Improvements in Lifting-jacks.
Year: 1894

page_text: I, EDWIN
Improvements in Lifting-jacks.
RUTHVIN STILWELL, of 513 1st Street, Dayton, County of
Montgomery, State of Ohio, United States of America, Engineer, 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:
This invention relates to improvements in lifting-jacks.
The object of said improvements is to provide a lifting-jack, which, besides
being capable of performing, generally, the work required of a machine of this
character is especially designed for and adapted to railroad work. It is well
known by those familiar with railroad repairing that sometimes, while repairs are
being made it is important that the load held by the jack be quickly let down and
the jack speedily removed to avoid impending danger. To accomplish this I
provide mechanism through the agency of which the lifting bar may be instantly
lowered; and further I provide mechanism for lowering said lifting bar step by step
when the character of the work requires a gradual letting down, and also
mechanism to sustain the operating lever and lifting bar with its load, at one half
notch.
The various parts of the jack as hereinafter described are constructed of steel
and malleable iron.
In the drawings hereto annexed and forming a supplement to the Specification,
Figure 1 represents a vertical section of my improved lifting-jack;
Fig. 2, detail side and front elevations of the vibrating plate;
Fig. 3, detail side and front elevations of the bell-crank lever;
Fig. 4 is a detail side and Fig. 4A a front elevation of the retaining pawl;
Fig. 5, a side elevation of the lifting-jack;
Fig. 6, a plan view of the inner end of the operating lever;
Figs. 7 and 8 represent detail side and front elevations of the lifting pawl;
Figs. 9 and 10, detail side and front elevations of the half-way stop.
Coming to a specific reference, 1 indicates the supporting and enclosing frame
provided as usual with a central longitudinal opening, rectangular in cross section,
and extending throughout its entire length, and a vertical slot 2 in the rear; the
front of the frame adjacent to the operating mechanism, open from a point above
the retaining pawl to a point below the operating lever, as shown in Fig. 1.
3 indicates a notched lifting bar having a bearing block 4 and a base 5; this bar
moves in the central opening in the frame and the base portion 5 in the slot
therein in a well known manner.
6 indicates a transverse pivot pin journalled in bosses in the sides of the frame;
7 is a retaining pawl journalled on said pivot pin, and provided with a lug 8
projecting from one side thereof, and a gravity plate 9 cast integrally with the pawl

page_text: to give the upper end of said pawl sufficient weight to cause it to normally engage
with the notches on the lifting bar.
10 is a lug projecting laterally from the outer side of the plate 9 and through
an opening 11 in a side of the frame.
12 designates the lifting pawl having a gravity plate 13 at its upper end and a
lug 14 projecting laterally from the outer side of said plate and through an
opening 15 in the frame. This pawl, gravity plate and lug thereon are of a single
casting, and similar in construction to the parts on the retaining pawl.
16 is a casting forming the socket for the operating lever, having a fulcrum on
a shaft 17 journalled in bosses on the sides of the frame.
18 is a flange projecting from the lower side of said socket casting to impinge
with the lower front of the frame to stop and maintain the operating lever in a
horizontal position.
22 indicates a pivot pin journalled in bosses in the sides of the frame, and 23 is
a stop mounted on said pin with its lower end projecting through a slot in the
lower front of the frame in which slot it may oscillate; on the upper end of this
stop there is a projection or flange 24 of a two-fold thickness, the function of which
is to limit the upward movement of the operating lever to a half throw, and
therewith the downward movement of the lifting pawl to a half notch on the lifting
bar, which relieves the retaining pawl of the load and transfers it to the lifting
pawl; to accomplish this the stop 23 is turned upon its axis by bringing the foot in
contact with the lower exposed portion of said stop, this throws the projection or
Hange on the upper end of said stop in the path of the projecting end or
extension 25 on the lever socket, and thereby the movement of the latter is
arrested at half way. When not maintained in this position by the weight of the
load, the stop drops by gravity to the position shown in Fig. 1, and the projection
or flange thereon abuts with the inner surface of the frame to hold the stop in said
position. To lower the lifting bar step by step, the lugs 10 and 14 that project
from the gravity plates of the pawls, and through the openings 11 and 15 in the
frame, are alternately pressed forward thereby releasing one at a time, said pawls
from the notches in the lifting bar.
full
Thus far I have described the mechanism for elevating the lifting bar by a
throw or a half throw of the operating lever, and the means for gradually lowering
said bar step by step. I will next describe certain trip mechanism through the
agency of which said lifting bar may be. quickly dropped from any point of
elevation.
26 denotes a vibrating plate mounted on the pivot pin 6 on one side of and
adjacent to the retaining pawl 7; this plate has a preponderance of weight at its
upper end to maintain it in proper position, and semi-circular recesses 27 and 28
in its periphery, in the former of which, the lug 8 on the retaining pawl lies.
30 is a bell-crank lever having a horizontal extension or flange 31 on the vertical
arm thereof to trip the lifting pawl; said lever has its fulcrum at a where its
journal 32 enters a boss in the side of the frame. This lever occupies space
between a side of the lifting bar, and the frame, in the rear of and on a line
with the plate 26 so that the end 33 of the horizontal arm projects into the
recess 28 in said plate. The plate 26 normally maintains the vertical arm of the
bell-crank lever on the incline as shown in Fig. 1; a position to prevent
the flange 31 from coming in contact with the notches on the lifting bar.
34 is a trip pawl pivoted to one side of the socket casting 16, and when not in
use, is turned backward upon its axis to the position shown in Fig. 1, in which
position, the lug 35 thereon engages with a similar lug 36 projecting from one of
the bearing bosses of the socket easting 16 and thereby maintains said pawl in
that position.
Briefly describing the operation of simultaneously tripping the retaining and
lifting pawls to instantaneously lower the lifting bar, the pawl 34 is turned upon
its axis to the position shown in dotted lines, Fig. 1, the operating lever is raised
which causes the pawl 34 to impinge with the lower end of the vibrating plate 26

page_text: causing the latter to press against the lug 8 on the retaining pawl, and against the
vertical arm of the bell-crank lever 30 which causes the flange 31 to come in
contact with the lifting pawl to move it out of the notches in the lifting bar,
and thus are the two pawls simultaneously tripped to instantaneously drop said
lifting bar.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1. A notched lifting bar in combination with an operating lever, a trip pawl,
and a lifting pawl pivotally mounted on said operating lever, a vibrating plate
actuated by said trip pawl; a retaining pawl, and a bell-crank lever actuated by
said vibrating plate, through the agency of which mechanism, the lifting bar may
be instantaneously lowered, as herein described.
2. A notched lifting bar in combination with au operating lever provided with
a projection 25, a lifting pawl pivoted to said operating lever, and a half-way
stop pivotally mounted below said operating lever, whereby the movement of
said lever may be limited to a half-way throw and the lifting bar moved a
distance less than one tooth, substantially as herein described.
3. In a lifting-juck, the combination with the frame, lifting bar and operating
lever, of lifting and retaining pawls pivotally mounted as described, a vibrating
plate mounted adjacent to the retaining pawl, a bell-crank lever pivoted adjacent
to said vibrating plate and lifting pawl, and a pawl pivoted to the lifting lever,
adapted to come in contact with said vibrating plate and thereby simultaneously
trip said retaining and lifting pawls to instantaneously drop the lifting bar.
4. The combination with the frame having openings 11 and 15 and the lifting
bar, of a retaining and a lifting pawl, provided respectively with gravity plates 9
and 13 and lugs 10 and 14 projecting therefrom and through the openings 11
and 15, the operating lever 16 provided with the extension 25, and the stop 23
pivoted below the operating lever and adapted to be turned upon its axis to
limit the throw of said operating lever.
°
5. The combination with the frame having openings 11 and 15 in oue side
thereof, the lifting bar, and the operating lever, of a lifting and a retaining
pawl the latter being provided with a lug 8 and both of said pawls being provided
respectively with lugs 10 and 14, the vibrating plate 26 adjacent to the retaining
pawl, the bell-crank lever 30 with flange 31, and pivoted adjacent to .said
vibrating plate and lifting pawl, the operating lever and means thereon for moving
the plate 26.
Thin oath dow of October 1901
ALLISON BROS.,
Agents for the Applicant.