Abstract:
The invention relates to a drive system for transport rollers ( 4 ) in a roller path. According to the invention, said transport rollers ( 4 ) are rotated by drive means ( 14, 34, 52 ). Said drive means ( 14, 34, 52 ) are completely arranged in the interior of at least one support profile ( 2 ) carrying the transport rollers ( 4 ).

Description:
DESCRIPTION 
     The invention relates to a drive system for conveying rollers in a roller conveyor. 
     Roller conveyors, which are used to convey a wide variety of objects, generally comprise two mutually parallel supporting sections that extend in the longitudinal direction of the roller conveyor and between which a multiplicity of conveying rollers is arranged in series. These conveying rollers can be supported in such a way as to rotate freely, i.e. can be undriven, with the result that the objects to be conveyed move on the roller conveyor only by virtue of an acceleration previously imparted to them or, if the roller conveyor slopes, by virtue of their weight. However, roller conveyors of this kind also involve the use of driven conveying rollers to which rotation is imparted externally in order to move an object on the roller conveyor. In this case, all the conveying rollers of a roller conveyor or only certain conveying rollers at regular intervals may be driven, with freely rotatable conveying rollers being arranged between these driven conveying rollers. 
     The conveying rollers generally have a socket in their two longitudinal ends or end faces for an axle or shaft, by means of which they are supported in the supporting sections of the roller conveyor. In the case of the driven conveying rollers, a drive shaft is mounted at at least one end of the driven conveying roller, this drive shaft on the one hand being supported in the supporting section and on the other hand generally having, between the conveying roller and the supporting section, a driving wheel by means of which the conveying roller is driven. These driving wheels are generally chain wheels or gearwheels, which are driven by means of a chain or a toothed belt. In this case, a continuous drive chain or a continuous toothed belt generally extends over a multiplicity of driving wheels of a multiplicity of associated conveying rollers belonging to a conveying group, and these conveying rollers are thus driven jointly. 
     However, this arrangement has the disadvantage that the driving wheels and the toothed belt or drive chain are very close to the actual conveying roller, and there is therefore the risk of contact with objects to be conveyed. Another disadvantage is that the drive system, which is arranged between the conveying rollers and the supporting section, quickly gets dirty, which impairs its operation and increases wear. This drive system furthermore provides poor accessibility, especially when fitting or changing an endless drive belt or a drive chain, since all the rollers have to be removed to do this. 
     It is the object of the invention to provide an improved drive system for conveying rollers in a roller conveyor, in which the drive system is better protected from dirt and any possible contact with objects to be conveyed and provides improved accessibility. 
     The object is achieved by means of a drive system with the features given in claim  1 . Advantageous embodiments will become apparent from the sub-claims. 
     In the drive system according to the invention, the drive arrangements, which drive at least some of the conveying rollers in rotation, are arranged completely within at least one supporting section or profile supporting the conveying rollers. In this way, a fully closed drive system is formed that offers better protection for the drive system from dirt. This closed configuration furthermore reduces the risk that objects to be conveyed or people standing close to the roller conveyor will come into contact with the drive system, thereby reducing the risk of damage to the drive system and to the objects to be transported or of injuries. 
     The drive arrangements advantageously comprise at least one driving wheel for each driven conveying roller, which is connected in a rotationally fixed manner by a shaft to the conveying roller, at least one group of driving wheels being driven by a common driving means. A drive system of this kind allows a simple and economical drive configuration since the conveying rollers can be driven by means of the driving wheels, via belts or chains that run through, for example. 
     The driving wheels are furthermore preferably designed as gear-wheels, which are driven by means of a common driving means in the form of a toothed belt or a chain. A toothed-belt drive or chain drive of this kind allows reliable power transmission to the individual conveying rollers. In addition, the toothed-belt drive, in particular, can be produced economically. 
     The shafts are expediently supported on both sides of the associated driving wheels in at least one supporting device arranged in the supporting section. In this way, reliable support for the driving wheels and the shafts that transmit the driving torque from the driving wheels to the conveying rollers is ensured. By virtue of the direct support close to the driving wheels, the transverse forces introduced into the shaft and bending moments associated with them are reduced, better and smoother running of the conveying rollers thereby being achieved overall. 
     One individual supporting device is preferably provided for a certain number of driven conveying rollers or for each individual driven conveying roller. This allows very flexible adaptation of the drive system to different numbers and arrangements of driven conveying rollers since the supporting devices can be mounted at those points in the supporting section at which driven conveying rollers are provided for the desired application. 
     The supporting device is preferably of essentially U-shaped design, the two free legs of the supporting device extending in parallel along the faces of the associated driving wheel and having the bearings for the shaft. As a result, the supporting device can be constructed in a very compact way, making it easy to arrange within a supporting section. The bearings can furthermore be arranged very close to the driving wheel, advantageous power transmission to the bearings combined with low bending moments on the shaft thereby being achieved. In this case, especially if the conveying rollers are intended only to carry light loads, the bearings are advantageously designed as simple sliding-contact bearings, in which the shaft for driving the conveying rollers is supported. 
     The supporting device is advantageously secured within the supporting section, preferably by being latched in. Corresponding grooves, in which the supporting device can be engaged by means of corresponding projections, can be provided for this purpose within the supporting section, which is preferably designed as an extruded aluminum section. This allows very rapid and economical assembly since no screwing operations or other time-consuming fastening operations involving additional fastening elements are required. 
     The supporting device can advantageously be divided in such a way that at least one of the free legs is removable. This configuration allows extremely easy fitting of the driving means, especially when this is an endless driving means such as a toothed belt. In this case, one of the free legs of the supporting device can be removed to allow the driving means to be fitted, the driving wheel and the shaft then continuing to be held by the second leg of the supporting device. The driving means, e.g. the toothed belt, can then be pushed easily onto the driving wheel, which is now accessible, and the leg removed can then be reattached to the supporting device, re-establishing support on both sides of the driving wheel. 
     The removable leg of the supporting device can preferably be connected to the remaining part of the supporting device and preferably also to the supporting section by being latched in. This further simplifies assembly since no involved assembly operations, such as screwing, are required. The parts of the supporting device are simply engaged or clipped into one another and likewise secured in the supporting section by being latched in. In this arrangement, the supporting section, which is preferably an extruded aluminum section, has corresponding latching means, e.g. corresponding latching grooves. 
     It is advantageous if the supporting device additionally forms a guide for the driving means. For this purpose, the U-shaped supporting device is dimensioned in such a way that it rests directly with its free legs against the faces of the driving wheel, the free legs thus simultaneously forming a lateral guide for a driving means passing through, e.g. a toothed belt. In addition, the distance between the circumferential surface of the driving wheel and that part of the supporting device that connects the two free legs to one another is expediently such that a guide is likewise provided in the radial direction and it is possible to prevent the driving means from slipping or jumping off the driving wheel in the radial direction. 
     The driving wheels and/or the supporting devices are advantageously manufactured from plastic. This allows extremely economical manufacture and offers a variety of design options to allow adaptation of the drive system to different applications. A certain elasticity in the supporting device can furthermore be ensured, thereby simplifying the process of engagement in the supporting section. 
     The supporting section is expediently of open construction on one longitudinal side, preferably on the longitudinal side facing away from the conveying rollers, to enable the drive arrangements to be inserted, this area of open construction preferably being closable by means of a cover strip. This allows easy access for installing and maintaining the drive system since all the elements of the drive system can be inserted laterally into the open supporting section. It is not necessary to remove the conveying rollers for this purpose since all installation, maintenance and replacement work on the drive arrangements can advantageously be carried out from the side facing away from the conveying rollers. After insertion, the area of open construction is then closed by means of the cover strip, which is preferably constructed from plastic, with the result that the entire drive system is fully encapsulated in the supporting section without the need for additional housing components to enclose the drive system securely. Moreover, this means that the drive system is reliably protected from dirt or damage and there is no danger that people will come into contact with the drive system, whereby it is possible to minimize the risk of injury. 
    
    
     The invention is described below by way of example with reference to attached drawings, in which: 
     FIG. 1 shows a sectional view of a supporting section with the drive system according to the invention, 
     FIG. 2 shows a side view of a drive arrangement according to the invention, 
     FIG. 3 shows a side view and a plan view of a first part of a supporting device, 
     FIG. 4 shows a side view and a plan view of a second part of a supporting device, and 
     FIG. 5 shows a side view and a plan view of the assembled supporting device according to the invention. 
    
    
     FIG. 1 shows a section through a supporting section  2  with a conveying roller  4  mounted on it, only the end of the conveying roller  4  that faces the supporting section  2  being illustrated. The conveying roller  4  comprises a cylindrical roller body  6  and a roller end piece  8  inserted at the end of the roller facing the supporting section  2 . The roller body  6  is preferably composed of metal, while the roller end piece  8  is preferably manufactured from plastic, e.g. by injection molding. In the direction of the longitudinal axis  10  of the roller, the roller end piece  8  has a socket  12 , into which a drive shaft  14  is inserted. The cross section of the socket  12  is that of a square, and the drive shaft  14 , which is likewise constructed as a square at its end facing the conveying roller  4 , thus enters into form-locking engagement with the socket  12 , ensuring reliable power transmission from the drive shaft  14  to the roller end piece  8  and hence to the entire conveying roller  4 . 
     The drive shaft  14  extends into the supporting section  2  through an opening  16  in the direction of the longitudinal axis  10  of the roller, starting from the roller end piece  8 . The supporting section  2  is an extruded aluminum section with, in its interior, a cavity  18 , which is open toward the longitudinal side  20  of the supporting section  2  that faces away from the conveying roller  4 . The opening of the cavity  18  toward the longitudinal side  20  extends over the entire length of the supporting section  2  in the longitudinal direction of the latter. The opening of the cavity  18  is closed by a cover strip  22 . The cover strip  22  is preferably constructed from plastic and has latching grooves  24  along its upper and lower edges, these extending over the entire longitudinal direction of the cover strip and entering into engagement with corresponding latching projections  26  on the supporting section  2 . The latching projections  26  are designed as continuous webs that extend in the longitudinal direction of the supporting section  2 . The cover strip  22  can thus be removed and refitted easily, without the need for special tools, to allow the drive arrangement to be mounted in the cavity  18 . A supporting device  28  for each driven conveying roller  4  is arranged in the cavity  18 . The supporting device  28  has an essentially U-shaped cross section with two free legs  30  and  32 , which extend parallel to the faces of a driving wheel in the form of a gearwheel  34 . The gearwheel  34  is mounted on the drive shaft  14  and the shaft thus extends completely through the gearwheel  34 . The gearwheel  34  is secured on the drive shaft  14  by means of a notched pin  36 , which extends through the drive shaft  14  essentially perpendicularly to the longitudinal axis  10  of the roller and thus fixes the gearwheel  34  on the drive shaft  14  and allows reliable power transmission from the gearwheel  34  to the drive shaft  14 . In its two free legs  30 ,  32 , the supporting device  28  has openings  38  and  40 , through which the drive shaft  14  extends and which are designed as sliding-contact bearings, in which the shaft  14  is supported. The supporting device  28  is preferably manufactured from plastic and the sliding-contact bearings in the openings  38  and  40  are thus also in the form of simple plastic shells, in which the drive shaft  14 , which is preferably manufactured from metal, is supported in a sliding manner. Extending around the opening  40  in free leg  33 , parallel to the longitudinal axis  10  of the roller, essentially perpendicularly to free leg  32  and starting from the latter, is a sleeve  42 , which has the opening  40  inside it and is configured on its outer circumference as a hexagon that engages in the opening  16  in the longitudinal side of the supporting section  2  that faces the conveying roller  4 . The opening  16  has a corresponding hexagonal form, a secure fit thus being achieved between the opening  16  and the sleeve  42 . The sleeve  42  can also have a shape different from the hexagonal outline shown here, e.g. a circular outline, the design of the opening  16  being adapted accordingly. 
     At its two corners or edges, at which the free legs  30 ,  32  are connected to the base of the U-shaped supporting device  28 , the supporting device  28  has two latching projections  44 ,  46 , which engage in associated latching grooves  48 ,  50  in the cavity  18  of the supporting section  2 . The latching grooves  48 ,  50  extend continuously in the longitudinal direction of the supporting section  2  along the two upper edges of the cavity  18  and within the latter. This allows the supporting device  28  to be snapped in at any point on the supporting section  2  at which a driven conveying roller  4  is required. All that is then required is to form a matching opening  16  at the corresponding point to enable the sleeve  42  of the supporting device  28  to engage with it. The supporting device  28  is thus connected to the supporting section  2  merely by being snapped in, thereby ensuring very easy, rapid and economical installation of the drive system. The supporting device  28  is designed in such a way that a free space for the guidance of a toothed belt  52  remains between the circumferential surface of the gearwheel  14  and the base of the supporting device  28 , which connects the free legs  30  and  32  to one another. The toothed belt  52  enters into engagement with toothing  54  on the circumference of the gearwheel  34  in order to drive the gearwheel  34  and hence, via the drive shaft  14 , the conveying roller  4 . In this arrangement, the toothed belt  52  is guided laterally between the free legs  30 ,  32  of the supporting device  28 . Since the radial distance between the supporting device  28  and the circumferential surface of the gearwheel  14  is set to match the toothed belt  52 , the belt is likewise guided on the gearwheel  34  in the radial direction by the supporting device  38 , preventing it from jumping off or slipping. 
     On its outer surface, the supporting section  2  furthermore has a plurality of fastening grooves of the kind already known from other supporting sections, by means of which the supporting section  2  can be attached to a substructure or in which slide rails or the like can be fastened. 
     FIG. 2 shows a side view of the supporting device  28 . The supporting device  28  comprises two parts  56 ,  58 , which are connected to one another, as will be described below. Each part  56 ,  58  carries one of the free legs  30 ,  32 . The gearwheel  34  is arranged between the free legs  30 ,  32  on the drive shaft  14 , which is supported in the opening  38  in free leg  30  of the supporting device  28 . Formed in the gearwheel  34  is a hole  60  (illustrated in broken lines in FIG.  2 ), which extends through the central area of the gearwheel  34  perpendicularly to the longitudinal axis of the roller and to the drive shaft  14  in order to accommodate the notched pin  36  shown in FIG. 1 for fastening the gearwheel  34  on the drive shaft  14 . On its circumferential surface, the gearwheel  34  has the toothing  54 , with which the toothed belt  52  enters into engagement on the upper side of the gear-wheel  34 . In this arrangement, the toothed belt  52  is guided between the base  62  of the supporting device  28  connecting the free legs  32  and  30  to one another and the circumferential surface of the gearwheel  34 . In this way, the toothed belt  52  can be prevented from jumping off or slipping on the gearwheel  34 . The arrangement shown in FIG. 2, with the supporting device  28 , the gearwheel  34  and the drive shaft  14 , forms the entire drive system for the conveying roller, which can be arranged variously in the supporting section  2  shown in FIG. 1 at positions at which driven conveying rollers are provided. The drive system thus forms an extremely compact unit that can be installed easily and can be arranged in a protected manner within the supporting section  2 . 
     The structure of the supporting device  28  will now be described in greater detail with reference to FIGS. 3 to  5 . FIG. 3 shows a detail view of the first part  56  of the supporting device  28 . A side view is shown at the top in FIG. 3 and a plan view is shown at the bottom in FIG.  3 . The first part  56  of the supporting device  28  contains free leg  32 , on the outside of which, i.e. the side facing the conveying roller  4  (see FIG.  1 ), the sleeve  42  is constructed with a hexagonal outline. The sleeve  42  has the opening  40 , which serves as a bearing for the drive shaft  14 . In addition, the outside of free leg  32  has formed on it reinforcing ribs  64 , which fall away obliquely and connect the outer circumference of the sleeve  42  to the outer surface of free leg  32 . The first part  56  has three tongues  66 , which extend essentially at right angles from free leg  32  and are spaced apart by two free spaces  68 . The tongues  66  start from the upper edge of free leg  32  and extend over a length that corresponds essentially to the distance between the free legs  30  and  32  in the assembled condition. The tongues  66  form part of the base  62  of the supporting device  28 . 
     FIG. 4 shows a detail view of the second part  58  of the supporting device  28 . The second part  58  is shown in side view at the top in FIG.  4  and in plan view from above at the bottom in FIG.  4 . The second part  58  carries free leg  30 , in which is formed the opening  38 , which serves as a second sliding-contact bearing for the drive shaft  14 . Extending around the opening  38 , at right angles to the outside of free leg  30 , i.e. to the side facing away from the conveying roller  4 , is a sleeve  70  (see FIG.  1 ). The sleeve  70  serves to reinforce the sliding-contact bearing, formed by the opening  38 , for the drive shaft  14 . Reinforcing ribs  72  extend obliquely downward from the sleeve  70  to the surface of free leg  30 . The second part  58  comprises two tongues  74 , which extend essentially perpendicularly from free leg  30 . The tongues  74  start from the upper edge of free leg  30  and extend over a length that corresponds essentially to the distance between the two free legs  30 ,  32 . The two tongues  74  extend parallel to one another and are spaced apart, a free space  76  thus being formed between the two tongues  74 . The width of the free space  76  corresponds to the width of the central tongue  66  in FIG.  3 . The width of the tongues  74  in each case corresponds to the width of the free spaces  68  in FIG.  3 . 
     FIG. 5 shows how the first and second parts  56 ,  58  of the supporting device  28  that are shown in FIGS. 3 and 4 are assembled. The overall supporting device  28  is shown in section at the top in FIG.  5 . The two free legs  30 ,  32  are connected to one another by the base  62 , giving the overall supporting device an essentially U-shaped form. The sleeve  42  with the opening  40  formed therein, which has been described above, is provided on free leg  32 . Free leg  30  has the opening  38  described above. The two corners or edges at the transition from the base  62  to the free legs  30 ,  32  are designed as latching projections  44 ,  46 , as described with reference to FIG.  1 . The overall supporting device  28  is of two-part design, being made up of the first and second parts  56 ,  58 , which are illustrated on the right and the left in FIG.  5  and have been described in greater detail with reference to FIGS. 3 and 4. The two parts  56 ,  58  are inserted one into the other in such a way that the tongues  74  of part  58  come to rest in the free spaces  68  between the tongues  66  of part  56 . The front ends of the tongues  74 , i.e. the ends spaced apart from free leg  30 , are designed in such a way as to correspond to the latching projection  46 . The rear ends of the tongues  66  of part  56 , i.e. the ends facing leg  32 , are likewise designed in a manner corresponding to the latching projection  46 . In the assembled condition of parts  56  and  58 , tongues  74  and tongues  66  thus together form the continuous latching projection  46  in the form of a continuous edge. Conversely, the free ends of the tongues  66 , i.e. the sides facing away from free leg  32 , are likewise designed to correspond to the latching projection  44 , with the result that, in the assembled condition of parts  56  and  58 , they form a continuous latching projection  44  along the edge of the base  62  together with the rear ends of the tongues  74 , i.e. the ends facing leg  30 , which are likewise designed to correspond to the latching projection  44 . 
     The assembly of the drive arrangement according to the invention will now be described, once again with reference to FIG.  1 . The gearwheel  34  is first of all connected to the shaft  14  and secured on the latter by means of the notched pin  36 . The gearwheel  36  is then pushed into the opening  40  in leg  32  of part  56  (see FIG. 3) of the supporting device  28  with the shaft  14 . Part  56  is then inserted into the cavity  18  within the supporting section  2 . During this process, the sleeve  42  is fitted into the opening  16  and the latching projections  44  and  46  on the tongues  66  (see FIGS. 3 and 5) engage in the latching grooves  48  and  50  in the supporting section  2 . The driving wheel and part  56  of the supporting device  28  are thus held securely in the cavity  18  within the supporting section  2 . The toothed belt  52  can then be introduced into the cavity  18  through the open longitudinal side  20  of the supporting section  2 . During this process, the toothed belt  52  is pushed onto the upper side of the gearwheel  34 , with the result that it comes to rest between the base  62  (see FIGS. 2 and 5) of the supporting device  28  and the toothing  54  of the gearwheel  34 , entering into engagement with the toothing  54 . The second part  58  of the supporting device  28  is then pushed onto the first part  56  of the supporting device  28  by means of the leg  30 , as explained with reference to FIG.  5 . During this process, the opposite end of the shaft  14  from the conveying roller  4  enters the opening  38  in leg  30 . At the same time, the second part  58  engages in the latching grooves  48  and  50  of the supporting section  2  by means of those parts of the latching projections  44  and  46  that are formed on the tongues  74 , with the result that the second part  58  of the supporting device  28  too is held securely within the supporting section  2 . As a departure from this embodiment, in which the second part  58  of the supporting device  28  also engages in the supporting section  2 , the second part  58  can also be configured in such a way that it engages only with the first part  56  of the supporting device  28 , which is in engagement with the supporting section  2 . In this way, even simpler assembly is achieved since the second part  58  has only to be connected directly to one other component. 
     The cover strip  22  can then be engaged on the latching projections  26 , with the result that the cavity  18  in the supporting section  2  is completely closed off from the outside, preventing any dirt from entering the cavity  18  and ensuring that there is no risk of injury to persons working close to the roller conveyor. The supporting section  2  is then mounted on a roller conveyor together with an opposite supporting section (not shown here) in order to accommodate conveying rollers  4 . The conveying roller  4  is then mounted by means of the recess  12  in its roller end piece  8  on the square free end of the drive shaft  14  and mounted in a known, rotatably supported, manner on the other supporting section (not shown) at its other end. The result is that the drive arrangement according to invention can be mounted in the supporting section  2  in an extremely simple manner that does not require any screwing operations or other complicated assembly operations. In addition, the entire drive arrangement comprising the supporting device  28 , the gearwheel  34  and the toothed belt  52  is fully enclosed hin the supporting section  2 . 
     LIST OF REFERENCE NUMERALS 
       2  Supporting section 
       4  conveying roller 
       6  roller body 
       8  roller end piece 
       10  longitudinal axis of roller 
       12  recess 
       14  drive shaft 
       16  opening 
       18  cavity 
       20  longitudinal side 
       22  cover strip 
       24  latching groove 
       26  latching projection 
       28  supporting device 
       30 ,  32  free leg of the supporting device 
       34  gearwheel 
       36  notched pin 
       38  opening 
       40  opening 
       42  sleeve 
       44 ,  46  latching projections 
       48 ,  50  latching grooves 
       52  toothed belt 
       54  toothing 
       56  first part of the supporting device 
       58  second part of the supporting device 
       60  hole 
       62  base 
       64  reinforcing ribs 
       66  tongues 
       68  free space 
       70  sleeve 
       72  reinforcing ribs 
       74  tongues 
       76  free space