Remote-controlled spreading wedge with magnets for sensory position detection

Abstract

2.1 Known systems use a horizontally arranged bar magnet in a carrier disk. This design leads to magnetic interference from the usually ferromagnetic drive shaft, as well as to strength problems of the non-magnetic carrier disks, which cannot permanently withstand the vibrations occurring during operation. As a result, the sensor can no longer reliably detect the polarity reversal, leading to faulty position signals. 2.2 The invention provides for the arrangement of at least two radially arranged bar magnets, offset by 180°, in the threaded spindle or in a rotationally fixed component. This ensures that each magnet has a north or south pole facing outwards, allowing the sensor to detect a distinct pole change per revolution. A separate carrier disk is thus unnecessary, and both magnetic interference and strength problems of known designs are avoided. The wedge position is therefore reliably and safely determined. 2.3 The invention is used in remote-controlled spreading wedges, in particular in motorized felling wedges for safe tree felling from a distance. It is suitable wherever precise positioning of a linearly extending wedge is required.

Description

[0001] A remotely controlled spreading wedge (1) in which the threaded spindle (2) is provided with at least 2 magnets (3) which are used by a sensor to determine the position of the travel path of the wedge (4).

[0002] The present invention relates to a remotely controlled spreading wedge, also known as a felling wedge, for triggering the felling of trees from a safe distance. A remotely controlled drive unit (5) drives the threaded spindle (2), which allows a wedge (4), located between two barbed plates (6), to extend linearly. The position of the wedge is detected by an electronic sensor in order to determine the end positions of the wedge and transmit them to the control electronics of the drive unit.

[0003] Several versions of remote-controlled wedges are already available on the market, where the wedge's position is detected via a sensor. Two basic designs are known: 1. The drive unit moves axially along guide rails and is stopped in the end positions by the sensor. 2. The sensor detects the number of rotations of the threaded spindle (2). Based on this, the electronics of the drive unit (5) can calculate the position of the wedge (4) and stop the movement accordingly when the end positions are reached. Technical problem:

[0004] In the current state of the art, the number of rotations is transmitted to the sensor via a bar magnet whose magnetic poles lie along the longest axis of symmetry. The magnet is horizontally embedded in a carrier disc that is rotationally fixed to the threaded spindle. The sensor is located parallel to the threaded spindle and registers the north-south reversal of the bar magnet with each rotation of the threaded spindle. The carrier disc is made of a material with as little magnetizability as possible to minimize its influence on the magnetic field. However, suitable materials such as aluminum or stainless steel offer only low strength. Due to the high vibrations from the drive unit, carrier discs made of these materials cannot be reliably and permanently fixed to the drive shaft, resulting in recurring errors in the positioning of the wedge.

[0005] The drive shaft is usually made of an impact-resistant alloy, which, however, alters the magnetic field in such a way that a north-south change of the horizontally arranged magnet is not detected by the sensor. Purpose of the invention:

[0006] The invention solves the problem by using two bar magnets mounted radially and offset by 180° in the drive shaft. The north pole of one magnet and the south pole of the other point outwards. This arrangement of the bar magnets allows the sensor to register a distinct north-south pole reversal and thus precisely determine the position of the wedge. No additional mounting disc for the bar magnets is required.

[0007] Preferably, two magnets are used. However, any other even number of magnets can also be used.

[0008] Preferably, the bar magnets are offset from each other at the same angle. Deviations from this spacing are possible.

[0009] Preferably, the bar magnets are mounted directly in the shaft in a radial orientation. However, arrangements on a separate carrier disc are also conceivable, in which the bar magnets are likewise mounted in a radial orientation and which has a rotationally fixed connection to the threaded spindle. In this arrangement, high-strength materials can also be used for the carrier disc, which are suitable for a rotationally fixed connection under high vibration conditions.

[0010] Another option is conceivable in which the bar magnets are mounted in a radial orientation in a separate component, which transmits the torque from the drive unit to the threaded spindle. Reference symbol list 1 remote-controlled spreading wedge ( Fig. 1-3) 2 threaded spindles 3 bar magnets 4 wedge 5 Drive unit 6 plates with barbs 7 Carrier disc

Claims

Remote controlled spreading wedge (1) with an even number of bar magnets (3) which are fixed in a radial arrangement in the threaded spindle (2). Remote controlled spreading wedge (1) with an even number of bar magnets (3) which are mounted in a radial arrangement in a carrier disk which is connected to the threaded spindle via a rotationally fixed connection. Remote controlled spreading wedge (1) with an even number of bar magnets (3) which are mounted in a radial arrangement in a separate component which transmits the torque from the drive unit to the threaded spindle. Remote controlled spreading wedge (1) with an even number of bar magnets (3) which are attached in a radial arrangement in a shaft shoulder of the threaded spindle (2), the shaft shoulder simultaneously serving as a shaft shoulder for the bearing of the threaded spindle.

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