Improvements in Screw and Nut Mechanism.
Year: 1898

page_text: Date of Application, 10th Nov., 1898-Accepted, 7th Jan., 1899
COMPLETE SPECIFICATION.
Improvements in Screw and Nut Mechanism.
I, ADOLF GOSSER, of 39, Hohler-Weg, Iserlohn, Westphalia, in the German
Empire, Mechanician, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to improvements in machine tools such as screw presses
and the like, and consists in the application of screw threads of various pitch
to alter the relation of the power transmitted.
The advantage obtained is that when the transmission is altered while the
machine is at rest, the same machine may be used for purposes, requiring different
powers, and may thus be employed for heavy or light work.
Further the alteration of the transmission may be effected during operation,
so that, for instance, the machine is started at high velocity and before the
screw or tool reaches the work-piece, the other transmitting screw is engaged,
whereby the active force is utilized most effectively.
In order that this invention may be the better understood, I now proceed
to describe the same, reference being had to the accompanying drawings and
to the letters and figures marked thereon.
Figure 1 illustrates the device, partly in elevation and partly in section, the
two screws not being coupled.
Figure 2 illustrates the device when the two screws are coupled.
Figure 3 is a view corresponding to Figure 2, but at an angle of 90° therewith.
The lower arme of the frame of the machine carries as usual a screw guide f.
The lower part of the machine is omitted as non-essential for the illustration
of this invention. The guide f is slotted in the usual manner and provided with
oil ducts; the construction of this part is of no importance to the character of
my invention.
The screw B of the machine has a screw thread of high pitch and runs in a
bush or sleeve A having inner and outer screw threads. The inner screw thread
of the bush or sleeve A engages with the screw thread B, and the outer screw
thread of the former, which is of lower pitch than the latter engages in an inner
screw thread of the boss of the upper arm of the machine.
The sleeve or bush A carries a flange a having a suitable recess on the upper
face with which engages a corresponding projection of a nut or adjustable ring b
which can be adjusted on the screw B at various heights by means of the set
screw h.
The collar a of the bush or sleeve A has a slot in which is situated a sliding
piece a resting on the plate m of the frame of the machine and which is forced
o rise relatively to the slot when the bush A descends. The sliding piece x thus
passes into a corresponding slot of the nut or ring b whereby the parts a and b
re coupled. When the screw rises, the pin y strikes against a pin z at the
noment when the sliding piece which is subjected to the pressure of a spring d
as left the slot of the part b, whereby the sleeve or bush A is arrested and the

page_text: screw B enters into action again. The pin z is carried on a ring or fixed to the
frame of the machine.
The nut or ring b is adjusted on the screw B so that it bears against the
collar a, at the descent of the screw B, at a moment when the tool is close to
or say about 1 millimeter away from the work piece, thus engaging the sleeve
or bush A. of low pitch.
According to this construction the tool is first moved very quickly against the
piece to be worked and before the tool touches the latter, the slower transmission
device is brought into action so that during the smaller travel a larger power
than before is produced.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is:
1st. In machine tools such as screw presses and the like, the arrangement
of a screw engaging with a bush having an outer screw thread of lower pitch,
and adapted to be quickly coupled and uncoupled by suitable devices; such
coupling and uncoupling taking place, if effected during the operation of the
machine, at the moment in which the tool touches, or leaves respectively, the
piece to be worked, in order to obtain for the actual work an increase of power.
2nd. A mode of construction of the invention claimed in Claim 1 in which
a piece, sliding in a slot of the coupling device effects the disengagement of
a bush A, by a pin y, provided on such piece x, striking an adjustable pin z, at
the rise of the screw or tool; and during the descent of the screw and tool, couples
a ring b of the screw B with a collar a of the bush A.
Dated this 10th day of November 1898.
FELLS & JAMES,
Agents for the Applicant.