JP6206998B1 - Forklift cargo handling equipment - Google Patents

Abstract

A forklift cargo handling device with higher operability is provided. When the operating lever is operated from the neutral position to the operating zone, the higher the operating speed of the operating lever in the dead zone, the easier it is to adjust the lever characteristics at higher speeds. As the operation speed in the dead zone is smaller, a lever characteristic that allows easier speed adjustment at a low speed is set. Then, when the operating lever is reversed toward the neutral position, it is determined whether to maintain the lever characteristic or switch to another lever characteristic based on the command amount to the hydraulic drive means at that time. [Selection] Figure 4

Description

  The present invention relates to a cargo handling device for a forklift for operating a cargo handling tool.

  A forklift is provided with a cargo handling device for cargo handling work. The cargo handling apparatus includes a fork that supports a workpiece, a hydraulic drive unit that causes the fork to lift, tilt, reach, and the like, an operation lever that is operated by an operator for the operation of the fork, and the like. The hydraulic drive means includes a hydraulic circuit, a hydraulic motor, a proportional solenoid valve, a hydraulic cylinder, and the like.

  The forklift stores a lever characteristic that defines a command amount to the hydraulic drive means with respect to a tilt angle from the neutral position of the operation lever. The command amount to the hydraulic drive means is, for example, a command torque of the hydraulic motor, an exciting current of the proportional solenoid valve (amount of opening of the proportional solenoid valve), and the like. The lever characteristic has the characteristic that the command amount increases in proportion to the tilt angle, that is, the operation speed of the fork increases in proportion to the tilt angle. When the operation lever is operated, the command amount is determined from the tilt angle at that time in accordance with the set lever characteristics. The hydraulic drive means is driven and controlled with the determined command amount.

  As disclosed in Patent Literatures 1-3, a plurality of lever characteristics having different characteristics are stored in the forklift. Each lever characteristic has advantages and disadvantages. For example, one lever characteristic is easy to adjust the speed of the fork at a low speed but difficult to adjust the speed at a high speed, and another lever characteristic is difficult to adjust the speed of the fork at a low speed. The speed adjustment is easy to adjust.

  The operator sets one lever characteristic from the plurality of lever characteristics and operates the fork. For example, in Patent Documents 2 and 3, a button or a switch is provided in the driver's seat of the forklift, and an appropriate lever characteristic can be set in advance by using the button or the switch before operating the operation lever.

  In Patent Document 1, an appropriate lever characteristic is automatically set based on the speed of the operation lever when the operation lever is tilted from the neutral position. According to this configuration, the burden of button operation or switch operation disclosed in Patent Documents 2 and 3 is reduced.

  According to the embodiment of Patent Document 1, once the lever characteristic is set, the set lever characteristic is maintained until the operation lever is returned to the neutral position. That is, the fork is operated according to the same lever characteristics when the operation lever is tilted from the neutral position (when the fork is accelerated) and when it is returned to the neutral position (when the fork is decelerated). According to this configuration, it is possible to provide the operator with the optimum operability when the operation lever is tilted from the neutral position, but it is not always possible to provide the operator with the optimum operability when returning the operation lever to the neutral position. Absent.

  According to the additional embodiment of Patent Document 1, after the operating lever is tilted from the neutral position and the lever characteristic is set, when the operating lever is reversed to the neutral position, a new lever characteristic is set at the time of the reversal. The That is, the fork is operated according to different lever characteristics depending on whether the operation lever is tilted from the neutral position or returned to the neutral position. However, setting a new lever characteristic when the operation lever is reversed may not be preferable depending on the operation state of the operator.

JP 2001-199695 A JP 2002-274895 A JP 2014-159321 A

  The present invention provides a forklift loading / unloading device with higher operability.

The present invention relates to a cargo handling device for a forklift, and the cargo handling device operates a cargo handling tool, an operation lever for operating the cargo handling tool, and hydraulically operates the cargo handling tool when the operation lever is operated. Hydraulic drive means for operating, an operation amount detecting means for detecting an operation amount from a neutral position of the operation lever, and an operation speed detecting means for detecting an operation speed of the operation lever,
Of the operating range of the operating lever, a predetermined range including the neutral position is a dead zone in which the cargo handling equipment is not operated even when the operating lever is operated, and the operating lever is operated in a range exceeding the dead zone. And an operation band in which the cargo handling equipment is operated,
Characteristic storage means for storing a first main lever characteristic to an nth main lever characteristic in which a command amount to the hydraulic drive means with respect to the operation amount in the operation band is determined (n is a natural number of 2 or more);
Each of the first main lever characteristic to the n-th main lever characteristic has a characteristic that the command amount increases in proportion to the operation amount, and the change with respect to a change in the operation amount in a range where the operation amount is small. The change rate of the command amount is such that the (k-1) main lever characteristic is smaller than the kth main lever property, and the change rate in the range where the operation amount is large is the kth main lever property It is smaller than the (k-1) th main lever characteristic (k is a natural number satisfying 2 ≦ k ≦ n),
The main lever has a smaller rate of change in a larger range of operation as the operation speed in the dead zone is larger when the operation lever is operated from the neutral position to the operation zone beyond the dead zone. A forklift cargo handling device having characteristics set,
In the case where the operation speed in the dead zone is less than a predetermined value,
When the command amount at the time of reversal as the command amount at the time of reversing toward the neutral position of the operation lever is less than a predetermined value, the set main lever characteristic is maintained,
When the reversal command amount is greater than or equal to a predetermined value, a first sub lever characteristic is set instead of the main lever characteristic when the operation lever is reversed, and the first sub lever characteristic is determined when the operation lever is reversed. In the range up to the amount, the ratio of the change in the range where the operation amount is large is smaller than the main lever characteristic set before that,
In the case where the operation speed in the dead zone is equal to or higher than a predetermined value,
When the reversal command amount is less than a predetermined value, a second sub lever characteristic is set instead of the main lever characteristic when the operation lever is reversed, and the second sub lever characteristic is determined when the operation lever is reversed. In the range up to the amount, the ratio of the change in the range where the manipulated variable is small is smaller than the main lever characteristic set before,
The set main lever characteristic is maintained when the reversal command amount is greater than or equal to a predetermined value.
It is characterized by that.

  Preferably, after the first sub-lever characteristic or the second sub-lever characteristic is set and before the operation lever is returned to the reset position in the dead zone, the set first sub-lever characteristic or the The second sub lever characteristic is maintained, and when the operation lever is returned to the reset position, the set first sub lever characteristic or the second sub lever characteristic is reset.

  Preferably, the reset position is away from the neutral position and away from the boundary between the dead zone and the operation zone.

  The present invention can provide a cargo handling device for a forklift with higher operability by including the above-described configuration.

It is a side view which shows a forklift provided with the cargo handling apparatus of one Example of this invention. It is a block diagram which shows the cargo handling apparatus of FIG. It is explanatory drawing which shows the several main lever characteristic of a cargo handling apparatus. 4A and 4B are explanatory diagrams showing control when the operation lever is reversed. 5A and 5B are explanatory diagrams showing control when the operation lever is reversed.

  Hereinafter, an example of a forklift cargo handling apparatus according to the present invention will be described. With reference to FIG. 1, the forklift includes a vehicle main body 1, a traveling wheel 2, and a cargo handling device 3 for performing a cargo handling operation. The forklift is a reach type in this embodiment, but may be a counter balance type.

  With reference to FIGS. 1 and 2, the cargo handling apparatus 3 includes a cargo handling tool 4 for supporting a workpiece. The cargo handling tool 4 is a fork in the embodiment, but may be another attachment attached instead of the fork.

  The cargo handling device 3 includes an operation lever 5 that is operated by an operator for the operation of the cargo handling tool 4. The operation lever 5 is provided in the vehicle main body 1 so as to be able to tilt forward and backward from the neutral position. In the embodiment, the operation lever 5 includes a lift lever, a tilt lever, and a reach lever.

  As shown in FIG. 2, the cargo handling device 3 includes a potentiometer 6. The potentiometer 6 is provided on the base end side of the operation lever 5 so as to output high power in proportion to the tilt angle (that is, the operation amount) from the neutral position of the operation lever 5. The potentiometer 6 functions as an operation amount detection means 7 for detecting the operation amount from the neutral position of the operation lever 5 and further functions as an operation speed detection means 8 for detecting the operation speed of the operation lever 5. The tilt angle and tilt direction (operation direction) of the operation lever 5 are obtained by the voltage output from the potentiometer 6. The operation speed of the operation lever 5 is obtained by the time change of the voltage output from the potentiometer 6.

  As shown in FIG. 2, the cargo handling device 3 includes control means 9. The control means 9 is a controller. The potentiometer 6 is connected to the control means 9.

  The cargo handling device 3 includes hydraulic drive means 10 for operating the cargo handling tool 4 by hydraulic pressure when the operation lever 5 is operated. The hydraulic drive means 10 includes a hydraulic oil storage tank, a hydraulic circuit, a hydraulic cylinder, a hydraulic motor 11, a proportional electromagnetic valve 12, and the like. In this embodiment, the hydraulic cylinder includes a lift cylinder, a tilt cylinder, and a reach cylinder.

  The hydraulic drive means 10 is driven and controlled by the control means 9. When the hydraulic motor 11 and the proportional solenoid valve 12 are driven, hydraulic oil is supplied to and discharged from the hydraulic cylinder, and the hydraulic cylinder expands and contracts. As a result, the cargo handling tool 4 operates. That is, in the embodiment, the fork performs a lift operation, a tilt operation, or a reach operation. For each operation of the fork, the cargo handling device 3 includes a mast 14, a straddle leg 15, and the like as shown in FIG.

  The operation direction of the cargo handling tool 4 is determined by the tilting direction of the operation lever 5. In this embodiment, the movement direction of the cargo handling device 4 is lift-up or lift-down, forward tilt or rear tilt, or reach-in or reach-out.

  The control means 9 determines the command amount from the tilt angle detected by the operation amount detection means 7 in accordance with the lever characteristic that defines the command amount to the hydraulic drive means 10 for the tilt angle. Then, the control means 9 drives and controls the hydraulic drive means 10 with the determined command amount. Here, the command amount is a command torque of the hydraulic motor 11 and is an exciting current of the proportional solenoid valve 12 (which determines an opening amount of the proportional solenoid valve 12). That is, when the command amount increases, the operation speed of the cargo handling tool 4 increases. As will be described later, the lever characteristics include a main lever characteristic and a sub-lever characteristic.

  FIG. 3 shows the relationship of the command amount to the hydraulic drive means 10 with respect to the tilt angle. The horizontal axis is the tilt angle of the operation lever 5, and the origin is the neutral position (θ = 0). In FIG. 3, an increase in the tilt angle from the neutral position to the right means a forward tilt of the operation lever 5, and an increase in the tilt angle from the neutral position to the left means a backward tilt of the operation lever 5. The vertical axis is the command amount.

The control means 9 is inclined even if the operation lever 5 is operated in a predetermined range (0 ≦ θ <θ ₁ ) including the neutral position in the operation range (0 ≦ θ ≦ θ _max ) of the operation lever 5. Regardless of the angle, the command amount is T = 0, and the cargo handling tool 4 is not operated. As a result, a predetermined range including the neutral position (0 ≦ θ <θ ₁ ) becomes a dead zone.

When the operation lever 5 is operated beyond the dead zone, the control means 9 controls the hydraulic drive means 10 according to the tilt angle of the operation lever 5 to operate the cargo handling equipment 4. Thereby, the range (θ ₁ ≦ θ ≦ θ _max ) up to the maximum tilt angle exceeding the dead zone becomes an operation band in which the cargo handling tool 4 is operated when the operation lever 5 is operated.

  The cargo handling device 3 includes characteristic storage means 13 (FIG. 2) in which a first main lever characteristic or an nth main lever characteristic in which a command amount with respect to a tilt angle in the operation band is determined is stored (where n is 2 or more). Natural number). The characteristic storage means 13 consists of a known storage medium. FIG. 3 shows the main lever characteristics. The main lever characteristics are stored as a table or an arithmetic expression. In this embodiment, n = 4, and the first main lever characteristic (A), the second main lever characteristic (B), the third main lever characteristic (C), and the fourth main lever characteristic (D) are characteristics. It is stored in the storage means 13.

  In this embodiment, the relationship of the command amount with respect to the tilt angle (operation amount) is the same for forward tilt and backward tilt, so only the forward tilt is described, and the description for the rear tilt is omitted. This relationship may be different between forward tilt and backward tilt, and is not limited to the examples in FIGS. 3 to 5. Further, in this embodiment, four main lever characteristics are provided, but two, three, five or more main lever characteristics may be provided.

Each main lever characteristic (A)-(D) of FIG. 3 has the following characteristics.
Each main lever characteristics (A) - In (D), the command amount T is T = 0 in the tilt angle theta = theta _1, continuously increased in proportion to the tilt angle, in the tilt angle theta = theta _max T = T _max . The command amount T is larger in the k-th main lever characteristic than the (k−1) -th main lever characteristic at an arbitrary tilt angle in the range of θ ₁ <θ <θ _max (where k is a natural number, 2 ≦ k ≦ 4). In addition, the ratio of the change in the command amount to the change in the tilt angle in the range where the tilt angle is small (that is, the slope of the tangent to the characteristic curve) is greater in the (k−1) main lever characteristic than in the kth main lever characteristic. small. On the other hand, the ratio of the change in the command amount to the change in the tilt angle in the range where the tilt angle is large is smaller in the k-th main lever characteristic than in the (k-1) main lever characteristic.

Therefore, when the command value is a range of inclination angle is less than an arbitrary value _{T A (0 <T A <} T max) and low speed range, and high-speed band range of tilt angle is equal to or greater than the predetermined value T _A, low speed zones The (k-1) main lever characteristic is larger than the kth main lever characteristic, and in the high speed band, the kth main lever characteristic is larger than the (k-1) main lever characteristic.

  That is, the (k-1) main lever characteristic is easier to adjust the speed of the cargo handling tool 4 at a lower speed than the kth main lever characteristic (that is, it is easier to finely operate the cargo handling tool 4), but at a higher speed. It is difficult to adjust the speed. On the other hand, the k-th main lever characteristic is more difficult to adjust the speed of the cargo handling device 4 at a low speed than the (k-1) main lever characteristic, but is easy to adjust the speed at a high speed.

Next, setting of the main lever characteristic will be described.
When the operation lever 5 is operated from the neutral position to the operation band by the operator to the operation band, the control means 9 operates the operation lever 5 in the dead band at that time by the operation amount detection means 7 and the operation speed detection means 8. Obtain the velocity _Vf . The operation speed V _f may be an average speed when the operating lever 5 passes through the dead zone, or may be a maximum speed detected when moving the dead zone, or passes through a predetermined position in the dead zone. It may be the speed of time.

The control means 9 sets any one of the first main lever characteristics (A) to the fourth main lever characteristics (D) based on the operation speed V _f in the dead zone. The control means 9 sets the main lever characteristic having a smaller rate of change in the range where the tilt angle is larger, that is, the main lever characteristic having a larger high speed zone, as the operation speed _Vf is larger. More specifically, the control means 9 provides the first main lever characteristic (A) when 0 <V _f <V ₁ , and the second main lever characteristic (B) when V ₁ ≦ V _f <V ₂ . The third main lever characteristic (C) is set when V ₂ ≦ V _f <V ₃ , and the fourth main lever characteristic (D) is set when V ₃ ≦ V _f .

  The control means 9 operates the cargo handling implement 4 by controlling the hydraulic drive means 10 according to the main lever characteristics set as described above.

  Generally, the operator slowly tilts the operation lever 5 from the neutral position when it is desired to operate the cargo handling device 4 at a low speed. In such a case, the first main lever characteristic (A) and the second main lever characteristic (B) are used. Thus, the main lever characteristic that allows the speed adjustment at a low speed of the cargo handling tool 4 to be relatively easy is automatically set. Further, when the operator wants to operate the cargo handling tool 4 at a high speed, the operator levers the operating lever 5 from the neutral position. In such a case, the third main lever characteristic (C) and the fourth main lever characteristic (D) Such a main lever characteristic that makes it relatively easy to adjust the speed of the cargo handling device 4 at high speed is automatically set.

Next, control when the operation lever 5 is reversed toward the neutral position (the cargo handling tool 4 is decelerated) after the main lever characteristics are set as described above will be described. The control at this time differs depending on whether the main lever characteristic that allows easy speed adjustment at a low speed is set or the main lever characteristic that allows easy speed adjustment at a high speed. That is, different control is performed when the operation speed _Vf in the dead zone is less than a predetermined value and when the operation speed _Vf is a predetermined value or more. The control means 9 detects the reversal of the operation lever 5 based on the outputs from the potentiometer 6 (the operation amount detection means 7 and the operation speed detection means 8).

In this embodiment, the first main lever characteristic (A) and the second main lever characteristic (B) that are easy to adjust the speed at a low speed are set, and the third main lever characteristic that is easy to adjust the speed at a high speed. (C) Control differs depending on whether the fourth main lever characteristic (D) is set. That is, different control is performed when the operation speed V _f is V _f <V ₂ and when V _f ≧ V ₂ .

First, an example in which the first main lever characteristic (A) is set will be described as a case where V _f <V ₂ . As shown in FIG. 4, when the control means 9 detects that the operation lever 5 has been reversed toward the neutral position after setting the first main lever characteristic (A), the command amount at the time of the reversal (hereinafter referred to as reversal). It is determined whether the hour command amount T _r ) is less than a predetermined value or more than a predetermined value.

As Figure 4A, if the inversion time of the reference variable _{T r} is less than the predetermined threshold value _{T h (T r <T h} ), the control unit 9 maintains the first main lever characteristics set (A), according to which The cargo handling device 4 is operated by controlling the hydraulic drive means 10.

On the other hand, as in FIG. 4B, when inverted when the reference variable _{T r} is equal to or larger than the threshold _{T h (T r ≧ T h} ), the control unit 9, the first sub in place of the first main lever characteristics set (A) Set the lever characteristics (X). That is, the control means 9 switches the lever characteristic from the first main lever characteristic (A) to the first sub lever characteristic (X) when the operation lever 5 is reversed.

This first sub-lever characteristic (X) has the following characteristics in the range up to the tilt angle at the time of reversal of the operation lever 5 (hereinafter, tilt angle at the time of reversal θ _r ), that is, θ ₁ ≦ θ ≦ θ _r . Have As Figure 4B, the reference variable T of the first sub-lever characteristics (X) is T = 0 in the tilt angle theta = theta _1, continuously increased in proportion to the tilt angle, the tilt angle theta = theta _r The command amount T becomes equal to _Tr . The command amount T is larger at the first sub-lever characteristic (X) than the first main lever characteristic (A) set before that at an arbitrary tilt angle of θ ₁ <θ <θ _r . The ratio of the change in the command amount to the change in the operation angle when the operation angle is small is greater in the first sub lever characteristic (X) than in the first main lever characteristic (A) set before that. The ratio of the change in the range where the angle is large is smaller in the first sub lever characteristic (X) than in the first main lever characteristic (A) set before that. That is, in θ ₁ ≦ θ ≦ θ _r , speed adjustment at high speed is easier for the first sub-lever characteristic (X) than for the first main lever characteristic (A).

The first sub-lever characteristic (X) in such θ ₁ ≦ θ ≦ θ _r is, for example, other than the first main lever characteristic (A) set before that, the speed adjustment at higher speed is easier. It is calculated by the control means 9 using any of the main lever characteristics (B)-(D). In this embodiment, the control means 9 is such that the characteristic curve of the first auxiliary lever characteristic (X) passes through the point (θ ₁ , 0) and the point (θ _r , T _r ), and the third main lever characteristic in FIG. The characteristic curve of (C) (θ ₁ ≦ θ ≦ θ _max , 0 ≦ T ≦ T _max ) is reduced to the region of θ ₁ ≦ θ ≦ θ _r , 0 ≦ T ≦ T _r , One sub lever characteristic (X) is calculated. That is, the control means 9 calculates and sets the first sub lever characteristic (X) as described above using the third main lever characteristic (C) and a predetermined calculation formula when the operation lever 5 is reversed. To do. The calculation of the first sub-lever characteristic (X) is not limited to this, and other methods may naturally be adopted.

The command amount T of the first auxiliary lever characteristic (X) when θ _r <θ ≦ θ _max may be, for example, the same as the first main lever characteristic (A) set before that, or T = T _r It may be constant.

  Then, the control means 9 operates the cargo handling tool 4 by controlling the hydraulic drive means 10 according to the first sub-lever characteristic (X).

In the case of V _f <V ₂ , when the second main lever characteristic (B) is set, the same control as when the first main lever characteristic (A) is set is performed.

As described above, when the main lever characteristic that allows easy speed adjustment at a low speed is set, if the inversion command amount _Tr is less than a predetermined value (FIG. 4A), the main lever characteristic being set is maintained. The That is, when the operator is operating the cargo handling tool 4 at a low speed by the operation lever 5, even if the operation lever 5 is reversed, the state where the speed adjustment (fine operation) at a low speed is easy to continue.

On the other hand, when the main lever characteristic is set so that speed adjustment at low speed is easy (speed adjustment at high speed is difficult), if the reversal command amount _Tr is greater than or equal to a predetermined value (FIG. 4B), The first sub-lever characteristic (X) is switched. As described above, the first sub-lever characteristic (X) is easier than the main lever characteristic in which the high-speed speed adjustment is set before θ ₁ ≦ θ ≦ θ _r . For example, when the operator slowly tilts the operation lever 5 to slowly accelerate the cargo handling device 4 to operate at high speed, and then returns the operation lever 5 to decelerate the cargo handling device 4, it is difficult to adjust the speed at high speed. If the main lever characteristic is maintained, it is difficult to operate the cargo handling device 4. In the cargo handling device 3, the first auxiliary lever characteristic (X) that allows easy speed adjustment at a high speed is switched, so that the cargo handling tool 4 can be easily operated (decelerated) even in such a case.

Next, an example when the fourth main lever characteristic (D) is set will be described as a case where V _f ≧ V ₂ . As shown in FIG. 5, when the control means 9 detects that the operation lever 5 has been reversed toward the neutral position after setting the fourth main lever characteristic (D), the reverse command amount T _It is determined whether _r is less than a predetermined value or more than a predetermined value.

As Figure 5A, if the inversion time of the reference variable _{T r} is less than the threshold value _{T h (T r <T h} ), the control unit 9, the second sub-lever characteristics instead of the fourth main lever characteristics set (D) (Y) is set. That is, the control means 9 switches the lever characteristic from the fourth main lever characteristic (D) to the second sub lever characteristic (Y) when the operation lever 5 is reversed.

The second sub-lever characteristic (Y) has the following characteristics in the range up to the operating angle θ _r during reversal, that is, in θ ₁ ≦ θ ≦ θ _r . As Figure 5A, the reference variable T of the second auxiliary lever characteristics (Y) is T = 0 in the tilt angle theta = theta _1, continuously increased in proportion to the tilt angle, the tilt angle theta = theta _r The command amount T becomes equal to _Tr . The command amount T is smaller than the fourth main lever characteristic (D) set before the second sub lever characteristic (Y) at an arbitrary tilt angle of θ ₁ <θ <θ _r . The ratio of the change in the command amount to the change in the operation angle in the range where the operation angle is small is smaller in the second sub lever characteristic (Y) than the fourth main lever characteristic (D) set before that. The ratio of the change in the range where the angle is large is larger in the second sub-lever characteristic (Y) than in the fourth main lever characteristic (D) set before that. That is, in the case of θ ₁ ≦ θ ≦ θ _r , speed adjustment at a low speed is easier for the second sub lever characteristic (Y) than for the fourth main lever characteristic (D).

The second sub-lever characteristic (Y) in such θ ₁ ≦ θ ≦ θ _r is, for example, other than the fourth main lever characteristic (D) that has been set before that, the speed adjustment at a low speed is easier. It is calculated by the control means 9 using any of the main lever characteristics (A)-(C). In this embodiment, the control means 9 is such that the characteristic curve of the second auxiliary lever characteristic (Y) passes through the point (θ ₁ , 0) and the point (θ _r , T _r ), and the first main lever characteristic in FIG. The characteristic curve of (A) (θ ₁ ≦ θ ≦ θ _max , 0 ≦ T ≦ T _max ) is reduced to the region of θ ₁ ≦ θ ≦ θ _r , 0 ≦ T ≦ T _r , The two-sub lever characteristic (Y) is calculated. That is, the control means 9 calculates and sets the second auxiliary lever characteristic (Y) as described above using the first main lever characteristic (A) and a predetermined calculation formula when the operation lever 5 is reversed. To do. The calculation of the second sub lever characteristic (Y) is not limited to this, and other methods may be adopted.

The command amount T of the second auxiliary lever characteristic (Y) at θ _r <θ ≦ θ _max may be the same as the fourth main lever characteristic (D) set before, for example, or T = Tr It may be constant.

  And the control means 9 drives the hydraulic drive means 10 according to the 2nd sub lever characteristic (Y), and operates the cargo handling implement 4. FIG.

On the other hand, as in FIG 5B, if during inversion reference variable _{T r} is not smaller than a predetermined threshold value _{T h (T r ≧ T h} ), the control unit 9 maintains fourth main lever characteristics set the (D), In accordance with this, the hydraulic drive means 10 is driven and controlled.

As in the case of V _f ≧ V ₂ , when the third main lever characteristic (C) is set, the same control as that when the fourth main lever characteristic (D) is set is performed.

As described above, when the main lever characteristic is set such that speed adjustment at high speed is easy (speed adjustment at low speed is difficult), and the inversion command amount _Tr is less than a predetermined value (FIG. 5A). The second sub lever characteristic (Y) is switched to. The second sub-lever characteristic (Y) is easier to adjust at low speed than the main lever characteristic previously set when θ ₁ ≦ θ ≦ θ _r as described above. For example, if the operator depresses the operating lever 5 vigorously but actually wants to operate the cargo handling device 4 at a low speed and returns the operating lever 5, the main lever characteristic that makes it difficult to adjust the speed at a low speed remains set. Then, it is difficult to perform fine operations. In this loading / unloading device 3, the second auxiliary lever characteristic (Y) that allows easy speed adjustment at low speed is switched, so that it becomes easy to finely operate the loading / unloading tool 4 even in such a case.

On the other hand, when the main lever characteristic that allows easy speed adjustment at high speed is set, if the inversion command amount _Tr is greater than or equal to a predetermined value (FIG. 5B), the main lever characteristic being set is maintained. That is, when the operator is operating the cargo handling tool 4 at high speed with the operation lever 5, even if the operation lever 5 is reversed, the state where the speed adjustment at high speed is easy continues.

As described above, according to the cargo handling device 3 of the present invention, the main lever characteristics (A) to (D) depend on whether the reversal command amount _Tr when the operation lever 5 is reversed to the neutral position is less than a predetermined value or more than a predetermined value. It is determined whether to maintain or switch to the first sub-lever characteristic (X) or the second sub-lever characteristic (Y) described above. Thereby, the cargo handling apparatus 3 of this invention can always provide an operator with the optimal operativity when returning the operation lever 5 to a neutral position, and the operativity is higher.

  Then, when the control means 9 detects that the operating lever 5 has been returned to the reset position within the dead zone, the control lever 9 resets the currently set lever characteristic (main lever characteristic or sub lever characteristic). In addition, after the sub-lever characteristic is set, it is not so much to reverse the operation lever 5 again to greatly increase the command amount (to greatly increase the speed of the cargo handling tool 4). Therefore, even if the control lever 9 is tilted in the direction away from the neutral position again after the first sub-lever characteristic (X) or the second sub-lever characteristic (Y) is set, the control means 9 The set first sub-lever characteristic (X) or second sub-lever characteristic (Y) is maintained until the reset position is returned. When the control means 9 detects that the operation lever 5 has been returned to the reset position, it resets the set first sub-lever characteristic (X) or second sub-lever characteristic (Y).

Note that the reset position is set within the dead zone, but is preferably a position away from the neutral position and away from the boundary (θ = θ ₁ ) between the dead zone and the operation zone.

  The operator may operate the operation lever 5 to the operation zone again without completely returning to the neutral position. By setting the reset position to a position away from the neutral position, the lever characteristic suitable for the next operation is automatically set even in such a case. Of course, the reset position may be set to the neutral position. In order to adjust the position of the cargo handling tool 4, the operator may finely operate the operation lever 5 within a small tilt angle within the operation band. At this time, the operation lever 5 is slightly moved from the operation band to the dead band. May end up. By setting the neutral position to a position somewhat away from the boundary between the dead zone and the operation zone, the lever characteristics are maintained without being reset even in such a case, and the operator can continue to finely operate the cargo handling device 4. it can.

As mentioned above, although the preferable Example of this invention was described, this invention is not limited to the said Example. In order to determine a first threshold value T _h to determine whether to switch the sub-lever characteristics (X) described in Figure 4, or switched to the second sub-lever characteristics described in FIG. 5 (Y) the threshold T _h may be a well different values for the same value. Further, the threshold _{T h} is mainly lever characteristics (A) - (D) may be determined for each.

DESCRIPTION OF SYMBOLS 1 Vehicle main body 2 Wheel 3 Handling apparatus 4 Handling tool 5 Operation lever 6 Potentiometer 7 Operation amount detection means 8 Operation speed detection means 9 Control means 10 Hydraulic drive means 11 Hydraulic motor 12 Proportional solenoid valve 13 Characteristic storage means 14 Mast 15 Straddle leg ( A) First main lever characteristic (B) Second main lever characteristic (C) Third main lever characteristic (D) Fourth main lever characteristic (X) First sub lever characteristic (Y) Second sub lever characteristic

Claims (3)

A load handling device, an operation lever for operating the load handling device, a hydraulic drive means for operating the load handling device by hydraulic pressure when the operation lever is operated, and an operation amount from a neutral position of the operation lever. An operation amount detection means for detecting, and an operation speed detection means for detecting an operation speed of the operation lever,
Of the operating range of the operating lever, a predetermined range including the neutral position is a dead zone in which the cargo handling equipment is not operated even when the operating lever is operated, and the operating lever is operated in a range exceeding the dead zone. And an operation band in which the cargo handling equipment is operated,
Characteristic storage means for storing a first main lever characteristic to an nth main lever characteristic in which a command amount to the hydraulic drive means with respect to the operation amount in the operation band is determined (n is a natural number of 2 or more);
Each of the first main lever characteristic to the n-th main lever characteristic has a characteristic that the command amount increases in proportion to the operation amount, and the change with respect to a change in the operation amount in a range where the operation amount is small. The change rate of the command amount is such that the (k-1) main lever characteristic is smaller than the kth main lever property, and the change rate in the range where the operation amount is large is the kth main lever property It is smaller than the (k-1) th main lever characteristic (k is a natural number satisfying 2 ≦ k ≦ n),
The main lever has a smaller rate of change in a larger range of operation as the operation speed in the dead zone is larger when the operation lever is operated from the neutral position to the operation zone beyond the dead zone. A forklift cargo handling device having characteristics set,
In the case where the operation speed in the dead zone is less than a predetermined value,
When the command amount at the time of reversal as the command amount at the time of reversing toward the neutral position of the operation lever is less than a predetermined value, the set main lever characteristic is maintained,
When the reversal command amount is greater than or equal to a predetermined value, a first sub lever characteristic is set instead of the main lever characteristic when the operation lever is reversed, and the first sub lever characteristic is determined when the operation lever is reversed. In the range up to the amount, the ratio of the change in the range where the manipulated variable is large is smaller than the main lever characteristic set before that,
In the case where the operation speed in the dead zone is equal to or higher than a predetermined value,
When the reversal command amount is less than a predetermined value, a second sub lever characteristic is set instead of the main lever characteristic when the operation lever is reversed, and the second sub lever characteristic is determined when the operation lever is reversed. In the range up to the amount, the ratio of the change in the range where the manipulated variable is small is smaller than the main lever characteristic set before that,
The set main lever characteristic is maintained when the reversal command amount is greater than or equal to a predetermined value.
A forklift cargo handling device characterized in that.   After the first sub-lever characteristic or the second sub-lever characteristic is set, the set first sub-lever characteristic or the second sub-lever characteristic is set until the operation lever is returned to the reset position in the dead zone. The lever characteristic is maintained, and when the operation lever is returned to the reset position, the set first sub-lever characteristic or the second sub-lever characteristic is reset. Forklift handling equipment.   The forklift loading / unloading apparatus according to claim 2, wherein the reset position is located away from the neutral position and away from a boundary between the dead zone and the operation zone.

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