line 2-2 in Fig. 3, and
looking away from the press. frame.
Fig. 3 is a vertical mid-section cut on the line 3-3 in Fig. 2, and looking from
the front of the machine.
Fig. 4 is a vertical transverse section cut on the line 4-4 in Fig. 3 and looking
toward the press frame. The driving wheel is wholly removed in this figure.
Fig. 5 is a vertical transverse section cut in the plane of the line 5-5 in Fig. 3
and looking away from the press frame.
Fig. 6 is a vertical transverse section cut in the plane of the line 6-6 in Fig. 3
and looking away from the press frame.
Fig. 7 is a sectional view answering to Fig. 6 but showing the parts in a
slightly different position.
Figs. 8 and 9 are perspective views of the driving and retarding pawls
removed.
Figs. 2, 6 and 7, show the machine while the driven part or crank shaft is
at rest while Figs. 4, and 5 show the clutch engaged and the driven part or
shaft carried to half a revolution from its starting point.
Let A designate the frame of the power press, B the driving wheel thereof, and C
the crank shaft which operates the plunger of the press and which projects through
the hub of the driving wheel and remains normally stationary while the wheel,
which is continuously driven by a belt, revolves freely upon it.
The wheel or pulley B is the driving part and the shaft is the driven
part.
In the side of the hub 13 of the driving wheel there is formed a circular
recess 14, in the defining wall of which are two diametrically opposite ratchet
driving notches and also two diametrically opposite ratchet retarding notches d d.
"The shaft C is formed within the recess 14 with a collar 18 and a block 19 pro-
jecting to one side of the shaft. A driving pawl a and a retarding pawl care
pivoted to the shaft by being formed with cylindrical butt ends 22, which enter
circular seats or recesses 21, 21 in the opposite sides of the block 19. The pawls a
and care pressed outwardly by springs 26 and 27. The lateral displacement of the
pawls is prevented by pins 25 (Fig. 4), which are driven or screwed radially through
the block 19 so that they intersect tangentially the sockets 21, 21, and enter
grooves 12, 12 formed in the butt ends of the pawls, as shown in Figs. 4, 8
and 9.
The preferred construction of the ratchet notches bd is that shown, circular
recesses 15, 15 being bored out at diametrically opposite sides of the hub 13, and
wear plugs or blocks 16, 16 being inserted fast in the recesses.
The bearing
faces 17, 17 of the plugs 16 are made slightly concave, being circular arcs con-
centric with the pivotal axes of the pawls a and c when the latter are in engagement
with the notches bd, as shown in Figs. 4 and 5, and the ends of the pawls are also
rounded in circular arcs from the same axial centres. Essentially the wheel B
need be provided with only one notch 6 and one notch d, but preferably two notches
of each kind are provided, as shown, so that the same wear plug 16 serves as the abut-
ment face for both notches. The number of notches may be still further multiplied if
desired.
Normally, the driving wheel B is revolving in the direction of the arrow in the
several figures, and the shaft is stationary, its pawls a and c being retracted or
drawn inwardly in order that their free ends may not engage with the ratchet
notches. The driving pawl a is held retracted by a cam-stop E, which is formed
with a cam-face 36, which is normally arranged in the path of a projection 42
formed on the pawl a, and extending outside the recess 14, as shown in Fig. 3.
:

page_text: In order to provide means for engaging the clutch the, cam-stop E is made
movable at will in order to carry it out of the path of the projection 42, so that
the pawl a may be freed and be pressed outwardly by its spring. This movement of
the cam-stop may be in any suitable direction in order to carry it away from the
projection 42, but it is preferably in a direction away from the wheel B, in which
case it must move sufficiently far to bring it beyond the end of the projection 42.
To accomplish this movement the stop E is preferably made in the form of a hinged
leaf pivoted on a horizontal axis at its lower side, as shown. In the construction
shown the hinged leaf is formed in one piece with its pintle 35, on the projecting
end of which is fixed a crank arm 38, which is connected by a rod 40, to the usual
operating pedal 39, which is drawn up by a spring 41.
When the treadle is depressed the stop E is tilted in the manner shown in
dotted lines in Fig. 3, thereby freeing the projection 42 and permitting the pawl a
to fly outwardly, so that its free end 23 rides against the outer wall of the recess 14,
as shown in Fig. 7. When, in the rotation of the wheel B, the next approaching
ratchet notch bencounters the pawl, the latter enters this notch and its end abuts
against the working face 17 of the wear plug 16, whereupon this plug drives the
pawl before it and through the medium of the pawl it drives the shaft around with
the wheel. If, as is usually the case, the treadle he released before one revolution is
completed, the cam-stop E moves back into the path of the projection 42, and at the
end of the revolution the projection rides upon the cam-face 36 and lifts the pawl
out of the notch , thereby disengaging the clutch. The cam-face 36 is of such con-
tour that the rise from the forward edge (which is first encountered by the
projection 42) is at first slight, but toward the rear edge the rise becomes more
abrupt, forming a considerable cam projection 37. The gradually rising cam-face 36
first acts to lift the pawl with a comparatively slow movement until it is lifted quite
free from the notch. If the momentum of the shaft tends to carry it beyond its
normal position of rest, the projection 42 will be brought against the abrupt rise 37
of the cam-face, which will still further lift the pawl until it is brought into firm
abutment with the shoulder 49 on the collar 18, so that by this abutment the pawl
becomes essentially a fixed arm or projection from the shaft which, tending to rotate
concentrically around the axis of the shaft, is resisted by the abrupt cam projection 37,
whereby the further rotation of the shaft is prevented.
It is important to provide the cam-stop E with an adjustable and at the same time
a firm and unyielding supporting bearing. The pintle 35 is carried in a cylindrically
grooved bearing in a block 32, which block is socketed in the lower part of a case.30,
which is bolted to the frame A of the press. The block 32 is mounted to slido
vertically in its socket in the case 30 and is adjusted up or down by a screw 45,
and when in the proper position is fastened by holts 33, 33.
When the clutch is engaged and the driving pawl becomes seated in the ratchet
notch b the opposite retarding notch d is in a position coincident with the 'free end of
the retarding pawl c, and is entered by the latter, as shown in Figs. 4 and 5, so that
the shaft is prevented from revolving faster than the driving wheel
In order to prevent the clicking noise and consequent wear which would be
occasioned by the free end of the retarding pawl dropping into the successive ratchet
notches during the free rotation of the driving wheel, I provide a stationary throw-
off cam 44 which has a cam-face formed to gradually approach the center of rotation
and arranged in such position that when the retarding pawl in the course of its
rotation nears the end of the revolution, a lateral projection 43 formed upon its side
shall encounter this inclined cam-face and be displaced inwardly by it, whereby the
pawl c is retracted out of engagement with the ratchet notches, as best shown in
Fig. 6.
The cam-block 44 does not interfere with the driving pawl a for the reason that it
is arranged in a transverse plane beyond the end of the projection 42, as is clearly
shown in Fig. 3. On the other hand the cam-stop E does not interfere with the
retarding pawl for the reason that the projection 43, being made narrower than the

page_text: projection 42, does not extend far enough from the center to touch the cam-stop E in
its revolution.
If it be desired that the shaft shall turn more than one revolution, the operator will
hold the treadle depressed, so that the driving pawl in passing the cam-stop E will not
be engaged and retracted thereby.
It is obvious that the construction of my clutch might be changed in many ways
and the parts might be differently arranged, .without departing from the essential
features of my invention. For example the pawls, instead of being pivoted to the
inner of the two concentric parts and engaging notches in the outer part, might be
pivoted to the outer part and engage notches in the inner part. Also the pawls
instead of being borne by the driven part which is normally at rest, might be borne
by the driving part so as to be normally in revolution with it.
These modifications of my clutch are embodied in the construction shown in Fig. 10,
which is a vertical section answering to Fig. 6. The pawls a and c are here mounted
in recesses formed in the wheel hub instead of being connected to the shaft, and the
notches and d are formed in the block 19, which is fixed to the shaft. The pawls
are formed with toes 42%, and 43*, respectively, which take the place of the projec-
tions 42 and 43 in the construction first described, the toe 42ª being narrower than
the toe 43 in order that it may freely pass in inclined-faced block 50, which acts to
throw the retarding pawl c out of engagement with its notch d. The cam-stop E is
mounted similarly to the construction first described and its cam-face acts upon the
toe 42 in passing to throw its free end out and prevent its engagement with the
abrupt face 9 of its notch b.
I have shown the pawls as being pressed out by springs, but it will be understood
that gravity may be substituted as an equivalent for spring pressure.
Dated this Ninth day of October 1888
CHARLES LESTER HART.
J. C. Mewburn,
169, Fleet Street, London, Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Clutches.
1, CHARLES LESTER HART with the E. W. Bliss Company, No. 17 Adams Street,
Brooklyn in the State of New York, United States of America, Machinist, 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:
23
This Invention relates to that class of clutches wherein a continuously-revolving
driving part is coupled at will to a normally stationary driven part and carries the
latter with it for one revolution, or for any number of revolutions until the
clutch is released, whereupon the driven part is stopped, usually at the same
point in the revolution at which it stood at starting. Such clutches, "which
are generally known as "one revolution clutches, are most frequently used in
connection with power-presses where a plunger or movable die stands normally
at the top of its stroke and is driven down upon the bed or fixed die and
lifted again to its normal position whenever the operator manipulates a treadle
or operating-lever. In such presses the driving part is usually a wheel or pulley to
which continuous rotation is imparted by a belt or otherwise, and the driven part is a
shatt on which said wheel turns freely, and which shaft is formed with a crank or
excentric for imparting motion to the plunger.
My invention although designed especially for use in power-presses of this class, is
nevertheless adapted to a great variety of other uses in connection with driving-shafts
and machinery.
My improved clutch is of that class wherein the driving and driven parts are pro-
vided, the one with a ratchet notch and the other with a driving pawl, the free end of
which is pressed out by a spring into engagement with said notch, so that when the

page_text: my
pawl is released the driving part engages the driven part through the medium of the
pawl and carries the latter around with it. The pawl is retracted by mechanism
operated at will to free the pawl and engage the clutch. According to invention
this mechanism consists of a stationary cam-stop having a cam face in position to be
encountered by the pawl in its rotation and so shaped as to move the pawl out of
engagement with the notch, so that the clutch is disconnected, the stop being mounted
in such manner that it may be displaced at will out of the path of the pawl, so that
the latter is released and permitted to engage the clutch. The cam face of the stop is
so constructed that if the driven part fails to come immediately to rest upon the
disengagement of the clutch its motion will he arrested by the contact of the pawl with
a raised portion of the cam face. The portion of the pawl with which the cam stop
engages projects beyond the plane of the ratchet notch, or, in other words, beyond the
plane of an annular recess in the driving or driven part in which the pawl is housed.
In order to prevent the rotation of the driven part more rapidly than the driving
part, I provide also another pawl and notch, which are so arranged relatively as to
engage in the opposite rotative direction from that in which the driving pawl and its
notch engage. The notch for this retarding pawl is arranged in position to be engaged
by it when the notch for the driving pawl is engaged, so that the driving and driven
parts are connected together through the medium of two pawls working in opposite
directions, the one forcing the driven part to turn as fast as the driving part and the
other preventing the driven part from turning any faster than the driving part. This
retarding pawl is formed with a laterally projecting portion, which in the position of
rest of the driven part is engaged by a stationary throw off cam, which holds the pawl
retracted in order that it shall not make a clicking noise during the free revolution of
the driving part by dropping in and out of the notches therein at each revolution. In
the drawings which accompanied my Provisional Specification and to which I will
refer in this Specification my invention is shown as adapted for use as the driving
clutch of a power press.
Figure 1 is a perspective view of a power press having my clutch applied thereto.
Figure 2 is a view of the clutch on a larger scale, being a sectional elevation cut on
a line with the side of the press frame, as denoted by the line 2, 2 in Fig. 3, and
looking away from the press frame. Fig. 3. is a vertical mid-section cut on the
line 3, 3 in Fig. 2, and looking from the front of the machine. Fig. 4 is a vertical
transverse section cut on the line 4, 4 in Fig. 3, and looking toward the press frame.
The driving wheel is wholly removed in this figure. Fig. 5 is a vertical transverse
section cut in the plane of the line 5, 5 in Fig. 3, and looking away from the press
frame. Fig. 6 is a vertical transverse section cut in the plane of the line 6, 6 in Fig. 3,
and looking away from the press frame. Fig. 7 is a sectional view answering to
Fig. 6, but showing the parts in a slightly different position. Figs. 8 and 9 are
perspective views of the driving and retarding pawis removed; and Fig. 10 is a
vertical section answering to Fig. 6, and showing a modified construction. Figs. 2,.
3, 6, and 7 show the machine while the driven part or crank shaft is at rest, while
Figs. 4 and 5 show the clutch engaged and the driven part or shaft carried to half a
revolution from its starting point.
Let A designate the frame of the power press; B, the driving wheel thereof; and
C, the crank shaft, which operates the plunger of the press, and which projects through
the hub of the driving wheel and remains normally stationary while the wheel, which
is continuously driven by a belt, revolves freely upon it.
.
Io
The wheel or pulley B is the driving part, and the shaft C is the driven part.
the side of the hub 13 of the driving wheel there is formed a circular recess, 14, in the
defining wall of which are two diametrically opposite ratchet driving notches, bb, and
also two diametrically opposite ratchet retarding notches, d d. The shaft C is formed
within the recess 14 with a collar, 18, and a block, 19, made integral with said collar
and projecting to one side of the shaft. The collar may be made integral with the
shaft or welded or otherwise secured thereto. A driving pawl, a, and a retarding
pawl, c, are pivoted to the shaft by being formed with cylindrical butt ends 22, which

page_text: enter circular seats or recesses 21, 21 in the opposite sides of the block 19, this
pivoted connection being so constructed as to leave the pawls free to move out and in
at their outer ends sufficiently far to fully enter and fully pass out of the ratchet
notches. The pawls a and care-pressed outwardly by springs 26 and 27, which are
held within housings formed in the collar 18 or extending into the 'body of the shaft
as shown in Fig. 2. The lateral displacement of the pawls is prevented by pins 25,
Fig. 4, which are driven or screwed radially through the block 19 so that they inter-
sect tangentially the sockets 21, 21 and enter grooves 12, 12, formed in the butt ends
of the pawls, as shown at Figs. 4, 8, and 9, so that while the pawls are free to vibrate
they are prevented from slipping out of their pivotal sockets.
The preferred construction of the ratchet notches bd is that shown, circular
recesses 15, 15 being bored out at diametrically opposite sides of the hub 13 and wear
plugs or blocks 16, 16 being inserted fast in the recesses. The bearing faces 17, 17 of
the plugs 16 are made slightly concave, being circular ares concentric with the pivotal
axes of the pawls a and c when the latter are in engagement with the notches b, d, as
shown in Figs. 4 and 5, and the ends of the pawls are also rounded in circular ares.
from the same axial centres. Essentially, the wheel B need be provided with only one
notch and one notch d; but preferably two notches of each kind are provided, as
shown, so that the same wear plug 16 serves as the. abutment face for both notches.
The number of notches may be still further multiplied, if desired.
Normally the driving wheel B is revolving in the direction of the arrow in the
several figures and the shaft C is stationary. Its pawl a and c being retracted are
drawn inwardly in order that their free ends may not engage with the ratchet notches.
The driving pawl a is held retracted by a can stop, E, which is formed with a
cam face, 36, which is normally arranged in the path of a projection, 42, formed
on the pawl a. This projection 42 extends outside the recess 14, as shown in
Fig. 3, and into the plane of the cam stop E. The shape of this projection 42
is best shown in Figs. 6 and S.
In order to provide means for engaging the clutch the cam stop E is made
movable at will in order to carry it out of the path of the projection 42, so that
the pawl a may be freed and be pressed outwardly by its spring.
This move-
ment of the cam stop may be in any suitable direction in order to carry it away
from the projection 42; but it is preferably in a direction away from the wheel B,
in which case it must move sufficiently far to bring it beyond the end of the
projection 42. To accomplish this movement the stop E is preferably made in
the form of a hinged leaf standing in a plane normally perpendicular to the axis
of rotation and parallel with and close to the inner face of the driving wheel hub
and pivoted on a horizontal axis at its lower side, as shown. In the construction
shown the hinged leaf is formed in one piece with its pintle 35, on the projecting
end of which is fixed a crank arm 38, the crank stud of which is jointed to the
upper end of a rod, 40, which extends down to the bottom portion of the press,
where it is jointed to the usual operating pedal, 39, which is drawn up by a
spring, 41. The tension of this spring holds the hinged leaf or stop E normally
in the position shown in full lines in Fig. 3, where it stands in the path of the
projection 12. When the treadle is depressed, the stop E is tilted in the manner
shown in dotted lines in Fig. 3, thereby freeing the projection 42 and permitting
the pawl a to fly outwardly, so that its free end 23 rides against the outer wall
of the recess 14, as shown in Fig. 7. When in the rotation of the wheel B the
next approaching ratchet notch bencounters the pawl, the latter enters this notch
and its end abuts against the working face 17 of the wear plug 16, whereupon
this plug drives the pawl before it and through the medium of the pawl it drives
the shaft around with the wheel. If, as is usually the case the treadle be released
before one revolution is completed, the cam stop E moves back into the path of
the projection 42, and at the end of the revolution the projection rides upon the
cam face 36 and lifts the pawl out of the notch b, thereby disengaging the 5
clutch. The cam face 36 is of such contour that the rise from the forward edge

page_text: (which is first encountered by the projection 42) is at first slight, but toward the
rear edge the rise becomes more abrupt, forming a considerable cain projection, 37.
The gradually rising cam face 36 first acts to lift the pawl with a comparatively
slow movement until it is lifted quite free from the notch, whereupon, if the
momentum of the shaft be inconsiderable, or if the retardation due to the work it
is performing be great, the shaft will instantly come to rest. If, however, the
momentum of the shaft tends to carry it beyond its normal position of rest, the
projection 42 will be brought against the abrupt rise 37 of the cam face, which
will still further lift the pawl until its inner side is brought into firm abutment
with the flat face or shoulder 49 on the collar 18, so that by this abutment the pawl
becomes essentially a fixed arm or projection from the shaft, which, tending to
rotate concentrically around the axis of the shaft, is resisted by the abrupt cam
projection 37, whereby the further rotation of the shaft is prevented and the shaft
is absolutely stopped at a certain limited point of its rotation.
As the exact position of the cam face of the stop E must be maintained to
insure perfect operation, and as the stop is subjected to considerable strain, it is
important to provide the stop with an adjustable and at the same time a firm
and unyielding supporting bearing. The preferred construction for this purpose is
that shown, where the pintle 35 is carried in a cylindrically grooved bearing in a
block, 32, which block is socketed in the lower part of a case, 30, which is
bolted to the frame A of the press. The block 32 is mounted to slide vertically
in its socket in the case 30, and is adjusted up or down by a screw, 45, and
when in the proper position is fastened by bolts 33, 33, passing through slots in
the block and screwing into the press frame. The case or frame 30 is preferably
an annular case inclosing the shaft and having a central opening, 31, elongated
to one side in order that in being passed over the shaft it shall admit the collar 18,
block 19, and pawls a and c through this opening.
When the clutch is engaged and the driving pawl becomes seated in the ratchet
notch b, the opposite retarding notch, d, is in a position coincident with the free
end of the retarding pawl e and is entered by the latter, as shown in Figs. 4
and 5, so that the shaft is prevented from revolving faster than the driving wheel,
whereby the wheel and shaft are positively connected together in both directions.
This is an important provision in power clutches wherein there is a tendency of
the shaft to revolve faster than the driving wheel by reason of the weight of the
plunger, which acts to assist the movement of the shaft during its downstroke.
In order to prevent the clicking noise which would otherwise be occasioned by
the free end of the retarding pawl dropping into the successive ratchet notches
during the rotation of the driving wheel while the clutch is disconnected, and to
avoid the consequent wear of the end of the pawl, I provide a stationary throw
off cam, 44, which is shown as a block secured to or made integral with the
annular case 30. This cam 44 has a cam face formed to gradually approach the
centre of rotation and arranged in such position that when the retarding pawl, in
the course of its rotation, nears the end of the revolution a lateral projection, 43,
formed on the side of the pawl, shall encounter this inclined cam face and in
riding over it shall be displaced inwardly by it, whereby the pawl c is retracted
out of engagement with the ratchet notches, as best shown in Fig. 6. The pawl
remains thus retracted as long as the shaft remains at rest. Upon the next
engagement of the clutch the first movement of the shaft carries the pawl imme-
diately beyond the abrupt end of the cam block 44, whereupon the pawl is released
and its free end moves outwardly into engagement with the notch d.
The cam block 44 does not interfere with the driving pawl a for the reason that it is
arranged in a transverse plane beyond the end of the projection 42, as is clearly shown
in Fig. 3. On the other hand, the cam stop E does not interfere with the retarding
pawl, for the reason that the projection 43, being made narrower than the projec-
tion 42, does not extend far enough radially to touch the cam stop E in its
revolution.

page_text: It it be desired that the shaft shall turn more than one revolution, the operator will
hold the treadle depressed, thereby holding the stop E out of the path of the projec-
tion 42, so that the driving pawl in passing the stop will not be engaged and retracted
thereby. When as many revolutions have been made as are desired, the operator will
release the treadle and the shaft will then be stopped at the completion of the revolu-
tion then being made. In thus driving the shaft continuously the retarding pawl is
retracted by the cam block 44 at each revolution; but as this occurs at the top of the
stroke of the plunger, where there is no tendency to drive the shaft faster than the
driving wheel, the momentary release of the retarding pawl at this point in the revo-
lution is not objectionable.
The foregoing description sets forth the specific construction which I prefer to
employ in the embodiment of my invention; but it is obvious that the construction
might be changed in many ways and the parts might be differently arranged without
departing from the essential features of my invention. For example, the pawls instead
of being pivoted to the inner of the two concentric parts and engaging notches in the
outer part, might be pivoted to the outer part and engage notches in the inner part;
also the pawls, instead of being borne by the driven part, which is normally at rest,
might be borne by the driving part, so as to be normally in revolution with it. These
modifications of my clutch are embodied in the construction shown in Fig. 10, wherein
the pawls a and c are represented as being mounted in recesses formed in the wheel
hub instead of being connected to the shaft, and the notches band d are represented
as being formed in the block 19, which is fixed to the shaft.
with toes 42 and 43", respectively, which take the place of the projections 42 and 43
The pawls are formed
in the construction first described, the toe 42 being narrower than the toe 43ª, in
order that it may freely pass an inclined faced block, 50, which acts to throw the
retarding pawl c out of engagement with its notch d.
similarly to the construction first described, and its cam face acts upon the toe 42ª in
The cam stop E is mounted
passing to throw its free end out and prevent its engagement with the abrupt face 9
of its notch b.
I have shown the pawls as being pressed out by springs; but it will be understood
that gravity may be substituted as an equivalent for spring pressure. This may be
done in the case of the pawl which, in the position of rest, is arranged at such point in
the revolution that its weight tends to throw it into the notch.
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 in respect of clutches is :-
1. The combination, with rotative driving and driven parts, the one formed with a
ratchet notch, of a driving pawl pivoted to the other part and tending to thrust its
free end into said notch, and a cam stop arranged in position to be encountered by
said pawl in its rotation and adapted to retract it from engagement with said notch,
whereby the clutch is disengaged, and said stop mounted to be displaced at will from
the path of said pawl whereby the latter may be released and the clutch engaged,
substantially as set forth.
2. The combination, with rotative driving and driven parts, the one formed with a
ratchet notch, of a driving pawl pivoted to the other part, a spring tending to thrust
the free end of said pawl into said notch, and a cam stop having a cam face in position
to be encountered by the pawl in its rotation, and shaped to move the pawl, as the
latter rides over it, out of engagement with said notch, whereby the driven part is
stopped, and said stop mounted to be displaced at will from the path of said pawl,
whereby the latter may be released to engage the clutch, substantially as set forth.
5
3. The combination with rotative driving and driven parts, the one formed with a
ratchet notch, of a driving pawl pivoted to the other part, a spring tending to thrust
the free end of said pawl into said notch, and a cam stop having a cam face in position
to be encountered by the pawl in its rotation and shaped to move the pawl, as the
latter rides over it, out of engagement with said notch, and subsequently to resist the 5

page_text: further rotative movement of the pawl and thereby stop the driven part, and said stop
mounted to be displaced at will-from the path of said pawl, whereby the latter may be
released to engage the clutch substantially as set forth.
4. The combination, with rotative driving and driven parts, the one formed with a
ratchet notch, of a spring-pressed driving pawl pivoted to the other part and formed
with a lateral projection beyond the plane of said notch, and a. stationary cam stop
arranged in position to be encountered by the lateral projection of said pawl in its
rotation and shaped to move the pawl, as said projection rides over its cam face, out of
engagement with said notch, substantially as set forth.
5. The combination, with rotative driving and driven parts, the one formed with a
recess and having a ratchet notch in the defining wall of said recess, of a spring-
pressed driving pawl arranged within said recess pivoted to the other part and formed
with a lateral projection extending outside of said recess, and a stationary cam stop
arranged in position to be encountered by the lateral projection of said pawl in its
rotation and shaped to move the pawl, as said projection rides over its cam face out of
engagement with said notch, substantially as set forth.
6. The combination with rotative driving and driven parts, the driving part formed
with a ratchet notch and the driven part carrying a spring-pressed driving pawl and
formed with a shoulder or abutment for limiting the retractile movement of said pawl
when disengaged from said notch, of a stationary cam stop having a cam face in
position to be encountered by the pawl in its rotation and formed with a gradual
incline, which is first encountered by the pawl and is shaped to move the pawl out of
engagement with said notch, and an abrupt projection which is subsequently
encountered by the pawl and which, when the pawl is seated against said shoulder or
abutment, resists the further rotative movement of the pawl and thereby of the driven
part, substantially as set forth.
7. The combination, with rotative driving and driven parts, the one formed with a
recess having a ratchet notch in its defining wall, of a spring-pressed driving pawl
within said recess pivoted to the other part and formed with a lateral projection
extending outside of said recess, and a stationary cam stop consisting of a plate or leaf
arranged in a plane perpendicular to the axis of rotation and formed with a cain face
on one side arranged to be encountered by the lateral projection of said pawl in its
rotation, and a bearing frame or support for said cam stop adapted to hold the same
against the thrust against it of said pawl, substantially as set forth.
8. The combination, with rotative driving and driven parts, the one formed with a
ratchet notch, of a driving pawl pivoted to the other part, a spring for pressing out
said pawl, a cam stop arranged in position to be encountered by said pawl in its rota-
tion and adapted to retract it from engagement with said notch, said stop mounted to
be displaced at will from the path of said pawl, and a bearing part in which said stop
is mounted, constructed to be adjustable in order to bring the cam stop nearer to or
farther from the axis of rotation, substantially as set forth.
9. The combination, with a rotative driving part formed with a recess open at one
side and having a ratchet notch in the defining wall of said recess, a rotative driven
part, and a spring-pressed driving part pivoted to the driven part, arranged to rotate
within said recess, and formed with a lateral projection extending out at the open side
of said recess, of a stationary cam stop consisting of a plate or leaf formed with a cam
face on one side arranged to be encountered by the lateral projection of said pawl in
its rotation and mounted on a pivotal axis, whereby it may be vibrated at will to bring
its cam face beyond the end of said lateral projection, substantially as set forth.
10. The combination, with a normally stationary driven shaft formed with a pro-
jecting boss and a spring-pressed driving pawl pivoted to said boss, of a normally
revolving driving wheel mounted on said shaft and formed with a recess in one side
inclosing said boss and pawl and with a ratchet notch in the wall of said recess and a
stationary cam stop arranged in position to be encountered by said pawl in its
rotation and shaped to move the latter out of engagement with said notch, substantially
as set forth.

page_text: 11. The combination, with rotative driving and driven parts and a clutch for
coupling them together at will, one of said parts formed with a retarding notch, of a
retarding pawl pivoted to the other part and arranged to enter said notch while the
driving clutch is engaged, and a stationary throw off cam arranged to withdraw said
pawl from said notch at the part of the revolution at which the driving clutch is 5
released, substantially as set forth.
12. The combination, with rotative driving and driven parts, the former formed with
a retarding notch, and a clutch for coupling them together at will, of a retarding pawl
pivoted to the driven part and arranged to enter said notch while the driving clutch is
engaged, and a stationary throw-off cam arranged to retract said pawl from said
notch when it reaches its position of rest, whereby the clicking and wear of the
retarding pawl during the free revolution of the driving part are prevented, substan-
tially as set forth.
13. The combination, with rotative driving and driven parts and a clutch for
coupling them together at will, one of said parts formed with a retarding notch, of a
retarding pawl pivoted to the other part, arranged to enter said notch while the
driving clutch engaged, and said pawl formed with a lateral projection extending
out beyond the plane of said notch, and a stationary throw-off cam arranged in the
path of said lateral projection and shaped to move the retarding pawl as said pro-
jection rides over it out of engagement with said notch, substantially as set
forth.
14. The combination, with rotative driving and driven parts formed with ratchet
driving and retarding notches, of driving and retarding pawls arranged to enter the
respective notches, a cam stop for disengaging the driving pawl, and a throw-off cam
for disengaging the retarding pawl, the two arranged in different planes, and a lateral
projection on the driving pawl extending into the plane of said cam stop, and a lateral
projection on the retarding pawl extending into the plane of said throw off cam,
substantially as set forth.
15. The combination, with rotative driving and driven parts formed with ratchet
driving and retarding notches, of driving and retarding pawls arranged to enter the
respective notches, lateral projections on said pawls, and one projection extending
farther than the other, and the shorter projection extending farther from the centre
than the other, and a cam stop for disengaging the driving pawl, and a throw-off cam
for disengaging the retarding pawl, the two. arranged in different planes of the paths,
respectively, of the shorter and longer lateral projections, and the one in the path of
the shorter projection being farther from the centre than the other, whereby it is not
encountered by the longer projection, substantially as set forth.
16. The combination, with rotative driving and driven parts, one of said parts
formed with ratchet driving and retarding notches, of a driving and a retarding pawl
pivoted to the other of said parts and arranged with their free ends projecting in
opposite rotative directions and arranged to simultaneously engage said notches, and
a stop for retracting and releasing the driving pawl at will to engage.the clutch
substantially as set forth.
17. The combination, with rotative driving and driven parts, the one constructed
with a recess, 14, in one side, with a ratchetinotchiformed in the defining wall of said
recess, and a socket, 15, beyond said notch, with a wear plug, 16, fixed in, said socke
and having an abrupt face, 17, arranged to form the bottom of said:notch, and with
driving pawl pivoted to the other part and adapted to engage said notch, substantiall
as set forth.
18. The combination, with rotative driving and driven parts, of driving an
retarding pawls pivoted to the one part and the other part constructed with corre
sponding ratchet notches arranged in pairs, with a fixed wear plug inserted betwee
them and having abrupt wearing faces formed on.its opposite sides to constitute th
bottoms of said notches, substantially as set forth.
19. The combination, with a driven shaft, a driving wheel turning loosely thereo
and formed with a recess in one side having a ratchet notch in the defining wa

page_text: thereof and a driving pawl within said recess pivoted to the shaft, and having a lateral
projection extending outside of said recess, of a cam stop arranged in the path of said
projection, a bearing block in which said cam stop is mounted, and a fixed frame
having a socket in which said bearing block is adjustably fastened, substantially as set
forth.
20. The combination, with a driven shaft, driving and retarding pawls pivoted
thereto and having lateral projections, a driving wheel turning loosely on said shaft
and formed with a recess in one side inclosing said pawls, and with ratchet notches in
the defining wall thereof, and a cam stop for disengaging said driving pawl, of a fixed
frame encircling the shaft formed with a stationary throw-off cam for disengaging the
retarding pawl, and with an adjustable bearing for said cam stop, substantially as set
forth.
4209
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Patent Agent.