Improvements in Brakes for Tramcars and analogous objects.
Year: 1892

page_text: Date of Application, 13th Apr., 1892
Complete Specification Left, 13th Feb., 1893-Accepted, 18th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in Brakes for Tramcars and analogous objects.
We, WALTER THOMSON, Grocer, of Melrose House, Whitley in the County of
Northumberland, JAMES THOMSON, Fitter, of 49 Walton Street and WILLIAM
JOHNSTON THOMSON, Grocer, of 7 Haydon Street, both in Gateshead in the
County of Durham do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in brakes for tramcars and analogous
objects and is intended to supplement the ordinary hand power brakes now generally.
in use.
For instance a conductor brakesman or guard usually has to turn a screw handle
which by means of cranks and bars causes the brake blocks to recede from or
approach the wheel tires or braking surfaces.
On steep gradients and in analogous cases such an appliance frequently fails and
it is in the event of such failure that our invention is specially applicable.
Our improvements are semi-automatic in action.
A hand lever may be moved and the vehicle or analogous object accomplishes
the rest automatically.
The mechanism constituting the essential portion of our invention consists in the
provision on an axle or shaft of a scroll or worm working in connection with a rod
which is connected to and designed to actuate a double or multiple armed crank or
lever fitted on the vehicle or other frame. To these arms slotted links or their
equivalent may be connected and attached by other levers to the crossbar on which
are the cranks which operate the rods fitted to the brake segments.
A hinged and if necessarily weighted guide piece is further provided in connection
with the rod which gears with the scroll or worm aforesaid and this guide piece is
capable of being raised or lowered so as to put the rod out of or into gear with the
scroll or worm at will.
In the case of a runaway vehicle and in analogous cases the throwing into gear
with the scroll or worm on the axle or shaft of the rod aforesaid immediately causes
the latter to be drawn to one side according to the direction of travel of the vehicle
or axle which has the effect through the medium of the mechanism above described
or the equivalent thereof of automatically putting on the brake with very great
power. The scroll may if desired have a gradually increasing diameter in either
direction from the centre. A suitable working surface is provided on the rod to
gear with the convolutions of the scroll worm or screw. The invention is obviously
applicable for braking vehicles drums discs and similar objects.
This tot 1.
A 1900
A. CRAW HALL CHAPMAN,
3, St. Nicholas Buildings, Newcastle-on-Tyne, Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Brakes for Tramcars and analogous objects.
We WALTER THOMSON, Grocer, of Melrose House, Whitley, in the County of
Northumberland, JAMES THOMSON, Fitter of 49 Walton Street and WILLIAM
JOHNSTON THOMSON, Grocer, of 7 Haydon Street, both in Gateshead, in the
County of Durham do hereby declare the nature of this invention and in what

page_text: 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 tramcars and analogous
objects and is intended to supplement the ordinary hand power brakes now generally
in use.
For instance a conductor brakesman or guard usually has to turn a screw handle
which by means of cranks and bars causes the brake blocks to recede from or
approach the wheel tires or braking surfaces.
On steep gradients and in analogous cases such an appliance frequently fails & it
is in the event of such failure that our invention is specially applicable. Our
improvements are semi-automatic in action. A hand lever may be moved & the
vehicle or analogous object accomplishes the rest automatically.
The mechanism constituting the essential portion of our invention consists in the
provision on an axle or shaft of a scroll or worm working in connection with a rod
which is provided with a suitable working surface to gear with the convolutions of
the scroll, worm or screw. The rod communicates its motions to levers which may
be arranged in a great variety of manners in order to effect the braking of the
vehicle.
which
We will describe our apparatus with reference to the accompanying drawings in
Figure 1 shows very clearly in plan view one method of practically performing
our invention & in the following description like marks of reference indicate like
parts.
Referring to the drawing a is the axle of a wagon tramcar railway or other
vehicle. On the axle is mounted a worm 2 of suitable diameter with which a rod 6
having a suitable working surface, in the form of a toothed sector 3, gears. The
rod may be supported in a bearing at 4 the bracket for this being secured to
the underside of the vehicle framing.
Across the underside of the vehicle & carried or supported in brackets at its ends
is placed a beam 5 which is designed to carry the opposite end of rod 6. This end
of the rod is caused to actuate the double-armed lever 7. In the drawing the rod 6
is shown fitted into & working loosely in a recess or guide piece in the centre of the
arm 7; the detail of this is shown in Fig. 2 which is a section on line y in Fig. 1.
Thus any lateral or radial motion of this end of the rod 6 is transmitted to the arms 7
80 as to make them rock or radiate slightly their radial path being indicated in dotted
lines in the drawing. The ends of arms 7 are connected to tension rods 8 and 8*
having slotted ends as shown; these rods are also connected to cross-beams 9 to the
ends of which are secured the brake segment blocks 10. It is obvious that if the
worm aforesaid is in gear with the sector (it is shown out of gear in the drawing)
the revolution of the axle in either direction will pull over the sector either to the
right or left and in doing so the opposite end of rod 6 will be pulled over which
will canse arms 7 to move as described and in whichever direction these arms move
they will tighten up either the two rods 8 or the two rods 8"; in this manner the
beams 9 are drawn inwards to apply the brakes to the wheels W. Thus if the
sector is moved by the revolution of the axle towards r¹ then the rod 6 must move
so as to cause the arms 7 to tighten rods 8" 8* & in this manner the beams 9 will be
drawn inwards to act on the brake blocks as just described. In throwing the sector
in and out of gear with the worm it is obvious that a variety of devices may be
employed. In the drawing a vertical spindle S is shown. The upper end of this
spindle is designed to be fitted with a hand wheel or lever by which the conductor
or guard can put into or out of gear the brake. The lower end of the spindle may
pass through a slot 6* in rod 6 and through the two-armed lever 7 to rest in a step
in the crossbeam 5. It will be observed that the lever 7 with its recess or guide
piece in which the end of rod 6 works is centred or hinged at S. Opposite the slot
in the rod 6 & on the spindle S a cam or eccentric C is forged or secured so that
the turning of the spindle by the hand wheel aforesaid causes the cam to act on the

page_text: sides of the slot to push forward or backward the rod & sector into or out of gear
with the worm as required.
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 with a tramcar or other axle having a scroll or worm thereon
of a rod having a suitable working surface, such as a toothed sector, thereon the
worm or scroll and rod and sector being designed when in gear with one another to
apply by means of crossbars and rods the brake segment or other brake blocks
to the wheels substantially as and for the purposes herein set forth.
2. The improved combination or arrangement of parts whereby the turning of a
handwheel or lever puts into gear with the convolutions of a worm or scroll on the
axle a rod which is then actuated by the revolutions of the axle to automatically
apply the brake blocks to the wheel tyres substantially as herein set forth.
Dated this 11th day of February 1893.
A. CRAWHALL CHAPMAN,
3, St. Nicholas Buildings, Newcastle-on-Tyne, Patent Agent.