Heaviness changing system

Abstract

To change heaviness of a pedal operation and a lever operation of a forklift truck or either of them in accordance with an operator's stress level such as to decrease concentration.SOLUTION: A heaviness changing system S comprises a heaviness changing part 21, and a change command part 306. The heaviness changing part 21 changes heaviness of a pedal 14 and a lever 15 of a forklift truck or either of them. The change command part 306 changes the heaviness of the pedal and the lever or either of them by controlling the heaviness changing part 21 in accordance with an operator's stress level.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a weight change system for changing the weight of a pedal and a lever of a forklift or the weight of any one of them.

Background Art

[0002] Forklifts include types such as reach forklifts and counterbalanced forklifts. Forklifts are equipped with pedals and levers, and the number and functions thereof differ depending on the type of forklift.

[0003] As disclosed in Patent Document 1, a reach forklift is equipped with a brake pedal and a presence pedal. The presence pedal is configured to be able to stop traveling and cargo handling, and the driver cannot travel or perform cargo handling unless the presence pedal is depressed. Also, as disclosed in Patent Document 2, a counterbalanced forklift is equipped with an accelerator pedal and a brake pedal, and an engine-type counterbalanced forklift further includes a clutch pedal. Among battery-powered forklifts, an automatic forklift further includes an inching pedal instead of a clutch pedal. By depressing the inching pedal, the driver can put the forklift in a semi-clutch state and cut off the driving power.

[0004] In addition, as disclosed in Patent Document 3, a reach-type forklift includes a lift lever for raising and lowering the forks, a tilt lever for changing the vertical angle of the forks, a reach lever for moving the lifting device forward and backward, and an accelerator lever for driving the forklift. Further, as disclosed in Patent Document 4, a counterbalanced forklift includes a tilt lever and an accelerator lever. Generally, as disclosed in Patent Document 5, a lever is configured to swing forward or backward from a neutral position and automatically return to the neutral position by a spring when not in operation. The invention disclosed in Patent Document 5 assists lever operation by an actuator when the operation amount of the operation lever exceeds a predetermined value in order to reduce the fatigue of the operator. In addition, for example, Patent Document 6 discloses a technique for assisting the lever operation of a vehicle.

[0005] By the way, when it is desired to quickly perform pedal operation or lever operation, it is preferable that they are lighter in weight. However, the lighter the weight, the easier it is to lead to a large operation error unless the operation is performed more carefully. It would be ideal if careful operation could always be performed, but human concentration has fluctuations and it is not possible to always exert maximum concentration. Also, it is known that human concentration decreases when stressed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, the problem to be solved by the present invention is to provide a weight change system that can change the pedal operation and lever operation of a forklift or the weight of either of them according to the stress level of the driver that causes a decrease in concentration.

Means for Solving the Problems

[0008] To solve the above problems, the weight change system according to the present invention used in a forklift includes a weight change unit that changes the weight of the pedal and lever of the forklift or either of them, and a change command unit that controls the weight change unit according to the stress level of the driver to change the weight of the pedal and lever or either of them.

[0009] The above weight change system preferably further includes stress level estimation means for estimating the stress level of the driver.

[0010] The above weight change system preferably further includes temperature and humidity measurement means for measuring temperature and humidity, a discomfort index calculation unit for calculating a discomfort index from the temperature and humidity, and a stress level estimation unit for estimating the stress level of the driver based on the calculated discomfort index, and the change command unit changes the weight of the pedal and lever or either of them according to the estimated stress level of the driver.

[0011] The above weight change system preferably further includes sound collection means for collecting ambient sound, and a stress level estimation unit for estimating the stress level of the driver based on the volume of the ambient sound, and The change instruction unit changes the weight of the pedal and lever or either of them according to the presumed stress level of the driver.

[0012] The above weight change system preferably further includes a storage unit that stores the driver's work schedule including the amount of work per hour, a stress level estimation unit that refers to the work schedule and estimates the stress level of the driver according to the amount of work per hour. The change instruction unit changes the weight of the pedal and lever or either of them according to the presumed stress level of the driver.

[0013] The above weight change system preferably further includes a storage unit that stores the driver's work schedule including the amount of work within the same area, a stress level estimation unit that refers to the work schedule and estimates the stress level of the driver according to the amount of work within the same area. The change instruction unit changes the weight of the pedal and lever or either of them according to the presumed stress level of the driver.

[0014] The above weight change system preferably further includes a storage unit that stores the driver's work schedule including the size of the work area, a stress level estimation unit that refers to the work schedule and estimates the stress level of the driver according to the size of the work area. The change instruction unit changes the weight of the pedal and lever or either of them according to the presumed stress level of the driver.

[0015] The above weight change system preferably further includes a storage unit that stores the driver's work schedule including the number of people within the work area, a stress level estimation unit that refers to the work schedule and estimates the stress level of the driver according to the number of people within the work area. The change instruction unit changes the weight of the pedal and lever or either of them according to the presumed stress level of the driver.

[0016] The above weight change system preferably further includes a stress level estimation unit that estimates the stress level of the driver based on at least one piece of information among the amount of work per hour, the working time in the same area, the size of the working area, and the number of people in the working area. The change instruction unit changes the weight of the pedal and lever or either of them according to the presumed stress level of the driver.

[0017] To solve the above problems, the forklift according to the present invention includes the weight change system described in any of the above.

[0018] To solve the above problems, the weight change program according to the present invention is a program used in a weight change system including a weight change unit that changes the weight of the pedal and lever of the forklift or either of them and a computer, and causes the computer to control the weight change unit to change the weight of the pedal and lever or either of them according to the stress level of the driver.

Effect of the Invention

[0019] The weight change system according to the present invention can change the pedal operation and lever operation of the forklift or the weight of either of them according to the stress level of the driver that causes a decrease in concentration.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0021] <First Embodiment> Hereinafter, with reference to FIGS. 1 to 3, a first embodiment of a weight change system according to the present invention will be described. The weight change system S according to the present embodiment is configured to change the weights of both the pedal and the lever, but this is merely an example, and the weight change system according to the present invention may be configured to change the weight of either the pedal or the lever.

[0022] <Configuration of Forklift> FIG. 1 is a front view of a forklift 1 provided with a weight change system S. First, the configuration of the forklift 1 will be described. The forklift 1 is a battery-powered counterbalanced forklift. As shown in FIG. 1, the forklift 1 includes a plurality of wheels 10, a vehicle body 11, a driver's seat 12, a head guard 13, a pedal 14 (see FIG. 2), a lever 15, left and right masts 16, left and right forks 17, a speaker 19 (see FIG. 2), a microphone 20 (see FIG. 2), a weight change unit 21 (see FIG. 2), a stress degree estimation means 22 (see FIG. 2), and a control unit 30 (see FIG. 2).

[0023] A plurality of wheels 10 are provided on the four sides of the vehicle body 11. The driver's seat 12 is provided on the vehicle body 11, and the head guard 13 is provided above the driver's seat 12.

[0024] The pedal 14 has an accelerator pedal, a brake pedal, and a tilting pedal, and is provided below the driver's seat 12. The "pedal" in the present invention only needs to have at least one pedal such as an accelerator pedal, a brake pedal, and a tilting pedal, and does not necessarily have all of these pedals.

[0025] The lever 15 has a lift lever and a tilt lever, and is provided at the front of the driver's seat 12. The lever 15 may have a slide lever for sliding the fork 17 left and right. The "lever" in the present invention only needs to have at least one lever such as a lift lever and a tilt lever, and does not necessarily have all of these levers.

[0026] The left and right forks 17 are configured to be able to move up and down via the left and right masts 16, and the driver H operates the lift lever to move the fork 17 up and down to perform a loading and unloading operation.

[0027] The microphone 20 collects the speech voice of the driver H, converts the collected voice into a voice signal, and transmits it to the control unit 30.

[0028] The speaker 19 emits a warning voice for notifying the driver H of a warning of a weight change to be described later. The warning voice may be, for example, "The weights of the pedal and the lever will be increased. Is that okay?" when the weights of the pedal 14 and the lever 15 are increased, or "The weights of the pedal and the lever will be decreased. Is that okay?" when the weights of the pedal 14 and the lever 15 are decreased.

[0029] The weight change unit 21 changes the weights of the lever 15 and the pedal 14 during operation based on the command of a change command unit 306 (see FIG. 2) to be described later. The weight change unit 21 includes a pedal weight change unit that changes the weight of the pedal 14 and a lever weight change unit that operates the weight of the lever 15. Note that when the weight change unit 21 is configured to change the weight of either one of the pedal 14 and the lever 15, it will have either one of the pedal weight change unit and the lever weight change unit.

[0030] The pedal weight change unit changes the weight of the pedal 14 when the driver H steps on it based on the command of the change command unit 306. The pedal weight change unit is configured by, for example, a device that can adjust the weight by hydraulic pressure or a device that can adjust the weight by a spring.

[0031] Also, for example, the pedal weight change unit may be an assist device that assists the stepping force of the pedal 14. In this case, the pedal weight change unit may adjust the assist force based on the command of the change command unit 306 and substantially change the weight of the pedal 14 when the driver H steps on it.

[0032] Or, for example, the pedal weight change unit may be configured to change the magnitude of the driving force or the braking force of each device that responds to the stepping amount of the pedal 14 based on the command of the change command unit 306. Thereby, the pedal weight change unit substantially changes the weight of the pedal 14.

[0033] The lever weight change unit is configured by, for example, a device that can adjust the weight of the lever 15 by hydraulic pressure or a device that can adjust the weight of the lever 15 by a spring.

[0034] Also, for example, the lever weight change unit may be an assist device that assists the operation of the weight of the lever 15. In this case, the lever weight change unit may adjust the assist force based on the command of the change command unit 306 and substantially change the weight of the lever 15 when the driver H operates it.

[0035] Alternatively, the lever weight changing unit may be configured to change the magnitude of the power of each device that responds to the operation amount of the lever 15, for example, based on a command from the change command unit 306. Thereby, the lever weight changing unit substantially changes the weight of the lever 15.

[0036] The stress level estimating means 22 estimates the stress level of the driver H. The stress level estimating means 22 may be known means such as those that measure using electrocardiogram and pulse wave or those that measure using heartbeat variation, for example, as disclosed on the following web pages, and is not particularly limited. ·https: / / www.hitachi-systems.com / ind / fses / ·https: / / medical.murata.com / ja-jp / products / fatigue

[0037] The control unit 30 is constituted by a computer disposed in the vehicle body 11 and includes an arithmetic unit, a storage device, and a memory. The storage device stores a weight change program to be executed as a stress level reading unit 302, a weight determination unit 303, a change notice unit 304, a response receiving unit 305, and a change command unit 306, which will be described later for the computer.

[0038] <Functional Configuration of the First Embodiment> Next, the functional configuration of the weight change system S will be described. As shown in FIG. 2, the control unit 30 includes a storage unit 301, a stress level reading unit 302, a weight determination unit 303, a change notice unit 304, a response receiving unit 305, and a change command unit 306.

[0039] The storage unit 301 stores the correspondence relationship between the stress level and the weights of the pedal 14 and the lever 15 corresponding thereto.

[0040] The stress level reading unit 302 reads the stress level of the driver H estimated by the stress level estimating means 22.

[0041] The weight determination unit 303 determines the weights of the pedal 14 and the lever 15 based on the stress level of the driver H read and the weights of the pedal 14 and the lever 15 corresponding to the stress level stored in the storage unit 301.

[0042] If the weights of the pedal 14 and the lever 15 determined by the weight determination unit 303 are different from the weights of the pedal 14 and the lever 15 at that time, the change notification unit 304 determines that it is necessary to change the weights of the pedal 14 and the lever 15. Then, when the change notification unit 304 determines that it is necessary to change the weights of the pedal 14 and the lever 15, it notifies the driver H of the change in the weights of the pedal 14 and the lever 15 by voice from the speaker 19. However, it is not preferable for the weights of the pedal 14 and the lever 15 to be changed frequently. Therefore, the change notification unit 304 is configured to leave an arbitrary interval until the next notification after giving the notification. This interval may be set, for example, between 5 minutes and 30 minutes.

[0043] The response reception unit 305 receives a predetermined response from the driver H notified by the change notification unit 304 via the microphone 20. For example, the predetermined response may be words such as "yes", "I understand", "acknowledged". When the response reception unit 305 receives a predetermined response from the driver H, it transmits a response signal to the change command unit 306.

[0044] When receiving the response signal, the change command unit 306 controls the weight change unit 21 to change the weights of the pedal 14 and the lever 15 to the weights determined by the weight determination unit 303. Thereby, even if the concentration of the driver H fluctuates due to stress, the weight change system S can change the weights of the pedal 14 and the lever 15 according to the stress level.

[0045] As a result, when the driver H is highly concentrated, the weight change system S can make the operations of the pedal 14 and the lever 15 quick by reducing the weights of the pedal 14 and the lever 15. Also, when the driver H has low concentration, the weight change system S can prevent major operation mistakes by increasing the weights of the pedal 14 and the lever 15.

[0046] <Flow of the weight change system according to the first embodiment> Next, with reference to the flowchart of FIG. 3, the operation of the weight change system S according to the first embodiment will be described again.

[0047] (1) First, the weight change system S reads the stress level of the driver H (see S31 in FIG. 3).

[0048] (2) Next, the weight change system S determines the weights of the pedal 14 and the lever 15 with reference to the stress level of the driver H (see S32 in FIG. 3).

[0049] (3) Next, if the determined weights of the pedal 14 and the lever 15 are different from the weights of the pedal 14 and the lever 15 at that time, the weight change system S determines that a change is necessary (Yes in S33 in FIG. 3), and notifies the driver H of the change in the weights of the pedal 14 and the lever 15 (see S34 in FIG. 3).

[0050] (4) Next, when the weight change system S receives permission for the change from the driver H (Yes in S35 in FIG. 3), the weight change system S changes the weights of the pedal 14 and the lever 15 by the change command unit 306 (see S36 in FIG. 3). Also, until the weight change system S receives permission for the change from the driver H (No in S35 in FIG. 3), the weight change system S holds the change in the weights of the pedal 14 and the lever 15, and notifies the driver H of the change in the weight of the lever 15 again after a predetermined time. Thereby, the weight change system S can prevent frequently changing the weights of the pedal 14 and the lever 15 and suddenly changing the weights of the pedal 14 and the lever 15 during the loading work of the driver H.

[0051] In this way, the weight change system S changes the weights of the pedal 14 and the lever 15 based on the stress level that affects the driver H's concentration. As a result, when the driver H has high concentration, the operations of the pedal 14 and the lever 15 can be performed quickly, and when the driver H has low concentration, major operation mistakes can be prevented.

[0052] <Second Embodiment> Next, with reference to FIGS. 1, 4, and 5, a second embodiment of the weight change system according to the present invention will be described. The weight change system S according to this embodiment is also configured to change the weights of both the pedal and the lever, similar to the first embodiment. Hereinafter, for the same configurations as those in the first embodiment, the same reference numerals may be given and the detailed description thereof may be omitted.

[0053] The forklift 1 according to this embodiment is a counterbalanced forklift similar to that in the first embodiment. As shown in FIGS. 1 and 4, it includes a plurality of wheels 10, a vehicle body 11, a driver's seat 12, a head guard 13, a pedal 14, a lever 15, left and right masts 16, left and right forks 17, a speaker 19, a microphone 20, a weight change unit 21, a thermometer 23, a hygrometer 24, and a control unit 30.

[0054] The thermometer 23 measures the temperature around the driver's seat 12, and the hygrometer 24 measures the humidity around the driver's seat 12. As in this embodiment, the "temperature and humidity measuring means" of the present invention may be configured separately as the thermometer 23 and the hygrometer 24.

[0055] The weight change unit 21 changes the weights of the lever 15 and the pedal 14 during operation based on the command of the change command unit 306 (see FIG. 4) in the same manner as in the first embodiment. The weight change unit 21 has a pedal weight change unit that changes the weight of the pedal 14 and a lever weight change unit that operates the weight of the lever 15, similar to the first embodiment.

[0056] <Functional Configuration of the Second Embodiment> Next, the functional configuration of the weight change system S according to the second embodiment will be described. As shown in FIG. 4, the control unit 30 includes a storage unit 301, a temperature and humidity reading unit 307, a discomfort index calculation unit 308, a stress level estimation unit 309, a weight determination unit 303, a change notice unit 304, a response receiving unit 305, and a change command unit 306.

[0057] Similar to the first embodiment, the storage unit 301 stores the correspondence between the stress level and the weights of the pedal 14 and the lever 15 corresponding thereto.

[0058] The temperature and humidity reading unit 307 reads the temperature and humidity around the driver's seat 12 measured by the thermometer 23 and the hygrometer 24.

[0059] The discomfort index calculation unit 308 refers to the read temperature and humidity around the driver's seat 12 and calculates the discomfort index according to the following formula. It is known that a person's concentration decreases depending on the degree of the discomfort index. Formula... 0.81 × temperature + 0.01 × humidity (%) × (0.99 × temperature - 14.3) + 46.3

[0060] The stress level estimation unit 309 estimates the stress level based on the calculated discomfort index. The stress level estimation unit 309 estimates that the higher the discomfort index, the higher the stress level, and the lower the discomfort index, the lower the stress level.

[0061] The weight determination unit 303 determines the weights of the pedal 14 and the lever 15 based on the estimated stress level and the weights of the pedal 14 and the lever 15 corresponding to the stress level stored in the storage unit 301.

[0062] Similar to the first embodiment, when it is determined that the weights of the pedal 14 and the lever 15 need to be changed, the change notice unit 304 notifies the driver H of the change in the weights of the pedal 14 and the lever 15 by voice using the speaker 19.

[0063] The response receiving unit 305, similar to the first embodiment, receives a predetermined response of the driver H announced by the change notice unit 304 via the microphone 20 and transmits a response signal to the change command unit 306.

[0064] Upon receiving the response signal, the change command unit 306, similar to the first embodiment, controls the weight change unit 21 to change the weights of the pedal 14 and the lever 15 to the weights determined by the weight determination unit 303. As a result, the weight change system S can change the weights of the pedal 14 and the lever 15 according to the stress level related to the discomfort index even if the concentration of the driver H fluctuates due to the stress related to the discomfort index.

[0065] <Flow of the weight change system according to the second embodiment> Next, with reference to the flowchart of FIG. 5, the operation of the weight change system S according to the second embodiment will be described again.

[0066] (1) First, the weight change system S reads the temperature and humidity around the driver's seat 12 (see S51 in FIG. 5) and calculates the discomfort index based on the read temperature and humidity (see S52 in FIG. 5).

[0067] (2) Next, the weight change system S estimates the stress level of the driver H based on the calculated discomfort index (see S53 in FIG. 5).

[0068] (3) Next, the weight change system S determines the weights of the pedal 14 and the lever 15 with reference to the estimated stress level of the driver H (see S54 in FIG. 5).

[0069] (4) Next, the weight change system S determines that a change is necessary if the determined weights of the pedal 14 and the lever 15 are different from the weights of the pedal 14 and the lever 15 at that time (Yes in S55 in FIG. 5), and announces to the driver H the change in the weights of the pedal 14 and the lever 15 (see S56 in FIG. 5).

[0070] (5) Next, when the weight change system S receives permission for the change from the driver H (Yes in S57 of FIG. 5), the change command unit 306 changes the weights of the pedal 14 and the lever 15 (see S58 of FIG. 5). Also, until the weight change system S receives permission for the change from the driver H (No in S57 of FIG. 5), the weight change of the pedal 14 and the lever 15 is suspended, and the driver H is notified again of the weight change of the lever 15 after a predetermined time.

[0071] As described above, the weight change system S according to the present embodiment changes the weights of the pedal 14 and the lever 15 based on the stress level related to the discomfort index that affects the level of the driver H's concentration. As a result, when the driver H has a high concentration, the operations of the pedal 14 and the lever 15 can be performed quickly, and when the driver H has a low concentration, major operation mistakes can be prevented.

[0072] <Third Embodiment> Next, a third embodiment of the weight change system according to the present invention will be described with reference to FIGS. 1, 6, and 7. The weight change system S according to the present embodiment is also configured to change the weights of both the pedal and the lever, similar to the above embodiment. Hereinafter, for the same configurations as those in the above embodiment, the same reference numerals may be given and the detailed description thereof may be omitted.

[0073] The forklift 1 according to the present embodiment is a counterbalanced forklift similar to the above embodiment. As shown in FIGS. 1 and 6, it includes a plurality of wheels 10, a vehicle body 11, a driver's seat 12, a head guard 13, a pedal 14, a lever 15, left and right masts 16, left and right forks 17, a speaker 19, a microphone 20, a weight change unit 21, a sound collection means 25, and a control unit 30.

[0074] The sound collection means 25 collects the ambient sound around the forklift 1. For example, the ambient sound includes the noise of working machines operating in the facility, such as presses. Note that the noise of working machines and presses is known to cause stress to people and reduce their concentration.

[0075] The weight change unit 21 changes the weights of the lever 15 and the pedal 14 during operation based on the command of the change command unit 306 (see FIG. 6) in the same manner as in the above embodiment. Similar to the above embodiment, the weight change unit 21 includes a pedal weight change unit that changes the weight of the pedal 14 and a lever weight change unit that operates the weight of the lever 15.

[0076] <Functional Configuration of the Third Embodiment> Next, the functional configuration of the weight change system S according to the third embodiment will be described. As shown in FIG. 6, the control unit 30 includes a storage unit 301, a volume reading unit 310, a stress level estimation unit 309, a weight determination unit 303, a change notification unit 304, a response reception unit 305, and a change command unit 306.

[0077] Similar to the above embodiment, the storage unit 301 stores the correspondence relationship between the stress level and the weights of the pedal 14 and the lever 15 corresponding thereto.

[0078] The volume reading unit 310 reads the volume of the ambient sound collected by the sound collection means 25.

[0079] The stress level estimation unit 309 estimates the stress level based on the volume of the ambient sound. The stress level estimation unit 309 estimates that the higher the volume of the noise, the higher the stress level, and the lower the volume of the noise, the lower the stress level.

[0080] Similar to the second embodiment, the weight determination unit 303 determines the weights of the pedal 14 and the lever 15 based on the estimated stress level and the weights of the pedal 14 and the lever 15 corresponding to the stress level stored in the storage unit 301.

[0081] Similar to the above embodiment, the change notification unit 304 notifies the driver H of the change in the weights of the pedal 14 and the lever 15 by voice from the speaker 19, and the response reception unit 305 receives a predetermined response from the driver H via the microphone 20 and transmits a response signal to the change command unit 306.

[0082] When receiving the response signal, the change instruction unit 306 controls the weight change unit 21 to change the weights of the pedal 14 and the lever 15 to the weights determined by the weight determination unit 303, similar to the above embodiment. Thereby, even if the concentration of the driver H fluctuates due to the stress related to noise, the weight change system S can change the weights of the pedal 14 and the lever 15 according to the stress level related to the volume of the noise.

[0083] <Flow of the weight change system according to the third embodiment> Next, while referring to the flowchart of FIG. 7, the operation of the weight change system S according to the third embodiment will be described again.

[0084] (1) First, the weight change system S reads the volume of the noise (see S71 in FIG. 7), and estimates the stress level based on the read volume of the noise (see S72 in FIG. 7).

[0085] (2) Next, the weight change system S determines the weights of the pedal 14 and the lever 15 with reference to the estimated stress level of the driver H (see S73 in FIG. 7).

[0086] (3) Next, the weight change system S determines that a change is necessary if the determined weights of the pedal 14 and the lever 15 are different from the weights of the pedal 14 and the lever 15 at that time (Yes in S74 of FIG. 7), and notifies the driver H of the change in the weights of the pedal 14 and the lever 15 (see S75 in FIG. 7).

[0087] (4) Next, when receiving the permission for the change from the driver H (Yes in S76 of FIG. 7), the weight change system S changes the weights of the pedal 14 and the lever 15 by the change instruction unit 306 (see S77 in FIG. 7). Also, until receiving the permission for the change from the driver H (No in S76 of FIG. 7), the weight change system S holds the change in the weights of the pedal 14 and the lever 15, and notifies the driver H of the change in the weight of the lever 15 again after a predetermined time.

[0088] As described above, the weight change system S according to the present embodiment changes the weights of the pedal 14 and the lever 15 based on the stress level related to the volume of noise that affects the level of the driver H's concentration. As a result, when the driver H has a high level of concentration, the operations of the pedal 14 and the lever 15 can be performed quickly, and when the driver H has a low level of concentration, major operation mistakes can be prevented.

[0089] <Fourth Embodiment> Next, a fourth embodiment of the weight change system according to the present invention will be described with reference to FIGS. 1, 8, and 9. The weight change system S according to the present embodiment is also configured to change the weights of both the pedal and the lever, similar to the above-described embodiment. Hereinafter, for the same configurations as those in the above-described embodiment, the same reference numerals may be given and the detailed description thereof may be omitted.

[0090] The forklift 1 according to the present embodiment is a counterbalanced forklift similar to the above-described embodiment, and as shown in FIGS. 1 and 8, includes a plurality of wheels 10, a vehicle body 11, a driver's seat 12, a head guard 13, a pedal 14, a lever 15, left and right masts 16, left and right forks 17, a camera 26, a speaker 19, a microphone 20, a weight change unit 21, and a control unit 30.

[0091] The camera 26 is fixed to the head guard 13, for example, and is configured to photograph the face of the driver H getting into the forklift 1 and generate a face image. The face image generated by the camera 26 is transmitted to the control unit 30.

[0092] The weight change unit 21 changes the weights of the lever 15 and the pedal 14 during operation based on a command from a change command unit 306 (see FIG. 8) by the same method as in the above-described embodiment. Similar to the above-described embodiment, the weight change unit 21 includes a pedal weight change unit that changes the weight of the pedal 14 and a lever weight change unit that operates the weight of the lever 15.

[0093] <Functional Configuration of the Fourth Embodiment> Next, the functional configuration of the weight change system S according to the fourth embodiment will be described. As shown in FIG. 8, the control unit 30 includes a storage unit 301, a driver identification unit 311, a stress level estimation unit 309, a weight determination unit 303, a change notification unit 304, a response reception unit 305, and a change command unit 306.

[0094] Similar to the above embodiment, the storage unit 301 stores the correspondence between the stress level and the weights of the pedal 14 and the lever 15 corresponding thereto. Further, the storage unit 301 stores face images and work schedules related to each of the plurality of drivers H. The work schedule includes at least one piece of information among the work amount per hour, the work area, the size of the work area, and the number of people in the work area. Note that the "size of the work area" is a quantification of the size or width of the area where the forklift 1 performs cargo handling work, such as the width of the passage of the forklift 1.

[0095] The driver identification unit 311 identifies the driver H who is about to board from among the plurality of drivers H stored in the storage unit 301 by referring to the face image generated by the camera 26 and the face images stored in the storage unit 301.

[0096] The stress level estimation unit 309 reads the schedule related to the identified driver H from the storage unit 301. Then, the stress level estimation unit 309 estimates the stress level of the driver H based on at least one piece of information among the work amount per hour, the work time in the same area, the size of the work area, and the number of people in the work area. Note that the stress level estimation unit 309 calculates the work time in the same area from the work area and work time included in the schedule.

[0097] The stress level estimation unit 309 may have a learned model that outputs the stress level of the driver H based on, for example, at least one piece of information among the work amount per hour (quota), the work time in the same area, the size of the work area, and the number of workers in the work area.

[0098] This learned model is machine - learned by teacher data that uses at least one of the information on the amount of work per unit time, the working time in the same area, the size of the working area, and the number of workers in the working area as input data and the stress level as output data. It is known that the higher the amount of work per unit time, the higher the stress level of driver H. Also, it is known that when the working time in the same area is long and the work becomes monotonous, or when the working area is narrow, the stress level of driver H increases. Furthermore, it is known that when the number of people in the working area increases, the possibility of contact with forklift 1 increases, so the stress level of driver H increases. The learned model has learned these correlations.

[0099] Accordingly, the learned model outputs a higher stress level as the input amount of work per unit time and the number of people in the working area increase. Also, the learned model outputs a higher stress level as the input working time in the same area becomes longer. Furthermore, the learned model outputs a higher stress level as the input size of the working area becomes narrower.

[0100] Therefore, the stress level estimation unit 309 estimates the stress level based on this learned model such that the higher the amount of work per unit time and the number of people in the working area, the longer the working time in the same area, and the narrower the size of the working area, the higher the stress level.

[0101] Similar to the above - described embodiment, the weight determination unit 303 determines the weights of the pedal 14 and the lever 15 based on the estimated stress level and the weights of the pedal 14 and the lever 15 corresponding to the stress level stored in the storage unit 301.

[0102] The change notification unit 304 notifies the driver H of the change in the weights of the pedal 14 and the lever 15 by voice from the speaker 19 in the same manner as in the above - described embodiment, and the response receiving unit 305 receives a predetermined response from the driver H via the microphone 20 and transmits a response signal to the change command unit 306 in the same manner as in the above - described embodiment.

[0103] When receiving the response signal, the change instruction unit 306 controls the weight change unit 21 to change the weights of the pedal 14 and the lever 15 to the weights determined by the weight determination unit 303 in the same manner as in the above embodiment. Thereby, even if the concentration of the driver H fluctuates due to stress related to at least one of the amount of work per unit time, the working time in the same area, the size of the working area, and the number of workers in the working area, the weight change system S can change the weights of the pedal 14 and the lever 15 according to the stress level.

[0104] <Flow of the weight change system according to the fourth embodiment> Next, with reference to the flowchart of FIG. 9, the operation of the weight change system S according to the fourth embodiment will be described again.

[0105] (1) First, the weight change system S identifies the driver H (see S91 in FIG. 9), reads the schedule (see S92 in FIG. 9), and estimates the stress level based on the read schedule (see S93 in FIG. 9).

[0106] (2) Next, the weight change system S determines the weights of the pedal 14 and the lever 15 with reference to the estimated stress level of the driver H (see S94 in FIG. 9).

[0107] (3) Next, if the weight change system S determines that the weights of the determined pedal 14 and lever 15 are different from the weights of the pedal 14 and lever 15 at that time (Yes in S95 of FIG. 9), it notifies the driver H of the change in the weights of the pedal 14 and lever 15 (see S96 in FIG. 9).

[0108] (4) Next, when the weight change system S receives permission for the change from the driver H (Yes in S97 of FIG. 9), the change instruction unit 306 changes the weights of the pedal 14 and the lever 15 (see S98 of FIG. 9). Further, until the weight change system S receives permission for the change from the driver H (No in S97 of FIG. 9), the weight change of the pedal 14 and the lever 15 is suspended, and the driver H is notified again of the weight change of the lever 15 after a predetermined time has elapsed.

[0109] As described above, the weight change system S according to the present embodiment changes the weights of the pedal 14 and the lever 15 based on at least one of the workload per unit time that affects the driver H's concentration, the working time in the same area, the size of the working area, and the stress level related to the number of workers in the working area. As a result, when the driver H has a high concentration, the operations of the pedal 14 and the lever 15 can be performed quickly, and when the driver H has a low concentration, large operation mistakes can be prevented.

[0110] As described above, each embodiment of the weight change system according to the present invention has been described. However, the present invention is not limited to the above embodiments. The weight change system according to the present invention may be implemented, for example, by combining the above embodiments, or by implementing each of the following modification examples or by combining the modification examples.

[0111] <Modification Example> · The forklift 1 may be a reach forklift. In this case, the pedal 14 may include a presence pedal. Further, the forklift 1 may be an engine-driven forklift. In this case, the pedal 14 may include a clutch pedal. Furthermore, when the forklift 1 is a reach forklift, the lever 15 may include an accelerator lever. Also, as described above, the "pedal" in the present invention includes at least one of the above pedals, the "lever" includes at least one of the above levers, and the weight change system according to the present invention changes the weight of at least one of the above lever and pedal.

[0112] ·Any configuration of the control unit 30 may be configured by, for example, a server computer provided on the cloud. In this case, the weight change system S changes the weight of the pedal 14 and the lever 15 or any of them by communicating with this server computer.

[0113] ·The method for identifying the driver H by the driver identification unit 311 is not particularly limited. For example, the driver identification unit 311 may read a card or the like possessed by each driver H to identify each driver H.

[0114] ·The forklift 1 is provided with a monitor instead of the speaker 19, and the change notice unit 304 may notify the change of the weight of the lever 15 and the pedal 14 or any of them by this monitor.

[0115] ·The forklift 1 is provided with a button instead of the microphone 20, and the response receiving unit 305 may receive the response from the driver H via the button.

[0116] ·The weight determination unit 303 may determine the weight of the pedal 14 and the lever 15 or any of them based on the total value of each stress level, such as when implementing a combination of embodiments.

Explanation of Reference Numerals

[0117] S Weight change system H Driver 1 Forklift 10 Wheels 11 Vehicle body 12 Driver's seat 13 Head guard 14 Pedal 15 Lever 16 Mast 17 Fork 19 Speaker 20 Microphone 21 Weight change unit 22 Stress level estimation means 23 Thermometer 24 Humidity meter 25 Sound collection means 26 Camera 30 Control unit 301 Memory unit 302 Stress level reading unit 303 Weight determination unit 304 Change notice unit 305 Response receiving unit 306 Change command unit 307 Temperature and humidity reading unit 308 Discomfort index calculation unit 309 Stress level estimation unit 310 Volume reading unit 311 Driver identification unit

Claims

1. A weight change system for use in a forklift, comprising: a weight change unit that changes the weight of the pedal and lever of the forklift or either of them; a change command unit that controls the weight change unit according to the stress level of the driver to change the weight of the pedal and lever or either of them.

2. The weight change system according to claim 1, further comprising stress level estimation means for estimating the stress level of the driver.

3. temperature and humidity measurement means for measuring temperature and humidity; a discomfort index calculation unit for calculating a discomfort index from the temperature and humidity; a stress level estimation unit for estimating the stress level of the driver based on the calculated discomfort index, wherein the change command unit changes the weight of the pedal and lever or either of them according to the estimated stress level of the driver.

4. sound collection means for collecting ambient sound; a stress level estimation unit for estimating the stress level of the driver based on the volume of the ambient sound, wherein the change command unit changes the weight of the pedal and lever or either of them according to the estimated stress level of the driver.

5. a storage unit for storing the work schedule of the driver including the amount of work per hour; a stress level estimation unit for referring to the work schedule and estimating the stress level of the driver according to the amount of work per hour, wherein the change command unit changes the weight of the pedal and lever or either of them according to the estimated stress level of the driver.

6. a storage unit for storing the work schedule of the driver including the amount of work in the same area; a stress level estimation unit for referring to the work schedule and estimating the stress level of the driver according to the amount of work in the same area, wherein the change command unit changes the weight of the pedal and lever or either of them according to the estimated stress level of the driver.

7. a storage unit for storing the work schedule of the driver including the size of the work area A stress level estimation unit that refers to the work schedule and estimates the stress level of the driver according to the size of the work area; The weight change system according to claim 1, wherein the change command unit changes the weight of the pedal and the lever or either of them according to the estimated stress level of the driver.

8. A storage unit that stores the work schedule of the driver including the number of people in the work area; A stress level estimation unit that refers to the work schedule and estimates the stress level of the driver according to the number of people in the work area; The weight change system according to claim 1, wherein the change command unit changes the weight of the pedal and the lever or either of them according to the estimated stress level of the driver.

9. Further comprising a stress level estimation unit that estimates the stress level of the driver based on at least one piece of information among the amount of work per hour, the working time in the same area, the size of the work area, and the number of people in the work area; The weight change system according to claim 1, wherein the change command unit changes the weight of the pedal and the lever or either of them according to the estimated stress level of the driver.

10. A forklift equipped with the weight change system according to any one of claims 1 to 9.

11. A program used in a weight change system comprising a weight change unit that changes the weight of the pedal and the lever of a forklift or either of them, and a computer, A weight change program that controls the weight change unit according to the stress level of the driver to change the weight of the pedal and the lever or either of them in the computer.

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