IMPROVEMENTS IN CRANES AND HOISTING MACHINERY, AND IN SAFETY APPARATUS TO BE APPLIED THERETO
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by James Taylor at the Office
of the Commissioners of Patents, with his Petition, on the 19th
October 1874.
I, JAMES TAYLOR, of Birkenhead, in the County of Chester, Engineer,
do hereby declaro the nature of the said Invention for “IMPROVEMENTS IN
CRANES AND HOISTING MACHINERY, AND IN SAFETY APPARATUS TO BE APPLIED
THERETO," to be as follows:-
In powerful steam cranes and such like hoisting apparatus, to avoid
the risks of overstraining and damage which may arise from negligence
on the part of the engineer or driver, or from the imperfect slinging or
guiding of the suspended load, I propose hereby to provide a means by
which not only the actual weight of the load lifted, but also the
maximum strain to which the crane and hoisting apparatus is subjected
from time to time may be weighed or measured instantaneously and
immediately under the observation of the engine driver or the person in
charge of the hoisting gear, who may also read off from the register and
record every-such weight or strain. By means of the same apparatus or
gear, and a suitable stop piece or stud, the engine may be reversed or the
steam shut off when a given strain on the apparatus is exceeded.

page_text: At the jib end of a crane, and preferentially to the suspending fork,
sling, or frame carrying the free hanging pulley, over which passes
the double end of the chain fall, or to a carriage or frame in which the
chain pulley or pullies are mounted or carried at the jib end, I connect
the shorter end of a lever arm carried on or by a fulcrum stud mounted
or fixed upon the jib itself (or in any other convenient manner); to the
longer end of this lever arm may, in turn, be connected the shorter end
of another lever arm (or levers) interposed between it and the upper end
of a tension bar or connecting rod, by which the strain applied to or the
load lifted by the crane is transmitted (correspondingly reduced in
amount) down to a tell-tale or indicating (or indicating and recording)
instrument which I propose to fit, mount, or apply upon or by the side
of the platform where the driver stands. The lower end of this tension
bar or connecting rod from the jib end may be connected directly to and
with the indicating instrument or apparatus by means of a link, sling,
or lever.
The indicating instrument may be a freely suspended and weighted
arm or lever moving in the arc of a circle upon or against a graduated
and divided scale, upon which a sliding indicating piece is moved or slid,
and it remains at rest at the end of the movement, so that the maximum
strain may be read off and recorded; the sliding piece may be subdivided
and form a vernier scale for reading off the smaller or intermediate
weights or strains.
Instead of a weighted lever arm a steelyard arrangement, spiral
spring, or Salter's balance may be employed, the sliding indicator, index
hand, or pointer being added, or a self-acting cylindrical or other form
of indicator instrument may record with a pencil upon ruled paper the
maximum load or strain.
In connection with the tension bar or rod at the lower end thereof,
and separately from or connected with the indicating and recording
apparatus, a fixed or ajustable stop piece may be fitted, and so arranged
as to relieve a detent and discharge or weighted lever handle of the shut
off steam valve, or be arranged so as to operate upon the reversing gear
of the engine.