JPH0858598A - Hand truck - Google Patents

Abstract

PURPOSE: To provide a hand truck for operation with less fatigue by varying running speed of the hand truck optionally according to walking speed of an operator. CONSTITUTION: A hand truck comprises a pressure detecting part 6 for detecting and outputting force applied to handles 7a, 7b as electric signals, an adder for adding the outputted voltage of this pressure detecting part 6 and reference voltage and a subtracter for subtracting and outputting the output signal of the adder and a feedback signal. The hand truck has an amplifier for outputting an output signal of the subtracter to the motor 3 after amplifying it and a drive wheel 1 directly coupled to the motor for rotation and a tacho-generator 14 for detecting rotational frequency of the motor 3 as the electric signal and outputting it to the subtracter as a feedback signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hand truck used in factories, stores, facilities and the like.

[0002]

2. Description of the Related Art FIGS. 7A and 7B respectively show
It is a perspective view and a partial cutting front view showing the example of composition of the conventional hand truck. In this figure, reference numeral 1 is a drive wheel, which is fixed to a drive wheel shaft 2. The drive wheel shaft 2 is rotatably provided on the bearing 4 and is driven by the motor 3.
Reference numeral 5 denotes a handle shaft, which is connected to the shaft 5a through a flexible joint 7 and is rotatably attached to the carriage main body 9. Reference numerals 7a and 7b are handles, which rotate in the left-right direction to change the traveling direction D of the hand cart. Reference numeral 9a is a luggage carrier. Two follower wheels (FIG. 2B) are provided below the luggage carrier 9a. Reference numeral 12 is an operation unit, and an enlarged view is shown in FIG. In this figure, reference numeral 12a is a "power supply" lever for turning off / on the power supply, reference numeral 12b is a "forward / reverse" lever for selecting forward and reverse movements, and reference numeral 12c is a three-step speed and stop. This is the "travel speed" lever to select. In addition,
As shown in FIG. 8B, a switch may be provided instead of the operation lever.

The operation of the hand cart having the above structure will be described. First, the operator uses the operation unit 12 to select "travel speed".
To the stop position. Next, after turning on the power with the "power" turned on, the "forward / reverse" is set to the forward position. Then, the forward running is started at the selected predetermined speed by setting the "running speed" to any of the high speed, the medium speed, and the low speed.

[0004]

By the way, in the above-mentioned conventional hand cart, the traveling speed is set in three stages (high speed,
Since it can be set only to medium speed and low speed, when the traveling speed of the trolley is slower than the walking speed of the operator, the operator must follow with slow foot (stepping state). Further, when the set speed of the truck is faster than the walking speed of the operator, the operator must follow the truck with a fast foot. This is especially true when traveling long distances
There is a drawback that the operator is painful.

The present invention has been made under such a background, and an object thereof is to provide a hand truck which can adjust the traveling speed of the hand truck to the walking speed of the operator.

[0006]

According to the first aspect of the present invention,
In a hand-pushed trolley having a trolley body, drive means for driving drive wheels provided on the trolley body, and a handle attached to the trolley body for controlling the traveling direction of the trolley body, a pusher applied to the handle is provided. It is characterized by comprising a detection means for detecting the pressure and a drive control means for rotationally driving the drive means at a speed corresponding to the output of the detection means. According to a second aspect of the present invention, a bogie body, first and second drive means for driving left and right driving wheels provided on the bogie body, and a traveling direction of the bogie body attached to the bogie body. In a hand truck having a handle for controlling the first handle, a first detector that detects a pressing force applied to the handle, a second detector that detects a rotational force applied to the handle, and the first detector. The first and second drive means are rotationally driven at a speed corresponding to the output of the first detection means, and the rotation speeds of the first and second drive means are respectively changed based on the output of the second detection means. And a drive control unit for controlling acceleration / deceleration.

[0007]

According to the first aspect of the present invention, the pressing force applied to the handle is detected by the detecting means, and the driving means is rotated at a speed corresponding to the pressing force of the detecting means to drive the drive wheels. Then, the hand cart is driven. This allows
The hand cart can be run according to the walking speed of the operator. According to the second aspect of the present invention, the pressing force applied to the handle is detected by the first detecting means, and the first and second
The driving force is applied to the steering wheel, and the rotational force applied to the steering wheel is detected by the second detection means and output to the driving means. Then, the first and second driving means are rotationally driven at a speed corresponding to the output of the first detecting means. Further, based on the output of the second detecting means, a steering operation is performed in which the rotational speeds of the first and second driving means are accelerated and decelerated. As a result, the hand truck can be driven according to the walking speed of the operator, and the direction of the hand truck can be easily changed.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 is a perspective view showing a structure of a hand truck according to a first embodiment of the present invention and a partially cut front view thereof. 2A is a sectional view taken along line XX in FIG.
(B) is a top view of FIG. The same parts as those described in FIG. 7 are designated by the same reference numerals and the description thereof will be omitted. 1 and 2, the motor power supply and the control device are not shown in order to avoid complication. In the hand truck of the first embodiment shown in these figures, the tacho generator 14 and the pressure sensor 10 are provided.
0 and the pressure detection unit 6 including the springs 200a and 200b are newly provided. The tacho generator 14 detects the rotation speed of the motor 3. Pressure detector 6
Detects the force applied by the operator in the traveling direction D to the handles 7a and 7b.

FIG. 3 is a block diagram showing the electrical construction of the first embodiment described above. In this figure, reference numeral 100 is the pressure sensor shown in FIG. 2, and its output signal ep is supplied to the adder 29. The adder 29 adds the constant voltage er and the signal ep, and outputs the result to the subtractor 30. The subtractor 30 subtracts the output ef of the signal processing unit 32 from the output of the adder 29, and outputs the result to the amplifier 31. The amplifier 31 amplifies the output of the subtractor 30 and outputs it to the motor 3. The motor 3 is driven by the output of the amplifier 31, and the drive wheel 1 (FIG. 2) is driven by the motor 3. Sign 1
Reference numeral 4 is a tacho generator that detects the rotation speed of the motor 3, and outputs a signal proportional to the rotation speed of the motor 3 to the signal processing unit 32. The signal processing unit 32 is the tacho generator 1
The output of No. 4 is waveform-shaped and output to the subtractor 30 as the signal ef. The drive wheel 1, the motor 3, the tacho generator 14, the subtractor 30, the amplifier 31, and the signal processing unit 3 described above.
The traveling control unit C is composed of 2. In such a configuration, when the circuit is powered on, the constant voltage er is supplied to the amplifier 31 via the adder 29 and the subtractor 30. At this time, the output of the pressure sensor 100 is at 0 level. The amplifier 31 amplifies the output of the subtractor 30 and supplies it to the motor 3. As a result, the motor 3 starts rotating, the drive wheels 1 are driven, and the carriage body 9 starts moving. When the motor 3 starts rotating, the tacho generator 1
4 outputs a voltage proportional to the rotation speed of the motor 3,
As a result, the signal processing unit 32 outputs the voltage ef proportional to the rotation speed of the motor 3 and supplies the voltage ef to the subtractor 30. The subtractor 30 subtracts the voltage ef from the voltage er and outputs the subtraction result to the amplifier 31. The amplifier 31 amplifies the output of the subtractor 30 and supplies it to the motor 3. Due to the above feedback control, the rotation speed of the motor 3 becomes equal to the voltage er.
The speed corresponds to (for example, 3 km / h). Next, if the operator wants to slightly increase the speed of the dolly, the handle 7
A force in the traveling direction D is applied to a and 7b. When the operator applies a force to the handles 7a and 7b, a compression force is applied to the pressure sensor 100, and a voltage ep corresponding to this compression force is output from the pressure sensor 100. As a result, the adder 2
A voltage (er + ep) is output from 9, and as a result, the speed of the motor 3 is accelerated to a speed corresponding to the voltage (er + ep). When the operator loosens the force applied to the handles 7a and 7b, the voltage ep decreases, so that the output voltage of the adder 29 also decreases and the rotation speed of the motor 3 decreases. As described above, according to the first embodiment, it is possible to drive the carriage according to the walking speed of the operator.

<Second Embodiment> A second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a perspective view showing a structure of a hand truck according to a second embodiment of the present invention and a partially cut front view. 5 is a cross-sectional view taken along line YY of FIG. 4 and a top view of FIG. In these figures,
The parts corresponding to those in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted. In these drawings, reference numeral 55 is a handle provided with grips 54a and 54b on the left and right. Reference numeral 53 is a twist detection unit that detects twist (rotation angle and rotation direction) of the handle 55 and converts the twist into an electric signal. Reference numeral 57 is a pressure detection unit, and as shown in FIG. 5A, it is composed of rubbers 51a and 51b and a pressure sensor 100 inside. This pressure sensor 1
00 detects the force applied to the handle 55 in the traveling direction D as an electric signal. Reference numeral 52 is an elastic body. Sign 1
Drive wheels a and 1b are driven by a motor (not shown). Reference numerals 50a and 50b are driven wheels (see FIG. 5B).

FIG. 6 is a block diagram showing the electrical construction of the second embodiment described above. In this figure, parts corresponding to those in FIG. 3 are assigned the same reference numerals and explanations thereof are omitted. Further, since the traveling control units A and B in FIG. 6 have the same configuration as the traveling control unit C in FIG. 3, their description will be omitted.
In this figure, the rotation angle and the rotation direction of the handle 55 are detected, and the voltage en is applied to the adder 33a and the subtractor 33b.
A twist detector 53 for outputting is newly provided.

In such a structure, when the circuit is powered on, the constant voltage er is added to the adder 29 and the adder 33a.
And to the subtracters 30a and 30b via the subtractor 33b. At this time, the outputs of the pressure sensor 100 and the twist detector 53 are at 0 level. After that, the traveling control units A and B perform the same operation as the traveling control unit C in FIG. 3, so that the hand truck starts traveling at a constant speed. Next, when the operator wants to slightly increase the speed of the dolly, a force in the traveling direction D is applied to the handle 55. When the operator applies a force to the handle 55, a compression force is applied to the pressure sensor 100, and a voltage ep corresponding to this compression force is output from the pressure sensor. As a result, the voltage (e
It is accelerated to a speed corresponding to r + ep). When the operator loosens the force applied to the handle 55, the voltage ep decreases, so that the output voltage of the adder 29 also decreases and the rotation speeds of the motors 3a and 3b also decrease. Next, when the operator wants to change the traveling direction of the carriage, the handle 55 is rotated in the desired direction. For example, handle 55 to the right
When is rotated, the twist detector 53 is twisted in the right direction, and a voltage (+ en) corresponding to this twist (rotation direction, rotation angle) is output from the twist detector 53. As a result, the voltage (er + ep + en) is output from the adder 33a, while the voltage (er + ep-e) is output from the subtractor 33b.
n) is output. As a result, the speed of the motor 3a is accelerated to the speed corresponding to the voltage (er + ep + en), while the speed of the motor 3b is decelerated to the speed corresponding to the voltage (er + ep-en), and the carriage is turned to the right. It When the operator returns the handle 55, the voltage en becomes 0 level and the vehicle travels straight. When the operator wants to change the traveling direction of the cart to the left, the handle 55 is rotated to the left. A twist in the left direction occurs in the twist detector, and a voltage (-en) corresponding to this twist is output from the twist detector 53. As a result, the voltage (er + ep-en) is output from the adder 33a, while the subtractor 33a
The voltage (er + ep + en) is output from b. As a result, the speed of the motor 3a is reduced to the speed corresponding to the voltage (er + ep-en), while the speed is reduced. The speed of the motor 3b is accelerated to the speed corresponding to the voltage (er + ep + en), and the carriage is turned to the left.

As described above, according to the second embodiment,
Similar to the first embodiment, the traveling speed of the hand cart can be adjusted to the walking speed of the operator, and the traveling direction can be freely changed. Since the two driving wheels are provided, the driving force is increased and the loading amount can be increased. Further, since the drive wheels 1a, 1b and the handle 55 are not mechanically connected to each other, the rotating operation of the handle 55 does not require much force, and thus even a woman can perform the operation easily.

The first and second embodiments of the present invention have been described in detail above with reference to the drawings. However, the specific structure is not limited to these embodiments. For example, a motor as a drive source may be used. Although an example in which the engine may be used as a drive source and an example of a hand cart to be operated by an operator has been shown, the present invention is also applicable to manual operation of an automated guided vehicle.

[0015]

As described above, according to the first aspect of the present invention, the traveling speed of the hand cart can be adjusted to the walking speed of the operator. According to the second aspect of the present invention, the traveling speed of the hand cart can be adjusted to the walking speed of the operator, and the hand cart can be easily turned in any direction.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a hand cart according to a first embodiment of the present invention and a partially cut front view.

FIG. 2 is a cross-sectional view taken along line XX of FIG. 1A and a top view showing the configuration of the hand truck according to the embodiment.

FIG. 3 is a block diagram showing a control unit of the hand cart according to the embodiment.

FIG. 4 is a perspective view showing a structure of a hand cart according to a second embodiment of the present invention and a partially cut front view.

5 is a cross-sectional view taken along the line YY of FIG. 4A and a top view showing the configuration of the hand truck according to the embodiment.

FIG. 6 is a block diagram showing a control unit of the hand cart according to the embodiment.

FIG. 7 is a perspective view and a partially cut front view showing a configuration of a conventional hand truck.

FIG. 8 is an enlarged front view showing an operating portion of a conventional hand truck.

[Explanation of symbols]

 7a, 7b handle 1 drive wheel 3 motor 6 pressure detector 14 tacho generator

Claims (2)

[Claims] 1. A hand-pushed trolley having a trolley body, drive means for driving drive wheels provided on the trolley body, and a handle attached to the trolley body for controlling the traveling direction of the trolley body, wherein the handle is provided. A hand truck comprising: a detection unit that detects the pressing force applied to the drive unit; and a drive control unit that rotationally drives the drive unit at a speed corresponding to the output of the detection unit. 2. A trolley body, first and second drive means for driving left and right drive wheels provided on the trolley body, and a handle attached to the trolley body for controlling a traveling direction of the trolley body. In a hand cart having a first detection means for detecting a pressing force applied to the handle, a second detection means for detecting a rotational force applied to the handle, and an output of the first detection means. At the speed corresponding to the first,
Drive control means for rotationally driving the second drive means, and controlling acceleration and deceleration of the rotation speeds of the first and second drive means based on the output of the second detection means. Wheelbarrow.