Improvements in Levers and Linkages.
Year: 1890

page_text: Date of Application, 22nd May, 1890-Accepted, 28th June, 1890
COMPLETE SPECIFICATION.
Improvements in Levers and Linkages.
I, JAMES PLAISTER HARRISS GASTRELL, domiciled in Nassau, Germany and resident
therein at No. 2 Theodoren Strasse, Wiesbaden, but temporarily residing in Chicago,
Illinois, United States North of America, Gentleman, 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 :-
The object of my invention is to construct an improved mechanical device in which
the extremities of a lever or arm swinging on a centre, will describe a straight line,
and not a curve. My invention is especially applicable to scale beams, pumps, cranes,
looms, piano-key mechanism, treadles and other devices, in which a straight line action
of pull is desirable or essential.
In the accompanying drawings:-
Fig. 1 is a side view, showing my invention as applied to scale beams or other
walking beams;
Fig. 2 is a plan view of Fig. 1.
Fig. 3 is a plan view of a modification of Fig. 2.
Fig. 4 is a modified form of Fig. 1.
Fig. 5 is a plan view of Fig. 4.
Fig. 6 is another modification, showing the application of the movement to a
pump.
Fig. 7 is a plan view of Fig. 6.
Fig. 8 is a side view, shewing the application of my improved movement, by which
two movements are produced in a straight line, one at right angles to the other.
Fig. 9 is a modified form of the device shewn in Fig. 8, the angles in this case
being changed.
Fig. 10 is a side view, shewing the mechanism so constructed that two horizontal
movements in opposite directions are produced by a single vertical movement;
and
Fig. 11 is a view of a single set of links on one arm of a lever.
Referring to Figs. 1 and 2 in the first instance, I have shewn a lever having two
equal arms pivotted at F to a base of any suitable construction; these two arms
terminate respectively at E' and E³.
L' and L are the pivots on the base, to which are connected the long links
described hereafter.
Pivotted to the arms of the lever at E¹, are two links E' A and C E¹; these links
are pivotted at A and C respectively to links A B and B C, which are pivotted
together at the point B. A long link A L' is pivotted at L' to the base and to the
links above described at A, and a long link CL is pivotted at L' and to the links
at C. This series of links forms one half of the lever, and if the point B was moved,
it would describe a straight line, as shewn by dotted lines in Fig. 1.
The opposite arm of the lever is pivotted at E' to the links H E and E, D, which
in turn are pivotted to the links G H and D G at the points H and D; the latter
links are pivotted together at the point G.
The long link His pivotted to the links above described at H, and to the base
at L, while the long link D L is connected to the base at L' and to the links
at D.
These two sets of links being pivotted respectively at L' and L to the base, and
pivotted to a lever having its centre or fulcrum at F, as soon as one set of the links
move, the opposite set will move in the reverse direction, but the point G will travel
in a line parallel with that which the point B describes.

page_text: In Fig. 3 the arms of the lever are in line, and the base section is of a form to
accommodate this alignment. In some instances, only one set of links may be used,
as, for instance, when it is desirable to have the device operated upon, move in a
straight line, but it is immaterial whether or not the operating lever move in a circular
path, such, for instance, as shewn in Fig. 11.
The mechanism is especially applicable for use in balances and scales, pumps, key
lever mechanism for typewriting machines, walking beams of engines, valve gear,
treadles, gates, cork screws or nail removers, and many other devices in which it is
advantageous to have a straight line movement or movements, in which a lever must
necessarily form one of the leading elements.
In Figs. 4 and 5 I have represented the arms of the lever of different lengths, in
the present instance, two to one, the same idea being carried out in these figures as
in Fig. 1, with the exception that one arm of the lever is only one half the length of
the other arm, and the links appertaining thereto are reduced in proportion.
In Figs. 6 and 7, I have shown my invention applied to a hand pump, in which the
hand is reciprocated in a straight line, and the pump rod consequently moved in a
straight line, the two arms of the lever in this instance being side by side, and the
quadrangular link works are placed practically side by side, and the links composing
the cells are of different length, forming a lever of the second class; the two arms of
the lever may be amalgamated where circumstances permit, without departing from
my invention.
In Fig. 8 I have shewn my invention as applied to bell crank mechanism in which
a vertical straight movement is transformed into a horizontal straight movement, as
indicated by the arrow, the arms of the lever having its fulcrum at F being at right
angles to each other.
In Fig. 9 the same idea is carried out as in Fig. 8, with the difference that the arms
of the lever are at a different angle.
In Fig. 10, the devices shewn in Figs. 1 & 8 are combined, so that by moving the
point B downwards, as indicated by the arrow, the point G will be moved in a
direction indicated by its arrow, and the point N will be moved in a direction indicated
by its arrow, reverse to that of the point G. This mechanism is especially applicable
to the key mechanism of pianos, where a reverse motion is required, & where two
parallel motions are necessary, as in the above case.
It will be understood that the several links shown (as forming the quadrangular
link-work) may be of different lengths and proportions, depending on the construction
of the apparatus to which the invention is applied.
Having now particularly described & ascertained the nature of my said inven-
tion & what manner the same is to be performed, I declare that what I
claim is :-
1. The combination of the lever having its fulcrum at F, one arm of said lever
being pivotted to a quadrangular link-work, with long links pivotted to the link-
work as described & to a base pivot, substantially as set forth.
2. The combination of a two armed lever fulcrumed at F to the base, one arm
of said lever connected to a quadrangular link work, with long links connecting
said link work with a base pivot L', the other arm of the said lever being
pivotted to an independent set of quadrangular link work, said set being connected
to a base pivot L by long links, substantially as and for the purpose set forth
and in the manner described.
3. The combination of the lever fulcrummed at F, two arms of said lever being
at an angle to each other, with quadrangular link work pivotted to each arm,
with long links pivotted to the link work and to a base, substantially as
described.
4. The combination of the lever fulcrummed at F, the arms of which are at
an angle to each other, each arm pivotted to a quadrangular link work, one of
which is continued, forming a second quadrangular set of links pivotted, in turn,

page_text: to one arm of a second lever, the opposite arm of which carries a set of
quadrangular links, with long links connecting each set of quadrangular links
with the base, in substantially the manner described, whereby the movement is
reversed, substantially as set forth.
NEWTON & SON,
Agents for the Applicant.