Improvements in Change Speed Gear, especially applicable to Cycles.
Year: 1892

page_text: Date of Application, 30th Dec., 1892
Complete Specification Left, 2nd Oct., 1893-Accepted, 4th Nov., 1893
PROVISIONAL SPECIFICATION.
Improvements in Change Speed Gear, especially applicable to
Cycles.
We, THOMAS BROADBENT of Summer Road, East Molesey in the County of
Surrey, Engineer's Tool Maker, and WILLIAM BROWN of Maidenhead Thicket, in
the County of Berks, Carpenter, do hereby declare the nature of this invention
to be as follows:-
The driving and driven shafts are co-axial and fit inside each other one of
them being hollow and each has a toothed wheel fixed upon it, the wheel on the
driving shaft being larger and having more teeth than the wheel or the driven shaft.
A disc loose upon the outer shaft carries a stud or studs upon which are mounted
a pair or pairs of pinions the pinions of each pair being made in one piece with each
other and gearing respectively with the two toothed wheels.
Means are also provided for connecting the disc to and disconnecting it from the
frame of the machine. When the disc is connected to the frame the driven shaft
revolves faster than the driving shaft since the wheel upon the former is smaller
than the wheel upon the latter and gears with a larger pinion or pinions but when
the disc is disconnected the two shafts are locked together by the pinions and
revolve at the same speed.
Preferably the disc forms one end of a hollow cylinder, the opposite end having
a central hole large enough to pass over the toothed wheels and oil is introduced
into this cylinder to lubricate the gearing, the pinions being almost entirely
immersed when they are at their lowest position.
In order to make an oil tight joint the driven shaft has fixed to it
cylindrical
box just large enough to receive the above mentioned cylinder which takes its inner
bearing on driven shaft.
In this construction the studs may run from end to end of the cylinder and the
pinions may be mounted upon them with ball bearings. There may also be ball
bearings between the driving and driven shafts.
this 20th a
1000
THOMAS BROADBENT.
WILLIAM BROWN.
COMPLETE SPECIFIATION.
Improvements in Change Speed Gear, especially applicable to
Cycles.
We, THOMAS BROADBENT, of Summer Road, East Molesey, in the County of
Surrey, Engineer's Tool Maker, and WILLIAM BROWN, of Maidenhead Thicket,
in the County of Berks, Carpenter, 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 driving and driven shafts are co-axial and fit inside each other one of them
being hollow and each has a toothed wheel fixed upon it, the wheel on the driving
shaft being larger and having more teeth than the wheel on the driven shaft. A
disc loose upon the outer shaft carries a stud or studs upon which are mounted a
pair or pairs of pinions the pinions of each pair being made in one piece with each
other and gearing respectively with the two toothed wheels.
Means are also provided for connecting the disc to and disconnecting it from the

page_text: DRAWING.
Figure 1 is a longitudinal section of the gearing as applied to a bicycle.
Figure 2 is a side elevation looking from the right of Figure 1 some of the parts
being omitted.
Figure 3 is a similar view the cover H of the cylinder G being removed.
A is the driving shaft, A¹ the crank fixed to it and A' A' are the two branches
of the fork carrying the bearings in which it works, these are shown as ordinary
bearings but it will be understood that ball bearings may be employed. B is the
driven shaft forming the hub of the wheel :- -as shown one end is in the form of a
cylindrical box B¹. B are the spokes of the wheel. C is a toothed wheel screwed
and keyed to the shaft A and gearing with the pinions D. Each of the latter is
made in one piece with one of the pinions E which gear with the wheel F screwed
and keyed to the shaft B. The wheels and pinions are all placed inside a cylinder G
closed by a cover H and working inside the cylindrical box B'. I I are spindles
having their left hand ends screwed into the cylinder G their other ends being
received in central holes in the cones J which serve to adjust the rings of balls e
and on which the pinions D and E run. K are combined lock nuts and caps
which secure the cones J and also prevent the escape of oil. a b c and d are
four other rings of balls, a being between the shaft B and the cone L the latter
being screwed on the shaft A and secured in position by the catch L' (Figures 1
and 3) which takes into teeth in its end so that its position can be adjusted. The
balls bare between the cylindrical box B' and the cylinder G, c are between the
wheels C and F and d are between the cone M fixed to the shaft A and the cover H
of the cylinder G.
The means for connecting the cylinder G and disconnecting it from the frame of
this machine are as follows:-N is a bolt sliding ou one branch of the fork A' and
when the cylinder is disconnected its nose N¹ (shown in side elevation at Figure 4)
is clear of the flange H¹ on the cover H, the cylinder G and shaft B being locked
together by the pawl O Figure 3 which being pressed outwards by the spring 01
lies in one or other of the recesses P in the flange of the cylindrical box B'. The
pawl has jointed to it a plate Q (Figure 2) shewn separately in edge view at
Figure 5. When the bolt N is pressed down by the rider by any suitable means
its nose rests upon the flange H until it comes to the opening in the flange H¹ in
which the plate Q lies into which it descends carrying the plate Q down with it
thus simultaneously_locking the cylinder G to the fork A' and lifting the pawl O
out of the recess P so allowing the shaft B to rotate independently of the
cylinder G.
It will be obvious that this gear for changing the speed of rotation in transmitting
the motion from the driving to the driven shaft may in cases where it is not wanted
to ever drive the shafts at the same speed be simplified by permanently fixing
the cylinder G to the frame of the machine as shown in Figures 6 and 7.

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The combination of a driving and a driven shaft, two toothed wheels of
different sizes fixed respectively to the two shafts a disc fixed or capable of being
connected to the frame of the machine and a pair or pairs of pinions mounted on
an axis or axes carried by the disc the pinions of each pair being attached to each
other and being of different sizes so as to gear respectively with the two wheels on
the shafts substantially as described.
2. The combination of a driving and a driven shaft working one within the
other, two toothed wheels of different sizes fixed respectively to the two shafts a
cylinder co-axial with the shafts mounted loosely upon them and fixed or capable
of being connected to the frame of the machine and a pair or pairs of pinions
mounted on an axis or axes fixed longitudinally in the cylinder, the pinions of each
pair being attached to each other and being of different sizes so as to gear
respectively with the two wheels on the shafts substantially as described.
3. Change speed gear substantially as described and shown in the drawings.
1000
THOMAS BROADBENT.
WILLIAM BROWN.
THOMAS BROADBENT.
WILLIAM BROWN.