An Improved Jaw for the Face Plates or Chucks of Turning Lathes.
Year: 1898

page_text: Date of Application, 24th May, 1898-Accepted. 9th July, 1898.
COMPLETE SPECIFICATION.
An Improved Jaw for the Face Plates or Chucks of Turning
Lathes.
We, EDUARD EKERDT, Iron-turner, 21, Pfluggasse, Biberach, Württemburg, and
CARL ZELL, Brewer, of 21, Pflugstrasse, Biberach, Württemburg, 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 :-
With the jaws of face plates or chucks of lathes as at present constructed it is.
if one wishes to take off smaller objects for the purpose of securing larger
necessary,
ones, to turn round the jaws in order that their angles, which serve to hold the
articles tightly in place, may come to an outside position so that the objects of greater
diameter can be inserted. In order to turn the jaw one must unscrew its spindle,
which enters the face plate and which is for the purpose of holding and moving the
jaw, entirely out of the screwed part of the jaw and only then can the jaw be taken
out of the face plate and turned round. The spindle requires to be screwed in again
to secure the jaw. To avoid this waste of time and tiresome manipulation is the aim
of the present invention and with this object the jaw is made in two parts instead of
one.
And in order that our said invention can be properly understood we have hereunto
appended an explanatory sheet of drawings, whereon,
Fig. 1 is a side view, partly in section, of an old but somewhat altered face-plate
jaw, whilst,
Fig. 2 is a side view of the new part which forms the subject matter of our
invention.
Fig. 3 is a back view of the new part, and
Fig. 4 is a front view of the old jaw.
As aforestated the new jaw consists of two parts A, B. The part A, which is a
slightly altered form of the usual jaw, consists of the short centre piece a, which is
provided with the segments c, and secured in the corresponding slot of the face plate
in which it is guided as usual. The stud d, with the nut and washer e, serves to
secure the jaw in the usual manner. The screwed spindle f, passing through the
nut b, serves also, in the usual manner, to radially move the jaw on the face plate.
At the front of the centre piece a a hole h is bored and this hole, as shown, is
widened out, at i, so as to form a circular recess which is rectangular in cross-
section. Two grooves o, cut at points diametrically opposite, lead from the recess to
the outside. The new part B of the jaw, which is provided with faces n, m and k to
secure the work, has, at its back, a round stud h¹ which latter is provided, at its end,
with two projections g arranged diametrically opposite one another. The part B is
further provided with two faces which are concentric with the stud h¹ and which,
when bearing against the inner faces of the segments c of the part A, serve to support
the part B. The mode of securing the part B to the part A is as follows, namely;-
it is first turned, for example, into the horizontal position, so that the projections g
may enter, through the grooves o, into the ring groove or recess i and when this has
been done it is again turned, for example, into the vertical position so that the faces
may bear against the inner surfaces of the segments c and the part B lie parallel to
the part A. The whole jaw (A and B) is now ready for use and if one desires to secure

page_text: a piece of work between the surfaces kor m of the four jaws of the face plate (the
outer surface q of the part B of each jaw, bearing against the exterior segment c) the
pressure is put on by the screw ƒ as usual. The projections g, owing to the fact that
they have been turned through say an angle of 90°, prevent the part B coming apart
from A. Should the movable jaw, for any well known reason, require to be turned,
all that is necessary is to turn the part B through an angle of 180° on the pin h¹,
whilst the part A can be allowed to remain in its proper position on the face plate.
Having now particularly described and ascertained the nature of our said invention
and in what manner the same is to be performed we declare that what we consider
novel and desire to claim is :-
In jaws for the face-plates or chucks of turning lathes, making the usual jaw A with
a recess and entering grooves o and combining with it a separate part B which is
provided with a pin h¹ having projections g whereby it can be locked securely and yet
movably in the recess i of the jaw A, substantially as and for the purpose set forth.
Dated this 1st day of May 1900
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.