Abstract:
The grinder has a frame (6) movable on rollers (8) on which is fitted a grinding device (18) drivable by a motor (84). In order to simplify the grinder and its application to a roll (4) to be treated, the rollers (8) are designed to lower the frame (6) on a scraper (10) or on a rail (56) of a scraper device (2) associated with the roll (4), which rail replaces the scraper (10). The frame (6) has a supporting roller (14) fitted on an adjustable holder (12) which is laterally supported on a bearer (16) for the scraper (10).

Description:
FIELD OF THE INVENTION 
     The invention concerns a grinder for grinding a cylindrical or spherical surface of a roll, especially the roll of a paper machine, the roll being one having a scraper device associated with it. 
     BACKGROUND OF THE INVENTION 
     A grinder of the above-mentioned kind is for example known from CH-PS 668 212. This device is relatively complicated and accordingly its provision very expensive, since a special carrier as well as an adjustable copying pattern corresponding to the desired shape of the surface to be worked, and which forms a guide path, are required. 
     The object of the invention is to provide a grinder of the above-mentioned kind adapted to be brought into temporary association with a roll when needed for refinishing the surface of the roll, and which has a simple construction and is easy to use. 
     SUMMARY OF THE INVENTION 
     The invention resides in that the grinder uses the scraper apparatus associated with a roll as a carrier and, if need be, as a copying pattern. The additional provision of a carrier and, as the case may be, a copying pattern is therefore unnecessary. The grinder is accordingly simple and inexpensive to make and can moreover be quickly and simply put into place. These advantages especially arise if a damaged roll must be refinished. 
     The rapid and simple provision capabilities of the grinder thereby also reduces the downtime of a production line. The invention further resides in the grinder being one including a belt grinding mechanism with a contact roll over which the belt passes with the contact roll being floatingly supported so as to be able to suit the contour of the outer surface of the roll so that, for example, cambered rolls can also be ground; and in an alignment apparatus which prevents a tilted application of the grinding member to the roll and thereby avoids fault constituting grinding marks. The invention also resides in further details of the grinder described in the following description and claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the subject matter of the invention are described in more detail hereinafter in connection with schematic drawings which show: 
     FIG. 1 is a side view, in the direction of sliding movement, of a belt grinder applied to a roll. 
     FIG. 2 is a top view of the belt grinder of FIG. 1. 
     FIG. 3 is a sectional view of the frame of the belt grinder taken along the line III--III of FIG. 4. 
     FIG. 4 is a sectional view of the frame of the belt grinder taken along the line IV--IV of FIG. 3. 
     FIG. 5 is a sectional view of the frame of the belt grinder with a supplemental securing apparatus taken along the line V--V of FIG. 6. 
     FIG. 6 is a right side view of the securing apparatus of FIG. 5. 
     FIG. 7 is a horizontal sectional view of the belt grinder of FIG. 1. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 and 2 are complete views of a grinder embodying the invention and which grinder is adapted to be temporarily mounted on the scraper apparatus 2 associated with a roll 4, for example the roll of a paper machine, for the purpose of grinding the surface of the roll to improve its condition. The grinder includes a frame 6 with rollers 8 which is placed on a scraper blade 10 of the scraping apparatus 2, the scraping apparatus 2 being shown in the condition of being pivoted away from the roll 4. A frame 6 includes a holder 12 with an engagement roller 14, which laterally engages the carrier 16 of the scraping apparatus 2. A grinder mechanism 18, in the form of a belt grinder mechanism, is fastened to the frame 6. 
     The holder 12 has an upper arm 20 and a lower arm 22 which are fastened to the frame 6 and extend transversely to the plane of the rollers 8. Each arm 20, 22 is provided with a double clamping member 24 which itself is fixed to the associated arm 20, 22 by means of a clamping screw 26. A rod 28 is fixed to the clamping members so as to extend transversely to the arms and likewise is fixed by clamping screws 30. The engagement roller 14 is supported on the lower end of the rod with the plane of the roller 14 running perpendicular to the plane of the rollers 8. With the help of the clamping members 24 the rod 28 can be adjusted as to its position on the arms 20, 22 as well as to its height. The arrangement of the holder 12 is such that the rod 28 is located along the length of the frame 6 halfway between the rollers 8. Thereby a three point support is achieved which is especially stable. Moreover this support makes it possible that the grinder mechanism 18 can be exchangably fastened at the cheeks 32, 34 of the frame 6. For this the grinder mechanism 18 is made so as to be essentially mirror image symmetrical with respect to the horizontal plane 36, so that through use of the mounting plate 38 forming part of the grinder mechanism the grinder mechanism can be selectively attached to either one of the two cheeks 32, 34. 
     FIGS. 3 and 4 show details of the drive of the rollers 8 of the frame 6. As to this, the frame contains a drive motor 40 which through a drive 42 and a clutch 44 drives a drive wheel 46 for a toothed belt 48. The belt 48 is trained over two wheels 50, fastened to shafts 52, on which the rollers 8 are arranged. 
     FIGS. 5 and 6 show a supplementary securing mechanism 54 for securing the grinder to the scraper apparatus 2. In this case the scraper 10 of the scraper apparatus 2 is first replaced in the scraper apparatus 2 by an L shaped rail 56. The rollers 8 run on the rail 56. The securing mechanism 54 includes securing rollers 58 which are associated with the rollers 8 and which are pivotal into engagement with the inner side 60 of the L shaped rail 56. For this the securing rollers 58 are fastened to a pivot axle 62 which in turn is pivotably supported in arms 64 on the frame 6. To the pivot axle 62 is fastened a lever 66 which is connected through a coupling member 68 with a threaded spindle 70. The spindle 70 cooperates with a rotatably supported sleeve 72 having a non-illustrated internal thread. The sleeve 72, which is rotatably supported in the frame 6, is provided with a hand crank 74. By rotation of the hand crank 74 the securing rollers 58 can be moved into and out of engagement with the inner side 60 of the L shaped rail 56 as well as be pressed against it. 
     FIGS. 1, 2 and 7 show the grinding mechanism, formed as a belt grinding mechanism 18, in detail. The grinding belt 76 is guided over a floatingly supported contact roll 78, over fixedly positioned guide rolls 80, 82 adjacent both sides of the contact roll, and over a drive roll 86 driven by a drive motor 84. The drive motor 84 is arranged on a slide 88 which is arranged in a housing 92 containing the floating support 90 for the contact roll 78. A belt tensioning device 94 serves to tension the grinding belt, which device cooperates with the slide 88 of the drive motor 84 and biases the drive roll 86 away from the contact roll 78. The belt tensioning device 94 includes a piston/cylinder unit 96 connected by conductors 98, 100 with a fluid mechanism 102. The floating support 90 for the contact roll 78 includes longitudinal guides 104, 106 contained in the housing 92 for the axle 108 on which the contact roll 78 is rotatably supported. The longitudinal guides 104, 106 extend perpendicularly to the surface to be worked, that is radially to the work roll 4. The axle 108 in the longitudinal guides 104, 106 is yieldingly engaged with piston/cylinder units 110, 112. In connection with this, the corresponding pressure spaces of the piston/cylinder units 110, 112 are connected with one another by Connecting conductors 114, 116. The piston/cylinder units 110, 112 are moreover connected by conductors 118, 120 to the fluid apparatus 102. The piston/cylinder units 110, 112 also serve at the same time for positioning the contact roll against the work surface, that is the work roll 4. An alignment device 122 serves for aligning the contact roll in the delivery and application of the contact roll 78 to the work surface in order to avoid a one-sided contact and therewith a one-sided grinding of the roll 4. The alignment device 22 includes threaded shafts 124 on both sides of the contact roll 78, of which only one shaft is illustrated, with a rigidly locked contact surface 26, which is displaced rearwardly a few tenth millimeters from the working position of the grinding belt. Each threaded shaft 124 is fastened to a protective cover 128 for the floating support 90, which cover itself is connected with the axle 108 of the contact roll 78. If the contact roll 78 is unequally delivered, one of the two threaded shafts 124 come to rest on the roll 4 and brings the contact roll into essentially aligned position with the roll. 
     The control for the grinding mechanism through the fluid apparatus 102, which is preferably an air pressure apparatus, takes place in a way, not more specifically illustrated, such that first through the piston/cylinder unit 96 the grinding belt 76 has imparted to it a given tension force. In connection with this the contact roll 78 through the axle 108 engages the associated piston/cylinder units 110, 112 in which the necessary counterpressure is built up. If the contact roll 78 is pushed forwardly against the work surface, that is against the roll 4, with the help of the piston/cylinder units 110, 112, the piston/cylinder unit 96 is retracted to the same measure, so that the once adjusted belt tension remains constant. Upon grinding the guide rolls 80, 82 serve for the stabilization of the grinding belt on the contact roll 78, especially when because of the contour of the work surface the contact roll 78 because of the floating support 90 takes on an angular position deviating from its base position. Because of the floating support 90 the contact roll 78 can follow the contour of a surface to be ground. Thereby it is possible, without special measures to re-grind an existing surface especially to improve it. The fluid apparatus 12 provides that during straight line guiding of the belt grinding mechanism, the pressure at which the contact roll is applied to the work surface, and which contact roll may for example be following a cambered contour of the work surface, is always held constant.