Improvements in Multiple Drill Apparatus for Cylindrical Boiler and other Shells:
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Multiple Drill Apparatus for Cylindrical Boiler and
other Shells:
I, JAMES YATES FOSTER, of the Firm of Joseph Foster and Sons, of Soho Foundry,
Preston, in the County of Lancaster, Engineer, do hereby declare the nature of
this invention to be as follows:-
This invention relates to improvements in drilling machines in which several
drills are operating at one time in the same circumferential or longitudinal seam of
a boiler or other cylindrical shell.
By this invention it is possible to use simultaneously a larger number of drills
than have hitherto been used whilst having them always radially directed.
The gearing necessary for operating the large number of drills which can be
accommodated on this machine is also much simpler than in the previous machines
of this class.
The description of the machine is as follows:
:--
On a circular turn-table, the shell to be drilled is clamped by several screw
clamps worked simultaneously by suitable gear. On each of three strong strong
standards fixed to the base frame, is fitted a vertically sliding bracket all three
being moved simultaneously by screws geared together. These sliding brackets
carry an annular frame in which revolves a ring supported and guided by anti-
friction bowls. This ring has on one side teeth gearing with a pinion which
slides vertically with the ring frame on a shaft which is driven by bevel gear
from a main horizontal driving shaft.
On the upper face of this ring are bevel teeth which gear with pinions on the
drill spindles.
On the top of the annular frame each free to be moved round it are a number
of carriages capable of being clamped in position.
Each of these carriages carries a radial drill spindle, each spindle being grooved
for a key in the bevel pinion which drives it. through which it can slide while
it turns with it. Each drill spindle has its own feeding mechanism advancing it in
opposition to a spring, which gives a quick return of the drill spindle when it has
completed its forward stroke, air cushions being provided to deaden the shock of
return.
A supplementary standard carrying a number of radial drills arranged vertically..
over each other, and capable of vertical adjustment, is attached to the machine
for drilling the longitudinal seams, but to this no claim is made.
In the machine above described the drilling apparatus is external to the shell
but when for shells of large diameter, the drills with their mounting and gearing,
may be arranged internally.
In this case the annular frame is carried on a telescopic vertically sliding
standard. On the annular frame are arranged the drill carriages as above
described, but with the drills pointing radially outwards. An annular table can

page_text: revolve round the central standard and on this table the shell is clamped as
before. The drills for the longitudinal seams are mounted outside the shell as
before.
ABEL & IMRAY,
Agents for the Applicant.
Improvements in Multiple Drill Apparatus for Cylindrical Boiler and
other Shells.
I, JAMES YATES FOSTER, of the Firm of Joseph Foster and Sons, of Soho Foundry,
Preston, in the County of Lancaster, Engineer, 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 relates to improvements in drilling machines in which several
drills are operated at one time in the same circumferential or longitudinal seam
of a boiler or other cylindrical shell.
By this invention it is possible to use simultaneously a larger number of drills
than have hitherto been used whilst having them always radially directed.
The gearing necessary for operating the large number of drills which can be
accommodated on this machine is also much simpler than in the previous machines
of this class.
I shall describe the machine referring to the accompanying drawings.
Fig. 1 is a plan, Figs. 2 and 3 are vertical sections partly in elevation on the
lines 2-2, and 3-3 respectively of Fig. 1, and Fig. 4 is a sectional elevation of
one of the circumferential drill heads, drawn to an enlarged scale.
The above figures shew the arrangement of the drills external to the shell
to be drilled. Fig. 5 is a vertical section and Fig. 6 is a plan of the arrangement
of the drills internally when large shells have to be drilled.
Like reference letters are employed as far as possible to denote like parts in all
the figures.
Referring first to Figs. 1, 2, 3 and 4, on a circular turn-table a the shell to
be drilled clamped by several screw clamps c worked simultaneously by suitable
gear d connecting the screw spindles any one of which can be turned by a handle
applied to its end. On each of three strong standards f fixed to the base frame
is fitted a vertically sliding bracket all three being moved simultaneously by
upright screws i which are connected by bevil gear to a central wheel & con-
nected through reversing gear 7 to a wheel on the main. driving shaft m. with
which it can be engaged by a clutch n when it is desired to raise or lower the
brackets h.
These sliding brackets h carry an annular frame o in which revolves an annular
wheel supported and guided by antifriction bowls q. This annular wheel p
has on one side teeth gearing with a pinion which slides vertically with the
ring frame o on a shaft s driven by bevil wheels t one of which is fixed on the
main horizontal driving shaft m.
On the upper face of the annular wheel are bevel teeth which gear with
pinions on the drill spindles. On the top of the annular frame o, each free to
be moved round it, are a number of carriages capable of being clamped in
position where desired.
Each of these carriages carries a radial drill spindle w each spindle being

page_text: grooved for a key in the bevel pinion which drives it, through which it can slide
while it turns with it.
Each drill spindle has its own feeding mechanism advancing it in opposition
to a spring a which gives a quick return of-the drill spindle when it has completed
its forward stroke, air cushions being preferably provided to deaden the shock of
return, but as these form no part of this invention, they are not shewn. The
feeding mechanism of each drill consists of a worm on the drill spindle w driving
a worm wheel on a vertical spindle y a worm on which drives the shaft of a
cam z which acts on a projection 1 from a yoke 2 that is connected to an adjusting
screw spindle 3 screwed into a sliding nut 4 bearing preferably with balls against
the end of the drill spindle. This nut 4 is prevented from turning by projections
from its sides sliding along grooves in the inside of the yoke 2.
A supplementary standard 5 carrying a number of radial drills arranged.
vertically over each other, and capable of vertical adjustment, is attached to the
machine for drilling the longitudinal seams, but to this no claim is made as any
part of the present invention.
Referring now to Figs. 5 and 6, a is the annular turntable carrying the shell b
which has to be drilled and which is held by screw clamps c worked simultaneously
by wheels on these screws gearing with a toothed ring a which is made to revolve
when any of the clamp screws is turned by hand. f is a cylindrical shell fixed on the
base g and having fitted to slide within it another cylindrical shell h, which can
he raised and lowered by three screws i (of which only one is shewn in Fig. 5)
which are all connected by bevel gears j to a central wheel & connected through
reversing gear to the main driving shaft m by a clutch n when it is desired to
raise or lower the shell . This shell carries an annular frame o of trough like
section in which revolves the annular wheel supported and guided by antifriction
bowls , as already described with reference to Fig. 2, the annular wheel having
internal teeth gearing with a pinion that can slide on but must turn with the
shaft driven by bevil gear t from the shaft m. The drills and their carriages v
of which some are shown with and some without their covers 2, are the same as
those already described with reference to Figs. 1 to 4 inclusive, and therefore
need no farther description except that each carriage can he separately adjusted
laterally by gear at 7 consisting of a hand wheel and worm acting on a rack fixed
on the underside of the carriage v. When it is desired to turn the annular turn-
table a, the workman standing on a floor 8 carried by the shell h turns a hand-
wheel 9 and thus through bevel gears 10 and 11 turns a worm 12 which gears
with a worm ring 13 fixed to the annular turntable a.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. Multiple drill apparatus comprising a turntable on which is clamped a
vertical cylindrical boiler or like shell to be drilled-three standards with brackets
adapted to slide vertically, these brackets carrying a ring frame, within which is
guided and supported on bowls an annular wheel having teeth gearing with a
pinion adapted to slide on a vertical shaft, and other teeth gearing with bevel
pinions on a number of radial drill spindles journalled in frames fixed on the ring
frame, substantially as described.
2. The modified apparatus having the drills arranged internally comprising an
annular turntable, a cylindrical shell fixed on the base, and an internal shell
adapted to slide vertically and carrying the ring frame annular wheel and drills,
substantially as described with reference to Figs. 5 and 6.
3. In multiple drill apparatus the combination of the frames or shell f, the
brackets or sliding shell h, the vertical screws i, the bevel gearing and wheel k,
reversing gear main shaft m and clutch », substantially as and for the purpose
set forth.

page_text: 4. In multiple drill apparatus the combination of the shaft m and bevel gear.
the vertical shafts and its pinion with the annular wheel 2, and its guide bowls q
substantially as described.
5. In multiple drill apparatus the combination of the drill spindle w the worm
gear and spindle y, the cam z, projection 1 on yoke 2 screw spindle 3 and nut 4
for, feeding the drill substantially as described.