Apparatus for removing a cylinder from a screw extruder

Apparatus for removing a cylinder forming the whole or part of the cylinder of a screw extruder, comprising a supporting arm on one end of which the cylinder is pivotally supported, and a further supporting arm to one end of which the other end of said supporting arm is pivoted, the other end of said further supporting arm being pivotally mounted on a base of the screw extruder. Adjusting means may be provided between the cylinder and the outer support arm to adjust the height and inclination of the cylinder, such adjusting means preferably comprising a plate on the support arm, three adjusting set screws in the plate to bear against the cylinder and securing screws to hold the cylinder in the set position.

The invention relates to an apparatus for removing a cylinder forming the 
whole or part of the cylinder of a screw extruder, and has particular 
though not exclusive application to removal of a cylinder from a screw 
extruder with at least one planet rolling member. 
In order to clean or replace the screw or individual sections of a screw 
assembly of a screw extruder it is necessary to remove the extruder 
cylinder or at least a portion thereof. Various removal apparatus have 
been proposed but none is satisfactory due mainly to their complex nature 
and method of operation. 
The invention has among its objects to provide apparatus for removing a 
cylinder from a screw extruder, which apparatus is distinguished by its 
particularly simple method of operation and its minimal technical 
complexity. 
According to the invention there is provided apparatus for removing a 
cylinder forming the whole or part of the cylinder of a screw extruder, 
comprising a supporting arm on one end of which the cylinder is pivotally 
supported, and a further supporting arm to one end of which the other end 
of said supporting arm is pivoted, the other end of said further 
supporting arm being pivotally mounted on a base of the screw extruder. 
For the removal of the cylinder a flanged coupling to the remaining portion 
of the extruder is released. The cylinder can then be withdrawn axially, 
the supporting arms continuously pivoting about their vertical pivot axes. 
During the removal process the cylinder is continually supported by the 
supporting arms. On completion of the removal process it is possible, due 
to the pivotal coupling of the cylinder to said supporting arm, to pivot 
the cylinder member sideways. Thus good access to the screw can be 
obtained. 
The invention makes it possible to remove a cylinder without taking special 
technical precautions. Understandably, the cylinder can be mounted equally 
easily by reversing the removal method. 
Advantageously adjusting means is disposed between the cylinder and said 
supporting arm for adjusting the height and inclination of the cylinder 
with respect to said supporting arm. This enables the cylinder to be 
aligned so precisely at the time of the initial mounting that the cylinder 
can always be re-mounted after each removal process in the originally 
selected position with regard to a remaining portion of the extruder 
cylinder. 
In an advantageous construction the adjusting means comprises a plate 
mounted on said one end of said supporting arm, adjusting set-screws 
screwed into the plate and to bear against the cylinder and securing 
screws extending through the plate and engaged in screw threaded 
aperatures in the cylinder. By way of the set-screws the cylinder can be 
aligned with the remaining portion of the extruder cylinder during the 
initial mounting process. This position is maintained by tightening the 
securing screws.

Referring to the drawings, a planet rolling extruder illustrated in FIGS. 1 
to 3 has drive means 7, whereon a cylinder 8 for a filling screw, not 
visible here, is mounted. The cylinder 8 is supported by way of supporting 
members 9, 11 on a machine base 12. Material to be extruded is supplied to 
the cylinder 8 by way of a filling hopper 13. A second cylinder 14 is 
flanged to the downstream end of the cylinder 8, and is designed to 
receive a planet rolling assembly. The cylinder 14 of the planet rolling 
assembly, a main shaft 15 of which is illustrated in FIG. 3, is supported 
by the machine base 12 by way of two supporting arms 16 and 17. The 
supporting arms 16 and 17 have swivel hinge connections to the cylinder 14 
and the machine base 12 as well as to one another. As can be seen from 
FIG. 2, when the planet rolling extruder is in operation the supporting 
arms extend substantially at right angles to the longitudinal axis of the 
planet rolling extruder. 
When the cylinder 14 of the planet rolling assembly is to be removed, a 
screwed-on end ring 18 is first removed. After first removing a thrust 
ring, not illustrated, planet shafts 19 (FIG. 2) are screwed out by 
rotating the main shaft 15. After breaking a connection between the 
cylinder 14 and the cylinder 8, the cylinder 14 of the planet rolling 
assembly 15, 19 can be removed in a simple manner in an axial direction 
(FIG. 3). The weight of the cylinder 14 is borne during removal by the 
supporting arms 16, 17. Pivoting movement of the cylinder 14 after removal 
is possible. 
FIG. 4 illustrates in more detail the pivotal mounting of the supporting 
arm 16 on the machine base 12. Bolted onto the front of the machine base 
12 is a plate 20 having two spaced horizontal limb plates 21 and 22 welded 
thereto. Aligned bores 23 and 24 are provided in the limb plates 21 and 22 
respectively. An end portion 25 of a pin 26 projects into the bore 23 of 
the upper limb plate 21, a head 28 of the pin 26 being drawn towards the 
external surface of the lower limb plate 22 by way of a screw 27 engaged 
in the pin 26 and acting on a washer bearing on the upper limb plate 21. 
The inner end of the supporting arm 16, which comprises a sleeve 29 with 
welded-in bushes 31 and 32, projects between these two limb plates 21 and 
22. The upper bush 31 has a bore 33, in which a radial roller bearing 34 
is inserted to support the end portion 25 of the pin 26. A combined 
radial-axial bearing 36 is inserted to support the fixed pin 26 in a 
stepped bore 35 of the lower bush 32. A brake screw 37 inserted in the 
upper limb plate 21 serves to slow down the movement when the cylinder 14 
is pivoted. 
FIG. 5 illustrates the swivel connection of the supporting arms 16 and 17 
with one another. The end of each supporting arm has a respective sleeve 
38 and 39 welded thereto with two respective bushes 41, 42 and 43, 44 
welded therein. An end portion 45 of a pin 46 projects into the bore 47 of 
the upper bush 43 of the supporting arm 17. A screw 49 is screwed into 
this pin 45 and is supported by way of a washer 48 on the upper bush 43. 
In this way the pin 46 is drawn towards the under surface of the upper 
bush 43. An axial bearing 51 is inserted in the lower bush 44 of the upper 
supporting arm 17, adjacent to which axial bearing is a radial bearing 52, 
which is inserted in the upper bush 41 of the lower supporting arm 16. 
The lower bush 42 of the supporting arm 16 has a bore 53, into which an 
annular projection 54 of a bearing ring 56 fits, the bearing ring 56 
having a part-spherical inner surface 57 and being secured by way of 
screws 55 to the bush 42. With this part-spherical inner surface 57 is 
engaged a matching radial bearing 58, supporting a lower portion 59 of the 
pin 46. A clamping ring 61 is mounted firmly on the lower end portion 59 
to secure the radial bearing 58. 
FIG. 6 illustrates the swivel connection of the cylinder 14 to the upper 
supporting arm 17. This shows adjusting means 62 disposed between the 
supporting arm 17 and the cylinder 14. The adjusting means 62 comprises an 
adjusting plate 63 with a pin 64 welded thereto, which pin 64 is mounted, 
by a combined radial-axial bearing 68, in the bore 65 of a bush 66 of a 
sleeve 67 welded on the end of the upper supporting arm 17. Three 
set-screws 69 are screwed into the adjusting plate 63 and bear against 
projections 71 and 72 on the cylinder 14. In addition the adjusting plate 
63 has three through-bores 73, through which securing screws 74 pass, the 
securing screws engaging in tapped bores in the projections 71 and 72 of 
the cylinder 14. In this way the adjusting plate 63 is securely but 
adjustably connected to the cylinder 14 in a manner such that the 
orientation and height of the cylinder 14 can be adjusted with respect to 
the supporting arm 17. 
A bore 76 in a lower bush 75 of the sleeve 67 of the upper supporting arm 
17, receives an annular projection 77 of a bearing ring 78 having a 
part-spherical inner surface. The bearing ring 78 is secured by means of 
screws 79. Engaged with the part-spherical inner surface of the bearing 
ring 78 there is a matching radial bearing 81 which supports an end 
portion 82 of the pin 64. A clamping ring 83 is firmly mounted on the end 
portion 82 to secure the radial bearing 81. 
When the cylinder 14 is initially mounted on the cylinder 8 the projections 
71 and 72 of the cylinder 14 are engaged with the adjusting plate 63. The 
cylinder 14 is aligned with the cylinder 8 by means of the three 
set-screws 69, which form a three-point bearing. After alignment the 
cylinder 14 is secured firmly in the aligned position by tightening the 
three securing screws 74. 
To remove the cylinder 14, bolts clamping the cylinder 14 to the cylinder 8 
are removed and the cylinder 14 pulled away from the cylinder 8 causing 
the arms 16, 17 to move from the position of FIGS. 1 and 2, where they 
extend obliquely transverse to the axis of the cylinder 14, to the 
position of FIG. 3 where they extend generally parallel to the axis of the 
cylinder 14.