Method of drilling of holes into the mantle of a cylinder in a paper machine and equipment for use in the method

Abstract: The invention concerns a method for drilling of holes into the mantle of a cylinder in a paper machine while the cylinder is in its place of operation in the paper machine. In the method, after each cycle of drilling, a multi-spindle drilling machine (10) is transferred along guide rails (12a,12b). In the method, the guide rails (12a, 12b) are supported against the cylinder (S₂) adjacent to the cylinder (S₁) to be machined, whereby, in the method, before the drilling is started, the drill equipment (11) is tensioned between the mantle face of the cylinder (S₁) to be machined and the mantle face of the adjacent cylinder. The invention also concerns equipment for use in the method.

Description: The invention concerns a method and a device for perforation of the mantle of a cylinder in a paper machine, in particular of the mantle of a drying cylinder, on the site without detaching the cylinder from its place of operation. In operations of modification of the cylinders in a drying group in a paper machine, the drying cylinder has been removed from its place and carried aside for machining. At present, ordinary non-perforated cylinders in a drying group are converted to so-called UNO-VAC (registered trademark) cylinders by perforating the cylinder mantle. In prior art, said perforation had to be carried out at a separate machining point either at the paper mill or in a workshop specialized in conditioning of cylinders. The document EP-A-0 262 756 shows a multi-spindle drilling machine which is provided for clearing holes in tubular members, in particular in a suction roll in a paper machine. The operation of this drilling machine can be performed when the suction roll is in its operating location in the paper machine and comprises a basic frame being movably supported on guides by means of rollers, a spindle box with a number of drill bits disposed therein which are fitted to be rotated by a drive motor, said spindle box being connected to said basic frame and being movable in a direction toward said mantle of said roll to be machined. However, when operating the drilling machine, vibrations occur which impair the operation and deterioriate the quality of this work. Therefore, it is the object of the present invention to provide a method for a multi-spindle drilling machine being able to perform the drilling operation in a stable manner and whose assembly and accurate positioning can be done efficiently. This object is achieved by the features of claims 1 and 6. In the method of the present invention, it has been realized to provide an arrangement wherein the drilling machine moves on support of separate guides in the axial direction of the roll, said drilling unit being fitted to be supported, during the machining process, both on the mantle face of the cylinder that is being machined and on the mantle face of the adjacent cylinder. The equipment comprises a spindle box of a multi-spindle drilling machine, which box contains a unit of rotation for the drill bits and related power transmission means for simultaneous transfer of the rotation to all of the drill bits placed side by side. The equipment further comprises a cylinder, by whose means the jig of the drill bits, i.e. the drill guide, is controlled into contact with the face to be machined, whereby, as the equipment is supported both on the cylinder that is being machined and on the adjacent other cylinder constituting a support base for the guides, for the time of the machining a unified robust structure is formed to permit undisturbed drilling. The equipment in accordance with the invention comprises a spindle box displaceable in relation to the main frame and therein a separate motor for displacing of the spindle box with its drills. Further, the equipment comprises a motor for the rotation of the drill bits. The method in accordance with the invention is mainly characterized in that in the method, after each cycle of drilling, the multi-spindle drilling machine is transferred along guide rails and that in the method the guide rails are supported against the cylinder adjacent to the cylinder to be machined, whereby, in the method, before the drilling is started, the drill equipment is tensioned between the mantle face of the cylinder to be machined and the mantle face of the adjacent cylinder by displacing the drill guide into contact with the cylinder face to be machined. The device in accordance with the invention is mainly characterized in that the equipment comprises a spindle box and therein a number of drill bits, which are fitted to be rotated by a drive motor, and that the spindle box comprises a drive motor, which is fitted to displace the spindle box relative the basic frame of the drill equipment when the drill bits are passed towards the cylinder face to be machined, and that the equipment comprises a drill guide, by whose means the drill equipment can be supported and tensioned between the guides and the mantle face of the cylinder to be machined, whereby the machining process becomes free from vibrations, and that the equipment comprises slide bushings or equivalent, which guide the basic frame of the drill device in a guide when the equipment is being transferred in the direction of the longitudinal axis of the cylinder as the equipment is being shifted to the following drilling position. The invention will be described in the following with reference to some preferred embodiments of the invention illustrated in the figures in the accompanying drawings, the invention being, however, not supposed to be confined to said embodiments alone. Figure 1 is an axonometric illustration of a preferred embodiment of the method and the device in accordance with the invention. Figure 2 is a schematic illustration of the main components of the device in accordance with the invention. Figure 3A is a schematic illustration of the equipment of rotation of the drill bits placed side by side. Figure 3B is a sectional view taken along the line I-I in Fig. 3A. Figures 4A...4D illustrate the arrangement of equipment employed for displacing the spindle box and the drill guide. Figure 5 illustrates the support of the basic frame of the device on two guide bars. Fig. 1 is an axonometric view of a preferred embodiment of the device in accordance with the invention in its machining location between two adjacent cylinders S₁ and S₂ of a paper machine. The equipment 10 comprises a basic frame 11, which is supported on guides 12 supported and fixed on the cylinder S₂ on the cylinder mantle. The guides 12a and 12b are connected with the frame part 14, which is further supported on the face of the cylinder S₂ by means of fastening belts 13 (one belt is shown in the figure). The belts 13 are passed around the cylinder. The guides 12a and 12b pass in the axial direction of the cylinder over the width of the mantle of the cylinder. The basic frame 11 of the drilling equipment 10 comprises slide bushings 15, on whose support the basic frame 11 is displaced in the axial direction of the cylinder manually after each drilling cycle. The drilling equipment 10 in accordance with the invention comprises a spindle box 16, to which the motor 18 of rotation of the drill bits 17 is attached. In the embodiment shown in Fig. 1, the motor 18 of rotation is fitted to rotate twelve drill bits 17 placed side by side in a row at the same time. The spindle box further comprises a motor 20 attached to the box, by means of which motor the spindle box 16 and the drill bits 17 placed in it are displaced so as to produce the feed movement of the drill bits 17 and to move the drill bits apart from the roll mantle to be drilled after the drilling. Before the drilling is started, the drill guide 19 is brought into contact with the mantle face to be machined by displacing the drill guide 19 by means of its actuator 21, preferably a cylinder device, into contact with the cylinder face. Thus, for the time of the drilling, the drill equipment 10 is supported both on the cylinder S₁ to be machined and on the adjacent cylinder S₂. Thus, when the drill guide 19 is tensioned against the face to be machined by means of the actuator 21, the overall construction becomes rigid. Precise drilling can be accomplished as the vibrations during the machining are minimized. In Fig. 1, the reference numeral 22 denotes the equipment of rotation of the cylinder to be machined. The equipment 22 of rotation comprises a cogwheel 24 and a lever 25 of rotation connected to the axle of the cylinder S₁. On completion of its working stroke, the lifting cylinder 23 shifts the lever 25 upwards and rotates the cylinder S₁ to be machined to the next working step after the preceding row has been drilled. The movement of rotation corresponds to one tooth gap, and the cylinder is locked by means of a locking cylinder 26,27 in a fixed position for the time of the machining. Fig. 2 is a schematic illustration of the main components of the drilling equipment 10 in accordance with the invention. The drill equipment 10 comprises a basic frame 11. The basic frame 11 is supported on the guides 12 by means of slide bushings 15 connected to the basic frame 11. The guides 12 are connected to the frame part 14, which frame part 14 is attached by means of a fastening belt 13 to the cylinder adjacent to the cylinder to be machined. The spindle box 16 is displaced in relation to the basic frame 11 by means of a motor 20 of displacement of the spindle box. The spindle box 16 comprises a number of drill bits 17 placed side by side, said drill bits being rotated by means of a rotation motor 18. The motors 18 and 20 of rotation are placed in fixed positions in the spindle box 16. The drill guide 19 is displaced in relation to the spindle box 16 as guided by separate guide shafts 28, and the displacing of the drill guide 19 is produced by means of an actuator 21, preferably a cylinder device placed inside the spindle box 16. By operating the cylinder device 21, the drill guide 19 is displaced into contact with the roll mantle to be machined while the guide shafts 28 glide in the guide bushings 29b in the ends of the guide shafts 29 of the spindle box 16. The drilling process is as follows. The drill equipment 10 is fixed to the cylinder S₂ adjacent to the cylinder S₁ to be machined by means of fastening belts 13 (in the figure, one belt 13 is shown). The equipment 10 is displaced (arrow L₁) into the drilling position along the guides 12. By means of the cylinder device 21, the jig, i.e. the drill guide 19, is displaced into contact with the face of the cylinder to be machined (arrow L₂). The spindle box 16 with the drill bits 17 is displaced by means of the motor 20 towards the cylinder S₁ to be machined (arrow L₃). The spindle box 16 is guided by the shafts 29. The rotation of the drill bits 17 is switched on, i.e. the motor 18 is switched on. Upon completion of drilling, the sequence of operations is reversed, and the drill equipment 10 is shifted to a new drilling position along the guides 12, being guided by the slide bushings 15. Fig. 3A shows the rotation drive of the drill bits. What is shown is merely the spindle box with the drill guide removed. From the output shaft of the rotation motor 18,: the rotation is transferred by means of a belt transmission H to the set of drive wheels of the drill bits in the spindle box, first to the first driven shaft, from whose cogwheel the rotation is distributed further to the drill bits 17. Fig. 3B is a sectional view taken along the line I-I in Fig. 3A. In Fig. 3A, further, the arrangement of displacement of the spindle box 16 in accordance with the invention is shown. The motor 20 of displacement of the spindle box 16 rotates a cogged belt 30. The cogged belt is passed over four separate belt pulleys 31, and each pulley 31 for the cogged belt is journalled to revolve on bearing means 34 in relation to the spindle box 16. Figs. 4A...4C are more detailed illustrations of the arrangement of displacement of the drill guide 19 in the spindle box 16. Fig. 4A shows the frame construction of the whole device as viewed from the front. Fig. 4B is a partial sectional view of the solution of equipment. The drill guide and the guide of the spindle box are shown. Fig. 4C is an illustration of principle of the ballnut drive of the spindle box. Fig. 4D is a more detailed illustration of the solution shown in Fig. 4C. Fig. 4A is a front view of the frame construction of the drill device. In Fig. 4B, the construction of Fig. 4A is shown as a side view and partly in section. The frame 11 is guided on support of the bushings 15 in guides, which are further attached to the cylinder adjacent to the cylinder to be machined. From Fig. 3A it comes out that the spindle box comprises cogged-belt pulleys 31 in the four corners of the box 16, the cogged belt 30 being passed over said pulleys. The motor 20 operates the cogged belt and thereby the cogged-belt pulleys 31. Also, in the solution of Fig. 4B, the actuator 21 is shown by whose means the drill guide 19 is displaced into the position indicated by the dasheddotted line in Fig. 4B. Fig. 4C is a more detailed illustration of the displacing of the spindle box and of the arrangement of displacing of the drill guide. Each cogged-belt pulley 31 comprises an inside ball nut 32. Thus, by means of the cogged belt 30, the cogged-belt pulleys 31 and the related ball nuts 32 are rotated. Through the ball nut 32, a ball screw 33 has been passed, which has been made onto the guide shaft 29 and which is jointly operative with the ball nut. The ball screw 33 is attached permanently to the basic frame 11. The ball nut 32 is journalled on the spindle box 16 by means of bearings 34. Thus, when the motor 20 for displacement of the spindle box 16 is rotated, the cogged belt 30 is operated and, further, the cogged-belt pulleys 31 are rotated and the spindle box 16 and the related means, such as the drill bits 17, are displaced in the way shown by the arrow L₃ towards the cylinder to be machined. Before the drilling is started, the drill guide 19 has been displaced by means of the actuator 22 into contact with the cylinder face to be machined. The drill guide 19 is shifted on support of the guide shafts 28, being guided by the guide bushing 29b of the guide shaft 29 of the spindle box 16, into an accurate position in relation to the cylinder to be machined. Upon completion of the drilling, the sense of rotation of the motor 20 for displacement of the spindle box is reversed and the spindle box 16 with the related drill bits 17 is shifted out of contact with the cylinder to be machined. Fig. 4D is a still more detailed illustration of the solution of Fig. 4C in respect of the system of displacement of the spindle box 16 and of the guide shaft 28 of the drill guide. The cogged belt 30 is passed over the cogged-belt pulley 31. The ball nut 32 is attached to the cogged-belt pulley, which nut 32 is further jointly operative with the ball screw 33 on the spindle-box guide shaft 29. The ball nut 32 is journalled to revolve in relation to the spindle box 16 on the bearings 34 (shown in Fig. 4C). The guide shaft 28 of the drill guide 19 glides in the guide bushing 29b fitted in the hollow end space in the shaft 29. When the belt 30 is operated, the nut 32 is rotated and thereby the spindle box 16, which is mounted in a fixed position in relation to the nut, is displaced in the direction determined by the operation of the belt 30, either towards the cylinder to be machined or away from said cylinder. Fig. 5 shows the attaching of the drill equipment 11 on the cylinder S₂ on support of the guides 12a and 12b fitted on the cylinder S₂.

Claims: Method for drilling holes into the mantle of a first cylinder (S₁) in a paper machine which is provided with at least a second cylinder (S₂) adjacent to said first cylinder (S₁), while the cylinders are in their place of operation in the paper machine, comprising the following steps: fastening guides (12) to said second cylinder (S₂) in the direction of the longitudinal axis thereof by means of belts (13) or equivalent, supporting a frame (11) comprising a spindle box (16) with a number of drill bits (17) which are fitted to be rotated by a first drive motor (18) onto said guides (12) by means of slide bushings (15) or equivalent, said spindle box (16) being movable relative to said frame (11) in a direction towards the mantle of said first cylinder (S₁) by means of a second drive motor (20), transferring said frame (11) along said guides (12) in an operating position, tensioning said frame (11) between the mantle of the first cylinder (S₁) and the mantle of the second cylinder (S₂) by moving a drill guide (19) which is movably supported on said frame (11) in direction towards the mantle of said first cylinder (S₁) and disposed on the opposite side of said spindle box (16) with respect to said guides (12) in a position facing the mantle of said first cylinder (S₁), into contact with the mantle of said first cylinder (S₁), and drilling a number of holes into the mantle of said first cylinder (S₁) by moving said spindle box (16) with its drill bits (17) towards the mantle of said first cylinder (S₁) and rotating said drill bits (17). Method as claimed in claim 1, characterized by moving said spindle box (16) by transferring a cogged-belt pulley (31) provided in said spindle box (16) and fitted on a ball nut (32) which is assembled on a ball screw (33) on guide shafts (29) which are attached to said frame (11) in a direction towards the mantle of said first cylinder (S₁) by operating said second drive motor (20) in order to rotate a cogged-belt (30) which is operatively connected with said cogged-belt pulley (31). Method as claimed in the preceding claims, characterized in that said first drive motor (18) is fitted in a fixed position relative to said spindle box (16). Method as claimed in any of the preceding claims, characterized by transferring said frame (11) along said guides (12) after each cycle of drilling into the following drilling position. Method as claimed in any of the preceding claims, characterized by rotating said first cylinder (S₁) about a certain angle, whereupon the machining of the next row of holes in the cylinder mantle is started, after the drilling operation has proceeded to the end of said first cylinder (S₁). Multi-spindle drilling machine for drilling holes into the mantle of a first cylinder (S₁) of a paper machine which is provided with at least a second cylinder (S₂) adjacent to said first cylinder (S₁), said drilling machine comprising: a basic frame (11) to be positioned between said two cylinders (S₁, S₂) and slidably supported on guides (12) by means of slide bushings or equivalent, a spindle box (16) with a number of drill bits (17) which are fitted to be rotated by a first drive motor (18), said spindle box (16) being connected to said basic frame (11) and movable relative to said frame (11) in a direction towards the mantle of said first cylinder (S₁) by means of a second drive motor (20), characterized in that said guides (12) are provided with belts (13) or equivalent to fasten said guides to said second cylinder (S₂) in the direction of the longitudinal axis thereof, and in that the drilling machine is provided with a drill guide (19) which is movably supported on said frame (11) and disposed on the opposite side of said spindle box (16) with respect to said guides (12) in order to be facing in use the mantle of said first cylinder (S₁), said drill guide (19) being movable relative to said frame (11) and said spindle box (16) in a direction towards the mantle of said first cylinder (S₁) in order to bring said drill guide (19) in use into contact with the mantle of said first cylinder (S₁) and tension said frame (11) between the mantle of first cylinder (S₁) and the mantle of the second cylinder (S₂). Multi-spindle drilling machine as claimed in claim 6, characterized in that said drill guide (19) is movable by means of an actuator (21) bringing said drill guide (19) into contact with the mantle of said first cylinder (S₁). Multi-spindle drilling machine as claimed in any of the preceding claims 6 or 7, characterized in that said spindle box (16) comprises at least one cogged-belt pulley (31) fitted on a ball nut (32) which is assembled on a ball screw (33) formed on a guide shaft (29), said shaft (29) being attached to said frame (11) guiding said spindle box (16), and in that said spindle box (16) is displaced relative to said frame (11) towards the mantle of said first cylinder (S₁) and away therefrom by a cogged belt (30) which is operatively connected with said cogged-belt pulley (31), said cogged belt (30) being drivable by means of said second drive motor (20). Multi-spindle drilling machine as claimed in the preceding claims, characterized in that said spindle box (16) is transferred on said ball screw (33) by said ball nut (32) which is fitted to revolve in bearing means (34) installed in said spindle box (16), said ball nut (32) being fixed relative to said spindle box (16) in the direction of movement of said spindle box (16) with respect to said frame (11). Multi-spindle drilling machine as claimed in any of the preceding claims 8 to 9, characterized in that said drill guide (19) comprises a guide shaft (28) which has been passed into the central hollow space in the guide shaft (29) of said spindle box (16) and is guided and supported in said space by means of a guide bushing (29b). Multi-spindle drilling machine as claimed in any of the preceding claims 8 to 10, characterized in that said drill bits (17) extend through holes in said drill guide (19).

Inventors: HAKALA JAAKKO, SAVOLAINEN EERO, HAKALA, JAAKKO, SAVOLAINEN, EERO
Applicants: VALMET PAPER MACHINERY INC, VALMET PAPER MACHINERY INC.
Application year: 1991
Main classification: D21F5
IPC codes: D21F5, B23B39