IM- PROVEMENTS IN OR APPLICABLE TO SCREWING MACHINES
Year: 1876

page_text: LETTERS PATENT to William Kendall, of the Firm of Kendall and Gent, of
Salford, in the County of Lancaster, Machinists, for the Invention of "IM-
PROVEMENTS IN OR APPLICABLE TO SCREWING MACHINES."
ed the 22nd August 1876, and dated the 29th February 187
PROVISIONAL SPECIFICATION left by the said William Kendall at the Office
of the Commissioners of Patents on the 29th February 1876.
WILLIAM KENDALL, of the Firm of Kendall and Gent, of Salford, in the County
of Lancaster, Machinists. "IMPROVEMENTS IN OR APPLICABLE TO SCREWING
MACHINES."
This Invention relates more particularly to the form of screwing machine for
which Her Majesty's Letters Patent, bearing date the Thirty-first day of January,
One thousand eight hundred and sixty-seven, and numbered 269, have been granted
to a certain Edward Thomas Hughes. In the said machine the screwing dies are
mounted radially in a revolving die holder, and are arranged to be set up and with-
drawn by the action of a cam ring which is fitted to slide upon the said die holder.
The said cam ring was slid in one direction or the other by means of a hand lever
when the dies were to be moved into or withdrawn from action.
The object of my said Invention is to effect the sliding back of the said cam to
withdraw the dies from action by self-acting means, and to this end I form a cam
shaped incline on the boss of the said cam ring, and I arrange an antifriction bowl or
stud to be moved into position to serve as a fulcrum upon which the said incline
may act to effect the said sliding back of the cam ring.
In an arrangement, which I now consider to be suitable, the said bowl is mounted
on a stud, which is fixed to a lever, which is fitted to swivel so as to move the said
stud to-and-fro. One end of the said lever is connected by means of a link with a
crank fixed or formed on a shaft on which is fixed or formed a spur pinion which
gears with a sliding rack. A spring tends to draw the said rack in one direction,
and a detent holds the said rack whilst the screwing is proceeding. When the
required length of screw has been cut an adjustable stop moves the detent, whereby
the rack is released and is drawn back by the spring. The said movement of the
[Price 2d1

page_text: rack causes the shaft to revolve to some extent, and the crank moves the said lever
over into the position which will present the said bowl as a fulcrum upon which
the incline on the said cam ring may act as aforesaid. I prefer to so proportion
the parts as that the said shaft performs about half a revolution when moving the
lever, in order that when at rest the crank may be in the most favourable position
to resist the thrust caused by the strain upon the said bowl. When the blank holder
is moved back to receive a fresh bolt the carriage draws forwards the said rack until
it is again held by the detent, the said bowl being thereby caused to slide the said
cam ring forwards, and to maintain it in the forward position.
Although I have only mentioned one form of screwing machine, my Invention
may be found to be applicable to other forms of screwing machines having revolving
screwing dies.