Improved Machinery for Making Slabs, with Plain or Ornamented Surfaces of Plaster, Cement, or Composition.
Year: 1899

page_text: Date of Application, 21st Feb., 1899
Complete Specification Left, 20th Dec., 1899-Accepted, 17th Feb., 1900
Improved Machinery for Making Slabs, with Plain or Ornamented
Surfaces of Plaster, Cement, or Composition.
GEORGE BERRINGER HALL, of "Valkyrie," Colney Hatch Lane, Muswell Hill,
London, N., Surveyor, do hereby declare the nature of this invention to be as
follows:-
My invention relates to apparatus for making slabs, plain or ornamental of
plaster, cement or composition for use in constructing walls, ceilings, roofs,
dampcourses, paving and other purposes from plastic material delivered in a
continuous stream on an endless travelling band and compressed between one
or two pairs of rollers with or without rubber surfaces which may be plain
flatted fluted or ornamented, and then cut into the lengths required.
The process consists of feeding, mixing rolling, cutting and keying and con-
veying away.
The feeder is fixed on the upper floor, and consists of an endless
belt or chain for each ingredient used; attached is a continuous channel formed
of boxes, the ends of which may be closed or open, and is filled by passing under
a hopper, the surplus being removed by a shutter which strikes the top edge as
it proceeds, and then delivers its contents to the hopper over the mixer. The
feeding is controlled by the attendant on the lower floor by turning a wheel or
wheels to increase or decrease the quantity of any one or all of the ingredients,
the said wheel works a screw which guides the band along cone pulleys. The
mixer is a trough fitted with two screw conveyors, so constructed that the teeth
almost touch the rounded bottom as they revolve, in this the ingredients are
mixed while a sufficient spray of water or other liquid is directed on the mass
from a T sprayer incorporating and consolidating the material and extending
it in a uniform and continuous stream from a slit like orifice on to the travelling
band formed of canvas, wire netting, vulcanized rubber or the like, this band
is at least as wide as the slabs to be made and is so arranged that it moves hori-
zontally over rollers at either end beside the roller or rollers which compress
the material forming the slab and in addition is driven by being made to pass
over and under three rollers fitted below and geared to the rolling machine. The
rolling machine consists of one or two pairs of rollers through which the material
passes on the band above described and the slabs may be covered on one or both
sides with paper canvas or other material which is fed from rollers fitted above
or below the machine.
The cutter. As the plastic material emerges from the compressing rollers a
revolving cutting roller geared to the machine cuts the slabs to the required length
by a guillotine knife hidden in the roller till at right angles to the slab when
it suddenly descends cuts and returns.
The keyer. As the slab begins to leave the table it is keyed either by a comb

page_text: composed of a bar of metal having sharp steel teeth at convenient distances and
having a slight side motion while the teeth forms the necessary key as the slab
passes along, or it may be formed by gearing to the end roller where the slab
comes off the table, another, fitted with steel wires so fixed that it scratches the
slab sufficiently to form a key while it being given a slight side motion all lines
of weakness are avoided in the slab, geared to this is a roller wire brush to clean
the teeth of the keying roller.
The finished slab is then placed on endless wire ropes running on-an even
surface and conveyed away to a convenient place for drying.
Improved Machinery for Making Slabs, with Plain or Ornamented
Surfaces of Plaster, Cement, or Composition.
I, GEORGE BERRINGER HALL, of "Valkyrie," Colney Hatch Lane, Muswell Hill,
London, N., Surveyor, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement: -
My invention relates to that class of apparatus designed for producing slabs,
plain or ornamental, of plaster, cement, or composition for use in constructing
walls, ceilings, roofs, damp courses, paving or for, other purposes, from plastic
material delivered in a continuous stream on an endless travelling band and
compressed between a pair or pairs of rollers having plain, flatted, fluted. or
figured surfaces, the continuous slab thus produced being afterwards divided into
the lengths required.
Such apparatus was described in the Specification of Letters Patent dated
18th January 1895 No. 1256, and is designed to effect the operations of mixing
the ingredients and delivering the plastic material to a rolling machine; com-
pressing said material between rollers so as to produce a continuous sheet, and
dividing said sheet into the required lengths; and the present invention con-
sists in providing such apparatus with means for enabling the relative proportions
of the ingredients to be varied as required, and with means whereby one side of
the slab is keyed"; the invention also comprising certain modifications of
the rolling and cutting apparatus whereby better results are obtained than
heretofore.
The invention will be described with reference to the accompanying drawings
forming part of this specification wherein Figure 1 is a side elevation of the
apparatus (partly in section) a portion of the rolling and cutting table being
broken away. Figure 2 is a plan view shewing the mixer and the rolling and
cutting apparatus with their driving gear. Figure 3 is a plan view of the
apparatus for feeding the ingredients to the mixer, and of the mechanism
whereby the relative proportions of said ingredients may be varied. Figures 4
and 5 are respectively cross and longitudinal vertical sections of one arrange-
ment of the slab cutting device, and Figures 6 and 7 are respectively cross and
horizontal sections of another arrangement of the same device.
According to my invention the dry ingredients of the plastic material of which
the slabs are to be formed are thrown in bulk into separate overhead bins or
hoppers 1, 2, having discharge apertures 3, 4 (which may be controlled by

page_text: sliding doors or shutters, not shewn) delivering respectively into conveyers 5, 6,
by means of which said ingredients are introduced separately into the mixer.
These conveyers may be of any convenient type of construction but are preferably
formed each of a continuous series of buckets 7 attached to an endless chain
or band 8 stretched upon a pair of sprocket wheels or pulleys 9, 10, mounted
respectively on horizontal shafts 11, 12. One of the pulleys (9 in the drawings)
being caused to rotate, the buckets 7 pass in succession beneath the delivery
aperture of the corresponding hopper 1 or 2, receiving therefrom the material,
and upon being inverted by passing around the pulley 10, discharging the
material into a shoot 13 leading to the mixer.
The mixer 14 consists of a long trough wherein two shafts 15, 16, mounted
longitudinally side by side and carrying each a series of inclined blades or
pallets 17 are caused to rotate in opposite directions, the bottom of the trough
having a slight downward inclination from the end at which the shoot 13 delivers
the ingredients to the mixer, to the discharge outlet 18 formed in the bottom of
the trough immediately above the rear end of the rolling and cutting table.
Water is sprayed on to the contents of the mixer from a pipe 19 terminating
in a rose sprinkler 20 so situated relatively to the length of the trough that the
dry ingredients are thoroughly mixed before being wetted. The inclination of
the blades 17 is such as to co-act with the downward inclination of the bottom
of the trough in causing a continuous forward movement of the material in
the mixer, so that the ingredients delivered by the shoot 13, after being
thoroughly incorporated with one another and formed into a plastic mass with .
water, are discharged in a continuous uniform stream from the outlet 18.
Means are provided whereby the relative proportions of the ingredients
delivered by the conveyers 5, 6 may be varied at will whilst the apparatus is at
work, said means consisting of a pair of oppositely coned belt drums 21, 22,
interposed in the driving gear of each conveyer, the fork 23 which determines
the position of the driving belt 24 upon the two drums, being mounted on a
nut 25 working on a leading screw 26 rotated through suitable gearing by a hand
wheel 27 placed in convenient proximity to the rear end of the rolling and
cutting table, the rotation of the hand wheel in either direction causing a corre-
sponding movement of translation of the fork 23 and consequently of the belt 24
longitudinally of the coned drums 21, 22, so that the speed of each conveyer
and therefore the quantity of material delivered by it, may be regulated with
great exactness. The two hand wheels 27 respectively pertaining to the two
conveyers 5, 6, as well as the hand wheel 28 controlling the stop valve on the
water supply pipe 19, are mounted alongside of one another, so that the attendant
supervising the rolling operation is enabled to control with ease the composition
of the mass of material passed through the rolls.
It will be obvious that in some cases more than two bins or hoppers such
as 1, 2, and conveyers such as 5, 6, may be needed, according to the number of
ingredients which go to form the material of which the slabs are composed;
but the arrangement illustrated and described above will suffice for ordinary
cases such as that of slabs formed of fibrous plaster, the one hopper being used
for plaster of Paris and the other for hair or other fibre.
The apparatus by which the plastic material is rolled into a continuous sheet
comprises a long horizontal table 29 beneath an aperture in which, a transverse
metal roller 30 is mounted to rotate, the top of the roller, being flush with that
of the table. A second metal roller 31 of the same diameter and width as the
other is mounted parallel to and directly over roller 30, the two rollers being
geared together so as to rotate with the same surface speed, and the distance
between the rollers being capable of being varied (for the purpose of regulating
the thickness of sheet produced) by raising or lowering the upper roller 31
whose gudgeons 32 are for this purpose journalled in bushes 33 adjustable by
means of screws 34 in vertical guides 35 in the side frames 36 of the machine.
These rollers 30, 31 may if desired be clothed with india-rubber.

page_text: Upon the top of the table 29 is stretched the upper portion of an endless
travelling band 37 of the same width as the rollers 30, 31, the band passing
between these and over a horizontally adjustable roller 38 at the rear end of the
table and another roller 39 at the opposite end, returning around three rollers 40,
41, 42 mounted in bearings in the lower part of the frame. The band 37 is also
maintained in driving contact with the lower portion of roller 30 so as to be
caused to travel and to continuously carry the plastic material, delivered on to
the band, between the rollers 30, 31 and onwards past the measuring and cutting
and keying mechanisms to the delivery end of the apparatus; the band being
maintained at the proper tension by the horizontal adjustment of roller 38 and
vertical adjustment of the middle roller 41 of the three lower rollers 40, 41, 42,
the roller 41 being if desired positively driven so as to communicate motion to
the band. The material of which the endless band 37 is composed is preferably
strong rubber-faced canvas, the rubber facing not only affording a smooth sur-
face but preventing the plastic material from sticking to the band.
At the sides of the table 29 are fixed parallel fences 43, 44 for regulating the
width of the sheet and preventing the plastic material from spreading laterally
beyond the edges of the endless band 37, these fences extending forward from
the rear end of the table 29 to a point in advance of the rollers 30, 31, near the
cutting mechanism. A gauge 45 for determining the thickness of the layer
of material to be fed between the rollers 30, 31, consists of a straight edged
blade extending horizontally across the table immediately in rear of these rollers
and fixed adjustably to the side frames 36 of the machine. The discharge
outlet 18 of the mixer is placed directly above that portion of the table 29 (and
band 37) which lies towards the rear of the gauge 45. In order to free the
endless band 37 from any particles of the plastic material which may adhere to
it, the band is caused to pass between transverse blades 46, 47 which scrape and
clean its upper and lower surfaces.
If a design of any sort is to be impressed upon the slabs, this is done by means
of the upper roller 31 which for the purpose would be embossed with the counter-
part of the required design. Usually, and particularly in the case of plain flat
slabs, the upper surface of the slabs is covered with paper, which is fed from a
continuous roll 48 mounted on overhead bearings 49 and led as indicated in
Figure 1 over the upper roller 31 by which the paper is drawn from the roll
and impressed upon the surface of the material in its passage between the
rollers 30, 31. The other face of the slabs may also be covered with paper if
desired, the paper for the purpose being fed from a roll (not shown) mounted
below the level of the table 29 and led over the end roller 38.
The continuous sheet emerging from between the compressing rollers 30, 31,
is conveyed by the longitudinal movement of the endless band 37 to the measur-
ing and cutting apparatus whereby the sheet is divided into the required lengths.
This apparatus consists of a guillotine knife 50 housed within, so as to rotate
with, a roller 51 journalled in or upon bearings in the side frames 36 of the
machine, the height of the roller being adjusted, by means of screws 53 sup-
porting the bearings in vertical guides 52, so as just to clear the slab as the latter
passes beneath the roller. Upon one of the end trunnions of this roller is fixed
a spur wheel 54 driven (preferably from the roller 30 as shewn) through a change
wheel 55 so that roller 51 makes one complete revolution exactly in the time
occupied by the required length of sheet in passing a given point. The knife 50
is normally held retracted within the circumference of the roller 51, but upon
coming vertically over the sheet as the latter passes beneath the roller, the knife
(whose edge is preferably serrated) is caused to strike suddenly downwards a
distance sufficient to cut or indent the upper surface of the sheet from side to
side to such a depth as to form a line of weakness whereat, on reaching the end
of the table 29, the lengths thus demarcated become readily detached from one
another.
The detail views Figures 4 and 5 illustrate one mode and Figures 6 and 7

page_text: another mode of effecting the descent of the knife at the required moment. In
both cases the knife 50 is normally held, by means of springs 56, retracted so
that its edge 57 which is parallel to the axis of the roller 51 is within the cir-
cumference of the latter, the knife blade working in and out in diametrical
guides 58 at each end of the roller. In the arrangement illustrated in Figures 4
and 5, the hollow trunnions 59 of the roller rotate upon stationary gudgeons 60
on the side frames 36 of the machine, the spur wheel 54 by which the roller is
driven as before described being keyed upon one of the trunnions. The
gudgeons 60 are likewise hollow, each being formed with an internal cam
surface, and with these surfaces engage the laterally projecting arms 61 on the
ends of the knife blade 50. The cam surfaces are throughout the greater part
of their circumference circular as at 62 (Figure 4) but at the point engaged by
the arms 61 when the knife is vertically over the table 29, the cams project
inwardly as shewn at 63 in Figure 4, so that the knife on being brought to this
angular position by the revolution of the roller is forced out beyond the periphery
of the latter sufficiently to indent the sheet of material as required, whilst the
continued rotation of the roller permits the springs 56 to again retract the knife
when the arms 61 have cleared the projections 63. In the arrangement shewn in
Figures 6 and 7, a pair of levers arms 64 keyed on a shaft 65 journalled in
bearings 66 in the ends of the roller 51, engage in holes in the blade of the knife
near its ends; one extremity of shaft 65 projecting beyond the end of the roller
and having keyed on it a shorter lever arm 67 which strikes against a spring
stop 68 fixed to the frame 36 of the machine in such position as to cause the
knife to descend suddenly at the moment when it comes vertically over the table.
The lever arm 67 is caused by the continued rotation of the roller to brush past
the stop 68 and upon being thus set free allows the knife 50 to be again retracted
by the springs 56.
"
The slabs as they travel beyond the band 37 are "keyed on the under side
by the action of a roller 69 mounted beneath a transverse slot in the table_29.
The surface of this roller is studded with sharp steel teeth which project slightly
above the surface of the table so that when the roller is rotated in the direction
opposite to that of the movement of the slabs, the latter in passing over the top
of the roller are scored and roughened on their underside by the teeth. The
roller 69 is driven by a spur wheel 70 on one of its gudgeons gearing with a
similar wheel 71 on the gudgeon of the roller 39 which is caused to rotate by
the friction of the endless travelling band 37. A wire brush roller 72
mounted beneath and in contact with the keying roller 69, and driven therefrom
but at a higher velocity, serves to keep the teeth of the keying roller clean.
In place of the keying roller might be used a comb consisting of a serrated
blade mounted transversely of the table and having teeth projecting above the
level of the latter, the blade receiving a slight to and fro lateral movement from
suitable gearing.
The slabs on passing beyond the end of the table 29 may be delivered on to
trays or on to an endless band or bands running on an even surface for con-
veyance to a convenient place where they may be dried.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. A machine for the continuous production from plastic material of slabs of
plaster, cement or composition in the form of a continuous sheet adapted to be
subsequently separated into predetermined lengths, consisting essentially of a
single pair of pressing rollers mounted the one above the other; an endless
travelling band passing between the rollers and adapted to receive the plastic
material fed to it and to convey said material between the rollers; a table whose
surface is level with the top of the lower roller and upon which the endless band

page_text: is stretched and supported; means for determining the width of the sheet of
material produced; and means for producing transverse lines of weakness in the
sheet, substantially as specified.
2. In apparatus of the character described for the continuous production of
slabs of plaster, cement or composition from plastic material, the employment
of means for varying at will the relative proportions of the ingredients of said
material whilst the apparatus is at work, said means consisting of separate
hoppers to contain the several ingredients in the dry state; separate conveyers
for the several ingredients each conveyer being adapted to continuously receive
the ingredient, from the hopper containing it and deliver the same to a mixer;
and devices whereby the relative speed of the several conveyers may be varied
at will whilst the apparatus is at work, consisting of a pair of oppositely coned
belt drums interposed in the driving gear of each conveyer, a fork for deter-
mining the position of the driving belt upon said drums, and a nut upon which
said fork is mounted working on a leading screw adapted to be rotated by hand,
substantially as specified.
3. In apparatus for the continuous production of slabs of plaster, cement or
composition from plastic material, the combination with a table, a pair of press-
ing rollers mounted the one above and the other beneath the table for rolling the
plastic material into a continuous sheet, and an endless travelling band stretched
over the table and passing between the pressing rollers so as to convey the plastic
material through between said rollers, of mechanism for producing transverse
lines of weakness in the continuous sheet of material whereby said sheet may be
readily separated into the required lengths, said mechanism consisting of a roller
mounted transversely above the travelling band and slab thereon; change wheel
mechanism whereby the roller is caused to make one revolution concurrently
with the passage beneath its axis of a predetermined length of the sheet; a
guillotine knife housed within and parallel to the axis of the roller and normally
held retracted within the periphery of the roller; hollow trunnions for the
roller, rotating on stationary gudgeons provided with cam surfaces as described;
and lateral arms on the knife engaging with said cam surfaces so as to cause the
knife edge to be suddenly forced out beyond the periphery of the roller when
brought directly over the sheet, substantially as specified.
4. In apparatus for the continuous production of slabs of plaster, cement or
composition from plastic material, the combination with a table, a pair of press-
ing rollers mounted the one above and the other beneath the table for rolling
the plastic material into a continuous sheet, and an endless travelling band
stretched over the table and passing between the pressing rollers so as to convey
the plastic material through between said rollers, of mechanism for producing
transverse lines of weakness in the continuous sheet of material whereby said
sheet may be readily separated into the required lengths, said mechanism con-
sisting of a roller mounted transversely above the travelling band and slab
thereon; change wheel mechanism whereby the roller is caused to make one
revolution concurrently with the passage beneath its axis of a 'predetermined
length of the sheet; a guillotine knife housed within and parallel to the axis
of the roller and normally held retracted within the periphery of the roller;
lever mechanism mounted on the roller and connected with the knife and adapted,
when the latter is brought directly over the sheet of material to be so operated
by contact with a spring stop on the frame of the machine as to cause the knife
edge to be suddenly forced out beyond the periphery of the roller, substantially
as specified.
"
5. In apparatus for the continuous production of slabs of plaster, cement or
composition from plastic material, wherein the slabs as produced are caused to
travel in succession along a table, the employment of apparatus for "keyingi
or roughening the underside of the slabs, consisting of a roller mounted beneath
and transversely of the table and having teeth projecting above the surface of

page_text: the table, said roller being caused to rotate in a direction contrary to that in
which the slabs themselves travel and being provided with automatic cleaning
apparatus for the teeth consisting of a cylindrical brush which is caused to rotate
in contact with and at a higher velocity than the roller, substantially as specified.
Dated this 20th day of December 1899.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.