Device for sorting logs

Description

Technical area

[0001] The invention relates to a device for sorting logs, namely round wood logs, with a conveyor device having drivers and with ejectors arranged along the conveyor device for the targeted discharge of the logs from the conveyor device into round wood magazines depending on signals from a higher-level control system, wherein at least two ejector pairs connected to one another by means of an axis each have a common rotary drive. State of the art

[0002] A device of the type described above is known from CN 209 109 632 U. This document discloses a device having the features of the preamble of claim 1.

[0003] When sorting, for example, round timber in sawmills, longitudinal transport of the round timber on a conveyor system, namely a conveyor chain, with flights and so-called W-shaped ejectors arranged below the feed and above the return of the conveyor chain has become established in recent decades. These W-shaped ejectors are arranged at designated positions along the conveyor system and ensure that the round timber is pushed off the conveyor chain, which is then sorted and temporarily stored in corresponding round timber magazines. Such a W-shaped ejector forms a pair of ejectors. With, for example, two of these ejector pairs spaced apart in the conveying direction, the logs can be thrown into round timber magazines to the left and right equally as seen in the conveying direction of the conveyor system, with at least two ejector pairs, which are drive-connected to one another by means of a shaft, being assigned to each discharge zone.A pair of ejectors consists of two curved ejector legs which are connected to one another at one end and which are pivotally mounted in the connecting area about an axis parallel to the conveying direction, wherein the two curved ejector legs are designed in such a way that when the shaft is pivotally adjusted with the rotary drive, they can alternately engage around the feed of the conveyor device in such a way that a log is ejected either to the right or to the left of the conveyor device.

[0004] Due to the increased, worldwide use of this technology and the performance improvements associated with the principles of rationalization and cost reduction, weaknesses and limitations in previous mechanical and electrical solutions have been revealed, which are eliminated by the present invention, and with it the possibilities of further performance improvements coupled with trouble-free operation and better process quality, energy savings and CO2 emission reduction are created.

[0005] A known device for sorting logs with a laterally tiltable conveyor device having carriers moved along slideways via traction means is known from DE 2 014 857 A. In this solution, the carriers are tilted at the discharge point. For this purpose, run-up curve pieces are assigned to the slideways, with which the movement path of the carriers can be shifted from a conveying plane into a discharge position raised to one side from the conveying plane. The control of the run-up curve pieces is dependent on a measuring device for the dimensions of the sorted items. Another device, in which the carriers are designed as carriages rolling on the guideway and having a log storage block that can be tilted at the predetermined location for the purpose of discharging the carried logs, is disclosed in DE 30 24 699 A1.

[0006] The following has proven to be a disadvantage with known devices: The logs are often dropped inaccurately. Since the usual, conventional rotary drive of the ejectors is via a motor, gearbox and clutch, the interaction of these components results in unavoidable and necessary play. In connection with the existing inertia and braking moments, a precise, electrical or electronic signal specified by a control program cannot be converted into an equally precise movement of the ejectors, which means that inaccurate and scattered discharge is inherent in the system. Due to the unstable chain run laterally to the direction of pull, logs can accidentally fall from the conveyor, which results in limited working speed and performance of the device.

[0007] A possible conveying speed of the conveyor system, for example, is 3 meters per second [m / s]. Ejectors in conventional systems must reach centrifugal speeds of 2.2 [m / s]. Play in the drive train of the torque-transmitting components causes a variation in the ejector impact time of the order of 0.1 s, which can lead to the unbalanced discharge of logs. This is because premature or delayed ejection not only leads to a displaced discharge into the log magazines, but also causes angular momentum around a vertical axis, which can result in the unbalanced deposit of logs in the magazine compartments and thus blockage of the magazine compartments.A standard discharge with a tolerance of + / - 5 cm is important for transporting logs from the log storage area with an excavator, because the orderly contents of the box are a prerequisite for trouble-free removal and stacking up to 10 meters high on the opposite storage pile. This is especially important for the desired fully autonomous operation of a floor conveyor.

[0008] DE 102013203242 A1 discloses devices for handling objects that serve to create a defined, type- or size-dependent arrangement of objects, in particular piece goods, in a plane. These are grouping devices for creating group arrangements of specific geometrically shaped objects, for example, in the beverage industry, where a certain number of filled beverage containers are combined into bundles for packaging. In principle, such devices are used wherever objects with defined dimensions and shapes are prepared or manufactured and subsequently need to be packaged and grouped for transport or shipping. Description of the invention

[0009] The invention is therefore based on the object of creating a device of the type described above, with which the discharge accuracy of logs from a conveyor device into roundwood magazines and the availability of the system itself are improved.

[0010] The invention achieves the stated object in that the rotary drive is a torque motor whose rotor is directly rigidly connected to the axle and whose stator is arranged in a rotationally fixed manner with respect to the conveyor device, wherein the ejectors are arranged with the rotary drive on the conveyor device, wherein in particular the torque motor is fastened to one end of the axle and a bearing block is fastened to the conveyor device at the other end of the axle, and that the rotor of the torque motor is flanged on the drive side directly to the undiminished torsional cross section of the axle, and that the motor-side bearing of the rotor and thus of the axle is preferably carried out via a journal bearing which is arranged between a journal fixed to the housing and a bearing receptacle of the rotor on the inner circumference of the rotor.

[0011] This achieves incomparably better work results at higher sorting speeds. Due to the zero torsional tolerance in the drive train, the accuracy of dropping logs from a conveyor system into log magazines can be significantly improved. In particular, the increased availability of the system itself significantly simplifies the subsequent work process with floor conveyors, as the logs can be deposited in the magazines without errors.

[0012] Particularly simple design conditions result from the fact that the ejectors are arranged with the rotary drive on the conveyor system, with the torque motor being attached to one end of the axle with a fixed bearing and a bearing block with a floating bearing on the other end of the axle. The rotor of the torque motor is flanged directly to the unreduced torsional cross-section of the axle on the drive side, providing a robust and tolerance-free connection. This allows the magnetic rotary motion to be converted into the ejection pulse without play. The motor-side bearing of the rotor and thus of the axle is provided by a journal bearing arranged between a journal fixed to the housing and a bearing seat of the rotor body on the inner circumference of the rotor.

[0013] A torque motor is a high-pole, low-speed electric direct drive. Torque motors exhibit very high torques at relatively low speeds. Special types include swivel motors, which do not perform a 360° rotation. A torque motor can be considered a servo motor optimized for high torques and can be designed as an external rotor or an internal rotor. The high drive torque enables high accelerations and permits high drive rigidity, since there is no torsional backlash in the ejector drive train according to the invention.

[0014] In order to precisely control the torque motor and thus specify the desired pivoting angle of the ejectors as well as a reliable return, it is recommended that it be equipped with an angle sensor that measures the angle of rotation between the rotor and stator to determine the rotor rotation position. Due to the operating principle of the torque motor, a device according to the invention does not require a mechanical, wear-prone brake, which is replaced by the system's own standstill or braking torque of the torque motor upon polarity reversal of sufficient magnitude. The zero position, which is important for precise ejection, can be reached at any time with pinpoint accuracy and repeatability using the data from the position sensor.Preferably, the logs are pushed off the conveyor device with the ejectors without any angular momentum, i.e. without imparting any angular momentum around the log axis, which is to be ensured in particular by the elimination of toothed strips in the push-off zone, so that no angular momentum is imparted to the log sliding into the magazine even when it slides down.

[0015] In order to determine an exact triggering time for the rotary drive and thus the ejector, the conveyor device can be equipped with at least one position sensor for determining a master position on the conveyor device.

[0016] It is particularly advantageous if the interior of a torque motor housing is filled with a fluid, especially transformer oil, for lubrication and temperature control, and if the housing is optionally equipped with cooling fins for cooling. This creates a device that is easy to temperature-control, has very few moving parts, and is easy to maintain.

[0017] Particularly robust and space-saving conditions are achieved for the conveyor system when it comprises a horizontal I-beam with a connecting web connecting two belts and a conveyor chain supporting the carriers, with the forward and return sections of the conveyor chain arranged above the rotary drive. However, such a conveyor system is not limited to use with the rotary drive according to the invention. However, in conjunction with the invention, a particularly compact design with a low overall height results. This conveyor system creates the necessary space for optimal positioning of the ejection device with ejectors, rotary drive, and axle, as well as its freely accessible assembly and maintenance options.

[0018] If the forward and return sections of the conveyor chain are guided in a space spanned by the belts, with the forward section guided in a forward section on one side and the return section guided in a return section on the other side of the connecting web, this also results in particularly robust and weight-saving construction conditions with a small conveyor cross-section, as all forces can be dissipated by the I-beam. By using a horizontal I-beam as the support for the entire conveyor system, it is possible to easily and inexpensively create the forward and return sections in the tightest of spaces with the most precise guidance of the flights in an impact- and load-resistant form.

[0019] The advance area to the side of the conveyor chain can be equipped with guide rails for the profiles forming the flights. The conveyor chain runs between the profiles, and the flights run or slide on the profiles. The profiles and / or belts also provide lateral guidance for the flights, which significantly improves the smooth running of the conveyor system.

[0020] The return space can be closed off with a sliding guide for the carriers arranged between the belts, whereby the carriers run on the sliding guide, which can prevent sagging of the return. Brief description of the invention

[0021] The drawing shows an example of the subject matter of the invention. Fig. 1 shows a conveyor section of a device according to the invention in an oblique view, Fig. 2 shows an enlarged part of the conveyor device from Fig. 1 in oblique view with discharge guides removed, Fig. 3 a device according to the invention in cross section and Fig. 4 the device in longitudinal section along the line IV-IV from the Fig. 3 . Ways to implement the invention

[0022] The device according to the invention for sorting logs 1, in particular roundwood logs, comprises, among other things, a conveyor device 3 having drivers 2 and ejectors 4 arranged along the conveyor device 3 for the targeted discharge of logs 1 from the conveyor device 3 into roundwood magazines 5. The discharge into the roundwood magazines 5 takes place as a function of signals from a higher-level control system 6, with at least two ejector pairs 8, which are connected to one another by means of an axis 7, each having a common rotary drive 9.

[0023] The rotary drive 9 is a torque motor whose rotor 10 is rigidly connected directly to the axle 7 and whose stator 11 is arranged in a rotationally fixed manner with respect to the conveyor device 3. The rotor 10 is shrunk directly onto an axle stub of the axle 7, i.e., rigidly and directly, without any play, and is mounted in a housing 13 that accommodates the stator 11. This eliminates all possible sources of inaccuracy and creates a highly dynamic and precise system that meets the requirements of precise, repeatable discharge and enables high-speed sorting. Due to its simplicity, it also ensures a long service life and low maintenance requirements, coupled with trouble-free operation.

[0024] To determine the rotor rotational position, the torque motor includes a rotation angle sensor 12 that measures the angle of rotation between rotor 10 and stator 11. The interior of a housing 13 of the torque motor is filled with a fluid, particularly transformer oil, for lubrication and temperature control. The housing 13 is also equipped with cooling fins 14 for cooling.

[0025] To determine a master position on the conveyor 3, the conveyor 3 is provided with at least one position sensor S, indicated in the drawing, which must be positioned at a suitable location. Typically, such a position sensor S, for example a light barrier, is provided in the area of ​​the conveyor start in front of the discharge zones.

[0026] The conveyor device 3 comprises a horizontal I-beam 15 with a connecting web 17 connecting two belts 16 and a conveyor chain 18 carrying the carriers 2, wherein the forward run 19 and return run 20 of the conveyor chain 18 are arranged above the rotary drive 9.

[0027] The feed section 19 and the return section 20 of the conveyor chain 18 are guided in a space spanned by the belts 16, with the feed section 19 being guided on one side in a feed section 21 and the return section 20 on the other side of the connecting web 17 in a return section 22. The feed section 21 is equipped on the side of the conveyor chain 18 with guide rails for profiles 23 forming the flights 2. The guide rails are angle profiles attached at one end to a belt and at the other end to the web. The return section 22 is closed off by a sliding guide 24 for the flights 2 arranged between the belts 16. The sliding guide 24 is formed by a ridge-shaped sheet metal profile that is attached to the edges of the belts and projects into the return section 22.

[0028] The ejectors 4 are mounted on the conveyor device 3 by means of the rotary drive 9, in the exemplary embodiment on the I-beam 15, with the torque motor being attached to one end of the axle 7 and a bearing block 25, in which the axle 7 is mounted, being attached to the conveyor device 3 at the other end of the axle 7. The torque motor and the axle 7 thus form a jointly transverse force-absorbing assembly, which is mounted at one end in the housing 13 and the other end in the bearing block 25. Fig. 4 As can be seen, the rotor 10 of the torque motor is flanged directly to the undiminished torsional cross-section of the axle 7 on the drive side, thus ensuring no weakening of the rotary drive due to a reduction in the cross-section in the drive train. The motor-side mounting of the rotor 10, and thus of the axle 7, is provided by a journal bearing 26, which is arranged between a journal 27 fixed to the housing and a bearing receptacle 28 of the rotor 10 on the inner circumference of the rotor.

[0029] The logs are measured via a roundwood processing system (not shown in the drawing) upstream of the device according to the invention, and, depending on the measurement results, it is determined into which roundwood magazine 5 a log 1 is to be deposited. Thus, a drop-off address is determined for each log.

[0030] Furthermore, the discharge time is calculated to an accuracy of 1 / 1000 of a second depending on the conveying speed or path position of the logs, thus ensuring functionally correct and repeatable discharge into the respective log magazine 5. Precise discharge is ensured by the ejectors 4 and the rotary drive 9 according to the invention, which executes a precise pivoting movement at the right time, at the right speed, and with the right size (approximately 45° pivoting movement) and is then moved back to the zero position within a permitted time window.

Claims

1. Device for sorting trunks (1), in particular logs, comprising a conveyor device (3) having carriers (2) and ejectors (4), which are arranged along the conveyor device (3), for a controlled discharge from the conveyor device (3) into log magazines (5) as a function of signals from a superordinate controller (6), with a common rotary drive (9) belonging to each of at least two pairs of ejectors (8) which are drive-connected to one another by means of an axle (7), wherein the ejectors (4) are arranged at the conveyor device (3) together with the rotary drive (9), characterized in that the rotary drive (9) is a torque motor whose rotor (10) is directly rigidly connected to the axle (7) and whose stator (11) is arranged in a rotationally fixed manner with respect to the conveyor device (3) and in that the rotor (10) of the torque motor is flanged directly to the undiminished torsional cross-section of the axle (7) on the drive side, wherein the motor-side bearing of the rotor (10) and thus of the axle (7) is preferably effected by means of a journal bearing (26) which is arranged between a journal (27) fixed to the housing and a bearing receptacle (28) of the rotor (10) on the rotor inner circumference side and wherein in particular at one end of the axle (7) the torque motor and at the other end of the axle (7) a bearing block (25) is fastened to the conveyor device (3).

2. Device according to claim 1, characterized in that a rotation angle sensor (12) measuring the rotation angle between rotor (10) and stator (11) is associated with the torque motor for determining the rotor rotation position.

3. Device according to claim 1 or 2, characterized in that an interior of a housing (13) of the torque motor is filled with an electrically insulating fluid for lubrication and heat dissipation.

4. Device according to claim 3, characterized in that the housing (13) is equipped with cooling fins (14) for cooling.

5. Device according to one of claims 1 to 5, characterized in that the conveyor device (3) comprises a horizontal I-beam (15) with a connecting web (17) connecting two belts (16) and a conveyor chain (18) carrying the carriers (2), wherein the forward run (19) and return run (20) of the conveyor chain (18) are arranged above the rotary drive (9).

6. Device according to claim 5, characterized in that the forward run (19) and return run (20) of the conveyor chain (18) are guided in a space spanned by the belts (16), wherein the forward run (19) is guided on one side in a forward run space (21) and the return run (20) is guided on the other side of the connecting web (17) in a return run space (22).

7. Device according to claim 6, characterized in that the forward run space (21) is provided laterally of the conveyor chain (18) with guide rails for profiles (23) forming the carriers (2).

8. Device according to claim 6 or 7, characterized in that the return run space (22) is closed off with a sliding guide (24) for the carriers (2) arranged between the belts (16).