Year: 1887

page_text: Date of Application, 9th Nov., 1887
Complete Specification Left, 8th Aug., 1888
Complete Specification Accepted, 14th Sept., 1888
I, ROBERT MIDDLETON, of Sheepscar Foundry, Leeds, in the County of York,.
Engineer, do hereby declare the nature of this invention to be as follows:-
It relates, first, to an improved gripping wedge motion which is brought into action
when the rope or ropes break; and, secondly, to the application of a governor and
gear which sets in action a powerful brake, arranged on the principal shaft, whenever
any undue and dangerous speed is reached by such shaft.
A fault in many gripping clutches, relying on studs and pins, is their liability to
break in pieces with the sudden strain when thrown into action. This weakness my
invention overcomes-Again, many accidents occur in which the rope is not freed and
these clutches are of no use-In this case my governor, coupled to the principal
shaft which is then revolving at an unusual speed, releases the brake and arrests the
whichever way it may be travelling.
cage,
I carry out my invention as follows:-My gripping wedges have teeth-or an
equivalent roughness-on their flat faces with which they are to engage with-(what
I shall call) the (guide) rails. Ordinarily they clear these rails but when drawn up
into action, the nose-end of the wedges pointing upwards, the backs of the wedges,
sliding on smooth beds securely fixed in the frame of the cage, thrust the teeth
forward and make them engage with the rails. When once in action the weight of
the falling cage secures them in perfect contact, even if any part of the gear which
first drew the wedges up afterwards gives way. The wedges may be actuated in many
ways; for instance; a weight or weighted-plate, to which the lifting ropes are
attached, may be suspended above the roof of the cage. This plate may in its turn
support the cage, but it is arranged not only free to fall, but is also assisted by springs
which press it towards the cage-roof where the rope or ropes give way. In its fall it
actuates certain levers and rods, in connection with the wedges, and, by which they
are drawn up, or released, into action. Any number of these wedges may be used.
In a hoist-well, where the four corner rails are to be used for guiding only, special

page_text: rails may be arranged, say, on opposite sides, for the wedges to act upon.. Neverthe
less the corner guide rails might have two wedges each, if desired, in addition ;
making say twelve wedges in such an arrangement.
If desired wedges could be made capable of projecting even to the walls of the
well-in case of the rails giving way.
The beds of the wedges may be placed in any position in the cage, but I prefer
them near the roof or near the floor for the sake of their being well backed up.
My Governor and its gear may be arranged as follows-Any suitable governor of
any class may be taken and geared up to the principal shaft on which the brake is
fitted; it must be so arranged as to its revolutions that-whatever speed is considered
and arranged as dangerous-at such speed the said brake shall be released.
A suitable trigger-motion will best release the brake which must be actuated by a
weight or spring, or both. A wedge motion, similar to the gripping wedge first
mentioned might be used Almost any plan will do, but the Governor must trip the
brake into action; because the brake, being a powerful one, will bring all to a
standstill the governor included-Hence a small governor and a powerful brake is
what is required.
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page_text: COMPLETE SPECIFICATION.
Improved Safety Appliances for Lifts, Hoists, and the like..
1, ROBERT MIDDLETON, of Sheepscar Foundry, Leeds, in the County of York,
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:
It relates first to an improved gripping wedge motion which is brought into
action when the rope or ropes break; and, secondly, to the application of a governor
and gear which sets in action a powerful brake, arranged on the principal shaft,-
preferably that which directly controls and bears the weight of the cage,-
whenever any undue and dangerous speed is reached by such shaft.
A fault in many gripping clutches, relying on studs and pins, is their liability to
break in pieces with the sudden strain when thrown into action. This weakness my
invention overcomes. Again many accidents occur in which the rope is not freed and
these clutches are of no use. In such a case my governor, coupled to the principal
shaft which would then be revolving at an unusual speed, releases the brake and
arrests the cage, whichever way it may be travelling.
In order to explain my invention I have annexed two sheets of drawings.-On
sheet 1; Fig. 1 is an elevation of a cage fitted with my gripping wedge gear, the top
levers &c. of which are shown in front view, whilst the wedges are given in side
view; Fig. 2 is the corresponding side view of the same cage showing a side view of
the top gear and a front view of the gripping wedges; Fig. 3 shows the wedges
drawn up into action and shows, also, how the intensified action, due to the weight of
the cage, drives the teeth of the wedges into. the gripping-posts or rails.
Ι
carry out my
invention as follows:-
=
:
My gripping wedges, A, A, have teeth on their flat faces, B, B, or an equivalent
roughness with which they are to engage with the guide or gripping rails or
posts C. C. Ordinarily they clear these rails, as shown in fig. 2, but when drawn up
into action, see fig. 3, the backs of the wedges sliding on smooth beds, D, D, strongly
and securely fixed in the frame (which is a very important matter) thrust the toothed
sides forward and cause them to engage with the rails. The weight of the now falling
cage-or, inore correctly, freed cage-drives the teeth deeply into the posts (pre-
ferably wooden) and secures them in perfect contact-and this even should any part
of the gear which first drew the wedges up afterwards give way.
J
The wedges may be drawn, or thrust, up into action in various ways. For instance ;-
A weighted or heavy plate G, to which the lifting-ropes H, H, are attached, inay be
suspended above the roof of the cage. This plate in its turn supports the cage by
the bolts J, J, but it is arranged not only free to fall but is also assisted by springs,
one or more, say as at K, which springs bears against the top of the bolt K₁ whose
foot is secured to the roof of the cage. Thus apart from gravity, which when all
got into motion would be of little or no use, the plate G is being continually pressed
towards the roof of the cage and only kept apart by the lifting rope or ropes H. If
freed the weighted plate G, in approaching the cage roof actuates certain levers L

page_text: (which have their fulcra at L') the arms L² of which gear with the top of the
rods M, M, which connect up to the wedges. By screws at the foot these wedges are
easily adjusted for clearance between them and the rails C.
Another mode of actuating the wedges would be by fitting them with springs
ready to pull them up-or push them up-the inclined pathways, but kept out of
action by some set trigger which could easily be set free by the moving weight G
when it approached the cage top.
In the arrangement drawn certain chains N are attached to the ends of the
levers L, as shown, these rún under pullies O, and are then attached to the plate G.
The effect of this is that in case the plate G is in any way separated from the body
of the cage the wedges will be drawn up into action and the cage locked against
the rails C.
Ample play or clearance must be given round the bolts J so that the plate G may
be quite free in its "fall."
Any number of wedges may be used, but as a minimum I recommend, two rails-
one on each side of the hoist-well-and a wedge on each side of the rail or guide.
In a well, where the four corner rails are to be used for guiding only, special rails (C)
may be arranged opposite to one another for the wedges to act upon. Nevertheless
the corner guide rails may have two wedges each, if desired, in addition, making say
twelve wedges in such an arrangement. Corner wedges with teeth on two of thoir
sides may be used in some cases; in fact each case must have the wedges arranged
to suit its own peculiarities. If desired, wedges could be made capable of projecting
even to the walls of the well-in case of the rails giving way. The beds of the
wedges (D) may be placed in any position where they can be strongly backed, but I
prefer them near the roof or near the floor for the sake of this strong backing-up.
It must be clearly understood that when the wedges. are once thrown into action no
connection with the actuating gear must be such as to limit their freedom in rising
up the inclined pathways.
I prefer a cage built up of wrought iron, lined with wood, as better able to withstand
a sudden strain,-somewhat as shown.
My governor and gear may be arranged as follows-see sheet No. 2 of the drawings,
fig. 4, which illustrates the general arrangement of this the second part of my
safety gear.
Any suitable governor of any class may be taken and geared up to the principal
shaft on which the brake is fitted; it must be so arranged as to its revolutions that
whatever speed is considered and arranged as dangerous at such speed the said brake
shall be released.
In the arrangement shown is the principal shaft-i.e., by preference, that which
is in direct communication with the ropes H, H and bears the weight of the before-
mentioned cage. Mounted on Q is the brake-drum R, and a bevel wheel S which
actuates the smaller bevel wheel S₁ mounted on the governor shaft T. The governor
balls are shown at T¹ and at T2 is the usual sliding sleeve.. U is the governor lever,
with its fulcrum at U¹, and its outer arm U2 is fitted with a movable balance
weight, U³, for adjusting the governor so that it shall rise to a given position when
the speed fixed as dangerous shall be reached. When this comes about the arm U²
by depressing the near arm V of the trigger-lever, whose fulcrum is at V₁, causes the
other arm V to release the weighted brake-lever W. The Brake may be of any
convenient arrangement so slung that its strap X is ordinarily clear of the drum R.
To assist such slinging, and to allow freedom to the brake strap when put into action,
a yielding attachment may be arranged-say as shown at X'. The brake lever may
be weighted as shown-or springs, or both, may be used. In case any danger is
entertained from the sudden fall of a weighted lever a piston and dashpot may be
used, say as at, Y, and the outlet of this air cushion regulated at Y¹. Such an
appliance would also reduce the chance of any objectionable rebound to a minimum.
The advantages of my trigger arrangement are these:-Both the governor and the
brake, 'tho' working together, are entirely independent. The governor can be tested
by itself, and the brake by itself-there being no fixed connection.

page_text: The exact arrangement of the trigger may be varied to suit any special circum-
stances, but the governor-which must produce the same effect which ever way it is
run round say as the one shown--must trip the brake into action. This is a necessity
because the brake will bring all to a standstill, the governor included. Hence I
recommend a small governor and a powerful brake. Such an arrangement can be,
and should be, tested from time to time by altering the balance weight U³, or
adding an additional one, so that the governor may release the trigger at an
ordinary speed.
By using the two appliances side by side a very valuable safe-guard for a cage is
obtained-Since if the ropes give way the cage will be caught by the wedge
motion, and if anything else goes wrong and a dangerous speed is attained-either
in ascending or descending the brake will be applied. The brake must be strong
enough to hold more than the heaviest load and also the driving power.
I do not bind myself, neither in the case of the wedge, nor its application, nor
in the brake arrangement, to the details shown as each case will require its own
treatment.
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
1 claim is
1. The Gripping-wedge and its gear-with and without the chains N-arranged,
constructed, and operated, substantially as described and shown, with the object &
for the purpose set forth.
2. The Governor and Brake-gear with independent releasing-trigger, arranged,
constructed, and operated substantially as described and shown, with the object and
and for the purpose set forth.
3. The combination in the same hoist or lift of the Gripping-wedge and its gear-
with and without the chains N-together with the Governor and Brake-gear, arranged,
constructed, and operated, substantially as described & shown, with the object & for
the purpose set forth.
Dated this Seventh day of Anonst. 1888