Improvements in or applicable to Electrically Driven Cranes.
Year: 1897

page_text: Date of Application, 30th Apr., 1897-Accepted, 19th June, 1897
Improvements in or applicable to Electrically Driven Cranes.
I WILLIAM CRAVEN of the Vauxhall Ironworks, Osborne Street, Manchester,
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 :-
My said invention relates to improvements in the means for controlling the
lifting lowering and brake appliances of cranes and consists in the special adaptation
of the coil brake device, described in the Specification of my previous Patent
No. 21883 of A.D. 1891 and of its combination with the means for controlling the
lifting and lowering motions of an electrically driven crane.
In order that my invention may be more clearly understood I will describe the
same with reference to the accompanying drawing in which
Fig. 1 is an elevation of a travelling crane with my said invention applied
thereto and
Fig. 2 is a sectional elevation of a detail through -x of Fig. 1.
A is the lifting barrel, B is the brake drum gearing with the lifting barrel or
connected therewith by suitable gearing, C is a flexible hand brake secured at one
end coiled several times round the brake drum and provided with a freely sliding
weight D at its free end and operating in the manner described in my said previous
patent according as the weight acts or does not act on the coil.
The position of the weight is controlled by a cam bar E as described in my said
previous specification.
The sliding of the cam bar E is effected by a lever E¹ having its fulcrum in the
side shaft F which is preferably square and takes in a corresponding square
aperture in the lever E. In lieu of a shaft of prismatic form a round shaft with
a flat thereon, or a round shaft with a groove and a corresponding sliding key or
feather may be used. The object of such a side shaft with a sliding attachment
of the lever E' is to enable the brake to be operated from a fixed position on
the crane notwithstanding the varying position of the winding barrel on the cross
girders.
The side shaft F is connected by a link F2 and levers F3 F' to the lever G¹
which operates the commutator of an electric switch G which directs the current
to the electro motor H. The latter drives the lifting barrel A forwards or
backwards according to the direction in which the spindle of the electro motor is
caused to turn by the position of the switch handle.
The switch is of the reversing type with a neutral point on the commutator at
which no current is transmitted to the electro motor.
The angles of the levers connecting the cam bar E with the switch handle or
alternately with a foot lever H (for the same purpose) are so arranged as that when
the commutator is at the said neutral point the depression in the cam bar E is in
its central position when the brake will be operative. On moving the commutator
forwards or backwards the cam bar E will simultaneously slide forwards or
backwards and thus take off the brake as the electro motor comes into action for
the purpose of lifting or lowering the load.
By such a combination of parts the load is always under control either of the
brake or of the electric current.

page_text: 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. In an electrically driven crane the combination of a coil brake a cam bar
connected with and operated by the reversing mechanism of an electric switch in
such a manner that when an electric current is directed to the driving motor of a
crane the brake is taken off but that while no current is passing the brake is
operative substantially as set forth and described.
2. In an electrically driven crane a coil brake a cam bar operated by and
mounted so as to slide on a side shaft levers and connections as shown and a
commutator or electrical switch the whole combined and arranged so that the
brake is rendered inoperative simultaneously with the reversal of the current
substantially as set forth and described.
Dated this 29th dar of Anxil 1907
E. T. WHITELOW, A.M. Inst. C.E.,
70 Deansgate, Manchester, Agent for the Applicant.