Abstract:
A length-variable sliding rail element enables a roller chain to be easily guided. Two complementary sliding rail elements fit together. Each of the sliding elements may be comprised of two or three segments. These various segments interengage each other to form a sliding rail element that is shiftable between collapsed and extended position.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a length-variable guide rail element for a roller chain. The guide rail element is formed by two partial elements which can be displaced relative to each other and which have complementarily meshing segments. 
     DESCRIPTION OF THE PRIOR ART 
     A length-variable guide rail element, embodied C-shaped in profile, for use with a roller chain, in particular for a draw-in device, is known from DE 44 11 493 C1. The guide rail element consists of two partial guide rail elements, which can be pulled apart and which each have two diagonally opposite segments. 
     DE 42 02 713 C2 discloses a guide rail element having three segments, at one end of which, respectively viewed in cross section, a first segment is located opposite a second and third element on the other side of the roller. This guide rail element as a whole consists of five segments. 
     GB 2 125 758 A describes a section for a conveying device, which can be drawn apart. Here, two decks are arranged one above the other, wherein the respective lower running surface can be extended by means of a bracket. 
     GB 892 208 A describes a chain conveyor, wherein the chain links are length-variable and spatially movable. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is based on providing a length-variable guide rail element. 
     In accordance with the present invention, is object is attained by providing a length variable guide rail element which has two partial elements. These two partial elements can be displaced relative to each other and have opposing segments. These segments are complementary in shape and mesh with each other. The two partial elements can be placed adjacent each other in a first position and can be drawn apart to a second position. 
     The advantages which can be obtained by means of the present invention rest, in particular, that a length-variable guide rail element is provided, which guides portions of a roller chain without problems. Thus, in a first preferred embodiment of a guide rail element, a roller chain can also be guided in an interlocked manner. Such a length-variable guided rail element can be used, for example, with a device, arranged on a lateral frame, for drawing in webs of material into web-fed rotary printing presses. 
     A length-variable guide rail element in accordance with a second preferred embodiment of the present invention also assures the problem-free guidance of a roller chain. This guide rail element is particularly suited for draw-in devices for wide webs of material, for example in connection with web-fed rotary rotogravure printing presses, wherein a roller chain is simultaneously guided in each of the two lateral frames, which are connected by means of struts over the clear width of the press. Length-variable guide rail elements can be employed in the same way in sheet-fed rotary printing presses, which respectively guide an endless roller chain for a so-called gripper carriage. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Two preferred embodiments of the present invention are represented in the drawings and will be described in greater detail in what follows. Shown are in: 
     FIG. 1, a perspective representation of a length-variable guide rail element in accordance with a first preferred embodiment of the present invention; 
     FIG. 2, a cross section taken along line II—II of FIG. 1, but with a representation of a cross section of a roller chain, 
     FIG. 3, a perspective representation of a length-variable guide rail element in accordance with a second preferred embodiment of the present invention; and in 
     FIG. 4, a cross section taken along line IV—IV of FIG. 3, but also with a representation of a cross section of a roller chain. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A first preferred embodiment of a length-variable guide rail element  1  has a C-profile in cross section for receiving a roller chain  2 , and consists of two separate partial guide rail elements  3 ,  4 , each of which has three segments  6 ,  7 ,  8 ; and  9 ,  10 ,  11 , respectively which are located opposite each other and which mesh in a complementary manner, all as may be seen in FIGS. 1 and 2. 
     Of the three segments  6 ,  7 ,  8 , of the first partial guide rail element  3  or respectively the three segments  9 ,  10 ,  11 , of the second partial guide rail element  4  a respectively first or tongue segment  6 ,  9  is located opposite a second or finger segment  7 , and a third or body segment  8 , or respectively  11 , which finger and body segments  7 ,  8  or  10 ,  11  are respectively located on the other side of the roller  14  of roller chain  2  with respect to the tongue segment  6  or  9  of the partial guide rail element  3 ,  4 . 
     The segments  6 ,  7 ,  8 , or respectively  9 ,  10 ,  11 , of the partial guide rail elements  3 ,  4  are alike, if each of their cross sections is turned by 180° around an axis of rotation  13  of the rollers  14  of the roller chain  2 , as may be seen most clearly in FIG.  2 . 
     If the rollers  14  of the roller chain  2  are guided, for example, in a channel in the guide rail element  1  and bordered by four planes A, B, C, D, which intersect each other at right angles, of which respectively two planes A, B, as well as two planes C, D, extend parallel with each other, and at least two planes A, B extend parallel, in respect to the axis of rotation  13  of the roller  14 , the first or tongue segment  6  of the first partial guide rail element  3  rests against the first upper level A. Furthermore, the second or finger segment  7  of the first partial guide rail element  3  rests against the third, left, vertically extending plane C, and the third or body segment  8  rests against the fourth, right, vertically extending plane D. The second and third segments  7  and  8  also rest against or define the second, lower plane B. 
     The three segments  9  to  11  of the second partial guide rail element  4  rest against the roller  14  as follows: the first or tongue segment  9  rests against the second, horizontal lower plane B, the second segment  10  rests against the third, left, vertically extending plane C, the third segment  11  rests against the fourth, right, vertically extending plane D, the second and third segments  10  and  11  rest against the first upper horizontal plane A. 
     In the second, or drawn-apart position of the first embodiment of the length variable guide rail element, as seen in FIG. 1, the rollers  14  are guided either by the segments  6  to  8  of the first partial guide rail element  3 , or by the segments  9  to  11  of the second partial guide rail element  4 . Depending on the load on the roller chain  2 , a running surface for the roller  14  can be located either in the plane B or in the plane A, or partially in both planes B, A. 
     The rollers  14  are connected with each other by means of inner or outer brackets  18 ,  19 , or  21 ,  22 , and chain bolts  23 . 
     If a chain guide must be designed to be length-variable, a partial chain guide element  3  or  4  is fixed on the lateral frame. In that case, both partial chain guide elements  3  and  4  are advantageously arranged, fixed in place on the lateral frame, in a preselected drawn-apart state if, for example, large temperature variations have an effect on the length of the chain guide, for example in drying ovens. 
     However, it is also possible to seat, i.e. to fasten, both partial chain guide elements  3 ,  4  at least slidingly in the lateral frame. 
     In accordance with a second preferred embodiment of the subject invention as shown in FIGS. 3 and 4, a guide rail element  27  consisting of two partial guide rail elements  24 ,  26 , has a total of five segments  28  to  32 . The first partial guide rail element  24  provides two segments  28 ,  29 , and the second partial guide rail element  26  supports three segments  30 ,  31 ,  32 , which five segments mesh in a complementary manner. 
     Viewed in cross section, as seen in FIG. 4, the two segments  28 ,  29  of the first partial guide rail element  24  are arranged above and below the roller  14 , so that the first or upper body segment  28  rests against the first upper plane A and the second or lower body segment  29  against the second, lower plane B, and both segments  28 ,  29  together rest against the fourth, or right, vertical plane D. 
     Viewed in cross section, as seen in FIG. 4, the three segments  30 ,  31 ,  32  of the second partial guide rail element  26  are arranged in such a way that the first or upper finger segment  30  is arranged above and the second or lower finger segment  31  below the roller  14 , and the third or intermediate finger segment  32  is arranged in the direction of the axis of rotation  13  of the rollers  14 , next to the roller  14 , as well as between the first and second or upper and lower body segments  28 ,  29  of the first partial, element  24 . In this case, the first or upper finger segment  30  of the second partial guide rail element  26  rests against the first upper plane A, and the second or lower finger segment  31  against the second, lower plane B, and both segments  30 ,  31  rest together against the third, left, vertically extending plane C. The third or intermediate finger segment  32  of the second partial guide rail element is arranged complementary between the two segments  28 ,  29  of the first partial guide rail element. 
     Different chain bolts  23  of a roller chain  2  running in a first lateral frame can be connected by means of struts  34  as seen in FIG. 4 with similarly seated chain bolts of a second roller chain running in a second lateral frame, which is not specifically shown. 
     By means of this structure of chain bolts and struts it is possible to form a gripper carriage for sheet-fed rotary printing presses, or in case of web-fed rotary printing presses, to form a carriage extending over the entire width of the press for drawing in a particularly wide material web. 
     The first and second partial guide rail elements  24 ,  26  in accordance with the second preferred embodiment, as depicted in FIGS. 3 and 4, can be designed in such a modified way that the first or upper body segment  28  of the first partial guide rail element  24 , as well as the first or upper finger segment  30  of the second partial guide rail element  26 , each are of a greater length than the segments  29 ,  31 ,  32 . 
     Alternatively to this, the segments  29 ,  31  of the first and second partial guide rail elements  24 ,  26  can have a different, for example greater length in respect to the the segments  28 ,  30 ,  32 . Because of this, gaps  36 ,  37  are created in the second, drawn-apart position of the two partial elements  24 ,  26 , which gaps are not located above each other, as represented in FIG. 3 but instead may be next to each other in an arrangement not represented in FIG.  4 . 
     While preferred embodiments of a length-variable sliding rail element for a roller chain in accordance with the present invention, have been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that a number of changes in, for example, the specific type of printing press being used with the rail elements, the drive for the roller chain, and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the appended claims.