JPH0419477Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention relates to a level detection device for determining the remaining amount of powder or granular material.

<Problems with conventional technology> A weight is lowered into a tank containing powder or granules such as cement, and the level of the powder or granules is detected by the amount of movement of the weight from the reference position to the position where it hits the top surface of the powder or granules. Devices designed to do this are well known and are equipped with a mechanism for detecting that the weight has landed. An example of such a mechanism is one in which a float is built into the weight, and a switch inside the weight is opened and closed by the movement of the float upon landing (for example,
(Refer to Publication No. 14907), this structure requires a cable to be connected between the weight and the main body, which causes problems such as the structure of the weight becoming complicated. As for other structures, for example, a spring applies lateral pressing force to the hanging wire of the weight, and detects that the wire slackens and moves laterally when the weight lands. However, there is a problem that the response speed is slow.

Furthermore, a worm is used as a reducer between the drive motor and the rotating drum for suspending the weight, and the worm is moved in its axial direction by the change in the balance of rotational moment when the weight lands. A device that detects movement is also known (see, for example, Japanese Utility Model Publication No. 10539/1983). However, this publication tends to have a large and complicated structure because the axes are perpendicular to each other in the worm part, and since the rotating drum is decelerated and driven by the worm, the sensitivity for detecting balance changes tends to be low. ,
It is thought that there is still a problem of poor responsiveness.

This invention was developed in view of these problems and with the aim of providing a detection device with a simple structure and fast response speed.

<Means for solving the problem> In order to achieve the above-mentioned purpose, in this invention,
A rotating member that is coaxially inserted into the drum shaft of the hoisting drum and rotated by a drive motor, a guide pin provided on the drum shaft, and an oblong hole provided at an angle in the rotating member are combined, and the rotating member is inserted into the drum shaft. An engaging part configured to move forward along the drum shaft when rotated in a descending direction with respect to the shaft and to move backward when rotated in a winding direction, and an engaging part constructed between the drum shaft and the rotating member to rotate the drum shaft. A first biasing spring biases the member in the winding direction and transmits the rotation of the drive motor to the drum shaft, and a second biasing spring biases the rotating member in the forward direction. By appropriately selecting a combination of the biasing force of each of the biasing springs, the shape and frictional force of the engaging portion, and the weight of the weight, when the rotating member is rotated in the downward direction by the drive motor, the drum shaft Therefore, the hoisting drum rotates in the downward direction and stops when the weight hits the top surface of the powder, and furthermore, only the rotating member rotates and moves forward, and the movement of this rotating member is detected by a limit switch. I try to do that.

<Function> When the weight is not in contact with the top surface of the powder, a rotational moment in the descending direction due to the weight of the weight is applied to the drum shaft, and this is combined with a rotational moment in the winding direction due to the first biasing spring. Balanced. Therefore, when the rotating member is driven by the drive motor and rotates in the descending direction, the drum shaft also rotates in the descending direction and the weight descends. When the weight hits the upper surface of the powder, the rotational moment in the downward direction due to the weight disappears, so the drum shaft stops, and only the rotating member rotates due to the urging force of the first urging spring. Therefore, the rotary member moves forward due to the synergistic effect of the inclined elongated hole of the engaging portion and the biasing force of the second biasing spring.
By detecting the movement of this rotating member with a limit switch, it is detected that the weight has reached the upper surface of the powder material.

<Example> Next, one embodiment shown in the drawings will be described.

In Figure 1, 1 is a hoisting drum, 2 is a stainless steel measuring tape wrapped around the hoisting drum 1, 3 is a weight attached to the tip of the measuring tape 2, and 4 is a hoisting drum 1 fixed. The drum shaft 4 is supported by a bearing of the device main body (not shown). 1a is a fixing screw. 5
is a rotating member that is fitted onto the drum shaft 4 and includes a cylindrical boss portion 51, a large-diameter gear 52, and a flange 53;
Reference numeral 6 indicates a drive motor provided in the main body of the apparatus, and reference numeral 7 indicates a small gear fixed to the output shaft of the drive motor 6 and meshing with the gear 52.

Reference numeral 8 designates an engaging portion, which includes a guide pin 81 provided through the drum shaft 4 in the radial direction, and a boss portion 5 of the rotating member 5 such that the guide pin 81 is inserted therein.
1 with a long hole 82 inclined at a predetermined helix angle.
The inclination of the elongated hole 82 is such that when the rotating member 5 rotates relative to the drum shaft 4 in the direction in which the weight descends, the inclination of the elongated hole 82 moves to the left in the figure (hereinafter, this direction is referred to as the forward direction). It is oriented so that it moves forward and, conversely, when the weight is rotated in the direction of hoisting it up, it moves back to the right in the figure. A push spring 9 is inserted between the adjustment ring 10 fixed to the drum shaft 4 and the flange 53 of the rotating member 5, and urges the rotating member 5 in the forward direction. 10a is a fixing screw.

11 is a spring cover fixed to the drum shaft 4;
2 is a spiral spring. The spiral spring 12 is installed between the spring cover 11 and the rotating member 5,
The spring cover 11 is connected to the rotating member 5.
A spiral spring 12 is fixed to the drum shaft 4 in a state where it is wound in a direction in which it is urged in the winding direction. 11a is a fixing screw.

13 is a rotation sensor, 14 is a sensor rotating body fixed to the drum shaft 4, 15 is a limit switch for detecting landing, 16 is a control device, 17 is an upper limit stopper, 18 is a stopper, and 19 is an upper limit switch. The rotation sensor 13 is, for example, an electromagnetic pickup, and a plurality of projections 14a made of a magnetic material are provided at equal intervals on the outer periphery of the sensor rotation body 14.
The amount of movement of the weight is detected from the number of revolutions of the drum shaft 4 obtained by counting the passage of the protrusion 14a. The limit switch 15 detects that the rotating member 5 has moved in the forward direction, and is arranged close to the rotating member 5. Further, the upper limit stopper 17 is provided so as to sandwich the measuring tape 2 in correspondence with a stopper 18 attached to the lower end of the measuring tape 2, and has a structure that also serves as an actuator for the upper limit switch 19. .

Please note that the figure shows the basic configuration.
For example, an auxiliary support plate supported via a ball bearing may be provided on the surfaces of the adjustment ring 19 and flange 53 that the push spring 9 contacts, so that the rotating member 5 can move easily, so that each member can operate without any trouble. appropriate mechanisms will be adopted.

Next, the operation will be explained. 2A shows a state in which the weight 3 does not touch the upper surface of the powder or granule material, and b in the same figure shows a state in which the weight 3 touches the upper surface of the powder or granule material 20. Further, FIG. 3 shows the operating position of the rotating member 5, where the solid line indicates the position in the standby state where the weight 3 is at the upper limit position, and the chain line indicates the position in the standby state where the weight 3 is at the upper limit position.
The respective positions are shown in the landing state.

In the case of a in Fig. 2, the drum shaft 4 receives a rotational torque corresponding to the weight of the weight 3 via the hoisting drum 1.
F ₁ is added clockwise, and the spiral spring 12
The rotational torque F ₂ due to is applied in the counterclockwise direction, and the two are almost balanced. When the rotating member 5 is driven in the downward direction by the drive motor 6, the rotation is transmitted to the drum shaft 4 via the engaging portion 8, the hoisting drum 1 rotates, and the weight 3 descends. The slope of the elongated hole 82 and the guide pin 81 and the elongated hole 82
The frictional force between the rotary member 5 and the biasing force of the push spring 9 are appropriately selected so that the rotary member 5 remains in the retracted position shown in solid line in FIG. 3 during this descent.

When the weight 3 hits the top surface of the powder or granular material 20, the weight 3
Since the rotational torque F ₁ suddenly becomes zero, the above-mentioned balance is lost, and the drum shaft 4
The rotating member 5 stops at that position due to the biasing force caused by the rotating member 5, and only the rotating member 5 rotates further as shown in FIG. 2B. Therefore, due to the action of the engaging portion 8, the rotating member 5 moves forward to the position indicated by the chain line in FIG. 3, and the actuator of the limit switch 15 is pushed. This operation is performed by rotating member 5
and the drum shaft 4 are directly connected by the spiral spring 12 without the use of a speed reducer.
The drive motor 6 is stopped in response to the operation of the rotation sensor 13, and the descending distance of the weight 3 is calculated from the count number of the rotation sensor 13, and the result is displayed on a display on the main body of the apparatus (not shown). At this time, as mentioned above, the rotation of the drum shaft 4 stops immediately after the weight 3 lands, so the detection tape 2 may become slack and a detection error may occur, or the weight 3 may fall and become buried in the powder 20. This does not make winding difficult.

Next, the control device 16 reverses the drive motor 6, for example, one second after the drive motor 6 is stopped. As a result, the rotating member 5 reverses, the drum shaft 4 and the hoisting drum 1 rotate in the hoisting direction, and the weight 3 rises to the position where the stopper 18 hits the upper limit stopper 17. Therefore, the drum shaft 4 stops, and only the rotating member 5 rotates further and retreats to the position shown by the solid line in FIG. 3 against the urging force of the push spring 9. At the same time, the control device
6 stops the drive motor 6 in response to the operation of the upper limit stopper 17 and returns to the standby state. Note that the drive motor 6 is rotated so that the drum shaft 4 does not rotate naturally while the drive motor 6 is stopped due to the weight of the weight 3.
A brake motor is used.

Here, the forward and backward movement of the rotating member 5 when the weight 3 hits the upper surface of the powder or granular material 20 and when the stopper 18 hits the upper limit stopper 17 is determined by the engagement portion 8
By keeping the inclination (torsion angle) of the elongated hole 82 appropriately small, high speed operation can be achieved. This is effective in speeding up detection and response speed.

<Effects of the invention> As is clear from the above-mentioned embodiments, this invention has a rotating member that moves forward or backward depending on the direction of rotation coaxially inserted into the drum shaft to which the hoisting drum is fixed, and the weight is When it hits the top surface of the granules, the balance between the biasing force by the first biasing spring provided between the drum shaft and the rotating member and the rotational moment is disrupted, causing the guide pin and the inclined elongated hole to The rotating member is moved forward by the action of the engaging portion, and the upper surface level of the powder is detected by detecting the movement.

Therefore, the structure of the weight does not become complicated,
Since no worm gear is used, the entire system can be made compact, and the landing of the weight can be detected quickly and reliably, making it possible to easily create a powder level detection device with fast response speed and high detection accuracy. This mechanism can be obtained at low cost.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the basic structure of an embodiment of this invention, FIG. 2 is an explanatory diagram of the operation, and FIG. 3 is an explanatory diagram showing the position of the rotating member during operation. 1... Winding drum, 2... Measuring tape, 3...
... Weight, 4 ... Drum shaft, 5 ... Rotating member, 6 ...
... Drive motor, 7 ... Small gear, 8 ... Engagement part, 9
... Pressing spring (second urging spring), 11 ... Spring cover, 12 ... Spiral spring (first urging spring),
13...Rotation sensor, 14...Rotating body for sensor,
15... Limit switch, 16... Control device,
20... Powder, 52... Gear, 81... Guide pin, 82... Long hole.

Claims (1)

[Scope of Claim for Utility Model Registration] A device in which a weight is lowered by a hoisting drum and the level of the powder or granule is detected by the amount of movement of the weight from a reference position to a position where it hits the top surface of the powder or granule. A rotating member that is coaxially inserted into the drum shaft to which the drum is fixed and is rotationally driven by a drive motor, and a rotating member that is installed between the drum shaft and the rotating member to move the drum shaft in the winding direction with respect to the rotating member. A first biasing spring that biases and transmits the rotation of the drive motor to the drum shaft, a guide pin provided on the drum shaft, and an oblong hole provided at an angle in the rotating member are combined to cause the rotating member to rotate toward the drum shaft. an engaging portion configured to move the rotating member forward along the drum axis when rotated in the downward direction relative to the drum, and to move the rotating member backward when rotated in the winding direction; and a second biasing member that urges the rotating member in the forward direction. It is equipped with a spring and a limit switch that detects the forward movement of the rotating member, and a drive motor rotates the rotating member in the descending direction, and when the hoisting drum rotates in the descending direction and the weight hits the top surface of the powder, the hoisting drum stops. In addition, the biasing force of each of the biasing springs, the inclination of the elongated hole of the engaging part, and the weight are adjusted so that only the rotating member rotates and the rotating member advances due to the action of the engaging part, thereby operating the limit switch. A level detection device for powder and granular materials by selecting the weight of