IMPROVEMENTS IN GRINDING LATHES
Year: 1885

page_text: I, HENRY GREENWOOD of Albion Works, Leeds in the County of York, Engineer
do hereby declare the nature of my invention for IMPROVEMENTS IN GRINDING
LATHES, to be as follows:-
The chief object of this invention is to provide for "backing off," or producing
by grinding the clearance on twist drills after being hardened. It also applies to
straight and taper grinding both internal and external.
The machine in which I propose to effect these operations is constructed similar
to a lathe having an ordinary slide lathe bed with fast and loose headstocks. The
fast head is fitted with a hollow spindle having a four speed driving cone, which is
intended to be used only for ordinary cylinder grinding operations. The spindle
nose is fitted with a pulley and driving pin for dead centre grinding, and also with
various chucks for different classes of work.
The loose headstock is made to adjust sideways for taper work.
The
In the centre of the lathe bed is mounted a screw, for giving motion to the
saddle and a double train of spur gearing suitable for various pitchies of twist drills,
is provided to connect the tail end of the lathe spindle with this screw.
opposite end of the screw is fitted with two separate driving motions, viz:-one
for giving a quick backwards and forwards motion to the main saddle by means of
three pulleys with open and cross belts with belt shippers, and the other for giving
a slow feed motion to the saddle by means of a worm and worm wheel. The quick
motion is required for ordinary cylinder grinding operations and the slow motion
is used when the machine is employed for "backing off" twist drills.
The main saddle is fitted upon the bed in the usual way and is provided with a
swivelling rest, which may be set at any angle and firmly locked in position.
Passing up through the hollow centre upon which this swivelling rest is pivotted
is a vertical shaft which carries at its upper end a crank plate with an adjustable
crank pin, and upon its lower end is keyed, a bevil wheel which receives motion
from a longitudinal grooved shaft mounted in front of the lathe bed. This longi-
tudinal shaft is driven from a short countershaft mounted at the back of the lathe,
by means of bevil gear and cross shaft passing through the bed. The short
countershaft at the back is fitted with a three speed cone driven from overhead,
and also a bevil wheel for driving a worm shaft which gives the slow feed motion
to the main screw from which the lathe spindle receives its motion, through the

page_text: change gear before mentioned when the "backing off" operation is required to be
performed. This worm shaft is made to drop out of gear with the screw shaft
when required. The swivelling rest which is carried by the main saddle is fitted
with a slide covering its whole length, and projecting from the underside of this
slide is a pin for receiving the eye of a crank rod fitted to the adjustable pin of the
crank plate before mentioned. The rotation therefore of this crank plate imparts
a short traverse motion to the slide. Upon the top of this slide is fitted a cross
slide which carries the grinding wheel headstocks. As therefore the slide is
traversed the emery wheel carriage will receive a reciprocating motion which
motion may be either parallel to the axis of the lathe or at any angle thereto up
to a right angle.
To grind a twist drill so as to produce the required clearance behind the cutting
edge, the drill is chucked in the usual manner and the spindle which carries the
chuck and turns in the fixed headstock is by means of the change gearing with
which it is fitted so connected to the main screw as to suit the pitch of the drill.
This screw which imparts to the saddle its traverse motion must be driven by the
worm and worm wheel or slow motion arrangement. The swivelling rest carrying
the grinding wheel must be set at a slight angle with the axis of the lathe to give
the necessary clearance to the drill.
It will now be seen that when the machine is set in motion the lathe spindle
will have a slow rotating motion and the saddle carrying the emery wheel will
have a slow longitudinal feed motion towards the fast headstock. The emery
wheel which receives rapid rotary motion from overhead gear will at the same
time have a quick reciprocating motion from the crank plate before mentioned.
This will go on until the saddle comes in contact with an adjustable stop notion
collar carried by a horizontal sliding rod. This rod is pivotted to a vertical rock
lever the lower end of which bears against a slotted sliding plate that underlies a
strut pendent from the worm shaft which transmits motion to the screw shaft.
This plate is caused by a spring to bear against the lower end of the vertical lever
and at the same to provide a support for the strut which keeps the worm shaft in
gear with the screw shaft. When however the saddle strikes the stop on the
sliding rod the rock lever will be caused to thrust back the sliding plate which
presenting its slot to the strut will cause the worm shaft to drop out of gear, and
thereby stop the feed motion.
From the foregoing it will be understood that by using the reciprocating motion
of the rotating emery wheel in combination with a saddle having a backward and
forward motion, or a slow feed motion, cylindrical objects which are rotating in
the line of centres of the lathe may be ground with great accuracy and at a
comparatively rapid rate.
2 T
100-

page_text: I HENRY GREENWOOD of Albion Works, Leeds 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:
The chief object of this invention is to provide for "backing off" or producing,
by grinding, the clearance on twist drills after being hardened. It also applies to
straight and taper grinding, both internal and external.
The machine in which I propose to effect these operations is constructed similar in
its general characteristics to a lathe having an ordinary slide lathe bed with fixed
and loose headstocks. The fixed head is fitted with a hollow spindle having a
four-speed driving cone, which is intended to be used only for ordinary cylinder
grinding operations. The spindle nose is fitted to receive a pulley and driving pin
for dead centre grinding, and also with various chucks for different classes of
work.
The loose headstock is made to adjust sideways for taper work.
In the centre of the lathe bed is mounted a screw, for giving motion to the
saddle, and a double train of spur gearing, suitable for various pitches of twist
drills, is provided to connect the tail end of the lathe spindle with this screw.-The
opposite end of the screw is fitted with two separate driving motions, viz., one for
giving a quick backward and forward motion to the main saddle by means of three
pulleys with open and cross belts, with belt shippers, and the other for giving a
slow feed motion to the saddle by means of a worm and worn wheel. The quick
motion is required for ordinary cylinder grinding operations, and the slow motion
is used when the machine is employed for "backing off" twist drills.
The main saddle is fitted upon the bed in the usual way, and is provided with
a swivelling rest, which may be set at any angle, and firmly locked in position.-
Passing up through the hollow centre upon which this swivelling rest is pivotted,
is a vertical shaft, which carries, at its upper end, a crank plate, with an adjustable
crank pin, and rotary motion is given thereto for the purpose of imparting a
traverse motion to a slide carried by and covering the whole length of the
swivelling rest.
Upon the top of this slide is fitted a cross slide which carries the grinding wheel
headstock. As, therefore, the main saddle is traversed, the emery wheel carriage
will receive a reciprocating motion, which motion may be either parallel to the
axis of the lathe, or at any angle thereto up to a right angle.
To grind a twist drill so as to produce the required clearance behind the cutting
edge, the drill is chucked in the usual inanner, and the spindle which carries the
chuck and turns in the fixed headstock, is, by means of the change gearing with
which it is fitted, so connected to the main traversing screw, as to suit the pitch of
the drill.
T
In the accompanying drawings:
Fig. 1 shews my improved grinding lathe in front elevation.
Fig. 2 is a right hand end elevation of the machine.
Fig. 3 is a plan view; and
.
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page_text: A A are standards of cast iron, and A¹ is the bed fitted to the standards in the
usual manner. B is the main driving shaft, having its bearings in the upper ends
of the standards A, and fitted with fast and loose band pulleys b for receiving a
driving belt from the main shafting, which belt is shifted from the fast to the loose
pulley, and vice versa, by a belt shifter B¹.
Mounted on the lathe bed A' is a saddle C, which receives a to and fro motion
over the lathe bed by means of a traversing screw D, which has its bearings in the
ends of the lathe bed, and is prolonged at both ends for the purpose to be presently
explained.
E is the mandril headstock in which is mounted the mandril E¹, which is
prolonged rearwards to receive a spur wheel forming part of an arrangement of
change gear e which connects the mandril with the traversing screw D in the
usual manner.
Keyed to the mandril E¹ is also a four-speed cone pulley e¹ for receiving a
driving band from a four-speed cone pulley 61 on the main driving shaft.
F is the moveable headstock, which admits of being shifted sideways of the lathe
bed for conical work.
The saddle C is cast with a socket to receive a vertical hollow stem which carries
the slide rest G.-This slide rest, it will be understood, is capable of being shifted
to any desired angle with respect to the line of traverse of the saddle, and it is
cored out for the purpose to be presently explained.
Mounted upon the slide rest G is a slide G', of a length equal to that of the slide
rest G, and fitted to this slide G¹ is a slide G2, which is capable of adjustment to
and from the work.
This slide G carries a small headstock G³, in which is mounted the spindle g of
the emery wheel g¹.
In order to equalize the wear of the emery wheel, when carried forward by the
saddle, and ensure the production of an even surface on the work, a slight endway
motion is given to the spindle g. This is effected through the slide G¹, which
receives a short endway traverse or jigging motion in the manner to be presently
described.
I have stated that the stem of the slide rest is made hollow.-This is to enable
it to receive a short vertical shaft g2, which carries a mitre pinion at its lower end
in gear with a similar pinion h on a horizontal grooved shaft H, having its bearings
in brackets bolted to the front of the lathe bed.
The short shaft g2 carries at its upper end a crank plate g³, the pin of which
engages with a rod g* connected to the underside of the slide G. When, therefore,
rotary motion is imparted, through the grooved shaft H, to the shaft g2, the con-
necting rod g' will impart a jigging motion to the slide G¹, and thereby cause the
emery wheel with its spindle to move in the same direction.
The adjustment of the slide G2 with respect to the work, is effected by means of
a traversing screw g³ mounted in the slide G¹, and passing through a nut projecting
from the underside of the slide G2. The head of the screw is squared to receive a
handle for working it.
Keyed to the spindle g of the emery wheel g¹' is a shrouded band pulley go,
which, by means of a band from the band cylinder 62 of the driving shaft B,
receives rotary motion during the traverse of the emery wheel from end to end
of the machine.
The traversing screw D is fitted, at the right hand end of the machine, with a
fast band pulley d, and two loose pulleys d'.
These pulleys receive an open and a cross belt from a long driving shaft B, the
object being to drive the traversing screw when required at a quick speed in either
direction, and thereby to run forward or back the saddle Ĉ at a comparatively
rapid rate.
To enable the screw D to traverse the saddle at a slow rate, there is keyed to
its spindle a worm wheel d², into which gears a worm i keyed to a short shaft i¹
having its bearings in a rocking frame I.

page_text: This frame is hung upon a short shaft H³, and is supported by bracket bearings
at the back of the lathe bed.
The shaft His fitted with a three-speed cone pulley h¹, which is driven by a
band from a similar cone pulley b on the driving shaft B.
Rotary motion is communicated from the shaft H₁ to the worm shaft
through
mitre wheels h³ ³, and by this means a slow rotary motion is imparted to the
traversing screw D.
To provide for the automatic stopping of the rotation of the traversing screw D
by means of the worm, the rocking frame I is held up in position by a sliding
bar I, capable of moving freely in guides at the front of the lathe bed.
This bar is held by a coiled spring in contact with the free end of a short rock
lever 12 fulcrummed at the front of the lathe bed, and pivotted at its other end to
a horizontal rod I³, also sliding in guides at the front of the lathe bed, and carrying
adjustable tappets.
The tappet is set in such a position, to suit the work in hand, that the saddle,
when it has completed its traverse towards the fixed headstock, will strike that
tappet and shift the rod, together with the bar I', end wise.
This bar, which supports, as I have said, the rocking frame I, forms a bearing
for a stud or pin 5 standing out from the underside of the rocking frame, and it is
furnished with a slot so arranged that when the bar is suddenly moved endwise,
its slot will be presented to the pin i, and the support being thus suddenly removed
from beneath the pin, the frame I will drop a distance sufficient to withdraw the
worm from the worm wheel d², and thereby stop the rotation of the traversing
screw.
To reverse the direction of rotation of this screw, and thereby to return the
emery wheel to its starting position, the attendant turns a crank handle which fits
onto the squared head of a cross shaft I turning in bearings on the lathe bed, and
carrying on its inner end a bevil pinion in gear with a bevil wheel d³, keyed on
the traversing screw spindle. He then lifts the rocking frame I clear of the sliding
bar 11 by means of a handle provided for the purpose, and the bar is then restored,
by the action of its spring 6, to its normal position.-The frame I is then allowed
to rest upon the bar, its worm i being in position to drive the traversing screw as
before.
In order to provide for the automatic reversal of the direction of rotation of the
traversing screw, the tappet rod 13 is furnished with a second tappet *, and it is
caused to operate a belt shifter I', which is connected to the tappet rod by a
rocking arm 16, fulcrummed to a bracket attached to the lathe bed.
This belt shifter has two forks, which embrace respectively the open and cross
belts of the pulleys d -As the belt shifter 15 is moved endwise, it will throw,
say, the open belt out of action, and the cross belt into action, or vice versa,
thereby reversing the motion of the screw.
The motion for effecting the shifting of the belts is derived, as is usual in planing
machines, from the traverse of the saddle.
Thus, as the saddle completes its back traverse, it will strike the tappet *** on
the tappet rod, and thereby cause, through the mechanism above described, the
sliding of the belt shifter in the direction of the arrow, Fig. 1.-On the saddle
moving in the opposite direction to the end of its course, the tappet ** will be
struck, and the reverse action of the belt shifter will take place.
It should be remarked that the driving of the traversing screw by the open and
cross belts is chiefly employed in "long grinding," but to fit the machine for this
work, the rock lever I must be disconnected from the tappet rod 13.-On the
contrary, when a slow traverse is required to be used, as in the backing of twist
drills, the rocking arm 16 must be disconnected from the belt shifter I³, and the
rock lever I must be connected to the tappet rod I³ as before.
This is readily effected by shifting the coupling pin from the rocking arm 1ª to
the rock lever I³, or vice versa.

page_text: For imparting the jigging motion to the emery wheel, the mitre wheel on the
grooved shaft H receives its motion from the short shaft H' on which the rocking
frame I is loosely mounted.
The grooved shaft H and the shaft H' are both fitted with mitre wheels, which
gear respectively with mitre wheels on the ends of a cross shaft H2, having its
bearings in the lathe bed.
To provide for the traverse of the mitre pinion h on its grooved shaft, in order
that it may follow the movements of the saddle, I connect it therewith by means
of a pendent bracket, which embraces the boss of the pinion, and I maintain the
connection of the pinion with the bracket by means of a collar attached to the boss
of the pinion.
To provide for the rotation of the work on dead centres, which may be required
when grinding, say, external cylindrical work, I fit the mandril E¹ with a disc
pulley e carrying a driving pin, which coming in contact with the tail of the
carrier secured to the end of the work, will impart rotary motion thereto.
For putting this disc pulley in action, a belt is brought down from the pulley b
on the driving shaft B.
To illustrate the mode of operating with this machine upon a twist drill to effect
the backing off, reference is made to Fig. 5, which shews such a drill secured in
place between two centres, the mandril nose being provided with a driving plate,
the pin of which enters one or other of two diametrically opposed holes in the
chuck in which the drill is centered.
The swivelling rest carrying the grinding wheel, it will be seen, is set at a slight
angle with the axis of the lathe, to effect the backing off or necessary clearance.
In carrying on this operation, the mandril will receive a slow rotating motion
from the traversing screw through the change gear, and the saddle carrying the
emery wheel will have a slow longitudinal feed motion towards the fixed headstock.
The emery wheel, which receives rapid rotary motion from the driving shaft B, as
already explained, will at the same time have a quick reciprocating motion from
the crank plate g³ and rod g.-This will go on until the saddle comes in contact
with the adjustable tappet on the tappet rod 13, when the feed motion will be
stopped. The return motion is then effected by the attendant, who for this purpose
turns the shaft I' by the crank handle as before explained. He next re-adjusts
the position of the drill with respect to the driver, giving it half a turn for the
purpose of bringing the opposite twist under the action of the emery wheel, which
is again at its starting position.-The attendant then lifts the worm of the frame I
into gear with the worm wheel d³, and the backing off operation will be repeated.
From the foregoing explanations it will be understood that by using the
reciprocating motion of the rotating emery wheel in combination with a saddle
having a backward and forward motion, or a slow feed motion, cylindrical objects
'which are rotating in the line of centres of the lathe, may be ground with great
accuracy and at a comparatively rapid rate.
The mechanism above described is also applicable for taper grinding, the adjust-
ment of the back headstock and the corresponding adjustment of the slide rest,
being all that is necessary to obtain the desired result.
Fig. 6 shews in sectional plan the mode of carrying out internal taper grinding,
a hardened steel bush being submitted to the action of the emery wheel.
In this case the emery wheel is small, and fitted to a spindle which is capable of
being readily secured to the driven spindle of the small headstock G³.
The traverse motion of the emery wheel is obtained from the throw of the crank
pin carried by the plate g³, which instead of imparting a short jigging motion, as
explained above, is now adjusted to suit the required length of traverse of the
wheel. The feed of the emery wheel up to its work is effected by the screw g³.
Fig. 7 shews the plan of employing the emery wheel for face grinding.-In this
case the traversing screw D is used for bringing the emery wheel into line with its
work, and its action then ceases, the traverse of the emery wheel over the work
being effected by the screw g³.

page_text: my
Having now particularly described and ascertained the nature of said
Invention and in what manner the same is to be performed, I declare that what
I claim is
1st The arrangement of mechanism above described, whereby a rotating emery
wheel mounted on a swivelling slide rest, receives a reciprocating motion either in
combination with, or independently of the motions of the saddle, for the purposes
above set forth.
2nd Transmitting rotary motion to the mandril of grinding lathes from the
traversing screw by means of change gear, or its equivalent, as and for the purpose
above set forth.