SK1352020A3 - Device for elimination of unwanted load and overload of strain gauge - Google Patents

Abstract

The device for eliminating unwanted load and overload of the strain gauge consists of a fixed part of the device, which is formed by the support plate (1) of the supporting structure, the clamp (2) of the strain gauge, the guide bush (3), the cage (8) of the guide, the main shaft (7) and a delimiting element (10). In the fixed part of the device to eliminate unwanted loading and overloading of the strain gauge sensor, a moving part is stored, which consists of a limiting screw (4), a support piston (5), a cam mechanism (6) and a push/pull piston (9). By means of the movements of the moving part of the device, the strain gauge sensor (11) is protected against unwanted passive loading when it is not active, and at the same time it is protected against unwanted overloading of the strain gauge sensor directly during its active operation, i.e. in the measurement process.

Description

The field of technology

The invention relates to a device for eliminating unwanted passive loading as well as unwanted overloading of the strain gauge sensor during active operation. The invention belongs to the field of engineering industry.

Current state of the art

Tensometric sensors are currently an extended group of sensors used mainly for weighing objects or systems in technical applications. Very often, high demands are placed on their application (weighing accuracy), which current existing strain gauges are able to meet due to their design. An important factor affecting the accuracy of the application of strain gauge sensors is the unwanted phenomena of their overloading (loading with a greater weight compared to the weight for which they are designed) and also an unwanted phenomenon is their passive loading by other structures or objects outside the time of their primary purpose (outside the weighing process).

There are known solutions for the protection of the weighing sensor, for example the system resulting from the monitoring and acquisition of weighing data from the sensor, the calculation of the lifting force and the subsequent assessment with respect to the overload values described in the patent document CN111174888 (A). Another well-known way of protecting the sensors is the addition of elements interfering with the measurement process, as for example according to the patent document CN105021370 (A), where an interfering rod secured with a lock nut is connected to the resistance sensor. Alternatively, an invention is known according to the patent document CN110207889 (A), where a movable connection by means of guide screws and shafts, springs and linear bearings interrupts the measurement, the sensor moves down and thus prevents its damage.

The VEIGROUP Group markets TRUELOAD products under the Vei On-board Weighing brand, an overload protection and payload optimization system as a solution for load and overload monitoring.

At present, there are no available solutions that eliminate unwanted passive loading of strain gauge sensors integrated in technical devices, or they are not integrated into structural devices equipped with strain gauges, and these structural devices also do not have the possibility of automating the elimination of unwanted passive load and unwanted overload during the active operation of strain gauge sensors outside of the weighing process itself.

The essence of the invention

The mentioned shortcomings of the state of the art are eliminated by the present invention, the essence of which is the design of a device for eliminating unwanted load and overload of the strain gauge sensor, which is characterized above all by its compact dimensions, full integration into the design of the technical device, resistance to failures and complete automation of operation. The design of the structure includes the possible need for variability of the technical design depending on the specific design solution of the application of the strain gauge in the technical equipment, as well as the need for variability resulting from the size and type of the strain gauge used.

The device is structurally assembled from a fixed and a movable part. Through the moving part, the working movements of the device are realized, the aim of which is to modify the function of the device depending on the activity, or of inactivity, of the built-in strain gauge sensor, which is the object of protection against unwanted passive loading in the time outside of active activity and at the same time the object of protection against unwanted overloading of the strain gauge sensor during its active operation, i.e. j. during measurement. The initiation of the activity and the entire working cycle of the moving part of the device are realized by the drive, which, due to the universality of the solution, is not part of the device to eliminate unwanted load and overload of the strain gauge sensor. The condition for choosing a suitable drive is the necessity to carry out a linear work movement at the output, and at the same time the drive must be equipped with means to ensure a fixed position (e.g. a brake) to prevent unwanted movement outside the time of active operation of the device. Suitable solutions are pneumatic, electromechanical, etc. linear drives.

The essence of the invention can be described in two positions of the device, depending on the activity or strain gauge sensor inactivity:

1. The strain gauge sensor is out of active operation, i.e. the protection of the strain gauge sensor against unwanted passive loading during the time outside the implementation of the measurement process is ensured.

SK 135-2020 A3

The working position with the location of the supporting element of the moving part of the device is in the upper limit position. The strain gauge sensor and the support element of the moving part of the device are in contact with each other. Protection is thus ensured by creating a fixed support point through a support element that is part of the moving part of the device. At the same time, reaching the upper limit position of the support element ensures that the moving part of the device is placed in a position that allows the complete transfer of the compressive force acting on the protected strain gauge to the device, thus ensuring the protection of the strain gauge against rapid wear. A necessary condition for locking the position is the activation of the protective brake on the drive initiating the working movements of the device.

2. The strain gauge sensor is in active operation, i.e. protection of the strain gauge sensor against unwanted overloading during the measurement (weighing) process is ensured. The working position with the location of the supporting element of the moving part of the device is at the bottom dead center. The strain gauge and the support element of the moving part are not in contact with each other - a working gap is ensured. When the strain gauge sensor is overloaded in the measurement (weighing) process, the working gap between the strain gauge sensor and the support element will disappear. Protection is provided by creating a fixed support point through a support element that is part of the moving part of the device. At the same time, reaching the lower limit position of the support element ensures that the movable part of the device is placed in a position that allows the complete transmission of the pressure force acting on the protected strain gauge in the event of its overloading into the device, thus ensuring the protection of the strain gauge against potential damage. The device thus prevents unwanted deformation of the strain gauge sensor (outside the working range) when it is overloaded. A necessary condition for locking the position is the activation of the protective brake on the drive initiating the working movements of the device.

Overview of images on drawings

Figure 1 shows a front view of the device for eliminating unwanted loading and overloading of the strain gauge, with the strain gauge located outside of the working activity, i.e. the device is in a state where it provides protection against unwanted passive loading.

Figure 2 shows a side view of the device for eliminating unwanted loading and overloading of the strain gauge.

Figure 3 shows a cross-section of the assembly of the device for eliminating unwanted loading and overloading of the strain gauge, while the strain gauge is located outside of the working activity, i.e. the device is in a state where it provides protection against unwanted passive loading.

Figure 4 shows a front view of the device for eliminating unwanted loading and overloading of the strain gauge, while the strain gauge is in the working phase, i.e. the device is in a state where it provides protection against unwanted overloading of the strain gauge sensor during measurement.

Examples of implementation of the invention

The device for eliminating unwanted loading and overloading of the strain gauge sensor is structurally assembled from a fixed and a moving part. The fixed part of the device is formed by the supporting plate 1 of the supporting structure, the attachment 2 of the strain gauge 11, the guide sleeve 3, the guide cage 8, the main shaft 7 and the upper limiting element 10. The moving part of the device is stored in the fixed part of the device, formed by the limiting screw 4, the supporting piston 5, cam mechanism 6 and push/pull piston 9.

The working movement of the moving part of the device is composed of the vertical movement PV, which is performed by the limiting screw 4 and the support piston 5, the rotary movement PR, which is performed by the elements of the cam mechanism 6, and the horizontal movement PH, performed by the movement of the push/pull piston, which is initiated by an external drive.

After installation of the device, the upper point of stabilization of the fixed strain gauge sensor 11 is set by the stop screw of the upper delimiting element 10 in the state of mutual contact, i.e. j. supports.

The lower point of stabilization of the fixed strain gauge sensor 11 in the state of mutual contact is set by the limiting screw 4 after the installation of the device, i.e. j. support, which also determines the upper limit position of the limit screw 4.

The principle of the device's work consists in the fact that during the time when the tensiometric weighing process is not taking place

SK 135-2020 A3 by sensor 11, t. j. the strain gauge 11 is passively loaded by the weight of the structure placed on it, the limit screw 4 ensures a firm fixation of the strain gauge 11. The limit screw 4 is in this limit state in the upper limit position, which is reached by the action of the entire moving part of the device, i.e. in the time outside the active time of use of the strain gauge sensor 11, it fully transmits the pressure acting on the strain gauge sensor 11 by the weight of the structure placed on it, and thus ensures the elimination of the passive load of the strain gauge sensor 11.

In the process of weighing using strain gauge 11, i.e. j. during the active time, the limiting screw 4 reaches the lower limit position by the action of the entire moving part of the device, which creates a working gap and ensures the protection of the strain gauge sensor 11 against its overload, because the limiting screw 4 in the lower limit position creates a fixed support point for the strain gauge sensor 11 eliminating its deformation in case of overload in active time, i.e. j. during measurement.

Industrial applicability

The proposed invention is intended to eliminate the passive load of the strain gauge sensor in the time outside of their active use. At the same time, it creates a system of protection against unwanted overloading of strain gauges during their use, thereby protecting them from damage. The present invention is fully automated and has the possibility of full integration into industrial solutions.

SK 135-2020 A3

List of relationship tags

Support plate of the supporting structure

Tensometric sensor attachment

Guide sleeve

4 Limiting screw

Support piston

Cam mechanism

Main shaft

Wire cage

9 Push/pull piston

Upper bounding element

Tensometric sensor

PV Vertical movement

PH Horizontal movement

PR Rotational movement

Claims (4)

1. A device for eliminating unwanted load and overload of the strain gauge sensor, characterized by the fact that it consists of a fixed part of the device, which is formed by the support plate (1) of the support structure, the attachment (2) of the strain gauge sensor (11), the guide sleeve (3), the guide cage (8), the main shaft (7) and the upper delimiting element (10) with a stop screw for stabilizing the fixed strain gauge sensor (11) in the state of support, while the movable part of the device formed by the delimiting screw (4) is stored in the fixed part of the device, bearing piston (5), cam mechanism (6) and push/pull piston (9). 2. Device for eliminating unwanted load and overload of the strain gauge sensor according to claim 1, characterized in that during the active operation of the strain gauge sensor (11) the limiting screw (4) is set in the lower limit position, while between the strain gauge sensor (11) and the moving part device, a working gap is created and the demarcation screw (4) represents a fixed support point for the strain gauge (11) to prevent its deformation when overloaded during active operation. 3. Device for eliminating unwanted load and overload of the strain gauge according to claim 1, characterized in that, outside of the active operation of the strain gauge (11), the limit screw (4) is set in the upper limit position to eliminate the passive load of the strain gauge (11). 4. Device for eliminating unwanted load and overload of the strain gauge according to claim 1, characterized in that it is designed as an additional device of the strain gauge (11) to create a compact unit suitable for installation at the measurement location.