Abstract:
The invention relates to a device for placing a rotor blade of a wind turbine. The device comprises a hoisting means which is placed on a surface and of which a boom rotatable around a substantially vertical rotation axis is provided with at least one hoisting cable. The at least one hoisting cable comprises an attaching means, such as a hoisting hook, to which a rotor blade for placing can be attached via an elongate hoisting yoke mounted on the attaching means, the hoisting yoke extending in a longitudinal direction of the rotor blade. The boom further comprises a guide device which is configured to limit movement of the hoisting yoke in a direction running transversely of the lifting plane and which is connected to the boom by means of a displacing device displaceable along a longitudinal axis of the boom. The device and/or hoisting yoke further comprises means for displacing the hoisting yoke and/or parts of the hoisting yoke in the longitudinal direction of the rotor blade. The invention likewise relates to a method which makes use of the invented device.
Abstract:
A method for reducing resonant vibrations and dynamic loads of cranes (1), whose horizontal and vertical motion of the pay load (38) are controlled by a boom winch (24) controlling the luffing motion of a pivoting boom (16) and a hoist winch (36) controlling the vertical distance between a boom tip (30) and the load (38), and where the method includes the steps of: - determining the resonance frequencies of the coupled crane boom (16) and load (38) system, either experimentally or theoretically at least from data on inertia of the boom (16) and stiffness of at least a boom rope (18), a hoist rope (26), a pedestal (6) and an A-frame (19); - automatic generation of a damping motion in at least one of said winches (24, 36), that counteract dynamic oscillations in the crane (1); and - adding this damping motion to the motion determined by a crane operator.
Abstract:
A method for controlling the orientation of a load (18) suspended from a bearing wire (16) about said bearing wire (16), comprising the following steps: a. -providing a winch arrangement (10), comprising; a master winch (32), at least one slave winch (34) and a winch control system (31), each of said winches (32, 34) having a winch motor (58) and a bi-directional rotational spool (54) with a tagline (40, 42), wherein each tagline (40, 42) is provided with attachment means (44, 46) for attachment to the load (18)and for applying a controlled torque to the load (18) about the bearing wire (16), and wherein the control system (31) comprises tension sensor means (48) for determining tagline tension and spool rotation sensor means (50) for determining spool rotation,and wherein the control system (31) is controllably connected to each winch motor (58) for controlling spool rotation, b. -connecting the attachment means (44, 46) to the load (18), c. -simultaneous rotating the winch spools (54), until preset tagline tensions are sensed in the two taglines by the tension sensor means (48), d. -during horizontal and/or vertical movement of the load (18), rotating, if necessary, the spools (50) with a rotation speed, for maintaining a desired orientation of the load (18), based on the determined tagline tensions, e. -relieving the tagline tension by rotating the spools (50), and f. -disconnecting the attachment means (44, 46) from the load (18).
Abstract:
Ein Portalhubwagen (1) zum Einsatz in Containerterminals und für allgemeine Transportaufgaben hat ein Rahmengestell (2), ein Lastaufnahmemittel (4), das zwischen dem Rahmengestell (2) hängt und mit einer Last, vorzugsweise einem Container (7), verriegelbar ist, eine Hubvorrichtung (8), mittels der Hubseile auf- und abwickelbar sind und das Lastaufnahmemittel (4) vertikal bewegbar ist, und Fahrträger (3), die am unteren Bereich des Rahmengestells (2) angeordnet sind und jeweils eine Vielzahl in einer Reihe angeordneter Räder (11) aufweisen. Um die Lebensdauer der Hubseile zu erhöhen und entsprechend die diesbezüglichen Wartungsintervalle verlängern zu können, wird vorgeschlagen, daß die Hubvorrichtung (8) je Hubseil, mittels dem das Lastaufnahmemittel (4) bewegbar ist, eine Einzelseilwinde aufweist.
Abstract:
The invention relates to a method for controlling swaying and swinging of a spreader in a crane and the load attached thereto, the crane comprising: a trolley (1), hoist gears (2), hoisting ropes (4), on which the spreader (7) is suspended from the trolley (1), auxiliary gears (10) provided with motors and motor control equipment and auxiliary ropes (12), and in which method the forces of the auxiliary ropes exerted on the spreader are controlled by moving the auxiliary ropes using the auxiliary gears by means of torque instructions (T control ) obtained on the basis of the rope forces (F rope ) of the auxiliary ropes and the rotating speed data of the auxiliary gears, and whereby the rotating speed data of each auxiliary gear (10) is formed gear-specifically as the difference between the measured rotating speed (n act ) of the auxiliary gear and the calculated rotating speed (n cal ) of the auxiliary gear.
Abstract:
Damping device (5) for a hydraulic system of a working machine, for damping pressure oscillations in the hydraulic system including a hydraulic cylinder (1), said damping device having a first accumulator (6), having a first preloading pressure P 1 , and a second accumulator (7), having a second preloading pressure Per wherein P 1 2 , said accumulators being in hydraulic connection with the hydraulic cylinder. According to the invention, the first accumulator is connected to the hydraulic cylinder via a first throttle valve (8), which has a flow opening having a flow area A 1 , and the second accumulator is connected to the hydraulic cylinder via a second throttle valve (9), which has a flow opening having a flow area A 2 , wherein A 1 >A 2 . The invention also relates to a hydraulic system including such a damping device.