Improvements in or appertaining to the Spring Actuating Mechanism for Shovels or Throwing Devices of Mechanical Stokers, and for other Kindred Mechanism.
Year: 1893

page_text: Date of Application, 21st Jan., 1893
Complete Specification Left, 21st Nov., 1893-Accepted, 30th Dec., 1893
TRUVIDIONAL DI MUSICAL
Improvements in or appertaining to the Spring Actuating
Mechanism for Shovels or Throwing Devices of Mechanical
Stokers, and for other Kindred Mechanism.
We, EDWARD BENNIS and ALFRED WILLIAM BENNIS of Lancashire Stoker
Works, Bolton in the County of Lancaster do hereby declare the nature of this
invention to be as follows:-
This invention consists in an improved mode of actuating the throwing
apparatus in that class of machine firing commonly known as shovel stoking
apparatus.
The usual method by which the shovel is actuated is by the direct action of a
spring and some form of india-rubber or spring buffer.
To prevent the sudden jerk this spring is placed in a very disadvantageous
position, and does not work at right angles to the line of motion, so that a great
deal of power is uselessly expended.
Our improved method consists in an arrangement of spring for throwing and
pneumatic buffer, preferably made as follows:-
A cylinder bored out rather larger for the greater portion of its length is made
at the end away from the shovel arm to fit a piston. This piston is placed on the
end of a rod, which rod is attached to a lever fixed on the shovel arm, or shaft
that actuates the shovel arm as the case may be. Between the piston and the
other end of the cylinder is placed an ordinary spiral spring. Arrangements
are made for increasing or lessening the force of the throw, preferably by a screw
at one end of the cylinder, which puts the spring into more or less compression.
The cylinder is so attached to the apparatus that it can freely rock as the move-
ment of the shovel arm requires it.
The action of the apparatus as follows:-
A cam draws out the shovel arm against the action of the aforesaid spring, which
is thus placed in compression. When the cam releases the shovel arm, the rod
and piston rebound, and, striking the air contained in the air buffer, is without jar
arrested. This arrangement enables us to use a spring and rod at or nearly at
right angles to the movement of the shovel arm, thereby doing the required work
with the least possible expenditure of power and in the most efficient manner.
We may sometimes use a spring in tension instead of in compression, or a volute
or other form of spring can be adapted to this arrangement, though for general
convenience and other reasons we prefer the open spiral spring.
This invention is applicable in all those classes of machinery where a shovel
or like part is actuated by spring propulsion to throw a charge of material or an
article.
1000

page_text: COMPLETE SPECIFICATION.
Improvements in or appertaining to the Spring Actuating
Mechanism for Shovels or Throwing Devices of Mechanical
Stokers, and for other Kindred Mechanism.
We EDWARD BENNIS and 'ALFRED WILLIAM BENNIS, of Lancashire Stoker
Works, Bolton, in the County of Lancaster, 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 :-
t
1 This invention consists in an improved mode of actuating the throwing
apparatus in that class of mechanical stokers commonly known as shovel stoking
machines.
The usual method by which the shovel is actuated is by the direct action of a
spring and some form of india rubber or spring buffer, and in order to prevent a
sudden 'shock to the 'shovel 'on the release of the 'spring, thet spring is placed in
a disadvantageous position, and does not work at right angles to the line of motion,
consequently entailing loss of power.
out
Our improved method of actuating the shovel consists chiefly of a spring
combined with a pneumatic buffer, and is best described by the aid of the
accompanying drawings, in which,
+
Figure 1.is plan of the stoker with hopper shown in 'dotted lines;
Figure 2 is section of the spring and buffer
Figure 3 shows spring, buffer and rod coupled to throwing shovel.
The same letters refer to 'same parts in each figure.
A is the casing or cylinder containing spring B. Cis rod having at one end the
piston D, and at other end the eye E. F is stud on which the spring casing
vibrates and by which it is carried 'on the side of stoker pusher box. G is air
space between piston and end of 'casing, which at this point is bored to receive
piston. His a gland through which rod C works, it is screwed into casing and by
being screwed in or out puts more or less tension on the spring B. I is a pivot
"fixed to stoker box and which carries shovel arm K and shovel L. The cam M
on shaft N is for moving back the shovel arm by engaging with projection or
tappet K. The two latter with the arm or projection C being formed in one
piece, the strains are carried direct instead of through shaft I and key's or
set screws.
I
The action of the apparatus is as follows-
The requisite amount of fuel to be projected into the furnace is fed by suitable
'mechanism in front of the shovel L, said shovel being held back by means of the
projections on cam M (these projections being of different heights to vary the
force of the impact of shovel and so causing an equal distribution of fuel all over
the furnace) as shown by dotted lines in Figure 3. During the time the shovel is
held back, the spring B is in compression, but the cam M revolving lets off the
spring when projection clears tappet K' and the shovel is brought violently into
'contact with the fuel in front of it, 'throwing the same into the furnace. In order
to minimise the shock at the end of the stroke, we provide an air space. which
we describe as the pneumatic buffer in the casing which holds the spring and which
acts in the following manner
t
The piston D slides in the bored part of casing, and as it is moved forward by
the action of the cam M-compressing spring 'B, the movement is sufficiently slow
to allow the air to fill the space between piston and end of casing, a small groove
(not shown in drawing) being cut to allow air to pass. On the release of the
spring, the air is compressed into the space G and forming a buffer, checks the
final movement of the spring and effectually takes off all shock from the apparatus,
which would otherwise cause frequent breakages, and add greatly to the wear
and tear of the apparatus. The force with which the spring acts can be

page_text: adjusted by the gland or nut H, and the position of the point of shovel varied
by the eye E which is formed with a thread to screw on to rod C.
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. In machinery where a shovel stoker or like part is actuated by spring
propulsion to throw a charge of material or an article, the pneumatic buffering
device limiting or controlling the action of the spring toward the end of its
stroke substantially as and for the purposes described: also the method of and
device for adjusting said buffering device.
2. In combination with casing or cylinder A, spring B, piston D and rod C,
a cylinder cover or gland H capable of being screwed any required distance
into the cylinder, whereby the compression or tension on the spring is adjustable.
3. The combination of the spring cylinder A, pivot F, piston rod C and
projection or arm C¹ with the shaft and the shovel arm K and cam tappet K¹,
the latter two formed in one piece with the projection or arm C¹, whereby the
strains are carried direct instead of through shaft I and keys or set screws.
Dated this 20th day of November 1893.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.