Improvements in Safety Devices for Colliery Cages, Hoists, and the like.
Year: 1898

page_text: Date of Application, 24th May, 1898-Accepted, 17th Sept., 1898
COMPLETE SPECIFICATION.
Improvements in Safety Devices for Colliery Cages, Hoists,
and the like.
I'
We, ARCHIBALD WILLIAM THOMAS PREST, of 67, Leeds Road, Wakefield,
Draughtsman and ARTHUR TEALE, of 24, Albion Street, Wakefield, Blacksmith,
both in the County of York, 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:
This invention relates to that class of devices used to prevent accident in case
of and due to the breakage of the winding rope, and more particularly to such in
which the breakage of the rope itself operates a gripping or holding device or
rather allows a gripping or holding device to act.
And in order that our invention and the manner in which the same is to be
performed may be more readily and clearly understood, we have annexed hereto
the accompanying drawings of which:-
Fig. 1 is a plan.
Fig. 2 is a vertical section on line A B of Fig. 1.
Fig. 3 is a side elevation corresponding to Fig. 2.
Fig. 4 is a vertical section on line C D of Fig. 1.
Fig. 5 is a part side elevation corresponding to Fig. 4.
Figs. 6 and 7 are views of details hereinafter referred to.
a is a base plate, carrying the mechanism constituting our improved safety
device, and which is intended to be attached to the top of the car or cage by any
suitable means.
A pair of lugs bb are attached to the base plate a, at the centre
of, and close to two opposite sides or edges of the same; in which are pivotted two
sets of gripper arms cc. These extend in opposite directions, each carrying at its
outer end a guide block or slipper d, the form or construction of which is adapted
In the drawings the guides
to the form of the guides for guiding the cage or car.
are shewn as steel wire ropes e, and the guide blocks are shewn as split brackets
with circular holes through them, and through which the four guide ropes e
pass.
Towards its outer end each gripper arm is provided with a bolt hole g, which
in the normal (i.e., horizontal) position of the gripper arm is opposite similar
holes g¹ formed through a pair of lugs h, the latter being secured to the base
plate a.
On the inner side of each pair of gripper arms, and parallel thereto, is
formed a bar i; carrying at each end a locking bolt or pink, guided and supported
at its inner end in a hole formed in a bracket f secured to the base plate a and
at its outer end in the enlarged boss of the lug h: The outer end of the bolt k
passes through the holes and g¹ in the gripper arm c and in the lugs h, being
under normal conditions kept in this position by the pressure of the spring m
against the inner side of the end of the bar i, and thus prevents any movement of
the gripper arms e about the pivots of the lugs b.
Each of the bars i is attached at its centre by means of a lug n and pair of short
links with pin connections to the lower end of one of two curved arms p, the

page_text: curved arms p being pivotted at their upper ends at q between a pair of vertical
standards rr, the latter being secured at their lower ends to the base plate a.
The upper ends of the standards rr are secured together at proper distance apart
by screws ss, passing through them into the distance piece t. The upper end
of the distance piece t is formed as a stud u, on which is fitted and secured by
a nut, a cross bracket ; the outer ends of the latter carrying the depending guide
bolts w.
x is a sliding piece shewn in its highest position at the right-hand side and in
its lowest position at the left hand side of Figs. 2 and 4 formed with a rect-
angular hole through the centre, through which the standards rr and the curved
arms pass; so that the sliding piece can move or slide up and down over the
standards rr. Guide holes are formed in the outer ends of the the sliding piece x,
through which the lower ends of the guide bolts w pass. Springs y under com-
pression are placed round the guide bolts w, between the cross bracket v and the
sliding piece x. Chain brackets z are secured to the outer ends of the sliding
piece, below which they project. In addition to the usual chains from the upper
corners of the cage, two chains pass from the eye bolts 1, 1, of the brackets z. to
the ring to which the ordinary chains are attached; and their length is such,
that when the cage is suspended from the winding rope, the sliding piece x com-
presses the springs y, so far as the enlarged portion of the guide bolts w will
allow; the holes in the sliding piece admitting only the lower thinner ends of
the bolts w. The lower part of each chain bracket is formed with a vertical
slot hole, in which fits one end of a lever 2, pivotted on lugs attached to the
base plate a; the opposite forked end of the lever 2 embracing a cross bar 4,
connecting the outer ends of two of the gripper arms, when the latter are in a
horizontal position: but leaving the bar 4 free, when both the lever 4 and the
gripper arms are tilted sufficiently.
The modus operandi of our invention is as follows.
Under normal conditions, when the weight of the cage is carried by the
winding rope, the locking bolt holds the gripper arms e horizontal, and con-
sequently the axis of the hole in, or the sliding surface of, the guide block is
parallel to the guide ropes or bars.
Should the winding rope however break, either, or both the weight of the
sliding piece and the expansive force of the springs y are free to act, so as
to force down the sliding piece a relatively to the rest of the mechanism described;
whereby the lower ends of the arms p are forced inwards, withdrawing by means
of the connecting mechanism above described, the locking bolts & from the holes
in the gripper arms c; thereby freeing the arms c, so that they can move about
the pivot pins in the lugs b. Such upward movement of the gripper arms c may
be brought about, by the friction of the guide block or slipper against the guide
ropes or bars; by the upward pressure of a spring against the under side of the
gripper arms; or, by the two armed lever 2, the inner end of which is depressed
by the top of the slot in the lower part of the chain bracket z, when the sliding
piece has fallen sufficiently far raising the outer arm of the lever 2, and with
it the cross bar 4, and the attached gripper arms.
In the case of rope guides this movement of the gripper arms not only tends
to draw the guide ropes inwards, but also causes the guide block d to kink or
grip the guide rope, and thus to arrest the fall of the cage.
4
As the raising of all the freed gripper arms by friction against the guide ropes
would not necessarily take place simultaneously, we prefer to use one of the positive 5
acting means above mentioned, to cause such simultaneous rise, and thus avoid
the risk of all the strain being thrown on to one rope.
In the case of rectangular or bar guides, the upward movement of the arms c
may be arranged to stop the fall of the cage either by a gripping jamming or
wedging action, as indicated diagrammatically in Figs. 6 and 7.
As a merely temporary or inadvertent slackening of the winding rope might
withdraw the locking bolt sufficiently far to release the gripper arms, which would

page_text: permit them to be then raised by friction against the guide ropes, we make the
end of the lever 2 forked, so that the gripper arms are pulled down into a hori-
zontal position immediately such temporary slackening of the rope ceases.
Further as there would be a liability, during such temporary slackening of
the rope, of the locking bolt being afterwards pushed home beneath the gripping
arms, we provide a short projection 5 on the underside of each gripper arm,
immediately beneath the hole g, so that such projection prevents the bolt moving
across or past the underside of the gripper arm, unless the hole g is immediately
opposite, or rather unless the gripper arm has been raised much higher than any
temporary slackening of the winding rope would allow, i.e., such as would occur
on the actual rupture of the winding rope.
.
The slackening of the rope when the cage is on the "fallers" or bearers, whilst
being loaded or unloaded, merely withdraws the locking bolt for the time being;
there being no movement of the cage relatively to the guide ropes or bars during
such time, there is only a slight rise of the gripper arms; which are again de-
pressed horizontally by their own weight, or by the lever 2, immediately the
weight of the cage is taken by the winding rope.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. In safety devices for colliery cages and the like the combination of pivotted
arms carrying at their free ends guide or gripper blocks embracing or partially
embracing the guide ropes or bars said arms having each a perforation near
its free end fixed lugs in or against which said arms rest in their normal position
and spring pressed locking bolts arranged to be pressed and held through said
perforations and corresponding perforations through said lugs respectively when
the weight of the cage is carried by the winding rope and to be withdrawn from
said perforations when the rope breaks.
2. The combination with the subject matter of Claim 1, of means for with-
drawing the locking bolts when the rope breaks comprising sliding weight
springs y and hinged levers substantially as set forth and illustrated.
3. The combination with the subject matter of Claim 1 of positive means for
ensuring the simultaneous rise of the gripper arms substantially as herein set
forth.
4. The combination with the subject matter of Claims 1 and 2 of means for
ensuring the return and locking of the gripper arms immediately on the cessation
of any temporary or inadvertent slackening of the winding rope substantially as
herein set forth and illustrated.
5. In safety devices for colliery cages hoists and the like the combination with
a gripping wedging or similar device of a spring pressed sliding piece and hinged
levers, said levers operated by the movement of the sliding piece to withdraw a
bolt or catch so as to set free said gripper wedging or similar device.
6. The general construction and arrangement of the mechanism constituting
our improved safety device for mine cages hoists and the like substantially as
herein set forth and illustrated.