MENTS IN SAFETY DETACHING HOOKS FOR MINING AND OTHER PURPOSES." IMPROVE
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by John Bray Craze at the Office of
the Commissioners of Patents on the 22nd March 1877.
JOHN BRAY CRAZE, of Wakefield, in the County of York, Engineer.
MENTS IN SAFETY DETACHING HOOKS FOR MINING AND OTHER PURPOSES."
IMPROVE-
My Invention relates to improvements in the mechanical construction and arrange-
ment of a self-acting swivel detaching hook suitable for mining and other purposes,
whereby increased safety and certainty of action is obtained.
In carrying out my said Invention I proceed as follows:-I make a suitable
metal box or case, wherein are formed any suitable number of laterally projecting
recesses placed opposite to each other. In each of such recesses I place a toothed
catch furnished with two externally projecting teeth conveniently placed on the
upper portion thereof, one below the other. The box or casing before mentioned
serves to enclose all the moving parts of the hook. The lower ends of such toothed
catches are carried upon suitable pins which pass through the cheeks of each of the
recesses before described.
In the ordinary working up and down of my improved detaching hook the
toothed catches are kept closed by a pair of suitable metal keys which are con-
veniently arranged within each recess on each side of the catch, such keys being
upheld by a suitable metal pin, which passing through the base of the catch thus
serves as a support to keep them in position.
Placed at the top of the hook is an iron swivel or shackle and bolt to which the
winding rope or chain is attached, and formed on the lower part of the spindle of
such swivel is a suitable flange.
On the inside of the upper portion of each of the catches before described is
formed a deeply notched recess, the upper projections of which take on to the flange
so formed on the swivel spindle, as before mentioned, and thus firmly hold the
swivel in position until the catches are liberated as herein-after described. I form
about midway on the inner face of each of the before described catches, at the bottoin
of the notched recesses already mentioned, a triangular projecting tooth. The faces
of each of these projecting teeth are bevilled off in such a manner that when the
catches are closed a conical opening is formed, thus retaining the taper plug presently
described.

page_text: I next fit to the bottom of the hook a second iron swivel or shackle to which the
cage or bucket is made fast. The spindle of this lower swivel extends upwards
through the centre of the box or casing before mentioned, and on the upper part of
such spindle is formed a suitable boss or flange, which, resting upon a suitable
projection formed on the inner base of each catch, thus firmly upholds such lower
swivel. The centre of the boss is made hollow so as to receive a helical or other
suitable spring, which while the catches are closed depresses a loose taper metal plug
corresponding externally in shape with the angle of the internal projecting teeth
formed midway on the catches as before described.
In one of the cross heads of the head gear of the mine or pit I securely fix in
any suitable manner a stout iron ring or socket head, on the inner face whereof is
formed three or any other suitable number of parallel projecting rings which serve
as catches as hereafter described.
The operation of my Invention is as follows:-When the detaching hook is in its
ordinary working order the movable catches are kept closed by means of the keys
before described. Should however the rope or chain be overwound, either the
external projecting teeth formed on the tops of the catches, or the box or casing
holding the movable parts of the hook, comes into violent contact with the lowest
projecting ring or catch formed on the ring or socket head fitted into the cross head,
as just described, thus forcing the keys which keep the catches closed downwards,
and severing the metal pins by which such keys are held in position. By this means
the catches are liberated, thus releasing the taper plug, which, being forced up by
the action of the spring contained within the spindle of the lower swivel, forces such
catches out, and causes them to gear into and rest upon one of the internal parallel
projecting rings or catches formed on the inner face of the iron socket head or ring
before mentioned, and so as to firmly support the bucket or cage, the swivel to which
the rope or chain is attached being liberated by the release of the catches, and going
away with the rope.
In order to reconnect the book for lowering back I pass the flange of the top
swivel between the jaws of a suitable supplementary link or shackle where it is
held by two cross pins. Two of the catches first described are then passed between
four links, which are suspended loosely from a cross belt placed at the bottom of
the supplementary shackle, and these links are secured to the catches by suitable
cross pins.
When the catches are so connected they at once collapse, whereby the internal
middle teeth, again pressing on the taper plug, force down the spring, and the cage or
bucket can at once be lowered with safety.