WHEEL LOADER

Description

[0001] The invention relates to a wheel loader with a lifting frame extending in a working direction, an attachment arranged at the free end of the lifting frame and a lifting cylinder having one end articulatedly connected to the lifting frame.

[0002] Such wheel loaders are commonly known and, with respect to the attachment, essentially have two functions: lifting / lowering and tipping, which are performed by dedicated working cylinders, usually designed as hydraulic cylinders. These movements are usually performed by an operating lever that performs lifting / lowering in the longitudinal direction of the vehicle and tilting and unloading transversely.

[0003] If the wheel loader is configured as a swivel loader, the attachment can also be swiveled 90° to the left or right. For this purpose, the lifting frame is attached to a swiveling pivoting base. Swiveling is performed either by a foot pedal perpendicular to the direction of travel or by a control lever that can be rotated around the vertical axis.

[0004] Typical attachments used on wheel loaders include forks or buckets for transporting general cargo and bulk materials.

[0005] Although such wheel loaders are generally advantageously designed, they have the problem that they have to be driven very close to the location where the general cargo or bulk material is to be unloaded or picked up. This problem is particularly prevalent on construction sites with areas that are inaccessible due to obstacles.

[0006] Document EP 0 373 148 discloses a wheel loader with a lifting frame extending in the working direction, an attachment arranged at the free end of the lifting frame, and a lifting cylinder pivotally connected to the lifting frame at one end. A head plate, an actuator, an offset cylinder, a first arm, and a second arm are pivotally connected so that a change in the length of the offset cylinder causes an offset of the lifting frame.

[0007] The object of the invention is therefore to provide a wheel loader which can pick up and unload piece goods and bulk goods without the wheel loader being located directly at the location where the goods to be picked up or unloaded are to be picked up or unloaded.

[0008] This object is achieved according to the invention by the wheel loader having the features of claim 1. The subclaims reflect advantageous embodiments of the invention.

[0009] The basic idea of ​​the invention is to design a wheel loader with offset kinematics, particularly designed as a parallelogram, which enables a substantially horizontal movement of the lifting frame and thus of the attachment in the working direction without the vehicle having to move in the working direction. The working direction corresponds to the vehicle's longitudinal axis when the bucket unit is aligned straight or to the plane of the longitudinal axis of the lifting frame when the swivel chair is pivoted. This makes it possible for the vehicle to be positioned at a distance from the unloading or picking up location of the piece or bulk material and for the piece or bulk material to be picked up or unloaded, even if an obstacle prevents the wheel loader from approaching the location directly.

[0010] A wheel loader is therefore proposed with a lifting frame extending in a working direction, an attachment arranged at the free end of the lifting frame, and a lifting cylinder, which is pivoted in particular approximately centrally and is connected at one end in an articulated manner to the lifting frame. According to the invention, a head plate is provided with a first arm which is pivotally attached to the head plate and whose free end is connected to a working cylinder (hereinafter referred to as the offset cylinder) which is pivotally attached to the head plate. The end of the lifting frame opposite the attachment is pivotally connected to the free end of the first arm, and the lifting cylinder is pivotally connected at its other end to an actuator which is pivotally connected on the one hand to the free end of the first arm and on the other hand to the free end of a second arm which is pivotally connected to the head plate.With this configuration, a change in length of the adjustment cylinder causes the lifting frame to be adjusted in the plane of the working direction.

[0011] According to the invention, it is thus possible to move an attachment device further in the working direction when the vehicle can no longer move forward due to an obstacle. Although such a movement can basically also be achieved with a telescopic device - the direction of movement, however, strongly depends on the angle at which the telescopic device is oriented with respect to the ground. In the case of a high shelf, the telescopic device would be oriented at an angle of 45° to 80° upwards and thus the telescopic movement would not be horizontal but diagonally upwards. This disadvantage does not occur with the configuration according to the invention.

[0012] Preferably, the lifting frame, the first arm, and the offset cylinder form a common joint with a common axis of rotation. This configuration enables a particularly stable and space-saving construction of the wheel loader designed according to the invention.

[0013] The actuator is preferably triangular in shape, with the first arm, the second arm and the lifting cylinder each being articulated to the actuator in the region of a corner thereof.

[0014] The axis of the joint connecting the head plate to the first arm and the axis of the joint connecting the head plate to the second arm are further preferably arranged in a plane parallel to the horizontal or parallel to the plane of the head plate.

[0015] According to a further preferred embodiment, the first arm and the second arm are arranged parallel to one another, so that together with the actuator and the head plate, an offset kinematics designed as a parallelogram is obtained.

[0016] According to a particularly preferred embodiment, the head plate is pivotally mounted. If the bucket assembly is pivoted 90°, the wheel loader cannot move laterally toward a rack because the wheels cannot be steered 90° to the side. The pivotally mounted offset kinematics makes it possible to remove a pallet from a rack positioned parallel to the direction of travel.

[0017] In particular, the lifting cylinder and / or the offset cylinder are designed as hydraulic cylinders. Specifically, when the lifting cylinder and the offset cylinder are designed as hydraulic cylinders, the piston chamber of the lifting cylinder communicates with the piston chamber of the offset cylinder, and the rod chamber of the lifting cylinder communicates with the rod chamber of the offset cylinder. Since the offset cylinder pulls (and does not push) the lifting frame in the working direction, the oil displaced by the lifting cylinder (during the lifting process) can be used to initiate the pulling movement of the offset kinematics. This occurs by displacing the hydraulic oil from the large chamber of the lifting cylinder into the large chamber of the offset cylinder, and the hydraulic oil from the small chamber of the lifting cylinder into the small chamber of the offset cylinder.This preferred embodiment makes it possible to control the lifting and offset cylinders simultaneously and to design a simple operation for the wheel loader driver.

[0018] Finally, it is advantageous if the offset cylinder is designed to cause an offset of the lifting frame in the working direction when it is shortened.

[0019] A fork or a shovel is the preferred attachment.

[0020] The invention will be explained in more detail below with reference to a particularly preferred embodiment shown in the accompanying drawings. They show: Fig. 1 shows a schematic side view of a particularly preferred wheel loader of the invention; Fig. 2 shows a front view of a particularly preferred wheel loader with a laterally pivoted lifting frame in a raised first position (A) and in a lowered second position (B); and Fig. 3 shows a detailed view of the components forming the offset kinematics in a first position (A) and in a second position (B) with the lifting frame offset in the working direction.

[0021] Fig. 1 shows a schematic side view of a particularly preferred wheel loader of the invention.

[0022] In particular, Fig. 1 a wheel loader 10 with a lifting frame 20 extending in a working direction, at the free end of which an attachment 30 in the form of a fork is arranged. The lifting frame 20 is articulated to a lifting cylinder 40 so that the lifting frame 20 and thus the attachment 30 can be raised and lowered. The wheel loader 10 has a rotatably mounted head plate 50 with a first arm 60 articulated to the head plate 50, the free end of which is connected to an offset cylinder 70 articulated to the head plate 50. The end of the lifting frame 20 opposite the attachment 30 is articulated to the free end of the first arm 60, and the lifting cylinder 40 is articulated to an actuator 80 at its other end.The actuator, in turn, is articulated on the one hand to the free end of the first arm 60 and on the other hand to the free end of a second arm 90 articulated to the head plate 50, so that a change in the length of the offset cylinder 70 causes an offset of the lifting frame 20 in the plane of the working direction of the attachment 30. In particular, it can be seen that when the offset cylinder 70 is shortened, it causes an offset of the lifting frame 20 forward in the working direction.

[0023] Fig. 2 shows a front view of a particularly preferred wheel loader with a laterally pivoted lifting frame in a raised first position (A) and in a lowered second position (B). In particular, Fig. 2 It is evident that if all hydraulic cylinders are controlled electronically, a pallet can be transported vertically upwards, as is otherwise only possible with a forklift truck, since the forward movement of the attachment (due to the circular arc that the lifting frame 20 describes when lifting) is compensated by the folding mechanism of the offset kinematics.

[0024] This is also Fig. 3 This is clearly evident in the figure, which shows a detailed view of the components forming the offset kinematics in a first position (A) and in a second position (B) displacing the lifting frame 20 in the working direction. The double offset cylinder 70 moves the mechanism more or less horizontally, with the parallelogram being designed to minimize vertical movement.

[0025] Since the offset cylinders 70 pull (and not push) the lifting frame 20 in the working direction, the design allows the hydraulic oil displaced by the lifting cylinder 40 during the lifting process to be used for the pulling movement of the offset cylinder 70. The hydraulic oil is displaced from the piston chamber of the lifting cylinder 40 into the piston chamber of the offset cylinder 70, and the hydraulic oil is displaced from the rod chamber of the lifting cylinder 20 into the rod chamber of the offset cylinder 70. This design enables a uniform lifting process combined with a forward movement of the lifting frame 20 or a uniform lowering combined with a backward movement of the lifting frame 20.

[0026] Finally, in Fig. 3 It can be seen that the first arm 60 in the starting position, i.e. in the retracted position of the lifting frame 20, leans against a stop which limits the movement of the lifting frame 20 against the working direction.

Claims

1. wheel loader (10) having a lifting frame (20) extending in a working direction, an attachment (30) arranged at the free end of the lifting frame (20) and a lifting cylinder (40) connected at its one end in an articulated manner to the lifting frame (20), a head plate (50) being connected to a first arm (60) which is attached in an articulated manner to the head plate (50) and whose free end is connected to an offset cylinder (70) attached in an articulated manner to the head plate (50), wherein - the end of the lifting frame (20) opposite the attachment (30) is connected in an articulated manner to the free end of the first arm (60), and - the lifting cylinder (40) is hingedly connected at its other end to an actuator (80) which is hingedly connected on the one hand to the free end of the first arm (60) and on the other hand to the free end of a second arm (90) hingedly connected to the head plate (50), so that a change in length of the displacement cylinder (70) causes a displacement of the lifting frame (20) in the plane of the working direction, characterised in that the actuator (80) is triangular in shape, the first arm (60), the second arm (90) and the lifting cylinder (40) each being connected to the actuator (80) in an articulated manner in the region of a corner of the latter.

2. wheel loader (10) according to claim 1, characterised in that the lifting frame (20), the first arm (60) and the offset cylinder (70) form a common joint with a common axis of rotation.

3. wheel loader (10) according to one of the preceding claims, characterised in that the axis of the joint connecting the head plate (50) to the first arm (60) and the axis of the joint connecting the head plate (50) to the second arm (90) are arranged in a plane parallel to the head plate (50).

4. wheel loader (10) according to one of the preceding claims, characterised in that the first arm (60) and the second arm (90) are arranged parallel to each other.

5. wheel loader (10) according to one of the preceding claims, characterised in that the head plate (50) is rotatably mounted.

6. wheel loader (10) according to one of the preceding claims, characterised in that the lift cylinder (40) and / or the offset cylinder (70) are hydraulic cylinders.

7. wheel loader (10) according to claim 6, characterised in that the piston chamber of the lift cylinder (40) is connected in a communicating manner to the piston chamber of the offset cylinder (70) and the rod chamber of the lift cylinder (40) is connected in a communicating manner to the rod chamber of the offset cylinder (70).

8. wheel loader (10) according to one of the preceding claims, characterised in that the offset cylinder (70) is set up to effect an offset of the lifting frame (20) in the working direction when it is shortened.

9. wheel loader (10) according to one of the preceding claims, characterised in that the attachment (30) is a fork or a shovel.