SYSTEM AND METHOD FOR REMOVING EXTRUSION SCREW ELEMENTS

Abstract

An improved system and method for removing extrusion screw elements includes a puller assembly for removing at least one screw element from a screw shaft of a screw-type extrusion machine. The at least one screw element includes a sleeve portion received annularly about the screw shaft and at least one flute extending radially outward from the sleeve portion. The puller assembly includes a body having a sleeve portion with an inner diameter sufficiently sized for axially fitting over the at least one screw element on the screw shaft. At least one engaging element is removably secured to the body for enabling the body to be axially installed on the at least one screw element when the at least one engaging element is removed from the body and axially locking the body on the at least one screw element when the at least one engaging element is installed in the body. The at least one engaging element extends radially inward relative to the inner diameter of the sleeve portion beyond an outer radial edge of the at least one flute when the at least one engaging element is installed in the body to axially lock the body to the at least one screw element. To remove the at least one screw element from the screw shaft, an axial pulling force is applied to the body to axially move the at least one screw element relative to the screw shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of a screw-type extrusion machine shown partially in cross-section to reveal screw elements which are received on a screw shaft of the extrusion machine.

FIG. 2 is a partial cross-sectional view of the screw-type extrusion machine taken along line 2-2 of FIG. 1.

FIG. 3 is an elevational view of the screw-type extrusion machine shown with a portion of the machine's housing removed revealing a plurality of screw elements disposed along an axial extent of the screw shaft.

FIG. 4 is a partial cross-sectional view of the screw-type extrusion machine shown with housing portions of the extrusion machine pivoted away from one another to provide access to the screw shaft and the screw elements received thereon.

FIG. 5 is an exploded perspective view of a puller assembly for removing screw elements from the screw shaft of the extrusion machine.

FIG. 6 is a first axial end elevational view of the puller assembly of FIG. 5.

FIG. 7 is a cross-sectional view of the puller assembly taken along the line 7-7 of FIG. 6.

FIG. 8 is a cross-sectional view of the puller assembly taken along the line 8-8 of FIG. 7.

FIG. 9 is a second, opposite axial end elevational view of the puller assembly installed on the screw shaft and one or more of the screw elements of the extrusion machine (the screw shaft and at least one screw element shown in cross section).

FIG. 10 is a side elevational view, shown in partial cross-section, of the puller assembly installed on a screw element of the extrusion machine.

FIGS. 11A-11F illustrate a process of removing screw elements from a screw shaft of an extrusion-type machine using the improved puller assembly of the present disclosure.

Claims

1. A puller assembly for removing at least one screw element from a screw shaft of a screw-type extrusion machine, the at least one screw element including a sleeve portion received annularly about the screw shaft and at least one flute extending radially outward from the sleeve portion, said puller assembly comprising: a body having a sleeve portion with an inner diameter sufficiently sized for axially fitting over the at least one screw element on the screw shaft; andat least one engaging element removably secured to said body for enabling said body to be axially installed on the at least one screw element when said at least one engaging element is removed from said body and axially locking said body on the at least one screw element when said at least one engaging element is installed in said body, said at least one engaging element extending radially inward relative to said inner diameter of said sleeve portion beyond an outer radial edge of the at least one flute when said at least one engaging elements is installed in said body to axially lock said body to the at least one screw element.

2. The puller assembly of claim 1 further including: a pulling device for selectively applying an axial pulling force to said body to axially move said at least one screw element along said screw shaft, said at least one engaging element engaging said at least one flute to thereby axially force said at least one engaging element to move along said shaft.

3. The puller assembly of claim 2 wherein said pulling device includes: an extension shaft removably secured to one end of said screw shaft;a puller shaft tailpiece annularly disposed on said extension shaft and axially spaced apart from said body;at least one connector element connected to each of said body and said puller shaft tailpiece; anda drive assembly that, upon actuation, moves said puller shaft tailpiece axially along said extension shaft and through said at least one connector element axially moves said body to move said at least one screw element along said screw shaft.

4. The puller assembly of claim 3 wherein said drive assembly is a pneumatic device connected to a compressed air source, said pneumatic device forcibly moving said puller shaft tailpiece axially along said extension shaft upon actuation.

5. The puller assembly of claim 3 wherein said at least one connector element is a plurality of chains extending between said body and said puller shaft tailpiece.

6. The puller assembly of claim 5 wherein said plurality of chains includes at least three chains connected to said puller shaft tailpiece at locations circumferentially spaced about said puller shaft tailpiece and connected to said body at locations circumferentially spaced about said body.

7. The puller assembly of claim 3 wherein said extension shaft has a threaded end threadedly engaged with said one end of said screw shaft.

8. The puller assembly of 1 wherein said at least one screw element is a kneader element or a conveyor element.

9. The puller assembly of claim 1 wherein said at least one engaging element includes at least three engaging elements circumferentially spaced around said body, each of said engaging elements having a radial width substantially greater than an axial width.

10. The puller assembly of claim 9 further including at least one anti-rotation element removably secured to said body and extending radially inward relative to said inner diameter of said sleeve portion beyond said outer radial edge of the at least one flute to prevent significant relative rotation between said body and the at least one screw element.

11. The puller assembly of claim 10 wherein said at least one anti-rotation element has an axial width substantially greater than a radial width.

12. The puller assembly of claim 1 wherein said body includes a plurality of receiving apertures into each of which a corresponding one of said at least one engaging elements is received.

13. The puller assembly of claim 12 wherein each of said at least one engaging elements includes a head portion that is enlarged relative to an elongated portion to limit insertion of said at least one engaging element in said plurality of receiving apertures.

14. The puller assembly of claim 13 wherein each of said plurality of receiving apertures includes a counterbore for receiving said head portion and limiting insertion of said at least one engaging element in said plurality of receiving apertures.

15. The puller assembly of claim 12 further including: a sleeve member annularly received over said sleeve portion to lock said at least one engaging element in said plurality of receiving apertures.

16. The puller assembly of claim 15 further including a securing device connecting said sleeve member to said body to limit relative movement therebetween.

17. The puller assembly of claim 15 wherein said body includes a flange portion that limits axial movement of said sleeve member along said sleeve portion.

18. The puller assembly of claim 17 wherein said flange portion includes a plurality of axial pulling assemblies each having loop members for facilitating axial pulling of said body to axially move the at least one screw element axially relative to the screw shaft.

19. The puller assembly of claim 18 further including: a chain connected to each of said loop members and further connected at a location spaced from said body to a pulling device that selectively applies an axial pulling force to said body to axially move said at least one screw element along said screw shaft upon actuation, said at least one engaging element engaging said at least one flute to thereby axially force said at least one screw element to move along said shaft.

20. A method of removing at least one screw element from a screw shaft of a screw-type extrusion machine, the at least one screw element including a sleeve portion received annularly about the screw shaft and at least one flute extending radially outward from the sleeve portion, said method comprising: axially installing a puller collar onto the at least one screw element;installing at least one engaging element on said puller collar to axially lock said puller collar to the at least one screw element, said at least one engaging element extending radially inward relative to an inner diameter of said puller collar beyond an outer radial edge of the at least one flute; andapplying an axial pulling force to said puller collar to axially move the at least one screw element relative to the screw shaft.

21. The method of claim 20 further including: removing a tip element from an end of the screw shaft;threadedly connecting an extension shaft to the end of the screw shaft;connecting a puller shaft tailpiece to said extension shaft;connecting said puller shaft tailpiece to said puller collar after said puller collar is axially installed onto the at least one screw element and said at least one engaging element is installed on said puller collar.

22. A puller assembly for removing at least one screw element from a screw shaft of a screw-type extrusion machine, the at least one screw element received annularly about the screw shaft with at least one flute extending radially outward, said puller assembly comprising: a body having a sleeve portion with an inner diameter appropriately sized for receipt of the at least one screw element on the screw shaft; anda plurality of engaging elements extending radially inward relative to said inner diameter of said body beyond an outer radial edge of the at least one flute of the at least one screw element, one of said plurality of engaging elements removable from said body for enabling said body to be axially installed on the at least one screw element when said one of said plurality of engaging elements is removed from said body and said plurality of engaging elements axially locking said body on the at least one screw element when said one of said plurality of engaging elements is installed in said body.

23. The puller assembly of claim 22 wherein said plurality of engaging elements includes: at least three axial engaging elements circumferentially disposed around said body wherein each of said axial engaging elements has a radial width substantially greater than an axial width; andat least one anti-rotation engaging element removably secured to the body for preventing significant relative rotation between said body and the at least one screw element.