Year: 1897

page_text: Adjusta
ROBERT FOSTER RIMMINGTON, 40, Dornton Road, Balham, S.W., Engineer,
Mechanical, do hereby declare the nature of this invention to be as follows:-
An arrangement in which the gear wheels are built up in pieces so that the
periphery of the wheel can be increased so as to increase the pitch of the teeth.
The rim or periphery of the wheel forming the teeth is divided radially into any
suitable number of loose parts. The circle or rim of such loose parts being
supported on their inner circumference by a part of the wheel through which the
axle passes, having also an abutment on one or each side of the loose parts of the
rim or periphery to which abutment or abutments the loose parts may be held
by bolts or screws. For one abutment a loose ring or side plate may be sub-
stituted.
The bolts or screws which hold the loose teeth or parts of the rim, circle or
periphery to the abutment or abutments are each fitted with a cam or excentric
sleeve or bush in the hole in each loose part of the rim, circle or periphery thro'
which the bolt or screw passes. On the cam or excentric sleeve or bush being
rotated about each bolt or screw as a centre by suitable means, the loose parts
of the rim, circle or periphery through which it passes may be placed at an
increased distance from the centre of the wheel thus increasing the pitch of the
teeth.
A thin corrugated circular spring or a thin plain ring of suitable material
may be used to pack up the loose parts of the rim, circle or periphery when these
are moved out from the centre of the wheel.
1007
I. ROBERT FOSTER RIMMINGTON, of Dornton Side, 40, Dornton Road, Balham,
S.W., Engineer, do hereby declare the nature of this invention & in what manner
the same is to be performed, to be particularly described & ascertained in & by
the following statement:-
This invention relates to sprocket or chain wheels-the object being to provide
a sprocket or chain wheel capable of being altered or adjusted with respect to its

page_text: diameter or "pitch" so that when any stretch or increase in the length of the
chain (alteration of the pitch) takes place thereupon the chain wheel can be
correspondingly enlarged in diameter or adjusted as desired.
According to my present invention I arrange & mount the periphery of the
wheel carrying the sprocket teeth or construct such periphery in parts carrying 5
the sprocket teeth in suchwise that said teeth can all be moved radially from or
towards the centre of said wheel & furthermore I provide means by which said
periphery or the several parts thereof can be firmly & securely locked in any
desired manner & in any desired position.
In carrying out my present invention the rim or periphery of the wheel carrying 1
the teeth thereof is divided radially into a suitable number of separate parts
advantageously of a truncated sector-like form the circle of such separate parts
being separated on their inner circumference by a part of the wheel through which
the axle passes & having an abutment or flange on one or each side of said sectors
or parts to which abutment or abutments the said sectors or parts may be held 1
by bolts or screws or other suitable means.
Or for one abutment or flange a loose ring or removable side plate may be
substituted.
The bolts or screws which hold the sectors or separate parts of the rim or
periphery each pass through a hole in or are otherwise suitably attached to a 2
cam or eccentric sleeve or bush operating in a hole in each said sector or separate
part or other equivalent means may be employed by which to maintain in position
each said sector or part.
Upon the cam or eccentric sleeve or bush being partially rotated or turned by
a key or other suitable means each said sector or separate part of the rim is 2
thereby placed at an increased (or decreased) distance from the centre of the
wheel.
When, the pitch of the wheel is increased i.e. when the sectors or separate parts
have been expanded a thin corrugated circular spring or thin plate or any suitable
material or other suitable packing may be inserted between the inner ends of 3
said sectors or separate parts & the hub or nave of the wheel.
And in order that my present invention may be easily understood & readily
carried into practice I will proceed to further describe same with reference to the
drawings hereunto annexed.
Fig. 1 is a view (partly in section) of an adjustable pitch chain wheel before
same is expanded according to the present invention.
Fig. 2 is a cross-sectional view on the line 2-2 Fig. 1.
Fig. 3 is similar view to Fig. 1 but showing the sectors or separate parts
expanded.
Fig. 4 is a view of one of the sectors or separate parts removed from the wheel. 4
Fig. 5 is an end view of the eccentric bush or lining for insertion in the hole 6³
in said sector.
Fig. 6 is longitudinal vertical section of Fig. 5.
Fig. 7 is a side view of the screw or bolt d which passes through the abutments
& through the intervening sector.
a is the hub or nave through which the axle passes & having two abutments or
flanges a¹ a² thereon or said 2nd flange a³ may be a removable ring.
bb are the separate parts forming the periphery such separate parts in the case
illustrated being shown as truncated sectors adapted when in their innermost
position (as shown in Fig. 1) to fit snugly at their inner circumference 61 against
the exterior of the hub a while on their radial sides i.e. on their adjoining faces 62
Fame fit snugly & compactly together all as shown in Fig. 1 thus making a
practically solid ring.
Each sector ben the outside edge thereof has formed arranged or mounted a
tooth & all these said sectors with teeth thereon being counterparts & inter-
changeable.
is the eccentric sleeve or bush provided with a cross cut or indentation c* in
4

page_text: the end thereof (see Figs. 5 & 6) said cam or bush c being adapted to fit more or
less accurately the aperture 63 in the sector b.
d is screw or bolt which passes through the bush e in said sector 6 & is screwed
into the flange a¹ see Fig. 2.
To adjust this chain wheel i.e. to alter the pitch thereof for instance from that
shown in Fig. 1 to that shown in Fig. 2 the screws d are withdrawn & the flange a²
removed (or when both flanges a¹ & a² are fixed then the sectors b are withdrawn
from between said flanges) & then the eccentric sleeve or bush c in each sector b
respectively can be turned the same amount so that all said sectors are concentric
& then when the screws d have been again tightened up (after the packing e has been
inserted, see Fig. 3) thereby the increased pitch of the wheel has been obtained.
It will thus be seen that any required degree of adjustment can be obtained of
course limited by & depending on the size or form of the eccentric bushes or
linings c in said sectors b.
Having now particularly described & ascertained the nature of my said
invention & in what manner the same is to be performed, I declare that what
I claim is:-
1. An adjustable pitch chain wheel having the periphery or part carrying the
teeth of said sprocket wheel formed of a number of separate parts or sectors &
means to radially adjust said sectors or parts carrying the sprocket teeth & fix
& hold same in a concentric ring at varying distances from the centre substantially
as & for the purposes hereinbefore described.
2. An adjustable pitch chain wheel consisting of a hub such as a with
flanges a¹ a thereon, sector-like devices such as 6 carrying the sprocket teeth 1
thereon & arranged in a circle around said wheel & between said flanges, an
opening in each said sector, an eccentric bush or lining such as c in each said
opening & adapted to be revolved therein, a bolt or screw such as d adapted to be
passed through each said eccentric bush or lining & means to revolve each said
eccentric bush or lining to thereby alter the pitch of the chain substantially as
& for the purposes. herein before set forth.
3. An adjustable pitch chain wheel the several parts of which are constructed
combined & arranged to operate substantially in the manner & for the purposes
herein before described with reference to the drawings hereunto annexed & as
illustrated in said drawings
this 3rd day of September 1898.
TONGUE & BIRKBECK,
31, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.