Improvements in Screw Cutting Machines.
Year: 1892

page_text: Date of Application, 28th July, 1892
Complete Specification Left, 20th Apr., 1893-Accepted, 20th May, 1893
PROVISIONAL SPECIFICATION.
Improvements in Screw Cutting Machines.
1, THOMAS BENJAMIN SMITH of 155 Victoria Road, Aston juxta Birmingham
in the County of Warwick, Screw Maker, do hereby declare the nature of this
invention to be as follows:-
This invention has reference to hand screw cutting machines but is equally
applicable to automatic screw cutting machines, the objects of which are to simplify
the stop action and make the machines more effective.
up
My improvements consist in hinging or pivoting to the lever bar (which actuates
the wedge or jaws carrying the screwed dies for regulating the pitch of thread to
be cut) a short pin or stud which I call a plunger, the said plunger works and
down through a hole or slot formed in the short arm which carries or supports the
screwed die jaws. Hinged to the said short arm and directly over the hole or slot
through which the plunger works, is a flat lever which I call a stop piece. When
the machine is not in action the lever bar causes the plunger to protrude through
the hole or slot formed in the short arm which carries the screwed die jaws,
thereby lifting the stop piece in contact with the back end of the main spindle and
completely blocking the said main spindle from traversing until released by lifting
the lever bar.
By the use of my improvements 1 am enabled to dispense with an extra lever
bar and other accessories, the machine is much cheaper to make and more durable
and effective.
Dated this 95th dor of July 1892.
THOMAS BENJAMIN SMITH.
COMPLETE SPECIFICATION.
Improvements in Screw Cutting Machines.
1, THOMAS BENJAMIN SMITH, of 155 Victoria Road, Aston juxta Birmingham
in the County of Warwick, Screw Maker, 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 has reference to hand screw cutting machines but is equally
applicable to automatic screw cutting machines the objects of which are to simplify
the stop action and make the machines more effective."
In order that my invention may be clearly understood I have annexed the
accompanying sheet of drawings illustrative thereof.
Fig. 1 is front elevation of a screw cutting machine headstock, and
Fig. 2. is plan of same.
A is the lever bar which actuates the wedge or jaws B carrying the screwed
dies C for regulating the pitch of thread to be cut. Hinged or pivotted to the
said lever bar A is a short pin or stud D which call a plunger. The said
plunger D works up and down through a hole or slot formed in the short arm E
which carries or supports the screwed die jaws B. Hinged to the said short arm E
and directly over the hole or slot through which the plunger D works, is a flat
hinged lever F which I call a stop piece.
In order to prevent the main spindle G from traversing whilst the screw which
is being operated upon is pointed the lever bar A is lowered to the position as
shewn in the drawings thereby causing the plunger D to lift the stop piece F in
contact with the collar H, which said collar H is secured to the spindle G, by which

page_text: means the said spindle G is effectually blocked or prevented from traversing.
When desired I may dispense with the stop piece F and so form the plunger D
that when the lever A is lowered the said plunger D will come in contact with the
collar H thereby forming a stop piece and effectually blocking or preventing the
spindle G from traversing. Or the plunger D and stop piece For equivalent may
be arranged so as to operate from the top of the said spindle G.
By the use of my improvements I am enabled to dispense with an extra lever
bar and other accessories, the machine is cheaper to make and more durable and
effective.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I would have it understood
that I do not confine myself to the exact details as hercin shewn and described as
they may be varied, but what I wish to claim is :-
In a screw cutting machine the means substantially as herein shewn and described
or their equivalent for blocking or preventing the spindle G from traversing whilst
the screw or other object is pointed, turned or otherwise operated upon.
Dated this 19th day of April 1893.
THOMAS BENJAMIN SMITH.