Abstract:
Various hoisting systems with anti-two-block sensing devices are provided. In one embodiment, an apparatus includes a crane having a hoisting line and an anti- two-block sensing device installed about the hoisting line. The anti-two-block sensing device includes an upper chandelier, a lower trigger assembly suspended from the upper chandelier, and a detector positioned to detect movement of the lower trigger assembly with respect to the upper chandelier. The lower trigger assembly can include two plates each having a hoisting line aperture and a slot that allows transverse installation of the plate about the hoisting line. Further, the two plates can be positioned such that their slots are offset from one another and the plates cooperate to fully surround the hoisting line. Additional systems, devices, and methods are also disclosed.
Abstract:
The invention relates to a method for controlling a crane, the method comprising controlling a rope part (13) connected to a hook of the crane with a friction- operated driving wheel (3), extra rope (12) being coiled into a plurality of layers onto a storage reel (4). In the method, two machineries (1, 2) are used, of which the first (1 ) is intended for the driving wheel (3) and the other (2) for the storage reel (4), one machinery (1, 2) being controlled with a speed instruction and the other machinery (1, 2) with a torque instruction.
Abstract:
A control system for controlling the operation of a plurality of modular lifting units (12). The control system includes a power source (20) for providing power to each of the modular lifting units (12). A main control box connected between the power source (20) and the modular lifting units (12), comprises a mode switch (28) for switching the system between two control modes: a group mode, in which the plurality of modular lifting units (12) is controlled synchronously as a group; and, an individual mode, in which any one of the modular lifting units (12) is controlled independently of the other units. In group mode, synchronous movement of the modular lifting units is achieved by setting each unit to run at the same speed. The control system may also comprise one or more power extension control boxes (PECBs) (13) connected between an additional power source and a plurality of additional modular lifting units
Abstract:
A method according to the invention of controlling a rotation speed of a motor of a speed-controllable hoist drive comprises receiving a lift speed instruction (ώ'm )\ forming a final speed instruction (ώm ) by using initial information con- taining the lift speed instruction (ώ'm ); and using the final speed instruction (ώm ) as a speed instruction for the rotation speed of the motor of the speed- controllable hoist drive. The method further comprises monitoring a position derivative of an actual value of a cable force (dF/dz). The initial information for forming the final speed instruction (ώm ) comprises the position derivative of the actual value of the cable force (dF/dz).
Abstract:
The invention relates to a method for controlling a crane, the method comprising controlling a rope part (13) connected to a hook of the crane with a friction- operated driving wheel (3), extra rope (12) being coiled into a plurality of layers onto a storage reel (4). In the method, two machineries (1, 2) are used, of which the first (1 ) is intended for the driving wheel (3) and the other (2) for the storage reel (4), one machinery (1, 2) being controlled with a speed instruction and the other machinery (1, 2) with a torque instruction.
Abstract:
A method of stopping a winding machine that hoists and lowers an object prevents abrasion of an electromagnetic brake and a failure to hoist a load. Based on a speed instruction NREF generated by a speed instruction generating circuit NRC, a speed controller ASR outputs a torque instruction TREF to be inputted to an electric motor M and operates the winding machine. To stop the machine, after a brake instruction BR is outputted to an electromagnetic brake directly coupled to the electric motor M, the value of the torque instruction to the electric motor M is controlled to be zero for a predetermined length of time. When the electric motor speed NFB becomes zero, the control of the electric motor M is stopped.