JP7311237B2 - Forklift with spreader damage prevention function - Google Patents

Description

The present invention relates to a forklift equipped with a spreader breakage prevention function.

Conventionally, there is a forklift that carries an empty container, as disclosed in Patent Document 1. This forklift has a spreader, and the spreader has rails extending left and right, supports provided at both ends of the rails, and twist lock pins provided on the supports. When transporting a container, the forklift first advances toward the container to bring the column close to or in contact with the container, then inserts the twist lock pin into the locking hole at the corner of the upper surface of the container and rotates it to the container. lock it. The forklift lifts and transports the container while the twist lock pin is engaged with the container.

By the way, when the column is brought close to the container, the user visually confirms the distance between the column and the container. However, if this visual observation is incorrect, there is a risk that the struts will be pressed against the container too much by the forward movement of the vehicle body, damaging the spreader. Moreover, since it is not possible to visually determine whether the container is empty or not, if the container to be lifted is a full container, there is a risk that the spreader will be damaged due to overloading.

JP 2006-321634 A

Therefore, the problem to be solved by the present invention is to provide a forklift equipped with a spreader breakage prevention function capable of preventing breakage of the spreader, which is difficult to prevent visually during container transportation.

In order to solve the above problems, a forklift equipped with a spreader breakage prevention function according to the present invention includes:
a vehicle body;
a mast extending vertically in front of the vehicle body;
a spreader that is raised and lowered along the mast;
a control unit;
The spreader is
a rail extending in the left-right direction;
a pair of left and right struts provided at the left and right ends of the rail and extending in the vertical direction;
a predetermined distance detection unit that detects whether or not the distance between the front surfaces of the pair of left and right pillars and another object is within a predetermined distance;
a locking portion provided on each of the pair of left and right pillars and locked to the container;
a locking detection unit that detects whether or not the locking unit is locked to the container;
When the predetermined distance detection unit detects that the distance between the front surfaces of the pair of left and right struts and another object is within a predetermined distance, the control unit stops forward movement of the vehicle body, and the locking detection unit detects that the locking unit is engaged. The stop of the forward movement is released when it is detected that the container is locked.

The forklift preferably comprises
A predetermined distance detection unit is a proximity sensor and is provided on the support.

The forklift preferably comprises
a lift cylinder that expands and contracts with hydraulic oil to raise and lower the rail;
a tank containing hydraulic oil;
a hydraulic oil supply/discharge path provided between the lift cylinder and the tank; and a control valve provided in the supply/discharge path for controlling the operation of the lift cylinder;
a pressure sensor that detects the hydraulic pressure of the supply and discharge passages and detects whether or not the container lifted by the lift cylinder has a predetermined weight or more;
and a control valve stop unit for stopping the operation of the control valve to stop the extension of the lift cylinder when the container lifted by the lift cylinder is a container of a predetermined weight or more.

The forklift preferably comprises
the control valve stop is a solenoid valve,
A solenoid valve is installed in the supply and discharge passage between the tank and the control valve,
Hydraulic oil is supplied to the lift cylinder via the control valve via a solenoid valve.
The solenoid valve cuts off the supply of hydraulic oil from the tank to the control valve when the container lifted by the lift cylinder is of a predetermined weight or more.

The forklift according to the present invention can prevent breakage of the forklift, which is difficult to prevent visually during container transportation.

1 is a side view of a forklift according to one embodiment of the present invention; FIG. 2 is a front view of the forklift shown in FIG. 1; FIG. A is a side view schematically showing the inside of each configuration of section D in FIG. 1, and B is a plan view schematically showing the inside of a cylinder box. FIG. 2 is a view showing part of the hydraulic system of the forklift shown in FIG. 1; 2 is a functional block diagram of each configuration of the forklift shown in FIG. 1; FIG. 2 is an electrical circuit diagram of the forklift shown in FIG. 1; FIG. FIG. 2 is a flow diagram of a spreader breakage prevention function of the forklift shown in FIG. 1;

An embodiment of a forklift equipped with a spreader breakage prevention function of the present invention will be described below with reference to the accompanying drawings. In the drawings, a double-headed arrow X indicates the front-rear direction, a double-headed arrow Y indicates the left-right direction, and a double-headed arrow Z indicates the up-down direction.

As shown in FIGS. 1 and 2, a forklift F according to the present embodiment includes front and rear wheels 1, a vehicle body 2 supported by the wheels 1, a driver's seat 3 provided above the vehicle body 2, and a vehicle body 2. , a carriage 5, a spreader 6, a pair of left and right lift cylinders 7, and a control unit 8.

A pair of left and right masts 4 extend vertically, and a spreader 6 is connected to the masts 4 via a carriage 5 . The spreader 6 is moved up and down along the mast 4 by a pair of left and right lift cylinders 7 .

As shown in FIGS. 2 and 3, the spreader 6 includes rails 60 (60a, 60b), a pair of left and right struts 62, a twist lock pin 63, a predetermined distance detector 64, a lock detector 65, have

The rail 60 has a fixed rail 60a that does not expand and contract, and a pair of left and right expandable rails 60b that expand and contract in the left and right direction from left and right ends of the fixed rail 60a. The fixed rail 60 a is connected to the mast 4 via the carriage 5 .

As shown in FIGS. 3A and 3B, the pair of left and right struts 62 has a strut body 62a, a cylinder box 62b, a twist lock cylinder 62c, a twist lock holder 62d, and a cam 62e.

The left and right column main bodies 62a extend in the vertical direction and are connected to the outer ends of the expandable rails 60b, respectively. The cylinder box 62b is provided above the column body 62a.

The twist lock cylinder 62c extends in the front-rear direction and is provided inside the cylinder box 62b. The twist lock cylinder 62c is a hydraulic cylinder, and is extended and contracted in the front-rear direction by hydraulic pressure. The twist lock holder 62d extends vertically and is connected to the twist lock cylinder 62c via a cam 62e. As shown in FIGS. 3A and 3B, the twist lock cylinder 62c expands and contracts to rotate the twist lock holder 62d by 90 degrees.

The twist lock pin 63 is fixed to the lower end of the twist lock holder 62d. The twist lock pin 63 is tapered toward the lower end and has an overhanging portion 63a horizontally overhanging the twist lock holder 62d as indicated by a two-dot chain line. The twist lock pin 63 corresponds to the "locking portion" of the present invention. As shown in FIG. 3A, the twist lock pin 63 is rotated by 90° together with the twist lock holder 62d by extension and contraction of the twist lock cylinder 62c. As a result, the twist lock pin 63 is locked to or unlocked from the locking hole Wh provided in the container W. As shown in FIG.

As shown in FIG. 3A, the predetermined distance detector 64 is a proximity sensor and is embedded in each of the left and right pillars 62 . The predetermined distance detection unit 64 detects whether or not the distance P between the front surfaces of the left and right supports 62 and another object is within a predetermined distance. The predetermined distance may be set between 0 mm and 10 mm, for example. Thereby, the predetermined distance detection unit 64 can detect the proximity or contact between the container W and the support column 62 before the support column 62 is pressed against the container W.

The locking detector 65 has two proximity sensors 65a and 65b in this embodiment. As shown in FIGS. 3A and 3B, the two proximity sensors 65a and 65b are spaced apart from each other in the longitudinal direction inside the cylinder box 62b and above the twist lock holder 62d. A detection plate 65c having an inverted L shape in a plan view is provided on the upper surface of the twist lock cylinder 62c, and the detection plate 65c is slid in the front-rear direction by expansion and contraction of the twist lock cylinder 62c. The locking detector 65 detects the extension/contraction state of the twist lock pin 63 based on which of the two proximity sensors 65a and 65b is detecting the detection plate 65c. Thereby, the locking detector 65 detects the orientation of the twist lock pin 63 and thereby detects whether the twist lock pin 63 is locked to the container W or not.

FIG. 4 shows a partial configuration of the hydraulic system of the forklift F according to this embodiment. As shown in FIG. 4 , the forklift F further includes a tank 9 , a supply/discharge path 10 , a pilot valve 11 , a control valve 12 , a solenoid valve 13 and a pressure sensor 14 .

The tank 9 contains working oil. A supply/discharge passage 10 is provided between the tank 9 and the lift cylinder 7 , and hydraulic oil is supplied to the lift cylinder 7 through the supply/discharge passage 10 .

The pilot valve 11 switches supply and discharge of hydraulic oil to the control valve 12 based on the operation of an operation unit 30 (see FIG. 5) provided in the driver's seat 3 .

The solenoid valve 13 is provided in the supply/discharge path 10 between the pilot valve 11 and the tank 9 and the control valve 12 , and opens and closes the supply/discharge path 10 from the pilot valve 11 and the tank 9 to the control valve 12 .

The control valve 12 switches supply and discharge of hydraulic oil supplied to the lift cylinder 7 based on the supply of hydraulic oil via the pilot valve 11 . In other words, the control valve 12 cannot operate when the supply of hydraulic oil via the pilot valve 11 is stopped by the solenoid valve 13 .

The pressure sensor 14 is provided in the vicinity of the supply/discharge passage 10 between the lift cylinder 7 and the control valve 12, detects the hydraulic pressure in the supply/discharge passage 10, and detects whether or not this hydraulic pressure is equal to or higher than a predetermined hydraulic pressure. Thereby, the pressure sensor 14 detects whether the container W lifted by the lift cylinder 7 has a predetermined weight or more.

The predetermined hydraulic pressure is set to the hydraulic pressure when the forklift F lifts the container W having a predetermined weight. That is, when the pressure sensor 14 detects an oil pressure equal to or higher than a predetermined oil pressure, the forklift F is lifting a container W having a weight equal to or higher than the predetermined weight. The predetermined weight may be, for example, 6,000 kg.

FIG. 5 is a functional block diagram of each component of the forklift F. As shown in FIG. As shown in FIG. 5, the forklift F further includes a forward control valve 15 and a transmission 16. As shown in FIG. FIG. 6 is an electric circuit diagram showing a part of the configuration of the control section 8. As shown in FIG. As shown in FIG. 6, the control unit 8 includes a forward control solenoid 80, a reverse control solenoid 81, three relays 82, 83, 84, a predetermined distance detector switch 85, a locking detector switch 86, and a pressure switch 87 . The directions of the three relays 82, 83, and 84 in FIG. 6 are the directions when the excitation coils of the respective relays are not energized.

The transmission 16 can switch between forward, neutral and reverse based on hydraulic control. This hydraulic control is performed via a forward control valve 15 and a reverse control valve (not shown). A forward control solenoid 80 controls the forward control valve 15, and a reverse control solenoid 81 controls the reverse control valve.

As shown in FIG. 5 , the control unit 8 receives outputs from the predetermined distance detection unit 64 , locking detection unit 65 and pressure sensor 14 . When the predetermined distance detection unit 64 detects that the distance P between the front surface of the column 62 and the container W is less than the predetermined distance, the control unit 8 cuts off the energization of the forward control solenoid 80 and operates the forward control valve 15 . stop. More details will be described with reference to FIG.

As shown in FIG. 6 , when the operation unit 30 is switched to forward (F), current flows through the forward control solenoid 80 and the relay 82 , activating the forward control solenoid 80 . At this time, when the predetermined distance detector 64 detects that the distance P between the front surface of either the left or right column 62 and the container W is less than or equal to the predetermined distance, the predetermined distance detector switch 85 is turned on and the exciting coil of the relay 82 is turned on. , and the relay 82 is switched to the terminal on the side of the predetermined distance detecting section switch 85 (upper terminal). As a result, the forward control solenoid 80 is opened and deenergized, and as a result, forward movement of the forklift F is stopped. As a result, the forklift F can prevent the spreader 6 from being damaged by the user U accidentally pushing the support column 62 against the container W too much.

Subsequently, when the lock detection unit 65 detects that the twist lock pin 63 is locked to the container W, the control unit 8 resumes energization of the forward control solenoid 80 . More specifically, with reference to FIG. 6, when the lock detector 65 detects that the twist lock pin 63 is locked to the container W, the lock detector switch 86 is turned on and the excitation coil of the relay 83 is turned on. , and the relay 83 is switched to the terminal (upper terminal) on the lock detector switch 86 side. As a result, the energization of the excitation coil of the relay 82 is interrupted, and the relay 82 is switched to the opposite side terminal (lower side terminal) of the predetermined distance detecting section switch 85 side terminal. As a result, the forward control solenoid 80 is energized again, and as a result, the forward stop of the forklift F is released.

Furthermore, when the pressure sensor 14 detects an oil pressure equal to or higher than a predetermined oil pressure, the control unit 8 cuts off the energization of the solenoid valve 13 . 6, when the pressure sensor 14 detects an oil pressure equal to or higher than a predetermined oil pressure, the pressure switch 87 is turned ON, current flows through the excitation coil of the relay 84, and the relay 84 is activated by the pressure switch 87. side terminal (upper terminal). As a result, the solenoid valve 13 is opened and the energization to the solenoid valve 13 is cut off. As a result, the solenoid valve 13 closes the supply/discharge path 10 and stops the supply of hydraulic oil to the control valve 12 via the pilot valve 11, thereby stopping the operation of the control valve 12. As a result, the extension of the lift cylinder 7 is stopped, so that the forklift F can prevent the spreader 6 from being damaged when the user U tries to lift the filled container W with the forklift F. At this time, as shown in FIG. 6, the control unit 8 further has a warning buzzer 88 and a warning lamp 89. When the pressure switch 87 is turned on, the warning buzzer 88 and the warning lamp 89 are energized, and the warning buzzer The user U may be notified by voice of 88 and light of warning lamp 89 .

Next, with reference to the flowchart of FIG. 7, the spreader breakage prevention function of the forklift F during transportation of the container W will be described.

(1) To transport the container W, the forklift F moves forward toward the container W while the twist lock pin 63 is raised above the container W (step S1).

(2) When the predetermined distance detection unit 64 detects that the distance P between the front surface of the column 62 and the container W is within the predetermined distance (Yes in step S2), the forklift F is stopped by the control unit 8. (Step S3).

(3) Next, the forklift F lowers the spreader 6 to insert the twist lock pin 63 into the locking hole Wh of the container W, and rotates the twist lock pin 63 to lock the container W. When the lock detector 65 detects that the twist lock pin 63 is locked to the container W (Yes in step S4), the forward stop of the forklift F is released (step S5).

(4) Next, the forklift F lifts the container W with the lift cylinder 7 (step S6).

(5) Next, if the pressure sensor 14 does not detect a container W weighing a predetermined weight or more (No in step S7), the forklift F lifts the container W to a predetermined height and completes the lift operation (step S8). On the other hand, when the pressure sensor 14 detects a container W having a predetermined weight or more, the control unit 8 stops the lift operation by the lift cylinder 7 of the forklift F.

Since the forklift F has the spreader breakage prevention function, the support 62 can be appropriately brought close to the container W without relying on the user U's visual observation. By stopping the operation, damage to the spreader 6 due to overload can be prevented.

Although the forklift F according to one embodiment of the present invention has been described above, the forklift according to the present invention is not limited to the above embodiment. For example, the control unit 8 according to the present invention may stop or cancel forward movement of the vehicle body 2 or stop extension and retraction of the lift cylinder 7 by other known techniques.

F Forklift W Container Wh Locking hole U User 1 Wheel 2 Car body 3 Driver's seat 30 Operation part 4 Mast 5 Carriage 6 Spreader 60 Rail 60a Fixed rail 60b Telescopic rail 62 Support 62a Support main body 62b Cylinder box 62c Twist lock cylinder 62d Twist lock holder 62e Cam 63 Twist lock pin (locking portion)
64 predetermined distance detector 65 lock detector 65a, 65b proximity sensor 65c detection plate 7 lift cylinder 8 controller 80 forward control solenoid 81 reverse control solenoid 82, 83, 84 relay 85 predetermined distance detector switch 86 lock detector switch 87 pressure switch 88 warning buzzer 89 warning lamp 9 tank 10 supply and discharge passage 11 pilot valve 12 control valve 13 solenoid valve 14 pressure sensor 15 forward control valve 16 transmission

Claims (4)

a vehicle body;
a mast extending vertically in front of the vehicle body;
a spreader that is raised and lowered along the mast;
a control unit;
The spreader is
a rail extending in the left-right direction;
a pair of left and right struts respectively provided at left and right ends of the rail and extending in the vertical direction;
a predetermined distance detection unit that detects whether or not the distance between the front surfaces of the pair of left and right pillars and another object is within a predetermined distance;
a locking portion provided on each of the pair of left and right pillars and locked to the container;
a locking detection unit that detects whether or not the locking unit is locked to the container;
The control unit stops forward movement of the vehicle body when the predetermined distance detection unit detects that the distance between the front surfaces of the pair of left and right struts and another object is within a predetermined distance, and stops the vehicle body from moving forward. a forklift equipped with a spreader breakage prevention function, wherein the stopping of the forward movement is released when it is detected that the locking portion is locked to the container by a. 2. The forklift truck according to claim 1, wherein the predetermined distance detection unit is a proximity sensor and is provided on the column. a lift cylinder that expands and contracts with hydraulic oil to raise and lower the rail;
a tank containing the hydraulic oil;
a hydraulic oil supply/discharge path provided between the lift cylinder and the tank; a control valve provided in the supply/discharge path for controlling the operation of the lift cylinder;
a pressure sensor that detects the hydraulic pressure of the supply/discharge path and detects whether or not the container lifted by the lift cylinder has a predetermined weight or more;
a control valve stop unit for stopping the operation of the control valve to stop the extension of the lift cylinder when the container lifted by the lift cylinder is a container having a predetermined weight or more. A forklift according to claim 1 or 2. The control valve stop portion is a solenoid valve,
The solenoid valve is provided in the supply/discharge path between the tank and the control valve,
supply of the hydraulic oil to the lift cylinder via the control valve is performed via the solenoid valve;
4. The solenoid valve according to claim 3, wherein the solenoid valve cuts off the supply of the hydraulic oil from the tank to the control valve when the container lifted by the lift cylinder has a predetermined weight or more. forklift.

Images