Cutting by use of rotating axially moving tool – Processes – Bit detachable
Reexamination Certificate
1998-12-01
2001-07-24
Wellington, A. L. (Department: 3722)
Cutting by use of rotating axially moving tool
Processes
Bit detachable
C408S042000, C408S077000, C408S092000, C408S099000, C408S110000, C409S177000
Reexamination Certificate
active
06264405
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for drilling holes into a mantle of a cylinder of a paper machine while the cylinder is in its site of operation in the paper machine. The holes are drilled into the cylinder mantle by a drilling device provided with drill bits and which is transferred after each drilling cycle to the next drilling position.
Also, the present invention relates to a drilling device for drilling holes into a mantle of a cylinder of a paper machine while the cylinder is in its site of operation in the paper machine. The device comprises a frame construction, drill bits rotatably mounted on the frame construction and drive means for transferring and rotating the drill bits during each drilling cycle.
BACKGROUND OF THE INVENTION
In the prior art, when effecting modifications to cylinders in a dryer group in a paper machine, e.g., machining or drilling drying cylinders, the drying cylinders were removed from their place and transferred away to be machined separately. Thus, in the prior art, it is known to convert ordinary non-perforated cylinders in a dryer group into so-called “Uno Vac” cylinders by making holes in the cylinder mantle. In the current assignee's Finnish Patent No. 91,135 (corresponding to U.S. Pat. No. 5,090,846, incorporated by reference herein), a method and a device are described by whose means the perforation of the cylinder mantle can be carried out on the site in the paper mill without removing or detaching the cylinder. In this arrangement, a drilling machine moves on support of separate guides in the axial direction of the roll. During the machining process, the drilling unit is supported both on the mantle face of the cylinder to be machined and on the mantle face of an adjacent cylinder. The drilling unit includes a spindle box of a multi-spindle drilling machine which comprises a unit for rotation of the drill bits and connected power transmission means for transferring the rotation to all of the adjacent drill bits at the same time. The drilling unit further comprises a cylinder by whose means the jig of the drill bits, i.e., the drill guide, is displaced or guided into contact with the mantle face of the cylinder to be machined. In this case, since the equipment rests both against the cylinder to be machined and against this adjacent second cylinder, which constitutes a support base for the guides, a continuous, robust construction is formed during machining, which permits a drilling free of disturbance. The drilling unit further comprises a spindle box displaceable with respect to the main frame and in this box, a separate motor for displacing the spindle box with its drills. Further, the drilling unit includes a motor for rotating the drill bits. The drill bits are arranged to drill holes in a horizontal direction.
In the construction in accordance with Finnish Patent No. 91,135, the drill bits are placed in a fixed position in relation to one another. In such a case, the spacing of the grooves on the roll must also be fixed, because it is preferable that the perforations are placed expressly in the bottoms of the grooves. However, the spacing of grooves can vary from cylinder to cylinder.
With further respect to the prior art, reference is also made to the current assignee's Finnish Patent No. 91,834 (corresponding to U.S. Pat. No. 5,334,259, in which an arrangement is described for improving the method and the equipment in accordance with the Finnish patent mentioned above. In this improved arrangement, the spacing of adjacent drill bits in the drill equipment can be adjusted in a desired way.
A drawback of the prior art constructions is that the installation of the guides necessary for fastening of the drill guide has been time-consuming, and in some cases, there has not been enough space to fasten the guides to the cylinder adjacent to the cylinder to be drilled, e.g., if a machine construction with dense spacing of cylinders and a narrow gap between cylinders is involved.
It is a further drawback of the prior art constructions that, in some cases, it has not been possible to carry out the drilling of the holes by means of the drill guide immediately from the edge of the cylinder, but the holes to be placed in the edge areas have had to be drilled manually.
It may be considered a further drawback in the prior art constructions that, when drilling takes place from the side (in a horizontal direction as in both Finnish patents referenced above) or from below (vertically upward), chips etc. may enter into the drill guide and cause problems and also, their removal is problematic.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide overall solutions for the problems and drawbacks mentioned above.
Another object of the present invention is further development of the prior art methods and constructions described above so that the fixing of a drilling device in connection with a cylinder to be machined is simpler and thus quicker than in the prior art arrangements.
It is a further object of the present invention to provide an arrangement in which drill chips do not disturb the operation of the device, in which the chips can also be vacuumed during drilling, and in which the edge areas of the cylinder can also be drilled.
It is still another object of the present invention to provide a method and apparatus to enable accurate drilling or machining of a mantle of a cylinder at its site of operation.
With a view to achieving the above objects and others, in the method in accordance with the invention, the device for drilling holes in a cylinder mantle is supported on the cylinder being drilled, which is situated in a staggered relationship with other supporting cylinders. Before the drilling is started, the device is locked in place in a desired position. By means of drill bits of the device, the holes are drilled in the cylinder in a downward direction. The drill carriage is transferable in an axial direction of the cylinder being drilled to additional fixed positions relative to the cylinder being drilled. Also, the cylinder to be drilled is rotatable while the drill carriage is locked in its axial position over a certain angular distance so as to drill the holes into different circumferential portions of the cylinder mantle.
The drill carriage may be supported on the cylinder being drilled by arranging a first set of wheels on the drill carriage, positioning these wheels on the cylinder to be drilled prior to drilling, and fixing or locking the wheels in position on the grooves prior to drilling. The fixing of the wheels may entail tightening a belt passing around the cylinder being drilled and controlling tension of the belt by means of an actuator to tighten the belt to fix the wheels and to loosen the belt in order to allow movement of the wheels in the grooves upon rotation of the cylinder (but without axial movement of the drill carriage). In use, the locking of the wheels is released while the wheels are maintained in contact with the cylinder such that the cylinder is rotatable but the drill carriage is not displaceable in an axial direction. The cylinder is rotated while the drill carriage is locked in its longitudinal or axial position over a certain angular distance so as to position the drill carriage over different circumferential portions of the cylinder mantle. The wheels are thus fixed at each different location until the entire circumference of the cylinder mantle is drilled and then the drill carriage is moved axially, fixed in position, and then rotated about the circumference. This process continues until, e.g., the entire cylinder mantle is drilled.
Transfer wheels may be arranged on the drill carriage for enabling axial movement of the drill carriage. To this end, the transfer wheels are moved from a first position in which they are out of contact with the cylinder being machined and the other wheels described above are in contact with the cylinder being machined to a second position in which the transfer wheels are in contact with
Parviainen Seppo
Pelkonen Jouko
Reivo Jaakko
Tolvanen Raimo
Ergenbright Erica D.
Steinberg & Raskin, P.C.
Valmet Corporation
Wellington A. L.
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