Improvements in or relating to Clutches and Brakes.
Year: 1899

page_text: Improvements in or relating to Clutches and Brakes.
I, ERNEST BURCHELL, M.R.C.S., of 5, Waterloo Place, Brighton, Sussex,
Surgeon, do hereby declare the nature of this invention to be as follows:-
-
My invention relates to clutches and brakes and is specially intended to combine
the advantages of a free wheel and backpedalling on a velocipede, though it will
be obvious that it is capable of numerous other applications.
In carrying out my invention as applied to the hub of a rear driving safety
bicycle I provide the driving gear end of the hub with a circular, toothed rack, and
adjacent to this rack I mount a second toothed rack fixedly on the fork end or
some other suitable non-rotating part of the machine. The chain or other gear
wheel is mounted freely on the end of the hub and is provided with suitable
lateral guides. Pivotted to the said gear wheel are one or more blocks the free
inner edges of which are adapted to engage with the rack on the end of the hub
when forward pedalling or when backpedalling, but the block clears the said
rack when the gear wheel is held stationary. To accomplish this the block is
provided with a spring which holds the sanie normally in an intermediate or
out of action" position; and the block is further provided with a tooth or the
like which is adapted to engage with the fixed or non-rotating rack. This tooth
may be of such a length that when the block engages positively with the rack on
the hub end it, the said tooth, will clear the said fixed rack; or the said tooth may
be pivotted or spring-mounted so that it wipes past the teeth of the fixed rack
when the block is in engagement with the rack on the hub end.
on
the non-
The action of the parts is as follows. So long as the gear ring
remains stationary the block is also held stationary
its pivot by
the above mentioned spring or by its tooth engaging with
rotating rack. On the rider commencing to pedal forward the gear ring
is rotated forward carrying the pivotted end of the block with it, but the tooth
on the block lags behind in engagement with the non-rotating rack. Hence the
forward inner end of the block is forced downwards and so engages with the rack
on the hub end and a positive connection is made by the block between the gear
ring and the hub so that motion is transmitted thence to the road wheel. As soon
as the rider holds his feet stationary the rack on the hub end runs forward under
the block on the gear ring so that, with the assistance of the spring, the block
returns to its intermediate position where it is disengaged from the rack on the
hub end, leaving the hub free to continue its forward rotation independently of
the gear ring. Should the rider desire to check the progress of the machine he
may do so by back pedalling when the rear inner end of the block will be caused
to engage with the rack on the hub end, owing to the tooth on the block lagging
behind in engagement with the non-rotating rack in the direction opposite to
that above described. The gear ring is now in positive connection with the hub
providing for a retarding action through the driving gear. Thus the rider has
positive forward pedalling and positive back pedalling in combination with the
ability to hold the pedals stationary and use them as footrests.

page_text: *
35
And I may adapt the spring to impel the tooth on the block into engagement
with the fixed rack and mount the said fixed rack in such a way that it is
capable of a limited backward rotary movement. On forward pedalling the action
is as before, but on reverse pedalling the fixed rack is turned backwards and
through convenient connections applies a brake of any suitable construction, and
such brake may also be adapted to be applied by the hand or in any well known
manner.
I sometimes proceed as firstly above described but adapt the block to engage with
the rack on the hub end on forward pedalling only, so that the device acts as an
ordinary free wheel.
DOUGLAS LEECHMAN, M.Cy.E.I.,
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.
хирогощение телали со статспes and rаке.
I, ERNEST BURCHELL, M.R.C.S., of 5, Waterloo Place, Brighion, Sussex,
Surgeon, 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:—
My invention relates to clutches and brakes and is specially intended to combine
the advantages of a free wheel and backpedalling on a velocipede, though it will
be obvious that it is capable of numerous other applications.
In order that my invention may be properly understood I will describe the
same with the aid of the accompanying drawings, wherein
Figure I is an end elevation of a bicycle hub fitted with my invention.
Figure II is a similar view when some of the outer parts have been removed.
Figure III is a section on the line III-III in Fig. 1.
Figures IV-XI show the positions certain of the parts assume under different
circumstances.
Figure XII is an end elevation showing a modification by which the rider is
enabled to apply a brake instead of backpedalling.
Figure XIII is a similar view to Fig. 1 showing another modification.
Like numerals refer to like parts throughout the drawings.
Referring to Figs. I-XI, I provide the driving gear end of the hub 2 with
a circular, toothed rack 3, and adjacent to this rack I mount co-axially therewith
a second toothed rack 4 fixedly on the fork end or some other suitable non-
rotating part of the machine. The chain or other gear wheel 5 is mounted freely
on the end of the hub and is provided with suitable lateral guides 6. Pivotted, (13)
directly or indirectly to the wheel 5 is a block 8 the free inner edges 9, 10 of
which are respectively adapted to engage with the rack 3 when forward pedal-
ling or when backpedalling but the block clears the said rack when the gear wheel
is held stationary. It is sometimes more convenient to mount the block on a
separate plate instead of directly on the wheel 5. I have shown this construction
in the drawings, the plate 14 being secured to the wheel 5 by screws 15. It will
be understood that there may be two or more blocks and appurtenant parts, if

page_text: **
desired. The block S is provided with a spring 11 which holds it normally in
the intermediate or out of action" position shown in Fig. II, where it will be
observed the said block clears the teeth of the rack 3. The block is further
provided with a tooth or the like 12 which is adapted to engage with the fixed
rack 4. This tooth is. preferably of such a length that when the block 8 engages
positively with the rack 3 on the hub end it, the said tooth, will clear the said
fixed rack 4; though the said tooth may be pivotted or spring-mounted so that
it wipes past the teeth of the fixed rack when the block is in engagement with
the rack on the hub end, if preferred. The movements of the block are preferably
limited by suitable stops so as to relieve the pivot of unnecessary strain. In the
drawings I have shown the block and tooth sunk in recesses 16, the walls of which
serve as stops. The rack 3 preferably has the teeth set closer than the rack 4.
The action of the part is as follows,-So long as the gear wheel 5 remains
stationary, as in "free wheeling" the block 8 is also held stationary on its
pivot 13 by the spring 11 and/or by the tooth 12 engaging with the non-return
rack 4. On the rider commencing to pedal forward the wheel 5 is rotated forward
carrying the pivotted end of the block 8 with it, but the tooth 12 lags behind in
engagement with the non-rotating rack 4 (Fig. IV). Hence the edge 10 of the
block is forced downwards and so engages with the rack 3 on the hub end (Fig. V).
Further movement of the wheel 5 in the same direction causes the edge 10 of the
block to bed right down into the rack 3 (Fig. VI) and positive connection is thus
made by the block S between the gear wheel 5 and the hub 2, so that motion
is transmitted thence to the road wheel. Thus further movement of the block
turns the tooth 12 up clear of the rack 4 (Fig. VII) and so prevents clicking in
driving.
As soon as the rider holds his feet stationary the rack 3 on the hub rotates
forward under the block which, under the actions of the spring returns to its inter-
mediate position (Fig. II) where it is disengaged from the rack 3 leaving the hub
free to continue its forward rotation independently of the gear ring. The said
spring 11 also gives the tooth 12 a certain amount of liberty in re-engaging with
the rack 4.
Should the rider desire to check the progress of the machine he may do so
by back-pedalling when the rear edge 9 of the block 8 will be caused to engage
with the rack 3 on the hub (Figs. VIII and IX) owing to the tooth 12 lagging
behind in engagement with the non-rotating rack 4 (Figs. X and XI) in the direc-
tion opposite to that above described. The gear wheel 5 being thus brought into
positive connection with the hub provides for a retarding action through the
driving gear. Thus the rider has positive forward pedalling and positive back
pedalling in combination with the ability to hold the pedals stationary and use
them as footrests.
I sometimes proceed as above described cut remove the edge 9 so that the block
will engage with the rack 3 on the hub on forward pedalling only, and the device
thus acts as an ordinary free wheel.
According to the modification shown in Fig. XII I adapt the spring 11 to impel
the tooth 12 on the block 8 into engagement with the rack 4 but mount the said
rack in such a way that it is capable of a limited backward rotary movement. For
example, it may be loose on the wheel axle 18 and be furnished with a stud 19
adapted to engage the fork end 20 with which it is normally held in contact by
a suitable spring, such as 21 which tends to rotate the said "rack forwards. The
block and tooth are prevented from turning forward as by limiting the recesses 16
in that direction. On forward pedalling the action is as before, but on reverse
pedalling the rack 4 is turned backwards and through any convenient connections,
such as the rod 22 jointed thereto, applies a brake of any suitable construction,
and such brake may also be adapted to be applied by the hand or in any other
well known manner.
Various other modifications and applications may be made without exceeding
the fair scope of my invention. For example, as shown in Fig. XIII, a friction

page_text: grip may be substituted for the positive grip of the block and rack shown in the
other figures. The part 3 is provided with a plain surface, and the parts 9 and 10
of the block 8 are shaped so as to jam against the said surface ou driving or back-
pedalling.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. A clutch device providing a forward drive, a backward drive and an inter-
mediate disconnection, constructed, arranged and adapted to operate substantially
as set forth.
2. A clutch and brake device providing a forward drive, a brake actuation and
an intermediate disconnection, constructed, arranged and adapted to operate
substantially as set forth.
3. A clutch device comprising a driving part, a driven part, a rack or other
friction surface on the driven part, a fixed rack, a block and tooth pivoited on
the driving part and a spring tending to hold said block and tooth in an inter-
mediate position, the tooth being adapted to engage with the rack so as to throw
the block into engagement with the friction surface on forward or rearward, or
both forward and rearward, rotation of the driving part, and the said block being
disengaged from the said friction surface at an intermediate position, for the
purpose set forth.
4. The modified construction in which the block engages with the friction
surface when the driven part is rotated in one direction but not in the other.
5. A clutch and brake device comprising a driving part, a driven part, a rack or
other friction surface on the driven part, a rack adapted to rotate in one direc-
tion against the action of a spring which normally holds it up to a stop in the
other direction, a block and tooth pivotted on the driving part and a spring tending
to hold on the said block and tooth in an intermediate position, the tooth being
adapted to engage with the rack so as to throw the block into engagement with
the friction surface on rotation of the driving part in one direction, and to rotate
the said rack and apply a brake on rotation of the said driving part in the opposite
direction, the said block being disengaged from the said friction surface at an
intermediate position, for the purpose set forth.
6. A clutch device constructed substantially as herein described with reference
to Figs. I to XI of the accompanying drawings.
7. A clutch and brake device constructed substantially as herein described with
reference to Fig. XII of the accompanying drawings.
8. A clutch device constructed substantially as herein described with reference
to Fig. XIII of the accompanying drawings.
Loted this 9th dor of July 1900
DOUGLAS LEECHMAN, M.Cy.E.I.,
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.