Patent EA-004396-B1 (EA)
Title: Trenching method and apparatus
Inventor: KELLY KEITH RICHARD
IPC: E02F3/10
Filed: 2001-10-19
Abstract: 1. A method of trenching comprising: positioning in a trench a cutting device (23) mounted on a prime mover (21) movable on the ground surface (22) above the trench; positioning the cutting device against the end face of the trench below the level of the ground surface, engaging an end face (54) of the trench with the cutting device and moving the cutting device (23) forward in the trench while operating the cutting device, so as to produce an undercut (55) in the end face of the trench; and operating the cutting device, so as to cut material from the end face of the trench; in which the step of cutting material from the end face of the trench is carried out by moving a plurality of cutting elements (29) along upper and lower runs (30, 31) of an elongate endless support means (28) of device (23) trained along the swinging boom (32) of the cutting device (23), the cutting elements (29) being driven at the distal end of the cutting boom (32) in a direction upwardly around the end of the cutting boom and rearwardly along the upper run (30) relative to the direction (X) of cutting of the trench lifting the upwardly (32), in substantially vertical plane from the undercut to the top of the trench by exerting a force between the boom (32) and the ground surface above the trench and the cutting device during the moving upwardly is put in action in order to cut the material from the end side of the trench. 2. A method according to claim 1 including cutting the trench wider than the endless support means (23) by additional cutting elements of cutting device (23). 3. A method according to claim 1 including cutting the trench wider than the endless support means (28) by operation of a pair of cutting drums (46, 47) extending sideways from the distal end of the cutting boom (32). 4. A method according to any of preceding claims including applying the said lifting force to the cutting boom (32) below ground level. 5. A method according to any of claims including applying the said lifting force at the sides of the cutting boom (32). 6. A method according to any preceding claim in which the step of producing the undercut (55) by driving the prime mover (21) forwardly over the ground while the cutting (23) device is running. 7. A method according to claim 6 in which the said lifting step is carried out by pivoting the cutting boom (32) about a pivot axis (33A) on the prime mover (21), and the said undercut (55) is produced by driving the prime mover (21) forwardly over the ground by driving contact with the ground surface (22) at a position behind the boom pivot axis (33A). 8. A method according to claim 7 in which the said undercut (55) is produced by driving contact with ground surface (22), and at a position behind the boom pivot axis (33A), and at a position forward the boom pivot axis (33A). 9. A method according to any preceding claim in which at the step of producing the undercut (55), the cutting device is installed with the possibility of engagement of the end face (54) substantially on the bottom (19) of the trench. 10. A method according to any preceding claim in which the step of lifting is carried out by moving the cutting device.(23) along an arcuate path defined by pivotal movement of the boom (32). 11. A method according to any preceding claim comprising exerting a force between the cutting device (23) and a region of the ground surface spaced from boom pivot axis (33A) in a forward direction (X) along the trench. 12. A method according to any preceding claim comprising exerting a force between the cutting device (23) and the ground surface (22) in a direction, substantially normal to the boom axis. 13. A method according to any preceding claim comprising the acting of lifting force on cutting device in region of distal end of boom (32) 14. A method according to any preceding claim comprising the acting of lifting force on cutting device in direction inclined to vertical line in straight direction relative to direction (X) of trench cutting. 15. A method according any preceding claim having a predetermined operating cycle comprising: positioning the cutting device (23) against the end face (54) of the trench at the bottom of the trench; moving the cutting device (23) forwardly a predetermined distance in the trench while operating the cutting device (23) so as to produce the undercut in the end face of the trench, by moving the prime mover (21) forwardly over the ground surface (22); lifting the cutting device (23) upwardly from the undercut through the material (56) of the end face while operating the cutting device (23); moving the cutting device (23) rearwardly by a predetermined distance by moving the prime mover (21) rearwardly over the ground surface (22); lowering the cutting device (23); and repeating the previous steps. 16. Trenching apparatus comprising: a prime mover (24); a cutting device (23); mounting structure (24) constructed and arranged to mount the cutting device (23) on the prime mover (21) and to position the cutting device in a trench with the prime mover movable on the ground surface (22) above the level of the trench, said cutting device (23) is installed with the possibility of engagement of the end face (54) to cut the material from the end surface of the trench, in which the cutting device (23)comprises a boom (32) having an elongate endless support (28) carrying a plurality of cutting elements (29) and trained along upper and lower runs (30, 31) on the boom, the boom (32) being mounted to project forwardly and downwardly relative to the intended direction (X) of cutting the trench, said device comprising a drive unit (49) constructed and arranged to drive the endless support (28) in a direction such as to carry the cutting elements (29) upwardly around the distal end of the boom (32) and rearwardly along the upper run (30) of the endless support; and in which the device comprises a lifting means (25) constructed and arranged to lift the boom (32) from an undercut (55) in an end face (54) at the bottom of the trench upwardly to the top of the trench while operating the cutting device in cutting engagement with the end face of the trench so as to cut material from the end face of the trench, the lifting means being constructed and arranged to exert an upward force between the boom (32) and the ground surface (22) above the trench; 17. Apparatus according to claim 16 in which the cutting device comprises further cutting elements to widen the channel cut by the said cutting elements on the endless support (28). 18. Apparatus according to claim 17 in which further cutting elements are mounted on cutting drums (46, 47) extending sideways from the distal end of the cutting boom. 19. Apparatus according to any of claims 16-18 in which lifting means (25) is coupled to the boom (32) at a position such as to apply the said lifting force to the cutting boom (32) below ground level during normal operation. 20. Apparatus according to any of claims 16-19 in which the lifting means (25) is coupled to the boom at the sides of the boom by a pivoted link (59A). 21. Apparatus according to any of claims 16-20 in which cutting boom (32) is mounted on the prime mover (21) for pivotal movement about a pivot axis (33A) to produce the said upward movement of the cutting device (23), and the prime mover (21) is adapted to produce the said undercut (55) at the bottom (19) of the trench by driving the prime mover forwardly over the ground by driving contact with the ground surface at a position behind the boom pivot axis (33A). 22. Apparatus according to any of claims 16-21 in which a lifting means (25) is installed for the acting of lifting force in a direction inclined to the vertical in a direction forwardly relative to the direction (X) of cutting of the trench. 23. Apparatus according to any of claims 16-22 in which the lifting means (25) is located to move the cutting device (23) along an arcuate path defined by pivotal movement of the boom (32). 24. Apparatus according to any of claims 16-23 in which the lifting means (25) is installed for acting of lifting force exertion between the cutting device (23) and the ground surface (22) in a direction substantially perpendicular to the axis of the boom. 25. Apparatus according to any of claims 16-24 in which the lifting means (25) is coupled to the boom in the region of the distal end of the boom. 26. Apparatus according to any of claims 18-25 in which the prime mover (21) includes a rearward crawler chassis (39) positioned to the rear of the boom pivot axis (33A). 27. Apparatus according to claim 26 in which a mobile base (26) is spaced separately forwardly from the boom pivot axis (33A) and coupled thereto for movement therewith. 28. Apparatus according to claim 27 in which the mobile base (26) unit is coupled to the rearward crawler chassis (39) by a framework (27), and the lifting means (25) includes a pivoted arm (59) pivoted to the framework (27) and extending forwardly thereof, a pivoted link (59A) coupled at one end to a forward end of the pivoted arm (59) and at the other end to the boom (32) of the cutting device (23), and a source (40) of lifting force coupled between the arm (59) at a position intermediate the two ends thereof and the framework (27) at a position intermediate the two ends thereof. 29. Apparatus according to claim 27 or 28 in which the mobile base (26) comprises a forward crawler chassis. 30. Apparatus according to claim 16 or 19 in which the lifting means (25) includes an hydraulic ram (40). 31. Apparatus according to any of claims 16-30 in which including control means (34) programmed to carry out a predetermined operating cycle in which: the mounting structure positions the cutting device (23) against the end face (54)of the trench at the bottom of the trench; the prime mover (21) moves the cutting device (23) forwardly a predetermined distance in the trench while operating the cutting device (23), so as to produce the undercut i