JPH10289639A - Gradient switch device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have a simple structure strong in vibration and surely operate as a gradient switch by providing a sphere having a prescribed weight, a sphere receiver having a gradient surface for mounting the sphere on its inside, and a sphere self-reset switch which is positioned in the bottom end part of the gradient surface and in a conductive state while being press by the sphere. SOLUTION: In a steel sphere receiver 9 which has a truly spherical steel sphere 7 having a prescribed weight, for example, the diameter 50 mm and the weight approximately 540 g mounted thereon and a conical gradient surface 8 on its inside, the inner gradient surface 8 is formed into an inverse conical shape with the downward angle θ of 30 deg. to the horizontal plane. Therefore, when a plane body is inclined and the steel sphere 7 mounted on the gradient surface 8 is inclined 30 deg. or more, an approximately 80 g reset force of a pushbutton 12a of a sphere self-reset switch 12 can push the steel sphere 7 in the horizontal direction so as to rotate it on the gradient surface 8 which is turned into a horizontal surface, release the pushing force of the pushing button 12a, and stop the motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilt switch device which maintains an energized state when a tilt of a main body is less than a predetermined angle, and is particularly suitable for an electric lawn mower using a DC motor.

[0002]

2. Description of the Related Art In general, there are many types of tilt switches that open and close switches by tilting and are used for various purposes. Tilt switches are used to prevent damage or breakage of the equipment. But,
The tilt switch conventionally used for a specific specific working machine such as an electric lawn mower using a DC motor is not always optimal for the component configuration of the working machine or a unique work. Yes, the allowable inclination differs depending on the type of work and the place where the work machine is used, and the unexpected inclination due to the allowable inclination of opening and closing the switch, whether the switch always operates at a constant inclination, and vibration etc. Careful consideration must be given to whether the switch is opened and closed in the future. In particular, when a rotary cutter is used in a work machine, such as the electric lawn mower, even if the power is stopped by the tilt switch before the body falls, the rotary cutter continues to rotate due to its inertia. It is necessary to avoid breakage of the rotary cutter, danger to the human body, and the like, and attention and contrivance are required in various fields, and the function of the tilt switch is very important.

There are various types of electric lawn mowers as one of the working machines that use the tilt switch that requires such a multifaceted function, and an AC or DC motor is used as a power source. The configuration differs depending on whether the mower itself has a power cord or a battery. When the electric lawn mower is rolled over and the cutting blade is replaced, a safety measure is desired in which the motor can be energized and the motor does not rotate even if the switch is turned on accidentally, as described above. A tilt switch device having a function of preventing the electric lawn mower from overturning and the cutting blade from continuing to rotate by inertia is desired, but at present, such a tilt switch device has not yet appeared. is there.

[0004]

SUMMARY OF THE INVENTION In order to provide a tilt switch device having various functions as described above, the present invention uses a self-returning switch and a sphere for operating the switch by its own weight. It is an object of the present invention to provide a tilt switch device that has a simple structure that is strong against vibration and that reliably functions as a tilt switch.

[0005]

That is, a tilt switch device according to the present invention comprises a sphere having a predetermined weight, a sphere receiver having an inclined surface on the inside on which the sphere is mounted, and a lower end of the inclined surface. And a self-restoring switch for a sphere that is in an energized state while being pressed by the sphere. And as a preferred embodiment of the tilt switch device according to the present invention, the spherical self-return switch,
In the closed circuit between the DC motor and the battery, there is one in which the DC motor is connected in series with another self-returning switch, and the DC motor can be quickly stopped regardless of which switch is opened. Furthermore, the battery, the DC motor, the tilt switch, etc. used for the electric lawn mower can be arranged without waste, and the three switches of the motor starting switch, the tilt switch, and the power switch are connected in series to provide more safety. It enables a great lawn mowing effect.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 show an electric lawn mower M having a cutting width of about 25 cm using a tilt switch device 1 according to an embodiment of the present invention. This electric lawn mower M is
A push handle 2 extending upward and rearward from the cutting blade cover 22 is provided. A battery 4 is disposed on the rear side of the upper portion of the cutting blade cover 22 as shown in FIG. 5, the tilt switch device 1 is juxtaposed on the other side so that no useless space is provided. A deceleration output shaft 5b of a speed reducer 5a directly connected to the DC motor 5 is protruded into the cutting blade cover 22, and a rotary cutting blade 3 is rotatably attached to a lower end thereof in a cutting plane. As shown in FIG. 3, the tilt switch device 1 has a spherical steel ball 7 having a predetermined weight, in this embodiment, a diameter of 50 mm and a weight of about 540 grams,
The downward angle θ with respect to the horizontal plane on the inside where the steel ball is placed
However, for example, a steel ball receiver 9 having a 30-degree bevel-shaped inclined surface 8, a cover 11 forming a closed storage chamber 10 for the steel ball 7 with the steel ball receiver 9, The push button 12a is at a lower end and is in an energized state while being pressed by the steel ball 7, with a force of about 400 grams.
And a self-recovering single-pole double-throw microswitch 12 for a sphere having a rated power of about 21 amps.

In the tilt switch device 1, the inner inclined surface 8 formed in the steel ball receiver 9 is formed in an inverted conical shape with a downward angle .theta. Of 30 degrees with respect to the horizontal plane. When the body is tilted and the steel ball 7 placed on the inclined surface 8 is tilted by 30 degrees or more as shown in FIG. 4, about 80 grams of the push button 12a of the ball self-return type switch 12 With the restoring force, the steel ball 7 can be rolled on the horizontal inclined surface 8 by pressing the steel ball 7 in the horizontal direction, and the pressing of the push button 12a is released.
The tilt switch device 1 is opened, and the motor 5 is stopped. The reason why the weight of the steel ball 7 is set to be sufficiently large is to prevent useless opening and closing of the switch during lawn mowing work in consideration of vibration of the electric lawn mower and unevenness of the lawn mowing surface. If a vibration damping member that absorbs vibration is used when installing the tilt switch device 1,
Smaller, lighter spheres may be used.

As shown in FIG. 5, the electric circuit of the electric lawn mower M includes a sphere self-return type switch 12 and a motor start-up self-return type single in a closed circuit between the DC motor 5 and the battery 4. And a double-throw microswitch 13 connected in series and interposed therebetween, and the respective switches 12, 13
When the connection between the common terminal COM and the normally-open terminal NO is open, the short-circuit wire 14, which automatically closes the common terminal COM and the normally-closed terminal NC to form a closed circuit with the DC motor 5,
15 constitute a quick stop circuit. As shown in FIG. 1, the motor-starting self-returning switch 13 is a safety switch operated by gripping the hand push handle 2 by an operator, and when the worker's hand separates from the safety switch 13 in an emergency or the like. The power supply is automatically cut off and the circuit is short-circuited, so that the DC motor 5 stops quickly.
In the circuit of FIG. 5, the self-returning type switch 1 for starting the motor is further considered in consideration of the further safety of the electric lawn mower M.
3 and a power switch 16 as a third switch in addition to the self-returning switch 12 for a sphere, are attached to an appropriate position of the hand push handle 2.
2, 13 are connected in series. Therefore, if any of these three types of switches 12, 13, 16 are opened,
The cutting blade 3 of the electric lawn mower M cannot be rotated, which is extremely safe. In the drawing, reference numeral 20 denotes the cut grass cut by the cutting blade 3 and the cutting blade cover 2.
2 is a guide plate for guiding the grass collection bag 17 detachably attached to the rear side of the bag 2, and the heights 19, 19, 19, 19 are separately set on the right and left by appropriate height adjustment means 18, 18. And 21 is an auxiliary handle used when lifting the fuselage.

[0009]

As described above, the configuration of the present invention is a self-returning type switch for a sphere which is energized while a sphere having a predetermined weight is placed and pressed on a sphere receiver having an inclined surface inside. In combination, it is possible to obtain a tilt switch device with a simple and reliable structure that is resistant to vibration, and in particular, a safety surface for use in electric lawn mowers to prevent accidental accidents, and a self-resetting switch for spheres and a simple electric circuit. Thus, it is possible to provide a tilt switch device having various functions such as a configuration in which a quick stop circuit of a motor can be formed.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional schematic side view of an electric lawn mower using a tilt switch device according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view of a main part of the electric lawn mower shown in FIG. 1 with an upper cover removed.

FIG. 3 is a vertical sectional view of a main part of the tilt switch device according to one embodiment of the present invention.

FIG. 4 is an explanatory view of a state in which the tilt switch device shown in FIG. 3 is tilted.

FIG. 5 is a motor quick stop circuit diagram of an electric lawn mower using the tilt switch device according to one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Incline switch device 3 Cutting blade 4 Battery 5 DC motor 7 Steel ball 8 Inclined surface 9 Steel ball receiver 12 Self-return type switch for ball 13 Self-return type switch for motor start-up (safety switch) 14 Short-circuit line (quick stop circuit) 15 Short-circuit line (quick stop circuit) 16 Power switch (third switch) M Electric lawn mower

Claims (5)

[Claims] 1. A sphere (7) having a predetermined weight, a sphere receiver (9) having an inclined surface (8) inside on which the sphere (7) is mounted, and a lower end of the inclined surface (8) And a self-returnable switch for a sphere (12) that is in an energized state while being pressed by the sphere (7). 2. A battery comprising a DC motor (5) and a battery (4), wherein the DC motor (5) and the battery (4) are provided.
A self-return switch for motor start (1
3) and the self-returning switch for sphere (12) are connected in series and interposed, and the respective switches (12, 1) are connected.
3. The tilt switch device according to claim 1, wherein a quick stop circuit is provided in 3). 3. A safety switch in which the DC motor (5) is for driving a mowing blade (3) of an electric lawn mower (M), and wherein the self-returning type switch for starting the motor is operated by an operator. 3. The method according to claim 2, wherein
4. The tilt switch device according to claim 1. 4. The electric lawn mower (M) is provided with the battery (4) at the upper rear of the cutting blade (3), and the motor (5) is mounted on one of the left and right sides of the upper part of the cutting blade (3). The tilt switch device according to claim 3, wherein the tilt switches (1) are juxtaposed on the other side. 5. A power switch (16), which is a third switch, is connected in series in addition to the motor-starting self-returning switch (13) and the sphere self-returning switch (12). The tilt switch device according to claim 2, wherein