GB2173005A

GB2173005A - Rope tension detection

Info

Publication number: GB2173005A
Application number: GB08607830A
Authority: GB
Inventors: Johannes Gerhardus Greyling
Original assignee: Vaal Reefs Exploration and Mining Co Ltd
Current assignee: Vaal Reefs Exploration and Mining Co Ltd
Priority date: 1985-03-27
Filing date: 1986-03-27
Publication date: 1986-10-01
Also published as: DE3610203A1; IT8653200V0; SE8601416L; SE8601416D0; FR2579579A1; IT8667250A0; ZW6986A1; IT8667250A1; IT1189637B; BR8601369A; GB8607830D0

Abstract

In hoisting by a rope secured to a drawbar 19, a load cell beam 15 is positioned between a dead eye 17 and the transom 14 of the conveyance being hoisted. There are strain gauges to each side of the dead eye in recesses 21. Signals from the load cell beam are transmitted to the surface by radio frequency. The signals are received and sent to the engine room to indicate the rope tension condition to the driver or to initiate control signals to prevent operation of the winding engine or removal of conveyance arrestors in appropriate circumstances. <IMAGE>

Description

SPECIFICATION Rope tension detection This invention relates to rope tension detection in hoisting systems used in building lift and mine hoisting applications.

It is important to detect a slack rope condition whatever the cause so that the winding engine driver can take appropriate action or automatic trip and over-ride controls are activated.

Similarly overload conditions or any condition where the rope tension exceeds a predetermined maximum should be detected and acted upon.

It has already been proposed to monitor rope tension by means arranged to detect electronically the force applied by the rope on the winder head gear. In this case it is also necessary to monitor the length of the rope so that the mass of the rope can be taken into account in assessing rope tension. In this regard see South African patent No. 82/4009.

In Swedish patent specification No.

82004573 it is proposed to derive electrical signals from load cell devices in the form of links from which the conveyance being hoisted is suspended. The links could constitute elements of weakness in the chain of suspension.

A conveyance winding system in which at the end of a winding rope there is a coupling attached to the rope and the coupling is attached to and below a transom on the conveyance, wherein the system includes a load cell beam between the coupling and the transom, the load cell beam being fitted with load cells arranged to provide signals corresponding to the force exerted between the rope and the conveyance, an electrical circuit on the conveyance arranged to respond to the load cell signals and to transmit transmission signals, and means for receiving the transmission signals and for translating these signals to provide an indication of the rope tension.

The term "transom when used in this specification means a transom or a cross-head on a conveyance from which the rest of the structure of the conveyance depends when the conveyance hangs on a rope.

The translated signals may be arranged to actuate a warning device in the engine room so that the engine driver can take appropriate remedial action. Alternatively the translated signals may automatically control equipment associated with the hoisting operation such as the winding engine or arresting means on the conveyance.

The coupling means would usually include a dead eye in which case the load cell beam has two load cell arrangements positioned symmetrically at either side of the dead eye.

Embodiments of the invention will now be described by way of example with reference to the drawings, in which: Figure 1 schematically illustrates a rope tension detection system in a mine shaft.

Figure 2 shows part of the top of a cage, and Figure 3 is a sectional view of an alternative arrangement to Fig. 2.

Referring first to Fig. 2 a transom of I beam section is marked 14. Attached to the transom 14 by means of bolts 16 is a load cell beam 15. The beam 15 in turn carries a dead eye 17 secured in place by means of screws 18. A drawbar 19 which straddles the transom 14 engages with a pin 20 passing through the dead eye 17. The drawbar 19 is secured to a rope in any conventional manner.

On the beam 15 there are four recesses 21 in which are placed strain gauges (not shown).

The strain gauges are electrically connected to form load cells. A cable 22 powers the load cells and carries signals from them.

The signals from the load cells correspond to the force exerted between the transom 14 and the dead eye 17 and hence to the force exerted between the transom 14 and the rope.

As shown in Fig. 1 the cable 22 leads to an electrical circuit 30 which monitors the signals from the load cells. The circuit 30 has its own battery supply and generates transmission signals carrying the information coming from the load cells. The transmission signals are transmitted by a radio frequency transmitter 31.

Adjacent the head gear of the shaft a receiver 32 is mounted to receive the transmission signals and to supply the information which they carry to a unit 34 in a winding engine room 36. Normally the unit 34 actuates a display (not shown) which is visible to the winding engine driver. He can observe the display and see that the tension in the rope is between predetermined acceptable levels.

The unit 24 may alternatively or additionally be arranged to actuate an alarm or to initiate a control signal to prevent operation of the winding engine or actuation of cage arrestors in appropriate circumstances.

In the embodiment of Fig. 3 the transom is composed of two I beams 40 each carrying a dead eye 17 and a load cell beam 15. A pin between the dead eyes 17 is engaged by a humble hook 41 secured to the hoisting rope (not shown). In this case the signals from the load cells in the beams 1 5 are processed in the circuit 30.

As described above the engine driver is pm vided with a visual indication of the tension in the rope. Very often in practice the system will be simplified to provide a simple indication or winding engine or other cut-out if the rope tension is outside acceptable levels. In that situation the unit 34 is arranged to give actuating signals only when an unacceptable level of rope tension is reached.

Claims

1. A conveyance winding system in which at the end of a winding rope there is a coupling attached to the rope and the coupling is attached to and below a transom on the conveyance, wherein the system includes a load cell beam between the coupling and the transom, the load cell beam being fitted with load cells arranged to provide signals corresponding to the force exerted between the rope and the conveyance, an electrical circuit on the conveyance arranged to respond to the load cell signals and to transmit transmission signals, and means for receiving the transmission signals and for translating these signals to provide an indication of the rope tension.

2. The system claimed in claim 1 including a winding engine room in which the translated signals are arranged to actuate a warning device in the engine room.

3. The system claimed in claim 1 in which the translated signals automatically control equipment associated with the hoisting operation.

4. The system claimed in claim 3 in which the equipment is a winding engine.

5. The system claimed in claim 3 in which the equipment is arresting means for the conveyance.

6. The system claimed in any one of the above claims in which the transmission signals are at a radio frequency and transmitted by a radio transmitter.

7. The system claimed in any one of the above claims in which the coupling means includes a dead eye and the load cell beam has two load cell arrangements positioned symmetrically at either side of the dead eye.

8. A rope tension detection system substantially as herein described with reference to the accompanying drawings.