Year: 1887

page_text: Date of Application, 25th Feb., 1887
Complete Left, 18th Nov., 1887
Complete Accepted. 20th Dec., 1887
nature of this invention to be as follows:-
This invention relates to that class of apparatus in which there are four friction
surfaces mounted on the same shaft the two middle or inner ones revolving with the
shaft whilst the two outer ones are loose on the shaft and are connected to the parts
to which motion is to be communicated. Either one or other of the inner surfaces
can be pressed against the outer surface nearest to it (one pair of surfaces only being
in contact at the same time) so that whilst the driving shaft continues to revolve the
motion may be communicated at will to either of the two friction surfaces which are
loose on the shaft which is usually done by sliding the two inner surfaces together
bodily along the shaft on which they are mounted until one of them comes in contact
with an outer surface.
Usually the two inner surfaces are the two opposite faces of a single piece or block
so that as they and the outer ones wear away a greater and greater distance has to be
moved through in order to change the motion from one outer surface to the other
whereas it is desirable that this movement should be as small as practicable.
Now according to my invention I make the two inner surfaces adjustable with
respect to one another so that the movement required for changing the motion can be
kept small and constant.
I do this by having them upon separate discs or blocks and by cutting a right
hand screw upon one block and a left hand screw upon the other and by connecting
the two blocks by means of a cylindrical sleeve having corresponding screws cut on
its inner surface. By turning this sleeve the two inner friction surfaces can be made
to approach or recede from each other.
The two inner surfaces are prevented from turning on the shaft by a feather
upon it and it is this feather and not the sleeve which takes the torsional strain.
07

page_text: I prefer where practicable to make the shaft hollow so that the two inner friction
surfaces and the sleeve can be moved to and fro by means of a rod inside it. This
rod has connected to it a transverse key or plate which passes through a slot in the
shaft so that its ends enter and fit a groove around the interior of the cylindrical
sleeve. The advantage of this arrangement is that the wearing of the surfaces does
not affect the adjustment of the gear.
Where it is impracticable to make the shaft hollow I turn a groove on the outside
of the screwed sleeve and traverse the sleeve and with it the adjustable friction
surfaces along the shaft by a clutch fork or other convenient means.
Dated this 25th day of February 1887.
CARPMAEL & Co.,
Agents for the Applicant

page_text: 1, WALTER PITT of Newark Foundry, Bath, Engineer, do hereby declare the
nature of this invention and in what manner the same is to be performed to
he particularly described and ascertained in and by the following statement :-
This invention relates to that class of apparatus in which there are four friction
surfaces mounted on the same shaft the two middle or inner ones revolving with the
shaft whilst the two outer ones are loose on the shaft and are connected to the parts
to which motion is to be communicated. Either one or other of the inner surfaces
can be pressed against the outer surface nearest to it (one pair of surfaces only being
in contact at the same time) so that whilst the driving shaft continues to revolve tho
motion may be communicated at will to either of the two friction surfaces which are
loose on the shaft which is usually done by sliding the two inner surfaces together
bodily along the shaft on which they are mounted until one of them comes in contact
with an outer surface.
Usually the two inner surfaces are the two opposite faces of a single piece or block
so that as they and the outer ones wear away a greater and greater distance has to be
moved through in order to change the motion from one outer surface to the other
whereas it is desirable that this movement should be as small as practicable.
Now according to my invention I make the two inner surfaces adjustable with
respect to one another so that the movement required for changing the motion can be
kept small and constant.
I do this by having them upon separate discs or blocks and by cutting a right hand
screw upon one block and a left hand screw upon the other and by connecting the
two blocks by means of a cylindrical sleeve having corresponding screws cut on its
inner surface. By turning this sleeve the two inner friction surfaces can be made to
approach or recede from each other.
The two inner surfaces are prevented from turning on the shaft by a feather upon
it and it is this feather and not the sleeve which takes the torsional strain.
I prefer where practicable to make the shaft hollow so that the two inner friction
surfaces and the sleeve can be moved to and fro by means of a rod inside it. This rod
has connected to it a transverse key or plate which passes through a slot in the shaft
so that its ends enter and fit a groove around the interior of the cylindrical sleeve.
The advantage of this arrangement is that the wearing of the surfaces does not affect
the adjustment of the gear.
Where it is impracticable to make the shaft hollow I turn a groove on the outside
of the screwed sleeve and traverse the sleeve and with it the adjustable friction
surfaces along the shaft by a clutch fork or other convenient means.
In order that my said invention may be more fully understood and readily carried
into effect I will proceed to describe the drawings hereunto annexed.

page_text: Figure 1 is a transverse section, and
Figure 2 is a longitudinal section of a clutch constructed according to my
invention.
Figure 3 is a view in a plane at right angles to those of Figures 1 and 2 of the
hollow shaft and transverse key.
a, a, and b, b, are the blocks their surfaces where they meet forming the friction
driving surfaces. c is the cylindrical sleeve by which the blocks a, a, are connected
together; it is provided inside with screws corresponding to the right and left hand
screws on the blocks. d is the shaft-the blocks a, a, are prevented from turning
upon it by the feather e. The shaft is made hollow, as shown, and has within it a rod f
which carries at its end the transverse key 9, which passes through a slot in the shaft
and its ends enter a groove on the cylindrical sleeve c.
Figure 4 shows a modified arrangement in which the hollow shaft, with its rod
and transverse key are dispensed with and the clutch is shifted by means of a fork
working in the groove h in the sleeve.
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. A friction clutch in which one pair of the surfaces are made adjustable in
respect to one another, so that the distance through which the clutch is to be moved
when reversing can be kept small and constant, substantially as described.
2. In apparatus such as is claimed under claim 1, providing a feather on the shaft
to take the torsional strain, substantially as described.
3. The apparatus substantially as described and shown in the Figures 1, 2
and 3.
4. The apparatus substantially as described and shown in Figure 4.