IMPROVEMENTS IN SAFETY APPARATUS FOR HOIST CAGES AND, FOR SIMILAR PURPOSES
Year: 1884

page_text: I ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex
Engineer do hereby declare the nature of this Invention for "IMPROVEMENTS IN
SAFETY APPARATUS FOR HOIST CAGES AND, FOR SIMILAR PURPOSES" and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The hereinafter described improvements in arresting devices for cages, lifts and
similar purposes relate to the employment of movable claws which assuming an
oblique position immediately arrest the cage if the hoisting rope breaks.
In the accompanying Drawings
Figure 1 side-view of the cage.
Figure 2 plan of the same.
Figure 3 detail view of the upper guiding rail.
Figure 4 detail view of the spring for placing the brake claws into an oblique
position.
Figure 5 shows a cage preferably of cylindrical such as used say for hotel lifts.
Figuro 6 plan of Figure 5.
Figures 7 8 9 10 11 show several modifications of the brake claws and of the
spring-device for placing the same in an oblique position.
In Figures 1 2 3 4 A is the frame of the cage made of iron or wood. On the
upper end of the frame A there is the guide rail a forked at its end and
embraces the guiding beams or uprights of the timbering of the well. The
raila has a limited extent of motion in a horizontal direction on the bolt &
so that, when the brake action suddenly takes place or when the claws act,
the upper guide may be able to yield to some extent (Figures 2 and 3). At the
lower part of the cage framing A the brake claws C are mounted so as to
rotate round the bolt d in a vertical plane. They form a double lever one
end whereof is forked and embraces the guide beams or uprights of the timbering
of the shaft whilst the other end is acted upon by the draw-bar g which
is drawn downward by a spring i of sufficient strength. The chains k or
ropes upon which the whole cage is suspended are so attached to the eyes m
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page_text: of the brake-claws C that when the whole apparatus acts correctly the brake
claws C stand horizontally so that the weight of the cage renders the spring i
inoperative. One arm of the brake claws C which as stated form two armed
levers, when in its normal position, that is to say, when placed horizontally, bears
against a striking or abutting piece which prevents its further rotation. The
brake claws can therefore arrive into an oblique position only if the hoisting ropos
or chains & break and the weight of the load aids in holding the same fast. In
no case however can the brake claws turn further during normal working than till
they stand in a horizontal position as the abutting pieces obviate this. In the
upper part of the cage the chains & above referred to are passed over rollers t
united at u and then attached in the well known manner to the hoisting rope or
belt. Now if the hoisting rope, or the chains k break, the brake claws C immediately
assume the inclined position shown in dotted lines in Figures 1 and 9 and jam the
cage against the beam B. What is of importance is that with the increase in the
load the security of the jamming or tightening increases as the brake claws C
always have the tendency to place themselves obliquely and consequently to jam
themselves the tighter the larger the load is. The spring i (Figures 1 and 4) must
be of such force that the brake claws C at once assume an oblique position when
the rope or the claims k break and thus grip. It is advantageous to provide the
lower side of the cage also with a separate guide-rail which may be of a
construction analogous to that shewn in Figure 3 and marked a so that the brake
claws in the present instance serving as guides for the cage may not have too much
work thrown upon them and not wear so soon.
The cage represented in Figures 5 and 6 is analagous in construction with that
shewn in Figures 1 and 2 only the framing A¹ is made of circular shope in plan
and the brake claws C' are so made that each embraces a tube or rod of circular
cross section, B¹, which serve as guides to the cage; a² is a forked guide rail on the
upper end of the cage A'. In this arrangement the brake claws are forced to
assume their oblique position when the rope breaks by spiral springs (Figures 5
and 7). In Figure 8 the spring for placing the brake claws in their oblique position
is replaced by a weight G placed on an extension of the brake claws. Figures 9
and 10 shew the details of brake claw C for a beam B³ of rectangular shape,
and represent these claws both in operation and inactive. Lastly Figure II. shews
how the spring is replaced by an india rubber buffer R.
In all cases the operation of the buffer claws is the same, as by their assuming
an oblique position the cage is securely jammed.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed as communicated to
me by my foreign correspondent I declare that what I claim is
First. A device for arresting the cage of a hoist or lift consisting substantially
of a two armed lever or "brake claw "C pivotted upon the cage body and having
a forked end enclosing the cage guide in its normal condition held clear of the
guides but tending to grip the same, a spring or equivalent device serving to
impart this tendency to the "brake claw" the whole constructed and operating
substantially as and for the purposes hereinabove set forth.
Second. In combination with the "brake claws" C the guide rail a or a
constructed and operating substantially as and for the purpose described and shewn
in the accompanying Drawings.
Dand his 4th of Tann 1001