AU2012234270B2

AU2012234270B2 - Device for automatically pivoting around the paddles arranged on a paddle wheel

Info

Publication number: AU2012234270B2
Application number: AU2012234270A
Authority: AU
Inventors: Holger FRIEBE; Jan Nowak
Original assignee: MAN Takraf Fordertechnik GmbH
Current assignee: Takraf GmbH
Priority date: 2011-03-28
Filing date: 2012-03-28
Publication date: 2015-08-27
Anticipated expiration: 2032-03-28
Also published as: EA022015B1; WO2012130860A1; CN103429822A; BR112013010253A2; DE102011015247A1; BR112013010253B1; DE102011015247B4; AU2012234270A1; EA201300405A1; CN103429822B; ZA201302354B

Abstract

The invention relates to paddle wheels (3) which are equipped with pivotable paddles (1) on the lateral surface or the drum shell. The pivot axis (2) of the paddles lies parallel to the axis of rotation of the paddle wheel (3). According to the invention, the paddles (1) comprise at least one engagement element (10) arranged laterally and projecting therefrom. Furthermore, there is arranged next to the paddle wheel (3) at least one curved guideway (60) into which an engagement element (10) engages as a paddle (1) is guided past laterally, and the curved guideway (60) thus provides a positive guidance of the engagement element (10) along a curved path. As a result of the relative movement between curved guideway (60) and paddle wheel (3) with paddle (1), the engagement element (10) is moved along the curved guideway (60), and consequently the paddle (1) moves from the first pivoting position into the second pivoting position. A wide variety of configurations for the curved guideway (60) are conceivable but, in each case, the entry to the curved guideway must be arranged in such a way that the engagement element (10) of a paddle in the first pivoting position is guided into the curved guideway (60), thus has the same spacing from the axis of rotation of the paddle wheel as the engagement element (10).

Description

1 DEVICE FOR AUTOMATICALLY PIVOTING THE BUCKETS ARRANGED ON A BUCKET WHEEL FIELD OF THE INVENTION The invention relates to a device for automatically pivoting the buckets arranged on a bucket wheel, or receiving parts of a different kind, on bucket wheels tippable in direction of rotation, for use in excavators, loaders, reclaimers and similar machinery. Driven by the existing bucket wheel drive, by means of this device the receiving organs designed as shovels or buckets are tipped depending on the wheel's direction of rotation. Henceforth, the shovels or buckets for this machinery are simply called buckets. BACKGROUND TO THE INVENTION Conveying machinery equipped with bucket wheels, e.g. bridge-type reclaimers in storage and reloading places working in both directions along a longitudinal stockpile, require being provided with buckets which are pivotable or able to act in two directions. In existing constructions this process of unlocking, tipping (pivoting) and locking is performed either manually by the machine operator, or on its own (i.e. self acting). In machines having manually pivotable buckets, hitherto these are set to a fixed working position for the corresponding rotational and working direction, in which position they are fixed and remain in this fixed position with a fixed angle of attack. In manually pivotable buckets, the operators have to deal with the heavy loads of the buckets. Due to the buckets' own weight, the tipping motion is uncontrolled and therefore hazardous. When tipping over, the buckets hit against the load bearing structure of the bucket wheel. To unlock the buckets, the operators have to move into the pivoting area of the buckets, thus running a high accident risk.

la The locks may get dirty and thereby get jammed. Locking may become difficult in the new end position. The amount of time involved for switching all the buckets arranged on the circumference of the bucket wheel is high. The publication DE 25 13 400 C2 discloses a drum reclaimer having buckets which tip by themselves. The buckets are pivoted, and depending on the wheel's direction of rotation, they are fixed in one of the two end positions. Switching from one end position into the other takes place in a self-acting manner depending on the direction of rotation, caused by the resistance exerted by the conveyed material onto the buckets.

The buckets are equipped with blades arranged opposite to each other and are therefore able to receive material in both directions, according to the drum's direction of rotation. The disadvantages of this solution are the wear and tear of the retaining device of the buckets compared to the drum, their encrustation with conveying material, the constant variation of holding force associated with this, and the time of pivoting dependent on it. Furthermore, whenever the rotational direction of the drum changes and the force of the conveying material therefore suddenly acts in the opposite direction, the buckets are jerked abruptly out of the retaining device and, after moving along the pivoting path, latch abruptly into the retaining device on the opposite side unsprung and at full speed. This causes additional wear and tear of the retaining devices. Whenever several buckets arranged in a horizontal line respectively tip over abruptly at the same time, this leads to extreme impact loads acting on the buckets, the drum and its drive. Freely movable buckets are mounted in a pivotable manner on the drum or bucket wheel and may freely swing back and forth between two fixed end stops. Due to this free swing ing motion the free punch of the buckets and the self-acting pivoting into the respective working position for both directions of rotation are enabled. These buckets may be designed for large-volume loads for all conveyed materials and for high material throughput. However, due to the forces of gravity, the cutting force in the stockpile and the weight of the conveyed material, with each rotation of the drum these buckets hit, on the side of the stockpile backwards, hard against the backward end stop(s). After exiting the stockpile and emptying the buckets in the upper area of the drum, due to the forces of gravity these buckets then fall down, during their cycle on the side opposite the stockpile, onto the for ward end stop with a hard bang. This constant swinging with two hard bangs of each bucket per drum revolution causes a great amount of wear and tear of the end stops and buckets, high dynamic loads within the drum and its drives, including cyclical peaks in power consumption of the drive motors. These loads are extremely high when several parallel buckets pivot simultaneously in rows. Structural damage and cracks in the drums and bucket wheels often result from this.

3 The principle of tippable buckets (dump buckets) intended for an excavator's bucket wheel with two directions of rotation and a spring return is known from the patent specification DE 25 43 529. Hitherto, this principle of tippable excavator buckets has not been applied in practice, since it is not technically feasible in the proposed design and the intended effect is questionable in comparison with the disadvantages of design. Disadvantages are the immediate tipping of the excavator buckets into their respective end position and the extreme engagement depth of the buckets when first entering the stockpile, combined with a constant cutting angle. These cause a large amount of material to be received already when the bucket blade enters the stockpile, then to accumulate in the filled bucket as the excavator moves along the stockpile, and to be pushed upward. After the bucket blade exits the stockpile, this material is then carried back against the bucket wheel's direction of rotation. Thus, the intended free punch of the buckets is not attained, and a large amount of unnecessary mechanical energy is introduced into the stockpile. The application of the principle of springily tippable buckets for drum reclaimers having a low engagement depth is not mentioned in the above mentioned patent specification exactly for the disadvantages listed above. SUMMARY OF THE INVENTION It is desirable to propose a device which enables the buckets of a bucket wheel to pivot automatically without having the aforementioned disadvantages of the state of the art. In addition, the device is to enable the locking and unlocking of the buckets at the stops at each end of the pivoting motion. An aspect of the present invention provides a device for pivoting buckets arranged on a bucket wheel having a plurality of buckets, wherein each bucket is pivoted on a pivoting axis parallel to a rotational axis of the bucket wheel, wherein the buckets are placed on the bucket wheel in an end position in which the center of gravity of each bucket is anterior to the respective pivoting axis when seen in the direction of rotation of the bucket wheel, wherein the buckets are nearly symmetrical to a plane of symmetry passing 3a through the respective pivoting axis, each bucket having at least one laterally arranged and projecting engagement element, wherein said device includes at least one curved guideway arranged laterally relative to the bucket wheel in the area of the buckets, wherein the curved guideway is engagable with the engagement element of each bucket as each bucket is moved past the curved guideway in order to pivot the buckets in a controlled manner by means of forced guidance of the engagement element within the curved guideway. The invention relates to bucket wheels equipped with pivotable buckets on their lateral surface or drum shell. The pivoting axis of the buckets lies in parallel to the rotational axis of the bucket wheel. With respect to the bucket wheel's direction of rotation, the buckets may assume two pivoting positions, whereby in a first pivoting position, seen in direction of rotation, the center of gravity of the bucket lies anterior to the pivoting axis, and in a second pivoting position, it lies posterior to it. In this case, the center of gravity of the buck ets lies above their pivoting axis. The device according to the invention for pivoting the buckets enables the buckets to pivot from the first pivoting position into the second one. Often, the buckets are designed to be nearly symmetrical to a plane of symmetry which includes the pivoting axis, to present the same conditions for the changing rotational and working directions, without any need for modifications, manual intervention or locking. For switching the working directions of the buckets, the bucket wheel must not be en gaged with the material to be received. The buckets must be largely empty. According to the invention, the buckets comprise at least one engagement element ar ranged on their lateral surface and projecting from there. This may be, for example in a simple embodiment, a steel pin projecting from the bucket's lateral surface (in the direc tion of the rotational axis of the bucket wheel). Furthermore, there is at least one curved guideway arranged laterally to the bucket wheel, with which curved guideway an en gagement element engages as the bucket is guided past sideways, by which action the curved guideway forces the engagement element onto a curved path. Due to the relative movement between curved guideway and bucket wheel with bucket, the engagement el ement is moved along the curved guideway and consequently the bucket moves from the first pivoting position to the second one. A wide variety of configurations for the curved guideway are conceivable, however in each case the entry to the curved guideway must be arranged in such a manner that the engagement element of a bucket in the first pivot ing position is guided into the curved guideway, therefore having the same distance from the rotational axis of the bucket wheel as the engagement element. Preferably, the exit of the curved guideway is arranged in the same manner, allowing the device to be applied in both directions of rotation. Preferably, the curve is symmetrical with respect to the radius of the bucket wheel at the apex (the point of greatest distance to the rotational axis of the bucket wheel) of the curved guideway. Between entry to and exit of the curved guideway the distance of the curve to the rota tional axis of the bucket wheel increases in such a way that the engagement element and thus the bucket are raised and the bucket pivots. The switching device may therefore be arranged on one or both sides of the bucket wheel, in which case the engagement elements must also be arranged on both sides of the buckets. The variant having both sides is especially suitable for broad buckets. The switching device may be arranged in the upper or lateral area of a bucket wheel, whereby the upper area is preferable. Preferably, the switching device is activated by a movement (hydraulic, manual, electrical, pneumatic or other) which moves the switching device into its working position. In this process, proximity switches and the control of the bucket wheel drive ensure that always the free space between two buckets is targeted. Preferably, the switching device is provided with a locking guideway which assumes the function of actively unlocking and locking the holding elements. Furthermore, it is prefera ble that the switching device be arranged on a movable slide. The arrangement of the guideways in relation to one another ensures the exact timing of this functional sequence. The main advantages of the solution presented in this invention are the simple and robust construction design of the switching and locking mechanisms for the bucket wheels pivot ing by themselves, depending on the direction of rotation. The switching mechanism may be suitably arranged in the upper area of the bucket wheel or drum, which is free from conveying material, as the buckets' own weight is not utilized. Changing the working direction of the whole machine is possible within a much shorter time. It is possible to automate switching the buckets. The availability and productivity of the machine are thereby increased. The operators neither need to move into the pivoting area of the buckets, nor into the working area of the machine, and may only have a supervisory role. The accident risk and the physical effort involved for the operators are reduced consider ably. As the changes to the existing bucket design only affect the lateral surface of the bucket, retrofitting existing machines may be possible in certain circumstances, provided that the required manufacturing qualities have been maintained and the clearance required for mounting the switching device is present.

6 BRIEF DESCRIPTION OF THE DRAWINGS In what follows the invention is illustrated in more detail based on one preferred embodiment and with respect to figures. The figures show: Fig. 1 a bucket wheel equipped with a device according to the invention before sliding in the curved guideway and locking guideway, Fig. 2 the bucket wheel with engaged curved guideway and locking guideway before a bucket has pivoted Fig. 3 the bucket wheel with engaged curved guideway and locking guideway during pivoting of a bucket, and Fig. 4 the bucket wheel with engaged curved guideway and locking guideway with the pivoted (tipped) bucket. DESCRIPTION OF PREFERRED EMBODIMENT On the body of a bucket wheel 3 buckets 1 are arranged in a row spaced at a regular distance to one another. The rotational direction of the bucket wheel 3 is marked by an arrow according to Fig. 2. As shown in the figures each of the buckets 1 is mounted in a pivoting axis 2 on the circumference of the bucket wheel 3. For each of the buckets 1 a first and a second locking pin 4, 5 are intended. In the illustration according to Fig. 2 the first locking pin 4, and in the illustration according to Fig. 4 the second locking pin 5 are operably connected with the upper bucket 1 in the area of the holding elements 12. In the illustration according to Fig. 3, none of the two locking pins 4 and 5 is engaged with the bucket 1. The self-acting tipping of the buckets I takes place in the center of the upper area of the bucket wheel 3. In this area, there is no direct contact with the conveying material even during the work process.

6a As shown in Fig. 1, the device 6 for switching the bucket position is arranged on a module, and movable in relation to the supporting frame 7, on which the bucket wheel 3 is mounted. In fig. I the movement direction is marked with an arrow. For switching to take place, the bucket wheel 3 must not be engaged with the material to be received. The buckets 1 are emptied. By horizontally moving the module with the switching device 6 towards the buckets 1, the switching device 6 is moved to its initial position at the bucket wheel 3, as shown in Fig. 1. In this process, the switching device 6 is moved into position by means of an electrical, hydraulic or other drive. Proximity switches and the control of the bucket wheel drive ensure that always the free space between two buckets 1 is targeted. In this secured end position of the switching device 6, the pivoting of the buckets 1 on the bucket wheel 3 into their opposite end position takes place. The buckets 1 on the bucket wheel 3 are built symmetrically to suit both working direc tions. The lateral surface 11 of each bucket 1 which is facing the device 6 is provided with an engagement element, here executed as a pivot pin 10. In addition, two holding elements, here executed as mating parts 12, are arranged symmetrically beside the rotational axis 2 in the shadow of the blade edge of the bucket 1. The respective locking pin 4 or 5 holds the bucket 1 in one of the two end positions by means of these mating parts. For each of the buckets I two separate locking pins 4, 5 are intended. The locking pins 4, 5 are secured against rotation and kept in the locking position by spring tension. In each of both end positions of a bucket 1, a locking pin, 4 or 5 respectively, is engaged to keep the bucket 1 in place. The second locking pin, 5 or 4 respectively, is not engaged. At the outer ends of the locking pins 4, 5 a tappet is placed, which is likewise secured against rotation and rigidly connected to the locking pins 4, 5. The switching device 6 comprises two components: * one curved guideway 60 for tipping the bucket and * one locking guideway 61 for operating the locking pins 4, 5. These components 60, 61 are formed and positioned in such a manner that in the pro cess of tipping the buckets 1 their particular functions are performed in a planned se quence. The working mode when pivoting a bucket 1 from one end position into the other is as fol lows: Hitherto, the working direction of the bucket wheel 3 has been clockwise. The new changed direction is shown in the illustration according to Fig. 2 by the curved arrow. The a locking pin 4 holds the upper bucket 1 in this position. To pivot this bucket 1 into the other end position, the switching device 6 has to be engaged. It is moved by a linear drive in horizontal direction and parallel to the pivoting axis 2 of the bucket 1 towards the bucket wheel 3 and is retained securely in the end position. The bucket wheel 3 is running at re duced speed. As this happens, first the tappet of the locking pin 4 is guided along the locking guideway 61, and is actively unlocked against the spring tension of a retaining spring. At the time of complete unlocking according to Fig. 3, the pivot pin 10 is already in the curved guideway 60 and is guided within it in such a manner that the resulting movement tips the bucket I over its pivoting axis, and releases it on the other side. Before this release, in a parallel movement the tappet of the new locking pin 5 is guided through the locking guideway 61, so that the locking pin 5 is unlocked before the bucket 1 is released. After the bucket 1 has tipped over, the tappet of the locking pin 5 is guided through the locking guideway 61 in such a manner that the locking of the bucket 1 in the pivoted position takes place by force, since the locking guideway pushes the locking pin into its locking position. This is especially advantageous, if the movement of the locking pin is restricted due to dirt or similar material, and therefore the force of the retaining spring is insufficient to move the locking pin. The retaining spring serves only to secure the locking position. The final situation is shown in Fig. 4. Subsequently, the following buckets 1 are guided through the switching device 6, are tipped over by it, and are locked in their new working position. After all buckets 1 have been moved into the new working direction, the module with switching device 6 is moved away from the bucket wheel 3 into it sresting position. The next switching of the bucket arrangement takes place in the opposite order.

Reference numbers: 1 bucket 10 pivot pin/ engagement element 11 lateral surface 12 mating part/ holding element 2 pivoting axis 3 bucket wheel 4 locking pin 5 locking pin 6 switching device, comprising: 60 curved guideway 61 locking guideway 7 supporting frame

Claims

1. Device for pivoting buckets arranged on a bucket wheel having a plurality of buckets, wherein each bucket is pivoted on a pivoting axis parallel to a rotational axis of the bucket wheel, wherein the buckets are placed on the bucket wheel in an end position in which the center of gravity of each bucket is anterior to the respective pivoting axis when seen in the direction of rotation of the bucket wheel, wherein the buckets are nearly symmetrical to a plane of symmetry passing through the respective pivoting axis, each bucket having at least one laterally arranged and projecting engagement element, wherein said device includes at least one curved guideway arranged laterally relative to the bucket wheel in the area of the buckets, wherein the curved guideway is engagable with the engagement element of each bucket as each bucket is moved past the curved guideway in order to pivot the buckets in a controlled manner by means of forced guidance of the engagement element within the curved guideway.

2. Device according to claim 1 for pivoting buckets having the respective engagement elements arranged laterally in the plane of symmetry, wherein the curved guideway has a slot with a slot width sufficient to allow the engagement element to pass through the slot with clearance, the slot is positioned in the lateral areas of the curved guideway in such a manner that rotating the bucket wheel guides the engagement elements into the curved guideway, curved shape at the center of the curved guideway is for leading the bucket away from the bucket wheel and at the center of the curved guideway is the apex of the pivoting movement of the bucket, wherein the device is positioned such that the distance between the center of the curved guideway and the rotational axis of the bucket wheel is equivalent to the sum of the distance between the rotational axis of the bucket wheel and the 11 pivoting axis plus the distance between the pivoting axis and the engagement element,

3. Device according to claim 1 or 2, including a locking device by which the buckets are fixable in both end positions of the pivoting movement of the bucket.

4. Device according to claim 3, wherein the locking device includes at least one holding element arranged on the bucket and locking elements arranged on the bucket wheel, the holding element being fixable to the locking elements in both end positions of the pivoting movement of the bucket.

5. Device according to claim 4, wherein two holding elements are arranged laterally on the bucket, each of the two holding element engages, in one end position of the pivoting motion of the bucket, with one locking element arranged on the bucket wheel and is fixable to said locking element.

6. Device according to claim 5, wherein the locking elements are locking pins movable in the direction of the rotational axis of the bucket wheel and spring mounted.

7. Device according to claim 5 or 6, wherein the device includes a locking guideway arranged in such a manner laterally to the bucket wheel that the locking guideway, when a bucket moves past the device, opens and closes both locking elements one after the other, so that the bucket is pivotable when the bucket moves past the device.

8. Device according to claim 7, wherein the locking guideway actively moves the locking elements into their locking position.

9. Device according to claim 7 or 8, wherein the locking guideway and the curved guideway are arranged in such a manner, that when a bucket moves past the device, the bucket is first unlocked by means of the locking guideway, then 12 the bucket is pivoted by means of the curved guideway, and after pivoting the bucket is locked ayain by means of the locking guideway.

10. Device according to any one of the preceding claims, wherein the device is movable relative to the bucket wheel between a working position in which the buckets are pivotable by the device, and a resting position. TAKRAF GMBH WATERMARK PATENT AND TRADE MARKS ATTORNEYS P37299AU00