JP2608653B2 - 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 a first aspect of the present invention, there is provided a weighing apparatus with a shock absorbing device, wherein a cylinder device is interposed between the mounting table and a fixed side, and the above-mentioned table is lifted from a force-applying portion of the load detecting device. A relief valve is interposed in the discharge path of the working fluid from the first cylinder chamber which is compressed by the load from the mounting table of the two cylinder chambers of the cylinder device,
A throttle valve is interposed in the discharge path of the working fluid from the cylinder chamber or the suction path of the working fluid to the second cylinder chamber to reduce the pressure between the discharge port of the pump that sends out the working fluid and the first cylinder chamber. A first switching state in which a working fluid is sucked into a second cylinder chamber of the cylinder device opposite to the first cylinder chamber and a discharge port of the pump are connected to the second cylinder chamber with a valve interposed therebetween. A control valve for switching the switching valve from the first switching state to the second switching state when a measuring state is detected from the weight value of the load detecting device. It is characterized by having been provided.

According to a second aspect of the present invention, there is provided a weighing device with a shock absorbing device, wherein a cylinder device is interposed between the mounting table and a fixed side to lift the above-mentioned table from a force-applying portion of a load detecting device. A relief circuit of a relief type pressure reducing valve is interposed in the discharge path of the working fluid from the first cylinder chamber which is compressed by the load from the mounting table of the two cylinder chambers, and the working fluid from the first cylinder chamber is A throttle valve is interposed in the discharge path or the suction path of the working fluid to the second cylinder chamber, and the pressure reducing circuit of the relief type pressure reducing valve is provided between the discharge port of the pump that sends out the working fluid and the first cylinder chamber. A first switching state in which the working fluid is sucked into the second cylinder chamber on the side opposite to the first cylinder chamber of the cylinder device, and a discharge port of the pump is connected to the second cylinder chamber. Switching state of 2 And a control unit for switching the switching valve from the first switching state to the second switching state when the measuring state is detected from the weighed value of the load detection device. .

[0008]

According to the structure of the first aspect, the discharge port of the pump is connected to the first cylinder chamber via the pressure reducing valve, and in a standby state until the control unit detects that the measurement is being performed, the discharge port of the pump is connected to the first cylinder chamber. The working fluid is pushed in and the cylinder device is extended, and the mounting table is pushed up by the cylinder device and separated from the load detecting device.

When an object to be measured is placed on the mounting table, a compressive force acts on the first cylinder chamber of the cylinder device which pushes up the mounting table, and the first cylinder chamber has a first flow rate per unit time determined by the throttle valve. The working fluid in the cylinder chamber is pushed out, and the platform slowly descends toward the load detector to load the platform on the load detector.

[0010] 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 switched to the second switching state, and the working fluid is pushed from the pump into the second cylinder chamber. When the working fluid is pushed into the second cylinder chamber, the working fluid in the first cylinder chamber is gently discharged through the relief valve and the throttle valve, and the cylinder device continues to retreat gently and does not contact the mounting table. State. Reading of the weighed value is performed in this state.

When the object to be measured is removed from the mounting table, the compressive force acting on the first cylinder chamber from the support table is released, and the switching valve is activated because the weighing signal has decreased to a predetermined weight or less. The state is switched to the first switching state. Thereby, the stem of the cylinder device is extended by the pump pressure acting on the first cylinder chamber via the pressure reducing valve, and the platform is lifted from the load detecting device and separated.

According to the second aspect of the present invention, the relief valve and the pressure reducing valve of the first aspect are constituted by the relief circuit and the pressure reducing circuit of the relief type pressure reducing valve, and operate in the same manner as the first aspect.

[0013]

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 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 lifted from the platform 7 by a cylinder device 10 in a standby state as shown in FIG. ing.

Of the two cylinder chambers of the cylinder device 10, the cylinder chamber compressed by the load from the mounting table 1 is the first cylinder chamber a, and the cylinder chamber opposite to the first cylinder chamber a is the second cylinder chamber. If the chamber b, a plurality of cylinder devices
Ten first cylinder chambers a are connected to each other by a first pipe 11, and second cylinder chambers b are connected to each other by a second pipe 12.

The first pipe 11 is connected to a tank 15 via a relief valve 13 and a throttle valve 14, and is connected to a discharge port of a pump 17 via a non-relieving type pressure reducing valve 16. A solenoid valve 19 as a switching valve is interposed between a pipe 18 between the second pipe 12 and the tank 15 and a discharge port of the pump 17. Switching is performed based on S.

Here, the discharge pressure of the pump 17 is set to "P1
”, The output pressure of the pressure reducing valve 16 is“ P2 ”, and the relief valve 13
The description will be made assuming that the set pressure is “P0” and the sum of the cross-sectional areas of the pistons of the cylinder device 10 is “A”.

In a standby state before the object to be measured is loaded on the mounting table 1, the solenoid valve 19 is in the first position 20 as shown in FIG.
And the second cylinder chamber b communicates with the tank 15 via the pipe 18. Pump 17 discharge pressure "P1
Becomes an output pressure “P2” via the pressure reducing valve 16 and acts on the first cylinder chamber a, generating a pushing force “F” (= P2 · A) exceeding the dead load of the mounting table 1. As a result, the stem 21 of each cylinder device 10 is extended, and the mounting table 1 is lifted in a state of being separated from the platform scale 7.

When the object 9 is loaded on the mounting table 1 in this standby state, a compressive force acts on the first cylinder chamber a due to the load received from the mounting table 1, and the pressure of the first pipe 11 is reduced. The relief valve 13 is opened beyond the set pressure "P0" of the valve 13, and the working fluid in the first cylinder chamber a is slowly discharged to the tank 15 at a set flow rate determined by the throttle valve 14, and the second cylinder chamber b , A working fluid is sucked from the pipe 19 through the solenoid valve 19, and the stem 21 is pushed into the first cylinder chamber a.
The mounting table 1 slowly descends and is loaded on the platform scale 7 as shown in FIG.

When the control section 22 detects that the weighing platform 1 is loaded on the platform weigher 7 and the weighing value of the platform weigher gradually increases from the load "zero", and the control section 22 detects a measuring state at a specified weight near the zero point, the solenoid valve is activated.
19 is switched to the second position 23.

When the solenoid valve 19 is switched to the second position 23 as shown in FIG. 3, the working fluid is pushed into the second cylinder chamber b from the pump 17 via the second pipe 12, and
The stem 21 is further pushed into the first cylinder chamber a, the cylinder device 10 is separated from the mounting table 1 and the entire load of the measured object 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. Since the working fluid is discharged to the tank 15 only at the speed specified by the throttle valve 14 in this manner,
Even when the DUT 9 is roughly mounted on the mounting table 1, no impact force acts on the contact portion of the platform scale 7, and the platform scale 7 can be protected. Further, as shown in FIG. 3, when reading the weighed value, the cylinder device 10 is completely separated from and not in contact with the mounting table 1, so that the buffer function can be obtained as described above. Regardless, high-precision measurement can be expected.

When the measurement is completed in the state shown in FIG. 3 and the object 9 is removed from the mounting table 1, the weighing signal S falls below a specified weight, and the control unit 22 detects this state. The solenoid valve 19 is switched to the first position 20.

The solenoid valve 19 is switched to the first position 20 and the discharge pressure "P1" of the pump 17 is applied to the second cylinder chamber b.
Is stopped, the stem 21 is extended by the output pressure "P2" of the pressure reducing valve 16 acting on the first cylinder chamber a, and the platform 1 is lifted from the platform scale 7 to the standby state shown in FIG. Return.

In the above embodiment, the throttle valve 14 is connected to the first pipe 11
Although it is interposed between the tank 15 and the tank 15, it can be interposed between the tank 15 and the second pipe 12. In the above example, the working fluid circuit is configured by using the relief valve 13 and the non-relieving type pressure reducing valve 16, but this is also achieved by using the relief type pressure reducing valve 16 as shown in FIG. A circuit can be configured, and a relief circuit 25 of a relief type pressure reducing valve 24 is interposed in place of the relief valve 13, and a pressure reducing circuit
26 is provided in place of the pressure reducing valve 16. In this case, the interposition position of the throttle valve 14 is also determined by the tank 15 and the second pipe 12.
Can be interposed between

[0025]

As described above, according to the configuration described in each of the claims, when the object to be measured is mounted on the mounting table, the support table is gently moved at a flow rate per unit time determined by the throttle valve. , The platform is loaded on the load detector, and the impact force applied to the platform can be prevented from acting on the load detector.

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 device is moved. Since it is retracted and retracted to a position where it does not come into contact with the mounting table, measurement can be performed with the buffering device completely separated from the mounting table, and the entire load of the measured object acts on the load detection device, The measurement can be performed with higher accuracy than before.

[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 a configuration diagram of another embodiment.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Load base 7 Scale [Load detection device] 8 Fixed side 9 DUT 10 Cylinder device a First cylinder chamber b Second cylinder chamber 11 First piping 12 Second piping 13 Relief valve 14 Throttle valve 15 Tank 16 Pressure reducing valve 17 Pump 19 Solenoid valve (switching valve) 22 Control unit

Claims (2)

(57) [Claims] 1. A cylinder device is interposed between a platform and a fixed side to lift the platform from a force-applying portion of a load detecting device, and to apply a load from a platform of both cylinder chambers of the cylinder device. A relief valve is interposed in the discharge path of the working fluid from the first cylinder chamber to be compressed, and the relief valve is narrowed to the discharge path of the working fluid from the first cylinder chamber or the suction path of the working fluid to the second cylinder chamber. A second cylinder chamber on the opposite side of the first cylinder chamber of the cylinder device, wherein a pressure reducing valve is interposed between a discharge port of a pump for delivering a working fluid and the first cylinder chamber; A switching valve for switching between a first switching state in which the working fluid is sucked in and a second switching state in which the discharge port of the pump is connected to the second cylinder chamber; When the switching valve is detected, A weighing device with an impact buffer provided with a control unit for switching from the switching state to the second switching state. 2. A cylinder device is interposed between a platform and a fixed side to lift the platform from a force-applying portion of a load detecting device, and to apply a load from a platform of both cylinder chambers of the cylinder device. A relief circuit of a relief type pressure reducing valve is interposed in the discharge path of the working fluid from the first cylinder chamber to be compressed, and the discharge path of the working fluid from the first cylinder chamber or the working fluid to the second cylinder chamber. A pressure reducing circuit of the relief type pressure reducing valve is interposed between a discharge port of a pump for sending out a working fluid and the first cylinder chamber, and a first cylinder of the cylinder device is provided. A switching valve for switching between a first switching state in which the working fluid is sucked into the second cylinder chamber on the opposite side of the chamber and a second switching state in which the discharge port of the pump is connected to the second cylinder chamber; Of load detector A weighing device with an impact buffer, comprising a control unit for switching the switching valve from a first switching state to a second switching state when a measuring state is detected from the weighing value.