DE202007019504U1 - Gas spring with measuring means and means for monitoring at least one occurring within and / or on a gas spring physical quantity - Google Patents

Abstract

Gas spring (1), in particular for receiving strokes in a tool or in a machine, wherein one or more measuring means for monitoring at least one within and / or on the gas spring (1) occurring physical quantity and wherein the measuring means is a pressure sensor or a combined pressure - / Temperature sensor and / or a temperature sensor characterized in that the measuring means have a mains-independent power supply.

Description

The invention relates to a gas spring, in particular for receiving strokes in a tool or in a machine. Furthermore, the invention relates to a device for monitoring at least one occurring within and / or on a gas spring physical quantity.

Gas springs are pneumatic springs that use a pressurized gas to provide a spring force. The gas spring acts as a hydropneumatic adjusting element. Gas springs generally consist of a pressure tube, a piston rod and a piston.

The gas spring is filled with a compressed gas. The gas exerts on the piston a force which is used as restoring force of the gas spring. The restoring force can be precisely determined by the choice of a suitable gas or gas mixture and the setting of a certain filling pressure.

Usually, the piston has at least one small opening through which the compressed gas can flow to the other side of the piston. This results in not only a restoring force, but also a particularly advantageous damping effect of the gas spring.

Such gas springs are to be found, for example, in office chairs or as holding device-en of trunk lids in motor vehicles.

Furthermore, gas springs of the type mentioned are used to provide in tools or machines both a restoring force and a certain damping effect. These may in particular be machines that perform a repetitive stroke movement. Such a lifting movement is characterized by a recurring reciprocating motion of a movable component, wherein the position of the two dead centers of the lifting movement generally does not change.

In such use in tools or machines, however, it may be due to external and / or internal influences to change the suspension and / or damping characteristics of a gas spring come. As the temperature of the spring increases, the internal pressure of the trapped gas increases simultaneously. This changes the suspension characteristics. In addition, the viscosity of the trapped fluid changes as a result of mechanical stress as well as due to the influence of temperature, as a result of which a change in the damping characteristic mainly occurs.

In gas springs according to the prior art, the aforementioned changes are unpredictable. If a deterioration of the damping and / or suspension characteristic occurs, this can not be attributed to a discrete physical phenomenon in a known gas spring. The user of the gas spring is limited to the application of empirical findings.

The present invention is therefore based on the object to provide a traceability and predictability of the use behavior of gas springs depending on the particular conditions of use.

This object is achieved with respect to a gas spring with the features of claim 1. Thereafter, a gas spring of the type mentioned is further developed and designed such that one or more measuring means are provided for monitoring at least one occurring within and / or on the gas spring physical quantity.

According to the invention, it has been recognized that monitoring of physical variables inside and / or on gas pressure springs enables a precise analysis of the instantaneous use behavior. The operational behavior determined in the respective operating situation, d. H. in particular, the damping and suspension characteristics of the gas spring, for example, can be attributed to currently prevailing pressure and temperature conditions in the gas spring. So can always be a correlation of the operational behavior of the gas spring with the current environmental conditions.

Furthermore, it is possible for the user, based on measured physical parameters - in particular pressure and / or temperature - to predict the performance characteristics of the gas spring as a function of certain ambient or operating conditions. Therefore, a suitable gas spring can be selectively selected for the particular intended purpose.

Finally, with the gas spring according to the invention, incidents or damage to the spring itself or else to the machine which contains the spring can be detected. For example, if the dead center of the lifting movement of the machine adjusted, this can be determined directly from a different pressure value within the gas spring. Furthermore, damage to the gas spring itself (for example, leakage) can be detected by abnormal pressure or temperature values, even if the spring is not accessible or visible from the outside.

Consequently, a gas spring is provided, in which a traceability and predictability of the use behavior is realized depending on the respective conditions of use.

In a particularly preferred manner, the gas spring according to the invention has a pressure sensor or a combined pressure / temperature sensor. The gas spring may also have a plurality of pressure sensors and / or a plurality of pressure / temperature sensors. These can be distributed over the length of the gas spring, for example. Furthermore, it is conceivable to provide a pressure sensor on each side of the piston. These pressure sensors measure the internal pressure of the gas spring, namely the pressure of the compressed fluid within the cylinder.

In a further embodiment, as an alternative or in addition to the mentioned pressure sensor, the gas pressure spring also has one or more temperature sensors. Such temperature sensors can decrease both the temperature of the surface of the gas spring and the temperature of the compressed gas within the spring. This makes it possible to determine a correlation between the internal and external temperature of the gas spring in a particularly advantageous manner.

In a particularly preferred embodiment, the measuring means of the gas spring on a network-independent power supply. This eliminates a cabling effort. The power supply can be accomplished by batteries, accumulators or possibly also inductively.

In a further embodiment, the measuring means of the gas spring on a memory for measurement data. In this embodiment, if necessary, an evaluation or display unit for the measurement data can be dispensed with. Stored measured values can be interrogated and displayed periodically or continuously.

• – eine oder mehrere erfindungsgemäße Gasdruckfedern,
• – eine oder mehrere Auswerteeinheiten, und
• – ein oder mehrere Datenübertragungsmittel zur Übertragung von Daten zwischen dem Messmittel und der Auswerteeinheit.

With respect to a device for monitoring at least one occurring within and / or on a gas spring physical quantity, the above object is achieved with the features of claim 6. Thereafter, such a device according to the invention comprises:

• One or more gas pressure springs according to the invention,
• - one or more evaluation units, and
• - One or more data transmission means for transmitting data between the measuring means and the evaluation unit.

In accordance with the invention, the device allows the monitoring of one or more physical measured variables occurring within and / or on one or more gas pressure springs. For this purpose, the use of a gas pressure spring according to the invention is initially provided, which has at least one measuring means. The measured data are forwarded with one or more data transmission means to one or more evaluation units. The display and further processing of the data can be made directly in the evaluation unit or in other optional devices.

With the device according to the invention a complete monitoring of the operational behavior of gas springs is realized. Furthermore, the measured values obtained can be used to enable a traceability and predictability of the operational behavior of the gas spring as a function of the respective conditions of use.

The evaluation unit preferably has a microcontroller. As a result, a small size, low energy consumption and a low-cost provision of the evaluation is possible.

With regard to the most cost-effective solution, the data transmission medium between the gas spring and the evaluation unit can have one or more conductors, in particular cables, and / or one or more coupled conductor tracks (bus). The individual linkage of each individual measuring device (sensor) with the evaluation unit represents the cheapest option, but goes hand in hand with a high amount of wiring. Furthermore, the plurality of cables require corresponding space within the device. Therefore, in limited space and a corresponding number of measuring means (sensors), the use of coupled tracks, d. H. from bus systems.

Such a bus system can operate according to the CANopen protocol and / or the PROFIBUS protocol. In principle, however, the use of other known communication protocols is conceivable.

With regard to the aforementioned embodiment, a development is proposed in which a CAN data logger is provided, with which measurement data can be stored. This CAN data logger can store measured data, for example, on a memory card. The CAN data logger can be configured so that it merely passes on error states to an optionally available programmable logic controller (PLC). On the basis of the recorded measured value history, it is thus also possible to ascertain certain tendencies.

In a particularly preferred development of the device according to the invention, data can be transmitted by radio waves to the data transmission means. In other words, data transmission means are provided which transmit the measured value data from the measuring means of the gas pressure springs by radio to the evaluation unit. Such data transmission means may be provided alternatively or in addition to the aforementioned wireline data transmission means. If only data transmission means operating by radio are provided, the wiring effort is eliminated. In addition, the space required within the facility decreases. Furthermore, the gas pressure springs can be used hermetically shielded, but measured value signals can be transmitted by radio to the evaluation unit.

With respect to the aforementioned embodiment, it is preferable that data in the short-range GHz radio wave range, particularly in the ISM band between 2.402 GHz and 2.480 GHz, and in particular the Bluetooth standard, be transferable with the data transmission means. Bluetooth is an industry standard for wireless radio networking of devices over short distances. This provides a wireless interface through which, in particular, mobile devices can communicate with each other. This cable connections between the devices are replaced. Bluetooth devices generally transmit in the license-free ISM band (Industrial, Scientific and Medical Band) and may be operated worldwide without authorization.

In a further embodiment of the device according to the invention, the evaluation unit has a memory for measurement data. This memory can be realized additionally or alternatively to a corresponding memory in the measuring means of a gas pressure spring according to the invention.

In a particularly preferred manner, the evaluation unit has a programmable logic controller (PLC). The PLC can first evaluate the transmitted measured value data. If deviations from a specified target value are detected, the PLC can act directly on the machine or tool that contains the monitored gas springs. For example, the stroke or the frequency of the machine can be precisely monitored and adjusted. Since a feedback of measured value data influences a manipulated variable, there is a control behavior of the PLC. Alternatively, the PLC can also perform simple control tasks of the machine or of the tool without feedback of measured value variables taking place.

The programmable logic controller (PLC) may be formed integrally with the evaluation unit or separately from the evaluation unit.

If the programmable logic controller (PLC) forms a separate component of the device according to the invention, it is preferred that between the evaluation unit and the programmable logic controller (PLC) for data exchange one or more of the bus systems ASInterface bus, PROFIBUS, PROFINET, Interbus, Interbus-Safety, CAN and CANopen is set up.

The mentioned bus systems allow a fast and large-volume data exchange, without incurring an increased cabling effort.

In general, a development of the device is particularly favored, in which several gas springs are connected on the pressure side. In this case, the common pressure value of several gas springs can be determined with only one sensor (measuring means). Thus, both the investment and the wiring and the associated space requirements are reduced.

• – Aufnahme des Werts einer physikalischen Messgröße innerhalb und/oder an der Gasdruckfeder mit einem Messmittel,
• – Übertragung der Messwertdaten an eine Auswerteeinheit, und
• – Auswertung der Messwertdaten in der Auswerteeinheit.

The device according to the invention can be used in the following way:

• Recording the value of a physical measured variable inside and / or on the gas spring with a measuring device,
• - Transmission of measured value data to an evaluation unit, and
• - Evaluation of the measured value data in the evaluation unit.

In this case, one or more values of the pressure and / or the temperature can be recorded. The device is designed such that measured value data can be stored in the measuring device and / or in the evaluation unit. In a further refinement, the measured value data is transmitted from the measuring device to the evaluation unit with one or more conductors, in particular cables, and / or with one or more coupled conductor tracks (bus). In this case, the Profibus and / or the CANopen protocol can be used, with measurement data being optionally stored in a CAN data logger.

In a particularly preferred development of the device, the latter can transmit the measured value data from the measuring device to the evaluation unit by radio, in particular with short-range GHz radio waves, in particular with radio waves in the ISM band between 2.402 GHz and 2.480 GHz, and in particular according to the Bluetooth standard.

Furthermore, it is particularly preferred to use a programmable logic controller (PLC) for monitoring the measured values and, if appropriate, for controlling individual gas pressure springs and / or the entire tool or the entire machine.

If the programmable logic controller (PLC) is separate from the evaluation unit, one or more of the protocols AS-Interface bus, POFIBUS, PROFINET, Interbus, Interbus-Safety, CAN and CANopen are preferably used for data exchange between these devices.

In a particularly preferred embodiment, finally, the number of completed strokes on the change in the measured pressure within one or more gas springs - detected and stored - in particular by the evaluation. This is made possible by the inventive method, in a particularly simple and tamper-proof manner to determine the number of total strokes performed a machine or a tool and hold. This is particularly interesting for leasing or rental machines.

In this case, the length of the lifting movement and the frequency of a machine or a tool can be determined via the measured value data of the gas pressure springs used.

There are now various possibilities for designing and developing the teaching of the present invention in an advantageous manner. For this purpose, on the one hand to refer to the subordinate claims and on the other hand to the following explanation of three preferred embodiments of the device according to the invention. In conjunction with the explanation of the preferred embodiments of the device based on the. Drawing also generally preferred embodiments and developments of the gas spring according to the invention and the method of the invention are explained. In the drawing show:

1 a schematically illustrated circuit diagram of a first embodiment of the device according to the invention, in which a plurality of gas springs are connected to an evaluation unit designed as a programmable logic controller (PLC), wherein the PLC has a CAN interface,

2 a second embodiment of the device according to the invention, in which a CAN data logger is provided, and

3 a circuit diagram of a third, particularly preferred embodiment of the device according to the invention, in which measured value data are transmitted by radio.

1 shows a schematically illustrated circuit diagram of a first preferred embodiment of the device according to the invention. A plurality of gas springs 1 are arranged in a machine to accommodate strokes and cushion these and / or dampen. Every gas spring 1 is with at least one measuring means for monitoring at least one in or on the gas spring 1 equipped physical measured variable equipped. These measuring devices are not shown here in detail.

Here, every gas spring shows 1 at least one pressure or temperature sensor or a combined pressure / temperature sensor. A gas spring 1 can distributed over the length also have a plurality of pressure sensors, for example. For measuring the pressure of a compressed gas in front of and behind the piston. Furthermore, a plurality of temperature sensors may be provided, for example within the gas spring for measuring the temperature of the gas and on the surface of the gas spring. The pressure medium is nitrogen in the present case.

For evaluation and further processing of the measured value data is outside the range in which the gas springs 1 are arranged, an evaluation 2 intended. In the present embodiment, the evaluation unit 2 as programmable logic controller (PLC) 3 educated.

For transmission of the measured value data of the individual measuring means to the evaluation unit 2 are data transmission means 4 intended. This data transmission means 4 are in the present example as a bus 5 and specially designed as a CAN bus. The evaluation unit has to process the measured data 2 accordingly via a CAN interface 6 ,

Since the programmable logic controller (PLC) 3 via the CAN interface 6 has, the storage and evaluation of the measured data in the evaluation unit formed thereby 2 occur.

2 shows a circuit diagram of a second embodiment of the device according to the invention, which to the embodiment of 1 is ajar. Here, however, is on the bus 5 between the gas springs 1 and programmable logic controller (PLC) 3 a CANDatenlogger 7 , Consequently, the CAN data logger works in this embodiment 7 as an evaluation unit 2 , The CAN datalogger 7 is configured to store measurement data on an SD memory card and only error information to the PLC 3 passes. As a result, an independent monitoring is realized. Furthermore, it is possible with the recorded measured value history to determine and reproduce measured value tendencies. The CAN datalogger 7 is caused by a voltage source 8th supplied with electrical energy.

3 shows a schematic diagram of a third, particularly preferred embodiment of the device according to the invention. Here, the data transmission means are designed such that measured value data from the gas pressure springs 1 to the evaluation unit 2 via radio waves 9 are transferable. The radio waves 9 are indicated in this illustration, details in the field of measuring means of the gas springs 1 arranged data transmission means are not visible here. The data transmission means communicate with an evaluation unit 2 here as a radio receiver 10 is trained. The evaluation unit 2 has an integrated microcontroller. Between the gas springs 1 and the radio receiver 10 measured value data are transmitted in the short-range GHz radio wave range, preferably according to the Bluetooth standard. The evaluation unit 2 furthermore has a memory for measured data. It is powered by a voltage source 8th supplied with electrical energy.

Separated from the evaluation unit 2 is also a PLC here 3 intended. With the PLC 3 various control tasks can be fulfilled, in particular concerning the device in which the gas pressure springs 1 are arranged. Unless the gas springs 1 are also adjustable in terms of their suspension / damping behavior, the PLC 3 also act in a corresponding manner.

For communication between the evaluation unit 2 and the PLC 3 is a bus 5 intended. Again, it may be a CAN, a CANopen bus or any other known protocol.

In all embodiments shown, the measuring means of the gas pressure springs 1 a network-independent power supply. This achieves the greatest possible independence.

With regard to further advantageous embodiments of the gas spring according to the invention, the device is made to avoid repetition of the general part of the description and to the general part of the specification and the claims.

Finally, it should be expressly understood that the above-described embodiments of the device according to the invention are only for the purpose of discussion of the claimed teaching, but do not limit these to the embodiments.

LIST OF REFERENCE NUMBERS

1

Gas spring

2

evaluation

3

Programmable logic controller (PLC)

4

Data transmission means

5

bus

6

CAN interface

7

CAN data logger

8th

voltage source

9

radio waves

10

radio receiver

Claims (14)

Gas spring ( 1 ), in particular for receiving strokes in a tool or in a machine, wherein one or more measuring means for monitoring at least one inside and / or on the gas spring ( 1 ) occurring physical measured variable and wherein the measuring means comprise a pressure sensor or a combined pressure / temperature sensor and / or a temperature sensor, characterized in that the measuring means have a mains-independent power supply. Gas spring ( 1 ) according to claim 1, characterized in that the measuring means comprise a memory for measurement data. Device for monitoring at least one inside and / or on a gas spring ( 1 ) occurring physical measure, wherein the device comprises: - one or more gas springs ( 1 ) according to one of claims 1 or 2, - one or more evaluation units ( 2 ), and - one or more data transfer means ( 4 ) for the transmission of data between the measuring device and the evaluation unit ( 2 ). Device according to claim 3, characterized in that the evaluation unit ( 2 ) has a microcontroller. Device according to Claim 3 or 4, characterized in that the data transmission means ( 4 ) one or more conductors, in particular cables, and / or one or more coupled interconnects (bus) ( 5 ) exhibit. Device according to Claim 5, characterized in that the data transmission means ( 4 ) a bus ( 5 ) according to the CANopen protocol and / or the Profibus protocol. Device according to Claim 6, characterized in that a CAN data logger ( 7 ) is provided with the measurement data can be stored. Device according to one of claims 3 to 7, characterized in that with the data transmission means ( 4 ) Data with radio waves ( 9 ) are transferable. Device according to claim 8, characterized in that with the data transmission means data in the short-range GHz radio wave range, in particular in the ISM band between 2.402 GHz and 2.480 GHz, and in particular according to the Bluetooth standard, are transferable. Device according to one of claims 3 to 9, characterized in that the evaluation unit ( 2 ) has a memory for measurement data. Device according to one of claims 3 to 10, characterized in that the evaluation unit ( 2 ) a programmable logic controller (PLC) ( 3 ) having. Device according to one of claims 3 to 10, characterized in that separated from the evaluation unit ( 2 ) a programmable logic controller (PLC) ( 3 ) is provided. Device according to claim 12, characterized in that between the evaluation unit ( 2 ) and the programmable logic controller (PLC) ( 3 ) is set up for data exchange of one or more of the bus systems AS-Interface bus, POFIBUS, PROFINET, Interbus, Interbus-Safety, CAN and CANopen. Device according to one of claims 3 to 13, characterized in that a plurality of gas pressure springs ( 1 ) are connected on the pressure side.

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