Abstract: A fast height-adjustable equipment stand, particularly for a notebook or for a monitor with a keyboard, which can be placed on a table and a support surface of which can be raised or lowered so low that a keyboard situated on the support surface can be operated without difficulty while sitting. To this end, at any height the equipment present thereon is held in a horizontal or defined oblique position such that the support surface is guided by at least two folding brackets, which cause a parallel guidance of the support surface relative to the base surface in that the edges thereof are fastened non-parallel to each other to the support surface in an articulating manner, and that the support surface can be locked in one or more heights to prevent accidental lowering.

Abstract: A fast height-adjustable equipment stand, particularly for a notebook or for a monitor with a keyboard, which can be placed on a table and a support surface of which can be raised or lowered so low that a keyboard situated on the support surface can be operated without difficulty while sitting. To this end, at any height the equipment present thereon is held in a horizontal or defined oblique position such that the support surface is guided by at least two folding brackets, which cause a parallel guidance of the support surface relative to the base surface in that the edges thereof are fastened non-parallel to each other to the support surface in an articulating manner, and that the support surface can be locked in one or more heights to prevent accidental lowering.

Abstract: An electric power supply system with at least two mains (10, 12, 14) is indicated, whose outputs (16, 18, 20) are switched in parallel and who together supply a load (22). The output power of the respective mains (10, 12, 14) is governed by its temperature. In a special execution the output power of the respective mains (10, 12, 14, is regulated by the difference of its temperature and the mean temperature of all mains. This results in the fact that the mean time between two failures of the electric power supply system is increased by simple means.

Abstract: A circuit is described for recognition of two-tone compound signals of two frequency ranges (F1 to F4, F5 to F8) in telephone installations with a limited transmission band width. Band pass filters (11, 12) whose output signals are added up and weighted individually are provided in a number corresponding to the number of possible single tones. The weighted output signals are each compared with the output signal sum of one of two frequency ranges (F1 to F4, F5 to F8 ) in order to signal a valid single tone. To increase the certainty of speech, another summand (Su, So) that is derived from a summation of the output signals of at least two other band pass filters (13) whose mid-band frequencies (F9 to F11) are outside the two frequency ranges (F1 to F4, F5 to F8) is also sent to the summation circuit.

Abstract: An artificial joint for implantation into the living body comprises a head portion adapted to be anchored in one bone of the body and a socket portion adapted to be anchored in another bone. One of the head and socket portions includes a permanent magnet and the other portion either a magnetizable element or another permanent magnet. The two interacting magnetic elements may be polarized for either attraction or repulsion. The head and socket portions are shaped to permit translatory movements relative to each other in addition to rotary movements of the head portion about at least one axis of rotation.