An Improved Arrangement for Varying the Length of Stroke of Reciprocating Parts of Machines.
Year: 1895

page_text: Date of Application, 10th June, 1895-Accepted, 13th July, 1895
COMPLETE SPECIFICATION.
An Improved Arrangement for Varying the Length of Stroke of
Reciprocating Parts of Machines.
We, BERNDT AUGUST HJORTH and FILIP HENRIK GETZMANN, both of
No. 5 Klara Norra Kyrkogata, Stockholm, in the Kingdom of Sweden, Merchants,
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 :-
This invention relates to an arrangement by means of which the length of stroke.
of the reciprocating parts of a machine may be varied in an easy and convenient
manner.
The invention is illustrated in the accompanying drawing in which
Figure 1 is a longitudinal section of the improved device and
Figure 2 is a vertical cross section on the line x-x of Figure 1.
The arrangement consists of a driving-shaft a, which is movable lengthwise and
provided at one end with a crank-pin located obliquely in such a manner that its
geometrical axis will describe a conical surface as the driving-shaft revolves. The
crank-pin may be attached either eccentrically to the end of the driving-shaft a so
as to converge to the axis of the latter-as shewn in the drawing-or it may be
attached to the central portion of the end of the driving-shaft, diverging from its
axis. On the crank-pin b a spherical bearing c is arranged in which the crank-pin
can be shifted longitudinally, said spherical bearing or box forming at the same
time a gudgeon which fits into a correspondingly shaped socket in the end of the-
connecting-rod d. This rod is guided laterally by the driving-shaft bearing, into
which it enters through a recess e, so that the connecting-rod with its ball-bearing
cannot be shifted in the direction of the axis of the driving-shaft. The outer end
of the crank-pin b may, of course, be free, but for the sake of rigidity it is advisable.
to attach it to the end of a journalled pin g, whose axis forms a prolongation of
that of the driving-shaft a.
When the driving-shaft is shifted longitudinally, the crank-pin will cause the
ball-gudgeon c, which cannot move in the same direction as the shaft, to move from
or approach to the axis of the driving-shaft, and consequently, as the latter rotates,.
the centre of the connecting-rod end will describe circles of greater or less diameter
according to the position of the ball on the crank-pin, or in other words the stroke
of the connecting-rod will vary. By the arrangement described above very slight
alterations in the length of the stroke can be made, since the variation in the latter
depends directly on the motion of the driving-shaft axially and this motion may be
made very small.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
An improved arrangement for varying the length of the stroke of reciprocating
parts of machinery, consisting of a driving-shaft a movable lengthwise and provided
at one end with a crank-pin b, which converges to or diverges from the axis of said
driving-shaft and which can be shifted longitudinally in a surrounding spherical
box c, forming a gudgeon fitting into a socket in the end of a connecting-rod of the
reciprocating part of the machine, said connecting-red being prevented from
participating in the motion lengthwise of the driving-shaft, all with a view to.

page_text: causing the spherical box or gudgeon during the rotation of the driving-shaft to
describe circular paths of greater or less diameter and consequently increase or
decrease the length of stroke of the connecting-rod, according to the length of the
way in which the driving-shaft with its crank-pin is shifted.
Dated this 10th day of June 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicants.