in stone planing and dressing machines
Year: 1896

page_text: Date of Application, 30th June, 1896
Complete Specification Left. 30th Mar. 1897-Accented. 15th May. 1897
I, FREDERICK WINTERHOFF of 58° Gray's Inn Road London W.C. Printers"
Engineer and Machine Maker, do hereby declare the nature of this invention to
be as follows:-
This invention has for its object and means an improvement in stone planing and
dressing machines.
The method mostly in use for preparing and levelling lithographic stones, either
rough quarried or after same have been used is by grinding same with sand and
water by hand or by means of a grinding machine, having an iron revolving disc
or stone, which revolves on top of the stone to be ground. Planing machines with
rocking knives have also been used to a certain extent, but have not found much
favor owing to their inefficientey and the snapping of the working parts caused by
the run of the table against the striker and the difficulty of keeping the stone
clamped down firm on the table of the machine when the cutting knives were
brought to bear on the stone.
The object of this invention is to prevent these objections to the use of the stone
planing machines and to overcome all these difficulties.
The said invention consists of a stone planing machine having an extending bed
nose, with rails in the shape of a V, giving greater stability and firmness to the
table of the machine over the old system and preventing the table from lifting and
running with a sudden jerk against the striker, the machine having a pair of knives.
of the shear blade pattern with 1 inch to 1 inch bottom face on the cutters, which.
are ground at an angle of 30 degrees towards the inner edge or back of blade, or
having a pair of knives of the same shape but having insertions cut into same at
regular intervals of 14 inch to 1 inch so as to be in the form or shape of a long
row of chisels, if same is to be used for rough or hard stone, so that when the
knives are placed back to back in the cutter holder, the insertions in the one knife
will correspond with the teeth or chisels in the other, these knives are then rocked
alternately from side to side on two spindles according to the run of the table, by
means of half circle geared rack and toothed segment which is fitted to a friction
clutch and which said friction clutch can be so regulated that if the strain is too
great on the rack, that same slides loosely round its shafts or inner pulley and thus
prevent the snapping and breaking of feed levers or racks, as formerly the rockers
were fixed on a spindle shaft direct and snapped if the machine was overcharged
with power or the table of the machine run too hard against the striker.
The lowering prawls are fixed onto a large ring lever having countersunk springs.
with spindles to keep them in place, which in their turn are fixed to move freely
on a projection on each side of the ratchet wheel, instead of working direct on the
shaft as formerly.
The main lever is placed towards the driving end of the machine, instead of the
front, thus giving greater freedom and working with instead of against the machine,
this also prevents the snapping of the assistant levers of the prawls and friction
clutch attached to main lever.
The machine is driven by a shaft having 3 pulleys, the centre pulley being fast
and the 2 end pulleys running loose, the belts being guided alternately on the fast
pulley by means of guide forks attached to the sliding bar shaft, the said shaft,

page_text: having a hole drilled through the square end and a corresponding hole in the
bolding up arm, so that the machine can be immediately brought to a standstill at
any part of its traverse by placing a tommy pin through the holes in the arm and
sliding bar shaft, so that both belts run on the loose pulleys only.
The connecting rod (striking gear) is fitted on the sliding bar shaft at one end
and to the bottom of a swinging lever at the other said lever being fixed on the
side standard towards the driving end, by means of a screw spindle and in its place
being connected by an arm working loosely from the reversing lever of the striker
shaft (main) whereas the old way was to fix the connecting rod direct from the
sliding har shaft to the reversing lever which very often caused said lever to break,
if the sliding bar happened to be a trifle light in its bearing.
The method formerly employed to keep the stone down on the table of the
machine, was by means of a pair of wooden rollers, fixed on each side of the
crosshead by means of 2 projections on each side of the crosshead having holes
drilled through same and the rollers then being in their turn fixed into bearer
screws fastened through said holes by means of two nuts; the stone then being
clamped up on the table by means of iron bars and stay bolts.
These rollers always required regulating according to the cutters, otherwise the
stone would rise, if same were higher or the rollers split if too low, in both cases
damaging the stones. At the same time these rollers were always in the way
owing to the shavings from the stone adhering to same and often causing the stone
to break. In this new machine the rollers are entirely done away with and to
prevent the stone from rising, I use either a dovetailed iron bar, letting the
thickest end come undermost and placing a wooden bar of the required thickness
between stone and iron bar and then screwing same up with set screws fixed
into stay bolts, this causes the wooden bar to grip the stone at the upper part
firmly and force the stone downwards thus preventing same from rising when the
cutters press on either end of the stone.
Instead of using an iron bar made dovetailed I can also use an ordinary straight
bar and use a dovetailed wooden bar, or a straight wooden bar and use a strip or
two of mill or straw board, asbestos board or a strip of sheet india rubber or
similar substance of about inch to inch depth which is either glued onto the
bottom of the wooden bar or simply placed against same in clamping the stone up.
Dated this 29th day of June 1896.
Improvements in Stone Planing Machines.
I, FREDERICK WINTERHOFF, of 58c Gray's Inn Road, in the County of London,
Printers' 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 :-
This invention for improvements in stone planing machines for preparing and
levelling the surfaces of lithographic stones, either rough quarried or after the same
have been used, has for its objects to prevent the breakage of working parts due to
the run of the table against the striker of the reversing gear and to clamp the stone
down firm on to the table of the machine.
In the accompanying two sheets of illustrative drawings:-
Fig. 1 is a left side elevation of a stone planing machine constructed according to
this invention, and Fig. 2 is an end elevation, Fig. 3 a plan and Fig 4 a cross section
on line A-B Fig. 1 of the same.

page_text: HOMICI
knife.
Fig. 7 is a cross section of a single knife with double or forward and backward
cutting edges.
Fig. 8 is a plan of a double knife requiring a forward and backward motion of the-
stone to complete a single cut.
Fig. 9 is a right side elevation of the stone planing machine and Fig. 10 a central
longitudinal section.
Fig. 11 is an end elevation of a removable knife and
Fig 12 an end elevation of the knife holder with the knife in position.
Figs. 13 and 14 are elevation and plan of the clamping arrangement for fixing the-
stone on the bed.
Figs. 15, 16 and 17 show a modification of the reversing gear.
The stone planing machine has a bed a extending beyond the feet or supports and
provided with V-guides e giving great stability and firmness to the table d of the
machine that is traversed on the bed, and preventing the table from lifting and.
running with a sudden jerk against the striker of the reversing mechanism.
The table d is traversed forwards and backwards by means of the screw e mounted
in bearings on the frame, the distance between the bearings being reduced on
account of the extended bed. The screw e is driven by means of the spur wheel el.
on its end gearing into the spur pinion e fixed on the shaft e³ on which is also fixed
the driving pulley g. On the shaft e³ are mounted the loose pulleys o, one on either -
side of the fixed pulley g. The shaft is driven alternately by a straight belt and a
crossed belt, the belts being guided by the forks g² fixed on the shaft g3 sliding in
bearings . In the mid-position-he position shown. of the forks g-both belts
will be on the loose pulleys and the machine will be stationary. The forks can be
kept in this position by means of a pin passing through a hole in the bearings g and
taking into a hole in the shaft The shaft g is prevented from turning in its.
bearings and is connected by a link g to a lever pivoted at 9' and connected by the
link having a long slot to an arm on the shaft extending across the machine
and provided with a short arm 12 that is operated at the ends of the traverses of the
table by the adjustable stops 3 first in one direction and then in the reverse back to
its original position. The effect of this slot in the link is that the shaft with its..
belt guides is moved from one extreme position to the other only after the knife has..
been reversed. The traverse of the shaft g3 moves the straight belt from off the fast
pulley g on to its loose pulley, and the cross belt is moved from off its loose pulley on
to the fast pulley or vice versa and the traverse of the table is reversed.
The knife & has a broad bottom face with the sides ground away at an angle to
form two cutting edges, a front cutting edge and a back cutting edge. The
knifeholder carrying the knife is pivoted in a crosshead sliding in vertical"
grooves in the uprights of the machine, and has teeth at one end gearing into.
a toothed sector mounted on a short shaft provided with an arm i connected by
a link to an arm on the cross shaft and reciprocated by the table as above
described, so that the knife is moved from against the stop to the stop 48 or the
reverse to bring the required cutting edge into position to cut according to the
direction of traverse.
In order to prevent any breakage of parts due to the resistance of the knife to the
motion, 'the armis fixed on the shaft by friction. The boss of the arm i where
it fits the shaft & is split and the two parts are clipped together by the scrow so
that any desired amount of friction can be produced. The hole in the boss may be
fitted with a leather or similar bush.
The crosshead carrying the knife and holder is fed by means of screws m
mounted in the cap plate of the uprights ³ and provided with worm wheels m
gearing into wormis m² on the cross shaft m³ on which is fixed a ratchet wheel m*.
Two pawls a gear with the ratchet wheel, one being straight and the other hooked.
These pawls are fixed to independent arms a pivoted on the shaft m³ on opposite
sides of the ratchet wheel and connected by separate links to the arm of the-

page_text: shaft. It will readily be seen that when the arm moves in one direction say
backwards, both pawls move towards the rear of the machine the top hooked pawl
moving forward forcing the ratchet wheel round and the bottom straight pawl slipping
back over the teeth. On the forward motion of the arın ', the bottom straight paw]
draws the ratchet wheel round, the top pawl slipping back over the teeth. The knives
are thus fed downwards for each stroke of the table.
In the modification shown in Fig. 8 of the knife, the knife o is formed with
spaces o alternating with the cutters on each cutting elge, and the spaces of the
back edge are opposite the cutters of the front edge so that during one stroke a
series of grooves are cut and the next stroke the ridges between the grooves are
removed by the other knife. In this arrangement one of the feed pawls is thrown
out of gear.
In the modification shown in Figs 11 and 12, the knife proper p slides in a
dovetail groove pl in the holder p² and is fixed by the set screws p³.
Figs. 15, 16 and 17 show a modification of the reversing mechanism, the link y³
being directly connected by the link g to the sliding belt shaft.3.
In order to clamp the stone to be planed firmly down on to the bed, wooden
strips having inclined faces are placed with the inner and inclined faces against
the stone, the projecting edge being on the bed. An iron strip 2 is placed against
the outer faces. Studs are then inserted in the nearest or most convenient holes
in the table and screws 4 in the heads of the studs are screwed firmly against the
wedge strip. This causes the wooden strip to grip the stone at the lower part
firmly and below the ends of the screws so that the stone is forced slightly
downwards and held firmly against the face of the table. The iron preserves the
wood from injury due to the fixing screws, and the wooden strip seizes hold of the
stone without any chance of crushing it. The lower projecting edge of the clamping
strip may be formed by a separate narrow strip, or the iron strip may be wedge
shaped.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declare that what I claim is :-
1. In stone dressing machines, the means for clamping the stone on to the bed of
the machine, consisting of the removable studs taking into holes in the bed, fixing
screws in the head, iron and wooden strips having projecting lower edges and situated
between the screws and the stone, substantially as described.
2. A double cutting knife for a stone planing machine consisting of a solid knife
having a flat bottom face, the two side edges of the face forming the two cutting
edges that are brought into operative position by slightly rocking the knife holder
on a pivot against one or the other of two stops, substantially as described.
3. The reversing mechanism provided with a long slot so that the reversing action
takes place at the end of the motion substantially as described with reference to the
drawings.
4. The toothed knife, substantially as described with reference to the drawings.
5. The knife having removable cutting edges substantially as described with
reference to the drawings.
6. The improvements in stone planing machines, substantially as described with
reference to the drawings.
Dated this 30th day of March 1897.
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.