Year: 1888

page_text: Date of Application, 13th Nov., 1888
Specification Accepted, 14th Dec., 1888
1. HERBERT JOHN ALLISON, of 52 Chancery Lane, London, in the County of
Middlesex, Patent Agent, do hereby declare the nature of this invention, which
has been communicated to me from abroad by Edward Willson Creacy, of
Washington, District of Columbia, United States of America, Gentleman, and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
The object of the invention is to construct a simple, cheap, and, at the same time,
durable brake-block, one that will be most effective in operation, and which can,
under all circunstances, be brought squarely against the wheel, even though a large
portion of its working-face should be worn away.
This object I attain by the mechanism illustrated in the accompanying drawing, in
which
Figure 1 represents a perspective view of a brake-block embodying my invention.
Figure 2 is a longitudinal sectional view of the same.
Figure 3 is a cross sectional view taken on the line - of Figure 2.
In the drawing,
A indicates a brake-bar or shaft, such as is usually located in the front of the
vehicle's rear wheels, and B a brake-block secured to said shaft and adapted to be
brought into contact with the pheriphey of said wheels in the usual manner.
The shaft A, in the present case, has a threaded nut a¹, and is also provided with
a shoulder or flange C, the lower surface of which is rounded or cain-shaped, for
a purpose as will presently appear.
The brake-blocks of many vehicles, now in use, have been heretofore constructed
of wood, and sometimes the wearing-faces of these blocks are protected by a plate
of metal or shoe; but in either case the wear upon the blocks, when applied to
Leavy road wagons, is such that in a comparatively short time the said blocks
become worn to such an extent as to greatly impair their usefulness, thus rendering
it necessary to replace them with new ones. In the present instance, I have con-
structed the block preferably of cast-iron, the slightly increased cost and weight of
which is more than compensated for by the length of time the block may be used.
LD 7

page_text: At the same time, owing to its shape, the block may be cast with but little trouble
and cost.
The block B has its working-face curved to correspond with the curvature of the
wheel, and is provided on its rear with a loop b, the inner face of which is set back
sufficiently far from the corresponding face of the block as to form a shoulder or
seat D, as shown in Figures 1 and 2, and against which the curved or cam-shaped
portion of the flange (rests. The outer end of the shaft A is passed through the
loop b until the flange is brought against the inner face of said loop, and the nut a¹
screwed upon the threaded end of said shaft until it meets or abuts against the outer
face of the loop, but not with sufficient force to prevent the brake-block from turning
slightly upon its axis.
From this description it is manifest that when the brake-block is brought against
the tire of the wheel it will oscillate upon the shaft, and thus bring its working-
faco squarely against said wheel. By reason of the curved or cam-shaped flange
the block is permitted to oscillate, but only sufficiently to cause it to be brought
directly against the tire of the contiguous wheel.
It is well known that one of the most cominon and annoying results, incident to
many of the blocks as at present constructed, is the liability of the block turning on
its axis sufficiently to throw the block entirely over, thus impairing the working of
the block and necessitating its removal and readjustment. My invention is designed
to overcome this objectionable feature, and, as will be observed, it is accomplished by
the engagement of the block with the cam-flange, which prevents the block, under
any possible circumstances, from rotating in an are greater than what is necessary to
bring the curved face of the block squarely against the periphery of the wheel.
The loop is provided with a set-screw E, or equivalent device, whereby the block
is prevented from slipping off the shaft in the event of the nut a¹, by accident,
becoming detached from the end of the shaft. The upper portion of the shaft, within
the loop, is slightly cut away, as shown at e, to be engaged by the set-screw.
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. The combination with a brako-block, having a shoulder of a shaft or brake-bar
having a flange provided with a cam-surface engaging said shoulder and limiting the
movement of said block, substantially as described.
2. The combination with a metallic brake-block having a loop to receive the end of
the brake-bar or shaft, and a shoulder, of a shaft or brake-bar having a flange
provided with a cam-shaped surface for engaging said shoulder, whereby the
.movement of the block is limited, substantially as specified.
3. An improved brake-block, comprising the metallic block B, the shaft A engaging
said block, and having a flange seated against a shoulder thereon, said flange being
provided with a cam-surface, as described, and means for securing the block against
accidental detachment, substantially as specified.
Dated this 18th day of November 1888.