A COMPOUND DRIVING LEVER OR CRANK
Year: 1879

page_text: LETTERS PATENT to Robert Craib Ross, of the Firm of Messieurs Ross and
Sons, of Manchester, in the County of Lancaster, Printers' Machinist, for the
Invention of "A COMPOUND DRIVING LEVER OR CRANK,"
PROVISIONAL SPECIFICATION left by the said Robert Craib Ross at the Office
of the Commissioners of Patents on the 30th July 1879.
"
ROBERT CRAIB Ross, of the Firm of Messieurs Ross and Sons, of Manchester, in
the County of Lancaster, Printers' Machinist. A COMPOUND DRIVING LEVER OR
CRANK."
My Invention is applicable to machines driven by hand, and consists of a lever
working on a stud fixed to the driving disc or wheel, and so arranged that the
distance between the centre of the driving disc and the crank handle may increase
in proportion to the work to be done. The end of the crank nearest the working,
centro is eccentric; the plane of the eccentric works against a balance lever attached
to a spring, the balance lever being so adjusted that the strain of the spring acting
upon the eccentric plane regulates the distance of the driving handle from the
working centre, according to the force required. At the back of the balance lever.
is a regulating stop screw, by which the handle can be adjusted to remain in any
given position. In some cases I place a stop stud in a hole in the disc. when it is.
desirable for the crank to be retained in any particular position.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Craib Ross in the Great Seal Patent Office on the 29th January
1880.
ROBERT CRAIB Ross, of the Firm of Messieurs Ross and Sons, of Manchester, in
the County of Lancaster, Printers' Machinist. "A COMPOUND DRIVING LEVER OR
CRANK."
My Invention of a compound driving lever or crank is applicable to machines
driven by hand or foot, and consists in the adaptation and application of a lever or
crank so arranged that whilst being driven the distance between the centre of the
shaft driven and the lever handle or mover may increase or diminish, according to
the strain applied to the lever or crank, or in proportion to the force required to
drive the machine or instrument to which it is applied, by which ineans a self-
adjusting lever power is obtained. And in order that my Invention may be-fully
understood I will proceed to describe the accompanying Sheet of Drawings, reference
being had to the figures and letters marked thereon. Fig.1 is a front elevation,
a is the disc
and Fig. 2 is a side view of my compound driving lever or crank.
fixed on the shaft or instrument to be driven. At a convenient distance from the
centre of the disc on the stud b the driving lever or crank c is mounted, so that it
may move as required. At one end of the lever or crank at d, d, is formed an
eccentric curved plane, upon which one end of the balance lever e is made to act.
The balance lever e is fitted on a stud f, and connected to the spring g'at g¹ by the
hasp m, and rests on the eccentric curved plane of the lever or crank at a¹. By
this means the elastic force of the spring g acts upon the eccentric curved plane of
the lever or crank at.d, d. The force of the spring thus acting upon the curved
plane on the lever or crank imparts a regulating power according to the strain put
upon the plane, which is made to rise or fall to or from the centre 8, as required,
the lever or crank being at liberty to move on the stud b. By this means the lever
or crank at the handle h will move to or from the centre of the disc or driven shaft 8,
_ thereby giving-more-or-less-driving-leverage as-the-distance from the centre is
increased or diminished. At the same time a self adjusting power is imparted to
the lever by means of the force put upon the handle at h, and the strength of the
spring acting upon the plane d, d. The elastic force of the spring is regulated by
compressing it more or less by the bolt and screw in connection with the hasp m,
by which the spring is attached to the balance-lever e. The length of the travel
of the lever or crank is adjusted by moving the stop bolt n to or from the balance
The screw is fixed in the
lever, or by a stop stud secured in one of the holes o.
disc, and acts as a friction pad to the action of the lever. An india rubber pad k
is used as a buffer stop to the lever. The driving lever may be fixed on a machine
without introducing a disc, as herein described, or it may be adjusted by other
means, but I prefer the disc and arrangement there described as being convenient
and least likely to get out of order. Having thus stated the nature of my Inven-
tion, and described a manner of performing the same, I wish it to be understood
that I do not limit myself to the details given, but what I claim is, increasing or
diminishing the distance of the handle, or mover from the centre of a compound
driving lever or crank by an action self adjusting according to the power required;
also the mechanism for effecting the same, substantially as shewn and described:
In witness whereof, I, the said Robert Craib Ross, have hereunto set my hand
and seal, this Twenty eighth day of January, One thousand eight hundred