Improvements in Brakes for Pneumatic Tyred Wheels of Cycles.
Year: 1893

page_text: Date of Application. 13th May 1893-Accepted. 17th June. 1893
COMPLETE SPECIFICATION.
Improvements in Brakes for Pneumatic Tyred Wheels of Cycles.
I THOMAS BLACKWOOD MURRAY Bachelor of Science, Electrical Engineer,
Heavyside, Biggar, Lanarkshire 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 improvements in brakes for pneumatic tyred wheels of
cycles, whereby a rubber tyred wheel is brought into contact with and is frictionally
driven by the pneumatic tyre of the wheel to be braked, and to this rubber
tyred wheel a friction brake is applied.
According to my invention the abrasion of the pneumatic tyre consequent upon
applying a friction brake direct to it is prevented by the placing of a rubber tyred
wheel between the pneumatic tyre and the friction brake.
I effect my object by mounting the spindle upon which the aforesaid rubber tyred
wheel runs, on two similar levers the one pair of ends of these levers being pivoted
to the framework of the cycle and the other pair being pivoted to the ends of a
forked link which is in its turn pivoted to the brake lever by means of a con-
necting rod. To this said link is adjustably attached a frictional block brake.
When the brake handle is raised the link is depressed, thereby depressing the ends
of the levers and bringing the rubber tyred wheel into contact with the pneumatic
tyre, and at the same time applying the frictional block brake to the rubber
tyred wheel. The rubber tyred wheel is therefore frictionally driven by the
pneumatic tyre and the necessary retarding force is obtained by the application
of the frictional block-brake to the rubber tyred wheel.
In order that my said invention and the manner of performing or carrying the
same into effect or practice may be properly understood I have appended hereunto
an explanatory sheet of drawings.
Figure I is a side elevation of my improved brake appliance.
Figure II is a front elevation of same.
A is the pneumatic tyre of the wheel to be braked. B is the rubber tyred wheel
running loose on its spindle which is fixed to the two similar levers D D one on
each side of the rubber tyred wheel. The one pair of ends of these levers D. D
are pivoted to the framework of the machine at H Figure 1.
The other pair of ends of the levers D. D are pivoted to the ends of a
forked link L adjustably attached to the connecting rod E which is jointed to the
brake lever F.
G is an arrangement for adjusting the length of the connecting rod E by means
of a screw nut. C is the block brake which is clamped or otherwise adjustably
secured to the link L below the connecting rod E. When the handle of the brake
lever F is raised, the connecting rod E is depressed, thereby depressing the rubber
tyred wheel B and forcing it against or into the pneumatic tyre A. The motion
of the pneumatic tyre A will now therefore be transmitted by friction to the rubber
tyred wheel B. But by the depression of the connecting rod E the block-brake C
is at same time brought into contact with the rubber tyre of the wheel B and thus
produces the necessary retarding force, which is transmitted frictionally from the
rubber tyred wheel B to the pneumatic tyre A.
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 :-
First. The arrangement and construction of the parts of a brake for the wheels

page_text: and adjusting appliances all as herein described in reference to and illustrated by
the accompanying drawings.
Second. The construction and use of a brake for the wheels of cycles consisting
of a rubber tyred wheel, and a frictional block brake applied and actuated all
substantially for the purposes set forth and herein described and illustrated by the
accompanying drawings."
Dated 12th May 1802
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.