JPH034095B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a weight detection device that is equipped with a buffer mechanism for overload prevention and utilizes the strain principle of an elastic body.

[Prior art]

As a weight detection device equipped with a buffer mechanism for overload prevention, many similar devices have been proposed, such as the technique disclosed in Japanese Utility Model Application Publication No. 54-171370. However, in all of these basic configurations, as shown in FIG. 7, fixed overload stoppers 2, 2 are installed on the pedestal 5 with a predetermined gap below the periphery of the weighing pan 1. Although this method is effective for static overload prevention, it cannot function effectively against dynamic overload. That is, in response to a static overload, only a load corresponding to the strain in the predetermined gap acts on the weight sensor section 3, and other loads are supported by the fixed overload stoppers 2, 2. Therefore, overload on the weight sensor section 3 is prevented. On the other hand, as shown in FIG. 8, when an impact load is applied to the weighing pan 1 due to a dynamic overload, for example, the object to be weighed 4 is dropped, the inertia of the object to be weighed 4 causes the weighing Since the deformation of the plate is large, a strain greater than the predetermined gap occurs in the weight sensor section 3, and an overload is applied to the weight sensor section 3. As a result, problems arise in the durability of the scale, such as the strain gauge attached to the weight sensor section 3 peeling off. Furthermore, when an impact load is applied, the vibration damping of the weight sensor section 3 is delayed due to the above-mentioned inertia.
This method has the disadvantage that it takes time from placing the object 4 to be weighed to measuring the true weight of the object 4 to be weighed.

[Purpose of the invention]

The present invention has been made in consideration of the above-mentioned conventional problems, and reduces the influence on the weight sensor section not only in response to static overload but also in response to dynamic overload. The purpose of the present invention is to provide a weight detection device that shortens the time required to reach a stable weight value by improving the durability of the weight scale and speeding up the vibration damping of the weighing mechanism after placing an object to be weighed. It is something.

[Structure of the invention]

The weight detection device according to the first aspect of the present invention includes a weighing mechanism section installed on a pedestal, and a weighing pan installed on the weighing mechanism section, and an overload receiving device is provided between the pedestal and the weighing pan. The weighing pan is configured to be able to place the object to be weighed with the weighing pan supported by the lifting device, and to avoid deformation of the weighing pan when placing the object to be weighed. It is characterized by the fact that

The weight detection device according to the second aspect of the present invention includes: a weight sensor section provided on a pedestal; a weighing pan support section connected to the weight sensor section and having upper parts of protrusions at both ends made of an elastic body; a vibration suppressing mechanism interposed between the weighing pan and the center recess of the weighing pan support, and the upper end support is arranged between the pedestal and the weighing pan with the elastic A lifting device for overload reception made of an elastic body with a spring constant larger than that of the body is provided, and the weight sensor section and the lifting device for overload reception are configured to detect and analyze the weight and control the lifting and lowering of the lifting device. The structure is connected by a detection control means that forms an object to be weighed, and avoids deformation of the weighing pan when placing an object to be weighed. The present invention is characterized in that it is configured to further reduce the load on the metering mechanism due to overload.

The weight detection device according to the third aspect of the present invention includes: a weight sensor section provided on a pedestal; a weighing pan support section connected to the weight sensor section and having upper parts of protrusions at both ends made of an elastic body; A vibration suppressing mechanism is provided between the weighing pan and the center recess of the weighing pan support, and the upper end support is located at a height between the pedestal and the weighing pan. A lifting device for overload reception having a load-bearing weight sensor is provided, and a detection control means detects and analyzes the weight of the weight sensor section and the lifting device for overload reception, and controls the lifting and lowering of the lifting device. The structure is such that the upper end support part of the lifting device, which has a high load-bearing weight sensor, supports most of the impact load, reducing the load on the weighing mechanism and also being able to detect the impact. It is characterized by:

[Embodiment of the first and second inventions] An embodiment of the first and second inventions is shown in FIGS. 1 to 5.
The explanation is as follows based on the figure.

A weight sensor section 15 is provided on the pedestal 14. A weighing pan support section 13 is connected to the weight sensor section 15, and the upper portions of the protrusions at both ends of the weighing pan support section 13 are elastic bodies 13a, 13 made of rubber blocks, air springs, coil springs, etc. with a relatively small spring constant K _A.
It is formed by a. The elastic bodies 13a, 13a
A weighing pan 11 is fixed on the top. A vibration suppressing mechanism 16, 16 consisting of a shock absorber, an oil damper, an air damper, etc. is interposed between the central recess of the weighing pan support 13 and the weighing pan 11. A weighing mechanism section 17 consisting of the weight sensor section 15, weighing pan support section 13, and vibration suppressing mechanisms 16, 16 is installed between the center of the weighing pan 11 and the pedestal 14.

Overload stoppers 18, 18 are interposed between the weighing pan 11 and the pedestal 14 on both sides of the weighing mechanism section 17, as lifting and lowering devices for receiving overloads. The overload stoppers 18, 18 have elevating mechanisms 18b, 18b of a motor-driven cam type, air or hydraulic cylinder type, etc. on support shafts 18a, 18a provided on the frame 14, and these elevating mechanisms 18b, 1
On 8b, there is an elastic body 18c, 1 with a large spring constant K _B consisting of a rubber block, air spring, coil spring, etc.
8c is provided. These elastic bodies 18c, 18
c is movable up and down by the lifting mechanisms 18b, 18b, and at its upper limit position, the elastic bodies 18c, 18
c is configured so that the upper end thereof can come into contact with the back surface of the weighing pan.

The lifting mechanism 18b includes the weight sensor section 15
and is connected via a control device 19 as a detection control means. The control device 19 includes the weight sensor section 15
receive the electrical signal detected by the input means 19a,
The waveform analysis means 19b determines the change in gravity due to the placement of the object to be weighed 20 and the subsequent stabilization of the weight,
The output means 19c is configured to transmit a lifting signal to the lifting mechanism 18b to control the lifting and lowering of the elastic bodies 18c, 18c, and the weight value outputting means 19d outputs a measured value.

In the above configuration, first, when nothing is placed on the weighing pan 11 as shown in FIG.
is at its upper limit position and in contact with the weighing pan 11.

Next, as shown in FIG. 2, the moment when the object to be weighed 20 is placed on the weighing pan 11 is as follows. An impact load Wmax that is considerably larger than the weight W _O of the object to be weighed acts on the weighing pan 11 .

In the present invention, since the overload stoppers 18, 18 are in a state of supporting the weighing pan 11 from the beginning, deformation of the center portion of the weighing pan 11 due to impact can be ignored compared to the conventional example, and the elastic bodies 13a, 13a
Assuming that the displacement amounts of the elastic bodies 18c and 18c due to impact are the same, the load W _A acting on the weight sensor section 15 via the weighing pan support section 13 is W _A = Wmax·K _A / K _A + K _B. Become. It is assumed that the load acting on the weight sensor section 15 via the vibration suppressing mechanisms 16, 16 can be ignored. That is, the elastic body 1 is such that K _A ≪ K _B
By setting the spring constants of the elastic bodies 3a, 13a and the elastic bodies 18c, 18c, it is possible to set W _A <<Wmax, so the load W acting on the weight sensor section 15 can be kept considerably smaller than the impact load Wmax. This makes it possible to reduce the influence of the impact load Wmax on the weight sensor section 15.

The load W _A applied to the weight sensor section 15 is converted into an electrical signal, and the input means 1 of the control device 19
9a. The generation of W _A , that is, the placement and loading of the object to be measured 20, is performed by the waveform analysis means 19b.
A subsequent decay of W _A is detected. After waiting for the load W _A to attenuate, the output means 19c transmits a signal instructing the lifting mechanism 18b, 18b of the overload stoppers 18, 18 to lower the elastic bodies 18c, 18c, and the elastic bodies 18c, 18c It moves away from the weighing pan 11 and shifts to the state shown in FIG.

FIG. 3 shows a state in which the true weight W _O of the object to be weighed 20 is loaded onto the weight sensor section 15. As shown in FIG. In this state, as mentioned above, W _A is greatly relaxed compared to Wmax, so the vibration amplitude of the measuring mechanism section 17 due to the impact is also controlled to be small, but some vibration components still remain. . This residual vibration component is quickly damped by the vibration suppression mechanisms 16, 16. When this vibration has completely subsided and the waveform analysis means 19b confirms that the load applied to the weight sensor section 15 has stabilized, the true weight of the object to be weighed 20 is determined.
W _O is output by the weight value output means 19d, and a signal for raising the elastic bodies 18c, 18c is transmitted by the output means 19c to the lifting mechanisms 18b, 18b of the overload stoppers 18, 18. , the elastic bodies 18c, 18C rise to their upper limit positions, hold the weighing pan 11, and return to the state shown in FIG. 1. At this time, the object to be weighed 20 may be removed from the weighing pan 11, or the next object to be weighed 20 may be placed on the weighing pan 11 without being removed and weighed in the same manner as described above. In addition, the object to be measured 2
Whether or not 0 is placed can be determined by detecting W _A as described above, so no extra sensor is required for this purpose.

FIG. 4 shows the weight sensor section 15 in this embodiment.
This figure shows an example of load fluctuations compared to the conventional example, and in this example, the impact load on the weight sensor section 15 due to the impact load when placing the object to be weighed is significantly reduced compared to the conventional example. As the load changes, the load fluctuations also attenuate quickly, and as shown in the figure,
The time required from placing the object to be weighed to measuring its true weight is also significantly shorter than in the conventional example.

FIG. 5 is a flowchart showing the operation process of the waveform analysis means 19b described above in this embodiment, in which the overload stopper lowering signal is output after the impact load W _A is attenuated, and the true weight value W is output after the weight of the weighed object is stabilized. _O
and the process of outputting an overload stopper rise signal.

[Embodiment of the first and third inventions] An embodiment of the present invention will be described below based on FIG. 6. Incidentally, corresponding members having the same functions as those in the embodiment of the second invention are given the same reference numerals.

At the tips of the overload stoppers 18, 18, in place of the elastic bodies 18c, 18c in the embodiment of the second invention, high load-bearing weight sensor sections 30, 30 made of load cells or the like are provided. The high load-bearing weight sensor parts 30, 30 detect the impact when the object to be weighed 20 is placed on the weighing pan 11, wait for this impact to attenuate, and then The high load-bearing weight sensor parts 30, 30 are configured to be able to be lowered by lifting mechanisms 18b, 18b provided under the sensors 30, 30. The rest of the structure is the same as the embodiment of the second invention.

In the above configuration, the high load capacity weight sensor section 3
The spring constants of 0 and 30 are larger than the spring constants of the elastic bodies 18c and 18c in the embodiment of the second invention and are almost solid, so that at the moment the object to be weighed 20 is placed on the weighing pan 11, Most of the load for the impact load Wmax acting on the weighing pan 11 is supported by the high load-resistant weight sensor sections 30, 30, and the weight sensor section 15 of the weighing mechanism section 17 is mostly affected by the overload such as the above-mentioned impact load. Never.

Due to the detection of the impact by the high load capacity weight sensor units 30, 30, the high load capacity weight sensor unit 3
0 and 30 are lowered, and the weight sensor section 15 of the weighing mechanism section 17 outputs the true weight W _O of the object to be weighed 20 by the same means as in the above embodiment.
The high load-bearing weight sensor sections 30, 30 rise to their upper limit positions and return to the state before the object to be weighed 20 was placed.

〔Effect of the invention〕

The weight detection device of the first invention supports the weighing pan at the upper end support part of the lifting device for overload receiving when the object to be weighed is placed, and after the vibration due to the impact load is attenuated, the weighing pan is supported by the upper end support part. Since the structure is configured such that the weighing mechanism can measure the true weight by lowering the weight sensor, the influence of dynamic overload on the weighing mechanism can be reduced, protecting the weight sensor and ultimately improving weight detection. It is possible to significantly improve the durability of the device. In addition, the vibration damping of the weighing mechanism after placing the object to be weighed can be accelerated and the time required to reach a stable measurement value can be shortened, and the improved durability can tolerate rough handling of the object to be weighed. It is possible to achieve the effect that work efficiency can be greatly improved.

Since the weight detecting device of the second invention is equipped with a lifting device for overload reception in the weight detecting device of the first invention, the durability and workability of the weight detecting device of the first invention are improved. The same effect as that of improvement can be achieved. Moreover, in the second aspect of the present invention, the above-mentioned effects are even more effective because the metering mechanism is configured to further reduce the load on the metering mechanism due to overload as described above. Furthermore, since the weight detection device of the present invention is configured so that a part of the weight when an object to be weighed is placed on the weighing mechanism, a special sensor is used to detect the placement of the object on the weighing pan. It also produces effects that are said to be unnecessary.

The weight detecting device of the third aspect of the present invention can achieve the same effects as the above-mentioned second aspect, such as improving the durability and workability of the weight detecting device seen in the first aspect. In particular, in the third aspect of the present invention, most of the impact load generated when placing an object to be weighed is supported by a high load-bearing weight sensor section that can withstand overload, thereby maximally reducing the influence of overload on the weight sensor section. Therefore, the weight sensor section is more completely protected against overload than the second invention. In addition, the structure is configured so that overload and normal load can be detected by using two weight sensors with different load capacities, which increases the lifespan of the weight sensor and improves its economic efficiency. can.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention;
2 is an explanatory diagram of the configuration showing the moment when the object to be measured is placed in FIG. FIG. 5 is a flowchart showing the waveform analysis means of the second invention, FIG. 6 is an explanatory diagram showing the main part configuration of an embodiment of the third invention, 8 and 8 are respectively explanatory diagrams of the configuration of the conventional example. 11 is a weighing pan; 13 is a weighing pan support; 13a;
18c is an elastic body, 14 is a pedestal, 15 is a weight sensor section, 16 is a vibration suppression mechanism, 17 is a weighing mechanism section, 1
8 is an overload stopper, 18b is a lifting mechanism, 19 is a control device, 19a is an input means, 19b is a waveform analysis means, 19c is an output means, 19d is a weight value output means, 20 is an object to be measured, 30 is a high load capacity This is the weight sensor section.

Claims (1)

[Claims] 1. A measuring mechanism installed on a pedestal, and a weighing pan provided on the pedestal, and an elevating device for receiving overload between the pedestal and the weighing pan. A weight detection device characterized by being provided with. 2. A weight sensor section provided on the pedestal, a weighing pan support section connected to the weight sensor section and having upper parts of protrusions at both ends formed of an elastic body, a weighing pan fixed on the elastic body, A vibration suppression mechanism is provided between the center recess of the weighing pan support and the weighing pan, and the upper end support is formed of an elastic body having a larger spring constant than the elastic body between the pedestal and the weighing pan. The weight sensor unit and the overload receiving lifting device are connected to each other for weight detection and
A weight detection device, characterized in that it is connected to a detection control means for analyzing and controlling the elevation of the elevating device. 3. a weight sensor section provided on a pedestal; a weighing pan support section connected to the weight sensor section and having upper portions of protrusions at both ends formed of an elastic body; and a weighing pan placed on the elastic body; A vibration suppressing mechanism is provided between the center recess of the weighing pan support and the weighing pan, and the upper end support has a high load capacity weight sensor between the pedestal and the weighing pan. A weight detection device characterized in that the weight sensor section and the overload receiving lifting device are connected by a detection control means for detecting and analyzing weight and controlling the lifting and lowering of the lifting device. .