IMPROVED MECHANISM FOR CONVERTING RECIPROCATING INTO ROTARY MOTION
Year: 1882

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in
the County of Middlesex, Patent Agent, for an Invention of "IMPROVED
MECHANISM FOR CONVERTING RECIPROCATING INTO ROTARY MOTION."
A communication from abroad by Frank Elbing, of Algersdorf, Bohemia, in
the Empire of Austria.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 24th January 1882.
ALEXANDER MELVILLE CLARK of 53 Chancery Lane in the County of
Middlesex, Patent Agent. "IMPROVED MECHANISM FOR CONVERTING RECIPRO-
CATING INTO ROTARY MOTION." [A communication from abroad by Frank
Elbing, of Algersdorf, Bohemia, in the Empire of Austria.]
This Invention relates to mechanism for converting reciprocating rectilinear to
continuous rotary motion, and has for its object to overcome the dead centres of
the usual crank mechanism without loss of motion and power. The Invention
consists in a shifting crank pin guided to move in a path eccentric to the crank
axis as hereinafter described.
According to one arrangement the crank arm has a curved slot forming an are
of which the radius of the crank arm is the chord. The crank pin passes through
this slot and is free to move therein to the extent of the slot, and is carried by a
radius lever or arm pivoted to the crank arm at a point coincident with the
centre form which the curved slot is struck. Immediately behind the crank arm
there is a stationary guide slot of circular form eccentric to the crank shaft into
which a projection of the crank pin enters. The connecting rod having recipro-
cating motion is connected to the crank pin and the latter being obliged to move
in the eccentric circular path of the guide slot and being at same time engaged in
the slot of the crank arm, carries the crank arm round. In no position of the
parts can the crank pin, the centre on which the radius arm carrying the crank pin
pivots and the crank shaft or axis, come into line and there are consequently no
dead centres at the ends of the stroke.
According to a modified arrangement, a disc or wheel is substituted for the
eccentric guide slot. A crank disc is pivoted by an axial pin to said wheel at a
suitable radius and is connected by a pin to the end of the crank arm, and is
provided with an eccentric which forms the crank pin to which the connecting
rod is attached. The crank pin is of large size comparatively so that the
movement of the crank disc or its axis is limited.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Melville Clark in the Great Seal Patent Office on
the 24th July 1882.
ALEXANDER MELVILLE CLARK of 53 Chancery Lane, in the County of
Middlesex Patent Agent. "IMPROVED MECHANISM FOR CONVERTING RECIPRO-
CATING INTO ROTARY MOTION." A communication from abroad by Frank
Elbing, of Algersdorf, Bohemia, in the Empire of Austria.
This Invention relates to mechanism for converting reciprocating rectilinear
to continuous rotary motion, and has for its object to overcome the dead-centres
of the usual crank mechanism without loss of motion and power.
The Invention consists in a shifting crank-pin guided to move in a path eccentric
to the crank-axis, as hereinafter described.
The Invention is illustrated in the accompanying Drawings, in which similar
letters of reference indicate corresponding parts in all the figures.
Figure 1 is a side view, and Figure 2 a sectional plan view, of crank mechanism
embodying the Invention. Figure 3 is a side view, and Figures 4 and 5 are
sectional plan views of a modification.
Referring to Figures 1 and 2, A is a crank-arm on an axis a. Bis the crank-pin,
fixed on an arm, b, that is pivoted to arm A by a pin, c, on which the crank-pin
and its arm b are free to turn. The crank-arm A is formed with a slot, d, that
is an are having its centre at pin c, and the crank-pin B has a projection, f, at the
back of its arm b, extending through the slot d. O is a plate fixed at the side of
the crank-arm, and formed with a guide-slot, e, eccentric to the main axis a, into
which alot the projection f of the crank-pin enters. The pitman or rod having
reciprocating motion being connected to pin B, the pin is moved in guide-slot c,
and by its engagement with the slot in arm A carries the arm around the axis a.
In no position of the parts can the pin B, axis c, and axis a, come into line, and
there are consequently no-dead-centres.at. the extremes of the reciprocations.
In the modified form shown in Figures 3, 4, and 5 a disk or wheel, g, is substituted
for the eccentric guide-slot. A is the crank-arm on an axis a. h is a crank-disk
pivoted to wheel g by an axial pin, i, and connected by a pin, k, to the crank-arm A,
and provided with a crank-pin, l, for the pitman m. The operation is the same in
principle. The crank-disk h, which is the equivalent of a crank-arm is guided
arbitrarily by the wheel g, and carries the main crank-arm A.
In Figures 4 and 5 the parts are shown at the extremes of movement. The
crank-pin is of large size, comparatively, so that the movement of disk h on its
axis is limited.
Having described the nature of the said Invention and the manner of performing
the same I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is.
1st. The crank mechanism consisting of slotted crank-arm A, crank-pin B,
hung by arm b on the crank-arm, and the grooved plate C, having a guide-slot
engaged by the crank-pin, substantially as shown and described.
2nd. The combination, with a crank, of a secondary crank engaging the main
arm and held in position by an eccentric guide, substantially as herein shown and
described.
In witness whereof I the said Alexander Melville Clark have hereunto set my
hand and seal this Twenty-fourth day of July AD 1989