IMPROVEMENTS IN SCREWING, TUBE CUTTING, AND NUT TAPPING MACHINES
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by William Bowker at the Office of the
Commissioners of Patents on the 8th July 1876.
WILLIAM BOWKER, of the City of Manchester, in the County of Lancaster, Engineer.
"IMPROVEMENTS IN SCREWING, TUBE CUTTING, AND NUT TAPPING MACHINES."
The first part of my Invention consists in certain improvements in connection
with the headstocks and die holders of screwing or screw cutting machines for
enabling the dies to be adjusted and contracted and expanded more efficiently and
expeditiously than has hitherto been attained, and also to allow the use of an ending
up cutter during the operation of screwing.
To the back of the bed of the machine I cast a long headstock, into which, when
properly bored, is fitted the body of the die or cutter holder, which is kept in its
place by a screwed plug or washer at the back end of the headstock. In front of
the headstock I cast an additional V guide at each side, and place on these guides
and the surface of the bed a noveable frame carrying a spur or plain wheel having
at the front an inclined ring or cavity which with the outer ends of the dies or
cutters are in contact, the angles of the ends being made to correspond with the
angle of the ring or cavity, and the spur or plain wheel is held in its place by
screwed rings, and when a spur wheel is used it is driven by a pinion in communi-
acation with the driving shaft and pulleys of the machine. In bearings cast or fixed
to the bed of the machine there is a shaft carrying a pinion gearing into a rack at
the bottom of the moveable frame, and in the boss or bearing is fixed a quadrant or
segment graduated by inches and parts or other notation, and to the outer end of
the shaft is fixed a horizontal lever having at one end a weight and connected at
the other end when desired with a treadle.
To the horizontal shaft is fixed a boss and bearing for carrying an upright lever,
one part of which can enter a notch in a projection on the quadrant or segment,
and at the back of this lever there is a spring to keep it in the notch as long as
required; and when the studs or bolts are screwed the required length an incline or
friction bowl secured to a rod in connection with the vice or carriage comes into
contact with the back of the upright lever which throws it out of the notch and
allows the weight to overbalance the horizontal lever and open the dies to enable
the bolt to be removed.
The body of the die holder is nicely fitted into the interior of the boss of the driving
wheel, which with the holder are so held by a key or feather that they both revolve
Price 21

page_text: together but allow the driving wheel with its inclined ring to be removed forwards
and backwards; and in the part of the die holder in which the dies are placed thero
is a circular cavity containing a helical spring in connection with pins for keeping
tho.dies in close contact with the inclined ring. In the interior of the body of the
die holder I place a stock passing through the screwed plug or washer at the back
of the headstock, and having at the front an ending up cutter in a slot or groove
in the die holder and firmly tightened by a set screw so that they both revolve
together; and in the space or chamber between the exterior of the stock and the
interior of the body of the die holder I place a spiral spring and washers, the number
of the washers corresponding with the length of the screwed part of the bolt or pin
to be screwed, ended, or finished up, and in the interior of this ending up stock there
are passages to allow the entrance of water, oil, or soaped, water to the end and body
of the screw as it is being screwed or cut.
:
When the inclined ring is in its extreme backward position the dies or cutters are
expanded to their fullest extent, and they are contracted or pushed towards the
centre to any required extent by bringing forward the moveable frame and inclined
ring by means of the rack pinion and horizontal lever. The pin or bolt to be
screwed is held in a vice or holder, and when the dies are adjusted the pin or bolt
is pushed against the dies, and when revolving motion is given to the inclined ring
and die holder the dies draw the pin or bolt forwards and cut the screw, the ending
up tool at the same time gradually finishing the end; and for cutting tubes in this
machine cutters with single cutting edges are used instead of the screw dies.
For small articles I employ a vice or holder, in which one jaw after being adjusted
is held stationary and the other moved by an eccentric cam or rack and pinion
worked by a lever and link, so that the jaw can be moved to hold the pin or bolt
and released from it casily and expeditiously.
The next part of my Invention relates to machines for screwing or tapping nuts,
and consists in certain improved arrangements for enabling several nuts to be
tapped at the same time by each tap of a series. The taps are held horizontally
in sockets fixed in spur wheels driven by ordinary pulleys and gearing, there being
change wheels to vary the speed of the taps according to their diameters and pitches.
For feeding the blanks to the taps I employ for each tap a spring arm or lever
having a cup or recess, into which the blanks are placed one after another as the
tapping proceeds, there being parallel guides for gently holding the nuts as they are
being drawn forwards by the taps, which guides are capable of being adjusted and
fixed according to the sizes of the nuts. When revolving motion is given to the
taps and the blanks fed up to them they make the blanks one after another into
nuts, which as they are drawn forwards encircle the necks of the taps until there are
sufficient to draw the taps out of their holders and allow them to fall on a riddle or
sieve in a trough. The cuttings and refuse during the process of tapping_fall
through the openings in the riddle into the trough, and the riddle when full is
removed to a cistern containing soaped water, which for a few minutes is boiled by
a jet of steam, after which the riddle is taken out of the cistern and when the nuts
are cold they are ready for packing and sending away.