IMPROVEMENTS IN SAFETY OR DETACHING HOOKS FOR THE CAGES OF COLLIERIES, MINES, OR HOISTS
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by William Hewitt at the Office of the
Commissioners of Patents on the 10th February 1881.
WILLIAM HEWITT, of Nostell, in the County of York, Engineer. "IMPROVEMENTS
IN SAFETY OR DETACHING HOOKS FOR THE CAGES OF COLLIERIES, MINES, OR
HOISTS."
This Invention relates to safety or detaching hooks for the ascending cages of
collieries, mines, or hoists.
The detaching apparatus used with an ascending cage to prevent the cage from
being wound over the rope pulley consists of two L shaped levers joined together
at the bottom of the vertical legs thereof, the inside faces of the said vertical legs
are in the same plane but are recessed to admit or retain certain pins or bolts. The
recesses made in the inside' faces (the faces which are brought together) of the long
vertical legs of the L shaped levers are equally divided between the right and left leg;
first, one vertical recess into which fits the shank of the suspending bolt is made at
the top end of the said legs; second, one transverse recess which cuts into the
bottom end of the vertical recess is of the same form and made to admit the
transverse equal sided projection on the bottom end of the said suspending bolt;
third, one transverse recess under and cutting into the second named recess is of
about the same width as a bolt, hereinafter described, the said recess being made
taper for a short distance from the end thereof.
The above described recesses refer to the inside faces of the L shaped levers.
The outside faces of the said levers (the faces opposite to those recessed as above
described) are from the upper edges of the horizontal arms made taper for the
greatest portion of the length thereof, and the said faces are then projected
outwards so as to make the upper ends of the vertical legs of the levers wider than
the lower parts thereof; the two horizontal arms of the levers are drilled to receive
the ring bolts or links of the two chains which suspend the cage.
The pin by which the detaching hook is connected to the rope and which is
secured to the rope and which I call the suspending bolt, has an ordinary eye at
the top thereof and a transverse projecting bead at the lower end thereof, the said
projecting head having at the under side thereof a longitudinal groove of the form
(or thereabouts) in cross section of one half of a bolt which is used therewith. The
CD 077

page_text: recesses at the upper end of the two vertical legs receive the lower part of
the suspending bolt, and the upper part thereof projects above the detaching
hook.
The two vertical legs of the detaching hook are held firmly together during the
ordinary working of the cage in ascending and descending by a hoop or clasp, the
said hoop being of the form internally in horizontal cross section and sliding freely
on the widest portion (the upper portion) of the said vertical legs; the hoop and
vertical legs of the levers where surrounded by the said hoop are so formed as
that the hoop will sustain the pressure of the said legs uniformly throughout. The
hoop is pierced at each side to allow a bolt to pass completely through it, the said bolt
being screwed up securely to the said hoop; this bolt is the one which fits into the
longitudinal groove in the projecting head of the suspending bolt. The hoop is
held in position on the extended portion (the upper portion) of the vertical legs by
copper (or other soft metal) pins which pass through the said hoop and the said
vertical legs or which are otherwise fitted thereto to hold the hoop in position.
The bolt which passes through the hoop and through the groove in the projecting
head of the suspending bolt may be either circular in cross section, or in cross
section the upper portion may be circular, the centre portion flat sided, and the
lower portion taper, or it may be of other convenient form in cross section,
In combination with my improved detaching hook is employed a conical bush,
collar, or hollow flanged plate fixed in a strong frame in the head gear over the
shaft; this collar or hollow flanged plate is placed under the rope pulley, and the
rope to which the cage is suspended passes through it. The hole in this flanged
plate is by preference. made taper, so that when the hook is suspended by and in
the flanged plate, and when consequently the vertical legs of the detaching hook
are opened to their widest extent so as to release the suspending bolt and rope the
legs will lay against the internal taper face of the said flanged plate.
In using my improved detaching hook and when the cage is raised so as the top
end of the hook enters the conical bush, collar, or flanged hollow plate, the hoop
strikes the flanged plate or collar and the copper pins are sheared off, thus releasing
the hoop and forcing it down the vertical legs, carrying with it the pin which is
secured thereto (and which is. in the groove in the projecting head of the suspending
bolt); this pin forces open the vertical legs gradually in its descent until the
projections on the outer faces of the upper ends of the vertical legs are over the top
of the flanged plate, conical bush, or collar, when the suspending bolt is then free to
rise with the rope, and the hook is securely suspended in and by the hollow flanged
plate.