Improvements in Turret Lathes and like Machines.
Year: 1898

page_text: Date of Application, 8th Nov., 1898
The
PROVISIONAL SPECIFICATION.
Improvements in Turret Lathes and like Machines.
I, STEPHEN SIMPSON, of 32, Powderham Crescent, Exeter, in the County of
Devon, Engineer, do hereby declare the nature of this invention to be as follows:
This invention relates to lathes and other machine-tools in which are employed
turrets carrying a number of tools, such turrets being rotated intermittently so
as to present the various tools successively to the work, and locked in position
during each cutting operation by a locking bolt.
In such machines as at present constructed, although provided with the usual
turret-locking bolt, the accuracy of the work produced is greatly interfered with
by the lateral movement of the turret upon its central bearing or pivot due to the
loose fit between the two which is necessary for easy turning of the turret. In
some cases hand levers and screwed bolts are provided for clamping the turret
down tightly upon its seat after each partial rotation and before bringing the
tool forward to the work, but it is found that inaccuracies are still produced, some-
times by the difference in the extent to which the clamping bolt is tightened,
and at other times by the operator neglecting the clamping altogether.
According to the present invention the turret, after each partial rotation, is
clamped down upon its seat automatically by the movement of the turret slide.
In one mode of effecting this, a rocking lever pivoted upon the turret slide is
connected at one end to a central clamping bolt extending upwards through the
turret and provided at its upper end with a head or collar resting on the turret,
while the other end of the said lever is operated by a cam-like or inclined surface
on the fixed saddle block arranged in such manner that the bolt is tightened on
the forward movement of the turret slide and released during the return move-
ment so as to allow the turret to be rotated.
In a modification, the lower end of the clamping holt may be screwed and pro-
vided with a nut having an arm adapted to come in contact with a fixed projec-
tion or cam-like surface on the saddle block, so as to clamp down and release the
turret, at the required times, by the movement of the turret slide in the saddle
block.

page_text: manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
=
This invention relates to lathes and other machine tools in which are employed
turrets carrying a number of tools or cutters, such turrets being rotated inter-
mittently so as to present the various tools successively to the work, and locked
in position during each cutting operation by a locking bolt.
In such machines as at present constructed, although provided with the usual
turret locking bolt, the accuracy of the work produced is greatly interfered with
by the lateral movement of the turret upon its central bearing or pivot due to the
loose fit between the two which is necessary for easy turning of the turret. In
some cases hand levers and screwed bolts are provided for clamping the turret
down tightly upon its seat after each partial rotation and before bringing the
tool forward to the work, but it is found that inaccuracies are still produced, some-
times by the difference in the extent to which the clamping bolt is tightened;
and at other times by the operator neglecting the clamping altogether.
According to the present invention the turret, after each partial rotation, is
clamped down upon its seat automatically by the movement of the turret slide,
and in order that the said invention may be readily understood I will now des-
cribe a method of applying it to a turret lathe of ordinary construction, reference
being had to the accompanying drawings in which:
-
Fig. 1 is a side sectional elevation of the turret and turret slide,
Fig. 2 and 3, a front view and top view; respectively, of the turret clamping
bolt and clamping lever, and Fig. 4, a part section similar to Fig. 1, shewing the
position of clamping lever when the turret is unclamped.
Fig. 5, illustrates a modification. Figs. 6, 7, & 8, a further modification.
Like letters indicate corresponding parts throughout the drawings.
Referring to Fig. 1-Upon the under side of the turret slide A is a rocking
lever B pivoted at B₁ to the said slide and connected at one end to a central clamp-
ing bolt C extending upwards through the turret D and provided at the upper end
with a head or collar E resting on the turret. The other end of the lever Bis
adapted to slide upon a strip or facing F having a plain or horizontal portion F¹
and a cam-like or inclined surface 12. The strip F is mounted upon the turret-
slide block or saddle G, and arranged in such manner that it may be adjusted
vertically as will be hereinafter described.
The bolt C is preferably keyed to the turret by a key C¹ and carries at its lower
end the usual star-wheel C2 (by which it the turret rotated in the well-known
manner) and above the said star-wheel is a groove adapted to receive the studs B2
on the lever B, the latter being forked as shewn in Figs. 2 and 3.
Thus, when the turret D is locked and the turret slide A is in its forward or
working position the lever B rests on the plain part of the strip F and the
turret is clamped tightly on its seat, as in Fig. 1; when, however, the slide A
is moved backwards to unlock the turret previous to its rotation, as shewn in
Fig. 4, the end of the lever B runs down the incline F2 so that the turret is loose
on its seat and may be rotated. On the reversal of the turret slide the end of the
lever runs up the incline again and the turret is clamped as before.
The collar E has a locking collar or nut E', and the strip F is provided with a
wedge-like support F3 having nuts F by which it may be moved longitudinally
so as to raise the strip and take up wear, or adjust the clamping pressure.
Obviously in some cases the can or incline may be upon the clamping lever
itself and adapted to come in contact with and be operated by a dog or projec-
tion upon the saddle block. Thus, in the modification shewn in Fig. 5, the cam
is formed as a separate piece B³ pivoted at B to the lever B (which latter
in this case passes through a slot in the bolt C, and has its fulcrum BT at the
front end as shewn,) and the acting part of the said cam bears against the end
of the screw A. The clamping and unclamping is effected by the piece F5 on the
saddle block G, the said piece having an inclined slot F adapted to engage with

page_text: a pin or stud B³ on the cam B³ and rotate the said cam about its pivot B* (in one
direction or the other according to the direction of motion of the slide A,) thus
bringing a higher portion of the cam against the screw A', so as to depress the
lever B and clamp the turret on its seat, or a lower portion, so as to allow the
lever to rise and release the turret. The slot F2 is so located as to effect the clamp-
ing and unclamping at the required times, and the cam B3 is retained in the
unclamped" position by the horizontal extension of the slot F engaging
the stud 15, and in the "clamped" position by its frictional pressure against the
screw A¹ having for this purpose preferably a slight flat on the part then in con-
tact with the screw. The clamping pressure is adjusted by raising or lowering
66
the screw A¹
In the modification illustrated in Figs. 6, 7, and 8, the oscillating cam-piece
is provided with projections or teeth B6, B7, adapted to come in contact with
swinging pawls or dogs F, F, pivoted at F8, F, and having stop pins F10, F1,
so as to permit each of them to swing in one direction only, on their pivots.
Thus, the turret being clamped and the turret slide moving on its backward
stroke, (in direction of arrow 1,) Fig. 6, the tooth B' on cam B³ comes in contact
with the dog F which, being prevented from swinging in this direction by its
stop pin F10, causes the cam 133 to move round on its pivot B and unclamp the
turret. The cam B³ will then be in the position shewn in Fig. 7, and as the slide A
continues its backward movement the tooth B6 on the cam comes in contact with
the dog F, swinging it away from its stop pin F1 (as shewn in Fig. 7) and allow-
ing it to fall back again to the vertical position so that, when the slide A is re-
versed and moves forward in the direction of the arrow 3 (as shewn in Fig. 8,)
the tooth B6 again comes in contact with the dog F6, which latter, being pre-
vented from swinging in this direction by its stop pin F1, causes the cam B³ to
move round on its pivot and return to its former position (as in Fig. 6,) the
lever B being thereby depressed so as to clamp the turret as before described. The
turret slide A continuing its forward movement, the dog 17 swings away from its
stop pin and allows the tooth B' of the cam to pass it, as will be understood.
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 a turret lathe or like machine, the combination, with a turret slide
having a turret mounted thereon, of a clamping lever connected to said turret by a
bolt or its equivalent and adapted to be moved or operated (by or through the
movement of the turret slide,) in a plane at right angles to the plane of rotation
of the turret so as to clamp and release the turret, substantially as hereinbefore
described.
2. In a turret lathe or like machine, the combination, with a turret slide
having a turret mounted thereon, of the means for automatically clamping and
unclamping the turret by the movement of the turret slide, substantially as des-
cribed with reference to Figs. 1, 2, 3, and 4 of the drawings.
3. In a turret lathe or like machine, the combination, with a turret slide
having a turret mounted thereon, of means for automatically clamping and un-
clamping the turret by the movement of the turret slide, substantially as des-
cribed with reference to Fig. 5 of the drawings.
4. In a turret lathe or like machine, the combination, with a turret slide
having a turret mounted thereon, of means for automatically clamping and un-
clamping the turret by the movement of the turret slide, substantially as des-
cribed with reference to Figs. 6, 7, and 8 of the drawings.
Dated this 8th day of Sentombor 1800
STEPHEN SIMPSON,
Annlicant