JP2608652B2 - Weighing device with shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weighing device having an impact buffering function for protecting a load detecting device when an impact is applied to a mounting table.

[0002]

2. Description of the Related Art When an object to be measured is thrown when the object to be measured is placed on a mounting table, the impact force acts directly on the load detecting device, and the load detecting device is damaged.

Therefore, as shown in FIG. 5, a load cell 4 serving as a load detecting device can be protected from an impact by interposing a damper 3 between the mounting table 1 and the fixed table 2. Also,
An auxiliary mounting table 6 is provided on the mounting table 1 via a cushion material 5 as shown by a virtual line in FIG. 4 without using such a damper 3, and the object to be measured is mounted on the auxiliary mounting table 6. To protect the load cell 4 from impact force.

[0004]

Although the damper 3 can be expected to have a larger damping capacity than the cushioning material 5, a part of the load is always supported by the damper 3. Therefore, there is a problem that the measurement accuracy is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a weighing device with an impact buffer which can expect a large buffering capacity and does not cause a decrease in measurement accuracy.

[0006]

According to the present invention, there is provided a weighing device with a shock absorbing device, wherein a compression spring is interposed between a supporting table on which the table is mounted and a fixed side, and the table is a load detecting device. And a cylinder device is interposed between the support table and the fixed side in parallel with the compression spring, and is compressed by a load from a mounting table of both cylinder chambers of the cylinder device. A first switching state in which both the first cylinder chamber and the second cylinder chamber on the opposite side of the first cylinder chamber communicate with the tank for the working fluid, and a first switching state in which the first cylinder chamber communicates with the tank, Actuates between a second switching state in which the second cylinder chamber is connected to the discharge port and a third switching state in which the second cylinder chamber is connected to the tank and the first cylinder chamber is connected to the discharge port of the pump. A switching valve for switching a fluid flow path is provided, and a first valve is provided. A throttle valve is provided in a discharge path of the working fluid from the cylinder chamber or a suction path of the working fluid into the second cylinder chamber, and is arranged in parallel with the throttle valve in a direction that does not hinder the suction of the working fluid into the first cylinder chamber. Providing a connected check valve,
During standby, the switching valve is set to the first switching state, and when a state in which the load detected by the load detection device exceeds the specified weight is detected, the switching valve is set to the second switching state, and then the switching valve is set to the second switching state. A control unit for switching to the switching state of No. 3 is provided.

[0007]

According to this structure, the support stand is pushed up by the compression spring and the mounting stand is separated from the load detecting device until the control section detects the state during the measurement.

When the object to be measured is mounted on the mounting table, a compressive force acts on the first cylinder chamber of the cylinder device via the support table, and the first cylinder chamber is supplied at a flow rate per unit time determined by the throttle valve. Is pushed out, the support gently descends toward the load detector, and the load is applied to the load detector.

[0009] When the control unit detects the state during measurement by the load on the load detecting device and the control unit detects the state during measurement, the switching valve is in the second switching state, and the working fluid is pushed from the pump into the second cylinder chamber, and the cylinder is operated. The stem of the device is retracted to further compress the compression spring and lower the support platform to a position where it does not contact the platform. Reading of the weighed value is performed in this state, and thereafter, when the control unit sets the switching valve to the third switching state, the first value is read.
The working fluid is sent to the cylinder chamber by a pump, and the mounting table is quickly separated from the load detecting device.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The weighing device with the shock absorbing device of the present invention is configured as shown in FIG. A platform scale 7 as a load detecting device is mounted on a fixed side 8, and the platform 1 on which the object 9 is placed is in a standby state as shown in FIG.
It is lifted from the platform scale 7 by 10.

The support 10 is pushed up by a compression spring 11, and a cylinder device 12 is interposed in parallel with the compression spring 11. Among the two cylinder chambers of the cylinder device 12, the cylinder chamber compressed by the load from the mounting table 1 is defined as a first cylinder chamber a, and the cylinder chamber opposite to the first cylinder chamber a is defined as a second cylinder chamber b. Then, the first cylinder chambers a of the plurality of cylinder devices 12 are connected to each other by the first pipe 13, and the second cylinder chambers b are connected to each other by the second pipe 14.

The flow of the working fluid in the first and second pipes 13 and 14 is selected by a solenoid valve 15 having a three-way return position and five directions as a switching valve. Switching is performed based on the weighing signal S.

The total upward force generated by the compression spring 11 is “F”, and the weight of the platform 1 is “W ₀ ”.
“F> W ₀ ”, and in a standby state before the object to be measured is loaded on the mounting table 1,
As shown in FIG.
Lifted from and separated. Here the support base 10
Is included in “W ₀ ”.

In this standby state, the solenoid valve 15 is in the neutral position P0, and the first pipe 13 is connected to the throttle valve 16
And a tank 17 via a solenoid valve 15. Throttle valve
A check valve 19 is connected in parallel to 16 in a direction for inhibiting the flow of the working fluid 18 from the first pipe 13 toward the tank 17. The second pipe 14 is connected to a tank 17 via an electromagnetic valve 15.

When the object 9 is loaded on the mounting table 1 in this standby state, the supporting table 10 is pushed down against the bias of the compression spring 11, and the stem 20 of the cylinder device 12 is moved to the first cylinder chamber. a, the working fluid in the first cylinder chamber a is gently returned to the tank 17 at a flow rate defined by the throttle valve 16 via the pipe 21, and the pipe 22 is connected to the second cylinder chamber b.
The working fluid is sucked up from the tank 17 via the electromagnetic valve 15 and the mounting table 1 is gradually lowered onto the platform scale 7, and the mounting table 1 is loaded on the platform scale 7 as shown in FIG.

When the control unit 23 detects that the weighing value of the weighing platform 1 is loaded on the weighing platform 7 and the weighing value of the weighing platform gradually increases from the load "zero" and the weight of the weighing platform reaches a specified weight near the zero point, the solenoid valve is activated.
15 is switched to the first position P1 shown in FIG.

When the solenoid valve 15 is switched to the first position P 1, the working fluid is pushed from the pump 24 into the second cylinder chamber b via the second pipe 14 and resists the urging of the compression spring 11. The support base 10 descends further slowly, and the support base 10
Moves away from the mounting table 1 and the entire load of the DUT 9 acts on the platform scale 7.

In this state, the balance weight value of the platform scale 7 is used as a measured value. As described above, since the working fluid 18 is discharged into the tank 17 only at the speed specified by the throttle valve 16, even when the object 9 is roughly loaded on the mounting table 1, the working fluid 18 No impact force acts on the platform scale 7
Can be protected. Also, as shown in FIG.
At the time of reading the weighed value, the support table 10 is completely separated from the mounting table 1 and is not in contact with it, so that high-accuracy measurement can be expected despite obtaining the buffer function as described above.

In this embodiment, when the control unit 23 detects that the weighed value of the platform weigher 7 has been balanced outside the vicinity of the zero point, after a specified time or immediately after holding the weighed value, the solenoid valve 15 is turned on in FIG. Is switched to the second position P2 as shown in FIG.

When the solenoid valve 15 is switched to the second position P2, the discharge port of the pump 24 is connected to the first pipe 13 via the solenoid valve 15 and the check valve 19, and the second pipe 14 is connected to the solenoid valve. Fifteen
And the tank 17 through a pipe 22. Therefore,
The working fluid 18 is sent into the first cylinder chamber a by the pump 24, and the support table 10 is rapidly raised, the platform 1 is lifted, and the platform 1 is separated from the platform scale 7.

The state in which the mounting table 1 has risen to the prescribed position and has been separated from the platform scale 7 is detected by the limit switch 25 shown in FIG. 1, and the control unit 23 reads the detection output of the limit switch 25 and When it is confirmed that 1 has risen to the prescribed position, the solenoid valve 15 is returned to the neutral position P0.

Accordingly, the support 10 rises faster than when it is lowered, lifts the platform 1 from the platform scale 7 and returns to the standby state shown in FIG. 1, so that the next measurement can be performed early.
It is preferable to use a liquid having an appropriate viscosity as the working fluid 18.

In the above embodiment, the detection output of the limit switch 25 is read and the solenoid valve 15 is returned from the second position P2 to the neutral position P0. The same applies to the case where the control unit 23 is configured to detect the elapse of a specified time and to return from the second position P2 to the neutral position P0 after switching from the position P1 to the second position P2.

In the above embodiment, the throttle valve 16 is interposed between the first cylinder chamber a and the solenoid valve 15 so that the first cylinder chamber a
The discharge flow from the pump to the tank 17 is limited, but the same effect can be expected even if the throttle valve 16 is provided in the flow path of the working fluid into the second cylinder chamber b. Also in this case, the check valve 19 is connected in parallel with the throttle valve 16 in a direction that does not hinder the suction of the working fluid into the first cylinder chamber a. Throttle valve 16 in this case
The check valve 19 is shown in FIG.

In the above embodiment, when the control unit 23 detects that the weighed value of the platform scale 7 is balanced at a position other than near the zero point,
Although it has been described that the solenoid valve 15 is automatically switched to the second position P2 after a specified time or immediately after the measured value is held, this is configured to be switched to the second position P2 by a switch operation of an attendant. You can also.

When the measurement is completed and the object 9 is removed from the mounting table 1, the weighing signal S becomes lower than the specified weight, and the control unit 23 detects this state and activates the solenoid valve 15. 2
May be switched to the position P2.

[0027]

As described above, according to the present invention, a compression spring is interposed between a support table on which a mounting table is mounted and a fixed side to lift the above-described table from the force-applying portion of the load detecting device. ,
A cylinder device is interposed between the support table and the fixed side in parallel with the compression spring, and a first cylinder chamber compressed by a load from a mounting table of the two cylinder chambers of the cylinder device and A first switching state in which both of the second cylinder chambers on the opposite side of the second cylinder chamber are communicated with the working fluid tank, and a second cylinder is connected to the discharge port of the pump by communicating the first cylinder chamber with the tank. For switching the flow path of the working fluid between a second switching state in which the chambers are connected and a third switching state in which the second cylinder chamber is connected to the tank and the first cylinder chamber is connected to the discharge port of the pump. A valve is provided, and a throttle valve is provided in a discharge path of the working fluid from the first cylinder chamber or a suction path of the working fluid to the second cylinder chamber, so that the suction of the working fluid into the first cylinder chamber is not hindered. Connected in parallel with the throttle valve A valve is provided, and the switching valve is set to the first switching state during standby, and when a state in which the load detected by the load detection device exceeds the specified weight is detected, the switching valve is set to the second switching state. Since the control unit for switching the switching valve to the third switching state is provided, when the device to be measured is mounted on the mounting table, the support table slowly descends toward the load detecting device at a flow rate per unit time determined by the throttle valve. As a result, it is possible to avoid a situation in which the mounting table is loaded on the load detection device and the impact force applied to the mounting table acts on the load detection device.

Further, when the loading section is loaded on the load detecting device and the control section detects the measuring state, the switching valve is switched, the working fluid is pushed from the pump into the second cylinder chamber, and the stem of the cylinder apparatus is moved. Since the compression spring is retracted to further compress and lower the support platform to a position where it does not contact the platform, the measurement can be performed with the buffer device completely separated from the platform. Since the entire load acts on the load detecting device, measurement with higher accuracy than before can be realized.

When the measurement is completed, the working fluid can be pumped into the first cylinder chamber to raise the support table, and the mounting table can be quickly separated from the load detecting device. This is effective when weighing is required.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a weighing device with a shock absorbing device of the present invention in a standby state.

FIG. 2 is an explanatory diagram showing a progress of a state in which a control unit of the apparatus detects a measuring state.

FIG. 3 is an explanatory diagram of a measurement value reading state of the apparatus.

FIG. 4 is an explanatory diagram of an operation of returning to an initial state after reading of a measurement value of the apparatus.

FIG. 5 is a configuration diagram of a conventional weighing device with a shock absorbing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Load stand 7 Scales [Load detection device] 8 Fixed side 9 DUT 10 Support stand 11 Compression spring 12 Cylinder device a First cylinder chamber b Second cylinder chamber 13 First pipe 14 Second pipe 15 Electromagnetic Valve [Switching valve] 16 Throttle valve 17 Tank 19 Check valve 23 Control unit 24 Pump P0 Neutral position [First switching state] P1 First position [Second switching state] P2 Second position [Third switching state ]

Claims (1)

(57) [Claims] 1. A compression spring is interposed between a support table on which a mounting table is mounted and a fixed side to lift the table from a force-applying portion of a load detecting device, and a space between the support table and the fixed side. A cylinder device is interposed in parallel with the compression spring, and a first cylinder chamber, which is compressed by a load from a mounting table of both cylinder chambers of the cylinder device, and a first cylinder chamber on the opposite side to the first cylinder chamber. A first switching state in which both of the two cylinder chambers communicate with the tank for the working fluid, and a second switching state in which the first cylinder chamber communicates with the tank and the second cylinder chamber is connected to the discharge port of the pump. A switching valve for switching the flow path of the working fluid between a third switching state in which the first cylinder chamber is connected to the discharge port of the pump by connecting the second cylinder chamber to the tank and the first cylinder chamber; Path of working fluid from the second or second cylinder A throttle valve is provided in a suction path of the working fluid into the chamber, and a check valve connected in parallel to the throttle valve in a direction that does not hinder the suction of the working fluid into the first cylinder chamber is provided;
During standby, the switching valve is set to the first switching state, and when a state in which the load detected by the load detection device exceeds the specified weight is detected, the switching valve is set to the second switching state, and then the switching valve is set to the second switching state. A weighing device with an impact buffer provided with a control unit for switching to the switching state of 3.