CN110809657A

CN110809657A - Vertical lifting device for construction machine

Info

Publication number: CN110809657A
Application number: CN201880044220.0A
Authority: CN
Inventors: E·瓦格纳; 赵云峰
Original assignee: Guangxi Liugong Machinery Co Ltd
Current assignee: Guangxi Liugong Machinery Co Ltd
Priority date: 2018-01-26
Filing date: 2018-11-23
Publication date: 2020-02-18
Also published as: US20200370269A1; EP3610079A1; WO2019144688A1; EP3610079A4

Abstract

A lifting device for a construction machine (optionally a loader), wherein the construction machine has a frame arrangement with a front frame part (30) and a rear frame part (20); the lifting device is mountable to the front frame part (30) and comprises: a main arm (3) provided with a pivot connector (4) at a proximal end thereof and an equipment connector (5) at a distal end thereof; a main arm support means (6) for pivotably supporting the pivot connector (4) of the main arm (3), wherein the main arm support means (6) is movable in a direction including at least a component in a front-rear direction with respect to the frame means; wherein the lifting device is configured to: pivoting the main arm (3) between a lowered position and a raised position, causing the device connector (5) to follow a substantially vertical path; the lifting device further comprises a tilting device (400) for tilting the device (15) mounted on the device connector (5) of the main arm (3), the tilting device (400) comprising a kinematic chain (406) for connecting to the tilting connector (151) of the device (15) mounted on the device connector (5) of the main arm (3).

Description

Vertical lifting device for construction machine

Technical Field

The present invention relates to a lifting device for a construction machine, the lifting device comprising: a main arm provided with a pivot connector at a proximal end thereof and an equipment connector at a distal end thereof; and a main arm supporting device for pivotably supporting the pivot connector of the main arm. The work machine may be a loader, optionally a wheel loader. The lifting device is configured to: pivoting the main arm between the lowered position and the raised position causes the device connector to follow a substantially vertical path. The lifting device further comprises a tilting device for tilting the device connected to the device connector of the main arm. The apparatus may be a bucket.

Background

A vertical lift loader is a construction machine that includes a front frame section and a rear frame section that are hingedly interconnected to provide articulated steering. Such loaders include a lift device that is supported by the front frame portion of the hinged frame arrangement and is hinged with the front frame portion relative to the rear frame portion when turned.

The lift mechanism of the vertical lift loader allows an implement (e.g., a bucket) to move between a lowered position and a raised position. These vertical lifting devices are characterized by a movement pattern of the equipment between the lowered position and the raised position following a substantially vertical path. This shortens the maximum distance from the bucket center of mass to the front axle of the loader, thereby increasing the maximum loading capacity while maintaining the vehicle weight.

The lifting device of such a vertical lift loader usually comprises a tilting device for tilting the equipment, which tilting device is connected to the lifting device. A known tilting device for a vertical lift loader is a Z-bar type device. In these devices, the operating lever is supported by the main arm in an articulated manner, wherein the upper end of the operating lever (lever) is connected to the tilt cylinder and the lower end of the operating lever is connected to the tilt link. The inclined oil cylinder is arranged above the main arm, and the inclined connecting rod transversely penetrates from the lower end of the operating rod below the main arm to the inclined connector of the equipment above the main arm. By actuating the tilt cylinder, the tilting movement of the device can be initiated by means of the operating lever and the tilt link.

The disadvantages of these known vertical lifting devices are: their inherent nature limits the maximum loading capacity.

Disclosure of Invention

It is therefore an object of the present invention to provide a vertical lifting device with a tilting device, thereby increasing loading capacity.

The invention is based on the following idea: for a given vehicle weight, the maximum load capacity of the vertical lift device is primarily determined by the distance between the bucket center of mass and the front axle of the vehicle. The distance may be affected by the amount of tilt of the bucket, as tilt affects the position of the center of mass of the bucket. Furthermore, the position of the bucket center of mass at the lowering position of the hoist is critical to the path of travel of the implement, as it will set an anchor point for the minimum distance of the bucket center of mass from the front axle of the loader. Thus, in the lowered position, the bucket should be tilted as far as possible towards the construction machine so that its centre of mass is close to the front axle of the axle.

However, the Z-bar type tilting device limits the bucket rollback to the lowered position due to interference of the tilting links of the tilting device with the front axle and the front wheel of the construction machine, respectively. This is mainly because the greater rollback of the bucket means a greater deflection of the lower end of the operating lever of the tilting device towards the front axle and the front wheels, respectively.

The present invention utilizes this concept in the following way: in a first aspect, there is provided a lifting device for a construction machine having a frame arrangement with a front frame portion and a rear frame portion; the lifting device may be mounted to the front frame portion. The work machine may be a loader, such as a wheel loader. The lifting device comprises: a main arm provided with a pivot connector at a proximal end thereof and an equipment connector at a distal end thereof; a main arm supporting device for pivotably supporting the pivot connector of the main arm; wherein the main arm support means is movable in a direction comprising at least a component in a front-to-back direction with respect to the frame means.

The lifting device is configured to: pivoting the main arm between the lowered position and the raised position causes the device connector to follow a substantially vertical path. In the context of the present invention, the lowered position is preferably the lowest position of the appliance connector in normal operating conditions of the lifting device. Further, preferably, the raised position of the equipment connector is the highest position of the equipment connector under normal operating conditions of the lifting device. Further, the substantially vertical path is a path having verticality in consideration of the current context. The path may deviate slightly from a strictly vertical path but without affecting its substantial verticality. The generally vertical path may be a J-shaped path, wherein the device connector moves upwardly and forwardly from a lowered position to a raised position, and then moves substantially only linearly upwardly. However, the path may also be a strictly vertical path.

Further, the lifting device further includes a tilting device for tilting the device mounted on the device connector of the main arm. The apparatus may be a bucket. However, other types of equipment may also be used in this regard. The tilting means includes a kinematic chain for connecting to a tilting connector of a device mounted on the device connector of the main arm; a tilt actuator; and a connector for connecting the kinematic chain and the tilt actuator. In the lowered position of the main arm, the kinematic chain is located above the main arm and the tilt actuator is located below the main arm. The kinematic chain comprises a tilting link and a connecting rod which are pivotably connected to each other. By the above configuration, a so-called reverse Z-shape of the reclining device is achieved. In the context of the present invention, this means that the tilting link does not extend below the main arm, so that there is no risk of the tilting link interfering with the front axle and the front wheels, respectively, of the construction machine in all normal operating conditions of the lifting device. Preferably, the entire tilting link is located above the main arm in the lowered position. Furthermore, the kinematic chain (i.e. the tilting link and the connecting rod) may be located above the main arm under all normal operating conditions of the lifting device. Since the moving chain includes the tilting link and the connecting rod pivotably connected to each other, the apparatus can be tilted by retracting the tilting actuator to the raised position without collision between the main arm and the moving chain. To further enhance this effect, the tilt link may also be made up of multiple parts.

In the context of the present invention, directional terms refer to the case where the lifting device is mounted to the construction machine.

According to the invention, the lifting device is configured to: the tilting device does not limit the bucket rollback in the lowered position of the lifting device. This is achieved by providing a kinematic chain connectable to the device above the main arm, thereby preventing interference of the kinematic chain and the front axle. Thus, in the lowered position, the bucket center of mass may be closer to the front axle of the work machine than in the prior art, thereby increasing the maximum loading capacity while maintaining the vehicle weight. The lifting device according to the invention can thus utilize its full loading capacity potential by including a tilting device as above. The tilting device according to the invention thus exhibits a synergistic effect with the vertical lifting device.

According to an embodiment of the lifting device, the connector is a lever pivotably supported by the main arm. The joystick includes an upper connector disposed above the main arm and a lower connector disposed below the main arm. The operating lever may be supported in the upper half of the main arm in the length direction of the main arm. Further, a distance from the upper connector of the joystick to the joystick support may be greater than a distance from the lower connector of the joystick to the joystick support. This embodiment allows a compact arrangement of the lifting device. Furthermore, the operating lever allows a transmission ratio to be achieved in the tilting device of the lifting device.

According to an embodiment of the lifting device, the tilt link connects the tilt connector of the apparatus to a connecting rod, which is connected to the upper connector of the joystick. In the lowered position of the lifting device, the kinematic chain is arranged completely above the main arm. Alternatively, the kinematic chain is arranged completely above the main arm in all normal operating conditions of the lifting device. The advantages of this embodiment are: the entire tilting device can be placed above the main arm up to the position of the joystick so that it is completely removed from the area around the front axle to allow a larger bucket rollback in the lowered position.

According to an embodiment of the lifting device, the tilting device may comprise a guide link. One end of the guide link is pivotally supported by the main arm, and the other end is pivotally supported by the link. The guide link allows a large tilting force to be transmitted to the device via the kinematic chain, since it guides the tilting force introduced into the kinematic chain into the tilting direction.

According to an embodiment of the lifting device, the guide link is pivotably connected to the tilt link. The kinematic chain may also comprise more than two links.

According to an embodiment of the lifting device, the lifting device further comprises an apparatus, wherein the apparatus is a bucket. The bucket includes: a main arm connector connected to the main arm; and a tilt connector connected to a tilt link of the tilting device of the lifting device. The tilt connector of the bucket is located above the main arm connector.

Further, the tilt actuator of the lifting apparatus according to the embodiment of the present invention may include a tilt cylinder for driving the tilting movement of the device connected to the main arm. However, the tilt actuator is not limited to a cylinder, and may be, for example, a motor that drives a lead screw. The tilt actuator is coupled to the tilt link. However, the coupling cannot be a direct coupling, but a plurality of components may be provided between the tilt cylinder and the tilt link. Preferably, the tilt cylinder is located below the main arm under all normal operating conditions of the lift. The embodiment has the advantages that: a very compact lifting device can be provided.

The tilt cylinder may be connected to the lower connector of the operating lever. This embodiment means that the joystick can be used to transmit tilting forces from the tilt cylinder to the device. This embodiment has a high flexibility since the joystick can achieve a transmission ratio. Furthermore, the first part of the tilting means located below the main arm is the tilting cylinder, which however, from the point of view of the device, is located upstream of the operating lever and thus outside the region of the front axle. Thus, the present embodiment allows for the use of a joystick in the tilting device, which has advantages while not affecting the bucket rollback of the lowering position of the lifting device.

According to an embodiment of the lifting device, the tilt cylinder may be connected to the front frame part of the frame device. In other words, one end of the tilt cylinder may be connected to the front frame part of the frame arrangement. Preferably, the other end of the tilt cylinder is connected to a lower connector of the operating lever. This embodiment allows a relatively light design of the main arm and the main arm support means, since the tilt cylinder is supported by the frame means of the construction machine.

According to another embodiment of the lifting device, the tilt cylinder is connected to the main arm support. In other words, one end of the tilt cylinder may be connected to the main arm supporting device. Preferably, the other end of the tilt cylinder is connected to a lower connector of the operating lever. The embodiment has the advantages that: it is convenient to mount the lifting device on the construction machine because the tilt cylinder must be mounted on the construction machine without fail.

The lifting device according to an embodiment of the present invention further includes a guide device engaged with the main arm at a guide portion of the main arm located between the pivot connector and the device connector, wherein the guide device guides the main arm such that the device connector follows a substantially vertical path when the main arm is pivoted between the lowered position and the raised position. Preferably, the guide means may be connected to the front frame portion of the frame means. The guide means provide a relatively simple mechanical way of implementing the vertical lifting device.

The lifting device according to the embodiment of the present invention further includes: a main arm actuating element engaged with the main arm; an auxiliary actuating element engaged with the main arm supporting device to move the device connector between a lowered position and a raised position; determining means for determining a lift-related quantity reflecting a position of the appliance connector relative to the front frame means; control means for controlling the operation of the main arm actuating element and the auxiliary actuating element based on the determined elevation-related quantity so that a path when the device connector moves between the lowered position and the raised position follows a substantially vertical path. The main arm actuating element, the auxiliary actuating element, the determining means, and the control means for controlling the actuating element based on the output of the determining means may use a vertical lift device.

In a second aspect, the present disclosure is directed to a construction machine, optionally a loader, having an articulated frame arrangement of a front frame portion and a rear frame portion, the front frame portion and the rear frame portion being hingedly interconnected to provide articulated steering; construction machine comprising a lifting device according to any of the preceding claims. The loader may be a wheel loader. Furthermore, the lifting device may be supported by the front frame part of the articulated frame arrangement such that the lifting device is articulated together with the front frame part relative to the rear frame part upon steering. With regard to the advantages of the construction machine according to the second aspect, it is referred to the above-mentioned advantages in relation to the lifting device.

Drawings

Fig. 1 shows a construction machine equipped with a vertical lifting device according to a first embodiment in a lowered position;

fig. 2 shows the construction machine equipped with the vertical lifting device according to the first embodiment in an intermediate position;

fig. 3 shows the construction machine equipped with the vertical lifting device according to the first embodiment in a raised position;

fig. 4 illustrates a first embodiment of a tilting device of a vertical lifting device of a construction machine according to the first embodiment in a perspective view;

FIG. 5 shows the tilting device of FIG. 4 in a side view in a lowered position;

FIG. 6 schematically shows the tilting device of FIG. 4 in a side view in a raised position;

fig. 7 illustrates a second embodiment of a tilting device of a vertical lifting device of a construction machine according to the first embodiment in a perspective view;

FIG. 8 shows the tilting device shown in FIG. 7 in a side view;

fig. 9 shows a construction machine equipped with a vertical lifting device according to a second embodiment in a lowered position;

fig. 10 shows a construction machine equipped with a vertical lifting device according to a second embodiment in an intermediate position;

fig. 11 shows the construction machine equipped with the vertical lifting device according to the second embodiment in a raised position;

figure 12 shows the components of a control system applied to a lifting device according to a second embodiment;

fig. 13 shows a third embodiment of a tilting device of a vertical lifting device of a construction machine according to the first and second embodiments in a perspective view.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. It should be noted that the embodiments discussed below may be combined with each other, and the present invention is not particularly limited to the specific embodiments and modified structures and devices discussed below.

General overview

The present invention relates to a lifting device including a tilting device generally applicable to construction machines. The following embodiments show and explain the lifting device as a construction machine structure, wherein the construction machine is embodied as a wheel loader. However, the specific application of the lifting device according to the invention is not limited to the application of a wheel loader. Rather, the lifting device according to the invention may be applied to any type of drivable work machine, such as a loader having wheels or a track chain or even a combination of both. Further, the type of steering is not limited to the alternative articulated steering arrangement discussed below. On the contrary, the lifting device is applicable to a construction machine having any type of steering device, such as an articulated steering device, a skid steering device, or any other type.

A construction machine to which the lifting device according to the present invention can be applied will be briefly described based on the illustration of fig. 1. Fig. 1 shows a construction machine 1 in a simplified side view. Elements not essential to the present invention are omitted. Fig. 1 does not show a tilting device of a lifting device of a construction machine. Fig. 4 to 7 show an embodiment of a tilting device of a construction machine.

The construction machine 1 includes a front frame portion 30 and a rear frame portion 20. In the example according to fig. 1, a pair of front wheels 301 is mounted on the front frame part 30 and a pair of rear wheels 201 is mounted on the rear frame part 20. The front frame portion 30 is mounted to the rear frame portion 20 by an articulated steering arrangement 40. Articulated steering gear 40 is well known to the skilled person and comprises one or more supports for providing an articulated mounting between front frame part 30 and rear frame part 20 by means of a pivot arranged substantially along a vertical axis of work machine 1, i.e. perpendicular to the longitudinal direction of work machine 1. The articulated steering device 40 provides tilting between the front frame part 30 and the rear frame part 20 to provide steering by varying the angle between the axis of rotation of the front wheels 301 and the axis of rotation of the rear wheels 201. The articulated steering device 40 may be driven by an actuator (e.g., a hydraulic actuator) not shown. The type and construction of the articulated steering apparatus 40 is not essential to the invention and may be adjusted as desired.

The construction machine 1 in the example shown in fig. 1 includes an operator cab 203 mounted on the rear frame portion 20. Within the operator's cab 203, space for an operator is provided, as well as required operating and control elements (not shown) that may be used by the operator. The operator's cab 203 includes a window, not shown, to provide visibility of the surrounding area to the operator.

An engine compartment 202 is provided on the rear frame portion 20, which houses one or more power sources to provide the power required to operate the work machine 1. These power sources may include, but are not limited to, internal combustion engines (e.g., diesel engines) that may be connected to other devices (e.g., hydraulic pumps, generators, etc.). The power source is used to provide power to drive the front wheels 301 and/or the rear wheels 201 and to power actuators, among other elements of the construction machine.

The front frame portion 30 extends forward relative to the rear frame portion 20. In this example, the front frame portion 30 is located forward of the operator's cab 203 and the engine compartment 202. However, the application of the lifting device according to the present invention is not limited to the construction machine 1 having such a device.

During a steering operation, the front frame portion 30 is tilted with respect to the rear frame portion 20, the operator's cab 203, and the engine compartment 202. However, it is also possible to provide a modified steering device, such as a single wheel steering device, a front wheel steering device or a rear wheel steering device, while the articulated steering device may be omitted or provided merely as an option.

The following three embodiments will explain a lifting device according to the present invention, in which the lifting device is mounted to the front frame portion 30 of the above-described exemplary construction machine 1 embodied as a wheel loader.

First embodiment

A lifting device according to a first embodiment will now be described with reference to fig. 4 to 6. The lifting device comprises a main arm 3 provided with a pivot connector 4 at its proximal end and a device connector 5 at its distal end. The pivot connector 4 is pivotably supported on a main arm supporting means 6, which in this embodiment includes a main arm supporting link 6 a. The main arm support link 6a has a first end 12 and a second end 13, wherein the first end 12 is pivotably connected to the pivot connector 4 of the main arm 3 and the second end 13 is pivotably connected to an element of the front frame portion 30. The connection between the pivot connector 4 of the main arm 3 and the first end 12 of the main arm support link 6a may be provided as a suitable type of bearing means to provide sliding rotation of the main arm 3 relative to the main arm support link 6 a.

The second end 13 of the main arm support link 6a is pivotally mounted on the front frame portion 30. In order to pivotally mount the main arm support link 6a to the front frame portion 30, a suitable type of rotational bearing is arranged for providing pivotable movement of the main arm support link 6a relative to the front frame portion 30.

The arrangement of the main arm support link 6a is such that the rotational or pivotal motion of the main arm support link 6a provides movement of the first end 12 in a direction including at least a component in the forward-backward direction of the construction machine 1. Therefore, in the case shown in fig. 1, the main arm support link 6a is directed upward at a certain inclination angle with respect to the vertical direction.

The main arm 3 includes a guide portion 10 provided between the pivot connector 4 and the device connector 5. In the present embodiment, the guide portion 10 is also offset by a predetermined amount from the line connecting the pivot connector 4 and the device connector 5. However, the offset is not required for the present invention, but is a preferred arrangement.

The lifting device according to the invention further comprises a guide means 7, which in the embodiment shown in fig. 1 comprises a guide arm 7a having a first end 8 and a second end 9. The first end 8 is pivotally mounted to the front frame portion 30 and the second end 9 is pivotally mounted to the main arm 3 of the guide portion 10. The second end 9 is pivotally mounted to a suitable type of bearing provided in the region of the guide portion 10 of the main arm 3 so as to provide pivotable movement relative to the guide arm 7a of the main arm 3. On the other hand, the first end 8 is pivotally mounted to the tag frame portion with a suitable type of bearing to provide pivotable movement relative to the guide arm 7a of the front frame portion.

An actuator 11 is provided in the lifting device. The first end 11b of the actuator is pivotally mounted to the front frame part 30 and the second end 11a is pivotally mounted to the main arm 3. In the present embodiment, the actuator is embodied as a linear actuator, such as a hydraulic actuator, but not limited thereto. The distance between the first end 11b and the second end 11a may be varied when operating the actuator 11, for example by introducing pressurized liquid into a pressure chamber of the actuator 11.

A bucket 15 is provided on the implement coupler 5 of the main arm 3, and an implement that can be attached to the main arm is described by way of example. The bucket includes a main arm connector for connecting to the equipment connector 5 of the main arm 3 and a tilt connector 151 for tiltably operating the bucket. The tilt connector 151 is disposed above the main arm connector. The tilting means for the first embodiment of the tilting bucket 15 are not shown in fig. 1-3 and will be described in further detail below.

In the exemplary arrangement shown in fig. 1, the guide arm 7a is directed rearward with respect to the first end 8 of the guide arm 7 a. In fig. 1, the position of the lifting device shown is defined as the lowered position, in which the bucket is in the lowermost position, in which the bucket is able to receive the material to be lifted and to contact the ground. However, if desired, a range of elevation extending below the ground baseline may be provided.

The operation of the lifting device according to the invention will be explained in detail below on the basis of the illustrations of fig. 1-3.

Fig. 1 shows the lifting device in a lowered position. In this case, the main arm is rotated downward as shown in fig. 1. This is achieved by retracting the actuator 11, which is used to operate the main arm 3. The position of the main arm 3 depends on the link between the guide arm 7a and the main arm support link 6 a. In other words, the position of the pivotal connector 4 of the main arm 3 can be changed by changing the rotational position of the main arm support link 6a, while the guide arm 7a, due to its rotational connection between the front frame part 30 and the guide part 10 of the main arm 3, makes it possible to determine the position of the pivotal connector 4 according to the rotational position of the main arm 3. Thus, the lifting device provides a link-based transmission that determines only the position of the main arm 3.

When the actuator 11 is actuated, the main arm 3 rotates clockwise in fig. 1. By this rotation, the main arm 3 rotates with respect to the main arm support link 6 a. At the same time, the guide arm 7a rotates in the counterclockwise direction. When the guide arm 7a is rotated in the counter-clockwise direction, the guide portion 10 of the main arm 3 is forced along a circular path due to the constant distance between the first end 8 and the second end 9 of the guide arm 7 a. The circular path provided by the rotation of the guide arm 7a bulges towards the main arm support means, which in this example comprises a main arm support link 6 a.

Fig. 2 shows the lifting device of fig. 1 in an intermediate position, which is raised a predetermined amount from the lowered position. It can be seen that the guide arm 7a is rotated in a counter-clockwise direction from the position shown in figure 1. In this case, the position of the second end 9 of the guide arm 7a moves with respect to the rearward movement component of the work machine 1. In the same case, the main arm 3 rotates in the clockwise direction, and the bucket 15 mounted on the equipment connector rises by a predetermined amount. Since the guide portion 10 of the main arm 3 is urged rearward by the predetermined moving path of the second end 9 of the guide arm 7a, the main arm support link 6a rotates in the clockwise direction about the second end 13 thereof mounted on the front frame portion 30. Therefore, the position of the first end 12 of the main arm support link 6a moves rearward together with the pivot connector 4 of the main arm 3 with respect to the construction machine.

Upon further operation of the actuator 11, the main arm 3 is further rotated in the clockwise direction and reaches the raised position shown in fig. 3. In this position, the bucket 15 attached to the implement coupler 5 of the main arm 3 reaches a position higher than the intermediate position shown in fig. 2. The position is the highest raised position of the bucket 15, which can be achieved by the embodiment shown in fig. 1-3. When the main arm 3 is further rotated in the clockwise direction, the guide arm 7a is further rotated in the counterclockwise direction, and the guide portion 10 of the main arm 3 is further rotated along the circular path. When the second end 9 of the guide arm 7a moves forward relative to the position shown in fig. 2, the main arm support link 6a rotates in the counterclockwise direction from the position shown in fig. 2. Therefore, the position of the first end 12 of the pivot connector 4 supporting the main arm 3 is further forward than the position shown in fig. 2.

Based on the above operation, the bucket 15 can be moved from the lowered position shown in fig. 1 to the raised position shown in fig. 3 via the intermediate position shown in fig. 2. Based on the inventive arrangement comprising the guide arm 7a and the main arm support link 6a, the device connector 5 is forced along a predetermined movement path, which is shown in the figure as path P. In this illustration, path P forms an S-shape, but follows a substantially vertical path throughout the movement of the device connector from the lowermost position to the uppermost position. The substantially vertical path may be a J-shaped path. In particular, the path P deviates from a circular path, which can be achieved by prior art lifting devices, wherein the pivot connector 4 of the main arm 3 is immovable and fixed with respect to the frame part of the construction machine 1. According to the invention, the movement of the pivot connector 4 of the main arm is achieved by providing movable support means 6 and guide means 7 which bring the main arm 3 into a specified movement pattern, thus forming a substantially vertical movement range of the device connector 5.

Further, the lifting device according to the first embodiment further includes a tilting device 400 for tilting the bucket 15 connected to the implement connector 115 of the main arm 3. Fig. 4-5 illustrate a first embodiment of a tilting device 400. The tilting device 400 includes a lever 401 pivotably supported by the main arm 3. Specifically, the main arm 3 includes a pivot connector 402 for supporting the joystick 401. A pivot connector 402 may be provided at the connector 403, which extends between two parallel main arm brackets. The connector 403 may be disposed in the middle of the main arm length extension. Preferably, a pivot connector 402 for supporting the joystick 401 is provided at the upper end of the connecting piece 403, i.e. the end facing the wheel loader. In a preferred embodiment, the pivot connector 402 may be provided in the upper half of the length extension of the main arm 3.

The joystick 401 includes a lower connector 404 located below the main arm 3 and an upper connector 405 located above the main arm 3. Preferably, the distance from the upper connector 405 of the joystick 401 to the pivot connector 402 for supporting the main arm 3 is greater than the distance from the lower connector 404 to the pivot connector 402. Thus, joystick 401 according to the preferred embodiment has a gear ratio. In other words, a relatively small movement path and a relatively large force of the lower connector 404 may result in a relatively large movement path and a relatively small force of the upper connector 405 due to the different distances from the upper connector 405 and the lower connector 404 to the pivot connector 402 for supporting the joystick 401.

Furthermore, the tilting means 400 comprise a kinematic chain 406. The kinematic chain 406 is connected to the upper connector 405 of the joystick 401 and to the tilt connector 151 of the bucket 15. Thus, the kinematic chain 406 transmits the movement of the upper connector 405 of the joystick 401 to the tilt connector 151 of the bucket 15. In this embodiment, the kinematic chain 406 comprises a tilting link 407 and a connecting rod 408 which are pivotably connected to each other. The length of the connecting rod 408 may be more than twice the length of the tilt link 407. The tilt link 407 is also connected to the tilt connector 151 of the bucket 15. The connecting rod 408 is also connected to the upper connector 405 of the joystick 401. The complete kinematic chain 406 is arranged above the main arm 3. In particular, the kinematic chain 406 never extends to the region below the main arm 3 under all normal operating conditions of the lifting device. There is therefore no risk of interference between the tilting link 407/kinematic chain 406 and the front axle of the construction machine and the front wheel 301. Therefore, the tilting device 400 according to the present embodiment does not restrict the bucket rollback under any normal operating conditions of the lifting device, because the tilting device is disposed above the main arm 3.

Further, the tilting device 400 according to the present embodiment includes a guide link 409. The guide link 409 is pivotably supported by the main arm and the inclined link 407 of the kinematic chain 406. The guide link 409 ensures a specific movement pattern of the tilting connector 151, thereby allowing a large tilting force. The guide link 409 may be supported at a lower end of the link 403 of the main arm 3, i.e., an end facing away from the construction machine.

Furthermore, the tilting device 400 comprises a tilting cylinder 410 for driving the tilting movement of the bucket 15. The tilt cylinder 410 is connected to the lower connector 404 of the operating lever 401 and extends from the lower connector 404 toward the construction machine. In the present embodiment, the tilt cylinder 410 is disposed entirely below the main arm 3. Further, in the present embodiment, the tilt cylinder 410 is connected to the front frame portion 30 of the articulated frame device. Therefore, the main arm 3 and the main arm support 6 do not have to carry the weight of the tilt cylinder 410 when the bucket 15 moves between the lowered position and the raised position.

To tilt the bucket 15, the tilt cylinder 410 is actuated to move the lower connector 404 of the joystick 401 connected thereto. Movement of the lower connector 404 causes the joystick 401 to rotate about the pivot connector 402, which moves the upper connector 405 of the joystick in a direction opposite to the direction in which the lower connector 404 is moved. The movement of the upper coupler 405 is transferred to the tilt coupler 151 of the bucket 15 through the kinematic chain 406, thereby tilting the bucket 15. Such interference can be prevented, since all parts of the tilting means 400, which may interfere mainly with the front axle and/or the front wheels 301 of the wheel loader, are located above the main arm 3. Thus, the tilting device of the lifting device according to the present embodiment does not limit the bucket rollback in any normal operating state of the wheel loader, in particular not in the lowered position.

As shown in fig. 6, since the kinematic chain 406 includes the tilt link 407 and the connecting rod 408 pivotably connected to each other by the kinematic chain connector 411, the bucket 15 can be tilted by retracting the tilt cylinder 410 to the raised position. By retracting the tilt cylinder 410 to the raised position, the kinematic chain connector 411 will move upward away from the main arm 3, thereby avoiding collision of the kinematic chain 406 with the main arm 3.

Second embodiment

Fig. 7-8 show a lifting device according to a second embodiment. The lifting device according to the second embodiment comprises a tilting device 400 substantially provided according to the first embodiment, so only the differences between these embodiments will be outlined below.

The configuration of the tilting device 400 according to the second embodiment is the same as that of the first embodiment except for the following: the tilt cylinder 410 is not connected to the front frame portion 30 of the articulated steering apparatus, but is connected to the main arm support 6. This facilitates mounting of the lifting device to the front frame part, since the tilt cylinder 410 does not have to be connected to the front frame part 30 of the wheel loader.

Now, a lifting device and a lifting process thereof according to a second embodiment will be described in detail with reference to fig. 9 to 12. The lifting device according to the second embodiment is configured as the lifting device of the first embodiment described above, except for the differences outlined below, and therefore the description about the lifting process also applies to the first embodiment.

An auxiliary actuating element 21 embodied as a linear actuator is provided in the lifting device according to the second embodiment. The auxiliary actuating element 21 has a first end 21a and a second end 21b, the first end 21a being pivotably mounted to the main arm support link 6a in the embodiment shown in fig. 9. The second end 21b of the auxiliary actuating element 21 is pivotably mounted to the main arm 3. The purpose of the auxiliary actuating element 21 is therefore to vary the inclination angle between the main arm support link 6a and the main arm 3. In other words, by extending the auxiliary actuating element 21, the angle between the main arm support link 6a and the main arm 3 increases.

By driving the main arm actuating element 11, the main arm 3 rotates about the pivot center provided on the second bearing portion 13 of the main arm support link 6 a. In other words, by extending the main arm actuating element 21, the main arm 3 is rotated in the clockwise direction together with the main arm support link 6a, thereby achieving the lifting operation.

Referring to fig. 12, there is disclosed a control system element for a lifting device in accordance with a second embodiment of the present invention. The control system shown is an example only and elements not essential to the invention are not shown in the figure. The control system shown in fig. 12 is installed at a suitable position in the construction machine. The basic element of the control system is a control device 60, which includes a CPU for performing control operations and other calculations required to operate the control system. Information can be obtained from the determination means 50 for determining the amount of lifting related reflecting the position of the device connector 5 relative to the front frame part 30. The determination means 50 may comprise sensors 51, 52, 51A, 52A. The sensors may be embodied as sensors 51, 52 which provide relevant information for the extended position of the linear actuators for the primary 11 and secondary 21 actuator elements. Such sensors are well known to the skilled person and will be appropriately selected from the available types. Alternatively, the rotation sensor may be mounted to a lifting device element that undergoes relative rotation of two elements, such as the connection between the pivot connector 4 of the main arm 3 and the first bearing portion 12 of the main arm support link 6a, or a bearing portion of the front frame portion 30 that supports the first bearing portion 12 of the main arm support link 6 a. The sensor type can be selected as desired as long as it can provide information of the relative position of the main arm with respect to the main arm support link 6a and the relative position of the main arm support link 6a with respect to the front frame portion 30. The determination device 50 using the above-described sensor transmits the electric signal to the control device 60, and then is further processed by the CPU as shown below.

The CPU of the control device 60 communicates with the storage device 63 and is capable of retrieving information from the storage device and transferring information to the storage device 63. The storage means 63 comprise, among other information, a set of information in the form of data, such as functions or modes.

Further, the input section 61 communicates with the control device 60. The input portion 61 is capable of transmitting a signal to the control device 60, which is triggered by an operator operating the work machine, for example. Alternatively or additionally, the input portion 61 may further communicate with other control systems to provide an automatic trigger for transmitting a signal to the control device 60.

The control device 60 communicates with an output section 63 for controlling the drive system of the lifting device, in particular the main arm actuating element 11 and the auxiliary actuating element 21. The output portion 63 may be coupled to a solenoid portion (not shown) for controlling the pressure and/or flow rate of hydraulic fluid into and out of the actuator pressure chamber in a known manner. Thus, the output section 62 can convert the signal provided by the control device 60 into the actuating movements of the main arm actuating element 11 and the auxiliary actuating element 21.

The above-mentioned functions or modes contained in the storage means 63 are used to control the movement mode of the appliance connector 5 of the lifting device during the lifting operation. According to the present embodiment, the control system provides a relationship between the movement of the main arm actuating element 11 and the movement of the auxiliary actuating element 21. In other words, the function or mode contained in the storage device 63 includes the relationship between the operating position of the main arm actuating element and the operating position of the auxiliary actuating element 21. This relationship may be continuous (continuous).

The operation of the lifting device based on the control is explained as follows. Starting from the state in fig. 9, the operator manipulates an operation element (not shown) associated with the input portion 61 to initiate a lifting operation to raise the appliance connector 5 from the lowered position shown in fig. 9 to the raised position shown in fig. 11 via the intermediate position shown in fig. 10. By the lifting device shown in fig. 9, the main arm actuator element 11 is extended to turn the main arm 3 and the main arm support link 6a in the clockwise direction in the drawing. During operation of the main arm actuating element 11, the auxiliary actuating element 21 is retracted, as shown by a comparison of fig. 9 and 10. Upon such retraction of the auxiliary actuating element 21, the angle between the main arm 3 and the main arm support link 6a decreases and the pivot connector 4 retracts backwards with respect to the frame device.

After further performing the lifting operation from the intermediate position shown in fig. 10, the main arm actuator element 11 is further expanded to further rotate the main arm 3 in the clockwise direction in the drawing. During the lifting operation between the intermediate position shown in fig. 10 to the raised position shown in fig. 11, the auxiliary actuator element 21 is extended again to increase the angle between the main arm 3 and the main arm support link 6 a. In this way the pivot connector 4 will move forward relative to the frame arrangement.

The above-described fitting is to combine the main arm actuator element 11 and the auxiliary actuator element 21 with the configuration using the main arm support link 6a, based on which the movement pattern of the device connector 5 can be provided which deviates from a circular path having a constant radius.

The above-described resulting movement pattern, which can be derived from fig. 9-11, is achieved by using closed loop control, with the signal from the sensor as an input and the signal from the output section 62 as an output. Starting again from the state in fig. 9, the determination device 50 using sensors continuously determines the extended positions of the main arm actuating element 11 and the auxiliary actuating element 21 on the premise that linear sensors are used. By starting the raising and lowering operation, the sensor that determines the extended position of the main arm actuator element 11 senses a predetermined extension and sends it as a signal to the control device 60. The control means will use the signal and continuously compare the obtained signal with the currently selected function or mode of the memory means. The function may be provided as a continuous function defining the relationship between the extended position of the main arm actuating element 11 and the extended position of the auxiliary actuating element 21, such that the comparison generates a unique output of the target extended position of the auxiliary actuating element 21. The output section 62 will control the solenoid section to set the position of the auxiliary actuating element 21 to a position corresponding to the target position obtained from the pattern in the memory means.

The above-described closed-loop control is continuously performed by the control system so that there is always a unique relationship between the extended position of the main arm actuating element 11 and the extended position of the auxiliary actuating element 21. According to the present embodiment, as described above, a mode or function can be set so that the movement mode of the device connector can be predetermined in various ways.

Based on the above operation, the bucket 15 shown in fig. 9 can be moved from the lowered position shown in fig. 9 to the raised position shown in fig. 11 via the intermediate position shown in fig. 10. Based on the control system and the means, the movement of the device connector 5 is controlled by the control system along a predetermined movement path, which is shown in the figure as path P. In this illustration, path P is S-shaped, but follows a substantially vertical path throughout the movement of the device connector from the lowered position to the raised position. In particular, the path P deviates from a circular path, which can be achieved by prior art lifting devices, wherein the pivot connector 4 of the main arm 3 is immovable and fixed with respect to the frame part of the construction machine 1 and the device connector 5 is fixed with respect to the main arm 3. According to the present embodiment, in addition to the control system discussed above, the movement of the pivot connector 4 of the main arm can be achieved by providing the movable main arm support 6 and the auxiliary actuating element 21 so that the main arm 3 moves in a specified movement pattern, thereby achieving a substantially vertical movement range of the device connector 5.

The lifting device according to the second embodiment further comprises a tilting device 400, which is not shown in fig. 9-11. In conjunction with the lifting device of the first embodiment, the tilting device 400 is constructed according to the first or second embodiment of the tilting device 400.

Third embodiment

Now, a lifting device according to a third embodiment will be described in detail with reference to fig. 13. Fig. 13 shows a lifting device according to a third embodiment, in which the left side is in the lowered position and the right side is in the raised position.

The lifting device according to the third embodiment is configured as the lifting device of the first and second embodiments described above, except for the differences outlined below. Therefore, the description about the above-described elevating process (see the second embodiment) is also applicable to the third embodiment.

The third embodiment is different from the second embodiment in that: a short self-leveling link 412 and a long self-leveling link 413 are added. The short leveling link 412 is connected to the main arm support link 6 and is connected to both the long leveling link 413 and the tilt cylinder 410. The long leveling link 413 is connected to the front frame portion 30 and is connected to both the short leveling link 412 and the tilt cylinder 410.

Claims

1. A lifting device for a construction machine, optionally a loader, having a frame arrangement with a front frame part (30) and a rear frame part (20), the lifting device being mountable to the front frame part (30), the lifting device comprising

A main arm (3) provided with a pivot connector (4) at its proximal end and an equipment connector (5) at its distal end,

a main arm support means (6) for pivotably supporting the pivot connector (4) of the main arm (3), wherein the main arm support means (6) is movable in a direction comprising at least a component in a front-to-back direction with respect to the frame means,

wherein the lifting device is configured to cause the device connector (5) to follow a substantially vertical path when pivoting the main arm (3) between a lowered position and a raised position,

the lifting device further comprises a tilting device (400) for tilting a device (15) mounted to the device connector (5) of the main arm (3), the tilting device (400) comprising: a kinematic chain (406), said kinematic chain (406) being intended to be connected to a tilting connector (151) of said device (15), said device (15) being mounted on a device connector (5) of said main arm (3); a tilt actuator (410); and a connector (401), the connector (401) connecting the kinematic chain (406) and the tilt actuator (410),

wherein the content of the first and second substances,

in the lowered position of the main arm (3), the kinematic chain (406) is located above the main arm (3), the tilting actuator is located below the main arm (3),

wherein the content of the first and second substances,

the kinematic chain (406) comprises a tilting link (407) and a connecting rod (408) which are pivotably connected to each other.

2. The lifting device according to claim 1, wherein the connector is a lever (401) pivotably supported by the main arm (3), the lever (401) comprising an upper connector (405) disposed above the main arm (3) and a lower connector (404) disposed below the main arm (3).

3. Lifting device according to claim 2, wherein the tilting link (407) connects a tilting connector (151) of the apparatus (15) to the connecting rod (408), the connecting rod (408) being connected to an upper connector (405) of the joystick (401).

4. The lifting device according to claim 3, wherein the tilting device (400) further comprises a guide link (409), the guide link (409) being pivotably supported at one end by the main arm (3) and at the other end by the kinematic chain (406).

5. A lifting device according to claim 4, wherein the guide link (409) is pivotably connected to a tilting link (407) of the kinematic chain (406).

6. A lifting device according to any of the preceding claims, further comprising an apparatus (15), wherein the apparatus (5) is a bucket, the apparatus (5) comprising: a main arm connector connected to a device connector (5) of the main arm (3); and a tilt connector (151), the tilt connector (151) being connected to a tilt link (407) of the tilt device (400), the tilt connector (151) being located above the main arm connector.

7. A lifting device according to any of the preceding claims, wherein the tilt actuator comprises a tilt cylinder (410), the tilt cylinder (410) being adapted to drive a tilting movement of a device (15) connected to the device connector (5) of the main arm (3).

8. A lifting device according to claim 7, wherein the tilt cylinder (410) is located below the main arm (3) in all normal operating conditions of the lifting device.

9. A lifting device according to claim 7 or 8 when dependent directly or indirectly on claim 2, wherein the tilt cylinder (410) is connected to a lower connector (404) of the operating lever (401).

10. A lifting device according to claim 7, 8 or 9, wherein the tilt cylinder (410) is connectable to the front frame part (30) of the frame device or to the main arm support device (6).

11. A lifting device according to any of the preceding claims, further comprising a first self-leveling linkage (412) and a second self-leveling linkage (413) longer than the first self-leveling linkage (412), wherein the first self-leveling linkage (412) is connected to the main arm support (6) and to both the second self-leveling linkage (413) and the tilt actuator (410); and the second self leveling link (413) is connected to the front frame portion (30) and to both the first self leveling link (412) and the tilt actuator (410).

12. A lifting device according to any of the preceding claims, further comprising a guiding means (7), the guiding means (7) being engaged with the main arm (3) at a guiding portion thereof, the guiding portion of the main arm being located between the pivot connector (4) and the device connector (5), wherein the guiding means (7) guides the main arm (3) such that the device connector (5) follows a substantially vertical path when pivoting the main arm (3) between the lowered position and the raised position.

13. The lifting device according to any one of claims 1 to 12, further comprising: a main arm actuating element (11) engaged with said main arm (3), and an auxiliary actuating element engaged with said main arm support means (6) for moving said device connector (5) between said lowered position and said raised position; -determination means (50) for determining a lifting-related quantity reflecting the position of the device connector (5) relative to the front frame part (30); and a control device (60), the control device (60) being configured to control the operation of the main arm actuator element (11) and the auxiliary actuator element (21) based on the determined elevation-related quantity such that a path of the device connector (5) when moving between the lowered position and the raised position follows a substantially vertical path.

14. A construction machine (1), optionally a loader, wherein the construction machine has an articulated frame arrangement of a front frame part (30) and a rear frame part (20), which are interconnected in an articulated manner to provide articulated steering, comprising a lifting arrangement according to any of the preceding claims.

15. A construction machine (1) according to claim 14, wherein said lifting device is supported by a front frame part (30) of said articulated frame arrangement and is articulated with said front frame part (30) with respect to said rear frame part (20) when turning.