Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
  • G01G19/14—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for weighing suspended loads
  • G01G19/18—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for weighing suspended loads having electrical weight-sensitive devices
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G23/00—Auxiliary devices for weighing apparatus
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G23/00—Auxiliary devices for weighing apparatus
  • G01G23/005—Means for preventing overload
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
  • G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
  • G01L5/047—Specific indicating or recording arrangements, e.g. for remote indication, for indicating overload or underload

Definitions

• Safety device for mechanically-motorized devices that work with linkages and / or cables
• the invention relates to a safety device for mechanically-motorized devices which operate with linkages and / or cable pulls, e.g. Devices for moving stage or studio lights, hanging telescopes, pan-graphs, point-hoists etc.
• the safety device now serves to prevent movement of the device carrying the stage or studio lights if there is an obstacle within the stroke of the device.
• Known safety devices of this type work on the basis of an overload or underload detection. By means of the overload detection, it is determined whether the forces exerted by the movable device exceed a predetermined maximum force. If such a determination is made, the drive device of the mechanical motorized device are stopped or the drive device must not be started. An overload occurs when the device holding the stage or studio lights is to be moved upwards.
• the underload detection it is determined if, during a vertical downward movement of the device holding the stage or studio lights, this downward movement is disturbed by objects in the way. If the device mentioned is moved against objects of this type, the forces exerted by this device on a measuring device are reduced. If such an underload is determined, the drive device of the device holding the stage or studio lights is put out of operation or is not put into operation at all.
• the known safety devices operate on the principle that a mechanical component is deflected in one direction or the other due to overload or underload on the device holding the stage or studio lights.
• This mechanical component which can be a spring, for example, is provided with a release device in the form of a lever, an arm or the like. combined, which in turn actuates electromechanical microswitches when a maximum possible overload is exceeded or when the maximum possible underload is undershot, which are arranged in such a way that they are actuated by the triggering part under the aforementioned conditions.
• this microswitch which is either ON or OFF, is in the control unit of the drive device entered the mechanically-motorized device and the drive device takes out of operation under the aforementioned conditions.
• the mechanical component which is usually designed as a spring, must first be deformed or deflected due to the overload or underload, the triggering part combined with this mechanical component or the spring must mechanically moved, this triggering part must actuate the respective electro-mechanical microswitch, which then inputs its output signal into the control unit of the drive device.
• the invention is based on the object of providing a securing device for mechanically-motorized devices operating with linkages and / or cables, by means of which, on the one hand, a more precise detection of the forces acting on the mechanically-motorized device and, on the other hand, a Compared to the prior art, a faster reaction to an overload or underload condition is possible.
• the securing device has a load measuring device, by means of which a current load, which is exerted by the device which is moved mechanically by means of a motor and works with linkages and / or cable pulls, can be continuously detected and a load signal corresponding to the current load can be continuously generated. Due to the continuous detection of the current load present on the mechanical-motor-operated device, it is possible to initiate countermeasures in the form of switching off a drive device of the mechanically-moved device as soon as this current load rises or falls. Due to the continuous recording of the current load, it is also possible to take countermeasures early, for example in the form of repairs or maintenance, in the event of irregularities which do not yet lead to overload or underload conditions.
• the load measuring device belonging to the securing device according to the invention can expediently have an electrically operating tensile or compressive stress sensor. by virtue of of the tension state determined by the tensile or compressive stress sensor can then be inferred directly to the level of the current load determined by the tensile or compressive stress sensor. Due to the electrical mode of operation of the tensile or compressive stress sensor, an output signal corresponding to this stress state can be generated and forwarded without further intermediate steps.
• a direct response to the output signal of the load measuring device belonging to the safety device according to the invention is ensured if the output signal continuously generated by the load measuring device and corresponding to the current load is input into a control unit of a drive device of the mechanically-motorized device and the drive device can be switched off by means of the control unit or can be kept out of operation if the output signal of the load measuring device exceeds or falls below an upper or lower limit signal.
• the upper limit signal can be determined by a maximum permissible load increase per unit time and the lower limit signal by a maximum permissible load decrease per unit time.
• the load measuring device inputs its output signal into a microprocessor of the control unit of the drive device.
• the measurement or detection of the current load present on the mechanically-motorized device and the generation of an output signal corresponding to this current load can be continuously realized by a single component if the one that forms the load measuring device of the safety device according to the invention electrically operating tensile or compressive stress sensor is designed as a strain gauge.
• the current load leads directly to a change in the operating state of the strain gauge, which at the same time results in a change in the voltage state of a circuit having this strain gauge and thus a change in the output signal of the load measuring device.
• the normal voltage of the strain gauge is associated with an operating state of the mechanically moved device in which there are no faults, such as obstacles or the like.
• the voltage state of the strain gauge changes with a simultaneous change in the output signal of the circuit of the load measuring device having the strain gauge.
• the strain gauge can expediently be arranged on the surface of a spring element. A change in the spring from its normal position thus immediately results in a change in the operating state of the strain gauge and thus a change in the output signal of the circuit of the load measuring device having the strain gauge.
• the strain gauges can be designed as strain gauges whose voltage state, which is proportional to the current load, can be input practically directly as an output signal into the control unit of the drive device of the mechanically moving device.
• the spring element can then be designed in a simple manner as a leaf spring on which the strain gauges are attached in a suitable manner.
• Compression stress sensor as a load cell, e.g. on a piezoelectric basis.
• the load measuring device of the safety device according to the invention should expediently have a load suspension that operates without transverse force.
• strain gauges are used, these can advantageously be components of a bridge circuit, in particular a Wheatston bridge circuit, by means of the an exact detection and evaluation of changes in length of the strain gauges is possible.
• the safety device according to the invention can be used in particular to secure pole lights hangers of a stage lighting, a TV studio or other production facilities for event technology.
• FIG. 1 shows a side view of a securing device according to the invention
• FIG. 2 shows a front view of the securing device according to FIG
• FIG. 3 shows a basic illustration of the connection of the safety device according to the invention to a control unit of a drive device
• FIG. 4 shows a carrying device.
• a safety device serves e.g. to shut down a device for the movement of stage or studio lights if overload or underload conditions occur due to obstacles present in the movement path of the device.
• the safety device according to the invention is integrated in the manner described below in the suspension of the mechanical-motorized device.
• An I-beam 1 is attached in the usual way near a ceiling of a studio.
• a leaf spring 4 is held on the I-profile carrier 1 by means of two screw fastenings 2, which each encompass one leg of the lower base of the I-profile carrier, and an intermediate clamping plate 3, which leaf spring extends in the direction of the main extent of the I-profile carrier 1 via the intermediate clamping plate 3 protrudes.
• a supporting part 6 is suspended from the leaf spring 4 by means of a connecting bolt 5, the arrangement of the connecting bolt 5 with respect to the leaf spring 4 being selected such that a change in the mechanical load on the supporting part 6 results in a large change in the deflection of the leaf ⁇ spring 4 leads.
• steel strips 7 are held on the support part 6, on which a support device 17 shown in FIG. 4 is suspended.
• This carrying device can be moved mechanically and by motor, so that the stage or study lights can be arranged in the desired vertical level within the studio.
• the leaf spring 4 forms, with the strain gauges 8 attached to it, a load measuring device 9.
• the strain gauges 8 are arranged in a suitable circuit, for example in a Wheatston bridge circuit, so that a change in the length of the strain gauges as an output signal by a electrical cable 10 into a control unit 11
• a drive device of the mechanical-motor-driven device holding the stage or studio lights is input, preferably into a microprocessor 12 of this control unit 11.
• the drive device of the device for moving the stage or studio lights is switched off. Since the current load is always known due to the output signal of the Wheatstone bridge circuit 13, this output signal can also be used to detect changes which are above and below an underload or overload condition.
• strain gauges 8 can be arranged in a modification of the illustrated embodiment on each component of the suspension of the device for the movement of the stage or studio lights which is under tension.
• the continuous output signal is proportional to the current load. It is generated permanently so that the drive device can be switched off immediately due to an overload or an underload condition as soon as the current load leaves the permissible range.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)
• Control And Safety Of Cranes (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=7787245

Family Applications (1)

Country Status (5)

Families Citing this family (7)

Family Cites Families (6)

• 1997
  • 1997-03-04 KR KR1019980706946A patent/KR19990087514A/ko not_active Application Discontinuation
  • 1997-03-04 WO PCT/DE1997/000400 patent/WO1997033144A1/de not_active Application Discontinuation
  • 1997-03-04 CN CN97192427A patent/CN1118689C/zh not_active Expired - Fee Related
  • 1997-03-04 EP EP97915330A patent/EP0885378A1/de not_active Withdrawn
  • 1997-03-04 JP JP09531344A patent/JP3142579B2/ja not_active Expired - Fee Related

Non-Patent Citations (1)

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