Improvements in Driving Chains and Chain Wheels.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Driving Chains and Chain Wheels.
JOHN HARRISON, 175, Eastfield Road, Peterborough, Engineer, do hereby
declare the nature of this invention to be as follows: —
An improved method of forming and constructing the parts of driving chains
which come in contact with the wheels and the teeth of the wheels upon which
the chain acts in such a manner so as to prevent any rubbing rolling or scraping
action between the same, thus increasing its efficiency and reducing friction and
wear between the parts of the same.
According to my invention I construct the sides and frame of the chain links
similar to an ordinary roller chain" but in place of rollers I employ angular
shaped pieces of metal or or other suitable material which I mount on the cross
bars of the frame of the links in a similar manner to an ordinary friction roller
but I only allow a limited rotary movement of the same and just sufficient to
allow the part of the angular pieces which lie in between the teeth of the wheels
(when in action) to fall into their place in the wheels freely and without any
rubbing action. The rotary movement of the angular pieces is limited by pro-
jection formed on the angular pieces and which works in or between projections or
slots on the frame of the links.
The teeth of the wheels I form with a straight face and considerably thicker
at the root than at the point thus making the space between the teeth much wider
at the top than at the root of the teeth whilst the pieces which take the place of
the ordinary rollers and which I have described as angular pieces are shaped to
fit in between the teeth when in their working position. The angle of this part
of the angular pieces and the face of the teeth being sufficient to allow the angular
pieces to fall into working position without any scraping or rubbing action and
as soon as they commence to leave the wheel are quite free of the teeth.
Dated this 28th day of July 1898.
Improvements in Driving Chains and Chain Wheels.
I, JOHN HARRISON of 175, Eastfield Road, Peterborough, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement;
-
My invention relates to driving chains and chain wheels and consists in an
improved method of forming and constructing the parts of the chain which come

page_text: in contact with the wheels, and the teeth of the wheels on which the chain acts,
in such a manner as to prevent any rubbing, rolling or scraping action between
the same, thus increasing the efficiency of the gear and reducing friction and
wear between the parts of the same.
In carrying out my invention I construct the sides and frame of the chain links
similar to an ordinary "roller chain," but in place of rollers I employ angular
shaped pieces of metal or other suitable material which I mount on the cross
bars of the frame of the links in a similar manner to an ordinary friction roller,
but I only allow a limited rotary movement of the same, and just sufficient to
allow the part of the angular pieces which lie in between the teeth of the wheels
(when in action) to fall into their place in the wheels freely and without any
rubbing action. The rotary movement of the angular pieces is limited by any suit-
able means, such as projections on the angular pieces which work in or between
projections or slots on the frame of the links.
The teeth of the wheels I form with a straight face and considerably thicker
at the root than at the point thus making the space between the teeth much wider
at the top than at the root of the teeth. The pieces which take the place of the
ordinary rollers, and which I have described as angular pieces, are shaped to fit in
between the teeth when in their working position, the angle of this part of the
angular pieces and the angle between the faces of any two adjacent teeth being
such as to allow the angular pieces to fall into working position without any
scraping or rubbing action, and as soon as they commence to leave the wheel
they are quite free of the teeth.
And in order that my invention may be properly understood I will further
describe the same with the aid of the accompanying drawings, wherein
Figure I is an elevation of a piece of the chain showing one side thereof.
Figure II is a similar view showing the other side.
Figure III is a side elevation of a piece of the chain part of which is in gear
with a suitable sprocket wheel, the chain being in part sectional elevation.
Figure IV is a plan of the chain.
Figure is a side elevation of a sprocket wheel constructed according to my
invention.
Figure VI is a side elevation and Figure VII is a plan showing a modification.
The same numerals refer to the same parts throughout the drawings.
The chain comprises pairs of outer side plates 2 and pairs of inner side plates 3,
the ends of the outer plates overlapping the ends of the inner plates. The pairs
of outer plates are connected to the pairs of inner plates by transverse pins 4.
The ends of the pins 4 are rivetted over and the pins are thereby prevented from
turning in the plates 2. The plates 3 are free to turn on the pins 4 and are
maintained at a suitable distance apart by suitable distance pieces such as collars 5
on the said pins. Or any other suitable construction corresponding to a roller
chain may be employed.
On each pin 4 or its equivalent is mounted an angular piece 6 of approximately
triangular elevation, the apex 7 being directed towards the inner side of the
chain. The bearing faces 8 of the angular pieces are straight and the upper
surface 9 may be of any convenient form.
The teeth 10 of the sprocket wheels 11 on which my improved chain is adapted
to run are also of approximately triangular elevation with straight faces 13. The
angle between the faces of each angular piece 6 is preferably somewhat less than
the angle between the faces of any two adjacent sprocket teeth 10, so that the
impinging faces of the angular piece and tooth may lie in even contact throughout.
In action, as each tooth 10 engages with each angular piece 6, the angular piece
lightly rocks on its pins 4 until the face of the angular piece lies in even contact
with the face of the tooth, and there is no movement between the said angular
piece and tooth while the same are subjected to the driving strain. Directly the
chain commences to leave the wheel the angular piece lifts clear away from the
tooth without any sliding of the face of the one on the face of the other.

page_text: To ensure that each angular piece shall be prepared to properly engage with
the respective teeth of the sprocket wheels as it comes into action, I limit the
rotary movement of the angular piece on its pin. In Figs. I to IV the angular
piece carries a projection 14 and the plates 2, 3 ou one side of the chain are
slotted (15) to receive the projection, the movement of the angular piece being
limited by the respective dimensions of the projections and slots. It will be
observed that the slots 15 enlarge as the chain bends round the sprocket wheels 11,
Or, as shown in Figs. VI and VII, ears 16 may be formed on the side plates 2, 3
and be turned over to engage the ends of the upper surface 9 of the angular
pieces, each ear preferably engaging the ends of two adjacent angular pieces.
In any case the movement of the angular pieces is, to a certain extent at least,
free and independent of the bending of the joints of the chain.
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 I claim
is:-
1. A driving chain having angular pieces mounted on the cross bars or pins
so as to have a limited rotary movement thereon, substantially as and for the
purpose set forth.
2. A driving chain having angular pieces mounted on the cross bars or pins
so as to have a linuted rotary movement thereon, in combination with a chain
wheel having straight faced teeth, substantially as and for the purpose set forth.
3. In driving chains and chain wheels of the kind herein described, making
the angle of the angular pieces less than the angle between any two adjacent
teeth of the chain wheels, for the purpose set forth.
4. In a driving chain of the kind herein described, providing the angular pieces
with projections and the side plates with slots adapted to receive such projections,
substantially as and for the purpose set forth.
5. In a driving chain of the kind herein described, providing the side plates
with cars adapted to engage the upper surfaces of the angular pieces, substantially
as and for the purpose set forth.
ted this 29th day of May 18.
DOUGLAS LEECHMAN, M.Cy.E.J.,
Fellow of the Chartered Institute of Patent Agents,
18, Hertford Street, Coventry,
9, Exchange Chambers, New Street, Birmingham and
75, Chancery Lane, London, W.C., Patent Agent for the Applicant.