IMPROVEMENTS IN THE CUTTERS OF WOOD PLANING MACHINES AND AN APPLIANCE FOR GRINDING THE SAME
Year: 1884

page_text: I JOHN RAWLINGS of 78 Hackney Road London in the County of Middlesex
American Organ case Manufacturer do hereby declare the nature of my inven-
tion for IMPROVEMENTS IN THE CUTTERS OF WOOD PLANING MACHINES AND AN
APPLIANCE FOR GRINDING THE SAME to be as follows
-
A spiral or twisted cutter in the form of an Archimedian screw for planing flat
boards of hard and curly woods
The blades or knives are made of steel or iron faced with steel and are hammered
or rolled to the required twist and bolted to a square shaft which is also twisted to
the form of the blades.
The blades cut the wood at a horizontal angle of 22 degrees more less according
to the nature of the wood to be planed
The blades owing to their twisted form cut only a small portion of wood at one
time but cut that continuously
The blades draw gently into the work and shear small portions from side to side
of the wood and thus avoiding the shock of a simultaneous chop
The blades being continuously cutting keep the wood firmly on the bed of the
machine there being no opportunity to rise between the blades as three or more
are cutting at the same time
The object of this form of cutter is to do the work efficiently with slow speed
and a small amount of power
The automatic grinding machine is made to grind the ever varying twist of the
blades at a true and equal distance from the centre of motion
To acquire this I have a swing carriage on which is placed a spindle carrying an
emery wheel balanced by means of two adjusting weights which work automically
on a lever bar placed above the swing carriage and which slide forward when the
machine is grinding and backward when the emery wheel is not grinding
A screw working on a pivot is attached to the lever standard with a nut and
lock nut to set the swing carriage at the required distance from the centre of
motion and insure the emery wheel not descending below that distance
To keep the blade which is to be ground in the desired position I have in
adjustable stop against which the face of the blade slides in its course where the
emery wheel is grinding it

page_text: A pulley and weight is attached to the cutter spindle to keep the face of the
blade fumly against the stop while being passed from end to end under the emery
wheel
On the bed of the machine is placed a plate that is mide to turn on its centro so
as to adjust the angle of the twisted blade to the angle of the emery wheel and
attached to the pin of the plate is an adjustible screw for sliding the plate from
back to front so as to give the required angle of clearance to the cutter
On the plate is fixed a sliding carriage to carry the spindle and blades right and
left under the emery wheel and which is worked by means of a scrow or gear
driven directly or indirectly from the countershaft by an elastic band for its
varying position.
1 JOHN RAWLINGS of 78 Hackney Road in the County of Middlesex London F
American Organ cast Manufacture do hereby declare the nature of said inven
tion for IMPROVEMENTS IN THE CUTTERS OF WOOD PLANING MACHINES AND AN
APPLIANCE FOR GRINDING THE SAME and in what manner the same is to bo
performed to be particularly described and ascertained in and by the following
statement
-
Heietofore there has been a difficulty in producing a revolving cutter which
should be perfectly suitable for hard or knotty or curly woods which have there-
fore often to be planed by hand Now by my invention I overcome this defect
and produce a cutter which while very suitable for soft or middling hard woods
18 also very suitable for hard knotty or curly woods and produces perfectly true
work For this purpose I construct a helical or twisted cutter in the form of an
archimedian scow and an automatic machine for grinding the cutter blades
Figure 1 of the accompanying diawings is a side view of my twisted cutter
and Figuic 2 18 an end view of same but drawn to a four times laiger scale
The blades S in this case shown four in number, (but they may be only two or
three or they may be more than four in number) are made of steel or iron faced
with Steel and are hammered rolled or otherwise formed to the requned I wist and
bolted or otherwise secured to a square shaft l' as here shown or to a shaft having
as many sides as there are blades The shatt is also twisted to correspond to the
form of the blades S
It will be observed that with ordinary straight blades for revolving cutters each
blade in its turn chops off a kind of shaving the whole width of the board and

page_text: then after an interval the next blade, and so on, thus causing a continuous trembling
of the board and consequent unevenness in the work done and shocks to the
machine Nor do such blades by any means cut each time of touching the board
But in my construction of cutter the blades cut at an angle of 22+ degrees with
the horizon more or less according to the nature of the wood to be planed, and the
blades owing to their twisted form cut only a small portion of the wood at one
time but cut that continuously The blades thus draw gently into the work and
shear small portions from side to side of the wood thus avoiding the shock of a
Simultaneous chop
The blades being continuously cutting will also keep the wood firmly and
without vibration on the bed of the machine there being no opportunity to use
between the cutters as two or more are cutting at the same time
This cutter will do the work efficiently with slow speed and small power
A collateral advantage is that the shavings are thrown out in a slanting direction
side ways and not into the working parts of the machine as with the ordinary
cutters
The automatic grinding machine is made to grind the ever varying twist of the
blades at a true and equal distance from the centre of motion.
Figure 3 is an end view and Figure 4 a front view of a machine constructed
according to this part of my invention and with the above described cutter
inserted and the machine in the position ready for grinding one of the helical
cutter blades
A 18 & swing carriage of usual form on which is placed a spindle B carrying an
ordinary emery wheel C, but balanced by two adjusting weights D and E which
are provided with friction rollers or wheels D' and E¹ and work automatically on
a lever bar F which by a link A' is jointed to the swing carriage A and is placed
above the swing carriage and pivotted on a standard I These wheeled weights D
and E slide forward on the bar F when the machine is grinding, and backward
when the emery wheel is not at work.
The weights D and E are by set screws G' and G2 fixed to a plate G The
screw G² passes through a slot in the plate G and the weight E may thus be
adjusted in its position on the lever F and as to the distance from the fulcrum
of the latter F and F are stops on the lever F for limiting the movement of the
weight D and thereby also that of the weight E
A screw H working at one end on a pivot is attached to the lever standard I with
a nut and lock nut to set the swing carriage A at the required distance from the
centre of motion and ensure that the emery wheel C shall not descend below that
distance
The cutter spindle, with its bearings and blades undisturbed, is lifted
out of the planing machine and placed into the grinding machine as shown in
gures 3 and 4
To keep the cutter blade S which is to be ground in the desired position I have
an adjustable stop K against which the face of the blade slides in its course where
the emery wheel C is grinding it.
Instead of the counterbalance weights D and E I may as is now usual employ
a weight W which is adjustably fixed on a lower prolongation of the swing
carriage A as shown in dotted lines in Figure 3
A pulley L which may be the ordinary driving pulley fixed on the cutter
spindle and weight M is attached to the cutter spindle to keep the face of
the Blade S firmly against the stop K while being passed from end to end unde
the emely wheel C The latter is driven at a quick speed by endless strap or
gut from a pulley on the countershaft A2 on which the swing carriage 18 loosely
mounted.
On the bed V of the machine is placed a slide rest having the usual three motions
viz pivotting round vertical centre traversing motion and back and forward
motion The plate N is made to turn on its vertical centre : so as to adjust
the angle or direction of the twisted blade S which is being ground to the angle
or direction axis of the emery wheel, and attached to the pin of the plate is an

page_text: adjustable scrow P for sliding the plate N forward or back so as to give the
required cutting bevel or angle of " clearance" to the cutter blades.
On the plate N 18 attached a sliding or traversing carriage Q which can slide
on a V shaped bed and is adapted to carry the spindle T and blade S right and
left under the Emery wheel O and which is worked by means of a screw R or
gear which may be driven directly or indirectly from the revolving counter
shaft A of the swing carriago by an elastic band for its varying position or as
it is preferred and as here shown the scrow R is turned by handwheel R¹
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 I am
aware that it has heretofore been proposed to use helical cutting blades in wood
working machines, such blades being fixed by means of a clip plate and set screws
and provided with other set screws for setting the blade more or less forward but
what I claun is
First A cutter spindle formed with two or more helical faces on each of which
a correspondingly formed cutting blade is bedded and which is fastened thereto
in such manner that the blades need not be removed till they want renewing
Bubstantially as set forth
Second -A cutter blade grinding machine having a swing frame wherein an
emery wheel is mounted, which swing frame is adjustably counter-balanced, a
stop being provided for keeping the emery wheel in proper position relatively
to the cutting blade to be ground, the cutter spindle being mounted in a 'slide
having a stop which comes against the face of the blade, and the cutter
spindle being provided with counterweight for holding the blade up against the
aforesaid stop substantially as set forth
rest
'
Third The construction of cutter, and of cutter blade grinding machine, as
shown on the drawing