Improvements in Crank Mechanism.
Year: 1899

page_text: Date of Application, 25th Feb., 1899-Accepted, 23rd Sept., 1899
COMPLETE SPECIFICATION.
Improvements in Crank Mechanism.
We, WALTER HAY and EMERSON M. HOTCHKISS, corner Wooster and Wallace
Streets, of Newhaven, in the County of New Haven and State of Connecticut,
United States of America, Manufacturers, do hereby declare that the nature,
of this invention and in what manner the same is to be performed, to be parti-
cularly described and ascertained in and by the following statement:-
This invention relates to improvements in engine construction, more parti-
cularly adapted for motors, pumps, compressors and so forth, which comprise
tandem coupled cylinders and a crank shaft arranged in operative connection
with the reciprocating pistons of said cylinders; and the object of this improve-:
ment is to relieve such pistons of the thrusts or strains, which herebefore have
been experienced in the operation thereof.
This object is obtained substantially in the manner and by the means as illu-.
strated in the accompanying drawings, in which :-
Figure 1, represents a part sectional and part exterior view of a pair of single-
acting tandem arranged, yoke and crank operating or operated cylinders, pro-
vided with the improvements above referred to.
Figure 2, is a partial plan view of same.
Figure 3, is a cross sectional view of same on line ar, see Figure 1.
Figure 4 represents a part sectional and part exterior view of another pair of
tandem arranged, yoke, connecting rod and crank operating or operated cylinders,
improved in like manner.
Figure 5, illustrates a part plan view and part sectional view of same.
Figure 6, is a cross sectional view on line y y, see Figure 4.
Like letters of reference denote like parts in the drawings and specification.
The essential features of this invention consist in the application of integral,
differential rollers in connection with elementary engine construction of such
or similar type as shown in the accompanying drawings.
In the construction illustrated in Figures 1, 2, and 3, A, A, represent partial
views of the working cylinders, between which is placed the crank shaft B.
The yoke C, is adopted for operative connection with the pistons D, of said
cylinders with and by the intervention of the crank pin E, of said shaft. The
rods F, F, of the pistons are hinged to said yoke as seen at a a, while the pin E,
is embraced by blocks bb, which move within said yoke, see Figure 1.
Parallel to or with the center line of the cylinders extend the guides
each side of the yoke; at c said guides are shown united, simply to render the
structure more rigid, see Figures 1, and 3.
cc from
Adjustably attached to each side of the cylinders near the ends thereof, is
shown a yieldingly supported bifurcated bracket G, between which and the above
mentioned guides is placed a roller H, which consists of the major member d
and the minor member e.
The brackets are adjusted in relation to the yoke guides to maintain the major
:

page_text: member d of the rollers in contact with the guides and the minor members e in
contact with the inner faces f of the brackets.
Under such conditions the rollers will move in unison with the yoke guides,
but the ratio of the linear travel of the rollers to that of the yoke is indentical
with the difference in circumference between the major rollers and the- minor
ones.
If thus, for instance, the stroke of the yoke equals the circumference of the
roller part d then the rollers proper will move within a distance equal to the
circumference of the minor rollers e e.
Only a limited movement of the rollers is required to answer the purpose of
subdueing friction to a minimum.
The conversion of reciprocating motion of the piston into rotary motion of the
crank shaft causes more or less severe angular thrusts upon the yoke guide
bearings; but with this improvement where the bearings consist of compound
rollers, there is no friction requiring lubrication, also strains upon the pistons
can not exist, since same are borne by the rollers.
In providing a hinged or loose connection for the piston rods near the center
of the yoke, it is obvious that a possible displacement of the yoke itself can have
but little or no detrimental effect upon the pistons.
Yokes guided between or upon compound rollers arranged substantially as
shown, avoiding strains and requiring no lubrication, constitute an essential
feature in engine constructions for motor carriages and so forth.
In the construction illustrated in Figures 4, 5, and 6, the rods I, are employed
for connection of the shaft E', with the outer ends g of the yoke C.
The roller retaining brackets are embodied in continuous bars G¹, reaching
from one cylinder end to the other, and the piston rods F have_a_pivotted_or
hinged connection with the yoke substantially as shown at a¹ Figs. 4 and 5.
It is evident that compound rollers are useful in converting reciprocating
motion into rotary motion as well as in converting rotary motion into recipro-
cating motion, and such means may be applied in many similar kinds of engine.
construction without departing from the nature of my invention.
Having now particularly described and ascertained the nature of our said in-
vention, and in what manner the same is to be performed, we declare that what
we claim is :-
1. In engine constructions, the combination with tandem arranged cylinders
and the pistons thereof of a yoke connecting with the rods of said pistons, a
crank shaft rotated by said yoke, guides extending from each side of said yoke,
adjustable and yieldingly supported brackets or bars retained normally in
parallel position to said guides, and integral, differential rollers establishing
rolling contact with and of said guides and brackets or bars, for the purpose as
set forth.
2. The combination with tandem arranged cylinders and the pistons thereof,
of a piston rod connecting guide yoke, connecting rods and a crank shaft, adjust-
able and yieldingly supported parallel bars or brackets and differential rollers,
the large and small member of said rollers being respectively in contact with
said guide yoke and the said parallel bars, to relieve the pistons of undue strains,
substantially in the manner as shown and for the purpose set forth.
Dated this 28th day of Wabruary 1800
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.