Head for harvesting of trees and vehicle provided with the improved head
AssigneeGierkink Exploitatie B.V.
InventorMichel Bernardus Johanna Gierkink
Life of this patent
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Abstract
The invention relates to an improved head for harvesting of trees. In particular, the head according to the invention is an improvement of a head for harvesting of trees as disclosed in European Patent EP2515628, which state of art is hereby incorporated by reference. In the known head, the balance between the saw pressure and the saw speed is controlled by the oil pressure at the inlet port of the hydraulic motor. This has the drawback that the saw pressure is depending on the saw speed. It is the aim of the invention to provide an improved head for harvesting trees, wherein the saw pressure is constant and independent of the saw speed.
Claims5
A hydraulically controlled head (2) for harvesting trees, which head is arranged for attachment on a vehicle (1) with a hydraulic pump unit, which head (2) comprises a
- double-action hydraulic valve (6) for connecting to the hydraulic pump unit,
- a clamp (7) for placement round a tree, comprising a first hydraulic actuator (12)
- a tilting device (9) for tilting the clamp (7), comprising a second hydraulic actuator (10),
- a chainsaw (13) for sawing through a clamped tree, comprising a hydraulic motor (14),
- a saw displacement device for causing the blade of the chainsaw to move out of and into a saw casing, comprising a third hydraulic actuator (15) and
- a first pressure line (5a) and a second pressure line (5b), the first pressure line (5a) and the second pressure line (5b) each connecting the hydraulic valve (6) to the first hydraulic actuator (12), the second hydraulic actuator (10) and the third hydraulic actuator (15),
- the hydraulic motor (14) comprises an inlet port (21), a first outlet port (22) and a drain port (27), wherein
- the drain port is connected via a first non-return valve (29) to the first pressure line (5a) and is provided with a first hydraulic accumulator (28),
- and
- the first outlet port (22) is connected via a throttle control valve (23) and a second non-return valve (24) to the first pressure line (5a), and the first inlet port (21) is connected to the second pressure line (5b), wherein the third hydraulic actuator (15) comprises a double-action hydraulic cylinder which is connected to the first outlet port (22) of the hydraulic motor (14) and, via a third non-return valve (26), to a second hydraulic accumulator (25), and
- a hydraulic control unit suitable for controlling the first hydraulic actuator (12), the second hydraulic actuator (10) and the third hydraulic actuator (15) and the hydraulic motor (14),
- wherein the head (2) comprises control means for controlling the saw pressure and the saw speed by the oil pressure at the first outlet port (22) of the hydraulic motor (14).
Vehicle (1) provided with a hydraulically controlled head (2) for harvesting trees, which head is arranged for attachment on a vehicle (1) with a hydraulic pump unit, which head (2) comprises a
- double-action hydraulic valve (6) for connecting to the hydraulic pump unit,
- a clamp (7) for placement round a tree, comprising a first hydraulic actuator (12)
- a tilting device (9) for tilting the clamp (7), comprising a second hydraulic actuator (10),
- a chainsaw (13) for sawing through a clamped tree, comprising a hydraulic motor (14),
- a saw displacement device for causing the blade of the chainsaw to move out of and into a saw casing, comprising a third hydraulic actuator (15) and
- a first pressure line (5a) and a second pressure line (5b) for connecting the hydraulic valve (6) to the first hydraulic actuator (12), the second hydraulic actuator (10) and the third hydraulic actuator (15),
- the hydraulic motor (14) comprises an inlet port (21), a first outlet port (22) and a drain port (27), wherein
- the drain port is connected via a first non-return valve (29) to the first pressure line (5a) and is provided with a first hydraulic accumulator (28), and
- the first outlet port (22) is connected via a throttle control valve (23) and a second non-return valve (24) to the first pressure line (5a), and the first inlet port (21) is connected to the second pressure line (5b), wherein the third hydraulic actuator (15) comprises a double-action hydraulic cylinder which is connected to the first outlet port (22) of the hydraulic motor (14) and, via a third non-return valve (26), to a second hydraulic accumulator (25), and
- a hydraulic control unit suitable for controlling the first hydraulic actuator (12), the second hydraulic actuator (10) and the third hydraulic actuator (15) and the hydraulic motor (14),
- wherein the head (2) comprises control means for controlling the saw pressure and the saw speed by the oil pressure at the first outlet port (22) of the hydraulic motor (14).
Dependencies are inferred from the claim text.