JP2546435Y2 - Forklift with electric tilt mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forklift having a tilting fork.

[0002]

2. Description of the Related Art Conventionally, in a reach-type forklift, when a load is conveyed or a fork on which the load is loaded is lifted or lowered, the load may fall off the fork due to centrifugal force or inertia. In order to prevent this, some tilt operation is performed. This tilt operation is to incline the fork toward the vehicle body by a predetermined angle immediately after placing the load on the fork, and as a result, the load tilts toward the vehicle body, and a slight centrifugal force or Even if an inertial force is generated, the load can stably operate without dropping forward and sideways.

A mechanism for the tilt operation will be described below. FIG. 6 is a side view showing the entire configuration of a general reach-type forklift. In the front part of the forklift 1, a fork 2 for mounting a load is held by a lift bracket 3. The lift bracket 3 is mounted on the mast 4 so as to be able to move up and down, and the fork 2 is moved up and down by raising or lowering the bracket 3. Tilt cylinders 5a and 5b driven by hydraulic pressure are provided on both left and right sides of the lift bracket 3, and a hose 6 for supplying oil to the tilt cylinders 5a and 5b is provided on the mast 4.

FIG. 7 is an exploded perspective view showing a detailed structure of the fork 2 and the lift bracket 3. The lift bracket 3 has left and right side plates 31a, 31b provided in parallel with the mast 4 (FIG. 6), a support 32 integrated therewith, a fork shaft 33 for mooring and holding the fork 2, and a plate 34a. Tilt frame 3
And 4. The side plate 31a,
Tilt cylinders 5a and 5b for pushing the plate 34a are provided inside 31b. Hydraulic hoses 6a, 6 are attached to the tilt cylinders 5a, 5b.
When the oil is sent through the b, the tilt shafts 51a and 51b project in the longitudinal direction by the oil pressure. At the upper end of the fork 2, a pipe 21
a, 21b are provided, and by inserting the fork shaft 33 through the pipes 21a, 21b, the fork 2 is moored to be rotatable in the front-rear direction. Further, left and right ends 33a, 33b of the fork shaft 33 are provided with holes 32a, 3 provided on the left and right side surfaces of the support 32, respectively.
2b.

With the above arrangement, the tilt cylinder 5
When hydraulic pressure is supplied to a and 5b, the tilt shaft 51
The plate 34a of the tilt frame 34 is pushed by the protrusions a and 51b. As a result, the tilt frame 34 presses the fork 2 while rotating forward around the fork shaft 33, and performs a tilt operation as indicated by an arrow in FIG.

[0006]

However, in the conventional forklift described above, in order to drive the tilt mechanism, hydraulic pressure is generated by a pump and a motor provided on the vehicle body side, and the hydraulic pressure is generated via the hoses 6a and 6b. And transmitted to the tilt cylinders 5a and 5b. As shown in FIG. 8, the hose used for transmitting the hydraulic pressure is often mounted on the mast 4.
Since a certain thickness is required, the driver's view may be hindered, and improvement in safety is desired. Further, the hose itself may be damaged due to wear, causing oil leakage or the like, resulting in contamination of the load.

The present invention solves the above-mentioned problems. The tilt mechanism is constructed without using a masted hose, the driver has a good view, and oil leakage from the hose causes an oil leak. An object of the present invention is to provide a forklift that does not stain a load.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a forklift having a tilting fork, an electric motor serving as a driving source of the tilting operation, and a drive of the electric motor being applied to the fork. And a large-capacity capacitor charged by a small current from a main battery and supplying power to the electric motor.

[0009]

According to the above arrangement, the large-capacity capacitor is charged with a small current from the main battery, and the electric motor is operated by being supplied with power from the large-capacity capacitor to the electric motor. The driving force of the electric motor is transmitted to the fork by the drive transmission means, and the fork performs a tilt operation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing the overall configuration of the reach type forklift according to the present embodiment. In the figure, a fork 2 for mounting a load is provided at a front portion of a forklift 1. This fork 2
Is moored and held by a lift bracket 3, and the lift bracket 3 is mounted on a mast 4 so as to be able to move up and down. The fork 2 is raised and lowered by lifting or lowering the lift bracket 3 along the mast 4. Further, in order to cause the fork 2 to perform a tilt operation, electric tilt cylinders 5 a and 5 b and a drive circuit 8 thereof are provided inside the lift bracket 3. On the other hand, on the vehicle body side, a vehicle body side circuit 9 having a battery is provided.
And is connected to the drive circuit 8 via a signal line 10.

FIG. 2 is an exploded perspective view showing a detailed structure of the fork 2 and the lift bracket 3. As shown in FIG. The lift bracket 3 includes left and right side plates 31a and 31b provided in parallel with the mast 4, and a support 32 integrated therewith.
And a tilt frame 34 having a fork shaft 33 for mooring and holding the fork 2 and a plate 34a. Tilt cylinders 5a, 5b for pushing the plate 34a are provided inside the side plates 31a, 31b. The tilt cylinders 5a and 5b are of a hydraulic type in the above-described conventional example, but are mounted in the present embodiment by those driven by an electric motor. That is, power is supplied from a battery mounted on the vehicle body via the signal line 10, and the power is charged by the drive circuit 8. Then, when a tilt operation command is issued, the drive circuit 8 supplies power to the electric motors of the tilt cylinders 5a and 5b in response to the tilt operation command, and the tilt shafts 51a and 51b are protruded in the longitudinal direction by the rotation. The detailed configuration of the tilt cylinders 5a and 5b will be described later.

At the upper end of the fork 2, a pipe 21a,
21b is provided, and by inserting the fork shaft 33 through the pipes 21a and 21b, the fork 2 is moored so as to be rotatable in the front-rear direction. Further, the left and right ends 33a, 33b of the fork shaft 33 are provided with holes 32a, 32 provided on the left and right side surfaces of the support 32, respectively.
b, the support 32 and the tilt frame 34
And are assembled.

FIG. 3 shows the tilt cylinders 5a and 5b.
It is a perspective view which shows the detailed structure of. Since the structures of the cylinder 5a and the cylinder 5b are equivalent, only the cylinder 5a is illustrated. As described above, the tilt cylinder 5a is provided with the cylindrical shaft 51a. The shaft 51a is supported so as to be able to protrude and retract in the longitudinal direction while being prevented from rotating with respect to the tilt cylinder 5a. A female screw 52 is formed on the inner diameter side of the shaft 51a, and a male screw 53 corresponding to the female screw 52 is inserted.
A ball is inserted between the female screw 52 and the male screw 53,
The ball screw is constituted by both. A driven gear 54 for rotating the male screw 53 is fixed to one end of the male screw 53. The driven gear 54 is rotated by an electric motor 57 via a drive transmission gear 55 and a drive gear 56. Driven. The electric motor 57 operates by energization from a drive circuit 8 described later.

FIG. 4 is a configuration diagram of the drive circuit 8 of the electric motor 57. The drive circuit 8 includes a large-capacity capacitor C1, four transistors T1, T2, T3, and T4, and a tilt controller 81, and a vehicle-body-side circuit including a main battery 91 and a chopper unit 92 via a signal line 10. 9 is connected.

With the above configuration, the capacitor C1 of the drive circuit 8 is charged from the main battery 91 of the vehicle body side circuit 9 via the signal line 10, and the transistors T1, T2, T3, and T4 are activated by a signal from the tilt controller 81. Under the respective controls, the electric motor 57 is energized in a predetermined direction, and the electric motor 57 rotates. For example, the driving gear 56
Rotates in the direction of arrow A, the drive transmission gear 55 rotates in the direction of arrow B in conjunction therewith, and further the driven gear 54
Rotates in the direction of arrow C. The engagement of the male screw 53 and the female screw 52 causes the shaft 51a to protrude in the direction of arrow D, and causes the plate 34a of the tilt frame 34 to move in the direction of arrow E.
Push in the direction. This causes the fork 2 to tilt as indicated by the arrow in FIG. On the other hand, when the electric motor 57 is energized in the opposite direction under the control of the tilt controller 81, the gears 56, 55, 5
4 rotate in the directions opposite to the arrows A, B and C, respectively.
The shaft 51a is pulled into the cylinder 5a, and the fork 2 returns to a horizontal state.

Normally, the tilt operation time is extremely short, and if the operation / non-operation time is averaged, the power required for the tilt operation is small. Therefore, the main battery 91 of the vehicle body side circuit 9
As described above, a wire for supplying a current to the capacitor C1 of the drive circuit 8 from the signal line 10 is sufficient.
In a forklift equipped with a conventional hydraulic tilt mechanism, a thick hydraulic hose was mounted on the mast, which hindered the driver's view.However, the electric tilt mechanism according to the present embodiment includes: Since a thin signal line is masted, the field of view is widened and safety is improved. Also,
There is no problem that the hose is damaged by abrasion or the like, and oil leaks from the inside and the load on the lift becomes dirty.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described configuration, and various modifications and applications can be made. For example, as the charging mechanism provided in the drive circuit 8, a battery or the like may be provided instead of the capacitor C1. Also, as shown in FIG.
1 is connected to a generator 42 so that the capacitor C1 of the drive circuit 8 is charged when the fork 2 moves up and down, and a command signal (shown by a broken line) is transmitted from the vehicle body by wireless or off-line means such as light. With such a configuration, the signal line 10 for transmitting power from the vehicle body is not required.

[0018]

[Effect of the Invention] As described above, according to the present invention, the provision of the electric tilt mechanism eliminates the necessity of a structure in which the hydraulic hose is mounted on the mast, thereby increasing the driver's view. The operability and safety are improved. Further, conventionally, the hydraulic hose was damaged due to abrasion or the like, and oil leaked from the inside to contaminate the load, but the forklift of the present invention eliminates such a problem.

[Brief description of the drawings]

FIG. 1 is a side view showing an overall configuration of a forklift according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a lift bracket and a fork mounted on the forklift.

FIG. 3 is a configuration diagram of an electric tilt cylinder mounted on the forklift.

FIG. 4 is a configuration diagram of a drive circuit of an electric tilt cylinder mounted on the forklift.

FIG. 5 is a side view showing a configuration of a forklift including a power generation mechanism and an off-line drive command transmission unit.

FIG. 6 is a side view showing the entire configuration of a conventional forklift.

FIG. 7 is an exploded perspective view of a lift bracket and a fork mounted on the forklift.

FIG. 8 is a perspective view of a mast of the forklift.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Forklift 2 Fork 5a, 5b Tilt cylinder 8 Drive circuit 51a, 51b Tilt shaft 52 Ball screw (male screw) 53 Ball screw (male screw) 54 Driven gear 55 Drive transmission gear 56 Drive gear 57 Electric motor 91 Main battery C1 Large capacity capacitor

Claims (1)

(57) [Scope of request for utility model registration] 1. A forklift having a tilting fork, an electric motor serving as a driving source of the tilting operation, a drive transmitting means for transmitting the driving of the electric motor to the fork, and a small current charged from a main battery. And a large-capacity capacitor for supplying power to the electric motor.