Improvements in Brick-making Machines.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Brick-making Machines.
I, JOHN WILLIAM CRAVEN, of Westgate Common Foundry, Wakefield, in the
County of York, Engineer, do hereby declare the nature of this invention to be as
follows:-
In brick making machines as hitherto arranged the piston by which the moulded
brick is expelled from the mould is in its lowest position when it is beneath the outlet
from the pug mill and consequently clay may drop into the mould and not be properly
amalgamated with the clay forced in from the pug mill and so a defective. brick is
produced. The object of my invention is to overcome this defect and to effect a very
efficient consolidation of the clay whilst it is being forced into the mould. According
to my invention I provide a lever one end of which bears against the stem of the
piston of each mould when it is beneath the outlet from the pug mill, the other end
of the said lever being weighted so that the first named end exerts some considerable
pressure upon the piston which is kept thereby at the upper side of the mould at the
commencement of the filling operation and is gradually depressed as the clay is forced
into the mould so that there is during the filling operation no empty space for
particles of clay to fall into and the clay being forced down into the mould against the
upward pressure exerted on the piston by the lever, the clay is very efficiently
compacted in producing the brick. Towards the end of the filling stroke owing to
increase of friction in the mould it is desirable to lessen the force exerted upon the
piston by the lever. This can he done by weighting the lever by a rolling weight
which will run inwards towards the fulcrum when the piston has been forced down a
certain distance into the mould. A dash-pot may be used to prevent the too rapid
return of the lever when the stems of the pistons pass from over its end.
I, JOHN WILLIAM CRAVEN, of Westgate Common Foundry, Wakefield, in the
County of York, Engineer, 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 :-
In brick making machines as hitherto arranged the piston by which the moulded
brick is expelled from the mould is in its lowest position when it is beneath the
outlet from the pug mill and consequently clay may drop into the mould and not
D 077

page_text: be properly amalgamated with the clay forced in from the pug mill and so a
defective brick is produced. The object of my invention is to overcome this defect
and to effect a very efficient consolidation of the clay whilst it is being forced into
the mould.
According to my invention I provide a lever one end of which bears against the
stem of the piston of each mould when it is beneath the outlet from the pug mill
the other end of the said lever being weighted so that the first named end exerts
some considerable pressure upon the piston which is kept thereby at the upper side
of the mould at the commencement of the filling operation and is gradually depressed
as the clay is forced into the mould so that there is during the filling operation no
empty space for particles of clay to fall into and the clay being forced down into the
mould against the upward pressure exerted on the piston by the lever the clay is very
efficiently compacted in producing the brick. Towards the end of the filling stroke
owing to increase of friction in the mould it is desirable to lessen the force exerted
upon the piston by the lever. This can be done by weighting the lever by a rolling
weight which will run inwards towards the fulcrum when the piston has been forced
down a certain distance into the mould. A dash-pot may be used to prevent the
too rapid return of the lever when the stems of the pistons pass from over its end.
Figures 1 and 2 of the accompanying drawing represent in vertical section and
plan respectively so much of a brick making machine as is necessary to illustrate my
invention. A is the pug mill in which the clay is worked to the necessary
consistency by suitable knives fast on a shaft A¹, on the lower end of which shaft
is a propeller A2 for forcing the clay from the pug mill into moulds. B is the mould
table arranged to rotate intermittently beneath the pug mill, to bring each mould B¹
(of which there may be any desired number) in succession beneath the discharge
passage A³ in the bottom of the pug mill. Each mould is provided with a piston or
plunger B2 having a stem B³ projecting from the lower side of the piston to beneath
the lower surface of the mould table. Beneath the mould table B I provide a lever C
one end c of which lever is situated directly beneath the discharge passage A³ from
the pug mill and on the other end of the said lever is a weight D which tends to
maintain the end c elevated. Each mould as it comes into position to be charged
with clay from the pug mill, has its. piston B2 raised in the mould by an inclined
surface or other suitable means acting on the stem B3 so that the said stem will pass
onto and remain in contact with the end c of the lever C while the clay is being
forced into the mould. As the clay is being forced into the mould the piston B' is
caused to gradually descend in the mould against the counteracting resistance of the
weight D on the lever, so that while the mould is filling, the clay is, by the upward
pressure exerted on the piston by the weighted lever, efficiently compressed. The
weight D is preferably fitted to the lever C so that it can slide or roll there along
as shewn in the drawing, whereby as the end c of the lever is gradually depressed
the weight will move nearer to the fulcrum of the lever, after the piston has been
forced down a certain distance in the mould, and so reduce the pressure exerted by
the lever on the piston. The clay being thus compressed to form a brick a movement
of partial rotation is given to the mould table B to bring the next mould into position
to receive a charge of clay, and during this partial rotation of the mould table 4
the pressure of the piston on the end c being removed the said end will be raised
by weight D into position to engage with the stem of the piston of the said next
mould. The lever is preferably connected to a dash pot E or to an equivalent
arrangement to prevent the too rapid return of the lever when the stems of the
pistons are passed out of contact with the end c of the lever C.
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed, I declare that what
I claim is
1. In a brick making machine the combination with a mould into which clay is
forced from a pug mill, of a piston fitted to slide in the mould, a weighted lever or
its equivalent exerting pressure tending to force the piston in the opposite direction

page_text: to the pressure exerted on the piston by the clay forced into the mould from the pug
mill, whereby the clay is efficiently compacted in producing a brick, substantially as
hereinbefore described.
2. In a brick making machine the combination with a pug mill and a mould table
having moulds provided with pistons; of a lever bearing at one end against the stem
of the piston of each mould when it is beneath the outlet from the pug mill the
other end of the said lever being weighted so that the end which bears against the
stem of the piston will exert considerable pressure on the piston to keep it at the upper
side of the mould at the commencement of the filling operation and so that during
the filling operation there is no space for particles of clay to fall into, and the clay
is forced down into the mould against the upward pressure exerted on the piston by
the weighted lever, substantially as herein before described.
3. In a brick making machine the combination with a pug mill and a mould table
having moulds with inovable pistons, of a lever acting on the pistons to compress the
clay in the mould and a movable weight on the lever by which the pressure of the
piston on the clay in the mould is decreased as the friction in the mould towards
the end of the filling stroke of the piston increases; substantially as hereinbefore
described.
4. The combination with the subject matter of the preceding claims of a dash pot
or equivalent means for the prevention of the too rapid return of the lever when the
stems of the pistons pass out of contact with the lever, substantially as herein before
described.
5. The combination and arrangement of parts constituting the improved means
for compressing clay in the moulds of brick making machines as herein before
described and illustrated by the accompanying drawing.
Dated this 19th day of April 1898.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.