Improvements in Power Transmitting Gear for Revolving a Shaft or Shafts at a Variable Speed.
Year: 1897

page_text: Date of Application, 3rd Apr., 1897
Improvements in Power Transmitting Gear for Revolving a Shaft
or Shafts at a Variable Speed.
We, JOHN EDWARD THORNTON, of Rokeby, Oldfield Road, Altrincham, in the
County of Chester, Manufacturer, and JAMES POLLARD LEA, of 7, Southbank, Ren-
shaw Street, Altrincham, in the County of Chester, Engineer, do hereby declare the
nature of this invention to be as follows:-
This invention relates to an improved means whereby the power from an engine
or other main shaft may be transmitted to another shaft so as to revolve it at a
speed which may be varied at will within the limits for which the gearing was
designed.
For this purpose the rotation of the said mainshaft is transmitted by suitable
gearing or connections to two shafts lying parallel with each other and revolving
in opposite directions one to the other. At one end or at other suitable position, on
each of these shafts a pulley is fitted having a pneumatic tyre or equivalent device
for the purpose hereafter stated. These pulleys are of equal diameter and engage
with and operate three discs which are mounted at equal distances apart on a
suitable axle or shaft. This axle lies at right angles with the two pulley shafts.
The two outer discs are rigidly attached to the supporting axle so as to form
practically one piece. The other disc lies centrally between the two outer disos.
The axes of the three discs are co-incident but the central disc is free to revolve (and
does in operation) in a direction opposite to the combined outer discs. One of the
two driving pulleys operates between the one outer disc and one face of the central
disc, the other pulley operates between the other outer disc and the other face of
the central disc, and the two pulleys are at all times opposite to each other. By
means of the pneumatic tyres or other equivalent device any suitable degree of
frictional contact may be set up between the two driving pulleys and the three
discs and all strains thus set up are by this arrangement self contained within the
gearing and are not transmitted through the supporting bearings and thus unduė
friction and wear are avoided.
The driving pulleys are so supported and arranged that they may be moved to
and fro across the faces of the discs and accordingly as they are placed near or
otherwise to the centre of the discs so the speed or rate of rotation of the discs is
varied accordingly. The discs are bevelled at their inner or outer edges (or at
both) so that the pulleys may be moved altogether out of contact with the discs,
when the said discs would of course soon cease to revolve.
The power may be taken for final application from the centre disc or from the
combined outer discs as found convenient.
..
0
1000

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Improvements in Power Transmitting Gear for Revolving a Shaft
or Shafts at a Variable Speed.
We, JOHN EDWARD THORNTON, of Rokeby, Oldfield Road, Altrincham, in the
County of Chester, Manufacturer, and JAMES POLLARD LEA, of Worsley Mills,
Hulme, Manchester, in the County of Lancaster, Engineer, late of 7, Southbank,
Renshaw Street, Altrincham, in the County of Chester, 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 improved mechanism whereby the power from the main
shaft of an engine or motor or other driving shaft may be transmitted to another
shaft or mechanism to be rotated at a variable speed to be varied or controlled at
will and is designed to provide friction gear in which all the strains set up are self
contained within the gearing and are not transmitted through the supporting
bearings, whereby undue friction upon and wear of the rotating parts are avoided.
It consists essentially of apparatus constructed with two rotating pulleys or discs
rotating with a primary or driving shaft gearing with two friction discs rigidly
secured to and rotating with a secondary shaft and with a third disc rotating loosely
on the same shaft. It will be fully described with reference to the accompanying
drawings in which as examples three forms or modifications of the invention are
illustrated.
Fig. 1. Plan (partly in section) showing the invention in its simplest form.
Fig. 2. End elevation of same partly in section.
Fig. 3. Plan (partly in section) showing the motion transmitted to two driven
shafts by means of bevel gearing.
Fig. 4. End elevation (partly in section) of Fig. 3.
Fig. 5. Plan (partly in section) showing the motion transmitted to two driven
shafts by frictional gearing.
Fig. 6. End elevation partly in section of Fig. 5.
Fig. 7. Side elevation of same.
The primary or driving shaft A is mounted in suitable bearings carried by a
frame or other convenient support and is geared to a corresponding shaft B by
gear wheels (or by straps) which is caused to rotate in the opposite direction. On
the end of each of the shafts A and B are secured by keys or otherwise a friction
diso or pulley D the two friction discs D also rotating in opposite directions. The
two friction pulleys D engage with the faces of three friction discs EE and F.
The friction discs EE and F are fitted on a secondary shaft G placed at right
angles to the primary shaft A. The two outside discs EE are rigidly secured by
pins e (or other suitable means) to rotate with it and without any movement
thereon and the central or intermediate disc F is free to rotate thereon and is pre-
ferably provided with a sleeve f or with collars to prevent lateral movement..
The rotary movement of the two pulleys or discs D as the shaft A rotates is
transmitted to the discs E E' and F the two discs E E' and with them the shaft G
rotating in one direction and the contral disc F in the reverse direction. The
motion imparted to the discs E E' and F may be transmitted as required either from
the discs E and E¹ or shaft G or from the intermediate disc F as found most
desirable or convenient.
The speed of the discs EE and F and shaft G is increased or diminished as
required by altering the position of the discs D relative to the discs EE' and F
by moving either to and from the other.
The edges of the discs EF and F are bevelled to permit of the discs D being
easily, withdrawn and re-entored between them. The faces of the discs E E' and f

page_text: may be provided with radiating corrugations d or projecting points or the like to
increase the friction or grip of the discs D. The peripheries of the discs D are
provided with pneumatic tyres or bands or with bands of leather or other suitable
friction material.
In the arrangement shown in Figs. 1 and 2 the shafts A and B and the discs D
are moved to and fro as desired by means of the frame C in which they are sup-
ported. The frame is moved in either direction by the screw K. Motion is taken
either from the secondary shaft G by a pulley or wheel 9 placed upon it or from the
periphery of the central disc F by a wheel f¹ engaging with it.
In the arrangement shown in Figs. 3 and 4 the movement of the discs D is
similar to that described with reference to Figs. 1 and 2 and the motion is taken
by two shafts L L' and bevel wheels from the discs E E' and F which are provided
with bevel teeth elf" which gear with the wheels Z.
In the arrangement shown in Figs. 5, 6 and 7 the frame C which carries the
shafts A and B and the discs D is stationary and the shaft G and discs E E and F
are moved to and fro to vary the speed. The motion is taken by two shafts LL'
and friction discs M M which are rotated by contact with the discs E E' and F.
In this arrangement the alteration of the speed is twofold as the discs approach the
periphery of the discs E E and F the latter are driven more slowly and at the same
time the discs M M approach the centre and are also driven more slowly and vice
versa.
The friction gear herein described is specially designed for motor cars and vehicles
but is applicable also for other purposes or mechanism where variations of speed
are required.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what we
claim is:-
1. Friction mechanism for transmitting power constructed with two discs rotating
with a primary or driving shaft gearing with the faces of two discs rigidly secured
to a secondary or driven shaft and with a third intermediate disc rotating loosely
on the same shaft substantially as described.
2. In friction gearing for transmitting power the combination with a primary
driving shaft, a corresponding shaft geared thereto and friction discs rotating
with such shafts of a secondary driven shaft placed at right angles thereto two discs
permanently and rigidly affixed to such shaft and an intermediate disc free to rotate
thereon between which the primary discs may move to and fro and with the faces
of which the peripheries of these discs engage, substantially as described.
3. Friction mechanism for transmitting power constructed substantially as
described and shown with reference either to Figs. 1 and 2, Figs. 3 and 4, or Figs. 5
to 7 of the drawings.
Dated this 30th day of December 1897.