WORKHEAD FOR REMOVING A RAILWAY TRACK FASTENER

Abstract

The present invention relates broadly to an apparatus 10 for removing one of a plurality of railway track fasteners such as 12a to 12h used to secure a pair of laterally spaced railway tracks 14a and 14b to underlying sleepers such as 16a to 16f. The track fasteners such as 12a are each in the form of an e-clip or PR-clip fastener of a known configuration. The apparatus 10 comprises a support frame assembly 20 adapted to locate on the railway tracks 14a/b, a drive assembly 22 mounted to the support frame assembly 20, and a workhead 24 associated with the support frame assembly 20 for removal of the track fastener such as 12a. The workhead 24 comprises a percussion hammer 32 and an associated hammer moil 34 arranged for removal of the fastener 12a. The hammer moil 34 includes a moil mount 38 connected at a predetermined angular offset to a moil head 40. The hammer moil 34 is rotatable relative to the percussion hammer 32 during removal of the track fastener 12a whereby alignment between the moil head 40 and the fastener 12a is maintained.

Claims

1. An apparatus for removing a railway track fastener, said apparatus comprising: a support frame assembly adapted to locate on one or both of a pair of laterally spaced railway tracks; a drive assembly mounted to the support frame assembly, said drive assembly powered to activate a workhead associated with the support frame assembly for removal of the track fastener, the workhead including: a. a percussion hammer; b. a hammer moil including a moil mount coupled to and being in substantial alignment with the percussion hammer, said hammer moil including a moil head having a removal tool adapted to align for contact with the track fastener, the moil head connected at a predetermined angular offset to the moil mount whereby during removal of the track fastener the hammer moil rotates relative to the percussion hammer maintaining alignment between the removal tool and said fastener thereby at least in part compensating for the angular offset between the moil head and the moil mount.

2. An apparatus as claimed in claim 1 wherein the workhead also includes one or more hydraulic or pneumatic cylinders coupled between the support frame assembly and the percussion hammer designed to provide a biasing force to the track fastener whilst it is removed under the influence of the percussion hammer.

3. A workhead for removing a railway track fastener, said workhead comprising: a percussion hammer; a hammer moil including a moil mount mounted to and being in substantial alignment with the percussion hammer, said hammer moil including a moil head having a removal tool adapted to align for contact with the track fastener, the moil head connected at a predetermined angular offset to the moil mount whereby during removal of the track fastener the hammer moil rotates relative to the percussion hammer maintaining alignment between the removal tool and said fastener thereby at least in part compensating for the angular offset between the moil head and the moil mount.

4. A workhead as claimed in claim 3 wherein the percussion hammer is tilted at an angle relative to the track fastener to be removed, the tilt angle being sufficient to provide vertical clearance between the percussion hammer and a fastener adjacent the track fastener to be removed.

5. A workhead as claimed in claim 4 wherein the predetermined angular offset is dependent on the tilt angle of the percussion hammer.

6. A workhead as claimed in claim 3 wherein the moil head includes an eccentric lobe integral with and disposed at the predetermined angular offset to the moil mount.

7. A workhead as claimed in claim 6 wherein the eccentric lobe is configured to effect rotation of the hammer moil toward a neutral position when the removal tool is not in contact with the track fastener for its removal, said rotation toward the neutral position being in an opposite direction to the relative rotation of the hammer moil during removal of the track fastener.

8. A workhead as claimed in claim 6 wherein the removal tool includes a tool mount detachably connected to the eccentric lobe, and a removal pin integral with the tool mount.

9. A workhead as claimed in claim 8 wherein the removal pin extends axially from, and is radially offset relative to, the tool mount to facilitate swinging of the removal pin for maintaining alignment with the track fastener during its removal.

10. A workhead as claimed in claim 8 wherein the removal pin is at least in part shaped complementary to and aligned with an engaged leg of the track fastener.

11. A workhead as claimed in claim 6 wherein the moil mount includes a moil shaft located within a mating coupling of the percussion hammer.

12. A workhead as claimed in claim 11 wherein the mating coupling includes rotation biasing mechanism arranged to cooperate with the moil shaft to, in conjunction with the eccentric lobe of the moil head, bias rotation of the hammer moil in one direction during removal of the track fastener.

13. A hammer moil for removing a railway track fastener, said hammer moil comprising: a moil mount adapted to mount to and being in substantial alignment with a percussion hammer; a moil head connected at a predetermined angular offset to the moil mount, the moil head including a removal tool adapted to align for contact with the track fastener whereby during removal of the track fastener the hammer moil rotates relative to the percussion hammer maintaining alignment between the removal tool and said fastener thereby at least in part compensating for the angular offset between the moil head and the moil mount.

14. A hammer moil as claimed in claim 13 wherein the moil head includes an eccentric lobe integral with and disposed at the predetermined angular offset to the moil mount.

15. A hammer moil has claimed in claim 14 wherein the eccentric lobe is configured to effect rotation of the hammer moil toward a neutral position when the removal tool is not in contact with the track fastener for its removal, said rotation toward the neutral position being in an opposite direction to the relative rotation of the hammer moil during removal of the track fastener.

16. A hammer moil as claimed in claim 14 wherein the removal tool includes a tool mount detachably connected to the eccentric lobe, and a removal pin integral with the tool mount.

17. A hammer moil as claimed in claim 16 wherein the removal pin extends axially from, and is radially offset relative to, the tool mount to facilitate swinging of the removal pin for maintaining alignment with the track fastener during its removal.

18. A hammer moil as claimed in claim 16 wherein the removal pin is at least in part shaped complementary to and aligned with an engaged leg of the track fastener.

19. A hammer moil as claimed in claim 14 wherein the moil mount includes a moil shaft located within a mating coupling of the percussion hammer.

20. A hammer moil as claimed in claim 19 wherein the mating coupling includes rotation biasing mechanism arranged to cooperate with the moil shaft to, in conjunction with the eccentric lobe of the moil head, bias rotation of the hammer moil in one direction during removal of the track fastener.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a workhead for removing a railway track fastener will now be described, by way of example only, with reference to the accompanying drawings in which:

[0028] FIG. 1 is an overall assembly view of one embodiment an apparatus for removing a railway track fastener according to a first aspect of the invention;

[0029] FIG. 2 is a side elevational view of a workhead taken from the apparatus of FIG. 1 depicting an embodiment of a second aspect of the invention;

[0030] FIG. 3 is a perspective view of the workhead of FIG. 2;

[0031] FIG. 4 is another perspective view of the workhead of FIG. 2 in conjunction with a railway track fastener to be removed;

[0032] FIG. 5 is an exploded view of part of the workhead taken from FIGS. 2 to 4 illustrating a hammer moil according to an embodiment of a third aspect of the invention;

[0033] FIG. 6 is a cross section of part of the workhead including the hammer moil taken from FIGS. 2 to 4.

DETAILED DESCRIPTION

[0034] As seen in FIG. 1 there is an apparatus 10 for removing one of a plurality of railway track fasteners such as 12a to 12h used to secure a pair of laterally spaced railway tracks 14a and 14b to underlying sleepers such as 16a to 16f. The track fasteners such as 12e are each in the form of an e-clip or PR-clip fastener of a known configuration having one leg 13e retained within an anchor member 15e associated with its corresponding sleeper 16c whilst an opposing leg is elastically deflected to exert a toe-load on the associated track 14a for its retention (see FIG. 4).

[0035] In this aspect the apparatus 10 comprises a support frame assembly 20 adapted to locate on the railway tracks 14a/b, a drive assembly 22 mounted to the support frame assembly 20, and a workhead 24 associated with the support frame assembly 20 for removal of the track fastener such as 12a. The drive assembly 22 is powered to activate the workhead 24 and the support frame assembly 20 includes a trolley 26 arranged to locate on and span the railway tracks 14a/b. The trolley 26 is designed to assist with movement of the workhead 24 between track fasteners such as 12c to 12h to be removed.

[0036] The support frame assembly 20 of this embodiment also includes a boom assembly 28 to which the drive assembly 22 and the workhead 24 are mounted at opposing respective ends. The boom assembly 28 includes a carriage 30 pivotally mounted to the trolley 26, the carriage 30 permitting: [0037] 1. vertical movement of the workhead 24 into general alignment with the track fastener such as 12a to be removed, the workhead 24 being substantially counter balanced by the drive assembly 22; [0038] 2. movement of the workhead 24 across the trolley 26 between the pair of railway tracks 14a/b for removal of track fasteners such as 12a or 12d from respective tracks 14a or 14b.

[0039] FIG. 2 illustrates the workhead 24 taken from the apparatus 10 of the preceding aspect of the invention. The workhead 24 of this embodiment of this other aspect of the invention is shown in the course of removing the track fastener 12e. The workhead 24 comprises a percussion hammer 32 and an associated hammer moil 34 arranged for removal of the fastener 12e. The percussion hammer 32 is tilted at an angle 36 relative to the track fastener 12e to be removed. The tilt angle 36 is sufficient to provide vertical clearance between the percussion hammer 32 and the adjacent track fastener 12d.

[0040] FIGS. 3 and 4 further depict the workhead 24 of this aspect including the hammer moil 34 of an embodiment of a further aspect of the invention. The hammer moil 34 includes a moil mount 38 connected at a predetermined angular offset shown at 39 to a moil head 40. The moil mount 38 is coupled to and is in substantial alignment with the percussion hammer 32. The moil head 40 includes a removal tool 42 adapted to align for contact with the track fastener such as 12a in anticipation of its removal. The hammer moil 34 is rotatable relative to the percussion hammer 32 during removal of the track fastener such as 12a whereby alignment between the removal tool 42 and the fastener 12a is maintained. That is, the relative rotation of the hammer moil 34 at least in part compensates for the angular offset 39 between the moil head 40 and the moil mount 38. It will be understood that the predetermined angular offset 39 is to a large extent based or dependent on the tilt angle such as 36 at which the percussion hammer 32 is inclined relative to the fastener such as 12a to be removed.

[0041] In this embodiment the moil head 40 includes an eccentric lobe 44 integral with and disposed at the predetermined angular offset 39 to the moil mount 38. The eccentric lobe 44 is configured to allow rotation of the hammer moil 34 toward a neutral position when the removal tool 42 is not in contact with the track fastener such as 12a for its removal. As seen in FIG. 4, in the course of removing the track fastener such as 12e the hammer moil 34 rotates inward of the rail 14b in a clockwise direction as viewed at 46. This relative rotation of the hammer moil 34 assists in maintaining alignment between the removal tool 42 and the fastener such as 12e.

[0042] As best seen in FIG. 5 the removal tool 42 includes a tool mount 48 formed integral with a removal pin 50. The tool mount 48 is detachably connected to the eccentric lobe 44 so that as a wear part it can be easily replaced. The removal pin 50 extends axially from, and is radially offset relative to, the tool mount 48 to facilitate swinging of the removal pin 50 for maintaining alignment with the track fastener such as 12e during its removal. In this embodiment, the removal pin 50 is shaped substantially complementary to and aligned with the engaged leg 13e of the track fastener 12e.

[0043] The tool mount 48 of this embodiment includes a mounting spigot 52 configured to locate within a corresponding mounting cavity 54 provided in the eccentric lobe 44. The tool mount 48 also includes a body part 56 shaped substantially complementary to fit within a corresponding recess 58 formed in the eccentric lobe 44. The removal tool 42 thus relies upon the mounting spigot 52 and body part 56 in conjunction with the corresponding components of the eccentric lobe 44 for interlocking of these two parts. The removal tool 42 includes a retaining pin 60 arranged to releasably engage both the eccentric lobe 44 and the tool mount 48 for retention of the removal tool 42.

[0044] In this example the moil shaft 38 of the hammer moil 34 retractably locates within a mating coupling 62 of the percussion hammer 32. As best shown in FIG. 6 the mating coupling 62 includes rotation biasing means in the form of a pair of locking screws 64a and 64b arranged to cooperate with the moil shaft 38 to bias rotation of the hammer moil 34 in one direction only during removal of the track fastener such as 12a. In this instance the moil shaft 38 includes a pair of bevelled sections 66a and 66b arranged to cooperate with the respective locking screws 64a and 64b to: [0045] 1. abut the left hand face of the upper bevelled section 66a and lower face of the lower bevelled section 66b when the hammer moil 34 is at or close to the neutral position to promote its rotation in an anti-clockwise direction as seen in FIG. 6 during removal of the track fastener such as 12a; [0046] 2. limit rotation of the hammer moil 34 in the anti-clockwise direction as a consequence of abutment between the screw fasteners 64a/b and the right hand and upper faces respectively of the bevelled sections 66a/b.

[0047] It will be appreciated that the locking screws 64a/b also function to axially retain the hammer moil 34 within the mating coupling 62 of the percussion hammer 32. In an alternative embodiment rotation of the hammer moil 34 may be symmetric wherein the moil shaft 38 is shaped in cross-section to cooperate with one or more locking screws for rotation either side of the neutral position. In both embodiments, it will be appreciated that the relatively large eccentric lobe 44 under the influence of gravity returns the hammer moil 34 to its neutral position wherein the removal tool 42 or removal pin 50 realigns in anticipation of removing the next fastener.

[0048] Returning to FIG. 4, the workhead 24 also comprises a guide member 70 designed to assist with location of the removal tool 42 relative to the track fastener such as 12e prior to its removal. The guide member 70 is in the form of a bracket 72 opposing the removal pin 50 of the removal tool 42 with sufficient separation for a fastener such as 12e to be removed. The bracket 72 is designed to: [0049] 1. contact the anchor member 15e, within which the fastener 12e is engaged, for positive location of the workhead 24; [0050] 2. on removal of the fastener such as 12e, catch or restrain it for safety purposes; [0051] 3. react to hammer blows and biasing force associated with the percussion hammer 32.

[0052] The general steps involved in operating the apparatus 10 of the preceding embodiment as follows: [0053] 1. The trolley 26 is maneuvered along the railway tracks 12a/b so that the workhead 24 is generally in the vicinity of the fastener such as 12e to be removed; [0054] 2. The workhead 24 is lowered into close proximity to the fastener 12e; [0055] 3. The workhead 24 with the hammer moil 34 in the neutral position is urged into contact with an end face of the engaged leg 13e of the fastener such as 12e; [0056] 4. The drive assembly 22 is powered to activate the workhead 24 wherein: [0057] i. the percussion hammer 32 contacts the fastener 12e in a hammering action; [0058] ii. force biasing means coupled to the support frame assembly 20 provides a biasing force to the fastener 12e to promote its removal.

[0059] With the workhead 24 of FIGS. 2 to 4, the force biasing means includes a hydraulic or pneumatic cylinder 74 anchored at one end and connected at an opposite end to a fulcrum 76. The percussion hammer 32 is suspended from the fulcrum arm 76 wherein extension of the hydraulic or pneumatic cylinder 74 continues to apply pressure or the biasing force to the fastener 12e for its removal.

[0060] As seen in FIGS. 2 and 4 the tilt angle 36 of the percussion hammer 32 together with the angular offset 39 between the moil mount 38 and the moil head 40 combine to effect rotation of the hammer moil 34. This rotation allows for continued alignment of the removal tool 42 and in particular the removal pin 50 during removal of the fastener such as 12e. The removal tool 50 of this embodiment is maintained in guided alignment with the engaged leg 13e of the fastener 12e via the bore of the anchor member 15e from which it is removed. It will be appreciated that without rotation of the hammer moil 34, the removal tool 42 and in particular removal pin 50 will not automatically maintain alignment with the engaged leg 13e of the fastener 12e. This may result in failing of the removal tool 42 within the anchor member 15e and more generally lacks the extraction efficiency of the preferred embodiment where aligned contact is made between the removal tool 42 or pin 50 and the engaged leg 13e of the fastener 12e.

[0061] Now that a preferred embodiment of the invention in its various aspects has been described it will be understood that the workhead and associated hammer moil for removing railway track fasteners have at least the following advantages: [0062] 1. The workhead can be located for removal of a track fastener without obstruction from an adjacent fastener; [0063] 2. The hammer moil rotates relative to its associated percussion hammer ensuring continued alignment between the removal tool and track fastener for quick and efficient extraction of fasteners; [0064] 3. The hammer moil in one form includes the removal tool as a separate and replaceable wear part; [0065] 4. The workhead in conjunction with the associated drive assembly can be operated safely for effective removal of the fasteners and particularly those fasteners being heavily corroded or broken and typically difficult to extract.

[0066] Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. For example, the support frame and drive assembly may vary from that described provided the workhead includes the core features disclosed in this specification. The hammer moil is preferably associated with the percussion hammer of the preferred embodiment but may alternatively be activated by other means which promotes removal of the railway track fastener. All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.