An Improved Screw-cutting Apparatus for Lathes and Screwing Machines.
Year: 1890

page_text: Date of Application, 8th Sept., 1890
Complete Specification Left, 8th June, 1891-Accepted, 11th July, 1891
PROVISIONAL SPECIFICATION.
An Improved Screw-cutting Apparatus for Lathes and Screwing
Machines.
We, HENRY WESTBROOK and ROBERT BURNS, Fitters, both of Woodstock,
Ontario, in the Dominion of Canada, do hereby declare the nature of this invention
to be as follows:-
This invention is designed to effect improvements in the cutting arrangements of
screwing-machines used for cutting threads on bolts, and is also applicable to lathes
used for similar purposes.
It consists of a horizontal mandril the rear end of which is attached to the lathe
or screwing-machine so as to operate when the machine is set in motion.
On the front end of the mandril is screwed a vertical face plate with hole in
centre having in its face T or dovetail shaped slots into which slide the corre
spondingly shaped lugs of an annular disk, forming a die-block. This die-block
is divided into two halves, which have spiral springs inserted in holes formed on
their contiguous edges, the function of which springs is to keep them apart.
At the rear end of the mandril is a cross har or pivot plate which is keyed
or fixed to the mandril, and at each of its ends forms a pivot joint for two
levers extending along the mandril, the fore-ends of which levers pass through
slots in the face plate and terminate in recesses in the die-block. The rear
ends of these levers have curved hooks which are constructed to press against
the sloping sides of the cone-head collar in such a manner that when the face-
plate is screwed further on to the mandril, the cone-head of the collar opens
the rear ends of the two levers and thereby closes or presses together their
fore-ends and also therewith the two halves of the die-block operated by them,
and thus the proximity of the dies is regulated by screwing to or fro the faceplate
on the end of the mandril. On the face of the die-block are attached three or more
small metal boxes or dic-holders which contain the cutting dies. These die-holders
vary in length from about two inches to three inches and in width from about half
an inch to one inch, and are pivoted on set-screws passing through lugs on their
rear end. Lugs with slots in which another set-screw is inserted are attached to
one side so as to limit the amount of lateral travel the die-box can make, and an
adjustable stop is fixed near the other side in which is a set screw pointing towards
the side of the die-holder, so as to stop it in any required position. The steel die
itself lies within the die-holder and has in its rear end a nearly circular recess in
which works the head of a ball headed screw, the shank of which passes through
the rear end of the die-holder, and is nicked so that it can be turned with a turnscrew
and the exact longitudinal position of the die adjusted. In one side of the die-
holder is also another small set-screw which bears against the die laterally and
holds it tight inside the holder.
This arrangement of adjustable dies and die-holder has many advantages, and
will be found of great practical value.
Dated this 8th day of Santambou 1800.

page_text: COMPLETE SPECIFICATION.
An Improved Screw-cutting Apparatus for Lathes and Screwing
Machines.
We, HENRY WESTBROOK and ROBERT BURNS, Fitters, both of Woodstock,
Ontario, in the Dominion of Canada, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described aml ascertained in and by the following statement :-
This invention is designed to effect improvements in the cutting arrangements
of screwing machines used for cutting threads on bolts, and is also applicable to
lathes and for similar purposes.
We will now proceed to describe the apparatus with reference to the
accompanying drawings, in which Fig. 1 shews a side elevation of the whole, but
without the cutting boxes in front. Fig. 2 shews a front elevation of the die-block
with the cutters in position or indicated by dotted lines. Fig. 3 shows a longitudinal
sectional elevation of one of the cutting boxes with the entters inside.
The invention consists of a horizontal mandril a, the rear end of which is
intended to be attached to the lathe or screwing machine, so as to be operatist when
the machine is in motion.
The front end of the mandril is screwed at k, into a hole in the centre of a
vertical faceplate b, which has in its fac T or dovetailed shaped slots, into which
slide the correspondingly shaped lugs of an annular disc c, which forms a die-
block.
This dic-block is divided into two halves e, c', which have one or more spiral
springs d, inserted in holes formed on their contiguous edges, the function of which
springs is to keep the halves of the die-block apart.
At the rear end of the mandril is a cone head collar e, and near the centre of the
mandril is a cross-bar or pivot-plate, which may or may not be keyed or fixed to
the mandril, and each of its ends forms a pivot joint g, for two levers extending
along the mandril a, the fore ends of which levers pass through slots in the face-
plate and terminate in recesses i, in the die-block. ´ The rear ends of those levers
have curved hooks which are constructed to press against the sloping sides of the
cone-head collar e, in such a manner that when the face-plate is serowed further on
to the mandril at k, the cone-head of the collar opens the rear ends of the two levers
and thereby closes or presses together their fore-ends, and also therewith the two
halves of the die-block c, c', operated by them and thus the proximity of the dies
regulated by screwing to and fro the face-plate on the end of the mandril at k.
On the face of the die-block are attached three or more small metal boxes or die
holders, which contain the cutting dies m.
These die-holders vary in length from about two inches to three inches and in
width from about half an inch to one inch, and are pivotted on set screws pressing
through lugs on their rear end.
Lugs o, with slots in which another set scrow is inserted are attached to one or
both sides so as to limit the amount of lateral travel the dic-box can make, and
an adjustable stop is fixed at one side, in which is fixed a set-screw, pointing
towards the side of the die-holder so as to stop and support it in any required
position.
The steel die m, lies within the die-holder, and has in its rear end a nearly
circular recess s,
in which works the hond of a ball, or cheese headed screw, the
shank of which passes through the rear end of the die-holder, and is nicked so that
it can be turned with a turnscrew, and the exact longitudinal position of the die
adjustod.
In one side of the dic-holder is also another small set-screw which bears against
the die laterally and holds it tight inside the holder.

page_text: This arrangement of adjustable dies and die-holders has many advantages and
will be found of great practical value.
Having now particularly described 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:-
1. In a screw cutting apparatus for use in screwing-machines or lathes, the die-
block c, the dic-holders with their dies m, as herein described and set forth.
2. In a screw cutting apparatus as aforesaid the combination and arrangement
of the dic-block c and dic-holders with the mandril a, the levers and the collar
as hercin explained and set forth.
Dated this 8th day of June 1891
e,
S. S. BROMHEAD,
97, Newgate Street, E.C., Patent Agent.