Improvements in Adjustable Dies and in Stocks for Cutting Threads on Bolts or Tubes and the like.
Year: 1890

page_text: Date of Application, 22nd May, 1890
Complete Specification Left, 15th Sept., 1890-Accepted, 8th Nov., 1890
PROVISIONAL SPECIFICATION.
Improvements in Adjustable Dies and in Stocks for Cutting Threads
on Bolts or Tubes and the like.
We HENRY WESTBROOK and ROBERT BURNS of Woodstock, Ontario in the Dominion
of Canada, Fitters, do hereby declare the nature of this invention to be as follows:-
This invention is designed to facilitate the cutting of threads by means of adjustable
dies so arranged that various sizes of bolts can be cut by the same instrument.
The dies are placed in a circular block which can be attached to a machine or lathe
and driven by power, or can if preferred be used by hand when held in the special
form of stock horeafter described.
The circular block is formed in two halves and these halves are held firm against
lateral pressure by means of pins fitted to enter slots or recesses formed to receive
them.
These pins rest on the ends of four screws which screw into and pass through the
outer edge or periphery of the block, and can be turned by a small screw driver
whereby the pins are inserted further or withdrawn from the interior of the block.
The pins also serve the purpose of adjusting laterally and of steadying the cutting
dies, by each pin impinging against one side of a die and holding it tightly or allowing
it space for lateral movement as desired.
The circular block has a central aperture, radiating from which are four slots in
which the dies slide to and fro. These slots are open on one side, and on the other
have narrow slits in which work small guiding pins attached to the dies. The back
of each die has a recess fitted to receive the ball of a ball-ended screw. This screw also
screws into and passes through the rim of the block, and is adjustable from the outside.
By means of the eight screws thus placed in the rim, four of which regulate the pins
which adjust the dies laterally, and four act directly on the dies from behind, the dies
can be adapted for cutting threads on various sizes of bolts or tubes.
The stock designed to hold the circular block has in its centre a circular enclosure
adapted to receive the said block. This enclosure is open on one side, and is fitted
with a hinged segmental door or cover forming part of the enclosure, and this door
when open allows the block to enter the stock. The door being closed is secured by a
small catch and the stock is ready for use.
The area of the enclosure in the stock is enclosed on one side by a metal plate, and
the inside of the rim of the enclosure is tapered inwards so as to clip the circular block
and hold it firmly in position, the block being also correspondingly tapered so as to fit
securely inside the enclosure.
Bolts or set-screws pass through the stock and secure the block in its proper
position.
Our improved stocks can thus be used by hand in the ordinary way, or the centre
block can be taken out and attached to a lathe or screwing machine.
Dated this 22nd day of Me 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Adjustable Dies and in Stocks for Cutting Threads
on Bolts or Tubes and the like.
We, HENRY WESTBROOK and ROBERT BURNS of Woodstock, Ontario, in the Dominion
of Canada, Fitters, 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 is designed to facilitate the cutting of threads on bolts by machine
or otherwise, and the dies are so arranged and constructed that various sizes of bolts
can be cut by one instrument.
It is chiefly intended for use in screwing machines, but can also be employed in a
lathe, or can be mounted in a suitably framed handstock so as to be used by hand.
I will now proceed to describe the invention with reference to the accompanying
drawings in which
Fig. 1 shews a plan view of the hand stock for hand screwing, in the partly open
position.
Fig. 2 is a front view in perspective of one half of the head stock a.
Fig. 3 is a back view of the same shewing slots and pins on cutters.
Fig. 4 is a view in perspective of the die or cutter b.
Fig. 5 is a sectional plan of the head stock'a, shewing the travelling pins or
adjusting set screws f¹³, f.
It will be seen that the circular head-stock a, is formed in two halves and has a
central aperture radiating from which are the four recesses c, which are fitted to
receive the four steel cutting dies b, each of which has a concave segmental face d,
which bears the thread, and that all four dies are arranged to operate simultaneously
on the bolt to be cut.
Behind or beneath each is the pin or sturte, which travels in a slot o, in the
back of the headstock a, as shewn in Fig. 3, and which ensures the advance of the
die b, in a true radial line while allowing the necessary lateral movement. The
required amount of lateral adjustment and support is provided for and regulated by
eight cross set screws or travelling pins ƒ¹, ƒ³, which pass through the rim of the head
stock and bear against the dies b, at a point near the cutting face as shown in Fig. 5.
Two of these travelling pins are provided for each die, and their inner ends terminate
nearly or quite opposite to each other on the alternate sides of the die. Each pin is
enlarged at its outer end where it carries a thread, which engages with a thread in the
rim of the stock, and it has a nicked head which enables it to be turned by a turn-
screw and thus tightened or slackened so as to hold the die firmly in the required
position. The forward and backward adjustment of each die is effected by the ball
headed screws i, which are screwed through the back of the recess c, and also nicked
at the outer end so as to allow of its being operated from outside. When required
for machine screwing a cap-plate, in two halves can be fitted over the open side of the
recesses c, so as to enclose and protect them. This cap-plate can be furnished with
round-anded slots so as to pass over screw heads or studs tapped into the stock, and
fasten under them when slightly turned round.
The dies b, are cut with the centre of the die towards the centre of the tap. They
are then swung back till the cutting edge is dath in advance of the centre.
.
In consequence of this conformation they act more as a turning tool on the work,
instead of grubbing it off as is the case with the ordinary dies. By this means friction
is diminished and they can be worked with less power. They leave a clean solid
thread much superior to threads which are forced up by friction in the usual way.
Our improved dies need no filing on the back or front. As they wear they can be
up to their work by the set-screw t.-One of these dies will screw bolts from fg to
one inch by simply adjusting the set screws.
set
There being no bolt heads projecting, our improved dies can screw closer to the
head of the bolt than the dies now in use, which is an advantage in many cases.

page_text: In order to use the headstock a, for screwing by hand, a special form of hand-stock
is employed which is shewn in Fig. 1. This has a circular box or enclosure k in the
centre, one side of which is enclosed by a metal plate g. The rim of the enclosure k
is slightly tapered inwards and the periphery of the headstock a, is slightly tapered
outwards, so that there is no tendency to work out, or to fall out when the chamber is
opened. This centre enclosure k has a fixed half connected at either side to the
handles, the other half being hinged on one side and forming the door k¹ shewn partly
open in Fig. 1, which when fully open admits the headstock a, to enter the handstock.
This door when closed is secured through the slot m, by a small wedge shaped
hinged catch n, entering from the opposite side, which draws the door k, tightly
closed, so as to clip and wedge the headstock a, firmly in position. Set screws t, passing
through the rim of the handstock fasten each half of the headstock to its corresponding
half of the handstock. A similar arrangement without the handles can be used if
preferred in fitting up the head stock for use in a lathe.
Our invention is readily applied to the present screwing machines, by a slight
modification of the existing die-holder.
In the case of extra long dies being employed additional lateral support can be
obtained by the use of square headed set screws or studs inserted in the side of
the die.
Having now particularly and ascertained the nature of our said invention,
and in what manner the same is to be performed, we declare that what we
claim is :-
11
1. In a head-stock or block for cutting threads the special form and arrangement
of the head stock and dies, whereby friction is lessened, and the die can be recut when
worn, instead of becoming useless, as herein described and set forth.
2. In a headstock for cutting threads, the mode of adjusting and setting up the dies
to their work by the set screws or travelling pins f¹f and the ball head screws i, and
pins and slots e, o, as herein explained and set forth.
3. The improved hand-stock for using our improved head-stock, and the mode of
fastening the headstock therein and of wedging the same securely in position as herein
described and set forth.
Dated this 15th day of September 1890.
S. S. BROMHEAD,
97, Newgate Street, London, E.C., Patent Agent.