FI65756C - FOERFARANDE OCH ANORDNING FOER AVSTOETNING AV STOCKAR - Google Patents

Description

χ 65756

This invention relates to a method and apparatus for kicking logs. The kicking of the logs is optionally performed in the desired direction as the logs travel on the longitudinal conveyor.

Finnish patent publication 55 819 discloses a log kicking device in which logs are kicked in the desired direction by a kicking member operated by two pressure medium, double-acting cylinders. When kicking, the cylinders act in different directions, so that one cylinder is pushed and the other is pulled. At the end of the kicking, the driving cylinder tends to brake the movement of the kicking member. However, due to the larger surface area of the pushing cylinder and the larger torque arm, the kicker will continue to move unless the direction of the pressure medium acting on the pushing cylinder is changed at the end of the kicking. For this reason, the control of the kicking member to achieve a suitable kicking movement requires either limit switches or a time relay. Furthermore, when double-acting cylinders are used, the kicking moment of the cylinders is approximately the same throughout the kicking movement. However, the smallest logs required at the same time with the lowest kicking moment only touch the kicker at the end of the kicking movement. Thus, the constant torque kicker is oversized for small supports, while also consuming extra pressurized medium. Due to the high consumption of the pressure medium, the pipelines, pressure accumulators and power units have to be dimensioned large. Furthermore, the kicker according to patent publication 55 819 cannot be stopped in the extreme position of the working movement. During the return movement of this reason, the opposite side of the kicker can not kick that has run into a log kicker due to the immediate return of the movement.

The object of the present invention is to provide a method and a device for kicking logs, which method and device make the operation simpler and more reliable than the prior art device, in addition to which the apparatus is simpler and cheaper because the pressure medium volume flows are lower and the control apparatus is simpler.

2 65756

The advantages of the method and device according to the invention are achieved by a method and a device, the characteristic features of which are given in the appended claims.

The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 shows a device according to the invention in a position where no kicking is performed and Figure 2 shows the same device when a log is kicked from left to right as seen in Figure 2.

The device 1 consists of a frame 2 with a longitudinal conveyor 3 at the top. The longitudinal conveyor shows a log 4. The number 5 denotes a kicking member which is mounted on the frame 2 by means of a bearing pin 6. In addition, the device comprises two cylinders 7 and 8 with a pressure medium, articulated at their lower part to the body at points 71 and 81, and at the top into a kicking member at points 72 and 82. On the side of the cylinders there are also connectors 73 and 83 for introducing pressure medium into the cylinders. As can be deduced from one connector, the cylinders are single-acting, i.e. both cylinders 7 and 8 are traction cylinders, whereby the pressure medium is led only to the piston rod side part of the cylinder.

The operation of the device is as follows. In the waiting position, in which the kicking member 5 is centered as shown in Fig. 1, a pressure medium is introduced into the piston rod part of both working cylinders 7 and 8 by means of connectors 73 and 83. Since identical cylinders are usually used, their traction forces are equal and since the connection points of the piston rods of the cylinders to the kick member 5 are identical on both sides of the bearing point 6 of the kick member 5, the position of the kick member in the waiting phase is symmetrical with respect to the conveyor 3. When it is desired to perform kicking in either direction, one of the cylinders 7, 8 is depressurized, whereby one of the cylinders, i.e. the one in which the pressure acts, pulls the kicking member 5 to a position where points 6, 72 and 71 or resp. 6, 82 and 81 are on the same line. The kick arm stops at said position. If it is desired to return the kick arm to the waiting position, the working cylinder previously depressurized is pressurized. In this case, the arm 5 returns to its waiting position and stops at exactly the desired point, where the moments caused by the cylinders on the arm 5 are equal. It goes without saying, as already mentioned above, that the kicking direction can be chosen as desired by depressurizing the opposite cylinder.

The device with two single-acting pressure medium supply cylinders in question achieves considerable advantages compared to the device with double-acting cylinders. Thus, the kicking movement in this device is very precise, since the kicking angle depends entirely on the mutual distance and position of the joint point 6 and the joint points 72 and 82 of the upper end of the piston rods. The end position of the kick arm 5 is determined, as already stated above, by the position of the points 6, 72 and 71 or 6, 82 and 81 with respect to each other, for which reason the end position of the arm 5 is always exactly the same. Since a higher thrust is required at the beginning of the movement than at the end, this solution is also automatically arranged in such a way that the torque arms between the joint 5 of the shaft 5 and the upper attachment points of the piston rods are large at the beginning and decrease towards the end of the movement. Thus, the above purpose has been achieved completely automatically and in a very simple manner.

This device still offers some advantages over the double-acting cylinder device. Namely, the consumption of the pressure medium in the cylinders in question is considerably lower, with the kicking moment being approximately inversely proportional to the kicking motion. In a device using double-acting cylinders, when the kicking moment is approximately constant, the consumption of the pressure medium becomes higher. For this reason, in the new device according to the invention, the pipelines and power units can be dimensioned for smaller flows, in addition to which any pressure accumulators can also be dimensioned smaller or possibly omitted altogether. This results in significant savings in equipment costs. It can also be mentioned that the kicking operation can be controlled either manually or automatically by means of a single three-position valve, whereas the solution referred to in the general part of the description requires two valves and in addition separate limit switches, etc. to control the operation. In the above-mentioned solution, a limit switch is used to determine the end moment of the work movement, or the end moment is determined by timing the work stroke very accurately. The latter method is the simpler of the two methods, although in the event of a malfunction there is a high risk of damage to the device.

In the device in question, the cylinders can be controlled, for example, by a pulse depending on the travel of the conveyor. The pulse length is set slightly longer than the minimum length required by the movement. Thus, upon receipt of the command, the kicking member turns and stops at its end position, but only begins the return movement after the pulse has ceased.

In the event that the conveyor stops for one reason or another, and the pulse depending on the distance traveled by the conveyor does not stop, the kicking member would turn to its extreme position and remain in it. A device according to the earlier patent referenced earlier, when controlled in a similar manner, would collide with the conveyor body in a similar situation, which would very likely cause considerable economic damage.

Claims (5)

65756 A method for kicking logs in a device comprising a longitudinal conveyor (3) mounted on a frame (2) for transporting a log (4) and a kicking member (5) pivotally mounted transversely around the bearing pin (6) and for mounting two a pressure medium-operated cylinder (7, 8), characterized in that the logging of the logs is effected by means of single-acting working cylinders (7, 8) by depressurizing the desired working cylinder and returning the kicking member (5) to its initial position by depressurizing said cylinder. Method according to Claim 1, characterized in that only traction forces are applied to the kicking element (5) by the working cylinders. Method according to Claim 1 or 2, characterized in that the working cylinder (7 or 8) rotates the kicking element (5) in its working phase until the fastening points (71, 72 or 81, 82) of the working cylinder form a straight line with the bearing pin (6) of the kicking member. wherein the torque caused by the working cylinder relative to the kick member is zero. A device for kicking logs, comprising a longitudinal conveyor (3) mounted on a frame (2) for a log (4), a kicking member (5) mounted (6) on the frame (2) and two pressure-acting working cylinders (7, 8) for turning the kick member by a bearing pin (6), it is known that the working cylinders (7, 8) are single-acting. Device according to Claim 4, characterized in that the working cylinders (7, 8) are hydraulically driven drive cylinders.