Hoisting device with load measuring mechanism and method for determining the load of hoisting devices
A hoisting device, especially a cable or chain block, with a hoisting transmission having at least one shaft and with a hoisting load measuring mechanism. In order to determine the hoisting load as accurately as possible and possibly independent of the reeving and without additional structural height, the hoisting load has at least one sensor for detecting the deformation of the shaft produced by the hoisting load and the detected deformation is used as a quantity in determining the hoisting load.
1. A hoisting device, comprising:
a hoisting transmission having shaft and a hoisting load measuring mechanism;
said hoisting load measuring mechanism having at least one sensor, said at least one sensor detecting deformation of the shaft produced by the hoisting load, wherein the detected deformation is used as a quantity in determining the hoisting load;
wherein said at least one sensor determines the torsion of the shaft;
wherein said at least one sensor for detecting the deformation of the shaft detects the torque;
wherein said at least one sensor comprises a magnetic field sensor;
wherein said at least one sensor works by magnetostriction;
wherein said at least one sensor detects deformation without contact; and
wherein the shaft has at least one zone of permanent magnetization in a region situated opposite said at least one sensor, the magnetization being oriented essentially longitudinal in die direction of the shaft axis, and said at least one zone of permanent magnetization generates a magnetic field outside the region having a magnetic field component in a circumferential direction in relation to the shaft axis, wherein said magnetic held component is detected by said at least one sensor.
2. The hoisting device per claim 1 , wherein the shaft has unit and second zones in said region situated opposite said at least one sensor, said first and second zones being arranged in rings about the shaft axis, said second zone being positioned radially inward from said first zone, while one of said first and second zones has a permanent magnetization, oriented longitudinally in the direction of the shaft axis, and the other of said first and second zones furnishes a return path for the flux generated by said one of said first and second zones, and said one of said first and second zones generates a magnetic field outside the region, having a magnetic field component in a circumferential direction relative to the shall axis, wherein said magnetic field component in is detected by the sensor.
3. The hoisting device per claim 2 including a holder at least partly embracing the shaft for arranging said at least one sensor on the shaft.
4. The hoisting device per claim 3 , wherein said bolder is secured in or on a housing of the hoisting transmission.
5. The hoisting device per claim 4 , wherein the shaft is the shaft of the hoisting transmission with the smallest diameter.
6. The hoisting device per claim 5 including 2 to 8 detectors sensitive to magnetic field for each region of said at least one sensor, said detectors being arranged in general uniformly about the region.
7. The hoisting device per claim 6 , wherein said at least one sensor comprises multiple sensors that are hooked up in a redundant manner.
8. The hoisting device per claim 7 including a signal processing unit, said signal processing unit processing signals from said multiple sensors.
9. The hoisting device per claim 8 , wherein said signal processing unit is included with electronic controls of the hoisting device.
10. The hoisting device per claim 6 , wherein said detectors comprise coils.
11. The hoisting device per claim 1 , wherein said at least one sensor comprises multiple sensors that are hooked up in a redundant manner.
12. The hoisting device per claim 1 , including a signal processing unit, said signal processing unit processing a signal from said at least one sensor.
13. The hoisting device per claim 12 , wherein said signal processing unit is included with electronic controls of the hoisting device.
14. The hoisting device per claim 1 , wherein the hoisting device is one of a cable and a chain block.
15. A hoisting device, comprising:
a hoisting transmission having a shaft and a hoisting load measuring mechanism;
said hoisting load measuring mechanism having at least one sensor, said at least one sensor detecting deformation of the shaft produced by the hoisting load, wherein the detected deformation is used as a quantity in determining the hoisting load;
including a holder at least partly embracing the shaft for arranging said at least one sensor on the shaft.
16. The hoisting device per claim 15 , wherein said holder is secured in or on a housing of the hoisting transmission.
17. The hoisting device per claim 16 , wherein the shaft is the shaft of the hoisting transmission with the smallest diameter.