GB2064416A

GB2064416A - A Movable Roll Mill or Calender Operatively Associated With an Extruder Head

Info

Publication number: GB2064416A
Application number: GB8037395A
Authority: GB
Original assignee: Werner and Pfleiderer GmbH
Current assignee: Werner and Pfleiderer GmbH
Priority date: 1979-11-23
Filing date: 1980-11-21
Publication date: 1981-06-17
Also published as: IT8025368A0; DE2947250C2; GB2064416B; DE2947250A1; IT1133921B

Abstract

A roll mill or calender (9) is installed immediately downstream of an extruder (2), the calender rollers (13) being driven by a drive motor (20) through a transmission gearing (21). The roll mill or calender assembly (9) can be moved by means of a drive (29) out of the working position into a cleaning position (47) and optionally into a position (48) at a distance from the extruder head (2) in which the extruder worm can be removed. To enable the removal of the roll mill or calender assembly (9) into the cleaning position and/or the extruder worm removal position to be performed more easily, the rollmill or calender assembly (9) is mounted for pivotal movement about a pivot bearing, (24) which is arranged at a lateral distance from the longitudinal axis (28) of the extruder (2). The distances through which the roll mill or calender assembly (9) has to be moved are considerably reduced by the location of the pivot axis (23) which determines the track of the swivelling movement. <IMAGE>

Description

SPECIFICATION Roll Mill or Calendar Operatively Associated with an Extruder Head The invention relates to a roll mill or calender which is operatively installed immediately downstream of an extruder head.

The roll mill or Calender is drivable by a motor and is selectively movable between a working position and position in which the installation can be cleaned or serviced.

In a roll mill or calender of this type known for example from German Auslegeschrift 17 04 640 (corresponding to United States serial No.

567,914) a frame for the roll mill or calender is supported for linear sliding in the direction of the longitudinal axis of the extruder with respect to guide tracks, so that for cleaning purposes, after the connection between the extruder and the roll mill or calender has been released, the roll mill or calender can be moved away from the extruder head. An arrangement and configuration which is similar in principle is known from British Patent No. 998,725. To enable this worm of the extruder to be demounted, which is preformed out of the end of the extruder housing directed towards the roll mill, the roll mill or calender must be removed relatively a very long way along the guide means, which is firstly extraordinarily onerous and secondly extravagant of space.

United States Patent 1,109,885 discloses an arrangement where two roll mills or calenders are arranged consecutively to each other, in which one roll mill or calender is slidably displaceable with respect to the other by means of a hydraulic sliding drive. In the case of fluctuations of tension in the material travelling immediately consecutively through the roll mills or calenders, this hydraulically powered sliding drive is modulated in order to achieve a corresponding equalisation of the material tension by variations in the distance between the roll mills or calender.

German Patent 905,005, discloses a similar arrangement in which the roll mills are slidably displaceable by strokes up to a maximum of 1.0 mm on sliding tracks. Dynamometers are fitted in these short sliding strokes, which measures the forces occurring due to the material tension of material to be rolled, and modulate the roll mill drives in the case of variations in force resulting from variations in tension.

The underlying aim of the invention is l:o further develop a roll mill or calender which is operatively installed immediately downstream of an extruder head in such a way as to be movable away from the extruder so that the removal of the roll mill or calender into a cleaning position and/or an extruder worm demounting position is easier to perform.

According to the invention, there is provided a roll mill or calender operatively associated with an extruder head, the rollers of which are coupled for rotary propulsion to a drive motor through a transmission and which can be moved selectively by means of a drive means out of a work position into a cleaning position and optionally into extruder worm demounting position at a distance from the extruder head, wherein the roll mill or calender is mounted for pivotal movement about a pivot bearing which is arranged at a predetermined lateral distance from the longitudinal axis of the extruder.

The nub of the invention is that the distance by which the masses of the roll mill or calender have to be moved are considerable reduced by the swivelling movement. This reduction is of a dual nature, because firstly a removal of the roll mill occurs not only in the direction of the longitudinal axis of the extruder, but also simultaneously laterally thereto, and because furthermore the swivelling movements become shorter with decreasing distance from the swivel axis. In one aspect of the invention the pivot hearing is disposed below the unit comprising the driving means for the calender so that the mass typically consisting of a drive motor and a transmission, which are of necessity extraordinarily large and heavy, need hardly be moved at all, without their connection to the rolls being released.

According to another aspect of the invention the pivot bearing is arranged on the side nearer the extruder of a vertical plane passing through the axes of the rollers and at a distance from this plane. In this way, the component of movement of the roll mill or calender in the direction transverse to the longitudinal axis of the extruder is greater than for a swivelling movement of the roll mill on circular arc sections.

In a further embodiment of the invention the support for the roll mill or calender is supported at mutually spaced bearing positions on sliding tracks which are constructed in the manner of hydrostatic sliding guides.

In yet another embodiment of the invention, the unit drive motor and the transmissions are supported on a sliding track which is constructed in the manner of a hydrostatic sliding guide.

Through such means the frictional forces to be overcome during the swivelling movement are reduced to a minimum.

In another aspect of the invention, the pivot hearing is mounted with freedom of movement in the direction of the longitudinal axis of the extruder. Tlhis ensures also in the case of the further development according to the invention, that thermal expansion of the extruder housing and corresponding sliding of the roll mill or calender are not impeded.

A particularly simple further development of the swivelling drive is achieved by providing the roll mill or calender with a hydraulically operable piston/cylinder drive means serving as the swivelling drive, which drive is articulated at one end to the roll mill or calender and is connected at its other end to a relatively fixed point, wherein the swivelling drive can be articulated by one end selectively to one of two articulation points.

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings in which.~ Figure 1 shows a vertical cross-section through part of an extruder with a roll mill or calender disposed immediately downstream, taken on the line I-I in Figure 2.

Figure 2 shows a plan of the roll mill or calender with the extruder head, seen in the direction of the arrow 11 in Figure 1.

Figure 3 shows a partial section through the pivot bearing made along the section line Ill-Ill in Figure 2, and Figure 4 shows a partial section through a bearing position made along the section line IV-lV in Figure 2.

As shown in Figures 1 and 2, an extruder worm 3, which is provided with helical flight lands 4, is arranged in the housing 1 of an extruder 2, only partly shown. The worm 3 can be driven in rotation in the customary manner, not shown in the drawing. The housing 1 is fixed with respect to the floor 6 at a distance from its outlet flange 5, for example, in the housing region 7. the extruder 2 may be a so-called feed extruder, to which the stock to be treated such as rubber mixtures, is fed cold and then plasticised by kneading and shearing by the helical flight lands 4 during its transport through the housing bore 8 by means of the extruder worm 3, for which purpose external heating may optionally be supplied.

Extruders 2 of this type are generally known. The present exemplary embodiment relates to a single-screw extruder.

A roll-mill or calender 9, a so-called "roller die", is installed downstream of the outlet flange 5 of the extruder 2. The roll mill or calender 9 has a supporting frame 10 which consists of side walls 11 which are mutually connected by cross members 12 (Figure 2). Two rolls 13, 14 are mounted for rotary drive in the side walls 1 The drive occurs in opposite directions, so that in the region of their nip they move in the direction 16 away from the extruder 2. During normal operation the outlet flange 5 of the extruder 2 is connected firmly but detachably to the frame 10 of the roll mill or calender 9 by means of locking bolts 17, which for example may be capable of hydraulic actuation.A so-called wide slit nozzle 18 is provided between the outlet flange 5 of the extruder 2 and the roll nip 15 of the rollers 13, 14, and through it the material leaving the barrel 8 of the extruder 2 in the form of a string is fed to the roll nip 1 5 of the rolls 13, 14 already in the form of a wide, flat flow of material.

The roll mill 9 is arranged on a baseplate 19 attached to the floor 6. The drive system for the rolls 13, 14, which consists of a drive motor 20 and a transmission gear 21, which-as shown in Figure 2~may be combined into a single unit, is also arranged on this baseplate 19. The gear 21, and hence also the drive motor 20 connected to it, is mounted for swivelling about a pivot pin 22 with a vertical swivel axis 23 in a pivot bearing 24. This pivot bearing 24 is arranged in a bedplate 25 constructed between the baseplate 19 and the floor 6 as shown in Figure 3. It is formed substantially by a support means in the manner of a block 26 which is supported with play 27 for movement in the direction of the longitudinal axis 28 of the extruder 2, so that expansion of the extruder housing due to heating is not impeded by the fixed housing region 7.

A swivelling drive 29 constructed as a hydraulically powered piston/cylinder drive, is provided for swivelling the roll mill or calender 9 about the swivel axis 23. The cylinder 30 is articulated to the baseplate 19 connected to the roll mill or calender 9, and the piston rod 31 is articulated to the bedplate 25. The following measures are adopted in order to permit the swivelling movement required.

The side walls 11 of the roll mill or calender 9 are each supported, at two bearing positions 32 mutually spaced in the direction of the longitudinal axis 28, upon sliding tracks 33, 34, of which the sliding track 33 is radially further from the swivel axis 23 than the sliding track 34. The support upon these sliding tracks 33, 34, consisting for example of polished steel, occurs through bearing pieces 35 made for example of bronze fastened to the baseplate 19, which are provided on their sliding side with flat pocketlike recesses 36, (Figure 4) to which lubricant can be fed at a very high pressure, for example of 250 bar through a lubricant feed channel 37 during the swivelling movement, so that a lubricant slip layer develops between the relevant bearing piece 35 and the corresponding track 33 or 34.At a distance from the recesses 36, a lubricant collecting groove 38, in which the lubricant collects and is discharged again through lubricant discharge channels 39, is constructed in the peripheral region of each bearing piece 35. This is therefore a hydrostatic sliding guide. A dirt wiper 40, which prevents the penetration of dirt between bearing piece 35 and sliding track 33 or 34, is provided at the outer edge of each bearing piece 35.

An annular sliding track 41 (Figure 3) is likewise arranged concentrically about the swivel pin 22 in the bedplate 25, and a base plate 19, which carries the gear 21 and the driving motor 20 in this region, is supported on the track 41. For this purpose a similarly annular bearing piece 42 is anchored in the baseplate 19 at this point concentrically to the swivel axis 23, and is provided in the same manner with recesses 43 to which lubricant can be fed under pressure through a feed channel 44. No discharge channel has been illustrated in this context.

As Figure 2 shows, the swivel axis 23, i.e. the pivot bearing 24, is located on the side nearer the extruder 2 of the vertical plane oriented at right angles to the longitudinal axis 28, which passes through the axes 45, 46 of the rolls 13, 14.

Because the roll mill or calender 9 is swivelled for the purpose of cleaning by hydraulic actuation of the swivelling drive 29, out of the position shown by solid lines in Figure 2 into a position spaced from the extruder 2; due to the particular location of the pivot bearing 24 the roll mill or calender 9, during the swivelling movement, is not guided on a circular arc section, but upon a curved path which recedes from the median longitudinal axis 28 more sharply than a circular arc. This is shown by the course of the sliding tracks 33, 34 illustrated in Figure 2.In order to clean the extruder 2 and the roll mill or calender the regition between outlet flange 5 and roll nip 15, therefore particularly to clean the wide slit nozzle 18, it is sufficient to swivel the roll mill or calender 9 into a cleaning position 47 in which an operator has free access to the said parts and regions. On the other hand when-which occurs relatively seldom-it is required to withdraw the extruder worm 3 forwards out of the housing 1 of the extruder 2, then the roll mill or calender 9 must be swivelled into a screw demounting position 48 in which-as indicated in Figure 2 by broken lines~ the extruder worm 3 can be withdrawn out of the housing 1 in the direction of the longitudinal axis 28, without colliding with the side wall 11 of the stand 10 located outside the swivel axis 23.

Because the stroke of the swivelling drive 29 is not sufficient for such an ample swivelling movement, in order to swivel the roll mill or calender 9 out into the worm removal position 48, swivelling into the cleaning 47 is performed first and the piston rod 31 is then released from its articulation point 49 to the bedplate 25 and retracted into the cylinder 30 and connected in that position to a fresh articulation point 50 on the bedplate 25. Upon a fresh supply of pressure fluid to the swivelling drive 29, the swivelling movement of the roll mill or calender 9 out of the cleaning position 47 into the extruder worm demounting position 48 then occurs.

Claims

1. A roll mill or calender operatively associated with an extruder head, the rollers of which are coupled for rotary propulsion to a drive motor through a transmission and which can be moved selectively by means of a drive means out of a work position into a cleaning position and optionally into an extruder worm demounting position at a distance from the extruder head, wherein the roll mill or calender is mounted for pivotal movement about a pivot bearing which is arranged at a predetermined lateral distance from the longitudinal axis of the extruder.

2. A roll mill or calender according to Claim 1, wherein the pivot bearing is arranged beneath the drive means which forms a unit comprising the drive motor and the transmission.

3. A roll mill or calender according to Claim 1 or Claim 2, wherein the pivot bearing is arranged on the side nearer the extruder of a vertical plane passing through the axes of the rollers and at a distance from this plane.

4. A roll mill or calender according to any one of Claims 1 to 3, wherein the calender includes a support means which is supported at mutually spaced bearing positions on sliding tracks which are constructed in the manner of hydrostatic sliding guides.

5. A roll mill or calender according to any one of Claims 1 to 4, wherein the drive motor and the transmission are supported on a sliding track which is constructed in the manner of a hydrostatic sliding guide.

6. A roll mill according'to any one of Claims 1 to 5, wherein the pivot bearing is mounted with freedom of movement in the direction of the longitudinal axis of the extruder.

7. A roll mill or calender according to any one of Claims 1 to 6, and having a hydraulically operable piston/cylinder drive means serving as the swivelling drive, which drive is articulated at one end to the roll mill or calender and is connected at its other end relatively fixed point, wherein the swivelling drive can be articulated by one end selectively to one of two articulation points.

8. A roll mill or calender operatively associated with an extruder head, substantially as herein before described, with reference to the accompanying drawings.