IMPROVEMENTS FOR CUTTING SCREWS AND OTHER FIGURED ARTICLES ,, LATHES
Year: 1883

page_text: PROVISIONAL SPECIFICATION loft by Frank Wirth at the Office of the
A communication
Commissioners of Patents on the 24th January 1883.
from Heinrich Voigt, Engineer a person resident at Würzburg and Wunibald
Braun of Frankfort on the Main, both in the Empire of Germany
FRANK WIRTH of the firm of Wirth, and Company, Patent Solicitors, at
IMPROVEMENTS IN
Frankfort on the Main in the Empire of Germany
FOR CUTTING SCREWS AND OTHER FIGURED ARTICLES
,,
LATHES
[A communication from
Heinrich Voigt, Engineer a person resident at Würzburg and Wunibald Braun of
Frankfort on the Main, both in the Empire of Germany]
This Invention relates to an automatic universal screw-cutting and turning lathe
which comprises a bed, a head-stock, cutters and operating mechanism, and the
object of the said invention is to produce screws, pins and other articles of different
sizes without loss of time, from bars of different materials such as steel, wrought
iron, brass, cast iron and the like, by means of cams and levers
According to the said Invention the head-stock carries a hollow mandril which
is supported in two bearings and has on its front end which projects beyond the
bearing a self-centreing chuck for holding the rod or bar and causing it to revolve
while it is being manipulated.
The head-stock, can, by means of a lever, be moved towards the cutters in the
tool-holder, whereby the rod or bar is turned as required.
The cutter-head or tool-holder carrying any desired number of cutters which
project inward, revolves in a bearing or box arranged on a rest which can be fixed
or made free by means of a lever.
The said cutter-head can be turned in order to insert a cutter by means of
endless chains, straps, or the like, which are moved by friction or toothed wheels,
or by other suitable means.
The rest carrying the cutter-head can be arranged so as to have only a transverse
movement with regard to the axis of the mandril, or the head stock may some-
times remain stationary and the rest be moved longitudinally with regard to the
0 revolving rod.
The lever which moves the head-stock is actuated by a connecting rod moved by
a cam through a cross-head working in guides.

page_text: The point of connection between the connecting rod and the lever can b
adjusted according to desire by raising and lowering a guide, whereby a reciprocating
motion is imparted to the head-stock within certain limits, on which motion
depends the size of the screws or other articles. This adjustment is effected by the
application of change wheels. Suppose that an article of 20mm in length is to be
constructed, the head stock lever is set in such a manner that the head stock only
moves 10 then this length of 10 m/m would take just as long to turn as is
required for the original length of 20/m. But if, by means of the change
wheels, double the velocity be given to the cam then the articles of half the size will
also be produced in half the time by the same cams without loss of time.
The actuating mechanism consists of a system of cams fixed on a spindle, the
said cams transmitting the prescribed movements to their respective parts by
means of levers.
For various kinds of screws and other articles, different cams are required, they
are therefore arranged to be interchangeable.
The cam-spindle is driven by a worm and wheel, from a second spindle driven
by change wheels on a third spindle and this again is driven from the mandril by
means of straps.
The screw thread is cut either with a common screw-plate or with dies. It is
immaterial when a right handed screw-thread has to be cut, whether the rod
revolves to the right and the cutting arrangement is stationary, or the rod is
stationary and the cutting arrangement revolves to the left, or whether in the case
of a rod revolving to the left the cutting arrangement revolves still quicker to the
left. The screw-cutting is in each case effected by a movement in an opposite
direction.