A LIFTING DEVICE SUCH AS A LIFTING CART WITH MEANS FOR MEASURING THE WEIGHT OF THE LIFTED LOAD

摘要

In many lifting devices, e.g. fork lifting carts, lift systems are used, in which there is a pronounced non-linear transfer function between the lifting height and the applied lifting force. It can be desirable to determine the weight of the lifted load directly on the device, using but a single pressure sensor (33). It is known that such a measuring can be carried out at a predetermined lifting height, where there is a known value of the said transfer function, but the measurement may be highly inaccurate if the load is under acceleration through the measuring level. The invention provides for means (42) for detecting the lifting height and an associated calculator (44), which is currently informed of the lifting height and the lifting force, and which is programmed with the non-linear transfer function. Thereby the weight measurement can be correct at any height, but the lifting force may vary due to the inertia of the load, when lifted with non-constant velocity, and on that background the calculator is adapted such that operative weighing results are accepted only when they are at rest, e.g. during the periods of rest by a manual pumping up of the forks of a fork lift cart.