Safety Device for Electrical Elevators or Cranes.
Year: 1894

page_text: Date of Application, 12th Sept.. 1.94
*Complete Specification Left, 29th Apr. 1895-Accepted, 5th June, 1895
PROVISIONAL SPECIFICATION.
A Safety Device for Electrical Elevators or Cranes.
1, BENJAMIN WILLCOX of 47 Lincoln's Inn Fields in the County of
London Patent Agent do hereby declare the nature of this invention (which has
been communicated to me from abroad by Eisenwerk vormals Nagel and Kaemp
Actien Gesellschaft of Uhlenhorst, Hamburg in the Empire of Germany) to be
as follows:-
In hydraulic elevators or cranes the maximum limits of power are determined
by the sectional area of the plunger and the amount of hydraulic power available
and in steam elevators or cranes, the maximum limit of their working capacity is
determined by the diameter of the piston and the existing steain pressure, but
electro motors, may, occasionally be strained so far even as to produce about three
or four times more than their normal work. In the case of electrical elevators or
cranes therefore, there is always the danger of that if they should be employed
for raising unduly heavy loads, or if the load should catch against, say, the
hatchway edge of a ship, the frame-work is liable to be deformed, and the whole
elevator or crane to be put out of working order.
It is the object of this invention to provide an arrangement obviating such
accidents the said arrangement consisting of a roller or pulley or the like, mounted
upon one arm of a lever, over which roller pulley or the like the load supporting
chain or rope is passed, while the other arm of the lever is weighted by means of a
counter-weight or its equivalent, a spring, in such a manner that normal loads are
not capable of drawing down the arm of the lever carrying the roller pulley or
the like and raising the weight. When, however, the allowed inaximum load is
exceeded, the pressure of the weight or spring is overcome, whereby the lever is
caused to turn on its centre and in its movement it actuates an instantaneous switch,
so that the current is interrupted and the elevator or crane ceases to be operated
and it is therefore impossible to lift a load, exceeding the allowed maximum weight,
and the elevator or crane is therefore not liable to damage if the load, it is
employed to raise, happen to catch or to be jammed.
Dated the 12th day of September 1894.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, W.C., Agents.
COMPLETE SPECIFICATION.
A Safety Device for Electrical Elevators or Cranes.
I, BENJAMIN WILLCOX, 47, Lincoln's Inn Fields in London do hereby
5 declare the nature of this invention (a communication to me from abroad by
The Eisenwerk vormals Nagel & Kaemp Actien Gessellschaft of Uhlenhorst,
Hamburg, in the Empire of Germany) and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
;
In hydraulic elevators or cranes the maximum limits of power are determined

page_text: by the sectional area of the plunger and the amount of hydraulic power available
and in steam elevators or cranes, the maximum limit of their working capacity is
determined by the diameter of the piston and the existing steam pressure, but
electro motors may, occasionally, be strained so far even as to produce about
three or four times more than their normal work. In the case of electrical
elevators or cranes therefore there is always the danger that if they should be
employed for raising unduly heavy loads, or if the load should catch against, say,
the hatchway edge of a ship the framework is liable to be deformed, and the
whole elevator or crane to be put out of working order.
It is the object of this invention to provide an arrangement obviating such
accidents.
On the annexed drawing
Figure 1 is a side view of the arrangement.
Figure 2 is likewise a side view of same showing a spring in lieu of a counter-
weight.
The arrangement consists of a roller or pulley A or the like mounted upon one
arm of a lever B, over which roller, pulley or the like the load supporting chain
or rope C is passed, while the other arm of the lever is weighted by means of a
counter weight D (Fig. 1) or its equivalent a spring E (Fig. 2) in such a manner
that normal loads are not capable of drawing down the arm of the lever carrying
the roller, pulley or the like and raising the weight. When however the allowed
maximum load is exceeded, the pressure of the weight or spring is overcome,
whereby the lever is caused to turn on its centre and in its movement it actuates
an instantaneous electric switch F, G so that the current is interrupted and the
elevator or crane ceases to be operated, and it is therefore impossible to lift a load,
exceeding the allowed maximum of weight and the elevator or crane is therefore
not liable to damage if the load, it is employed to raise, happen to catch or to. be
jammed.
Having now particularly described the nature of said invention and in what
manner the same is to be performed, I declare that what I claim is :-
In an electrical elevator or crane the combination of a lever, carrying upon its
shorter arm a roller or pulley over which the load supporting chain or rope is
passed whilst the longer arm is weighted by means of a counter weight or a spring,
with an instantaneous switch connected there with essentially as and for the purpose
described and shown.
Dated this 29th day of April 1895.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C.,. Agents.