CODE LEIE DI DOLFIVATION.
Year: 1891

page_text: Date of Application, 10th Feb., 1891-Accepted, 21st Mar., 1891
CODE LEIE DI DOLFIVATION.
An Improved Chuck.
I, HENRY BELL, Engineer, of 1, Greenfield Place, Westgate Road, in the City
and County of Newcastle-on-Tyne, 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 relates to an improved chuck which I will describe with reference
to the accompanying drawings of which
Fig. 1 shows partly in cross section and partly in end elevation the essential
features.
Fig. 2 shows a longitudinal section thereof,
Fig. 3 being again hereinafter referred to.
Like letters of reference are meant to indicate like parts throughout the following
description.
Referring to the drawings, a is the circular body of the chuck adapted to be
attached by screw or other joint at a¹ to the lathe or other machine arbor.
Within and at the inner end of the cylindrical portion of the circular body afore-
said I place firstly a disc a' which I secure by screws a' as shown. The centre of
this disc has a hole for allowing the work or tool to pass through it and at
convenient centres in the disc the bearings for the gudgeons a' at one end of the
pawl-like jaws a³ are formed. Similar bearings are likewise formed in the cover
disc a for the corresponding gudgeons on the opposite ends of the jaws aforesaid.
This cover disc being likewise provided with a central hole similar to that above
described is secured to the body by screws at a'. It will thus be seen that the
discs a² a act as bearings for the gudgeons of the jaws a³. Within the cylin-
drical body of the chuck I further place the close fitting ring or short cylinder b
which thus works between the discs a² and a aforesaid. Traversing the outer
circumference of the ring I form a sunken rack b¹ with the teeth of which the worm
screw is designed to gear. To fit the worm screw aforesaid a portion of the
outer body of the chuck is cut away thus admitting the inner end of the worm
spindle to be mounted in the metal of the body of the chuck while the opposite end
is shown bearing in two nuts 68 64 screwed into the body of the chuck which must
be tapped to effect this purpose. The worm can thus be revolved in its bearings
by fitting the end c' of the key (see Fig. 3) into the notch in the head of the worm
spindle.
The outer semi-circular ends as of the jaws a work in corresponding longitudinal
grooves formed on the inner circumference of the ring b so that when the worm screw b³
is turned as above described the ring is likewise caused to revolve which acting on
the outer ends as of the jaws a mounted at a as shown causes the inner ends
thereof to either converge towards one another or the reverse according to the
direction in which the spindle of the worm screw is caused to revolve.
The backs of the inner ends of the jaws may be roughed where they are meant
to hold the tool or work whereby a greater grip with less liability to slipping may
be effected.
The nuts 66 take up the end thrust of the worm screw.
The rack is shown going all round the ring b; this is obviously not necessary but
it is useful in case of a tooth getting broken as then a new surface can be at once
presented to the worm screw.
Referring to Fig. 3 the end c' of the three armed key having been already
referred to, the ends e c² are designed to operate respectively the screws a³, a² and
nuts The latter may have notched heads for this purpose.
C
The working of the above apparatus is effected by the turning of the worm screw
which in turn operates the ring & through rack b'. The ring acting on the ends a³.

page_text: of the jaws a³ centred as shown, causes the inner ends of the jaws to converge or
separate for the purpose of gripping or releasing the tool or work which can be
inserted in the chuck through the central opening in the cover disc a* as herein
above shown.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The improved chuck consisting of an exterior body having an interior
cylindrical chamber in which a short cylinder or ring with an exterior transverse
rack and interior longitudinal grooves is fitted the said rack being arranged to
engage with a worm screw gear so that by the revolution of the latter the ring is
caused to revolve and actuate gripping jaws working within the ring and mounted
in end plates the several parts being arranged in respect to one another and operating
substantially as and for the purpose herein set forth.
2. The combination of parts constituting the improved chuck arrangement sub-
stantially as herein set forth.
Dated this Oth day of Fahmi 1801
A. CRAWHALL CHAPMAN,
3, St. Nicholas' Buildings, Newcastle-on-Tyne,
Patent Agent for Applicant.