Improvements in or connected with Tapping Machines.
Year: 1891

page_text: Date of Application, 28th Nov., 1891
Complete Specification Left, 26th Aug,, 1892-Accepted, 8th Oct., 1892
PROVISIONAL SPECIFICATION.
Improvements in or connected with Tapping Machines.
1, RICHARD HENRY LEA, of Stoke Green, Coventry in the County of Warwick
Machinist, do hereby declare the nature of this invention to be as follows :-
My invention relates to improvements in or connected with tapping machines.
The ordinary type of tapping machine (having automatic reversing gear) is of
similar form to a lathe headstock; the two pulleys of such a machine driven in
opposite directions are placed in the centre of, or between the two bearings, the
spindle being then allowed to move slightly endwise to come into gear with one or
other of the pulleys as desired.
This arrangement is somewhat expensive, and is moreover open to the more
serious objection that the spindle has to sustain the whole strain of the two driving
belts and it thus becomes necessary to make the spindle much heavier than is
requisite for driving the tap. The spindle being moved by pressing the work in
hand to or fro, it is obvious that the weight and friction of the spindle must be
detrimental, and especially so in the case of small holes and fine screw threads.
In order to overcome these various imperfections, I construct tapping machines
according to my invention substantially as follows:
A single casting is made, consisting of a base plate, upon which is set up a single
rib web or standard having a boss projecting on each side thereof, and the two
bosses are in line with each other, a hole being bored through the two in which the
spindle is located.
The pulleys are made to run on the said bosses, the latter thus taking all strain
of the belts, and upon each end of the spindle is a suitable cam, snail, or clutch, to
gear into one or other of the pulleys.
In cases where countershafts, with fast and loose pulleys are not used, I provide
for the spindle being locked in its central position and out of gear with both cams
or clutches whereby the changing of taps &c., is greatly facilitated.
A drill may be added at opposite end of spindle to that in which the tap is placed
thus enabling the operator to drill and tap with only one handling of the work the
drill being then driven by the same pulley which imparts the quick return motion
to the tap.
It is obvious that various holders, "jigs," slide, and lever feeds &c., may be used
in conjunction with the machine and to suit the particular work for which they may
be designed.
By constructing the machine substantially as described I secure a very light and
sensitive spindle, simplicity of parts and consequent cheapness of manufacture.
Dated this 28th day of November 1891.

page_text: Improvements in or connected with Tapping Machines.
I, Richard HenRY LEA, of Stoke Green, Coventry, in the County of Warwick,
Machinist, 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 improvements in or connected with tapping machines.
The ordinary type of tapping machine (having automatic reversing gear) is of
similar form to a lathe headstock; the two pulleys of such a machine driven in
opposite directions are placed in the centre of, or between, the two bearings, the
spindle being then allowed to move slightly end wise to come into gear with one
or other of the pulleys as desired.
This arrangement is somewhat expensive, and is moreover open to the more
serious objection that the spindle has to sustain the whole strain of the two driving
belts, and it thus becomes necessary to make the spindle much heavier than is
requisite for driving the tap. The spindle being moved by pressing the work in
hand to or fro, it is obvious that the weight and friction of the spindle must be
detrimental, and especially so in the case of small holes and fine screw threads.
In order to overcome these various imperfections, I construct tapping machines
according to my invention substantially as shewn by the accompanying drawings
hereafter referred to in the following description.
Fig. 1 shews the apparatus in vertical longitudinal section.
Fig. 2 shews a detached face view of the return cam, and
Fig. 3 is a similar view of the driving cam.
Similar letters refer to like parts in the several figures.
A single casting is made, consisting of the base plate A, upon which is set up a
single rib, web or standard A', having a boss A2 A3 projecting on each side thereof,
and the two bosses A2 A2 are in line with each other, a hole being bored through
the two, in which the spindle B is located.
The pulleys CD are made to run on the said bosses, the latter thus taking all
the strain of the belts; and upon each end of the spindle is a suitable cam, snail,
or clutch, E F, to gear into one or other of the pulleys C D. G is a spring which
may be employed for bringing the return cam into action mechanically.
In cases where countershafts with fast and loose pulleys are not used, I may
provide for the spindle being locked in its central position and out of gear with
both cams
or clutches, whereby the changing of taps &c. may be greatly
facilitated.
A drill may be added at opposite end of spindle to that in which the tap is
placed, thus enabling the operator to drill and tap with only one handling of the
work, the drill being then driven by the same pulley D which imparts the quick
return motion to the tap.
It is obvious that various holders, "jigs," slide, and lever feeds &c., may be used
in conjunction with the machine, and to suit the particular work for which they
may be designed.
By constructing the machine substantially as described, I secure a very light and
sensitive spindle, simplicity of parts and consequent cheapness of manufacture.
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. In tapping machines, the combination with a spindle B carrying the operating
tools and provided with cam clutch devices E and F, of coacting pulleys CD,
mounted and running on bosses A2 A2, through which bosses the spindle BĎ passes,

page_text: the bosses A' A' being formed or provided with standard and base, all acting
substantially as and for the purposes herein described.
2. In tapping machines, the frame or support, composed of a base-plate A, a
web or standard A', with side projecting bosses A A', for carrying and forming
bearings for pulleys, and a hole bored axially through the bosses to receive a
spindle B, substantially as set forth.
3. The tapping or combined tapping and drilling machine, all constructed and
acting substantially as and for the purpose herein described with reference to the
accompanying drawings.
Dated this 26th day of August 1892.
BREWER & SON,
33, Chancery Lane, London, Agents for Applicant.