Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
I
The present invention relates to a device for
measurement and for signal transmission in connection with
hoists and elevators.
Both from the point of view of security and operation,
it is of great interest to be able to monitor the condition of
ropes in hoists and elevators and, in the case of friction
hoists t also the condition of the friction slots which are
located around the periphery of the driving pulley.
There are certain devices at the ropes which are
able, at least during a downtime to measure the rope condition,
but it is more difficult to arrange such monitoring also when
the hoist is in motion.
The invention aims to provide a solution to the
above-mentio~ed problems and other problems associated there-
with. For that purpose, the present invention proposes advice for measurement and signal transmission in a hoist
or elevator including a skip/hoist wage, characterized in
that between a rope or ropes of the hoist or elevator and
the skip hoist cage and/or a counterbalance there
are arranged force measuring means delivering output
signals which are adapted to be supplied to a signal processing
device for obtaining different signals for monitoring
a load in the rope or in the different ropes, also in thy
case ox a hoist or elevator in motion, which signals are
adapted to be transmitted to a monitoring device which
is stationarily mounted in relation to the skip/hoist
cage.
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By such an arrangement a continuous, possibly
multiplexed monitoring of the rope condition can be obtained,
also in the case of hoists in motion.
The objects, advantages and other features of the
present invention will become more apparent from the lot-
lowing non-restrictive description of a preferred embodiment
thereof, made in connection with the accompanying drawings,
in which:
Figure l shows an explanatory sketch of a mine
lo hoist according to the invention;
Figure 2 shows a link in hoist/elevator ropes;
Figure 3 shows the electrical system for the
invention;
Figure 4 which is disposed on the same sheet of
formal drawings as Figures 1 and 2, is an example of the
application of a load or tensile force measuring means; and
Figure 5 is an alternative mine hoist.
Figure l shows a mine hoist, comprising a drum or
driving pulley 4, over which one or several ropes run.
Figure l is a friction hoist and the intention is also to
measure the condition of the friction slots which are to be
found around the periphery of the pulley 4. The hoist also
comprises a hoist cage/skip 5 and a counterbalance 6 as well
as ropes 7, 8. Alternatively, the counterbalance 6 can be
replaced by a second hoist cage or a second skip It is of
great interest to monitor the condition of the ropes 7, 8
and, in case of a friction hoist, also the condition of the
friction slots around the periphery of the driving pulley.
A system consisting of rope force measuring devices
l, 2 is located between the ropes and the hoist cage 5 and
between the ropes and the counterbalance 6, respectively,
and the output signals from these devices l, 2 are processed
and transmitted to a control equipment 3, which can be
employed for a plurality of purposes according to the
US invention.
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The rope force measuring device may, for example,
consist of a strain gauge mounted in a device according
to Figure (see below?, or of a transducer of magneto-
strictive type, semiconductor detectors, or the like.
The link between the force measuring devices and
the hoist cage/the skip and the counterbalance, respective-
lye can be arranged according to Figure 2. Figure 2 shows
the connection to the hoist cage and to the counterbalance,
respectively, at the arrow F, and the hoist cage and the
counterbalance, respectively, are supported by four
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ropes in the shown case which are influenced by the tensile
forces Fly F2, F3 and F4. Between the ropes 9 and the compensating
links 2Q and 21, respectively, there are arranged links 22, the
construction of which is clear From Figure 4. The linkage arrange-
ennui is constructed so as to minimize the effect of uneven load.
figure shows a cast or forged link 22 provided with a window
or recess 23 with a central web or member 24. A number of strain
gouges 25 are arranged in the window adjacent the central web,
said strain gauges being arranged in pairs and being two, four,
six, eight, etc., in number. As mentioned above, it is of course
possible to use other types of transducers as well, and the output
signals from the strain gauges 25 are put together so that a measure
of the respective load or tensile force in the rope (Fluff) is
indicated. The web 24 may be made thicker at the end portions,
whereby the strain will be concentrated at the center of the web.
A rupture on the central web 24 does not involve any safety risk
as far as the winder or hoist is concerned, since, of course,
the rest of the linkage entirely carries the hoist cage or the
counterbalance.
Figure 3 shows the control equipment 3 in the form of a block
diagram, and it comprises a stationary unit I and a movable
unit 27, which accompanies the skip/hoist cage, between which
units there are radio communication ultrasonic communication,
optical communication and/or induction transmission that is,
wireless communication. To save energy normally only the receiver
aye in the movable unit is constantly supplied with voltage whereas
the transmitter unit lob of the control equipment (the movable
unit) requests information via a control signal which also starts
the transmitter lob (via a contact/switch 18~. To save further
energy for example from the battery connected to the movable
unit), the strain gauges 25 are designed with the greatest possible
resistance values.
The hoist cage 5 (the skip) is suspended from a number of ropes
I figure 3), and the load or tensile force in the ropes is
measured according to the above (at 1, I The measuring signal
is amplified at 13 and at 14 there is arranged a measurement ton--
final.
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The output signals from thy measuring devices 1, 2, 25 are supplied
to a calculating device or a processing unit 15, in which, for
example, Fun Jan be computed, where Fun is the rope force -For
no
toe ape n- Also Flax Fin can be computed, i.e. the greatest
d~ff~e~ee button two ropes. If a value of sun or Flax _ Fin
is owned, which is greater or smaller than a predetermined
vowel an emergency stop signal, for example, can be generated.
Dry inlays can ye obtained in the device 15) for example a
signal or the distribution between the loads, maximum or mini-
sum Dow etc.
ye ought signal from the device 15 is possibly supplied to a
multiplex device 16 (switched in at 17) in order to deliver, in
the proper sequence, different signals, representative of the
rope condition, to the transmitter 19b which transmits signals
in a wireless manner to the receiver 19c of the stationary unit,
from where signals are transmitted via a channel selector 20 and
a digital/analog convertor 21, and an output signal is obtained
at 29.
The monitoring device can be completely or partially positioned
on the hoist cage (5) and/or on the counterbalance (6) and/or can
be located outside of these (in a control room or in the vicinity
thereof).
The position of the hoist and the weight of the ropes are derived
from the device 28, and during the calculation in 21 these values
are taken into consideration
From the stationary unit 26 signals can be transmitted to the
ablaze unit 27 (transmitter 19d to receiver aye) in order to
slot the desired signals in the movable unit, to switch in the
receive I (via I and so on.
The hollowing use is of specific interest:
Determination of new load which is obtained from sun, and informal
tin about the hoist depth (see at 28). Net load = Fun - empty
hoist cage - part of lower rope. The information can be used
as a measure of overload, empty discharge, etc.
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Exceeding the maximally permitted uneven load distribution between
ropes This is derived from Flax _ Fin Max n
This results it for example an emergency stop or information
Jo the operating staff.
Load distribu~i~n, which is derived from Fun. This can be used
us i~f~rma~ion about service activities.
Sue of the signals Fun can give dynamic information, for example
byway oscillations in the system, which can be used for control
purples.
If one of the signals on drops below a certain value, for example
because of wedging of the skip, alarm is given.
If Fun from both hoist cages is indicated, this can be used for
optimum start of the drive motor. A driving moment, corresponding
to the torque distribution or the unbalance 9 is applied before
the brakes on the driving pulley or the drum are lifted
The foregoing description has shown two-way communication, whereby
the transmitter on the hoist cage (the skip) can be made to start
transmitting at the command of the control room. It is, however,
possible to save the battery and simultaneously avoid two-way
communication by utilizing the contact or limit switch of the
hoist cage at the end positions of the skip door to generate
making and breaking within a pertain selected time. Otherwise,
the equipment positioned on the hoist cage/the skip is automatically
shut off, and the battery is saved. Switch-on occurs when said
switch is again operated, that is, when the hoist the skip it
used gain.
In those cases where there is no passenger lift cage 7 the equipment
con he activated by pressing the destination pushbutton.
TFanS~lSSiOn of information from the mine hoist 5 to the control
room 3 con tare place by inductive transmission via the steel
hoist rope or via air and radio waves. The damping in the shaft
for radio waves in air is treat.
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To reduce the power consumption and increase the information
content, a change can be made From an inductive system to radio
transmission. To be able to cope with long -transmission distances,
the rope 7 is utilized as a wave conductor (see Figure 5). A
radio ran sitter 30 on the hoist cage 5 transmits via a suitable
aerial 31 to toe rope 7, and with another suitable aerial 32 radio
waves are intercepted and detected in the receiver 3. The numeral
I designates the rope drum, which disconnects radio waves gape-
~itively to a greater or smaller extent and is able to generate
extinction signals and thereby fade-out. This can be eliminated,
for example by transmitting on two or more wavelengths or by sweeping
the frequency of the transmitter and by broadband detecting in
the receiver 3, or by means of two or more aerials (32, 34) post-
toned along the rope. A suitable frequency is 10_60 MHz.
The invention according to the above can be varied in a number
of ways within the scope of the following claims.
