Year: 1898

page_text: I; ARTHUR HERSCHMANN, of Fern Place, Brighouse, Yorkshire, Engineer, do
hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in a construction of friction clutches
and its object is to provide a simple and effective means by which such clutches
can be put into and out of operative position at will.
In the construction of these clutches I propose to employ tubes or cushions
which can be inflated with air or filled with liquid. These cushions or tubes
bear against shoes or friction blocks belonging to one part of the clutch which
can press against the other part of the said clutch when the tubes are expanded so
that connection is made. These tubes are inflated or filled automatically and
are constantly kept distended while the clutch is in operation.
The body of the clutch consists of a disc provided with a deep flange or rim
at one side serving if required as a pulley. Within this flange or rim a second
disc or disc like case is fitted and at the periphery of this case two or more shoes
or friction blocks are fitted. These are carried in recesses in the periphery of
the case so that they can move slightly radially, but always turn with the case.
The tubes or cushions above described are at the back of these blocks and lie in
grooves formed to receive them. When these cushions are inflated or filled they
will press the blocks out against the inside of the rim or flange and the two
parts will be caused to turn together coupling the pulley or shaft or other parts
according to the application of the clutch. These tubes or cushions are inflated
or filled by means of small pumps which are carried within the case connections
passing from the said pumps to the tubes. These pumps are actuated by means
of levers also carried by the case which project through openings at the side next
to the disc. To actuate the pumps these levers are oscillated by means of a cam
of peculiar form carried by the other part of the clutch. At the inside of the
disc a ring is fixed or an annular ledge is formed having a face groove extending com-
pletely around it. This groove is formed preferably at two points with a small
kink or bent part. The ends of the levers are provided with small friction rollers
which roll in the said groove, and when they meet the bent portion of the groove
the levers are caused to turn through a small angle working the pumps. Through-
out the remaining part of the revolution the levers are not actuated and the
friction rollers simply run along the grooves without other motion. This action
goes on whenever there is any relative motion between the two parts of the clutch,
so that if there is any slip the clutch will operate automatically to remedy it by
pumping a further portion of air or liquid into the cushions.
When the liquid is employed the disc like case is provided with a small chamber
around the hub, which serves to carry liquid, connections passing passing from,
this chamber to the pumps allowing the liquid not only to be pumped into the
cushions but also when the clutch is rendered inoperative, enabling the liquid
to pass back from the cushions to the chamber.

page_text: When the clutch is to be disengaged, a valve is employed, which allows the
air or liquid to escape from the pump without charging the cushions so that the
pump can be actuated without in any way disturbing the arrangement. This
valve I prefer to operate by means of a small electrical arrangement consisting
of a coil carried by the case provided with a core or armature which when a
current is sent through the coil by means of suitable contact rings and connections,
operates the valve and opens or closes it as the case may be. A spring may be
employed to return the valve to its normal position. The valve may also be
operated by means of a small lever which may extend outside the case, and which
can be operated by any suitable stop at will."
cam
arm
According to a slight modification instead of a disc like case being employed.
an inner disc is provided with a grooved flange or rim serving to receive a tube or
cushion. The friction blocks are carried in recesses in this flange, or by means
of separate pieces fixed on the flange, and are provided with springs
when the cushions
Instead of
for withdrawing them
are collapsed.
a small
above described,
the form of lever and
three armed
of which is connected to the pump
lever may be employed, one
and the other two are oscillated by means of rods or projections at the inside of
the outer disc which actuate the arms alternately and so oscillate the lever. A
small mechanical device may be employed in connection with this arrangement,
consisting of a bent lever, one end of which projects to the outside of the clutch
and engages with a clip by which the lever can be operated, this arrangement
enabling the valve to be opened so that the liquid or air may escape from the
cushions. Any number of cushions or tubes may of course be employed according
to the size and nature of the clutch.
A clutch constructed in this manner will be of especial service in connection
with the driving of dynamos. For such purpose a safety or blow off valve can
be employed which when any undue strain comes upon the clutch, will cause
the clutch to be released, the liquid or air escaping from the cushions. Springs
are provided for loading the valve which springs can be adjusted at will according
to the limit of the power which it is desired to transmit. The clutch will thus
be released should any sudden resistance occur on the driven side, thus preventing
any injury which might occur should power continue to be transmitted. The
liquid can be allowed to run back to the tank when the desired pressure is
exceeded.
A T1 1
1900
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.
Improvements in Friction Clutches.
I, ARTHUR HERSCHMANN, of 155, Pershore Road, Birmingham, late of Fern
Place, Brighouse, Yorkshire, Engineer, 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:―
This invention relates to improvements in the construction of friction clutches
and its object is to provide a simple and effective means by which such clutches
can be put into and out of operative position at will, and by which the contact
between the two portions of the clutch is automatically regulated.
In the construction of these clutches I propose to employ cushions or tubes
which can be inflated with air or filled with liquid and these cushions or tubes
'

page_text: operate shoes or friction blocks belonging to one part of the clutch which can
press against the other part of the said clutch when the cushions or tubes are
expanded, so that connection is made. These cushions or tubes are inflated or
filled automatically and are constantly kept distended while the clutch is in
operation.
To inflate or fill the cushions with the air or liquid, a pump is employed operated
in an automatic manner. This pump is operated only when there is a relative
motion between the two parts of the clutch, so that any slip in the case of the
driven part will cause the pump automatically to work, pressing the friction blocks
more firmly against the contacting part. To release the clutch a special device
is employed which relieves the pressure in the cushions so that the pump although
it is still actuated does not operate the clutch.
I use for preference a liquid to fill the cushions and expand them, and the
apparatus is provided with a small reservoir having connections to the cushions
by which the liquid may be introduced to them or allowed to flow from them back
to the reservoir. In the case of air, no reservoir is required as the air is pumped
from the atmosphere and allowed to escape into it.
The arrangement for releasing the clutch consists simply of a valve or cock
which allows the fluid to flow out from the cushions as fast as it is forced in,
the flow in the case of liquid being back to the reservoir.
In order that the invention may be more clearly understood, reference is had to
the accompanying drawings, in which Fig. 1 is an elevation partly in section of
a friction clutch constructed according to my invention, Fig. 2 is a sectional
elevation of the same at right angles, Figs. 3 and 4 are somewhat similar views
of a slightly modified arrangement, Fig. 4 being taken on the sectional liner y
Fig. 3, and Fig. 5 is a detail view showing a further modification.
Referring to Figs. 1 and 2, on the shaft A is fitted the disc B formed with the
rim 6 which may serve as a pulley where necessary. The second shaft C which
is in line with the shaft A carries the friction blocks D which consist of a crescent
like extension pivoted at each side of the main casing E, which is fixed on the
shaft. This casing is provided with the chamber or reservoir F which carries
the oil or other liquid employed in operating the clutch. To each side of the
casing a small cylinder G is fitted screwing into a socket formed in the casing.
According to the arrangement shown, this cylinder carries a small piston r
plunger g on the end of the rod g¹ and around this rod a spring is placed
bearing upon the piston or plunger. The rod is provided with the head g³
which is connected to friction blocks by the toggle lever joint H. A cylinder
with its accompanying parts is provided for each pair of friction blocks. In the
inner end of the cylinder the diaphragm J is placed of leather or other suitable
material. This forms a cushion as the chamber at the underside of the diaphragm
is connected with the liquid reservoir F in the manner hereafter described.
From one side of the reservoir F the pipe f passes to a small pump at the other
side of the casing, the pipe being provided with the valve f which allows the
liquid to be drawn through the pipe, but prevents its return to the reservoir.
The pump K consists of a small plunger working in a cylinder or barrel, and
the liquid is drawn when this plunger is operated into the said barrel through the
pipe f and thence ejected on the return stroke into the pipe L provided with the
small valve which prevents any return of liquid. This pipe is connected to the
annular pipe M which is partly broken away in order to show the details more
clearly and the pipe m passes to the cushion or chamber formed by the diaphragm.
This pipe is not shown for the upper cushion in Fig. 1, this being in section.
The action of the pump is thus to force the liquid from the reservoir through the
annular and other pipes into the two cushions causing them to expand. On
these expanding the piston g will be caused to rise into the cylinder against the
force of the spring and the toggle joint will force the friction blocks or shoes
tightly against the inner surface of the rim b, thus forming a frictional connection
between the two parts. The plunger of the pump is operated by the lever N which

page_text: on oscillating around its pivot reciprocates the plunger. This plunger is oscillated-
by means of the cam slot 0 in the internal boss belonging to the disc B. This,
slot is provided with a small kink or bend at one or more parts and the pin or
roller n
belonging to the lever extends into this slot. Thus whenever there is.
any relative motion between the two shafts or two main parts of the clutch,
the roller or pin n will travel around its slot and be operated by the bent portion.
This actuates the pump automatically so that the liquid is constantly being forced
into the annular. tube M and thence into the cushions excepting when a special
outlet to be described is provided. The pressure in the cushions is thus always
augmented whenever there is any slip, so that the clutch is kept automatically.
efficient.
To release the clutch the fluid pressure in the cushions is relieved and this. is
effected through the pipe P passing from the annular pipe M back to the reservoir.
The passage is closed or opened by the valve or cock 2 which is operated by
an external arrangement. When the passage is open the liquid instead of being
forced into the cushions against the pressure of the spring, will simply pass back
to the reservoir and the springs will withdraw the friction shoes from the bearing
surface of the clutch. This cock is operated by means of the rod p sliding in
the guide and provided with the small spring p³ which causes it normally to
keep the cock or valve closed so that the passage for the liquid back to the reservoir
is cut off. This rod is operated by the rocking lever Q which is formed with
three armis one of which engages with the rod and operates it through the small
collar. An arrangement is provided by which the clutch is automatically
released on too high a speed being obtained, the rocking lever Q being used for this
purpose. To the arm of this lever which may be weighted, is connected the rod q
supported by a guide at its other end and furnished with the spring which can
be adjusted so as to make the arrangement operative at any predetermined
speed.
When too high a speed is obtained the lever Q will turn owing to centrifugal
force the heavier part tending to move outwards. The lever will then act against
the collar and will open the cock P. A small catch is provided in connection
with this arrangement consisting of a fixed rod 75 carrying the spring 6, which
consists of a thin spring plate pressing against the collar 7. When the rod p
is. pushed out against this spring 26 it will, when the motion is sufficiently great,
pass the spring and be prevented from returning. This catch is only applied.
when the speed has greatly exceeded the desired limits, and in this case the clutch
is held inoperative until the shaft has been stopped and the catch returned to
its normal position. When the speed only slightly exceeds the limit, the rod.
operating the cock will be returned to its normal position on the speed becoming
lower, and the clutch will again become operative the arrangement being thus
entirely automatic.
To release the clutch at will, the forked lever R is employed, the fork extending
around the shaft C. This lever is pivoted at r and when moved into operative
position bears against the arm. 3 of the lever pressing it inwards and turning
the lever so as to open the cock P. This action can also be performed by a
simple electrical arrangement, consisting of an electro magnet and armature,
Various devices can of
which when a circuit is completed, opens the cock.
course be used for effecting the desired action of the cock at will.
In the arrangement shown in Figs. 3 and 4, the construction is slightly different,
but the essential features are the same. The reservoir F is in this case in the.
same part of the casing as the pump, so that the liquid is pumped directly from the
chamber instead of passing through external pipes. The plunger K' is provided
with the central passage opening into the reservoir at one end and through
this passage the liquid is pumped. The plunger is provided with the delivery
valve at the end of its passage and the valve is placed near the other end
of the plunger. Passages m' pass from the chamber in which the valve is
placed to the liquid cushions or flexible chambers formed by the diaphragm J.

page_text: These passages m¹ have the same purpose as the pipes M and m. A pipe P¹ is
connected with the passages p and 28 and provided with the valve or cock p
to allow the liquid to pass into the reservoir when the cock is operated as described
in connection with Figs. 1 and 2. The lever M works the pump plunger in the
samo manner as in the first figures, but instead of the can slot actuating the
lever being formed around the boss on the disc B, a plate o' is provided having a
surface slot O with a kink or bend at one or more parts so that on one part of
the clutch turning relatively to the other, the lever will be oscillated and the pump
will work.
The valve or cock p is operated in this arrangement by means of the lever S pro-
vided with a connection to the cock. This lever is formed with the extension s
extending along the shaft C and also has the adjusting spring s which normally
keeps the cock closed, and closes it when the lever is released. The end of the
extension is adapted to engage with the lever arm T provided with weight t
at its end. This lever arm is pivoted at to a fixed bracket and is moved by
suitable connections at 2. On the lever being moved sideways the extension s
which is bent at its extremity is pulled to the side and the lever S is moved against
the force of the spring so as to open the cock p.
In the arrangement shown in Fig. 5 another form of friction block or shoe is
employed consisting of a block II carried in a groove in the rim e of the casing E
which is of different form from that shown in the other figures to suit the modified
arrangement of friction shoes. The block D' is secured in its slot by the screw
pin U provided with the spring u and the adjusting nut u¹. The pin passes
through the rim e and the spring withdraws the block when the fluid pressure *
either air or liquid is relieved.
In place of the pistons and other connections shown in the earlier figures, a
direct action of the pressure is employed, the fluid being pumped into the tubes
or cushions J placed at the back of the blocks in grooves in the said blocks
and in the rim e. When these cushions are inflated or filled, the blocks will he
pushed directly outwards against the inner side of the rim b, the action being
practically the same as that already described. Any number of friction blocks
or shoes may be of course employed in place of those shown in the drawings, and
the number of cushions used will of course depend upon the friction blocks.
The arrangements in Figs. 1 to 4 have been described with reference to liquid
pressure in the cushions but if air pressure is employed the arrangements are
practically the same, the reservoir being dispensed with and the supply and dis-
charge pipes opening to the atmosphere.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is:-
1. In a friction clutch, the combination with friction blocks or shoes and
cushions supplied with fluid pressure, of a pump carried by one part of the
clutch, connections between the pump and cushions, a discharge pipe from the
cushions and parts actuating the said pump on one part of the clutch moving
relatively to the other, substantially as described and for the purposes specified.
2. In a friction clutch, the combination with friction blocks or shoes and
cushions adapted to be filled with air or liquid and to apply the friction shoes
by fluid pressure, of a pump, connections between the said pump and cushions for
supplying the fluid, a discharge pipe and a lever operating the pump, these parts
being carried by one side of the clutch, and a cam slot or groove on the other part
of the clutch oscillating the lever and working the pump when there is relative
motion between the two main parts, substantially as described and for the purposes
specified.
3. In a friction clutch, the combination with friction blocks or shoes and
cushions actuating the said blocks and supplied with air or liquid, of a pump
carried by one part of the clutch, connections reciprocating the said pump when

page_text: there is relative motion between the two sides of the clutch, pipe connections
from the pump to the cushions, a discharge pipe from the cushions and a cock
connected to the discharge pipe, actuated by a mechanical or other device to allow
the fluid to escape from the cushions when desired, substantially as described and
for the purposes specified.
4. In a friction clutch, the combination with friction blocks or shoes, cushions
adapted to apply liquid pressure to the said blocks or shoes, and a liquid reservoir
in the casing of the clutch, of a pump, a lever actuating the said pump, a cam
slot oscillating the lever when there is any relative motion between the two parts
of the clutch, connections from the reservoir to the pump and from the pump to
the cushions, an escape pipe from the cushions back to the reservoir, a cock
fitted to the said escape pipe and connections from this cock to the exterior of
the clutch allowing the cock to be turned at will so as to permit of the liquid
passing back to the reservoir relieving the pressure in the cushions, substantially
as described and for the purposes specified.
5. The improved friction clutch comprising friction shoes or blocks, liquid
cushions applying the said friction shoes, a reservoir containing liquid, a pump
automatically actuated by the relative motion of the parts of the clutch, connections
between the cushions, pump and reservoir, and controlling apparatus, all con-
structed and operating substantially as described and shown in the drawings and
for the purposes specified.
Dated this 7th day of November 1898.
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.