JPH0139526B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that generates a stepwise signal representing the positional relationship between two relatively moving objects.

Such a device is useful for controlling the relative positioning of two objects or for controlling other physical quantities based on the relative positional relationship of two objects. For example, when you want to stop a moving object accurately at a predetermined position, the moving object is decelerated when it approaches the predetermined position to a certain extent, and as it approaches the predetermined position, the speed is further reduced to stop the moving object at a predetermined position. Step-by-step control such as stopping when a position is reached becomes possible.

However, the conventional stepwise position signal generator requires a number of position detectors equal to the number of steps. For example, in order to control the speed of the movable body in two stages and to stop it, it is necessary to detect three positions of the movable body, so at least three position detectors are required.

This invention is capable of detecting more positions than the number of reed switches with a small number of reed switches, that is, with two reed switches, three positions can be detected.
The present invention provides a device capable of generating a step-by-step position signal.

Hereinafter, some embodiments of the present invention will be described in detail with reference to the drawings.

In FIGS. 1 and 2, it is assumed that the movable body 2 moves relative to the fixed body 1 in the direction of the arrow.
There are two reed switches A and B on the fixed body 1.
Magnets 3 are respectively fixed to the movable body 2 on opposing surfaces thereof. Reed switch A is
The reed switch B is arranged so that its longitudinal direction coincides with the moving direction of the movable body 2, and the reed switch B is placed on a straight line passing through the center of the reed switch A and perpendicular to the moving direction of the movable body 2. It is provided perpendicular to reed switch A and a little apart from reed switch A. Reed switch A, B
As is clear from FIG. 1, the longitudinal direction of the two magnetic leads 4 corresponds to the longitudinal direction of the two magnetic leads 4. The magnet 3 may be either a permanent magnet or an electromagnet. The size and position of the magnet 3 are determined so that when the movable body 2 moves, the locus of the magnet 3 covers almost all of the reed switch A and a part of the reed switch B.

When the magnet 3 moves on both reed switches A and B as the movable body 2 moves, the reed switches A and B operate, and their magnetic leads 4
touch or separate. FIG. 3 shows the operation of reed switches A and B by the magnet 3.
When magnet 3 approaches reed switch A, reed switch A is turned on. Magnet 3 leads
Reed switch A is held on while scanning over switch A, but when magnet 3 reaches the exact center position of reed switch A, reed switch A is temporarily turned off. Become.
When magnet 3 leaves reed switch A, reed switch A is turned off. Further, when the magnet 3 is scanning over the reed switch B, the reed switch B is turned on. The length of time (or distance) that reed switch B is on
is smaller than the time period during which reed switch A is on, and greater than the time period during which reed switch A is temporarily off. There is hysteresis in the operation of reed switches A and B, and the operation of both reed switches A and B when magnet 3 moves in opposite directions is shown in broken lines.

FIG. 4 shows a relay circuit that uses signals from reed switches A and B to turn on red, yellow, and green indicator lights 13, 14, and 15 depending on the position of the movable body 2. FIG. 5 shows the blinking states of each of the indicator lights 13 to 15. Each reed switch A,
B relay 11,1 when it turns on
Operate 2. The relay 11 includes a normally open contact 11a and a normally closed contact 11b, and the relay 12 includes normally open contacts 12a1, 12a2 and a normally closed contact 12b.

When the reed switch A is turned on as a result of the magnet 3 approaching the reed switch A, the relay 11 is energized and the contact 11a is turned on. Since reed switch B is still off, contact 12b remains on, and red indicator light 13 lights up.

When the magnet 3 approaches the reed switch B, the reed switch B is turned on and the relay 12 is energized. Reed switch A remains on. Therefore, contact 12b is turned off, so
The red indicator light 13 goes out and the contact 12a1 turns on, so the yellow indicator light 14 lights up.

When magnet 3 reaches the exact center of reed switch A, reed switch A is temporarily turned off.
Reed switch B remains on. Therefore, since the contact 11a is turned off, the contact 11b is turned on, and the contact 12a2 is turned on, the red and yellow indicator lights 13 and 14 are turned off, and the green indicator lamp 15 is turned on.

When magnet 3 moves away from reed switches A and B, the order is reversed, i.e. green, yellow,
It is easy to understand that the lights turn on in red order.

Such a stepwise lighting display of the three types of indicator lights 13 to 15 is useful, for example, when moving the movable body 2 manually and positioning it to stop at a predetermined position. Red, yellow, and green indicator lights each have meanings such as approach, caution, and stop.

As an example, it could be used to determine the height position of a fork on a work vehicle. The reed switches A and B are attached to the mast, and the magnet 3 is attached to the elevating member of the fork. Indicator lights 13 to 15 are then placed at the driver's seat. The driver reduces the speed of the fork when the red indicator light 13 lights up, then carefully operates the fork up and down when the yellow indicator light 14 lights up, and then starts the fork when the green indicator light 15 lights up. make it stop. Since the lighting range of the green indicator light 15, that is, the range in which the reed switch A is turned off at any one time, is very narrow, accurate positioning of the fork is possible.

Instead of or in addition to lighting the indicator lights 13 to 15, these lighting control signals may be used to perform other controls, such as generating an alarm, or to automate the above-mentioned manual operation of the forks.
In automatic speed and stop control of the movable body 2,
The lighting signal of the red indicator lamp 13 is used as a first deceleration signal, the lighting signal of the yellow indicator lamp 14 is used as a second deceleration signal, and the lighting signal of the green indicator lamp 15 is used as a stop signal.

The lighting control of the indicator lights 13 to 15 as described above is as follows:
This can be realized not only by using a relay circuit but also by using a logic circuit as shown in FIG. The red indicator light 13 is activated by the AND signal (circuit 23) of the ON signal of reed switch A and the NOT signal of reed switch B, and the yellow indicator lamp 14 is activated by the ON signal of reed switches A and B. AND signal (circuit 24)
Accordingly, the green indicator lamp 15 is turned on by the AND signal (circuit 25) of the NOT signal of the reed switch A and the ON signal of the reed switch B.

In the case of the circuits shown in FIGS. 4 and 6, the three signal lines connected to the red indicator light 13, yellow indicator light 14, and green indicator light 15, respectively, are the first position signal, the second position signal, and Each corresponds to the third position signal. When reed switch A is on and reed switch B is off,
The output of the signal line of the red indicator light 13 is turned on,
A first position signal is output, and reed switch A,
When both B are on, yellow indicator light 1
When the output of the signal line 4 is turned on and the second position signal is output, and the reed switch A is off and the reed switch B is on, the output of the signal line of the green indicator 15 is turned on. It is turned on and the third position signal is output.

Figure 7 shows the 3
8 shows a relay circuit for controlling the opening and closing of various types of solenoid valves 33 to 35, and FIG.
5 is shown. In FIG. 7, the same components as those shown in FIG. 4 are given the same reference numerals. When either reed switch A or B is on, either contact 11a or 12a1 is on, so solenoid valve 33 is closed during this period. If reed switch B is on regardless of the state of reed switch A, contact 12a2
is on, so the solenoid valve closes when reed switch B is on. When reed switch A is temporarily turned off, contact 11b is turned on, reed switch B is kept on, and contact 12a2 is turned on, so during this period, solenoid valve 35 is closed. . In this way, the solenoid valves 33 to 35 can be controlled in stages as the movable body 2 moves.

In the case of the circuit shown in Fig. 7, the solenoid valves 33, 34, 35
A first position signal, a second position signal, and a third position signal are output by a combination of the outputs of three signal lines respectively connected to the first position signal, the second position signal, and the third position signal. In other words, the lead
When switch A is on and reed switch B is off, the output of the signal line of solenoid valve 33 is on, the output of the signal line of solenoid valves 34 and 35 is turned off, and the first position signal is output. When reed switches A and B are both on, the output of the signal lines of solenoid valves 33 and 34 is on, the output of the signal line of solenoid valve 35 is off, and the second position signal is output. When the reed switch A is off and the reed switch B is on, the solenoid valves 33, 3
The outputs of signal lines 4 and 35 are all turned on, and the third position signal is output.

In addition to the two reed switches constituting the position signal generator of the present invention, a third reed switch is provided, for example, in parallel with reed switch B and outside the detection range of reed switch A. , four-stage control is possible. Furthermore, more stepped signals can be obtained by increasing the number of reed switches.

The stepwise position signal generating device according to the present invention includes:
a first reed switch provided on one of two objects moving relatively and disposed in a direction in the direction of relative movement of the two objects; a first reed switch provided on the same object; - A second line located on a line passing through the center of the switch and perpendicular to the direction of movement.
a reed switch, a magnet disposed on the other object, facing both reed switches and actuating both reed switches, and a magnet for activating both reed switches while the first reed switch is on and the second reed switch is off. a first position signal representing a condition in which the first reed switch is on and a second reed switch on; and a second position signal indicative of a condition in which the first reed switch is off and the second reed switch is on. Since the position signal generation means outputs a third position signal representing the state, two reed switches are used, one in which the magnet approaches the center of the first reed switch, and the other in which the magnet approaches the center of the first reed switch. A stepped signal can be generated in three positions: a second position closer to the center of the first reed switch, and a third position where the magnet is exactly in the middle of the first reed switch.

[Brief explanation of drawings]

Figures 1 and 2 show the arrangement of reed switches and magnets, with Figure 1 being a sectional view and Figure 2 being a cross-sectional view.
The figure is a plan view, Figure 3 is a chart showing the operation of the reed switch, Figures 4 and 5 show the case where the indicator light is lit by the signal from the reed switch, and Figure 4 is a relay circuit diagram. , Fig. 5 is a chart showing the operation of the indicator light, Fig. 6 is a circuit diagram when the circuit of Fig. 4 is configured by a logic circuit, and Figs. 7 and 8 are diagrams showing the operation of the indicator light. 7 is a relay circuit diagram, and FIG. 8 is a chart showing the operation of the solenoid valve. 1...Fixed body, 2...Movable body, 3...Magnet, A, B...
Lead switch.

Claims (1)

[Claims] 1. A first reed switch provided on one of two relatively moving objects and disposed in the direction of relative movement of both objects; a second reed switch provided on the other object and located on a line passing through the center of the first reed switch and perpendicular to the direction of movement; and a first position signal representing a state in which the first reed switch is on and the second reed switch is off; position signal generating means for outputting a second position signal indicative of a state and a third position signal indicative of a state in which the first reed switch is off and the second reed switch is on. Generator.