Improvements in Chucks for Lathes.
Year: 1893

page_text: Date of Application, 11th Nov., 1893
Complete Specification Left, 1st Aug., 1894-Accepted, 1st Sept., 1894
Improvements in Chucks for Lathes.
We, THOMAS DODD and GEORGE OULTON, both of 8, Stanley Street, Liverpool,
in the County of Lancaster, Brassfounders, do hereby declare the nature of this
invention to be as follows:-
This invention has for its object a chuck for lathes, and is designed more
especially for chucking objects of varying sizes and shapes, and likewise for changing
the axis or centre of the work and enabling the various parts thereof to be turned,
bored or screwed without having to remove the work from or to adjust it in the
chuck, as is the case when the common ordinary chucks are employed. Our invention
is especially applicable for chucking irregular shaped objects such as taps, cocks,
etcetera, which require to be centred two or more times.
In carrying our invention into effect, the plan which we prefer at present is to
form the chuck of a strong open frame (preferably double armed) the screwed end
of which fits the mandrel of the lathe head. This frame is provided with two or
more dogs capable of rotating on radial axes at right angles to the axis of the
lathe mandrel and also of simultaneously sliding in a radial direction in the frame to
grasp or release the work. This radial sliding motion is produced by means of.
rocking arms engaging at one end the sliding dogs, and operated at the other by a
rotatable double screw which is located at right angles to the axis of the lathe
mandrel. The screw is cut with a right and left handed thread and provided with
nuts in which the levers engage. It will be understood that, when this screw is
rotated by means of a key, or in other suitable manner, the nuts are travelled in
opposite directions, operating the two levers simultaneously, which in their turn
operate the sliding dogs and cause them to approach or recede from the centre at
equal speed, thus grasping or releasing the work and forming a self centering
mechanism. These levers are preferably so centred or pivoted that a considerable
leverage is brought to bear upon the dogs. The dogs may be provided with jaws
or their equivalent if desired, for more readily holding the work, and these jaws
may be socketed into the dogs and their durability increased by working on a base
of hardened steel or other suitable material. Means are provided for firmly locking
the dogs in any given position (preferably at every revolution) thus forming not
only a self centering but a quartering chuck also.
The mode of action is as follows-
To bore an object having, for example, two axes at right angles to each other,
which must of necessity require two separate borings, the work is placed within
the chuck and grasped by the jaws in such a manner that one of its centres or axes
coincides with the axis of the lathe mandrel. After this part has been bored, the
work is rotated (say one quarter revolution) without removing it from the chuck,
and the other part of the work is centred for boring by locking the dogs in the
required position. The open frame of the chuck enables work of considerable size
and of very irregular shape to be held in the chuck.
We have described one way in which our invention may be carried into effect,
but it must be understood that, having once given the general idea, various
alterations may be made in the actual construction without departing from the
principle of the invention.
Dated this 10th day of Novemba 1002

page_text: We, THOMAS DODD and GEORGE OULTON, both of 8 Stanley Street, Liverpool
in the County of Lancaster, Brassfounders, 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 has for its object a chuck for lathes and is designed more
especially for chucking objects of varying sizes and shapes, and likewise for
changing the axis or centre of the work and enabling the various parts thereof to
be turned, bored or screwed without having to remove the work from or to adjust
it in the chuck, as is the case when the common ordinary chucks are employed.
Our invention is especially applicable for chucking irregular shaped objects, such
as taps, cocks, etcetera, which required to be centred two or more times.
The invention is best described by aid of the accompanying drawings in which,
Figure is an elevation, partly in section,
Figure 2 a section through zz Figure 1,
Figure 3 a similar view with the bridge in a closed position and not open as
in Figures 1 and 2,
Figure 4 end view of machine and,
Figure 5 section through Y Y Figure 1.
In these A is a strong open frame (preferably double armed) the screwed end
of which B fits the mandrel of the lathe head (not shown). This frame A is
provided with two or more dogs C capable of rotating on radial axes at right
angles to the axis of the lathe mandrel and also of simultaneously sliding in a
radial direction in the frame to grasp or release the work. This radial sliding
motion is produced by means of rocking arms D D engaging at one end the sliding
dogs, and operated at the other by a rotatable double screw E which is located at
right angles to the axis of the lathe mandrel. The screw E is cut with a right
and left handed thread and provided with nuts F F in which the levers D D engage.
It will be understood that, when this screw is rotated by means of a key, on squared
end d, or in other suitable manner, the nuts are travelled in opposite directions,
operating the two levers simultaneously, which in their turn operate the sliding dogs
and cause them to approach or recede from the centre at equal speed, thus grasping
or releasing the work and forming a self centering mechanism. These levers are
preferably so centred or pivoted that a considerable leverage is brought to bear
upon the dogs. The dogs may be provided with heads or jaws G or their equivalent
if desired, for more readily holding the work, and these jaws may be socketted into
the dogs and their durability increased by working on a base of hardened steel or
other suitable material. In order to lock the dogs in any given position, preferably
at every quarter turn, collars H slide on feathers on the dogs and are provided
with ratchet teeth on their sides and edges. Two pairs of ratchet spring pawls II,
JJ are provided fitting into these ratchet teeth, which face opposite ways and
thus when in position prevent movement either way. One set II of the spring
pawls are attached to yoke or bridge K and moves with it, the other J J oscillates
on a stationary pivot on frame and is forced into the locking position by the shape
of yoke K. Yoke K is formed with two eyes surrounding ratchet collars H and
sliding thereon, it has a pair of stops L, which at a given-point strike against the
frame, and as its travel is not quite 180°, it can, for each oscillation only bring one
of the four ratchet teeth at each movement to the stopping point. It thus becomes
not only a self centering, but a quartering chuck likewise.
The mode of action is as follows:-
To bore an object, having for example, two axes at right angles to each other,
which must of necessity require two separate borings, the work is placed within
the chuck and grasped by the jaws in such a manner that one of its centres or axes

page_text: coincides with the axis of the lathe mandrel. After this part has been bored, the
work is rotated (say one quarter revolution) without removing it from the chuck,
and the other part of the work is centred for boring by locking the dogs in the
required position. The open frame of the chuck enables work of considerable size
and of very irregular shape to be held in the chuck.
This action is effected as follows-
The article to be centered is firmly held between the dogs or their jaws by
bringing these latter tight up against it by turning the right and left handed screw
and bringing the yoke into the closed position shown in Figure 3 and in dotted
lines in Figure 4. When one boring is done, the yoke is brought back into the
position shown in Figure 2, then back to closed position. This turns the dogs one
quarter turn and again locks them, the spring pawl holding the ratchet from
turning in one direction and the other pawl pressed into position by the yoke in
passing holding it from moving in the opposite direction.
We have described one way in which our invention may be carried into effect,
but it must be understood that, having once given the general idea, various
alterations may be made in the actual construction without departing from the
principle of the invention.
It is obvious, for instance, that registering pins or clips could be used to enter
the dogs on the four sides and guide them and hold them exactly on the quarter,
also that the right and left handed screw could be done away with and parallel link
motion used instead, but these would be mechanical equivalents or clumsy imitations
for the purpose of effecting the same result.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is―
1. The improvement in chucks for lathes which consists in providing the dogs
with simultaneous and equal longitudinal movement (but radial to the axis of the
lathe) and with mechanism whereby they can be rotated on their axes and stopped
and held at an exact point, such as 90° from the previous position, whereby an
article such as a cock having two or more borings (in different axis) can be bored
without resetting, each axis being made successively to coincide with the axes of
the lathe.
2. The combination of the two oscillating levers, devices for actuating them
equally and synchronously the two dogs and the mechanism whereby they can be
rotated through an exact defined arc and then locked substantially as described.
3. The arrangement of self centering and self quartering chuck substantially as
herein described.
Dated this 31st day of July 1894.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.