Improvements in Fluid Pressure Friction Clutches.
Year: 1897

page_text: .Date of Application, 5th Jan., 1897-Accepted, 15th May, 1897
'
COMPLETE SPECIFICATION.
Improvements in Fluid Pressure Friction Clutches.
I, GEORGE MARK RICHARDS, Mechanical Engineer, of St. Paul, Minnesota,
United States of America, 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 fluid pressure friction clutches, its
object being to provide means for applying pressure to produce requisite friction
between the driving and driven elements, automatically operative only when and
so long as there is relative movement between said elements, either of said elements
serving as the driver, and rotating in either direction.
To this end the invention consists in providing the machine elements of the
clutch mechanism with opposed friction pieces of surfaces, one of said pieces being
relatively fixed. and the other relatively movable to and from the same, as actuated
by the applied pressure, and in providing the element which carries the relatively
movable friction piece, with an expansible fluid chamber for actuating said friction
piece, and an elastic fluid reservoir, and interposing between said chamber aud,
reservoir a pump connected with both adapted to be actuated by engagement with..
the other machine element when and so long as there is relative movement between
said elements.
The invention further consists in the features of construction hereinafter more
particularly described and claimed.
In the accompanying drawings forming part of this specification;
Fig. 1 is an end elevation of the improved clutch, showing the pump and fluid
reservoir;
Fig. 2 is a vertical, longitudinal section of the same on line 2 of Fig. 1,.
disclosing the fluid pressure chamber, fluid reservoir, friction pieces, valve actuating
mechanism and shifting sleeve;
Fig. 3 is a cross section on line x-x of Fig. 2;
Fig. 4 is a cross section on line y-y of Fig. 2;
Fig. 5 is a detail cross section through the fluid reservoir, pump and connected
valves;
Fig. 6 is a detail section on line m-m of Fig. 5, and,
Fig. 7 is a detail of one of the springs for positively throwing out of engagement
the friction pieces of the clutch elements when pressure thereon has been removed.
As shown in the drawings, 2 represents the shaft, 3 the sleeve or hub secured
thereon by the key 4. 5 is an annular flange or frame having openings through
its web to receive the friction blocks 6. The pulley 7 is secured by the key 8 upon
the hub 9, which is journalled loosely upon the shaft 2. This hub carries a shell
enclosing the flange 5, made up of the annular flange 10 integral with the hub 9,
and having peripheral projections 11.
The cylindrical part 12 has lips 13 to overlap the projections 11 when turned
into contiguous position, the spaces between the lips being sufficient to permit the
entry of the projections 11 when the parts are slipped into place, one part then
being given a relative turn with reference to the other, so as to interlock the
projections and lips. They are then secured together by means of the bolts 14.

page_text: The cylindrical part 12 has an annular flange 15, provided on its inner face with a
wide, shallow annular channel 16. for; the fluid pressure chamber. Covering this
channel to form said chamber, and bearing upon the shoulder 17, is the flexible,
elastic diaphragm 18, the same being secured in place by means of the annular
rings 19 and 20 held with sufficient pressure upon the diaphragm by means of the
spring wire rings 21 and 22 wedged between the rings 19 and 20 and the lips 23
and 24.
Upon the outside of the diaphragm is seated the annular friction plate 25, which
is provided with peripheral lugs 26, engaging inwardly projecting lugs 27 upon the
inside of the cylinder 12, whereby when in place said plate is prevented from
rotative slip. The friction plate is held normally thrust inward upon the diaphragm
and away from the friction blocks 6 by the spring 28, one end of each of which
is secured on the outside of the lips 13 by means of the screw 29, the other end
of the spring passing through an opening 30 in the lip, and bearing upon the
projection 26. The adjacent opposed face of the flange 10, and the friction plate 25
are the bearing surfaces for the opposite sides of the blocks 6, the blocks thus
being clutched between these surfaces in the operation of the mechanism, as here-
inafter described. The flange 15 is fitted to, and turns upon, the hub 3, as a
bearing when the two parts of the clutch are running out of engagement. Mounted
upon the flange 15 is the pump cylinder 31, connecting with which is the fluid
passage 42. One end of the passage communicates with the port 43, which is
closed by the valve 44, actuated by its spring 45. The valve chamber 46
communicates through the port 47 with the fluid pressure chamber 16. The other
end of the passage 42 communicates with the valve chamber 48, which has a
port 49 closed by the valve 50, as actuated by its spring 51.
The port 49 communicates with the short cylinder or tube 52, to which is coupled
the flexible hose 53 by means of the clamping rings 54. The hose is arranged
concentrically upon the flange 15, being.held in place and protected by the shield 55
(see Fig. 1). The other end of the hose is coupled to the short cylinder 56 by
means of the clamping rings 57.
Arranged in the cylinder 56 is the plug valve 58, which controls communication
between the hose and the port 59 leading to the pressure chamber 16. The valve 58
is provided with a segmental pinion 60 engaged by the segmental gear 61, which
has pivotal support upon the arm 62 secured to the disc 15. The opposite end of
the pivot 63 of the segmental gear carries the fingers 64 and 65, by means of which
the pivot may be turned so as to actuate the segmental gear, and thus open or
close the valve 58.
66 is an eccentric shifting sleeve slidably mounted on the hub 3, and held from
turning thereon by the feather 67. It is provided with an annular groove 68, with
which any suitable operating mechanism may be connected. This sleeve has a
circumferential rib 69, which extends between and is adapted to engage the
fingers 64 and 65, and to turn the same as the sleeve is shifted. The pump lever 70
is connected by the pivot 71 with the disc 15. The power end of the lever, 701
carries an antifriction roll 72, which rides upon the eccentric shifting sleeve 66,
when the same is thrown into position to be engaged thereby.
To the other end of the lever is connected by the pivot 73 the piston rod 74.
The rod 74 extends into the cylindrical hollow piston 75, the inner dimensions of
which are greater than the rod, and is screw-threaded into its head, the rod being
flattened near its end at 76, so as to be slightly flexible, to adapt itself to the arc
of movement of the lever 70.
The piston 75 is fitted closely to the pump cylinder, suitable packing 77 being
fitted between the piston and the enlarged portion 78 of the cylinder. The sleeve 79
of the same inner dimensions as the main part of the pump cylinder is fitted into
the enlarged end of the pump cylinder, the end thereof being inwardly beveled so
as to press with a wedging action upon the packing. Interposed between the top
of the sleeve 79 and the shoulder or collar 80 on the piston rod is the coil spring 81,
which tends to crowd the sleeve 79 against the packing with a downward thrust of

page_text: the pump lever, so as to tighten the packing about the same, the pressure being
slightly relieved with the reverse motion of the lever.
As clearly appears in Fig. 5, the pump is operated by the antifriction roll 72,
travelling over the periphery of the eccentric sleeve 66. Any suitable fluid may
be used to furnish the required pressure, but I prefer some practically non-
compressible and non-freezable liquid, such as a suitable oil, which is poured into
the pressure chamber by removing the screw plug 82 until the chamber and the
connected hose or reservoir are filled, the friction parts being out of engagement,
it being essential that there shall be no air. left in either the chamber, hose or
connected passages, these parts thus constituting a circulating system for the
fluid.
The pulley and flanges 10 and 15 constitute the driving machine element; the
shaft, its flange 5, and blocks 6 constitute the driven element, and the friction
plate 25 and pressure chamber constitute the friction device.
The clutch is operated as follows; Supposing the elements to be out of
engagement, the shaft at rest, and the pulley turning loosely thereon. By any
suitable means not shown, the sleeve 66 is thrown inward or toward the clutch
into the position shown in Fig. 2, thereby bringing it into engagement with the
autifriction roll 72 of the pump lever 70. The driving element, made up of the
pulley and the other described and connected parts, in its rotation carries the roll 72
around the eccentric sleeve, setting the pump into operation, so as to start the flow
of the contents of the hose or reservoir into the chamber, to expand the same and
carry the friction plate 25 into engagement with the blocks 6, and at the same time
force them against the flange 10. As the pump begins to operate, the flange 69
engaging the finger 65, turns the valve 58 so as to cut off the reflow of the
contents of the pressure chamber into the reservoir or hose. The pressure of the
friction plate upon the blocks, and of the blocks upon the flange 10, is gradually
increased by the enhanced pressure of the fluid in the pressure chamber under the
continued operation of the pump until the friction is sufficient to prevent further
slip or relative movement between the two elements, and the flange 5 and connected
parts are rotated..
Should the load or the resistance to the turning.of the shaft 2 be increased so as
to cause slip between the two elements of the clutch, this slip or relative movement
causes the pump to operate and force more of the contents of the hose into the
pressure chamber, and increase the pressure and friction until the slipping is
checked..
It will thus be seen that when the sleeve has been thrown into operative
connection with the pump, the pump is automatically started and continues to
operate whenever, and so long as, there is any slip or relative movement between
the two elements.
When it is desired to stop the shaft, the eccentric sleeve is shifted in the
opposite direction, opening the release valve 58, and disengaging the roll 72, so as
to stop the operation of the pump, whereby the contents of the pressure chamber
are allowed to escape into the hose or reservoir, while the inflow from the reservoir
ceases with the operation of the pump. At the same time the tension of the
springs 30 thrusts the plate 25 away from the blocks and prevents friction or
contact between them.
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 is :-
:-
1. In a device of the class described, the combination with, the driving and
driven elements, of the interposed friction device, and automatic mechanism for
operating said friction device mounted upon one element and engaged by the other
element, whereby said mechanism is actuated whenever and so long as there is
relative movement between said elements.
.
2. In a friction clutch, the combination with the driving and driven elements, of

page_text: the friction device, its automatic operating mechanism carried by one element and
normally engaging the other element so as to be in action whenever and so long as
there is relative movement between said elements, and means for throwing the said
mechanism out of such engagement, and consequently out of action.
3. In a fluid pressure clutch, the combination with the two elements or members
thereof, of the interposed friction device, and automatic means for actuating
said device while there is relative movement in either direction between said
elements.
4. The combination with the fluid. pressure clutch, having a fluid chamber
interposed between its members, of the flexible diaphragm closing said chamber,
the friction plate actuated by the diaphragm, the supply pump, and automatic
means for actuating the pump only when there is relative movement of the clutch
members.
5. In a clutch of the class described, in combination the driving and driven
elements, the fluid pressure chamber, the collapsible fluid reservoir, the pump for
forcing the contents of said reservoir into the chamber, the relief valve for
permitting the return of the contents of the chamber into the reservoir, automatic
means for actuating said pump while and so long as there is relative movement
between said elements, and means for throwing said pump out of action and
opening said relief valve.
6. In a friction clutch, the combination with the driving and driven clements
thereof, of a pressure creating mechanism carried by one of said elements and
automatically operated by the relative movement between said elements, and the
pressure releasing mechanism acting in opposition to said pressure creating
mechanism.
7. In a clutch of the class described, the combination with the friction parts, of
the fluid circulating system carried by one clutch element or member, made up of
an expansible pressure chamber, a connected collapsible reservoir, suitable valve
connections, a pump for forcing the fluid of the system into said chamber, means
carried by the other element for automatically actuating said pump during relative
movement of said elements, and means for mechanically stopping said pump and
releasing the contents of said chamber.
8. In a clutch of the class described, in combination, the shaft, the circular
flange carried thereby having openings through its web, the friction blocks
arranged in said openings, the pulley journalled on said shaft, the web or flange
carried thereby adapted to bear upon one face of said friction blocks, the
expansible chamber in the other, the movable friction plate upon the wall of said
chamber adapted by its expansion to be brought into frictional engagement with
the other face of said blocks, means for automatically expanding said chamber so
long as there is relative movement between said shaft and pulley, and means for
collapsing said chamber and separating the frictionally bearing surfaces.
9. In a clutch of the class described, the combination with the fluid circulating
system, of the pump connected therewith, the eccentric for actuating its piston in
one direction, and the spring for actuating it in the reverse direction, said pump
being made up of the cylinder, the cylindrical piston fitted thereto, the sleeve
fitted upon said piston and serving as a seat for said spring, and the packing
interposed between the cylinder and piston, and receiving the thrust of said
sleeve.
10. In a fluid pressure clutch, the combination with the expansible fluid
pressure chamber, of the collapsible hose connected therewith, and serving as a
fluid reservoir.
11. In a clutch of the class described, the combination with the driving and
driven elements, of the fluid circulating system made up of the expansible fluid
pressure chamber and the collapsible fluid reservoir, the interposed pump for
forcing the contents of the reservoir into the chamber, and the relief valve for
permitting the reflow of the contents of the chamber into the reservoir, the
shipping sleeve for throwing the pump into action, the segmental pinion carried by

page_text: the relief valve, the segmental gear operatively engaging said pinion, and the-
flange upon said shipping sleeve for engaging said segmental gear so as to open
and close its connected valve when slipped to throw said pump into or out of
action.
Dated this 5th day of January 1897.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant..