This invention relates to treatment equipment, including a beam, for a paper machine, the beam having a shaft at both of its end components, equipped with a bearing assembly, which is attached to the paper machine frame and adapted to allow the beam to pivot in relation to the bearing assembly and move in the axial direction, and the said treatment equipment further comprising a support device at least in one of the end components of the beam for turning the beam, and an oscillator for moving the beam back and forth in the axial direction, and the said support device comprising a swing arm immovably set on the shaft and an actuator connected thereto. The invention also relates to similar treatment equipment without an actuator.
Several doctors are used in paper machines as well as in other forming machines. In connection with rolls and cylinders, in particular, the doctors are used to remove the paper web to the pulper. The doctor is also used to clean the surface of a roll or a cylinder. The surface to be cleaned is usually doctored with a doctor blade, which is attached to the doctor beam by means of its blade holder. The beam is supported by its shafts with bearing assemblies, which allow the beam to move in the axial direction as well. As the result, an oscillator arranged in the doctor provides a lateral oscillating movement for the beam, which improves the cleaning performance and reliability of the doctor blade. At least at one end of the beam, the shaft is additionally fitted with a support device, which enables turning the doctor to the desired position by using the actuator of the support device. In addition to turning, the support device also keeps the doctor in the adjusted position.
A Finnish utility model No. 3718 sets forth a doctor, in which a simple hydraulic cylinder can be used as the actuator for the support device. The hydraulic cylinder is connected to a swing arm included in the support device, and the swing arm is connected to a shaft. Between the swing arm and the shaft there is a cogged joint, which not only permits the oscillating movement, but also transmits the turning movement. That is, the swing arm is kept in place during the shaft movement. However, the manufacture of a cogged joint is laborious and expensive. In addition, the proposed support device requires a large installation space, especially in the vertical direction. The cogged joint also inevitably becomes large in size, and remarkable frictional forces are then generated on its counter surfaces, which increases the power requirement of the oscillator. Furthermore, turning of the beam for example to the service position is impossible.
Doctors are also used in coating as well as without an actuator for turning the beam. In this case the beam is set to a desired position and the doctor blade is turned by means of loading hoses adapted to the blade holder. In the prior art technique, the swing arm arranged in the beam is supported to the bearing assembly or generally to the paper machine frame by means of a turnbuckle screw. In this case, the oscillating movement of the beam makes the turnbuckle screw swing, which further leads to distortion of the beam. In practice, the beam is in a continuous rotary motion, which produces uneven wear of the doctor blade. Also, the frictional force generated by the doctor blade varies, which makes the resistance caused by the doctoring vary. For example, the dryer groups of a paper machine have several doctors. The effect of resistance is remarkable, when the resistance peaks of several individual doctors apply simultaneously. In this case, running of the entire paper machine becomes jerking, which hampers the production and causes web breaks. This jerking also stresses the gearings and the electric motors actuating them.
The object of this invention is to provide novel treatment equipment, including a beam, for a paper machine, being more economical to manufacture and use than heretofore and having a larger opening angle than before. Another object of the invention is to provide treatment equipment, with which the disadvantages of the prior art technique are avoided. The characteristics of the treatment equipment according to this invention become evident from the appended claims 1 and 8. In the treatment equipment according to the invention, the support device has a novel design, which permits both the turning movement and the axial movement of the beam. In spite of this, the support device and its actuator, if any, can be securely attached without harmful bending stresses. Also, the construction is easy to install in existing treatment equipment. In addition, the construction requires only a reduced space for installation. Additionally, the application of the support device is independent of the doctor or oscillator used. With a simple design, the back and forth rotary motion of the beam caused by oscillation can be avoided.
The invention is described below in detail by making reference to the enclosed drawings, which illustrate some of the embodiments of the invention, in which
a is a principal drawing of a front view of the doctor according to the invention shown in the machine direction,
b is an axonometric view of the end component of the treatment equipment according to the invention,
a is a top view of the end component of the treatment equipment according to the invention,
b is a sectional side view in plane A—A of the end component illustrated in
a shows a part of the support device illustrated in
b shows a second embodiment of the component illustrated in
c shows the counter component of
a shows a modification of the part of the support device illustrated in
b is s sectional view in plane B—B of
a is a side view of the second embodiment of the end component of the treatment equipment according to the invention,
b is a top view of the end component of
a shows the brackets of the treatment equipment according to the invention at the first end station of the oscillating movement,
b shows the brackets of
In
In addition to the above, the doctor 10 also comprises a support device 18 at least at one of the ends of the beam 12. In
For clarity, the actuator is not shown in
To enable the axial movement of the swing arm 19 the connection 22 comprises elements, composed of roller bearings 25 or slide bearings 26. Generally the roller element 27 included in the roller bearing 25 is arranged in the swing arm 19 or in the auxiliary arm 21. In this case, there are axial direction counter surfaces 28 arranged correspondingly in the auxiliary arm 21 or the swing arm 19 for the roller element 27. In
a shows the swing arm 19 of
The roller bearing can also be made clearance-free by arranging at least two roller elements 27 in it for example as shown in
a and 5b show a second embodiment of the treatment equipment according to the invention. Here the shaft 15 is supported to the beam 12 by means of an intermediate arm 35. In this case the swing arm 19 is composed of a combination of lugs 37, beam 12, and intermediate arm 35. In this embodiment, too, the auxiliary arm 21 is mounted by bearings on the same swing axis as the shaft 15.
Such treatment equipment also exists in which the above described actuators are not needed. In these treatment devices the beam is immovably fixed to a certain position. For loading and adjustment, the blade holder is equipped with separate loading elements. That is, the beam is fixed in a certain position by means of a support element arranged in the end component. According to the invention, the support element is composed of the auxiliary arm 21 arranged in connection with the bearing assembly 16. The auxiliary arm 21 is unexpectedly adapted to the same direction as the swing arm 19 and locked in both radial and axial directions in relation to the bearing assembly 16. In addition, there is a connection 22 between the swing arm 19 and the auxiliary arm 21, allowing for the swing arm 19 to move in the axial direction in relation to the auxiliary arm 21 without a radial distortion of the swing arm 19. In this case the swing arm can move freely in the axial direction together with the beam.
a and 6b show a swing arm 19 and an auxiliary arm 21 connected with a double joint 40. In practice, the auxiliary arm is kept in place all the time while the swing arm is moving axially. The double joint 40 enables this movement while it simultaneously transfers the support force from the auxiliary arm to the swing arm. A double joint is extremely maintenance-free and withstands various operating conditions. Consequently, it can be well applied in difficult paper machine conditions. In addition to the proposed, the connection can include elements that enable the axial movement of the swing arm, composed of roller bearings or slide bearings, as in the above described embodiments of the treatment equipment equipped with an actuator.
The treatment equipment according to the invention and especially the associated connection that enables the axial movement is simple and reliable. The connection can be implemented in many different ways providing a suitable connection for the treatment equipment concerned. In addition, the connection requires only a reduced installation space and generated frictional forces are small. The connection can also be easily made clearance-free, which eliminates vibration problems of the beam.
Number | Date | Country | Kind |
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20035033 | Mar 2003 | FI | national |
Number | Name | Date | Kind |
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4372203 | Brasa | Feb 1983 | A |
4637338 | Wohrle | Jan 1987 | A |
5868841 | Halmschlager | Feb 1999 | A |
Number | Date | Country | |
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20050121164 A1 | Jun 2005 | US |