A DEVICE AND A METHOD FOR GUIDING A BELT

Abstract: A device (4) for guiding a band part comprises at least two sets of guiding members (10, 11), which sets are arranged separated in relation to each other in the running direction of the band part. Each of the guiding member sets (10, 11) forms a slit (12, 13) for receiving the band. The slits formed by the guiding members are displaced in relation to each other by an angle so that the band between the two guiding member sets is turned substantially 90 degrees. Furthermore the invention concerns a method to use the guiding member sets to guide the band part running out/running in so that it is turned substantially 90 degrees between them.

Description: A device and a method for guiding a belt TECHNICAL FIELD OF THE INVENTION AND PRIOR ART The present invention relates to a device and a method for guiding a band according to the pre-characterising part of the subsequent claim 1 respective 9. The device for guiding bands according to the invention is possible and advantageous to use together with winches but may also be used in other situations where good band guiding is required. The band guiding device with or without winch is intended, with advantage, to be mounted on a vehicle, but also other mounting is well possible, for ex- ample on moveable objects. In the case of a vehicle motorized land vehicles are intended in the first instance even if vehicles intended for transport on water or in the air are possible. It is known per se to use bands as traction force transmitting elements in winches. The conception band used from now on concerns an element with a width considerably larger than the thickness of the same. In reality the band width is at least two times, suitably five times and preferably at least ten times as large as the band thickness. The band may be manufactured in arbitrary material if the same has the tensile properties and the flexibility as required. For example the band may consist of fibrous textile material, rubber, plastic, metal etc. The band is intended to be stored on the drum of the winch in such a way that the direction of the band width is substantially parallel to the axis of rotation of the drum. A problem with such band winches is that the band regularly is worn on the band edges. This wearing problem is in reality so serious that band winches in the main only are used in situations in which they function as lifting/lowering so that the band extends straight down from the drum, which is substantially horizontally orientated, during influ¬ ence of the gravitation. It is true that band winches also to some extent have been used in other applications but then, as far as is known, in such applications in which the direction of the band running out/running in relative the drum has been substantially perpendicular to the axis of rotation of the drum. In such applications, for example winches mounted on vehicles, where the pull direction regularly is substantially horizontal and where it often is desired to be able to transmit traction forces in directions oblique relative to the axis . of ro¬ tation of the drum by means of the winch, winches operating with ropes or chains have been used. These have in fact fairly easily been possible to guide out from the drum substantially perpendicularly by means of guiding devices suitable for that purpose, from which the rope or the chain, as viewed at away from the drum, has been able to extend in an oblique direction relative to the axis of rotation of the drum. An example of a conventional winch of that sort, operating with a rope, is disclosed in DE-A 2 307 699. Problems related to traction force transmitting elements shaped as bands are not even hinted at therein. Winches operating with bands lead to the advantage that the band may be wound accurately and in a controlled manner onto the drum without such problems as jamming and clamping, which regularly occur if the drum of the winch operates with ropes or chains and the drum simultaneously is a store for the rope or the chain. As said it is however, problematic that the band edges tend to wear out by contact against the side flanges of the drum and against other possible objects or guiding devices situated close to the drum to assist in guiding of the band. As soon as the band extends obliquely relative to the drum one of the band edges is subjected to a risk of being worn. The wear weakens the band and shortens the life time of the band. Specially seriously is the problem of wearing on the band edges in case of motor vehicle mounted winches in which there is regularly a need of exerting traction forces in the band while that the band extends in a direction obliquely to the drum axis, as an example in cases where the motor vehicle is to be pulled away from a stuck state with help of the winch. SUMMARY OF THE INVENTION The purpose with the present invention is to assign ways to obtain a good band guiding without considerable band edge wearing. This purpose is obtained according to the invention by imparting the band guiding device and the method respectively the characteristics which are more closely defined in the characterising parts of the subsequent claims 1 and 9, respectively. The guiding principle according to the invention is consequently based on execution of a turning of the band substantially 90 degrees be- tween the two guiding member sets, whereby the positive effect is reached that the band guiding which is reached in one of the guiding member sets will tend to centre the band in the second of the guiding member sets and vice versa. It is therefore the band turning itself which leads to the band striving to be in the central part of the two guiding member sets, and therefore it is avoided that the band edges is dragging against surrounding elements to an unacceptable extent. In reality the band guiding device will, when it is placed in front of a drum, cause the band to run, all the way from the drum to the guiding member set mostly remote from the drum, substantially without any band edge contact with surrounding elements. Therefore, it is first outside the guiding member set that is situated mostly remote from the drum that the band part is allowed to turn off in a lateral direction. In a practical case of use it is preferred that the guiding members are formed by rotatably supported rolls. According to another characteristic of the invention, the guiding mem¬ ber sets are arranged at a carrier, which is pivotably supported rela¬ tive to a base about an axis which is substantially parallel with the slit between the guiding members in one of the guiding member sets. Further advantageous characteristics and advantages of the subject matter of the invention are described in the claims and in the following description. BRIEF DESCRIPTION OF THE DRAWINGS With reference to the appended drawing, below follows a specific de¬ scription of a preferred embodiment of the invention cited as an exam- pie. In the drawing: Fig. 1 is a schematic view from above of a winch with a guiding de- vice, Fig 2 is a view along the line ll-ll , the band having been removed, and Fig 3 is a perspective and schematic view illustrating a bit clearer how the band is subjected to a turning substantially 90 degrees between two sets of guiding members which are situated in a relative proximity to a drum for the band. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT In Fig 1 a winch is generally denoted 1 . This winch comprises a drum 2, a traction force transmitting element 3 put about the drum, which element is shaped as band, and a device 4 for guiding a band part denoted 5 which is running out/running in relative to the drum. The winch 1 comprises a base generally denoted 6, in relation to which the drum 2 is rotatably supported about an axis which according to Fig 3 is denoted 18. At this base 6 there is arranged a motor 7 for the driving of the drum 2 when the band is pulled in. Further, a brake device may be arranged at the base 6 for locking the drum 2 against rotation if something unexpected occurs. Furthermore the winch has a skidding brake to prevent the drum from rotating too fast during the pulling out of the band. During such pulling out of the band the drum 2 is released from the motor 7. The brake device and the skidding brake may be arranged in the envelope denoted 8. The band 3 is wound on the drum 2 so that the band with its band edges will be lying freely, i.e. without the band edges being exposed to any wearing effect on the drum. The drum presents indeed, with ad- vantage, side flanges 9. These form delimitations in the axial direction concerning the band receiving space of the drum 2. Normally the band is intended to be located between the flanges 9 so that the band edges are not in contact with the latter. Consequently the flanges 9 may, in the example, be designated as normally passive elements, which none the less function as side guides for the band when the band deviates somewhat from the normal position. The guiding device 4 comprises at least two sets 10, 1 1 of guiding members. These sets are arranged mutually separated in the running direction of the band part 5. Consequently one of the sets, here denoted 10, is situated nearest to the drum 2 whereas the set denoted 1 1 is situated mostly remote from the drum. Each of the guiding sets 10, 1 1 forms a slit 12 and 13 (Fig. 2) respec- tively for receiving the band. The slits 12, 13 formed by the guiding member sets are mutually displaced by an angle such that the band in a section 14 situated between the two guiding member sets 10, 1 1 is turned substantially 90 degrees as it appears in Figs 1 and 3. Likewise it appears in Fig 2 how the slits 12, 13 form an angle between them- selves of substantially 90 degrees as viewed in the running direction of the band part 5. The slits 12, 13 extend substantially perpendicu¬ larly to the running direction of the band part between the guiding member sets. By the described pivoting of the band 3 90 degrees in section 14 such a guiding effect on the band is achieved that the same will tend to stay in the central part of the slits 12, 13, that is so that the band edges will not be able to wear against the surrounding elements in an inap¬ propriate extent. The slit 12 in the set 10 is formed by two guiding members denoted 15. The slit 13 in the second set 1 1 is formed by two guiding members denoted 16. The width of the slits 12, 13 is substantially equally large as or only slightly larger than the band thickness. The Iength of the slits 12, 13 is substantially larger than the band width. In other words, the band will have its side edges in a certain distance from surrounding elements when the band is moving in the centre of one of the slits 12, 13. It is preferred that the guiding members 15, 16 are formed by rotatably supported rolls. This will cause a low friction of the guiding device. The longitudinal extent of the slit 12, formed by the guiding member set 10 which is situated nearest to the drum 2, is substantially parallel to the axis of rotation of the drum. A plane, coinciding with a longitudinal centre axis of that slit 13 which is formed by the guiding member set 1 1 situated mostly remote from the drum and extending substantially perpendicularly to the rotation axis of the drum 2, extends substantially perpendicularly to the longitudinal centre axis of the slit 12 formed by the guiding member set situated nearest to the drum. In other words, the shafts of the guiding members 15 in the first set 10 extend substantially parallel with the axis of rotation of the drum 2 while the shafts of the guiding members 16 in the second set 1 1 extend substantially perpendicularly to the axis of rotation of the drum. The free distance between the guiding member sets 10 and 1 1 has to be enough to allow the discussed pivoting of 90 degrees. A very rigid constitution of the band requires a larger distance whereas the dis- tance may be reduced when a soft and easily flexible band is used. The distance between the guiding member sets must not be allowed to be too large since the mutually correlating function of the guiding member sets then is reduced. The guiding device 4 itself comprises a carrier denoted 17. As illus¬ trated in Fig 2 it is possible that this carrier has a tubular configu¬ ration. The cross-section of this tubular configuration may more precisely be a polygon, for example quadrangle. In reality the carrier 17 may have the nature of a box girder or an envelope, in which the guiding members 15, 16 are situated. The outside end of the carrier 17 is open so that the band part 5 may run out of the carrier 17 at that position. At that end of the carrier 17 which is turned towards the drum 2 the carrier is open towards the drum 2 so that the band from the guiding member set 10 may extend to the drum. In Fig 1 is illustrated, according to a possible design, how the carrier 17 is meant to be connected with the base 6 of the winch about an axis 19a. This axis 19a is in the example concentrical with the axis of the drum 18. An essential feature herein is that the pivoting axis 19a of the carrier is substantially parallel with the longitudinal extent of the slit 12 between the devices 15. It is, however, also possible to form the carrier 17 as a separate constructive element, which by a suitable fixing arrangement would be fixed on the vehicle in view or on another object while the base 6 would be fixed on the vehicle by means of other devices. The described components may be integrated as just was described so that the guiding device 4 is included as a unit in the winch 1 regarded in a wide sense. It is emphasised, however, that this should not be regarded as absolutely necessary. Consequently the band guiding device 4 according to the invention may be used for guiding bands in such situations where winches do not occur at all. In such cases the band guiding device is serving to guarantee that the band runs in the intended direction without wearing with its edges against adjacent object. Then the band guiding devices may serve to bring the band to run in a requisite direction, more or less straight. In cases wherein the band guiding device is not intended to be articu¬ lated to a winch base the carrier 17 of the band guiding device may in¬ stead be pivotably supported about an axis 19b which extends sub¬ stantially parallel with the longitudinal direction of the slit 12 between the guiding member 15 in one of the guiding member sets 10. Then it is preferred that the axis 19b is not only is parallel but also concentric with said slit 12. In the case of guiding members shaped as rolls 15, the axis 19b is, consequently, with advantage placed half-way be¬ tween the axes of rotation of the rolls 15. A pivotable arrangment of the carrier 17 about the axes 19a and 19b respectably is above all desirable with regard to the position where the band runs out from the band guiding device and the band end is con¬ nected to an object, at which traction forces are to be applied whereas the band direction may vary considerably between said object and the band guiding device. In other situations again a pivotable arrangement of the carrier 17 is not required but it may instead be fixedly arranged. By using the described winch the operator is able to pull the band in at pleasure. When the band is to be fed out the drum 2 is released and further, a traction force is applied in the band so that the band is pulled out. When the band is pulled in the guiding member sets 10 and 1 1 will cooperate in such a way that the band is accumulated centered on the drum 2 and during its running from the guiding member set 1 1 , passing the guiding member set 10 and to the drum 2, the band edges are not in contact with elements at the side of the band in a wearing way. Therefore the wear of the band is substantially reduced. During pulling in the band by means of the drum 2 the carrier 17 and there¬ fore also the two sets 10, 1 1 of guiding devices will be able to pivot about the axis 19a or 19b depending on the design and depending on the band direction from the band guiding device 4 to the object, on which the traction force is to be applied. More precisely, the carrier 17 is able to pivot in a vertical plane when the drum 2 is horizontally ar¬ ranged. In this connection it is pointed out that the band guiding device 4 of course may be orientated in different ways in the space. As an example it may be orientated with the slit 12 extending substan¬ tially vertically. To bring the band into the guiding device 4 it is in general necessary to split the same, for example by unfastening a roll. In use, the band easily becomes muddy or in another way dirty. It is therefore suitable to provide the device with a wiper which by contact to the band releases the band from contaminations before the band by the in-pulling will get into contact to the guiding member set 1 1 . The invention is of course not only limited to the above described embodiment, but also other modifications are possible within the field of the basic idea of the invention. It is pointed out that the winch may be used in arbitrary orientations, e.g. for lifting operations.

Claims: Claims 1 . A device for guiding a traction force transmitting element (3) shaped as a band, characterized in that the guiding device (4) comprises at least two sets of guiding members (10, 1 1 ), which sets are arranged mutually separated in the band running direction, that each of the guiding member sets forms a slit (12, 13) for receiving the band, and in that the slits (12, 13) formed by the guiding members are mutually displaced by an angle such that the band (3) between the two guiding member sets (10, 1 1 ) is turned substantially 90 degrees. 2. A device according to claim 1 , characterized in that the width of the slits (12, 13) is substantially equally large as or only slightly larger than the band thickness. 3. A device according to any previous claim, characterized in that the Iength of the slits is larger than the band width. 4. A device according to any previous claim, characterized in that the guiding members (15, 16) are formed by rotatably supported rolls. 5 A device according to any previous claim, characterized in that the guiding member sets (10, 1 1 ) are arranged on a carrier (17), which is pivotably supported about an axis (19a, 19b) relative to a base (6) which is substantially parallel to the slit (12) between the guiding members (15) in one of the guiding member sets (10). 6. A device according to claim 5, the band being retractable with a winch (1 ) comprising a drum (2), about which the band is laid, charac¬ terized in that the longitudinal extent of the slit (12), formed by the guiding member set (10) situated nearest to the drum, is substantially parallel to the axis of rotation (18) of the drum (2). 7. A device according to claim, 5. characterized in that the pivot axis (19a, 19b) of the carrier (17) extends substantially parallel with and between shafts of the guiding members (15) in one of the guiding member sets (10). 8. A device according to claim 6 or 7, characterized in that a plane which coincides with a longitudinal centre axis of the slit (13) formed by the guiding member set (1 1 ) situated mostly remote from the drum (2) and extending substantially perpendicularly to the axis of rotation of the drum (2) also extends substantially perpendicularly to the longitudinal centre axis of the slit (12) formed by the guiding member set (10) situated nearest to the drum. 9. A method of guiding a traction force transmitting element (3) shaped as a band, a device (4) being arranged for guiding a band part running out/running in relative to the drum to a central position in the guiding device for avoiding destructive contact between the band edges and surrounding elements , the guiding device (4) comprising at least two sets of guiding members (10, 1 1 ) which sets are arranged mutually separated in the running direction of the band part, each of the guiding member sets forming a slit (12, 13) for receiving the band, character¬ ized in that the band part, which is running out/running in, is guided by the guiding member sets (10, 1 1 ) so that it is turned substantially 90 degrees between them. 10. A method according to claim 9, a winch comprising a drum, about which the band is laid, characterized in that carrier (17), which carries the guiding member sets during operation of the drum, is allowed to turn relative to a base (6) about an axis (19a, 19b), which is substan- tially parallel to the slit (12) between the guiding members (15) in the set nearest to the drum.

Inventors: HELLENBERG BERTIL, HELLENBERG, BERTIL
Applicants: HELLENBERG BERTIL, SEPSON AB, HELLENBERG, BERTIL
Application year: 1997
Main classification: B66D1
IPC codes: B66D1