Improvements in and connected with Friction Clutches.
Year: 1894

page_text: Date of Application, 26th Oct., 1894-Accepted. 1st Dec., 1894.
COMPLETE SPECIFICATION.
Improvements in and connected with Friction Clutches.
I FREDERICK WILLIAM GOLBY of 36 Chancery Lane, in the County of
Middlesex, Patent Agent, do hereby declare the nature of this invention as
communicated to me by Marius Kastler of 45 Boulevard St. Michel, Paris, France,
Engineer, 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 an improved friction clutch in which the clutching is
effected by wedges which are inserted between the moveable and stationary parts
of the clutch and also to the production of a friction surface for such wedges and
applicable for friction clutches generally.
The invention is represented in the accompanying drawings in which
Figure 1 is a view illustrating the principle of the invention,
Figures 2 and 3 are respectively front elevation and vertical section of a friction
clutch constructed in accordance with this invention and in which the moveable
parts are controlled by a friction plate P and a lever L as will be fully explained
hereinafter. In this form the wedges travel in a plane perpendicular to the
transmission shaft A¹.
Figures 4 and 5 shew front elevation and vertical section of a modified form of
clutch in which the hollow part is conical and the wedges travel in the plane of the
transmission shaft A':
Figure 6 is an enlarged plan and Figure 7 is a section shewing the manner in
which the friction surface is formed.
The essential feature of the invention is the use of wedge shaped blocks which
are pressed between the two parts of the clutch (see Figure 1). But in practice,
the friction of the wedge on the plane surface A being very great, this wedge is
replaced by one or more rigid arms a pivotted each to a fixed axis b which is either
parallel to the transmission shaft A', as shewn in Figures 2 and 3, or is
perpendicular to such shaft as shewn in Figures 4 and 5. These arms a are
furnished with wedge shaped blocks which are forced between the moving and the
stationary parts of the clutch.
In the form shewn in Figures 2 and 3 the principle is the same as in the form
shewn in Figure 1, the only difference being that in the latter, the surface on which
the wedges glide has a very remote centre of circumference, and even to infinity if
the surface is straight, whereas in the former, the centre is comparatively close.
Each fixed axis b (Figures 2 and 3) is placed eccentrically in relation to the axis
of the shaft A¹, the arms a carrying wedge blocks on their extremities. These
blocks may be forced between the two parts of the clutch by the mechanism which
will be now described, or by any other suitable arrangement.
The mechanism for actuating the wedges is composed of an auxiliary friction
plate P which is made to slide longitudinally on the shaft A' by means of the
lever L in such a way as to cause the worms V to rotate in either direction
according to the position of the plate P on the shaft A'. The worins V gear with
the worm wheels R whose axles are screw threaded at their ends in opposite
directions and which engage in threaded apertures in the arms a. By the rotation
of the worm wheels R the closing or opening of the arms a is effected.
To increase the friction the surface of the wedge blocks is covered with any
material whose co-efficient of friction is greater than that of brass or iron, for
example, wood, leather &c. As leather simply fixed on the friction blocks sets up
considerable friction and does not wear out very quickly it has been adopted in the
form of friction surface shewn in Figures 6 & 7. In the friction blocks are formed
cavities into which are introduced strips of leather which are forced together and

page_text: glued one against the other in such a way as to form one laminated block. A
wedge piece or strip of wood, metal or other rigid material is forced between the
laminated block and the side of the cavity and serves to keep the block in
position.
In the modification shewn in Figures 4 & 5 the wedges a instead of moving
around axes parallel to the shaft A' move round axes perpendicular to the said
shaft. To bring the wedges into the clutching position, the arrangement of
mechanism shewn in Figures 4 & 5 is employed. The connected rods m take up,
when the clutch is engaging, the position shewn in the upper part of Figure 5 and
the position shewn in the lower part thereof when the clutch is disengaged. This
type is intended principally for mechanism where little force is available and to
replace the loose or idle pulleys.
The hereinbefore described arrangement of arms having wedge action produces
a pressure and consequently an amount of friction far more considerable than if the
arms were applied normally against the circumference, that is to say, in a radial
manner as in friction clutches of ordinary construction.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. A friction clutch wherein the parts are clutched by wedges inserted between
the moving and stationary parts substantially as described.
2. In a friction clutch wherein the parts are clutched by wedges inserted between
the moving and stationary parts, the means for engaging and disengaging said
wedges comprising an auxiliary friction plate and its adjuncts substantially as
described and shewn in Figures 2 and 3 of the accompanying drawings.
3. A friction surface consisting of leather strips built up into the form of a
laminated block substantially as described, and shewn in Figures 6 and 7 of the
accompanying drawings.
4. A friction clutch constructed substantially as and for the purpose hereinbefore
described and illustrated in the accompanying drawings.
Dated this 26th day of October 1894.
F. W. GOLBY,
36, Chancery Lane, London, W.C.