TECHNICAL FIELD

The present invention relates to a forwarder with a load area limiter as defined in the preamble to claim 1.

BACKGROUND

By felling forwarders are used to collect and transport timber to a appropriate collection point. The forwarder is equipped with a crane that has a timber grip by which the timber on the forwarder is loaded and unloaded. The forwarder has a load area that is limited by load bunks extending across the longitudinal direction of the load area and a protective screen or a so-called loading gate limiting at the front end of the load area. The amount of timber that can be loaded onto a forwarder is determined by the spatial extent of the load area including length, width, and height.

The amount of timber that can be loaded onto a forwarder is limited by the length, width, and height of the load area. To obtain a low centre of gravity of the load, it is sometimes desirable to be able to maximize the width of the load area. In other cases, it is desirable to be able to minimise the width of the load area, i.e., to make the load area as narrow but as high as possible if, for example, the forwarder is to be driven in forests with limited accessibility.

In this part, it is also desirable to be able to adapt the timber supporting structure of the protective screen to any change in the geometry of the extension of the load area and the timber load both in a horizontal lateral plane in a transverse direction and vertically in a vertical plane. Since the length of logs may vary, it is also desirable to be able to limit the longitudinally extent of the load area in a horizontal plane.

SUMMARY OF THE INVENTION One object of the present invention is to achieve a forwarder with a load area limiter that makes it possible to adapt the load area to the desired geometry of the extension of the load area and the timber load.

This object of the invention is achieved by a forwarder exhibiting the features and characteristics set out in claim 1. Further features and characteristics of the invention are set out in the dependant claims.

According to a first implementation, a forwarder according to the invention comprises a combination of at least two of the following characteristics: a) means of vertically displacing the protective screen in relation to the frame beam and locking the protective screen vertically in desired positions to the frame beam to limit the extension of the load area in a height direction, b) means of displacing the protective screen along the longitudinal direction of the frame beam and locking the protective screen in desired positions on the frame beam to limit the extension of the load area in a longitudinal direction, c) means of laterally adjusting the width of the protective screen, across the longitudinal direction of the frame beam and locking the width of the protective screen in desired position, to limit the extension of the load area in a width direction.

According to another implementation, a forwarder comprises a carriage with several load bunks extending across the longitudinal direction of the frame beam spaced to each other along the length of the frame beam, and where each bunk comprises one bunk and two side limiting struts arranged at the ends of the bunk, the load area limiting unit further comprises the following characteristics:

(d) means of displacement along the longitudinal direction of the frame beam, a load area limiting combination consisting of said protective screen and at least one load bunk and locking said load area limiting combination in the desired positions on the frame beam.

The above combination of features enables a forwarder operator to position the loading gate quickly and efficiently from his driver's seat in relation to the varying geometry of the load area of the forwarder, i.e., both vertically and along the length and the transverse width of a frame beam included in the forwarder.

DESCRIPTION OF THE DRAWINGS In the following, the invention is described in more detail with reference to the attached drawings, on which,

Fig. 1 shows a perspective view of a forwarder with a load area limiting unit according to the invention.

Fig. 2 shows a perspective view of a framework that is part of a load area limiting unit according to the invention.

Fig. 3 shows a perspective view of a protective screen that is part of a load area limiting unit according to the invention.

Fig. 4 shows a plane view of a protective screen when mounted on a framework.

Fig. 4a shows an enlarged detail view of a protective screen sliding guide operative between a framework and a protective screen.

Fig. 4b shows in an enlarged detail view of a frame sled sliding guide operative between a frame sled and an elongated frame beam that is part of the chassis of the forwarder.

Fig. 5 shows a perspective view of a front part of a load area limiting unit according to the invention.

Fig. 5a shows an enlarged detail view of a coupling device by which a load area limiting unit can form a sled combination with a carcass sled by linking.,

Fig. 5b shows a first and second cavity in a load gate carrying framework in which cavities are housed on the one hand a first actuator used for vertically positioning the load gate on the frame beam and, on the other hand, a second actuator used for positioning the frame sled or the combination of sleds on the frame beam.

Fig. 6 shows in a perspective view of an implementation of a protective screen with a first and a second side gate section that are articulately united, each with a side edge section of the protective screen for setting the width of the protective screen.

Fig. 6a shows an enlarged view in detail of a locking means by which it is possible to lock each side gate section partly in an unfolded angular position in which the side gate section forms an extension of the protective screen and partly in a infolded angular position in which the side gate section is transversely aligned with the protective screen.

DETAILED DESCRIPTION OF THE INVENTION In fig. 1 a forwarder 1 is shown which, considered as a vehicle, substantially comprises a combination of a tractor 2 and a load carrier 3 with a load area 4 for timber. The timber is handled using a crane 5 included in the forwarder, which at its front end is equipped with a timber grip. The load carrier 3 is articulated joint with the tractor 1 and has a conventional wheeled chassis 6 with a longitudinal frame beam 7. The term "wheeled" also refers to chassis comprising track units intended for track drive or similar track racks. The load area 4 forms part of an body 8 comprising several load bunks 9 which, extending across the longitudinal directions of the frame beam 7, forms the bottom of the load area and are spaced at mutual distances along the length of the frame beam, and where each load bunk includes one bunk 9b and two side limiting struts 9c at the ends of the bunk, limiting the extension in lateral or width direction of the load area 4.

In accordance with the present invention, the load area 4 in the body of the forwarder 8 is assigned to a usually with 10 designated load area limiting unit, which partly comprises a protective screen 11 extending across the longitudinal direction of the frame beam 7 is limiting of the extension of the load area at its front end, and partly one of the frame beam 7 supported framework 13 which is configured to serve as a carrying support for the protective screen. It should be mentioned that the protective screen 11 also has the function of forming a protective barrier between the load area 4 and the cab 12 of the tractor 2.

As can be seen from fig. 5, the framework 13 is supported by a top of the elongated frame beam 7 which is part of the chassis 8 of the forwarder and along which the body of the frame beam is also displaceable guided. The protective screen 11, shown in more detail in Fig. 3, is intended to be mounted on the framework 13 and is in the mounted position arranged to, with its main plane, extend across the longitudinal direction of the frame beam 7 whereby the framework 13 is configured to serve as a carrying support for the protective screen 11. With the expression main plan Is meant the plane in which the protective screen 11 has its main extension.

To permit the desired extension of a load of timber in accordance with the invention, the load area limitation unit 10 includes at least a combination of two of the following characteristics: a) means of vertically displacing the protective screen 11 in relation to the frame beam 7 and locking the protective screen in the vertically desired positions to the frame beam to limit the vertically extension of the load area 4, b) means of displacing the protective screen 11 along the longitudinal direction of the frame beam 7 and locking the protective screen in the requested positions to the frame beam to longitudinally limit the extension of the load area 4, c) means of laterally adjusting the width of the protective screen 11, across the longitudinal direction of the frame beam 7 and locking the width of the protective screen in required position, to limit the extension of the load area in a width direction.

(d) means of displacement along the longitudinal direction of the frame beam 7, a load area limiting combination consisting of said protective screen 11 and at least one load bunk 9 and locking said load area limiting combination in requested positions on the frame beam.

As means a), to make it possible to vertically displace the protective screen 11 up and down relative to the frame beam 7 and thus also relative to the bottom of the load area 4 defined by the bunks 9b of the load area 4, the load area limiting 10 unit comprises a protective screen sliding guide A operative between the body 13 and the protective screen 11 with which the protective screen 11 is slidable guided on the framework 13. By operating a vertically movable actuator 16 operative between the protective screen 11 and the body 13 (see Figures 4 and 4b), the protective screen 11 can carry out vertically raising and lowering movements and, through the inherent locking effect offered by, for example, a suitably selected hydraulically driven actuator, be locked in certain positions relative to the frame beam 7 and thus also relative to the bottom of the load area 4. It should be understood that said hydraulically operating actuators in the form of a hydraulic cylinder may usefully be provided with a shock valve or similar safety arrangement in their protective shield-lifting hydraulic circuit to more sensitively absorb the shock that may occur if the crane 5 collides with the upper edge of the protective screen 11 during operation.

With reference to fig. 4 and the detail enlargements in Fig. 4a and 4b, the protective screen sliding guide A comprises a pair of safety screen guide rails 14:1, 14:2 designed to form part of a first and second tower respectively (see Fig. 2) which, extending parallel in an upward direction from the framework 13, are situated on opposite sides of one in the framework comprised framework sled 13a supported by a top of the frame beam 7 when the framework 13 is mounted on the frame beam 7 of the forwarder. The protective screen 11 comprises a pair of said protective screen guide rails 14:1, 14:2 corresponding to protective screen guide channels 15:1, 15:2 (see Fig. 3), where each such guide channel consists of an upper and lower relatively short, in cross section, C-shaped guide screen section 15a, 15b (see Fig. 4a) which vertically are located at a distance from each other with oncoming channel openings.

As best shown by the detail enlargement in Fig. 4a, each protective screen guide rail 14:1, 14:2 forms an integral part of a box-shaped element produced from joined sheet metal elements, such as a hollow tower-like beam 18, by the fact that a side section 18:1 of the beam facing the load area 4 is made with a greater width than the beam in general and is so arranged that side edges 18a, 18b of said wider side section protrudes from opposite sides of the beam. Each guide channel 15:1, 15:2 of the protective screen 11 or, more specifically, each C-shaped guide screen section 15a, 15b of the same is designed as an undercut groove in which said wider side section with protruding side edges 18a, 18b of beam 18 is occupied when the protective screen 11 is mounted on the framework 13. As can be seen from a closer study of Fig. 4a each such C-shaped guide screen section 15a, 15b is divisible along its sliding plane by means of a screw means 18c such as a clamping joint or similar. The possibility of opening the undercut grooves of the 15:1, 15:2 protective screen guide channels in this way essentially facilitates by mounting or dismantling work on the protective screen 11 on the tower-like protective screen guide rails 14:1, 14:2 of the framework.

With reference to fig. 5 and 5a, 5b the means b), comprises according to the invention, to displace the protective screen 11 along the longitudinal direction of the frame beam and to lock the protective screen in the desired positions on the frame beam in order to vary the extent of the load area in a longitudinal direction, said to the framework 13 arranged framework sled 13a and a framework sled sliding guide B with which the framework sled 13a and thus the protective screen 11 are slidable carried in a controlled way on the frame beam 7 and adjustable in the required position along the length of the frame beam by the operation of a horizontally operated actuator 19 (see Figure 5b) operative between the framework sled 13A and the frame beam 7.

The framework sled sliding guide B comprises a pair of framework sled guide rails 7:1, 7:2 which are arranged to run parallel along the longitudinal direction of the frame beam 7 and to protrude in a horizontal plane on each side of the long sides of the frame beam.

As best shown in Fig. 5 and 5a the frame beam 7 forms, similar to above described with regard to the construction of each tower, a box-shaped element produced from joined sheet metal elements such as a hollow beam, by that a top 7a of the frame beam is made with a greater width than the frame beam in general and is so arranged that side edges 7b, 7c of the frame beam's 7 upper wider sheet metal element on the upper side 7a protrudes from opposite sides of the frame beam. The framework sled sliding guide B also comprises a pair at the bottom on opposite sides of the framework sled 13a arranged framework sled guide channels 8:1, 8:2 which corresponds to said framework sled guide rails 7:1, 7:2 and to the side edges 7b, 7c protruding from the long sides of the frame beam 7 and which allows the framework sled 13a to be displaced in the longitudinal direction of the frame beam 7 and thus also the protective screen 11 carried by the framework 13 to be adjusted in different positions along the length of the frame beam 7 by the operation of one between the framework 13 and frame beam 7 in a horizontal direction operating movable actuator 19 (see Figure 5b). Due to the inherent locking effect offered by, for example, a suitably selected hydraulically driven actuator, the framework sled 13a can be locked in specified positions along the frame beam 7 and thus also makes it possible to position the protective screen carried by the frameworkl3 in the desired positions on the frame beam 7 in order to limit the longitudinal extension of the load area 4.

Similarto the above description, each framework sled guide channel 8:1, 8:2 includes a C-shaped steering sled section 15a, 15b (see Fig. 5a) in the framework sled direction 15a, 15b (see Fig. 5a) which, viewed in the sliding direction of the framework sled 13a, are located at a distance from each other with oncoming channel openings. Each of said C-shaped guide sled sections 15a, 15b is formed as a groove in which the protruding side edges of the frame beam 7 along the length of the same protruding side edges 7b, 7c are occupied when the framework sled 7a and thus also the framework 13 and the protective screen 11 are mounted on the frame beam 7.

Which should be implied in a closer study of fig. 5a each such C-shaped guide sled section 15a, 15b is divisible along its sliding plane by means of a screw means 15c such as a clamping joint or similar. The possibility of opening the groves of the framework sled guide channels 8:1, 8:2 in this way greatly facilitates mounting or dismantling work of the framework sled 13a on the framework sled guide rails 7:1, 7:2 of the frame beam 7.

With reference to fig. 6 and 6a the means c) comprises, according to the invention, for laterally adjusting the width of the protective screen 11, across the longitudinal direction of the frame beam 7 and locking the width of the protective screen in the desired position to vary the extent of the load area in a width direction, a first and a second side gate section lib, 11c which, like side wings, are carried by and articulated joint with each side edge section of a central gate leaf 11a and around which each side gate section lib; 11c via an upper and lower pin 21a, 21b is pivoting about a vertical axis y-y to the central gate leaf 11a which is illustrated by the double arrows 22 in fig. 6, and is by means of, for example, a locking means 23 operated through pins and holes, with which each side gate section lib, 11c is lockable in a folded out angular position in which the side gate section forms an extension of the central gate leaf 11a as shown in Fig. 6 and a infolded angular position in which the side gate section is transversely aligned with central gate leaf 11a as shown in Fig. 5. Because each pivoting side gate section lib, 11c is carried on the central gate leaf 11a, said respective side gate sections are movably accompanying the protective screen 11 as a whole when performing raising and lowering movements of the same for limiting the load area 4.

With reference to fig. 5, 5a and 5b the means d) comprises, according to the invention, for displacement along the longitudinal direction of the frame beam7, a load area limiting combination consisting of said protective screen 11 and at least one load bunk 9 and locking said load area limiting combination in the desired positions on the frame beam 7, a load bunk sled 9a with which said load bunk is slidably guided carried on the framework sled sliding guide B of the frame beam 7, a coupling device 24 by means of which the bunk sled 9a can form a sled combination with the framework sled 13a by interconnection and which sled combination is adjustable in desired positions along the length of the frame beam by the operation of said horizontally operating actuator 19 (see Figure 5b) operative between the framework sled 13a and the frame beam 7.

Similar to the above description, each load bunk sled 9a, on opposite sides of a bunk 9b, includes a load bunk guide channel 9:1, 9:2, in the form of one on the respective side of the load bunk sled 9a placed, viewed in cross-section, C-shaped guide bunk section 9d (see Figs. 5 and 5a). Each of said C-shaped guide bunk section 9d is formed as a track in which the protruding side edges 7b, 7c of the frame beam 7 along the length of the same protruding side edges 7b, 7c are accommodated when the load bunk sled 9a is mounted on the frame beam 7. As should be implied by a closer study of fig. 5a each such C-shaped guide bunk section 9d is, to facilitate mounting, divisible along its sliding plane by means of a screw means 9c such as a clamping joint or similar.

As is best shown in Fig. 5a, the coupling device comprises a connectable and disconnect able link lever 25 which, via pins 26, is articulated joint to said respective units. As is best shown in 5b, the protective gate carrying framework 13 is formed as a box of joined sheet metal elements and exhibits a first cavity 13d in which the actuator moving in a vertical direction 16 is accommodated and a second cavity 13e in which the actuator 19 moving in a horizontal direction is accommodated. Each such actuator 16, 19 comprises a hydraulic cylinder.