Year: 1898

page_text: Date of Application, 17th Dec., 1898
Complete Specification Left, 6th Sept., 1899-Accepted, 2nd Dec., 1899
We, JOHN BUCHANAN THOMSON, Colliery Manager, Fairview, and JOHN SMITH,
Engineer, 154, Eddlewood Buildings, both of Hamilton, in the County of Lanark,
do hereby declare the nature of this invention to be as follows:-
This invention which relates to friction clutches has for its object the provision
of simple and improved means for throwing the driving clutch or coupling into
and out of engagement with the wheel or other part to be driven.
The improved clutch is composed of a disc keyed on the driving or driven shaft
having fitted in proximity to its periphery a ring or band made in two or more
parts so as to permit of its being expanded or contracted in diameter and which
is adapted when expanded to come into frictional engagement with the inner
periphery of a wheel, pulley or flanged disc to which power or motion is to be
communicated or from which motion is to be transmitted to the shaft on which
the clutch disc is keyed.
The expanding and contracting of the clutch ring is effected by means of
toggles or levers whose ends may be of cam like formation and fitted between
enlargements formed on the cut ends of the clutch ring, or which may be other-
wise connected to the ends of the said ring so as by their movement to expand
the ring preferably against the action of springs which may be used to again
contract it when the expanding action is relieved. These levers are by preference
fitted in pairs and at their inner ends are secured screw-threaded nuts into which
the ends of a right and left handed screw spindle fit, so that the rotation of said
spindle may draw together or separate the ends of the levers and cause them to
expand the ring or relieve the expanding action.
On each screw-threaded spindle is fitted a small pinion whose teeth engage
with a worm or spiral thread upon a disc or hand wheel or a worm upon a collar
fitted loose upon the shaft and which worm wheel on being turned by hand effects
the rotation of the pinions and of the screw-threaded spindles whereon the
pinions are fitted so as to operate the clutch actuating levers. Or the hand
wheel may be replaced by a friction wheel with which may be brought into
engagement a second friction wheel actuated by a foot treadle to throw the clutch
into and out of gear.
16L
1000
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank & Fairweather,
Chartered Patent Agents,
62, Saint Vincent Street, Glasgow,
Agent for the Applicants.

page_text: Improvements in Friction Clutches.
We, JOHN BUCHANAN THOMSON, Colliery Manager, Fairview, and JoHN SMITH,
Engineer, 154, Eddlewood Buildings, both of Hamilton, in the County of Lanark,
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 which relates to friction clutches has for its object the provision
of simple and improved means for throwing the driving clutch or coupling into
and out of engagement with the wheel or other part to be driven.
To enable our invention to be clearly understood we will describe it by refer-
ence to the accompanying drawings:-
--
In Sheet No. 1 a is a ring bolted to wheel required to be driven with the
clutch. is the shaft, to which is keyed the disc c. The friction ring in
two parts is made to revolve by the disc e by having the blocks e, e, let in between
the snugs fff f. The friction ring d. runs clear of the ring a when out of gear.
It is put in gear by the levers g 9 g g working round the pins h h (which are
riveted to the disc c) and expanding between the jaws iiii of the friction ring.
These levers are expanded by the right and left hand screws j, j, to which are
keyed the worm wheels k, k. These in their turn are revolved by the spiral cast
on the disc running loose on the shaft and worked by the handwheel m. When
this handwheel is revolved in the opposite direction the friction ring is released
from the ring a and is kept clear of it by the springs n, m, n, n.
It will be observed that the handwheel m revolves with the shaft b whether
the clutch is in or out of gear. By a touch of the hand it is spun round in the
same direction as the shaft is revolving to put the clutch in gear; and to release
the clutch the handwheel m is spun round in the opposite direction until the
friction ring & runs clear of the ring a.
To quicken the speed of applying the clutch, double or treble threads can be
cut on the screws j, j, and it will be observed that by simply reversing these
screws the motion of the hand wheel is also reversed, thus turning it into a right
or left hand clutch when required.
This arrangement can be applied to clutches running at slow speeds up to
twenty revolutions per minute.
Under a modified arrangement of our improvements to work the clutch at
higher speeds we have two separate discs with spiral threads cast on them, one
a left hand spiral and the other a right hand spiral.
Referring to Sheet No. 2 p and q have spirals cast on their faces-one a right
and one a left hand spiral-and they are made to slide along the shaft 6 but are
not allowed to revolve with it, by means of the forked lever r.
To put the clutch in gear the spiral on the disc p is made to engage with the
worm wheels k, k, by means of the forked lever r and held in that position until
the clutch is in gear when it is withdrawn; and to throw the clutch out of gear
the spiral on the disc is made to engage with the worm wheels k, k, and held
in that position until the clutch is out of gear when it is withdrawn.
It will be observed that under this arrangement by simply reversing the order
of putting in the right and left hand spirals cast on the discs บ and the shaft
may revolve in either direction.
9
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is: —
I. Where the clutch is applied to wheels revolving at slow speeds the com-

page_text: bination and arrangement of expanding the friction ring in two parts by levers
fitted between enlargements where the ring is split and made to expand or
contract by right and left hand screws at either ends of spindles to which are
fixed worm wheels, the teeth of which engage with a spiral thread upon a disc
or hand wheel fitted loose upon the shaft, and
II. Where the clutch is applied to wheels revolving at high speeds the same
combination and arrangement of levers, screws and worm wheels, where the worm
wheels are made to revolve by spiral threads cast on discs which slide on the
shaft; all as heretofore described and shewn in the accompanying drawings.
Dated this Fourth day of September 1899.
JNO. B. THOMSON,
JOHN SMITH.