IMPROVEMENTS IN SCREWING MACHINES
Year: 1882

page_text: LETTERS PATENT to Samuel Dixon of the firm of Kendal and Gent of
Salford in the County of Lancaster Machine Tool Makers for an Invention of
IMPROVEMENTS IN SCREWING MACHINES
"
"
PROVISIONAL SPECIFICATION left by the said Samuel Dixon at the Office
of the Commissioners of Patents on the 19th December 1882.
SAMUEL DIXON of the firm of Kendal and Gent of Salford in the County of
Lancaster, Machine Tool Makers, "IMPROVEMENTS IN SCREWING MACHINES
"
My Invention relates to the class of machines having in each case a sliding
collar which is moved to and fro in order to advance or retract the cutting dies as
for example to the Brown screwing machine. In the machine as ordinarily
constructed the said sliding collar is moved by means of a hand lever and in the
larger machines this necessitates the exertion of some degree of force on the part
of the workman. To obviate this I employ a movable abutment which acts upon
curved or inclined faces on the collar so that the said collar is slid either in one
direction to advance the dies or in the other to re-tract them according to the
position of the abutment. For an abutment I employ a crank which is formed or
fixed on a shaft which can be turned over to the extent of half a revolution. The
said crank is provided with a bowl or projection which serves as an abutment.
The arrangement is such as that in either position the crank is on the dead centre
so that the thrust of the collar does not tend to turn the crank. I may vary the
method of shifting the abutment so long as it is locked or adapted to resist the
thrust of the collar. In some cases and especially in the cases of the smaller
machines I arrange for the abutment to be shifted or turned over self-actingly to
retract the dies as for example I cause the sliding carriage of the machine to
release a rack bar which is acted upon by means of a spring or weight and imparts
the required movement to a wheel or segment upon the crank shaft.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Samuel Dixon in the Great Seal Patent Office on the 19th June
1883.
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"
SAMUEL DIXON of the firm of Kendal and Gent of Salford in the County of
Lancaster Machine Tool Makers 'IMPROVEMENTS IN SCREWING MACHINES
My Invention relates to that class of machine having in each case a sliding
collar which is moved to and fro in order to advance or retract the cutting dies as
for example to the Browns screwing machine. In the machine as ordinarily
constructed the said sliding collar is moved by means of a hand lever and in the
larger machines this necessitates the exertion of some degree of force on the part
of the workman. To obviate this I employ a movable abutment which acts upon
curved or inclined faces on the collar so that the said collar is slid either in one
direction to advance the dies or in the other to retract them according to the
position of the abutment. I prefer to employ a crank which is formed or fixed on
a shaft which can be turned over to the extent of half a revolution. The said
crank or a part moved by the said crank.is provided with a bowl or projection
which serves as an abutment. The arrangement is such as that in either position
the crank is on the "dead centro so that the thrust of the collar does not tend to
turn the crank. In some cases and especially in the cases of the smaller machines
arrange for the abutment to be shifted or turned over selfactingly to retract the
dies.
"
In order that my invention may be fully understood I have attached hereunto a
sheet of drawings made to a scale of about three inches to the foot and marked
with letters of reference. In the said drawings Fig 1 represents an end elevation
and Fig 2 a side elevation of so much of a "Browns" screwing machine as made
by Messrs Kendal and Gent of Manchester as is necessary to be represented in
order to illustrate the application of my invention. In the said Figs a is
the screwing head containing the screwing dies, and b is the collar which
slides upon the spindle c which revolves in the headstock. When the said
collar is slid in one direction it acts in the usual manner upon parts which
advance all the dies simultaneously into their screwing positions and when
slid in the other direction retracts all the dies so that they cease to act.
The said collar is separately represented by Fig 3 wherein b¹, 62, are pro-
jections formed with inclined faces which act upon an abutment to effect the
sliding movement of the collar the projection 6' acting upon the abutment to shift
the collar outward from the screwing head in the direction indicated by the arrow
in Fig 1 and the abutment 62. acting to shift the collar inward. In the example
the said abutment consists of an anti-friction bowl d which revolves upon a stud
carried by a sliding block e these parts being also represented in plan in Fig 4.
The block e is fitted to slide to and fro in the same direction as the collar b being
fitted in a slide planed in a part f which is cast upon or fixed to the head stock.
The said block is inoved by means of a crank pin which is upon a shaft g which is
fitted to rock in a bearing each movement of this crank shaft being 'limited to one
half of a revolution in either direction so that the crank pin may be brought into
position either on one side or the other of the axis of the shaft but when at rest is
always in or about in horizontal line with the said axis. It will be seen that at
each half revolution of the crank shaft the block e will be moved horizontally the
throw of the crank being calculated to move the said block the distance required to
effect the requisite movement of the sliding collar. In the drawing the crank pin
is to the right of the crank shaft axis the sliding collar being in its inward position
and it will be seen that any pressure of the projection 62. upon the bowl & will not

page_text: move the block e for the reason that the crank pin being upon the "dead centre"
is in a position to withstand the thrust. Supposing the crank to be turned half
over into position on the left of the axis of the crank shaft the incline on the
projection b¹ would bear upon the bowl d and as the crank pin would again be on
the "dead centre" the said bowl would be sustained against the thrust and the
collar be compelled to slide outward in the indicated direction. As ordinarily
constructed this movement would have the effect of retracting the dies. On the
crank shaft being half rotated so as to turn back the crank into the position
indicated in the drawings the collar will be moved inward to advance the dies into
their acting positions. The shaft may be provided with a simple handle or hand
wheel but in the example in addition to a handle h it is provided with a chain
wheel which is geared by means of a pitch chain with a second chain wheel j.
The wheel i is secured to the handle by means of a removable screw or bolt.or a
suitable locking device is adapted so that when desirable the crank shaft, can be
turned by means of the handle the chain wheel not revolving. The wheel j is fixed
upon the outer end of a shaft k upon which is also fixed a pulley 7 from the
periphery of which pulley is suspended a weight m. which tends to turn the shaft
in the indicated direction. Upon the same shaft is fixed a rack pinion n which in
the example is formed upon the wheel j and gears with a sliding rack bar o which
is connected with a sliding rod p. A catch upon a lever r enters a notch in the
rack bar and keeps the parts in the positions indicated in Fig: 1 during the screwing
of a bolt or other object. When the screwing has been effected to the determined
extent an arms upon the carriage comes into contact with an adjusted collar t
upon the rod p and slides the said rod in the indicated direction whereby an
incline u upon the rod is caused to lift the end of the catch lever r so as to release
the rack bar. The shaft m is then at liberty to revolve and makes half a revolution
which is communicated by the chain-wheel and chain to the crank shaft and the
collar b is shifted in the indicated direction so as to retract the dies during the next
revolution or part of a revolution of the screwing head. When the carriage is
moved back the arm 8 acts upon a second adjusted collar and slides back the rod
and rack bar thereby turning back the shaft m and effecting the return movement
of the sliding collar required to advance the dies or if preferred the said movements
may be effected by turning the crank shaft by hand. I may use a spring instead
of the weight. In order to shift the collar b within the next half a revolution of
the screwing head immediately following the movement of the crank shaft I provide
the said collar with two sets of inclined projections on opposite sides of the axis
but the number of such sets may be varied. I do not confine myself to the use of
the crank shaft to shift the abutment so long as an abutment is used which can be
quickly shifted horizontally and which will withstand the thrust of the collar. I
may dispense with the sliding block e in which case the inclines on the sliding
collar would act directly upon the crank pin or upon a bowl mounted thereon.
The arrangement may also be varied by mounting the bowl d upon a vibrating
lever or arm which would be shifted to and fro by means of the crank. I may use
spur or worm gearing or other arrangements in lieu of the chain wheels and chain
or may not provide self-acting means for turning the crank over and may substitute
an excentric for the crank.
Having now fully set forth and indicated the nature of my said invention and
the manner in which I carry the same into practical effect I would have it to be
understood in conclusion that I claim :-
First the combination of parts of a screwing machine arranged and acting
substantially as and for the purposes set forth and indicated hereinbefore and in
and by the accompanying drawings.
Secondly the surfaces inclined in opposite directions upon the sliding collar of a
screwing head acting upon an abutment which can be moved in the direction of
sliding movement of the said collar from one position to the other to shift the
sliding collar towards or from the screwing head substantially as and for the purpose
set forth and indicated. .

page_text: t:
Thirdly the employment of a crank or excentric arranged to be turned over by
a half revolution in either direction so as to constitute or to sustain an abutment
to receive the thrust of the said sliding collar and to effect the sliding movement of
the same substantially as set forth and indicated.
: And lastly connecting the crank shaft or part which moves the abutment with
parts which are acted upon by means of a weight or spring. 15 so that when a rack
bar is released the weight or spring effects the movement of the abutment
substantially as and for the purpose set forth and indicated.
In witness whereof I the said Samuel Dixon have hereunto set my hand
and seal this eighteenth day of June in the year of our Lord one thousand
eight hundred and eighty-three¨
Signed, sealed and delivered
in the presence of
EDWARD K. DUTTON
41 John Dalton St. Manchester.
(Agent for the Patentee)
SAMUEL DIXON. (L.S.)