Machine Tools for the Purpose.
Year: 1887

page_text: Date of Application, 15th Jan., 1837
Complete Left, 15th Oct.. 1887
Complete Accepted, 2nd Dec., 1887
Machine Tools for the Purpose.
I WILLIAM CRAVEN of the firm of Craven Brothers Limited of Vauxhall Iron
Works, Osborne Street, Manchester, in the County of Lancaster, Engineers, do
hereby declare the nature of my invention to be as follows:-
My improvements relate to a compact combination and arrangement of mechanism
whereby the operations of boring chasing and turning shells are performed with
greater speed and exactness than heretofore.
By the adoption of worm and worm wheel driving gear I am enabled to place a
larger number of machines in a given floor space than heretofore and to drive the same
direct from the main shaft from above or below the floor line without the intervention
of a counter shaft or compound gearing whilst the worm wheel affords a means of
holding the hollow spindle from turning whilst the gripping jaws of the concentric
chuck employed for holding the shell are opened or closed.
In performing my invention I first mount the shell in a hollow spindle of a
head stock and so as to project through at both ends of such hollow spindle and this
enables me to bring to bear the tools carried by a pair of strong Turret or capstan
rests fitted with revolving tool holders each carrying six independent tools and
whereby the two ends of the shell are first turned down simultaneously to the exact
length and secondly the shell is bored at each extremity each operation being
performed by two tools, one roughening and the other finishing. The next operation
viz-that of chasing or screwing the hole being performed by a chasing tool and the
final operation by a template tap being passed through the hole and all such six tools
being carried as aforesaid by the same slide rest and acting simultaneously at both
ends of the shell. The larger end is then milled by a pair of rotary milling tools
carried by levers closed on the shell by a right and left hand screw.
Having thus bored and chased the shell the next operation is that of turning it on
the outside to the desired diameter and to the required shape at the point. This is
similarly effected by a spindle caused to revolve in a head stock by worm and worm
wheel gearing. The shell is driven by an internal expanding mandril with threads

page_text: fitting into the larger screwed end of shell and tightened by the mandril passing
through the spindle and having an adjusting nut on the outer end. The other end of
the shell is carried by a centre adjustable in its head stock by a spindle and hand
wheel in the ordinary manner. The bed is fitted with a slide and three carriages
traversed self-actingly thereupon by a single screw running the length of the bed-
each carriage being capable of being readily thrown in and out of gear with the screw
and each fitted with a tool holder slide to adjust the tool, two of such tools being
employed for sliding the parallel part of the shell and the other to turn the curved
part. By means of a radial bar and fixed centre the last mentioned tool holder is caused
to move on a bottom slide as the carriage is traversed on the bed and thus the tool
partakes of the requisite curve to cut the curved part of the shell simultaneously with
the other two tools sliding the parallel portion.
My improved mechanism is provided with adjustable gauges carried by a screw to
gauge the diameter and length and so to work the shells to the exact lengths, diameter
and sizes in all parts.
4
JOHN G. WILSON,
Agent for the Applicant.
COMPLETE SPECIFICATION.
20
Improvements in Boring, Chasing, and Turning Shells, and in
Machine Tools for the Purpose.
I WILLIAM CRAVEN of the firm of Craven Brothers Limited of Vauxhall Iron
Works, Osborne Street Manchester in the County of Lancaster Engineers do hereby
declaro the nature of my invention and in what manner the same is to be performed 2
to be particularly described and ascertained in and by the following statement:-
My improvements relate to a compact combination and arrangement of mechanism
whereby the operations of boring chasing and turning shells are performed with
greater speed and exactness than heretofore.
By the adoption of worm and worm wheel driving gear I am enabled to place a 3
larger number of machines in a given floor space than heretofore and to drive the
same direct from the main shaft from above or below the floor line without the
intervention of a counter shaft or compound gearing whilst the worm-wheel affords a

page_text: means of holding the hollow spindle from turning whilst the gripping jaws of the
concentric chuck employed for holding the shell are opened or closed.
On the accompanying drawing Fig. 1 is a front view of my improved arrange-
ment of mechanism for boring and chasing the shell in accordance with my invention.
Figs. 2 and 3 are right and left hand end views respectively of the same mechanism
and Fig. 4 is an end view of the milling apparatus affixed to the same head stock.
C
The shell is held (as indicated by the dotted lines) in a hollow spindle a by a con-
centric chuck at each end of the spindle each fitted with three hardened steel jaws a²
to grip the shell centrally by turning the two outer rings a³ which open or close the
gripping jaws. The spindle a runs in brass steps with collar bearings as illustrated
and is driven by a worm wheel c and a worm d on a spindle d¹ with fast and loose
driving pulleys e. This mode of driving enables a great number of machines to be
placed in a small floor space and to be driven direct from the main shaft either above
or below the floor line whilst the worin wheel affords a means of holding the spindle a
from turning round whilst the outer rings a³ are turned to actuate the gripping jaws a².
The shell thus mounted projects through at both ends of such hollow spindle a and
this enables me to bring to bear the tools carried by a pair of strong Turret or Capstan
rests and g fitted with revolving tool-holders-cach carrying six independent tools
and whereby the two ends of the shell are-first turned down simultaneously to the
exact length required and-secondly the shell is bored at each extremity, each
operation being performed by two tools, one roughening and the other finishing-the
next operation viz:-that of chasing or screwing the hole being performed by a
chasing tool and the final operation by a template tap being passed through the bole
and all such six tools being carried as aforesaid by the same slide rest and acting
simultaneously at both ends of the shell. The six tools are held in a revolving tool-
holder with accurate notches f and catch to hold them in position, also a handle/1
on the top for fixing the tool holder. The end of the shell is turned by the operator
working the slides by hand. The boring and chasing are effected self-actingly and
simultaneously at both ends of the shell by the traversing screw of each of the
slides and g being similarly geared and driven (except as to speed). It will only
therefore be necessary to describe the mechanism of one slide for instance the
left hand one: The screw h of this slide is geared by a worm-wheel to a
worm h² carried by the pinion shaft i. This shaft is fitted with a pair of clutch boxes
one at either extremity and so arranged as to be driven at the different speeds
necessary for boring and chasing-the two clutch box levers and being connected
together by a connecting bar ja to prevent accident and to ensure one being out of
gear whilst the other is in gear and vice-versa.
For boring purposes the necessary motion of the slide is obtained by putting the
clutch into gear with the spur wheel k-which spur wheel is driven by a belt from
a pulley on the main driving shaft and through the intervention of a spur
wheel and pinion l' as illustrated.
For chasing purposes the same slide is traversed by putting the opposite clutch
inio gear with the spur wheel m which receives positive motion direct from the main
driving shaft d' being geared thereto by the spur wheel m¹. The chasing tool is put
in and out of gear with the screw h by an eccentric motion operated by the handle n.
The handle n is provided for putting the slide rest in and out of gear with the
screw by means of a pair of jaws which close upon the screw by turning the
handle n in one direction and so form a nut for traversing the slide rest whilst
turned in the other direction the jaws open and the traverse ceases.
To return the slide rest back quickly to the starting point I provide a rack o and
pinion o operated by the hand lever o. The horizontal screw p is provided with a
pair of adjustable gauges q which enable the shells to be worked to exact lengths and
sizes. The inilling apparatus fixed on the left hand of head stock is fitted with
two rotary milling tools carried by levers capable of being closed on the shell
by a right and left hand screw, this operation can be done after the shell is
turned at the large end. The head stock and bed of the machine are formed in
one strong casting with a doors and shelves in the inside to contain the tools &c.

page_text: Having thus bored and chased the shell the next operation is that of turning it
on the outside to the desired diameter and to the required shape at the point.
This is similarly effected by a spindle caused to revolve in a head stock by worm
and worm-wheel gearing.
For this purpose it is mounted between a pair of head stocks forming a shell
turning lathe as illustrated by front view Fig. 5 plan view Fig. 6 and right and
left hand end views Figs. 7 and 8 respectively of the accompanying drawing.
The spindle A of this lathe runs in steps A' in the head stock A* and is
similarly driven by a worm B and worm wheel B₁ and fast and loose pulleys C.
The shell (indicated by dotted lines) is driven by an internal expanding mandril D
with screw threads fitting into the larger screwed end of shell and tightened by
the mandril D passing through the spindle A and having an adjusting nut D¹ on
the outer end. The other end of the shell is carried by a centre E adjustable in
its head stock E¹ by a spindle and hand wheel E' in the ordinary manner.
The bed F is fitted with a slide F and three carriages G G G traversed self-actingly
thereupon by a single screw H running the length of the bed each carriage being
capable of being readily thown in and out of gear with the screw H and each fitted
with a tool holder slide I to adjust the tool-two of such tools being employed for
turning the parallel part of the shell and the other to turn the curved part. By
means of a radial bar J and fixed centre J₁ the last mentioned tool-holder is caused
to move on an extra bottom slide K as the carriage is traversed on the bed-and
thus the tool partakes of the requisite curve to cut the curved part of the shell
simultaneously with the other two tools sliding the parallel portion. The traversing
scrow H is operated by an eccentric H on the head-stock spindle A imparting an
oscillating motion to a lever H2 the shorter arm of which carries a pawl H³ engaging
with the spur-wheel H keyed to such screw.
My improved mechanism is provided with adjustable gauges L carried by a
screw M to gauge the diameter and length and so to work the shell to exact lengths
diameters and sizes in all parts.
Having thus particularly described and ascertained the nature of the said invention
together with the best means with which I am acquainted for carrying the same into
practical effect I declare that what I claim is
1st. The improvements in boring, chasing and turning shells and in machine tools
for the purpose substantially as hereinbefore described.
2nd. The improved combinations and arrangements of mechanism for boring
chasing and turning shells substantially as herein before described and illustrated on
the accompanying drawing.
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