An Improved Tool for Tapering the Bolt Holes in Shaft Couplings.
Year: 1890

page_text: Date of Application, 23rd Jan., 1890-Accepted, 1st Mar., 1890
COMPLETE SPECIFICATION.
An Improved Tool for Tapering the Bolt Holes in Shaft Couplings.
⚫I CLAUDE CARTER Manager at the Works of Messieurs Hetherington and Company
of Pollard Street, Manchester in the County of Lancaster, Machine 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 and accompanying drawings :-
My said Invention refers to an improved tool for tapering the bolt holes of flanged
shaft couplings as for example in the couplings of propellor shafts. The several
lengths of such shafts are usually connected by placing the flanged ends together and
passing bolts or studs through the flanges and securing them by means of nuts. In
order to give greater security and strength to the connection the bolts or studs are
usually made tapered and the holes in the flange couplings are similarly tapered to fit
the bolts. The tool which forms the subject matter of this invention has been devised
to provide an efficient and certain method of imparting the requisite taper to
the said holes.
To render the construction of the tool perfectly clear I have attached hereunto
a sheet of drawings to which the following description will more particularly refer.
Fig. 1 is a side view of the apparatus the boring bar being drawn in section.
Fig. 2 is a similar side view of the apparatus as clamped to the flanged
coupling.
Fig. 3 is a plan view of the tool from the lower side.
Fig. 4 is an end view of Fig. 1.
Fig. 5 is a detached view of the bracket to support the gear for driving the
boring bar.
Fig. 6 is a section of the tool frame at the line A. B Fig. 2.
The moving parts of the apparatus are supported in a bracket frame a capable of
being suspended from a crane or in slings attached or hooked to the shackle b. The
boring bar c is carried in bearings a¹ a² a³ in the bracket a and is driven from the
wheel d which is rotated either by hand or by power. The axle of the wheel d carries
a pinion e gearing with a spur wheel fand the axle of the spur wheel of has at its
other end a bevel wheel g gearing with and driving the bevel wheel h which runs in
a sleeve i projecting from the bearing a³ on the bracket a and is prevented from
leaving the sleeve i by a set screw j which is screwed through the sleeve i and projects
into a groove turned in the boss of the bevel wheel h. The boring bar c has a screw
thread cut upon it from about the part marked to the back end and this screwed portion
passes loosely through a clearing hole in the boss of the bevel wheel h but is connected
by means of a feather k sliding in a groove in the screwed portion of the boring bar c
so that the bar c can slide to and fro in the boss of the wheel while it is at the same
time caused to turn therewith. Between the bearings a² and a³ I mount a pulley 1
with a recess in its periphery to receive a strap m the tension of the strap on the
pulley being adjusted by a screwed spindle m¹ and hand wheel n as shown at
Fig. 6.
The boss of the pulley is threaded internally so as to form a nut on the screwed
portion of the boring bar c. It will be evident that if the friction strap m were
tightened sufficiently round the pulley 7, the screwed boss would be like a fixed nut
and the boring bar e when rotated would advance at the rate of a thread per revolution
with a single threaded screw. But by adjusting the tension of the strap m to such a
degree as will only feed the bar forward at a rate commensurate to the resistance
encountered by the cutting tool o. a regular feed motion is produced, the pulley
rotating with the bar when the cutting tool has sufficient work in hand, and being
arrested or retarded by the friction strap when the bar can with safety be advanced.

page_text: At
The bracket p which carries the gear to drive the boring bar is clamped to the exterior
of the sleeve i in which the boss of the bevel wheel / runs as already described. This
bracket p is shown separately in end elevation at Fig. 5. and the friction strap and
pulley is also shown separately in section at Fig. 6. The boring bar c is bored for a
certain portion of its length as clearly seen in Figs. 1. and 1ª the hole being placed
excentrically as compared with the centre of the boring bar. Into this hole I
introduce a wedge bar g the outer end being supported by a back centre pin r.
about the point in the length of the boring bar c where the screw thread ends, I insert
-a cutting tool o in a slot made in the bar to receive it. The foot of the cutting tool o
rests on the incline of the wedge bar which latter revolves with the boring bar c.
As the bar is advanced by the screwed boss of the pulley the foot of the cutting
tool o slides up the incline of the wedge bar and consequently the cutting tool is
pushed gradually out of the boring bar. The cutting tool is steadied by a set screw s
which passes through the side of the boring bar and presses upon the side of the tool.
The taper of the wedge is made precisely similar to the intended taper in the hole. For
example the taper which has been given to the hole in the flange coupling shown in section
in Fig. 2 and upon which the tool is supposed to have been mounted corresponds exactly
to the taper of the wedge bar q appearing in Fig. 1. Thus as the work proceeds the
cutting tool o is pushed further and further out of the boring bar c as the bar advances,
the cut becoining heavier at each advance, until when the cutting tool emerges, the
hole has been regularly tapered from front to back as seen in Fig. 2. Screw
pins passing through arms projecting from the bracket a serve to clamp the tool or
apparatus upon the flange couplings.
The wheel d or a handle or pulley used in its place, might be applied to the square
end of the axle of the spur wheel so as to make the driving more direct.
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 general arrangement construction and combination of parts comprising the
improved tool or apparatus for tapering the bolt holes in propellor and other shaft
couplings substantially as described and shown.
(2.) The improved tool or apparatus for the indicated purpose composed of a
bracket a, boring bar c with wedge bar, brake strap, feed nut clamping screws
and driving gear all arranged and acting substantially as described and shown.
Dated this 22nd day of January 1890.
DUTTON & FULTON,
1, St. James Square, Manchester, Agents.