Improvements in Automatic Safety Doors and Gates for Hoists and Lifts.
Year: 1897

page_text: Date of Application, 14th Dec., 1897
Complete Specification Left 14th Sent
1898 Accented 5th Nov
1800
Date of Application, 14th Dec., 1897
Complete Specification Left 14th Sent 1898 Accented 5th Nov
1000
PROVISIONAL SPECIFICATION.
Improvements in Automatic Safety Doors and Gates for Hoists and
Lifts.
We, WALTER MITCHELL and HERBERT MITCHELL, both of Acre Works,
Wibsey, near Bradford, in the County of York, Engineers, do hereby declare
the nature of this invention to be as follows:-
This invention relates to improvements in safety doors, gates or guards for
automatically closing the entrances to hoists or lifts when the cage or hoist is
away from such entrance.
For this purpose we employ for each entrance to the cage or hoist an approxi-
mately vertical sliding door or gate working in suitable guides and provided
with balance weights which also work in suitable guides inside the gates. The
cords or chains connecting the balance weights with the gate pass over guide
pulleys, above the said guides and the latter are wider apart at the top than
the bottom so that each pair of guides is inclined to an appreciable extent from
the vertical in opposite directions. A projection is formed on the top of the
cage or hoist adapted to engage and lift the gate when the hoist reaches the
entrance and projections are also provided upon the top or other convenient
part of the cage or hoist to engage the weights or projections thereon and by
forcing down the weights raise the gate when the cage or hoist comes down,
and the inclination of the gate and weight guides is such that when the cage
or hoist has more or less passed the entrance the gate and weights or the pro-
jections thereon engaging the projections on the cage or hoist pass out of the
path of the latter and are consequently disengaged therefrom.
The projection on the cage or hoist for lifting the gate is hinged or made
with a knuckle joint adapted to allow it to freely pass the gate when descending.
The projections on the weights are also made in a similar way to allow the cage
or hoist to rise without lifting the weights.
Instead of bodily inclining the herein mentioned guides, a more abrupt
inclination may be formed in them at any convenient part sufficiently great to
divert the gate or weights, as the case may be, to the required extent.
Or the projections on the weights may be of such a form and arranged in such
a way that the weight guides retain them in position and slots or openings in
the latter allow these projections to fall or be moved clear of those on the cage
or hoist when required. A' similar arrangement may be employed for the gate.
Dated this 13th day of December 1897.
DRACUP & NOWELL;
Patent Agents, Bradford.

page_text: COMPLETE SPECIFICATION.
Improvements in Automatic Safety Doors and Gates for Hoists and
Lifts.
We, WALTER MITCHELL and HERBERT MITCHELL, both of Acre Works,
Wibsey, near Bradford, in the County of York, Engineers, 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 improvements in safety doors, gates or guards for
automatically closing the entrances to hoists or lifts when the cage or hoist is
away from such entrance.
For this purpose we employ for each entrance to the cage or hoist an approxi-
mately vertical sliding door or gate working in suitable guides and provided
with balance weights which also work in suitable guides inside the gates. The
cords or chains connecting the balance weights with the gate pass over guide
pulleys, above the said guides and the latter are wider apart at the top than
the bottom so that each pair of guides is inclined to an appreciable extent from
the vertical in opposite directions. A projection is formed on the top of the
cage or hoist adapted to engage and lift the gate when the hoist reaches the
entrance, and projections are also provided upon the top or other convenient
part of the cage or hoist to engage the weights or projections thereon and by
forcing down the weights raise the gate when the cage or hoist comes down,
and the inclination of the gate and weight guides is such that when the cage
or hoist has more or less passed the entrance the gate and weights or the pro-
jections thereon engaging the projections on the cage or hoist pass out of the
path of the latter and are consequently disengaged therefrom.
The projection on the cage or hoist for lifting the gate is hinged or made
with a joint adapted to allow it to freely pass the gate when descending.
The projections on the weights or those on the cage engaged by the weights
are also made in a similar way to allow the cage or hoist to rise without lifting
the weights.
Instead of bodily inclining the herein mentioned guides, a more abrupt
inclination may be formed in them at any convenient part sufficiently great to
divert the gate or weights, as the case may be, to the required extent.
Or the projections on the weights may be of such a form and arranged in such
a way that the weight guides retain them in position and slots or openings in
the latter allow these projections to fall or be moved clear of those on the cage
or hoist when required. A similar arrangement may be employed for the gate.
To fully describe our invention reference is made to the accompanying sheets
of drawings forming a part of this specification, in which similar letters of
reference indicate corresponding parts in each of the figures.
Figure 1, represents a front elevation of such portions of a hoist as are neces-
sary to illustrate the application of our improvements. Figure 2, is a cross
section of the same and Figure 3, is a plan view.
Figures 4 to 8, illustrate modifications hereinafter referred to.
Referring firstly to Figures 1, 2, and 3; The gate A is made with side pro-
jections A sliding in the side guides A3, A3 and is connected by the chains A, A+
passing over the pulleys A5, A5 to the balance weights B, B. These balance
weights have projections 132, B2 engaging the side guides B3, B³ and although
not so heavy as the gate do to some extent balance it. In Figure 1 the broken
line C represents the floor line and the lines C, C the sides of the hoist well.
The cage D is shown up to the floor and the gate A is raised to give access to

page_text: the cage. The gate A is prevented from falling by the pawls D2, D3 on the cage
engaging the projections A6, A6 on the gate thus assuming it is required to
lower the cage the gate owing to its being heavier than the balance weights
follows the cage until it reaches the floor and closes the entrance to the hoist.
If however it is required to raise the cage instead of lowering it the pawls D2
raise the gate until the lower projections A2 pass up the inclined portions A
of the guides A³ then the projections A become disengaged from the pawls D³.
Just before this takes place however the lips B4 on the weights B descend below
the noses E of the levers E2 pivoted by the studs E³ to the sides of the cage.
The weighted ends E of the levers rest upon the studs E in the sides of the
cage consequently the noses E will not rise in relation to the cage but are free
to be depressed to allow the lips B to pass them. As soon as the projections A
are disengaged from 12 the gate falls as far as the noses E will permit and it
is then lowered at the same speed as the hoist rises until the gate reaches the
floor. On the reverse movement of the cage the noses E of the levers E2 again
engage the lips B and press the weights downwards until the projections A on
the gate are raised above the pawls D2, D2 then the lower projections B2 on the
weights pass into the inclined portions B5 of the guides B and divert the lower
ends of the weights sufficiently to disengage the lips B from the noses E.
In the modification shown in Figure 4 which represents a similar view to
Figure 2 the gate and weight guides A and B are made vertical and parallel to
each other and the weights have swing pieces 17 pivoted to them. Figures 7
and 8 represent a vertical section and a sectional plan on a larger scale of the
guide B with the weight B in it. The swing piece B is normally held by the
guide B³ in the position shown by the full lines in Figure 7 with its nose B'
rigidly projecting to engage the nose E but at each point where E requires to
disengage B an opening B is made in the back of the guide which allows the
piece B to swing back clear of E as shown by the broken lines Figure 7. An
incline B across the guide may be provided below to assist in diverting B.
The projection A in the arrangement shown in Figure 4 is pivoted to the
lug a on the gate A and is normally held in position to engage D2 by the
spring a², but at each point when it requires to be disengaged from D²
an incline at is fixed to the guide A³ to engage the top of A6 and divert it as
shown by the broken lines in Figure 5, which represents a sectional view of
certain of the parts on a larger scale. Figure 6, is a plan view of Figure 5.
It is obvious that the same result may be obtained by deviating the projec-
tions on the hoist instead of those on the gate and balance weights..
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. The combination with a hoist or lift of a more or less balanced gate auto-
matically operated by projections on the cage and having provisions for deviating
said gate and its balance weight or weights when it is required to disengage
them from the cage, substantially as herein shown and described.
2. The combination with a hoist or lift of a gate and balance weight having
projections or their equivalent adapted to engage projections or their equivalent
on the hoist to automatically operate them, together with means for deviating
the projections on the gate and weight and those on the cage in relation to each
other when it is required to disengage them, substantially as herein shown and
described.
Dated this 13th day of September 1898.
DRACUP & NOWELL,
Patent Agents, Bradford.