Pull-along vehicle and method of operating the same

Abstract

A hooklift truck and its operating method are disclosed. The hooklift truck includes a frame for receiving containers, a boom pivotally movable relative to the frame, a linear actuator disposed between the frame and the boom, the linear actuator being actuated to pivot the boom, the boom including a hook having a hook body defining an opening for hooking a container, and the hook including a latch configured to lock to close the hook opening or unlock to open the hook opening. The method includes: receiving an inclination parameter relating to the boom's inclination; and controlling the latch of the hook based on the inclination parameter to lock or unlock.

Description

Technical Field

[0001] This invention relates to a method for operating a hooklift truck and to a hooklift truck itself. Specifically, this invention relates to the control of the locking mechanism on the hook of the hooklift truck. Background Technology

[0002] Hook-lift trucks typically include hooks for attaching to and picking up containers. Hooks usually include latches for opening and closing them. Opening and closing the hooks is typically done manually by the operator or by gravity. However, this can lead to the latches unlocking if it causes inconvenience or poses a hazard. Summary of the Invention

[0003] According to a first aspect, a method for operating a boom lift is provided, the boom lift including a frame for receiving containers, a boom pivotally movable relative to the frame, a linear actuator disposed between the frame and the boom, the linear actuator being actuated to pivot the boom, the boom including a hook having a hook body defining an opening for hooking a container, the hook including a latch configured to lock to close the hook opening or unlock to open the hook opening, the method comprising: receiving an inclination parameter relating to the inclination of the boom; and controlling the latch of the hook based on the inclination parameter to lock or unlock.

[0004] The control of the bolt can be automatic and does not require manual intervention.

[0005] The bolt lock can be controlled by actuating the bolt lock actuator. Controlling the bolt lock can include controlling the extension or retraction of the bolt lock actuator or controlling the rotation of the bolt lock actuator.

[0006] Locking actuators can include linear actuators or rotary actuators. Locking actuators can be single-acting actuators. Single-acting linear or rotary actuators can have a biasing mechanism configured to bias the actuator in the retraction direction (i.e., the direction opposite to the actuation direction), for example, a single-acting spring-return pneumatic actuator.

[0007] The tilt parameter can be received from a tilt switch mounted on the boom, configured to output a digital signal. The tilt parameter can also be received from a tilt sensor mounted on the boom. The tilt parameter can be a first tilt parameter, and the method can include receiving a second tilt parameter relating to the frame tilt. The first tilt parameter can be calibrated based on the second tilt parameter to identify the tilt of the boom relative to the frame.

[0008] The inclination parameter can be received from an inductive sensor mounted on the chassis. The inclination parameter can also be received from an extension degree sensor in the linear actuator, configured to output a signal representing the extension degree of the linear actuator.

[0009] Linear actuators can be hydraulic cylinders.

[0010] Controlling the locking or unlocking of the latch may include controlling a valve located in a first fluid line between the latch actuator and a pressure fluid source, based on the slope parameter. A manual button may be provided, which, when activated, manually controls the latch unlocking by supplying pressure fluid to the latch actuator, wherein the supply of pressure fluid to the latch is achieved by controlling the valve to open, or by other means, such as through a fluid line different from the valve.

[0011] According to a second aspect, a hooklift truck is provided, comprising: a frame for receiving a container; a boom pivotally coupled to the frame, a linear actuator disposed between the frame and the boom, the linear actuator being actuable to pivot the boom, the boom including a hook having a hook body defining an opening for hooking a container, the hook including a latch configured to lock to close the hook opening and unlock to open the hook opening; a sensor configured to generate an inclination parameter relating to the boom inclination; and a controller configured to operate the hooklift truck using the method according to the first aspect.

[0012] The hook may include a bolt actuator configured to extend and retract to control the bolt locking or unlocking.

[0013] The bolt can be elongated and pivotally coupled to the hook body in its central portion. The bolt can be pivotally attached to a bolt actuator at a first end, while the second end of the bolt can be configured to close the opening of the hook, such that extension of the bolt actuator causes the bolt to unlock, and retraction of the bolt actuator causes the bolt to lock.

[0014] The hook may include a bolt actuator configured to rotate to control the bolt locking or unlocking.

[0015] The hooklift truck may include a tilt switch mounted on the boom, configured to generate the tilt parameter. The hooklift truck may include an inductive sensor mounted on the frame, configured to generate the tilt parameter. The hooklift truck may include an extension degree sensor mounted in the linear actuator, configured to output a signal representing the extension degree of the linear actuator to generate the tilt parameter.

[0016] The hooklift truck may include a tilt sensor mounted on the boom, configured to generate the tilt parameter.

[0017] The controller can be configured to control the hooklift truck using the method according to the first aspect, wherein the tilt sensor can be a first inclinometer configured to generate a first tilt parameter. The hooklift truck can include a second inclinometer mounted on the frame and configured to generate a second tilt parameter relating to the inclination of the frame.

[0018] The hooklift truck may include a fluid circuit comprising a valve disposed in a first fluid line between a pressure fluid source and a latching actuator. The valve may be controlled by a controller to selectively allow fluid to flow from the pressure fluid source through the first fluid line to the latching actuator. The valve may be a solenoid valve. The fluid circuit may include a second fluid line parallel to the first fluid line and including a push-button valve disposed between the pressure fluid source and the latching actuator. The push-button valve may be actuated to allow fluid to flow from the pressure fluid source through the second fluid line to the latching actuator. A shuttle valve may be disposed at the point where the first and second fluid lines meet, selectively allowing fluid to flow through either the first or second fluid line to the latching actuator at any given time.

[0019] This invention may include any combination of the various features and / or limitations mentioned herein, unless such features are mutually exclusive. Attached Figure Description

[0020] The invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0021] Figure 1 and Figure 2 The first exemplary hooklift truck is schematically shown, which is arranged to pick up a container;

[0022] Figure 3a A second exemplary hooklift truck is shown schematically;

[0023] Figure 3b The third exemplary hooklift truck is shown schematically;

[0024] Figure 3c The fourth exemplary hooklift truck is shown schematically;

[0025] Figure 4a and Figure 4b An exemplary hook for a hooklift truck is shown schematically;

[0026] Figure 5 An exemplary fluid circuit diagram for controlling the hook bolt is shown; and

[0027] Figure 6 A flowchart illustrating the steps of operating a boom lift truck. Detailed Implementation

[0028] Figure 1 and 2 The diagram schematically shows a side view of a hook-lift truck (hook-type loader) 10 and a container 12 to be picked up by the hook-lift truck 10. Figure 1 In the middle, the hooklift truck 10 is in the pickup mode, Figure 2 The medium-lift boom truck 10 is in loading mode.

[0029] The hooklift truck 10 includes a frame 14 for receiving containers 12, and a cab 16 located at the front of the frame 14 (shown as the left side in the figure). Figure 1 In the middle, container 12 is located on the rear side frame 14 (shown as the right side in the figure). Figure 2 In this process, container 12 is loaded onto frame 14; in other words, container 12 is received on frame 14.

[0030] The hooklift truck 10 also includes a boom 18, which is pivotable relative to the frame 14 in a pickup position (as shown in...). Figure 1 ) and loading location (as shown in Figure 2 Between. In this example, the upper arm 18 includes a first segment and a second segment orthogonal to the first segment (i.e., a right-angle arm). In some examples, the upper arm may be a hinged upper arm.

[0031] A linear actuator 20 is arranged between the boom 18 and the frame 14 and is actuated to pivot the boom 18 between a loading position and a pickup position. In this example, the linear actuator 20 is a hydraulic cylinder. It will be understood that in other examples, any suitable linear actuator may be used to pivot the boom.

[0032] In the loading position, the first section of the boom 18 is parallel to the frame 14, so that the container 12 can be received on the first section in the loading position. In the pick-up position, the first section is pivoted from the loading position toward the rear of the frame 14, so that the second section extends beyond the rear of the frame 14.

[0033] The boom 18 includes a hook 22, which includes a hook body 23 defining an opening 26 for hooking a container 12. The container includes a rod 24, and the hook 22 is configured to receive the rod 24 to hold the container 12. The hook 22 also includes a latch 28 configured to close the opening 26 of the hook body 23 by locking, or to open the opening 26 of the hook body 23 by unlocking. A mechanism for this purpose will be described in reference to... Figure 4a and Figure 4b More detailed description.

[0034] In the picking mode, as shown in Figure 1 The linear actuator 20 extends fully, causing the boom 18 to pivot toward the rear of the frame 14, and the hook 22 to align with or be hooked onto the rod 24 of the container 12. In the loading configuration, as shown... Figure 2The linear actuator 20 retracts completely, thus the boom 18 is stored in the frame 14, and the hook 22 is close to the cab 16 (i.e., close to the front of the frame 14). With the container's lever 24 held in the hook 22, movement of the boom 18 from the pick-up position to the loading position causes the container 12 to be loaded onto the frame 14 of the hooklift truck 10. With the container 12 loaded onto the frame 14, movement of the boom 18 from the loading position to the pick-up position causes the container 12 to be unloaded from the frame 14.

[0035] exist Figure 1 In the middle, the bolt 28 is unlocked, causing the opening 26 of the hook body 23 to open, while Figure 2 In this configuration, the latch 28 is locked, thus closing the opening 26 of the hook body 23. Closing the opening 26 of the hook body 23 ensures that the container 12 will not be accidentally released from the hook 22.

[0036] In this example, the boom lift 10 also includes a sensor 30 configured to generate inclination parameters related to the inclination of the boom 18. In this example, sensor 30 is a tilt switch disposed on the boom 18. In other examples, the sensor may be a tilt sensor disposed on the boom.

[0037] The hooklift truck 10 includes a controller 32 configured to automatically control the locking and unlocking of the latch 28 of the hook 22 during loading and unloading of the container 12, thereby controlling the closure of the opening 26 of the hook body 23. Importantly, the hook 22 is locked at an optimal angle at the boom 18 during loading and unloading of the container 12 to ensure that the container 12 does not accidentally detach from the hook 22. The optimal angle may vary for different hooklift trucks. Automatic locking of the latch 28, without manual intervention, improves the safety of the hooklift truck 10.

[0038] Controller 32 is configured to receive signals in the form of slope parameters from sensor 30 and control bolt 28 to automatically lock or unlock based on these slope parameters, as shown in reference. Figure 5 More detailed description.

[0039] Figure 3a A second exemplary hooklift truck 100 is shown. Figure 3b A third exemplary hooklift truck 200 is shown. Figure 3c A fourth exemplary hooklift truck 300 is shown. The second, third, and fourth exemplary hooklift trucks 100, 200, and 300 are similar to the first exemplary hooklift truck 10, differing only in the inclusion of different sensor configurations configured to generate inclination parameters related to the inclination of the boom 18.

[0040] exist Figure 3aIn this example, the hooklift truck 100 includes a first tilt sensor 40 mounted on the boom 18 and configured to generate a first tilt parameter relating to the tilt of the boom 18. The second exemplary hooklift truck 100 also includes a second tilt sensor 42 mounted on the frame 14 and configured to generate a second tilt parameter relating to the tilt of the frame 14. The first tilt parameter can therefore be calibrated using the second tilt parameter to determine the tilt of the boom 18 relative to the frame 14. Using the tilt of the boom 18 relative to the frame 14 to control the locking and unlocking of the hook 22 means that the hooklift truck 100 can be reliably used on sloping ground.

[0041] exist Figure 3b In the third exemplary boom lift 200, an extension degree sensor 50 is mounted in a linear actuator 20 and configured to output a signal representing the extension of the linear actuator 20 to generate an inclination parameter relating to the inclination of the boom 18 relative to the frame 14.

[0042] exist Figure 3c In the case of the boom lift 300, an inductive sensor 60 is mounted on the frame 14. The inductive sensor 60 is configured to generate a signal representing the distance between a portion of the boom 18 and the frame 14, thereby generating a slope parameter relating to the slope of the boom 18 relative to the frame 14.

[0043] Figure 4a and Figure 4b The hook 22 of the exemplary hooklift trucks 10, 100, 200, and 300 is shown in more detail. Figure 4a The hook 22 is shown to be in the unlocked state. Figure 4b The hook 22 is shown in the locked state.

[0044] The hook body 23 includes a curved section with a recessed geometry to define a hook section 25 and an opening 26. In this example, the latch 28 is elongated and includes a hook end 28a extending from a pivot point 72 and an actuating end 28b extending from the pivot point 72 in the opposite direction to the hook end 28a, such that the pivot point 72 is located in the central portion of the latch 28. The latch 28 is pivotally coupled to the hook body 23 at the pivot point 72. The hook end 28a is configured to selectively open and close the opening 26 of the hook body 23 to unlock and lock the latch 28, respectively. The hook end 28a is arranged inside the hook section 25 of the hook body 23, so that it can pivot within the hook section 25.

[0045] Hook 22 includes a latching actuator 80 disposed in a hole 27 in hook body 23, configured to control the latch 28 of hook 22 to lock or unlock (i.e., correspondingly close or open opening 26). In this example, latching actuator 80 is a linear actuator pivotally attached to the actuating end 28b of latch 28 and hook body 23. Latching actuator 80 is configured to extend or retract to control the locking or unlocking of latch 28. In other examples, the latching actuator may be a rotary actuator configured to rotate to control the locking or unlocking of the latch.

[0046] In this example, retraction of the latch actuator 80 causes the latch 28 to pivot, thereby locking the latch 28 to close the opening 26, with the hook end 28a abutting the inner surface of the hook section 25 of the hook body 23. Extension of the latch actuator 80 causes the latch 28 to pivot, thereby pivoting the hook end 28a inward within the hook section 25 of the hook body 23, thereby unlocking the latch 28 and opening the opening 26 of the hook body 23.

[0047] Understandably, in other examples, the hook end of the latch may be configured to abut against the outer surface of the hook segment of the hook body and pivot away from the hook body to achieve unlocking. In some examples, extension of the latch actuator may cause the latch to lock, and retraction of the latch actuator may cause the latch to unlock. In other examples, the latch may be elongated and pivotally attached to the hook body such that only one end extends from the pivot point, to which the latch actuator is pivotally attached to control the locking or unlocking of the latch.

[0048] Figure 5 An exemplary fluid circuit 600 is shown for controlling the latching actuator 80 of hooklift trucks 10, 100, 200, and 300, in this example being a single-acting latching actuator 602. In this example, the single-acting latching actuator 602 is a linear single-acting spring-return cylinder. It includes a spring configured to bias the actuator in the retraction direction (i.e., bias in the direction opposite to the actuation direction). It will be understood that in other examples, the single-acting actuator may be a rotary actuator, or any suitable biasing mechanism or force may be provided to bias the actuator in a certain direction. In a further example, the latching actuator may be a double-acting actuator.

[0049] The single-acting latch actuator 602 simplifies the control of the latch 28 because, in this example, the single-acting latch actuator 602 is biased to the retracted position (i.e., the latch 28 is biased to lock), and the solenoid valve only needs to be activated to unlock the latch 28 by controlling the extension of the single-acting latch actuator 602. Furthermore, in the event of a failure of the solenoid valve 606, the hook 22 fails and remains locked due to the bias of the single-acting latch actuator 602 to the retracted position, and due to the configuration of the latch actuator 80 and the latch 28, which locks the latch 28 when the latch actuator 80 retracts. This makes the use of the hooklift trucks 10, 100, 200, and 300 safer.

[0050] The fluid circuit 600 includes a pressure source 604 fluidly connected to a single-acting latching actuator 602 via a first fluid line 610 and a second fluid line 612 parallel to the first fluid line 610. The pressure source 604 is configured to supply pressurized fluid to the single-acting latching actuator 602. The fluid circuit 600 also includes a solenoid valve 606 fluidly disposed on the first fluid line 610 between the pressure source 604 and the single-acting latching actuator 602. The solenoid valve 606 is configured to selectively allow fluid to flow from the pressure source 604 to the single-acting latching actuator 602 via the first fluid line 610. The opening and closing of the solenoid valve is controlled by a controller 32.

[0051] The fluid circuit 600 also includes a manual push-button valve 608, which fluidly connects to a second fluid line 612 between the pressure source 604 and the single-acting latch actuator 602. The manual push-button valve 608 is configured to selectively allow fluid to flow from the pressure source 604 to the single-acting latch actuator 602 via the second fluid line 612 and is manually actuated by an operator.

[0052] A manual push-button valve 608 is provided on a second fluid line 612 parallel to the first fluid line 610, allowing manual bypass operation of the fluid circuit 600 to unlock the latch 28. This may be useful when a malfunction in the solenoid valve 606 or controller 32 prevents the automatic control of the solenoid valve 606 from extending to unlock the latch 28 via the single-acting latch actuator 602.

[0053] A shuttle valve 614 is positioned at the point where the first fluid line 610 and the second fluid line 612 meet. The shuttle valve 614 is thus positioned between the solenoid valve 606 and the single-acting latching actuator 602, and between the manual push-button valve 608 and the single-acting latching actuator 602. The shuttle valve 614 allows fluid from one of the two sources, namely, fluid from the first fluid line 610 or the second fluid line 612, to flow through it.

[0054] The control of solenoid valve 606 will be discussed later. Figure 6A more detailed description follows. It is understood that in some examples, automatic control of a single-acting latching actuator can be achieved without the second fluid line 612 and the push-button valve.

[0055] Figure 6 The flowchart illustrates a method 700 for operating the boom lifts 10, 100, 200, and 300.

[0056] In block 702 of method 700, a slope parameter relating to the inclination of boom 18 is received. In this example, the slope parameter is received from a tilt switch 30 mounted on boom 18. In this example, tilt switch 30 is configured to output a digital signal.

[0057] In block 704, controller 32 determines whether latch 28 should be unlocked based on the received inclination parameter. In this example, the inclination parameter is provided by tilt switch 30, which outputs a LOW or HIGH signal. The tilt switch can be calibrated to output a LOW signal between -45° and a threshold α°, and a HIGH signal between the threshold α° and 315°, where the 0° line 85 (best shown in...) Figure 1 The angle is parallel to the frame 14 along the direction from the rear to the front (i.e., from the right to the left in the figure). The angle from the 0° line 85 in the clockwise direction is a positive angle, and the angle from the 0° line 85 in the counterclockwise direction is a negative angle.

[0058] In this example, controller 32 is configured to determine that latch 28 should be unlocked upon receiving a HIGH signal and to determine that latch 28 should be locked upon receiving a LOW signal. If the controller determines that the latch should be unlocked, the method proceeds to block 706, where solenoid valve 606 is opened, latch 28 is unlocked, and pressurized fluid is supplied to single-acting latch actuator 602 to extend and unlock latch 28. The method then returns to block 702 to restart.

[0059] In other examples, a controller may not be necessary. As an example, a tilt switch that outputs a digital signal can directly control the opening or closing of a solenoid valve based on its output.

[0060] If the controller determines that the latch 28 should not be unlocked (i.e., the latch 28 should be locked), the method proceeds to block 708 to lock the latch 28 by controlling the solenoid valve 606 to close.

[0061] Simultaneously with blocks 702-708, block 710 determines whether manual button 608 has been activated. If manual button 608 is determined to be activated, the method proceeds to block 706 to unlock the bolt. This is thus used as a cascading control to unlock bolt 28, regardless of the slope parameters, by allowing pressurized fluid to flow through the second fluid line 612 to the single-acting bolt actuator 602.

[0062] In this example, the second fluid line 612 is manually opened by activating the manual button 608, allowing pressurized fluid to be supplied from the pressure source 604 through the second fluid line 612 to the single-acting latch actuator 602 to unlock the latch. In other examples, the manual button can send a cascading control signal to a controller to control a solenoid valve or other valve in the second fluid line to unlock the latch.

[0063] If manual button 608 is not activated, the method proceeds to box 708, where latch 28 is locked. In this example, at box 708, controller 32 controls solenoid valve 606 to close, preventing further pressurized fluid from being supplied to the single-acting latch actuator 602 via solenoid valve 606. This allows the single-acting latch actuator 602 to retract via a spring, locking latch 28. Once latch 28 is locked at box 708, the method returns to box 702 to restart.

[0064] In this example, method 700 has two pathways to unlock the latch 28, such that the system is always waiting for a signal to unlock the latch 28 from either the manual button 608 or the tilt parameter. When no signal to unlock the latch 28 is received, the solenoid valve remains closed. Although method 700 is described as receiving the tilt parameter from a tilt switch, it is understood that the method can also be implemented by receiving tilt parameters related to the tilt of the boom 18 from any suitable sensor. In some examples, where the tilt parameter is provided by a sensor, such as a tilt meter, an inductive sensor, or an extension degree sensor, the received tilt parameter can be compared to a threshold, and the controller can control the latch unlocking based on the comparison with the threshold. In a further example, where the sensor is a tilt meter on the boom, the tilt parameter can be calibrated by a second tilt meter on the frame before being received by the controller and compared with the threshold.

Claims

1. A method of operating a reach truck, the reach truck comprising a carriage for receiving a container, a jib pivotably coupled to the carriage, a linear actuator disposed between the carriage and the jib, the linear actuator actuatable to pivot the jib, the jib comprising a hook having a hook body defining an opening for hooking the container, the hook comprising a latch configured to lock to close the opening of the hook or to unlock to open the opening of the hook, the method comprising: receiving a tilt parameter relating to a tilt of the jib; and controlling the latch of the hook to lock or unlock based on the tilt parameter; wherein the tilt parameter is a first tilt parameter and the method comprises receiving a second tilt parameter relating to a tilt of the carriage and the first tilt parameter is calibrated based on the second tilt parameter to identify the tilt of the jib relative to the carriage.

2. The method of claim 1, wherein, The latch is controlled by actuation of a latch actuator.

3. The method of claim 2, wherein, The controlling of the latch comprises controlling the latch actuator to extend or retract or controlling the latch actuator to rotate.

4. The method of any one of claims 1-3, wherein, The first tilt parameter is received from a tilt switch mounted on the jib, the tilt switch configured to output a digital signal.

5. The method of any one of claims 1-3, wherein, The first tilt parameter is received from a tilt sensor mounted on the jib.

6. The method of any one of claims 1-3, wherein, The first tilt parameter is received from an inductive sensor mounted to the carriage or the first tilt parameter is received from an extension level sensor in the linear actuator, the extension level sensor configured to output a signal representative of an extension level of the linear actuator.

7. The method of any one of claims 1-3, wherein, The linear actuator is a hydraulic cylinder.

8. A reach truck comprising: a carriage for receiving a container; a jib pivotably coupled to the carriage, a linear actuator disposed between the carriage and the jib, the linear actuator actuatable to pivot the jib, the jib comprising a hook having a hook body defining an opening for hooking the container, the hook comprising a latch configured to lock to close the opening of the hook and to unlock to open the opening of the hook; a sensor configured to generate a tilt parameter relating to a tilt of the jib; and a controller configured to operate the reach truck using a method according to any one of claims 1-7.

9. The sled of claim 8, wherein, The hook comprises a latch actuator configured to extend and retract to control the latch to lock or unlock.

10. The sled of claim 9, wherein, The latch is elongate and pivotably coupled to the hook body in a central portion of the latch and the latch is pivotably attached to the latch actuator at a first end of the latch and a second end of the latch is configured to close the opening of the hook such that extension of the latch actuator causes the latch to unlock and retraction of the latch actuator causes the latch to lock.

11. The sled of claim 8, wherein, The hook comprises a latch actuator configured to rotate to control the latch to lock or unlock.

12. The reach truck of any one of claims 8-11 comprising a tilt switch mounted on the jib and configured to generate the first tilt parameter or comprising an inductive sensor mounted to the carriage and configured to generate the first tilt parameter or comprising an extension level sensor mounted in the linear actuator and configured to output a signal representative of an extension level of the linear actuator to generate the first tilt parameter.

13. The trailer as claimed in any one of claims 8-11, comprising a tilt sensor mounted on the jib and configured to generate the first inclination parameter.

14. The sled of claim 13, wherein, The tilt sensor is a first inclinometer configured to generate the first inclination parameter, and the trailer comprises a second inclinometer mounted on the frame and configured to generate a second inclination parameter relating to the inclination of the frame.

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