FI72070B - ANORDNING FOER ATT AOSTADKOMMA RETURGAONG AV ETT KEDJESAOGSSVAERD VID ETT GRIPORGAN - Google Patents

Description

72070 1 Device for returning the chain saw guide in the gripping member

Anordning för att ästadkomma returgang av ett kedjesags-Svärd vid ett griporgan 5

The invention relates to a device for providing a return movement of a chain saw guide in a gripping member, the device comprising a pressure source, a pressure cylinder with a piston and a piston rod protruding from the cylinder connected to the guide so that displacement of the piston rod in its longitudinal direction around, means for supplying pressure medium to the cylinder and for discharging it from the cylinder, respectively, at its piston rod end.

In a known model of devices of the above-mentioned type, an elastic band is used to effect the return movement of the guide. In addition to the very limited life of the rubber band, malfunctions may occur due to the rubber band sticking to protruding parts, such as the remnants of branches.

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Another device of the type mentioned above uses a double-acting hydraulic cylinder controlled by electrically controlled directional valves. However, the electrical cables must be routed to the valves. Not only is this structural solution expensive, but the electrical conductors are also easily damaged in use, for example, if they become entangled in protruding branch remnants.

The object of the invention is to provide a device which avoids the above-mentioned disadvantages. This is done by means of a device implemented with the features set forth in the claims.

An embodiment of the invention will now be described with reference to the accompanying drawings, in which Fig. 1 shows a front view of a log sticker equipped with a device according to the invention, Fig. 2 shows a sluice according to Fig. 1, Fig. 3 shows an embodiment of a hydraulic diagram of a device according to the invention. another 72070 1 embodiment.

The log grapple shown in Figures 1 and 2 is provided with a chain saw 2 which is driven by a hydraulic motor (not shown).

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The chain saw 2 comprises a guide 3 which supports the chain 4. The guide 3 with its chains 4 is pivotally mounted on the log gripper 1.

Alternative shapes of the guide 3 are shown in colon in Figure 1 in colon lines.

The movement of the guide 3 from the rest position (horizontal position in Fig. 1) obliquely downwards to the right in Fig. 1 takes place by means of a hydraulic cylinder 5, the piston rod 6b of which is connected via a connection 7 to the bearing of the saw 2.

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The end of the hydraulic cylinder 5 away from the piston rod 6b is pivotally connected to the log gripper 1 via the connection 8.

When the piston rod 6b is moved to the hydraulic cylinder 5, the guide 3 20 moves downwards in Fig. 1, whereby the bundle of wood held by the log gripper 1 is cut off on the other side of the gripper 1.

Figure 3 shows another example of the connection diagram of the hydraulic cylinder 5. As can be seen from Figure 3, a hydraulic line 7, 25 is provided through which the hydraulic jet is pumped. A hydraulic motor 8 is placed in the line 7, which drives the chain 4 in sawing.

The side line 9 is connected to the line 7. A pressure control valve 10 is connected to the side line 9. In addition, the bypass line 11 is connected to the side line 30 9 on both sides of the pressure control valve 10. A non-return valve 12 is connected to the bypass line 11, which allows flow from the hydraulic cylinder 5 to the hydraulic line 7.

A battery 13 is connected to the end of the hydraulic cylinder 5 remote from the piston rod 6b.

3 72070 1 The system shown in Figure 3 operates as follows: When hydraulic oil is supplied to line 7 to activate the hydraulic motor 8, some of the oil will flow to the side line 9, through the valve 10 and to the hydraulic cylinder 5 on the side of its piston rod. In this case, the piston 6a is moved to the right in Fig. 3, whereby the switch 3 is moved downwards in Fig. 1.

A certain amount of gas is enclosed in the accumulator 13, preferably nitrogen gas, which is compressed as the piston 6a moves to the right.

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When sawing is complete and the clutch has moved to the lowest colon line shown in Fig. 1, the hydraulic oil supply to line 7 is cut off. The amount of air compressed in the accumulator 13 will then apply pressure to the piston 6a, which moves to the left in Fig. 1. to the position shown, whereby the hydraulic oil on the side of the piston rod flows into the bypass line 11, past the non-return valve 12, out into the line 7, past the hydraulic motor 8 and back into the tank.

The pressure control valve 10 ensures that the pressure on the side of the piston rod in the hydraulic cylinder 5 does not become too high, for example if the guide 3 gets stuck.

Within the scope of the invention, it is also conceivable that a fluid, for example 25 hydraulic oil, is enclosed in the accumulator 13 and in the part of the hydraulic cylinder 5 remote from the piston rod 6b. In this case, a rubber film is preferably arranged in the battery 13.

Figure 4 shows an alternative diagram for the field of engagement of the hydraulic cylinder 5.

The side line 14 is connected to the hydraulic line 7 after the hydraulic motor 8. This side line 14 terminates in the hydraulic cylinder 5 on the side of its piston rod. A choke 15 is connected to the hydraulic line 7 after the connection point 35 of the side line 14, viewed in the direction of hydraulic oil flow.

The system shown in Figure 4 operates as follows: 4 72070 1 Hydraulic oil is led to hydraulic line 7. Once <51jy has passed through the hydraulic motor 8, the flow resistance from the choke 15 causes some of the oil to flow to the side line 14, transferring the piston 6a, followed by by turning the controller 3 downwards. When sawing is completed 5, the supply of hydraulic oil to the line 7 is cut off. through, line 7, ku-10 through cross 15 and back to the tank.

In the embodiment according to Fig. 4, no pressure control valve is required in the side line 14, because in case the sawing stops, for example when the chain gets stuck, no hydraulic oil 15 passes through the hydraulic motor 8.

The pressure medium in the battery 13 may vary in a manner similar to that shown in connection with Figure 3.

Although the device according to the invention has been described above in connection with a log gripper, other applications can also be considered within the scope of the invention, for example in connection with a pouring device comprising a gripping member.

Alternatively, the invention may be freely modified within the scope of the following claims.

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Claims (3)

5,72070 An apparatus for providing a return movement of a chain saw guide (3) in a gripping member (1), the apparatus comprising a pressure medium source, a pressure medium cylinder (5) having a piston (6a) and a piston rod (6b) projecting from the cylinder (5) and connected to the guide (3) such that displacement of the piston rod (6b) in its longitudinal direction causes the guide (3) to rotate about its bearing point, means (9; 12) for feeding the bellows to the cylinder (5) and discharging it from the cylinder at its piston-10 end, respectively; characterized in that the accumulator-containing battery (13) is connected to the cylinder (5) at its end remote from the piston rod (6b). 1 Claims Device according to Claim 1, characterized in that the pressure medium in the accumulator (13) is a gas, preferably nitrogen gas. Device according to Claim 1, characterized in that the pressure medium in the accumulator (13) is hydraulic oil and in that a rubber film is arranged in the accumulator (13). 20 25 30 35