Remote-controlled spreading wedge with magnets for sensory position detection

Abstract

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).

Description

[0001] A remote-controlled expanding wedge (1), in which the threaded spindle (2) is provided with at least two 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 remote-controlled expanding wedge, also known as a felling wedge, for triggering tree felling from a safe distance. A remote-controlled drive unit (5) drives the threaded spindle (2), allowing a wedge (4) located between two barbed plates (6) to extend linearly. The position of the wedge is detected by an electronic sensor to determine the end positions of the wedge and transmit this information to the control electronics of the drive unit.

[0003] There are already various versions of remote-controlled expansion wedges on the market, in which the position of the wedge is detected by 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 records the number of turns of the threaded spindle (2). This allows the electronics of the drive unit (5) to calculate the position of the wedge (4) and stop the movement accordingly when the end position is reached. Technical problem:

[0004] According to the state of the art, the number of rotations is transmitted to the sensor by a bar magnet with the magnetic poles along the longest axis of symmetry. The magnet is embedded horizontally in a carrier disk that is connected to the threaded spindle for a rotationally fixed connection. The sensor is located parallel to the threaded spindle and registers the north-south change of the bar magnet with each rotation of the threaded spindle. The carrier disk is made of a material that is as little magnetizable as possible in order to have as little influence on the magnetic field as possible. However, the materials considered, such as aluminum or stainless steel, offer only low strength. Due to the high vibrations from the drive unit, carrier disks made of these materials cannot be permanently attached to the drive shaft in a rotationally fixed manner, which repeatedly leads to errors in the positioning of the wedge.

[0005] The drive shaft is usually made of an impact-resistant alloy, which, however, changes 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 this problem by using two bar magnets mounted radially in the drive shaft, offset by 180°. One of the north poles and the other of the south pole points outward. This arrangement of the bar magnets allows the sensor to register a clear north-south pole change and thus precisely determine the position of the wedge. No additional support disk is required for the bar magnets.

[0007] The number of magnets is preferably two. 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 pitch are possible.

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

[0010] Another variant is conceivable in which the bar magnets are mounted in a radial alignment in a separate component, which transfers the torque from the drive unit to the threaded spindle. List of reference symbols 1 remote-controlled expanding wedge ( Fig. 1-3) 2 threaded spindles 3 bar magnet 4 wedge 5 Drive unit 6 plate with barbs 7 Carrier disc

Claims

[1] Remote-controlled expanding wedge (1) with an even number of bar magnets (3) which are mounted in a radial arrangement in the threaded spindle (2). [2] Remote-controlled expanding wedge (1) with an even number of bar magnets (3) which are mounted in a radial arrangement in a carrier disc which is connected to the threaded spindle via a rotationally fixed connection. [3] Remote-controlled expanding wedge (1) with an even number of bar magnets (3) mounted in a radial arrangement in a separate component which transmits the torque from the drive unit to the threaded spindle. [4] Remote-controlled expanding wedge (1) with an even number of bar magnets (3) which are fixed in a radial arrangement in a shaft shoulder of the threaded spindle (2), wherein the shaft shoulder simultaneously serves as a shaft shoulder for the bearing of the threaded spindle.

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