DE202014000334U1 - Support force measuring device with induction coupling - Google Patents

Abstract

Support force measuring device for measuring a support force on a support element of a support structure of a particularly mobile work machine, with at least one measuring element that is connected to a deformation body that is deformable under the action of the support force to form a sensor and emits a signal proportional to the support force, a support foot that contains the sensor and with the support element is movably connected, wherein the support element contains an electrical cable connection which is set up for the transmission of electrical energy and for the transmission of the signal proportional to the support force to an evaluation device in the machine, characterized in that the support element and the sensor in the support foot have an electromagnetic interface , by means of which the measuring element is supplied with electrical energy from the machine via electromagnetic induction and the signal proportional to the supporting force from the measuring element by means of electromagnetic inductance ion is transmitted to the cable connection of the support element.

Description

The invention relates to a measuring system with a force transducer for detecting supporting forces in a support structure, in particular of supporting forces in a support element which forms part of a support structure. The support structure is used in statically mounted cranes, supported work machines, mobile crane vehicles, mobile hoists, drills, self-propelled guns or the like, which are referred to below as a working machine or machine. In 1 is a crane vehicle 1 schematically shown, which serves to secure the state and during operation on supporting elements 2 stands, which are also called support feet. The support elements 2 are located in the end of extendable arms 3 attached to a frame 44 are fastened to the vehicle. Each of the outriggers 3 can be designed as a telescopic boom, which is out of the frame 44 can be spent with or without power assistance by means of a linear movement in its laterally protruding from the vehicle operating position. It is also possible the boom 3 pivotable, so the boom 3 , If necessary, with external power assistance, can be moved by a pivoting movement about a vertical or about a horizontal axis in the operating position projecting laterally from the vehicle. The end portion of the boom can also be moved by a combined pivoting and Ausziehbewegung in the operating position. In this case, the boom is adjustable in length (extendible) and is pivotally mounted at one end to the vehicle. In a further embodiment of the boom can also have multiple hinged joints, so that the boom can fold out with a folding movement in the operating position. The pull-out movement, the swiveling out movement as well as the combined movement forms should be covered here by the terms extension movement, extended movement or extension.

On site, the entire crane vehicle (generally the machine), preferably hydraulically, with the help of the support elements 2 raised, with the support elements 2 to their interpreters 3 can be extended hydraulically before. The vehicle wheels, if present, then usually do not touch the ground, but are at least relieved.

If one measures the forces transmitted vertically into the ground via the support elements, then one can determine the weight distribution and thus the center of gravity of the overall system, ie the supported machine including the load, in particular when lifting a load. These measurements allow the determination of the tipping point of the machine or crane can be used. One way to measure the support forces is to position a force transducer in the force flow of each support element. This force transducer then outputs a signal corresponding to the respective support force, which signal is evaluated, for example, in the aforementioned manner.

The registration Liebherr, EP 2159428 shows a solution for a connection or the connection of a sensor to the crane. The solution uses a wiper connection on a central tube for signal transmission. With this solution, only a single-pole solution can be realized. So it must be the vehicle mass of the crane used as a second pole. However, this can lead to current drains and faults in damp ground or rain; therefore, the signal may be faulty in that respect. Furthermore, there is basically the risk of interruption of the connection within the cylinder due to open slider contacts. In addition, a single-wire connection is not suitable for common technologies which require a multi-pin connection. Thus, for safe connections such as Canbus at least five poles, but also for the 4-20 mA technology two or three-pole connections are necessary.

The object of the invention is to propose a robust support force measuring system with force sensor for a movable, extendable support element, which reliably delivers one of the load carried by the support element, the support force, corresponding signal.

This object is achieved with a support force measuring device having the features of the claims.

In a form according to the invention, a supporting force measuring device for measuring a supporting force on a movable supporting element of a supporting structure of a mobile machine in particular has at least one measuring element which is connected to a deformable deformation element under the action of the supporting force and emits a support force proportional signal, as well as at least one electrical connection for transmission of the support force-proportional signal to an evaluation device. The support element and / or the support structure have / has at least one adjustable between a rest position and an operating position section, wherein the relative position between the measuring element and the evaluation device changed. The electrical connection is a cable which is laid connecting to relatively adjustable sections of the support element or the support structure, which changes its length following an adjustment of the relative position of the sections of the support element or the support structure and which automatically returns to its original length.

By using a multi-core cable, multiple terminals of the sensor can be connected simultaneously to the evaluation device, whereby power supply and Meßwertabgriff can be done simultaneously. It is also possible to acquire several measured values at the same time, eg. B. support force and temperature. In addition, a connection through a cable is more reliable than a wiper connection, which is always subject to low wear.

Preferably, the adjustable portion is connected to a hydraulic piston / cylinder assembly and the cable is arranged across the cylinder space of the piston / cylinder assembly.

Preferably, the cable is electrically and mechanically firmly connected on the one hand with a fluid-tight current feedthrough through the wall of the cylinder and on the other hand with a fluid-tight current feedthrough through the piston.

Preferably, the cable is guided in a multi-part, telescoping protective tube, wherein a respective end-side segment of the telescoping protective tube is connected to the piston or to the cylinder bottom.

Preferably, the cable has an initial shape, in which it returns automatically following a decreasing expansion, wherein the initial shape is helical, helical, bellows-shaped zigzag or loop-shaped or has a combination of these basic shapes. For example, this required elasticity can be achieved by appropriate design of the cable sheath, the cable itself or by the use of appropriately preformed foil cable.

Preferably, the initial shape of the cable, in particular a helical output shape of the cable, is adapted to conform to the inner diameter of the cylinder to guide the cable.

Also preferably, the cable is wound on an automatic retractor, which rolls up the cable under spring force and preferably in the middle section on both sides.

Preferably, the cable is multi-core. In this way, different signals can be transmitted simultaneously for evaluation, these can be in addition to the Stützkraftmesssignalen temperature measuring signals or the like.

Preferably, the support structure horizontally extendable boom and / or attached to the boom end, hydraulically vertically adjustable support elements, wherein the deformation body is attached to the measuring element on the boom and / or on the support element. Particularly preferably, the support element has a hydraulic cylinder with a piston rod, wherein the deformation body forms a portion of the piston rod.

Alternatively or additionally, the support element has a support foot for resting on the floor, wherein the deformation body is mounted in a connecting portion between the piston rod and the support leg, or forms this. Preferably, the connecting portion is a ball joint and the deformation body is a part of the ball joint.

Preferably, the shape of the deformation body is chosen such that it is deformable in the direction of support force and stiff in the transverse direction.

Preferably, the evaluation device can detect the extension length of the boom and calculate with the associated measured value for the supporting force to determine the center of gravity of the machine.

In addition, the cantilevers may be supported in the extended position by force gauges that sense machine-side loads on the cantilevers.

Preferably, the boom by means of one or more piston / cylinder arrangements are hydraulically adjustable and the cable arranged this piston / cylinder assemblies by cross.

In a further form according to the invention, a supporting force measuring device for measuring a supporting force on a supporting element of a supporting structure of a mobile machine in particular has at least one measuring element which is connected to a deformable deformation element under the action of the supporting force to form a sensor and emits a support force proportional signal, as well as a supporting foot. which contains the sensor and is movably connected to the support element. The support element contains an electrical cable connection which is set up for the passage of electrical energy and for the transmission of the support force-proportional signal to an evaluation device in the machine. The support element and the sensor in the support leg have an electromagnetic interface, by means of which the measuring element is supplied via electromagnetic induction with electrical energy from the machine and the support force proportional signal is transmitted from the measuring element by means of electromagnetic induction to the cable connection of the support element.

In this arrangement, an interface is used in addition to a reliable cable connection, which is resistant to corrosion and moisture and also the replacement of the sensor or the support foot z. B. on the site itself.

Preferably, the measuring element is connected to a circuit containing a rechargeable buffer memory for storing electrical energy, which is used for the supporting force measurement and the transmission of the support force proportional signal.

Preferably, the evaluation device is adapted in the machine to switch over time between a charging operation for charging the buffer memory and a measuring operation for measuring the supporting force with transmission of propped force proportional signal, the switching cycle time-controlled or by the state of charge of the buffer memory or the size of a measured value for the supporting force is dependent.

Alternatively and also preferably, the transmission of energy and the transmission of the support force proportional signal can be carried out at the same time by a modulated AC voltage is transmitted as a carrier wave for the signal via the electromagnetic interface.

Preferably, the sensor is replaceable installed in the support leg. This makes it possible, without disconnection or reconnection to replace the sensor during maintenance or adapt to adapt the measurement task, for example, to another measuring range or the addition of temperature measurement.

Preferably, the support leg has a ball socket, which is supported on the sensor, wherein the support element has a ball joint, which is received in the ball socket. The stützfußseitige part of the electromagnetic interface can be recessed in a recess in the ball socket and the support member side of the electromagnetic interface can be recessed in a recess in the ball joint, so that these two parts face each other without contact.

Further advantageous embodiments of the support force measuring device, have been set out above and it is hereby expressly made to these statements.

In a further form according to the invention, a supporting force measuring device for measuring a supporting force on a supporting element of a supporting structure of a mobile machine in particular has at least one measuring element which is connected to a deformable deformation element under the action of the supporting force to form a sensor and emits a support force proportional signal, and a supporting foot, which contains the sensor and is movably connected to the support element. The support leg has an electrical energy store and a radio transmitter connected to the sensor and configured to wirelessly transmit a sensor signal proportional to outreach power to a radio receiver in the machine.

In this form of the invention, a multi-channel possibly expandable system can be used which reports measured values for supporting forces, temperatures, states of charge or functional impairments etc. to the evaluation device. The system is very easy to retrofit, since only a constant power supply in the control room of the machine is required, which is usually already available.

Preferably, the electric energy storage is a rechargeable storage, and the support foot is provided with a charging means by means of which the storage can be charged. Solutions are conceivable in which non-rechargeable memory can be used; As a rule, the operating times are too long to send measuring signals at a reasonable frequency with the use of non-rechargeable current stores at a reasonable cost and with the protection of the environment.

Preferably, the radio receiver is connected in the machine with an evaluation device, which converts the support force proportional signal into a vertical load.

Preferably, the radio transmitter and the radio receiver are each configured as a radio transmitter and receiver and configured to communicate with each other. Preferably, the radio transmitters and receivers for data transmission by means of radio waves are arranged to couple with each other according to a predetermined protocol and to verify the signal origin and correct transmission at the receiver of the machine.

Preferably, the storage for electrical energy is connected to a charging device having a charging socket for connecting a power source or a non-contact, electrical energy by electromagnetic induction transmitting interface. The latter embodiment can operate in a short-circuit-free manner, especially in the dirty environment of construction sites, because no electrical contacts are exposed.

Preferably, the support leg has a device for monitoring the state of charge of Memory for electrical energy, which is set up, transmitted via the radio transmitter data on the state of charge to the radio receiver of the machine.

The support leg preferably has an antenna of the radio transmitter, which is arranged in a recess and preferably potted with plastic.

Preferably, the support foot carries on its upper side lighting means, preferably LEDs, which are controlled by the radio transmitter to indicate operating conditions by light signals. The light signals can be distinguishable by light color or light intervals, in particular continuous light and flashing with different frequencies, and preferably indicate different operating states such as in particular readiness for operation, malfunction, interruption of the radio contact, state of charge of the memory.

This embodiment has the advantage that in particular warnings of dangerous operating conditions of the work machine both the operator and the other people who do not necessarily have insight into the cab, also can be warned.

The radio receiver is preferably mounted in a control station of the machine operator and has a screen on which the measured values and / or values calculated from the measured values, in particular the permissible extension length and the angular value of a crane jib, are displayed in a mobile crane.

In particular, the lighting means as well as the described functions can be expressly applied to the other forms of the invention. Attention to the invention should also be devoted to the problem of transverse forces; that as follows from the 2 is shown

When lifting the vehicle with the support elements and when lifting a load vehicle frames deform 44 , Boom 3 and support elements 2 such that the ends or support feet of the support elements 2 who are standing on the ground, want to move away from each other in the horizontal direction d, as in 2 is shown. However, this movement is partially prevented by the fact that the coefficient of friction between the ground and support foot 2 not zero. As a result, horizontal reaction forces build up between the support elements, which generate bending moments in all components that are traversed by the flow of force.

A metrological problem is that each real force transducer or sensor reacts not only in the direction of the force for which it is designed, but more or less also on forces and moments in all other directions that affect it. In order to detect, for example, the center of gravity of the vehicle supported by the support elements or crane, but only the vertical forces, the supporting forces are relevant.

The horizontal forces occurring in the application described above, in particular those on the individual support elements, amount to a metrologically relevant interference component of the vertical forces to be measured.

It is difficult to find a suitable mounting location for a load cell on the vehicle or crane. The conditions of use are often harsh around a crane or a crane vehicle.

Cable connections and sensor are exposed to contamination. Furthermore, the support elements in the extended state are also exposed to mechanical stresses and potential collisions by the operation of machines and vehicles and heavy equipment in the immediate vicinity. However, safety and working capacity should not be restricted or impaired.

The invention provides a solution to the difficulties mentioned.

With the invention of the force transducer is integrated into the support so that it is robustly integrated into the structure, and at the same time provides a safe signal.

Thus, in one form of the invention, it is designed so that it is easy to mount on the end of the support, experiences little influence by lateral forces and moments and can withstand the environmental influences such as moisture and dirt well.

But it can also be integrated at another point in the power flow of a supporting element, such. B. also at any point of the piston rod.

Since the application described here is usually a safety-relevant application, it is also important that the metrological properties of the force transducer remain the same over a long period of time and that the minimum requirements for functional safety are met.

Furthermore, such equipped with support feet vehicles are usually in the open in use. There may, for example, a vehicle side in the sun, so that the support feet are heated on this side, while the other support legs are in the shade. This can help result in significant temperature differences that can distort the measured deformations or strains, in particular the measured resistance values (ie forces) in the force transducer. Advantageously, the force transducer may include additional temperature measurements, it may, for example, wear temperature-sensitive resistors that allow temperature compensation directly on the load cell. It is particularly advantageous if the sensor carrying the load-measuring resistors also has the temperature-measuring resistances directly next to it.

There are a variety of vehicles with attachments that require the use of support feet. Consequently, also different maximum load loads on the support feet are to be expected and recorded. In order to allow an accurate measurement over the respective rated load range, the force transducer should be designed so that it can output a signal that changes evenly throughout the rated load range. For this it is advantageous if the sensor can be replaced without the production of electrically conductive connections.

In addition, in order to avoid the storage of a plurality of different sensors, which are each adapted for a rated load range, it is advantageous if a single standard measuring element is used and the deformation body of the sensor in its geometry of the measuring task, d. H. is adapted or adapted to the nominal load range.

This adaptation over the shape of the deformation body is very easy to calculate and also to manufacture, since preferably the diameter of a rotating part (cylinder diameter) are adjusted, which is easy and accurate to implement in practice.

In a further embodiment of the invention, the adaptation to different loads is designed such that over a standard deformation body different sleeves are placed, which then deform less by increasing the cross-sections and thus can dissolve higher loads. In a further embodiment of the invention, it is conceivable to integrate a force sensor in the horizontal support structure of a cantilever in order to improve the accuracy of the measurement result. For this purpose, the sensor in the form of a measuring element connected to a deformation body and z. B. be incorporated by welding or interference fit in the support structure to measure the supporting force.

This embodiment can be realized by a reinforcing structure, which is additionally applied to the support structure and connected thereto, so that the sensor is received as an integrated element.

The advantage here is that the entire gain can be measured as an assembly and tested before it is attached to the support elements.

For this purpose, it is advantageous if the reinforcing structure has been weakened in a defined manner around the force transducer in order to allow a location of maximum and defined strains for dissolution, measurement of the loads or force flows at the measuring location.

The adaptation to different loads is then designed, for example, such that then the additional structure is executed differently strong, or the defined weakenings are performed differently.

In a further embodiment of the invention, the force sensor is integrated in the lowermost support plate, the support leg of a support element below a ball joint. For this purpose, the sensor is placed below a ball seat, which is interchangeable.

Various inserts with different ball diameters can be quickly adapted to the respective crane vehicle.

The sensor may be a force sensor which absorbs expansions, that is to say changes in length, on a deformation body. This may be a strain gauge which measures strains or a coupled membrane which expands, bulges or deforms under the influence of force. Here also optical methods, especially with fiber can be used which can measure strains. In general, various approaches are possible here. Another method for detecting supporting forces could be a hydraulic measuring element, which measures a pressure of an enclosed piston chamber as pressure and outputs converted into force. Even if these measured data are transmitted by radio, the power supply can be realized by a 1 or 2 pole connection on the vehicle using the vehicle ground as the second pole.

The sensor can also be realized as a movable force measuring axis, which evaluates the acting support forces of the extendable boom of the mobile machine depending on the extended state or extended length or width and angle. In this case, for example, the resulting bending of the axle or bearing forces, axle forces at the bearing of the axle is evaluated.

The force sensor can also be a SAW sensor or a sensor with RFID functionality, which is excited as a resonant circuit via waves and then independently emits a resonance response. For this purpose, it may be necessary for each support leg to include a coded address to prevent confusion of the measured values. Of the

In this case, the force sensor can preferably be interrogated via a wireless, for example, inductive connection through the support foot and its ball joint.

For this purpose, suitable transmitting and receiving means are integrated in the ball and in the pickup plate of the support leg, which accomplish the transmission of measured values or the transmission of energy for the operation of the sensor.

In a further embodiment of the invention, each of the force sensors communicates with an evaluation device by means of transceivers installed on its side of the machine, which transmit a proper transmission of the data by mutual transmission and retransmission in conjunction with a test algorithm.

Particularly advantageous is a two-wire design by the support leg to the monitoring (evaluation device) of the crane (the machine), which takes over the power supply, and at the same time the measurement signals analog or digital aufgetaktet to a supply voltage or supply current, modulated.

Optionally, the connection is designed as a five-pole CAN bus, or implemented via radio over several channels.

In a transmission by radio in particular the display in the crane cab on a slewing crane is easy to retrofit, because wiper contacts are not needed. Only one power supply is needed, and an evaluation with receiving unit and display can be simply retrofitted within sight of the crane operator, placed.

Lights on the evaluation or on each support plate can visually confirm a correct connection and installation on site indicate.

For ease of handling and assembly of the sensor system, the foot plate is closed from above with a bolt-on closing part, or is open at the top and is simply locked, and is otherwise secured to the vehicle during transport in a loading and transport device.

In one embodiment of the invention, the force sensor is integrated in the piston rod of the support foot.

The invention will be described in more detail below with reference to the schematic drawing. In the drawings shows:

1 one of support elements on a crane truck in front view;

2A a boom with schematically occurring deformations and a reinforcing structure;

2 B a boom which is swingable about a vertical axis from the vehicle;

2C a boom which is swingable about a horizontal axis of the vehicle;

3 a hydraulically extendable boom with sensor and a support foot with sensor on the lower foot;

4 various electrical couplings for a sensor by a support foot;

5 a sectional view of a support leg with sensor element and sleeves for adaptation to maximum loads and an enlargement 5A the sensor body;

6A - 6B a support foot with sensor inserts for different ball joints;

6C a support foot with wireless connection to the crane control;

6D a support foot with radio connection to the crane control;

7 a schematic sectional view of a support leg with a sensor in the piston rod of a hydraulic cylinder;

8th a crane truck with mountable support feet, which send a measured value to the crane cabin by radio; and

9 a solution in which a force sensor is formed from a piston / cylinder arrangement with a pressure measuring device.

According to 1 has a rotating crane 1 , which is a machine in the sense of this application, a base frame or base 44 , on the horizontal sliding beams or outriggers 3 are attached. At the outriggers 3 are support feet 2 mounted, which can lift the crane structure or the entire vehicle defined.

Depending on the attached load 5 , extended length of crane jib, mast 8B , attached extensions 8C , Self weight of the crane and placement of balance weights 8A , as well as extended length L of the boom 3 with the support feet 2 results in a maximum load for lifting a load 5 before the crane threatens to topple.

The approach to or the achievement of this maximum load, also referred to as overload limit, can be displayed to the crane operator by evaluating the support forces of all support elements.

For this purpose, sensors are provided in the support structure.

According to 2A a force sensor within the support structure at different points attachable. For example, in the support element, support foot 2 in the sphere of the sphere 4 , on the boom 3 on a reinforcing element 5 , or in the carrying-roll axle 7 a jib 3 , The invention is applicable to these applications, preferably to the applications where sensor and evaluation are movable relative to one another.

In 2 B is shown a solution in which the boom 3 can be pivoted about a vertical axis from the vehicle. journal 7 to the the boom 3 pivots can be designed as force measuring axes. In addition, other force sensors, as described below, in the sphere 4 of the support foot 2 or in the support plate 9 provided and connected in the manner described with the evaluation device of the crane.

In 2C is shown a solution in which the boom 3 about a horizontal axis driven by a hydraulic cylinder 300 , can be swung out of the vehicle. pivot points 7 to the the boom 3 and the hydraulic cylinder pivot, can be designed as force measuring axes. In addition, other force sensors, as described below, in the sphere 4 of the support foot 2 or in the support plate 9 provided and connected in the manner described with the evaluation device of the crane.

In 3 Two sensors are shown which are redundant to each other on a support structure 6 with boom 3 and support foot 2 operable, thus further enhancing the safety of the crane.

The support structure 6 consists essentially of a horizontal boom 3 and a vertical support leg 2 , A crane vehicle, as is in 1 is shown, usually has two such arrangements on both sides of the vehicle, so a total of four support legs 2 to four outliers 3 ,

In the following, only one such support structure will be described; the duplication is done by attaching identical or mirror-image designed support structures to the remaining vehicle points.

A first force sensor 10 is at the foot above the ball joint 4 attached, which is a support plate 9 receives. The support foot 2 is in two parts as a hollow cylinder with retractable piston 11 manufactured. By introducing a hydraulic oil 13 under pressure P2 becomes the piston rod 11 extended until the support plate 9 Contact with the underground 12 gets and the crane is lifted.

The force sensor 10 This is for example via a spiral cable 14 contacted, which is performed by the piston-cylinder unit, preferably in the middle. About a sealing contact 15 the measuring signal is then directed to the crane control or crane monitoring.

It is also possible that the boom 3 hydraulically via a piston-cylinder unit 16 which is movable within the jib 3 is stored, the relative to the crane substructure not shown here on rollers 7 or plain bearing plates 7B can be extended or retracted.

The boom sensor 17 is then preferably as part of a plate 5 on the boom 3 For example, attached by welding. recesses 18 around the boom sensor 17 concentrate the flow of force around or on the cantilever sensor and improve the measurement signal.

Analogous to the versions for the support foot 2 , can a cable 14B of the cantilever sensor 17 be guided by the hydraulic oil and by the piston-cylinder unit for crane control. It is also possible that the cable 14B with the cable 14 of the support foot 2 is electrically connected, so the cable 14B the measured values of the force sensor 10 as well as the cantilever sensor 17 for evaluation (not shown) of the crane 1 leads.

According to 4 the cable can be designed differently: 4A shows a cable connection, in which the cable is formed spirally, and elastically springs back the Ummantelnde material, and is predefined in its initial shape, so that it always tries to get back to its original shape after relief from the length.

Supportive and leading acts in this case an enveloping shape such as a pipe, which is also used as a telescopic tube (not shown, s. 7 ) may be carried out, wherein in each case an end segment of the telescopic tube is fixed to the cylinder or the piston rod and a variable-length protective cover to the elastically deformable (ie, automatically returns to its original form) cable forms.

4B shows a cable connection, in which the cable is wound by means not shown in relief to a roll. This may be a spring loaded retractor.

4C shows a cable connection, in which the cable is meandering wound by means not shown.

4D shows a cable connection, in which the cable in the form of a simple (screw) spring elastically adapts to a change in length. The cable is reinforced by metallic or fibrous inserts or sheaths so that it fits its spiral shape like a spring symmetrically to the extract.

4E shows a cable connection, in which the cable is predicated accordion-shaped as a foil or ribbon conductor. For this purpose, an insulated strip conductor can also be connected as a film with a spring-elastic carrier material, for example by a laminating method with a printed circuit board material.

4F shows a cable connection, in which the cable is composed of individual elastic spring folding elements, which evert by biasing inwardly as soon as the connection is relieved.

According to 5 is the force transducer or force sensor as a section of a spherical joint or ball joint 4 formed, and consists essentially of a rust-resistant, steel deformation body, which is detected by the force to be measured caused by strained with the strain gauges strain gauges or by means of thin-film produced strain-sensitive resistors.

For this purpose, the resistors can be placed directly above the ball joint, or on a sensor body 20 be attached, which is connected to the deformation body and preferably welded thereto. When initiating the support force F on a connection plate 21 deforms the sensor zone or the sensor body 20 analogous to the load F, the resistors are deformed, and a measurement signal is evaluable for the crane control with respect to the load on this ball joint.

Here is an adaptation of the sensor and the strains occurring to the expected forces through the design of a hole 22 possible. Another adaptation of the sensor to the load of the support geometry or to a maximum load of a crane is to the connection diameter 22 of the ball and socket section different sleeves 23A . 23B in conjunction with thickness-adapted connection plates 21A . 21B to install.

By selecting sleeves and plates, the stiffness of the connection can be changed so that the amount of strain of the sensor zone can be adjusted according to the load.

To achieve a higher level of functional reliability can with respect to the interconnection on the sensor body 20 attached resistors are also two or more similar interconnected Wheatstone bridges on the sensor body whose signals are evaluated separately and evaluated in an electronic comparator circuit.

Furthermore, temperature-dependent resistors are located directly on the sensor body, with the help of which a temperature influence on the measured values can be compensated.

Will the ball joint 4 suitably designed, z. B. as in 5B is shown, one leads over the support foot in the sensor body 20 introduced horizontal force to a metrologically evaluable deformation of the sensor zone or the sensor body, if the measuring resistors 24 on a measuring diaphragm connected to the ball joint 25 are positioned, which are part of the sensor body 20 is. Consequently, the force transducer, which serves to detect the support force transmitted by the support element for carrying a load, may be designed to compensate for disturbing transverse forces. This can be achieved in particular in that the resistors are suitable (eg, cross-shaped) on the sensor body 20 to be ordered.

The load cell or force sensor has a measuring section deforming below the supporting force and transverse forces in a direction deviating from the supporting force (here measuring diaphragm 25 ) or deformation body with which it forms part of the support element. There are also several on the measuring section, the measuring diaphragm 25 , Resistors arranged firmly connected to the measuring section, which show a stretch-proportional reaction and their transverse force proportional reactions preferably cancel each other.

The extinction of the reactions can be effected by suitable arrangement of the measuring elements, in this case thin-film resistors on the measuring section and / or by corresponding processing of the measured signals.

6 (A, B, C, D) shows a foot plate 9 for a support structure of a crane, which may for example be designed as described with reference to the preceding figures.

In the embodiment according to 6 is the reception zone 30 for the ball joint 4 interchangeable designed. In particular, this sensor inserts 31 with a section-wise spherical surface 32 provided, which the supporting force of the ball joint 4 with the diameter D1 on a force sensor 33 in the support foot 9 initiate.

According to 6B are such sensor inserts 31 with securing means 34 in the support foot 9 Lockable and have a later to be described, here only analogously as a connection unit 35 represented interface via which the measurement data can be delivered to the crane control or an evaluation unit.

A first force sensor 10 is at the foot above the ball joint 4 attached, which is the support plate 9 receives.

According to 6C is a sensor insert 31 that with a force sensor 10 is operatively connected, with a connection unit 35 provided, which is designed as a radio transmitter and by radio, preferably via an antenna 37 , Sends measurement data to an evaluation unit or a crane control. The necessary energy supply can be wireless via a receiving unit 36 be supplied for example via an inductive interface.

medium 34 serve to define the sensor insert 31 in the support foot 9 , Medium 38 , here in the form of an upper ball half shell serve to fix the support foot 9 at the ball joint 4 ,

According to an embodiment according to 6D transmit such sensor inserts 31 the supporting force on double, redundant force sensors 10 , which forward their measurement data to a sensor evaluation SA. The sensor evaluation SA transmits the measured data wirelessly from a transceiver 50 to a transceiver 51 Next, which works as a receiver in the inductive interface and in the ball joint 4 is appropriate. The transceivers 50 . 51 together form an inductive interface.

In the context of this connection are coil systems 52A . 52B integrated, which also provides electrical energy to power the force sensors 10 transfer. The force sensors need not be duplicated in this embodiment, it may also be just a single force sensor 10 which is connected to a corresponding circuit SA to its measurement data via the inductive interface 50 . 51 transferred to.

The circuit SA, with the coil system 52B and the force sensor (s) 10 is connected, further includes a memory for electrical energy in the form of a rechargeable battery or a capacitor or the like. Electrical energy can be transmitted via the inductive interface 50 . 51 to transfer the force sensor (s) 10 to operate for the measurement and to reprocess the measurement signal in a suitable for the transmission to the evaluation device of the machine or in the interface 50 . 51 couple. This allows the interface 50 . 51 For example, be used alternately for energy transfer or for measured value transmission. This can be done with simple two-wire cables and / or simplified transmission forms of the signals.

Another embodiment is in 7 shown in the the support foot 2 the force sensor 10 integrated. According to 7 is the force sensor 10 within a support foot 2 integrated or mounted on the inner, upper end of the piston rod. A section of the piston rod 11 forms the deformation body to which sensors (not shown) are attached. The sensor can be used in 5A . 5B have shown shape.

The cable connection 14 is inside a telescopic protective tube 67 taken and guided, and is therefore particularly protected against damage. The pipe ensures that the cable, as the electrical signal connection, always relaxes, folds up or deposits within the pipe system and can not be pinched or pinched.

The cable to the force sensor 10 like in the 4A to 4G is shown executed.

The design after 7 can also be varied so that the force sensor 10 at a portion of the piston rod 11 is attached, which is connected to the interior of the cylinder. This arrangement has the advantage that the electrical connections to the force sensor 10 lie inside the cylinder and no electrical line must be passed through the piston.

Another embodiment is in 8th shown. A crane 1 has a boom 3 and a support leg 2 , A support plate 9 is on the support foot 2 attached and has a measuring insert 31 on, which one in the support plate 9 flush integrated antenna 37 the measured value of the support force to an evaluation unit 38 into the control cabin 40 of the crane 1 sends.

Since the measured data is transmitted wirelessly by radio, there is no further rotary electrical connection in the area, especially in the case of rotating crane structures 60 the slewing connection of the crane with the frame 44 necessary.

The radio transmission system between the support foot can in particular be designed so that the signal transmission is checked bidirectionally several times, so that the signal transmission of the transmitted signals is particularly secure.

Furthermore, by encryption, a high accuracy can be achieved, such as a Hamming distance of H = 4. Within the wireless system, each transmitting and receiving unit has a unique address, so not only always the correct reading can be assigned to the correct support foot but it can also be automatically detected by suitable means, whether the respective correct support plate 9 at the right support foot 2 is mounted.

If identical support plates are used on all support feet, then a programming function is provided with which the assignment of the support feet to the respective extension arm can be determined in the evaluation device. A corresponding safety inquiry can prevent / delay / limit the commissioning of the crane if it has not been correctly assigned. It is also possible to provide the support foot with an RFID chip as Stützfußkennung containing an identifier for the respective support foot. After attaching the support plate 9 captures the measuring insert 31 wirelessly the Stützfußkennung and logs in as a support plate of the corresponding boom at the evaluation device of the machine. The RFID chip and the means for its detection, for example, in the ball joint 4 or in the measuring insert 31 be installed as in 6D is shown.

Preferably, the entire system is composed of the Stützfußplatten 9 and in the control cabin 40 within sight of the operator mountable evaluation and warning unit 70 , which can be retrofitted, containing the evaluation device and the radio link system. In particular, the Stützfußplatten have 9 its own power supply from an energy storage, via a charging port 41 , which can also be designed as a waterproof inductive interface, is rechargeable. The evaluation and warning unit only needs on-board power, which is in the control cabin 40 usually available anyway (board socket).

Optionally have the attached measuring system or the foot plates 9 Lamp 39 which, when properly used, fitted and with secure radio transmission, visually indicate that the system is operational. The visual indication of the bulbs 39 includes light signals that are distinguishable by light color or light intervals, especially continuous light and flashing with different frequency, and preferably indicate different operating conditions such as in particular operational readiness, malfunction, interruption of the radio contact, or low charge state of the memory.

The charging ports 41 on the foot plates 9 be with a charging unit 42 connected to the crane as soon as the foot plates 9 right in a transport and cargo bay 40 the crane are mounted and / or locked. It is also possible to reload the foot plates in situ, ie in use, this can be done in particular by a portable recharging unit, which is connected to the charging port of the nachzuladenden support leg. In this case, a water and dirt-tight connection, such as an inductive connection is advantageous.

9 shows a solution for supporting load measurement a force sensor 200 used the pressure of a liquid in a cylinder space 202 measures and from there to the through the piston rod 11 on a volumetric flask 201 that with the cylinder space 202 cooperates, exerted support force closes. To measure the pressure, a pressure sensor is used 91 used that with an evaluation 93 connected to an antenna 92 Has. Measured values for the pressure or already calculated force values can be taken from the evaluation 93 to a display or evaluation device ( 70 in 8th ) in the cab of the machine via radio signal. Preferably, this sensor design is provided with a temperature measuring device (not shown), which determines the temperature of the liquid, so that it is taken into account in the determination of the supporting force. Preferably, the measuring device by a translucent cover 33 also deliver light signals regarding correct mounting or regarding imminent overload or hazard warning as a warning against collisions.

This design of the support foot differs only by the design of the force sensor of the other embodiments. Consequently, the embodiments with an inductive interface or with a cable connection, with such a hydromechanical force sensor 200 be equipped.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2159428 [0004]

Claims (10)

Support force measuring device for measuring a supporting force on a support element of a support structure of a particular mobile machine, with at least one measuring element which is connected to a deformable under the action of the support force deformation body to form a sensor and outputs a support force proportional signal, a support foot containing the sensor and with the support element is movably connected, wherein the support element includes an electrical cable connection, which is adapted for the passage of electrical energy and for transmitting the support force proportional signal to an evaluation device in the machine, characterized in that the support element and the sensor in the support leg have an electromagnetic interface , By means of which the measuring element is supplied via electromagnetic induction with electrical energy from the machine and the support force proportional signal from the measuring element by means of electr Magnetic induction is transmitted to the cable connection of the support element. Support force measuring device according to claim 1, characterized in that the measuring element is connected to a circuit which contains a rechargeable buffer memory for storing electrical energy, which is used for the supporting force measurement and the transmission of the support force proportional signal. Support force measuring device according to claim 2, characterized in that the evaluation device is adapted in the machine, with a time shift between a charging operation for charging the buffer memory and a measuring operation for measuring the buffer memory and a measuring operation for measuring the supporting force with transmission of the support force proportional signal, wherein the switching cycle time-dependent or dependent on the state of charge of the buffer memory or on the size of a measured value for the support force. Support force measuring device according to claim 2, characterized in that the transmission of energy and the transmission of the support force proportional signal takes place at the same time by a modulated AC voltage is transmitted as a carrier wave for the signal via the electromagnetic interface. Support force measuring device according to one or more of the preceding claims 1 to 4, characterized in that the sensor is replaceable installed in the support leg. Support force measuring device according to one or more of the preceding claims 1 to 5, characterized in that the support foot has a ball socket, which is supported on the sensor, wherein the support element has a joint ball which is received in the ball socket. Support force measuring device according to claim 6, characterized in that the stützfußseitige part of the electromagnetic interface is recessed in a recess in the ball socket and the support member side of the electromagnetic interface is recessed sunk in a recess in the ball joint, so that these two parts face each other without contact. Support force measuring device according to one or more of the preceding claims 1 to 7, characterized in that the support element has relatively adjustable sections preferably in the form of a hydraulic piston / cylinder arrangement, the cable, the piston / cylinder assembly is laid by cross, an adjustment of the relative position of the piston and cylinder following changes its length and automatically returns to its original length. Stützkraftmesseinrichtung according to any one of the preceding claims, characterized in that the cable has an initial shape, in which it automatically returns following a decreasing expansion, the initial shape is helical, helical, bellows-shaped zigzag or loop-shaped or has a combination of these basic shapes, or that Cable is wound on an automatic retractor, which rolls up the cable under spring force and preferably in the middle section on both sides. Support force measuring device according to one or more of the preceding claims 1 to 8, characterized in that the sensor is formed from a deformation body, which is formed as a strain gage or as a coupled membrane element with strain gauges or wherein the sensor acting as a hydraulic force sensor from a volumetric flask in a Cylinder space is formed and wherein the pressure in the cylinder chamber is output as the measured value of the supporting force or wherein the sensor evaluates as force measuring axis the acting support forces of the boom of the mobile machine and in this case evaluates the bending of the axle or axle forces on their storage.

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