Improvements in Chucks.
Year: 1898

page_text: Improvements in Chucks.
I, THEODORE COVENTRY, Managing Director of the Firm Smith and Coventry
Limited, of Giesley Iron Works, Salford, Manchester, in the County of Lancaster,
Engineers, and Tool Makers, do hereby declare the nature of the said invention,
to be as follows
My invention refers to chucks which can be made to grip a bar or other article
to be operated upon and release the same while the chuck is rotating, and it 18
applicable to lathe spindles used more especially for turning, sorewing or otherwise
operating upon bars of metal, the end of which when formed as required, can be
cut off and the bar released and fed forward to give length for another article, the
construction of the chuck allowing the gup by it upon the bar or article to be
readily released and then again secured while the chuck is in rotary motion, this
being effected by a sliding cylindrical part having a groove in it for a clutch
for a lever which can be moved to and fro by the operator, the improved mechanism
of the chuck giving a powerful grip to grip the bai or article and also to release it
with comparatively little effort on the part of the operator This 18 effected by
what are termed double acting or beam toggle levers, operated by the sliding
cylinder, which toggles act upon a cylinder that slides the gripping dies endways
not only to grip the bar or article but to release them, as the wedging inclines of
the gripping dies are but slight and this gives a powerful grip but requires a
greater effort to release the dies both of which operations are effected by the double
toggle levers
The invention consists in these double toggle levers in combination and
arrangement with the other mechanism forming the chuck.
The chuck is formed and cariied upon the end of the hollow lathe spindle, the
nose of which is solid with the spindle Its end interior bore is made conical to
receive by preference three coned grippers, each of which has a groove on its
exterior segmental cylindrical end, which fits an internal flange from a cylindrical
part that is arranged to slide freely on the exterior cylindrical nose or outer end of
the hollow spindle
On the exterior end of this cylinder at the back, a ring is screwed which can be
adjustably screwed more or less on to the cylinder by holes in the ring for a
suitable key, and when adjusted can be secured by a set screw or screws
Three slots by preference are made in the lengthway of this cylinder, one for each
double toggle lever to work in, and the exterior of the cylindrical nose of the
spindle has spaces cut or milled out of it for the double toggles to work in and
for bearings for the pivots on each side of the double toggle levers for the levers
to rock in
On the exterior of said cylinder acting upon the cone grippers and operated by
the toggles, there is an exterior cylinder with a groove in its exterior for the
clutch fork which is to slide it endways to and fro, and in the interior of this
clutch fork cylinder, there are inclines to act upon the ends of the toggles and
spaces are formed therein, to permit the double toggle to oscillate

page_text: When the exterior fork cylinder is slided inwards to gup the article its inclines
rock the toggle levels and force one end of each toggle down, the ends of which
come against the said adjustable 1ng and this slides the inner flanged cylinder and
consequently the coned gupping dies into the conical hole in the spindle forcing
them firmly against the bar or article to be gupped The sliding of the exterior
clutch fork cylinder in the opposite direction releases that end of the double toggles
acting to cause the grip and the inclines on the interior of the outer clutch fork
cylinder depress the other ends of the double toggle levers which come against
the ends of the slots in the inner flanged cylinder and thus slide the coned grippers
to release them from the bar
It 18 by the adjusting ring that the cone guppers can be adjusted to the size
of the article to be gapped and so as to give the intense gip required which 18
obtained by a proper adjustment of the ring to the ends of the toggle levers which
effect the gripping action
The mechanism of the chuck can be readily taken apart and put together
again
Dated this Tenth day of June 1898
I, THFODORE COVENTRY, Managing Duector of the Firm Smith and Coventry
Limited, of Gresley Iron Works, Salford, Manchester, in the County of Lancaster,
Engineers and Tool Makers, 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
My invention refers to chucks which can be made to grip a bar or other article
to be operated upon and release the same while the chuck is rotating, and it 18
applicable to lathe spindles used more especially for turning, screwing or otherwise
operating upon bars of metal, the end of which when formed as required, can be
cut off and the bar released and fed forward to give length for another article, the
construction of the chuck allowing the gap by it upon the bar or article to be
readily released and then again secured while the chuck is in rotary motion, this
being effected by a sliding cylindrical part having a groove in it for a clutch
fork level which can be moved to and fio by the operator, the improved mechanism
of the chuck giving a powerful grip to gup the bar or article and also to release it
with comparatively little effort on the part of the operator This effected by
what are termed double acting or beam toggle levers, operated by the sliding
cylinder, which toggles act upon a cylinder that slides the gripping dies endways
not only to gup the bar or article but to release them, as the wedging inclines of
the gripping dies are but slight and this gives a powerful grip but requires a
greater effort to release the dies both of which operations are effected by the double
toggle lever.
The invention consists in these double toggle levers in combination and
arrangement with the other mechanism forming the chuck
The chuck is formed and carried upon the end of the hollow lathe spindle, the
nose of which is solid with the spindle Its end interior bore is made conical to
receive by preference three coned grippers, each of which has a groove on its
exterior segmental cylindrical end, which fits an internal flange from a cylindrical
part that is arranged to slide freely on the exterior cylindrical nose or outer end of
the hollow spindle

page_text: On the exterior end of this oylinder at the back, a ring is screwed which can be
adjustably screwed more or less on to the cylinder by holes in the ring for a
suitable key, and when adjusted can be secured by a set screw or screws
Three slots by preference are made in the lengthway of this cylinder, one for each
double toggle lever to work in, and the exterior of the cylindrical nose of the
spindle has spaces cut or milled out of it for the double toggles to work in and
for bearings for the pivots on each side of the double toggle levers for the levers
to rock in.
On the exterior of said cylinder acting upon the cone grippers and operated by
the toggles, there is an exterior cylinder with a groove in its exterior for the
clutch fork which is to slide it endways to and fro, and in the interior of this
clutch fork cylinder, there are inclines to act upon the ends of the toggles and
spaces are formed therein, to permit the double toggle to oscillate
When the exterior clutch fork cylinder 18 slided inwards to grip the article, its
inclines rock the toggle levers and force one end of each toggle down, the ends of
which come against the said adjustable 1ing and this slides the inner flanged cylinder
and consequently the coned gupping dies into the conical hole in the spindle, forcing
them firmly against the bar or article to be gripped The sliding of the exterioi
clutch fork cylinder in the opposite direction releases that end of the double toggles
acting to cause the grip and the inclines on the interior of the outer clutch fork
cylinder depress the other ends of the double toggle levers which come against
the ends of the slots in the inner flanged cylinder and thus slide the coned grippers
to release them from the bar.
It is by the adjusting ring that the cone grippers can be adjusted to the sise
of the article to be gripped and so as to give the intense grip required which is
obtained by a proper adjustment of the ring to the ends of the toggle levers which
ffect the gripping action
The mechanism of the chuck can be readily taken apart and put together
again
Fig 1, is an elevation looking at the front or cone gripper die end of the chuck
Fig 2, is a longitudinal elevation in a plane at a right angle to that of Fig. 1,
parts being shown in section in the axial line of the chuck.
a, 18 a part of the lathe bed; b, is that part of the headstock of the lathe having
the bearing for the front end of the spindle, this bearing being shown in section.
o, is a part of the hollow or tubular or partly tubular and open bar lathe spindle
shown in section
The interior of the spindle c, at the front end is bored or formed conical, the
larger end outwards to fit the cone gupping dies e, which may be made by
preference in three separate segments with sufficient spaces between them to allow
them to work to grip and release the bar or part to be operated upon.
The gripping dies c¹, are changeable and the interior bore of the dies can be made
to suit the diameter of the bar to be gripped
The exterior ends of the grippers have a groove, which fits into an inward
flange d¹, and a cylinder d, (hereinafter called the gripper cylinder) and the
interior bore of this cylinder fits so as to slide freely to and from, on the exterior
cylindrical part of the nose of the hollow spindle c
Three double toggle levers e, are used by preference to actuate the gripper
cylinder d, and there is a slot in the lengthway of the cylinder to give clear
space for each toggle lever to work in.
The inner end of the gripper cylinder is screw threaded at d³, upon which
thread a hoop or ring d, is screwed by means of holes in it and a suitable key
and when the ring d, is adjusted it 18 secured from rotation by a set screw .
For each toggle lever e, a space is milled out of the exterior nose of the spindle c,
in its lengthway to give free space for each of the toggle levers to work in, and on
each ade at the middle of these spaces a cross space 18 cut out to form a
bearing for the trunnions e¹, of each toggle lever e, to rock in there being one pivot
or trunnion on each side of each toggle lever.

page_text: '
One only of these toggle levers e, is shown in section in Fig. 2, and indicated in
dotted line in Fig. 1
In Fig 2, the toggle lever e, is shown in mid-oscillation, one end nearly touches
the ring, and the other end the end of the slot d, in the gripper cylinder d
The exterior clutch fork oylinder f, at the front end fits and slides freely upon the
exterior of the gripper cylinder d, and at its back end fits and slides freely upon
the exterior of the screwed ring d.
The interior of this clutch fork cylinder has cavities 1, to give space for the
ends of the double toggle levers e, to oscillate in, and it also has inclines f³,
In the middle
one for each end of the upper inclined surface of the toggle lever e
position in which the clutch fork cylinder f, is shown the inclines, nearly
touch but are not acting upon either ends of the toggle levers e, but if the clutch
fork cylinder f, is slided inwards, the inclines f, nearest the ring &, will oscillate
the toggle levers and their ends nearest the screwed ring d, will act upon the inner
face of that ring d', and 'force the gripper cylinder d, endways to push the
gripper, into the cone end of the spindle c, and cause them to grip the bar to
be held
A movement of the clutch fork cylinder f, in the reverse direction will make the
other inelines f, to act to cause the other ends of the toggle levers e, to come against
the ends of the alots d in the gripper cylinder d, to force it and the grippers c¹,
outwards to release their hold of the bar
By adjusting the ring d, to the ends of the toggle levers e, the intensity of the
grip may be increased or diminished
There is a die g¹, on each side of the clutch fork cylinder f¹, to fit the groove (8,
therein, and each die fits to swivel on the end of a screw g, screwing through the
end of the clutch fork g, which has its fulcrum on a shaft g³, in bearings in
projections or brackets 61, from the headstock b, of the lathe
An arm g', from the clutch fork extends below the fulcrum or shaft g³, and to it
a link g, 18 jointed, which at its other end 18 Jointed to the end of an arm gs, keyed
on a shaft g, in bearings in the lathe headstock 6, the outer end of which
shaft g', has the handle lever g, keyed upon, by which the clutch fork g, is actuated
to cause the bar being operated upon to be gripped or released.
When the lever handle g, is moved to one extreme to put on the grip, the
lever, and link 5, at the end of that movement is nearly in a straight line
which gives great pressure upon the cylinder f, when the inclines, upon it are
producing their greatest action upon the gripper cylinder d, through the toggle
levers &
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. The combination of gripping lies within the nose of a lathe spindle, a
cylinder on its exterior, alided to and fro by double toggle levers actuated by a
sliding cylinder moved by, a clutch lever and handle for both gripping and
releasing the bar or article which is being operated upon substantially as herein-
before described and illustrated by the drawings
2. The combination, arrangement and construction of chucks having double
acting toggle levers for gripping and releasing the article being operated upon
substantially as hereinbefore described and illustrated by the drawings.
D
Monah 1200
PETER J LIVSEY,
Agent