Improvements in Crank and Slotted Crosshead Mechanism.
Year: 1891

page_text: Date of Application, 2nd June, 1891-Accepted, 18th July, 1891
COMPLETE SPECIFICATION.
[Communicated from abroad by THE LAFORGE ENGINE COMPANY, doing
business in Jersey City, County of Hudson, New Jersey, United States
of America.]
Improvements in Crank and Slotted Crosshead Mechanism.
1, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings in the County of Middlesex, 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 :---
In the accompanying drawings forming part of this Specification and in which
Figure 1 represents a sectional side view of the yoke and crank block showing a
portion of the two piston-rods.
Figure 2 face view of one of the guides of the yoke showing the block in the
groove.
This invention relates to an improvement in that class of steam-engines in which
a pair of cylinders are arranged in line with each other, the two pistons connected
between the cylinders by a yoke forming a guide in which a crank-block operates,
so that a reciprocating movement imparted to the pistons, will through the said
block, convert said reciprocating movement of the pistons into a rotary movement
of the crank, and is an improvement upon the steam engine for which British
Letters Patent No. 2948 of 1889, dated February 19th 1889 were granted.
In that invention the guide which carries the crank block is in the form of
two parallel bars, arranged at right angles to the direction of reciprocation of
the pistons, and between which guides the crank-block slides under the rotary
movement of the crank, and so that the reciprocating movement of the pistons
operating through said yoke, will convert the reciprocating movement of the
pistons into the rotary movement of the crank. The pistons also receive an
oscillatory movement, whereby the pistons themselves operate as the valves for
the admission and exhaust of steam. This oscillatory movement is imparted by
means of a cam-shaped slot in the face of the guides or yoke in which a stud
on the crank-block works, and so that as the crank-block reciprocates from one
end of the guides to the 'otlier, the said pin operating in the crank-slot, imparts
the requisite rocking or oscillatory movement to the yoke and consequently to
the pistons. The engine is designed to run with great rapidity, and wear to
some extent between the cam-grooves and the stud working therein is unavoid-
able; such wear permits a corresponding play between the stud and sides of
the groove, which play will produce a rattling in the working of the engine.
The object of the present invention is to overcome this difficulty and make the
engine, so far as the oscillatory movement of the yoke is concerned, noiseless, and
the invention consists in the arrangement of an elastic block around the stud in the
said cam-grooves, which block is adapted to expand to take up any wear or looseness
which may occur between the sides of the grooves, and the stud.
In illustrating the invention only so much of the engine is represented as is
necessary to a clear understanding.
A, represents one piston and B the other, it being understood that they are
arranged in substantially axial line with each other. The connection between
the two pistons is formed by the yoke, composed of one guide C, attached to
the piston A, and a corresponding D, attached to the piston B, the two guides
being parallel, and the plane of their faces being at right angles to the path of
reciprocation; they are connected at their two ends by studs E, so as to hold
them in their proper relation to each other. Between the two guides CD, the
crank-block F, is arranged, and in which block, the crank-pin G works; and so"

page_text: that as the yoke reciprocates under the operation of the piston, the crank will
be caused to revolve, the crank-block sliding between the two guides. In the
face of the guides is a cam-shaped groove H, see Fig. 2, into which a stud I
projects from the crank-block, this stud traversing the groove as the block
moves between the guides, the crank-block and stud always following a straight
line because of being held in a corresponding plane by the crank-pin, will
impart an oscillating movement to the yoke corresponding to the said cam-
shaped groove.
To give a considerable extent of bearing between the stud and the side of
the groove, the stud is of less diameter than the width of the groove, and a
block is introduced upon the stud, the said block being of a width corre-
sponding to the width of the groove, and so that while the stud will rotate
freely in the block, the block will slide in the groove. Instead of making this
block solid, or making the stud of a diameter to take a bearing upon both
sides of the groove, the block is constructed in two parts ab; in the face of
one block, as b, a seat is made for the stud I, and upon the other block as a,
a spring dis arranged, curved so as to form a scat for the opposite side of the
stud I, as shown, this spring having a tendency to force the one part a of the
block from the other part by its bearing upon the stud I and consequently
holds the parts a basunder with a yielding force, the power of the spring being
sufficient to press the two parts against their respective sides of the groove H,
and yet bear firmly upon the stud I, consequently any wear which may occur
between the stud and the block, or between the block and the sides of the
groove, will be taken up by the spring d, and the parts thus held firmly against
the stud and against the corresponding sides of the groove, prevent any possible
play or rattle in the groove, yet perfect freedom is permitted in the operation
of the block upon the stud to impart the oscillating movement to the yoke.
While specially adapted for the engine of the before mentioned Patent, the
invention is applicable to other engines in which oscillatory movement of the piston
is required.
The invention is also applicable to other machines in which a like reciprocating
block is arranged to work in a groove or slot for the purpose of converting
reciprocating into rotative motion or vice versa, the invention is therefore not to be
understood as specifically limited to use in a steam engine.
No claim is made in this application to the construction of the crank-block or to
the yielding character of the yoke also illustrated in the drawing, these features
constituting the subject of an independent application filed in
herewith.
even date
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondents I declare that what I claim is
First. In a steam-engine substantially such as described, and in which the pistons
have a reciprocating movement imparted to them and also an oscillatory movement,
a yoke attached to the pistons and so as to reciprocate therewith, the plane of the
yoke being at right angles to the plane of reciprocation, combined with a crank-pin
block arranged to slide in said yoke in a plane at right angles to said path of
reciprocation, the face of the said yoke constructed with a cam-shaped groove and
the crank block provided with a stud adapted to work in the said groove, a block
in said groove and around said stud, the said block consisting of two parts, the one
part constructed with a seat upon one side of said stud, and the other part with an
elastic seat upon the opposite side of said stud, the said two parts adapted to
yieldingly bear against the respective sides of said groove under the force of the
said elastic seat upon the said stud, substantially as described.
Second. In a yoke constructed with a cam-shaped slot or groove and having a
stud arranged to reciprocate in said groove, whereby the reciprocating movement
of one part is converted into rotative movement of the other part, or vice-versa, the

page_text: combination therewith of a block in said groove, and around said stud, the said
block consisting of two parts the one part constructed with a seat upon one side of
said stud and the other part with an elastic seat upon the other side of said stud, -
the said two parts adapted to yieldingly bear against the respective sides of said
groove under the force of the said elastic seat upon the said stud, substantially as.
described.
Dated this 2nd day of June 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.