Year: 1895

page_text: I, FRED TURNBULL of Oswald House Mount Pleasant Spennymoor County of
Durham Draughtsmau do hereby declare the nature of this invention to be as
follows.
-
The object of this invention is to provide an improved form of friction clutch
for the purpose of transmitting rotary motion from one shaft to another, or from a
To
shaft to a belt pulley, spur wheel, 1ope sheave and the like, and vice versa.
provide a fuction clutch which can be used where only a very short length of
shaft is available, and where a small amount of travel is desired for liberating the
surfaces in contact. Or in cases where great power is required to be transinitted
through a comparatively small diameter of clutch. Also to provide means for
adjusting the fiction shoes, or blocks, so as to secure frictional contact at any given
position of the sliding sleeve or to take wear.
up
For this purpose I make use of an ordinary cylinder as used in friction clutches
provided with a boss or hub, to which may be secured a belt pulley, spur wheel or
the like On the inside of this cylinder, 1 place the friction shoes or blooks, and
the mechanism for securing fictional contact between the said shoes and the
cylinder The mechanism consists essentially of a fixed boss, which I call the
driver, having provision for holding the friction shoes. Upon the boss of the diver
is mounted a sliding sleeve on one side of which is pivotted one end of a toggle or
pan of links. The other extremity of the toggle is attached to a cylindrical box
in such a manner that as the sleeve is moved along the boss of the diver, the
cylindeal box 18 moved in a guide projecting from the diver a plane inter-
secting the shaft transseisely. Thus on the sleeve being moved towards the clutch,
the cylindrical box is moved away from the shaft. The opposite ends of the
cy lindrical box are coupled to the friction shoes by other toggles, the friction
shoes being each pivotted at its other extremity to a double eye provided on the
diiver.
Instead of attaching the fictional shoes to a double eye on the driver, I may
make use of two setts of toggle mechanism as described above-one on each and
opposite sides of the shaft and allow the fiction shoes, when being brought in or
out of gear, to slide on a calier projecting from the driver. Or the friction shoes
may be formed or cast in one piece with the driver.
The cylindrical box is provided with the means for adjustment; preferably a
right and a left hand screw, screwed into opposite ends of the cylindrical box, cach
terminating in a single or a double eye.
Dated this Nineteenth day of October 1895.

page_text: TICTION Ciuton.
I, FRED TERNBULL of Oswald House Mount Pleasant Spennymoor County of
Durham Draughtsman 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 :-
The object of this invention is to provide an improved form of friction clutch for
the purpose of transmitung rotany motion from one shaft to another, or from a
shaft to a belt pulley, spur wheel, rope sheave, and the like, or vice versa. Friction
clutches na hitherto constructed have generally been inconvenient on account of the
great amount of 100m required for them to work m along the shaft, and on
account of the travel of the sleeve necessary to bung the fictional surfaces uto
contact.
Means are also provided by this invention for readily adjusting the friction
shoes, or segmental block, so as to secure fictional contact, at any given position
of the sliding sleeve, and taking up any wear on the said shoes
For this purpose I make use of any cylinder o pan, as is used in fiction
clutches provided with a boss or hub to which may be secured, a belt pulley, spur
wheel, and the like; inside of the said cylinder, I place the fiction shoes, or
segmental blocks, and the mechanism, for securing fictional contact between the
said shoes and the cylinder.
Referring to the accompanying diawings :—
Fig. 1 is a transverse section showing the cylinder, friction, shoes, and the
mechanisin for securing frictional contact between the same.
Fig. 2 is a longitudinal section.
Fig. 3 is a plan of the adjusting screws and nut, a part of the clutch driver, and
one sett of toggles.
The piece E, which I shall term the diver, may be keyed to any shaft from
which motion is to be transmitted through the clutch, upon the boss on hub of the
said dive, and capable of longitudinal motion along it, is mounted the sliding
sleeve F, to which is attached a sett of toggles G, G¹, by means of the tuined
pin II, the other ends of the said toggles, which are tinly bored, being made to
encircle the round nut B. Between the outer ends of the toggles G, G', is placed
a D-shaped guide block,, which is for the purpose, in conjunction with the set-
Sciew J, of preventing the nut B fiom rotating whilst the clutch is in use, and also
to act as a guide for the said nut B as it moves towards and away from the hub of
the drive. The guide block is made to fitt & to move freely in a dovetail slot K,
provided in a projection from the diver. Into each end of the nut B 19 screwed
an adjusting sciew L, L' having left-handed and night-handed threads respectively.
I pirler to use these screws for purposes of adjustment only, and not for securing
additional fiction, as is ordimaly done. This adjustment, is effected by
slackening back the set-screw J, from the nut B, and then slightly rotating the
said nut, by means of a spanner or key, applied to either of its polygonal ends, thus
moving the pins M, Mnearer to or further from each other as may be requined',
the set screw J' is then screwed against the nut, and by preference into one of a
series of indentations provided around the sand nut; the point of the set-screw being
formed for this purpose.. The eyes of the adjusting screws M, M' are connected to
the friction shoes N, N' by other two toggles P, P', the remaining ends of the
friction shoes being pivoted to the double eye E of the driver E, by turned
pins It, Rs.
It is obvious, that by moving the sliding sleeve F, along the hub of the driver E
motion is conveyed to the nut B in a direction at right angles to the motion of
the sleeve this motion is in its tuin communicated to the friction shoes by the

page_text: toggles P, P thus bunging the said shoes in contact with or away from the
cylinder S according to the direction in which the sleeve is moved. To secure
the contact of the frictional surfaces, the sleeve F is moved towards the driver, and
when the centre line of the toggles G G is slightly passed the vertical position,
furthur movement of the sleeve is prevented by its coming in contact with a part
of the diver E. The friction shoes N, N' are then in engagement with the
cylinder S, and cannot be liberated until pressure is applied to the sleeve in the
opposite duection.
As the whole of the power necessary for pressing the friction shoes against the
cylinder, is, in this friction clutch, transmitted from the sleeve, solely through
toggle joints, it is evident that less travel of sleeve is required for securing the
clearance between the friction shoes, and the cylinder, than when this power in.
transmitted through screws or levers.
The wheel to which motion is to be transmitted may be secured to the boss S¹ of
the cylinder, which would be bushed with an anti friction metal Or if two shafts
are to be coupled, the cylinder and the diver are each keyed to oue shaft
respectively.
Fig 4 shows a modification of this invention in which the driver and friction
shoes, are formed of one piece of metal, the said shoes being sufficiently elastic to
allow of then being expanded against the cylinder by the toggle airangement.
Fig is another modification in which the fiction shoes N are carried by the
projections E3 on the driver E, instead of the double eye E' shown in Fignies 1
and 2.
The toggle mechanism and adjusting arrangements described, are employed in.
the modifications shown.
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 [
claim is:
(1.) In a friction clutch for the purposes described the combination of two o
more setts of toggle joints capable of movement in planes, at right angles, sub-
stantially as shown & described.
(2) In a friction clutch for the purposes described, the combination, with a
sliding sleeve on the boss of a clutch driver, of the toggle joints substantially as
shown & described.
(3) In a fiction clutch for the purposes described, the combination with two
01 mole setts of toggles, of mechanism for adjusting the friction shoes, substantially
as shown & described.
Dated this 18th day of July 1896.
FRED TURNBULL.