EP2171415A2

EP2171415A2 - Gas pressure spring with measurement means and device and method for monitoring at least one physical measurement variable which occurs inside and/or at a gas pressure spring

Info

Publication number: EP2171415A2
Application number: EP08758132A
Authority: EP
Inventors: Norbert Reinmuth
Original assignee: Fibro GmbH
Current assignee: Fibro GmbH
Priority date: 2007-07-20
Filing date: 2008-05-30
Publication date: 2010-04-07
Also published as: WO2009012737A2; DE102007034416A1; US20100138172A1; WO2009012737A3

Abstract

A gas pressure spring (1), in particular for absorbing stroke movements in a tool or in a machine, is designed and developed, with respect to the replicability and predictability of the behavior during use, as a function of the respective use conditions such that one or more measurement means for monitoring at least one physical measurement variable which occurs inside and/or at the gas pressure spring are provided. Furthermore, a device and a method for monitoring at least one physical measurement variable which occurs inside and/or at a gas pressure spring (1) are proposed.

Description

GAS PRESSURE SPRING WITH MEASURING INSTRUMENT AND EQUIPMENT

AND METHOD FOR MONITORING AT LEAST

ONE INSIDE AND / OR ON A GAS PRESSURE SPRING

OCCURRING PHYSICAL SURVEY

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 and a method 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 hydro-pneumatic 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 found, for example, in office chairs or as holding devices 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 observed in the respective operating situation use behavior, ie in particular the damping and suspension characteristics of the gas spring, for example, 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 detect both the temperature of the surface of the gas spring and the temperature of the compressed gas within the spring. the lose weight. 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.

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 operating conditions.

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 a solution that is as economical as possible, the data transmission means 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, i. from bus systems.

Such a bus system can operate according to the CANopen protocol and / or the PROFI BUS 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. There are in other words, data transmission means are provided which forward the measured value data from the measuring means of the gas pressure springs to the evaluation unit by radio. 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 regard to the aforementioned embodiment, it is preferred that 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, 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, via which mobile devices in particular 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 provide simple control perform tasks of the machine or the tool, without the feedback of measured value sizes 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 AS-Interface 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.

The above object is finally achieved with respect to a method for monitoring at least one occurring within and / or on a gas spring physical quantity with the features of claim 18. Thereafter, a method according to the invention comprises the following steps:

Recording of the value of a physical measured quantity inside and / or on the gas pressure spring with a measuring device, transmission of the measured value data to an evaluation unit, and evaluation of the measured value data in the evaluation unit.

In accordance with the invention, a method is provided with which traceability and predictability of the operational behavior of gas springs as a function of the respective conditions of use is realized. To avoid repetition, reference is made in relation to the advantages of the method according to the invention and the preferred embodiments of the method according to the invention to the comments on the gas spring according to the invention and to the device according to the invention.

In carrying out the method according to the invention, one or more values of the pressure and / or the temperature can be recorded.

The 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 method according to the invention, measured value data are transmitted from the measuring means 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 AS-Interface bus, POFIBUS, PROFINET, Interbus, Interbus-Safety, CAN and CANopen protocols are preferably used for data exchange between these devices. In a particularly preferred development of the method according to the invention, finally, the number of strokes completed by the change of the measured pressure within one or more gas pressure springs is detected and stored, in particular by the evaluation unit. 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.

With the method according to the invention, 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. The method can therefore be used particularly advantageously for error detection, analysis and correction.

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 connection with the explanation of the preferred embodiments of the device with reference to the drawing, also generally preferred embodiments and developments of the gas spring according to the invention and the method according to the invention are explained. In the drawing show

1 is 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 formed as a programmable logic controller (PLC), wherein the PLC has a CAN interface,

Fig. 2 shows a second embodiment of the device according to the invention, in which a CAN data logger is provided, and Fig. 3 is a circuit diagram of a third, particularly preferred embodiment of the device according to the invention, are transmitted in the measured value data by radio.

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

Here, each gas spring 1 has at least one pressure or temperature sensor or a combined pressure / temperature sensor. A gas pressure spring 1 can also have a plurality of pressure sensors distributed over the length, 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, an evaluation unit 2 is provided outside the area in which the gas pressure springs 1 are arranged. In the present embodiment, the evaluation unit 2 is designed as a programmable logic controller (PLC) 3.

For transmitting the measured value data of the individual measuring means to the evaluation unit 2, data transmission means 4 are provided. These data transmission means 4 are formed in the present example as a bus 5 and in particular as a CAN bus. For processing the measurement data, the evaluation unit 2 accordingly has a CAN interface 6.

Since the programmable logic controller (PLC) 3 has the CAN interface 6, the storage and evaluation of the measured data can take place in the evaluation unit 2 formed thereby. Fig. 2 shows a circuit diagram of a second embodiment of the device according to the invention, which is based on the embodiment of Fig. 1. Here, however, located in the bus 5 between the gas springs 1 and the programmable logic controller (PLC) 3, a CAN data logger 7. Consequently, in this embodiment, the CAN data logger 7 acts as evaluation 2. The CAN data logger 7 is configured to Saves measurement data to an SD memory card and only passes error information to the PLC 3. 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 data logger 7 is supplied with electrical energy by a voltage source 8.

3 shows a schematic circuit 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 can be transmitted from the gas pressure springs 1 to the evaluation unit 2 by radio waves 9. The radio waves 9 are indicated in this illustration, but details of the data transmission means arranged in the region of the measuring means of the gas pressure springs 1 are not to be seen here. The data transmission means communicate with an evaluation unit 2, which is embodied here as a radio receiver 10. The evaluation unit 2 has an integrated microcontroller. Between the gas pressure springs 1 and the radio receiver 10, measured value data in the short-range GHz radio wave range, preferably according to the Bluetooth standard, transmitted. The evaluation unit 2 further has a memory for measurement data. It is powered by a voltage source 8 with electrical energy.

Separately from the evaluation unit 2, a PLC 3 is also provided here. With the SPS 3 various control tasks can be met, in particular concerning the device in which the gas springs 1 are arranged. If the gas springs 1 are also adjustable with respect to their suspension / damping behavior, the PLC 3 can also act in a corresponding manner. For communication between the evaluation unit 2 and the PLC 3, a bus 5 is provided. Again, it may be a CAN, a CANopen bus or any other known protocol.

In all the embodiments shown, the measuring means of the gas pressure springs 1 have 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 and the method, reference is made to avoid repetition to the general part of the specification and to the general part of the specification and to 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.

Claims

claims

1. Gas pressure spring (1), in particular for receiving strokes in a tool or in a machine, g ekecked one or more measuring means for monitoring at least one within and / or on the gas spring (1) occurring physical quantity.

2. Gas spring (1) according to claim 1, characterized in that the measuring means comprise a pressure sensor or a combined pressure / temperature sensor.

3. Gas spring (1) according to claim 1 or 2, characterized in that the measuring means comprise a temperature sensor.

4. Gas spring (1) according to one of claims 1 to 3, characterized in that the measuring means have a mains-independent power supply.

5. Gas pressure spring (1) according to one of claims 1 to 4, characterized in that the measuring means have a memory for measurement data.

6. Device for monitoring at least one inside and / or on a gas spring (1) occurring physical measured variable, wherein the device comprises: one or more gas springs (1) according to one of claims 1 to 5, one or more evaluation units (2), and one or more data transmission means (4) for transmitting data between the measuring means and the evaluation unit (2).

7. Device according to claim 6, characterized in that the evaluation unit (2) has a microcontroller.

8. Device according to claim 6 or 7, characterized in that the data transmission means (4) one or more conductors, in particular cables, and / or one or more coupled conductor tracks (bus) (5).

9. Device according to claim 8, characterized in that the data transmission means (4) have a bus (5) according to the CANopen protocol and / or according to the Profibus protocol.

10. Device according to claim 9, characterized in that a CAN data logger (7) is provided, with the measurement data can be stored.

11. Device according to one of claims 6 to 10, characterized in that with the data transmission means (4) data with radio waves (9) are transferable.

12. The device according to claim 11, characterized in that 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.

13. Device according to one of claims 6 to 12, characterized in that the evaluation unit (2) has a memory for measurement data.

14. Device according to one of claims 6 to 13, characterized in that the evaluation unit (2) has a programmable logic controller (PLC) (3).

15. Device according to one of claims 6 to 13, characterized in that separate from the evaluation unit (2) has a programmable logic controller. (PLC) (3) is provided.

16. Device according to claim 15, characterized in that between the evaluation unit (2) and the programmable logic controller (PLC) (3) for Data exchange of one or more of the bus systems AS-Interface bus, POFIBUS, PROFINET, Interbus, Interbus-Safety, CAN and CANopen is set up.

17. Device according to one of claims 6 to 16, characterized in that a plurality of gas pressure springs (1) are connected on the pressure side.

18. Method for monitoring at least one physical measured variable occurring inside and / or on a gas pressure spring (1), the method comprising the steps:

Recording of the value of a physical measured quantity inside and / or on the gas pressure spring (1) with a measuring device, transmission of the measured value data to an evaluation unit (2), and evaluation of the measured value data in the evaluation unit (2).

19. The method according to claim 18, characterized in that one or more values of the pressure and / or the temperature are recorded.

20. The method according to claim 18 or 19, characterized in that measured value data in the measuring means and / or in the evaluation unit (2) are stored.

21. The method according to any one of claims 18 to 20, characterized in that measured value data from the measuring means to the evaluation unit (2) with one or more conductors, in particular cables, and / or with one or more coupled tracks (bus) (5) are transmitted.

22. The method according to claim 21, characterized in that the Profibus and / or the CANopen protocol is used, wherein optionally measurement data in a CAN data logger (7) are stored.

23. The method according to any one of claims 18 to 22, characterized in that measured value data from the measuring means to the evaluation unit (2) by radio, in particular with short-range GHz radio waves, in particular with radio waves (9) in the ISM band between 2.402 GHz and 2.480 GHz, and in particular according to the Bluetooth standard.

24. The method according to any one of claims 18 to 23, characterized in that a programmable logic controller (PLC) (3) is used to monitor the measured values and possibly for control.

25. The method according to any one of claims 18 to 24, characterized in that for data exchange between the evaluation unit (2) and the programmable logic controller (PLC) (3) one or more of the protocols AS-Interface Bus, POFIBUS, PROFINET, Interbus, Interbus-Safety, CAN and CANopen is used.

26. The method according to any one of claims 18 to 25, characterized in that the number of completed strokes on the change of the measured pressure within the gas spring (1) - in particular by the evaluation unit (2) - detected and stored.