Force-, in particular load-independent, adjusting device with an energy storage device

Abstract

Energy storage device comprising at least the following components: - at least one load spring (2) to absorb a force, - a load sensor (7) that detects the force acting on the load spring (2), - a volume variator (4) designed as a cylinder with a floating, movable piston (42), wherein the load spring (2) is connected to the volume variator (4) on a compression side (41) such that the pressure on the compression side (41) of the volume variator (4) acts as a counterforce on the load spring (2), - an energy storage device (6) which is coupled to the piston (42) of the volume variator (4) via an adapter on an expansion side, wherein the adapter adapts a force-displacement characteristic of the volume variator (4) with the load spring (2), based on the force detected by the load sensor (7), to the force-displacement characteristic of the energy storage device (6) in such a way that an energy exchange between volume variator (4) and energy storage device (6) is possible with no or only a small force expenditure.

Description

[0001] The invention relates to an energy storage device comprising a load spring, a load sensor, a volume variator, and an energy storage device, as well as a force-load adjustment device, particularly for heavy-duty tables, lifting devices, storage and retrieval systems, suspended lifting systems, crane systems, scissor lift tables, column lift tables, gripping and positioning systems, or handling systems. The adjustment device includes a mechanical energy storage device. The adjustment device enables the adjustment of a load-bearing surface, whereby the force required for the movement is completely or at least largely independent of the actual load.

[0002] Such load balancing devices, particularly as lifting devices, are used in various fields of technology. A wide range of applications are conceivable, from load-independent delivery of workpieces to height-adjustable office furniture.

[0003] Accordingly, a number of devices have already been proposed that include mechanical energy storage devices and are intended to enable load-independent adjustment or at least significantly facilitate height adjustment.

[0004] German patent application DE 203 07 373 U1 describes a height adjustment device for a table. Each of the table legs or a central column consists of at least three telescopic segments. A first gas spring is attached with the lower end of its cylinder to a horizontal base (table leg) and with the upper end of its piston rod to the central telescopic segment. A second gas spring is attached, conversely, with the lower end of its cylinder to the underside of the tabletop and with the upper end of its piston rod also to the central telescopic segment. Both gas springs are connected to each other and to the same pressurized gas reservoir.

[0005] The subject of EP 1 712 828 A2 is a tripod with a spring arm and a parallelogram linkage. Furthermore, an energy storage device is provided, which engages the parallelogram linkage at two pivot points to compensate for a load acting on the parallelogram linkage, so that the device can be moved upwards and downwards with constant force over almost its entire range of motion. For this purpose, at least one of the pivot points is adjustable so that both the preload and the direction of force application of the energy storage device change. In one embodiment, an actuating element is provided that it engages with a control cam formed in a second leg of the parallelogram linkage in such a way that the angular position and spring force of the energy storage device are dynamically influenced when the parallelogram linkage is deflected. The parallelogram linkage disadvantageously necessitates a bulky lever system.

[0006] JP 2000 500 557 A describes a design in which energy is transferred between two disc springs with minimal force. A force-controlled actuator system comprises a positive disc spring and a negative disc spring arranged in series between a load and a reaction element. The positive disc spring is initially in a relaxed state, while the negative disc spring is initially in a loaded state. A movable control device transfers the stored energy from the negative disc spring to the positive disc spring. The combined energy accumulated on both sides of the positive and negative disc springs is used between a reaction element and a load element. The disc springs can be designed such that the energy release rate of the negative disc spring is approximately equal to the energy storage rate of the positive disc spring.One application is intended in the field of couplings in vehicle construction. The use of disc springs adversely limits the travel lengths.

[0007] US Patent 2011 / 0266937 A1 describes a device that can be used to balance loads. The device comprises one or more energy storage devices that can be operated to store energy and, when the load changes, generate a force that compensates for the load change by displacement. A movable element is hinged to one or more of the energy storage devices. The force generated by the one or more energy storage devices is transmitted to the load through the movable element and an associated connection. A variable actuator is connected to one or more of the energy storage devices. In an adjustment mode, the variable actuator is moved, establishing an operative connection between the energy storage device(s) and the movable element. A locking device for the actuator is provided. Various types of springs can be used as energy storage devices.The use of gas springs is explicitly mentioned. The device is intended for use particularly in loading shelving systems. Complex lever systems are used, which limits its possible applications.

[0008] The task, therefore, is to propose an adjustment device with an energy storage device that enables movement with a force largely independent of the load on the device's load-bearing surface. Furthermore, the adjustment device should have a compact design that allows the components to be arranged as independently as possible of their relative positions.

[0009] According to the invention, the problem is solved using an energy storage device according to claim 1. A suitable force-load adjusting device (adjusting device) that operates using the energy storage device is disclosed in claim 20. Advantageous embodiments are described in the dependent claims.

[0010] The energy storage device of the force-load adjustment device has at least the following components: - at least one load spring (preferably a gas spring) to absorb a force, - a load sensor that detects the force acting on the load spring and which is preferably arranged on the load spring, - a volume variator, in particular designed as a cylinder with a floating, movable piston, wherein the load spring is connected to the volume variator on a compression side, such that the pressure on the compression side of the volume variator acts as a counterforce on the load spring, - an energy storage device (spring storage device) which is coupled to the volume variator, in particular to the piston of the volume variator, via an adapter on the expansion side, wherein the adapter adapts the force-displacement characteristic of the volume variator with the load spring, based on the force detected by the load sensor, to the force-displacement characteristic of the energy storage device in such a way that an energy exchange between volume variator and energy storage device is possible with no or only minimal force expenditure,

[0011] Furthermore, the energy storage device may optionally include the following components: - a first locking device that can assume the states "Fixed" or "Released", wherein the first locking device is preferably suitable to fix the load spring in its current mechanical tension state in the "Fixed" state and to release the load spring for changes in the tension state in the "Released" state, - a second locking device that can assume the states "Released" or "Fixed" and that is suitable for releasing or fixing the piston of the volume variator (piston of the cylinder of the volume variator) in its position, - an adjusting device for the piston of the volume variator, wherein the adjusting device moves the piston of the volume variator according to the signals from the load sensor, - a force- or signal-transmitting connection that connects the load sensor to the adjustment device, - a force-transmitting connection that connects the volume variator to the load spring.

[0012] Optionally, a spring (preferably a gas spring) is arranged parallel to the load spring as a damper such that the same force acts on this damper as on the load spring. The first locking device is preferably arranged on (or connected to) this damper and is suitable for fixing the damper in its current mechanical tension state in the "locked" state and for releasing the damper to changes in tension state in the "released" state. The load sensor is also preferably arranged on the damper.

[0013] The force-load adjustment device has at least the following components: - a load-bearing device for receiving the load, or more generally for receiving a force, - Limiting devices for guiding the load during movement, - at least one energy storage device described above, preferably - the load-bearing element is designed as a plate (especially a table or worktop) or gripper, hook, threaded attachment for load fastening or similar holding device for force transmission, - the load spring and optionally also a damper ◯ to engage with a first end at the base, foundation, supporting structure, static element of the lifting or gripping application and with a second end at the load-bearing point, transmitting force; or ◯ with a first end on the base, foundation, supporting structure, static element of the lifting or gripping application and with a second end on a guide gear (also telescopic, articulated) arranged so as to be slidable relative to this on the base, foundation, supporting structure, static element of the lifting or gripping application; or ◯ with a first end on an arranged guide gear (also telescopic, articulated) and with a second end on a second arranged guide gear (also telescopic, articulated) arranged slidably relative to the first arranged guide gear (also telescopic, articulated) transmitting force, so that an expansion of the load spring is converted into an adjusting movement (e.g. lifting movement) of the load-bearing device and a compression of the load spring into a counter-movement (e.g. lowering movement) of the load-bearing device, - the load sensor is preferably a short-stroke cylinder that detects the force exerted on the load-bearing element, wherein the load sensor is rigidly connected to the piston of the gas spring or to an optional damper (preferably also a gas spring), - the adjusting device for the piston of the volume variator, wherein the adjusting device is preferably a long-stroke cylinder whose piston is rigidly coupled to the piston of the volume variator, - the first locking device is suitable for fixing the load spring (the piston if it is designed as a gas spring) and the second locking device is suitable for fixing the piston of the volume variator, wherein the first and the second locking devices are not simultaneously in the same state of "Fixed" or "Released", - the energy storage is a spring storage device, - the force-transmitting connection that connects the load sensor to the adjusting device, preferably a hydraulic line that connects the short-stroke cylinder of the load sensor to the long-stroke cylinder of the adjusting device, - a pneumatic line connects the compression side of the volume variator to the load spring (gas spring).

[0014] The force-load adjustment device preferably has an operating device that acts on the first and second locking devices such that, in a "Hold" position of the operating device, the first locking device is in the "Fixed" state and the second locking device is in the "Released" state, or alternatively, that the operating device is in the "Move" position, with the first locking device in the "Released" state and the second locking device in the "Fixed" state. In the "Hold" state of the operating device, adjustment is blocked. In the "Move" state, adjustment of the load-bearing capacity is possible. The operating device can be permanently attached to the force-load adjustment device or designed as a remote control, in which case it does not need to be permanently connected to the device. The remote control can be wireless or wired. Energy storage device

[0015] The load spring absorbs the force against which work is to be performed in the form of movement against this force. This can be lifting work for adjusting the height of a load, but also displacement work oriented in any spatial direction. The load spring is preferably designed as a gas spring. During periods when no work is to be performed, the load spring can be fixed in its current compressed position (and thus in its tension state). For this purpose, a first locking device is provided. This first locking device is designed according to the prior art and, for example, in the case of gas springs, consists of an overflow preventer that closes the connection between the two chambers of the gas spring. Alternatively, a clamping device on the piston of the gas spring is also suitable.Optionally, a second spring, the damper, is provided, which operates in parallel to the load spring and to which the load sensor and the first locking device are then attached. The load sensor and the first locking device are attached to the load spring if no damper is present. The same force acts on the damper as on the load spring. This is achieved mechanically, for example, by having the load spring and damper support a common load.

[0016] The load sensor detects the force acting on the load spring. In one embodiment, the load sensor is rigidly mounted on the piston of the load spring (gas spring). This results in a mechanical force transmission from the load sensor to the gas spring. This force transmission is not the measured value of the load sensor, even though the value is identical for physical reasons. The measured value of the load sensor is transmitted to the adjustment device. This transmission is carried out using methods according to the prior art and, in its simplest form, depends on the type of sensor; i.e., for example, with an electronic load sensor, the transmission preferably functions electronically. However, it is known to those skilled in the art that any conversion of the signal into other forms (e.g., mechanical to electronic or vice versa) is possible using converters according to the prior art, as are signal amplification or signal transformation, etc.

[0017] In a preferred first embodiment, the load sensor is designed as a short-stroke cylinder. When the load changes, a hydraulic signal is generated (short piston stroke) and transmitted to the adjustment device via a hydraulic line.

[0018] In a second embodiment, the load sensor is designed as a piezoelectric sensor, which emits an electrical signal when the load changes, which is transmitted to the adjustment device (which is then advantageously an actuator motor).

[0019] The volume variator is designed as a floating piston, which is slidably mounted within a cylinder. The piston divides the cylinder into a compression side and an expansion side. The compression side is filled with gas. Movement of the piston towards the compression side thus leads to an increase in pressure on the compression side. Movement of the piston towards the expansion side leads to a decrease in pressure on the compression side of the volume variator. A force transmission to the load spring is applied to the piston on the compression side. Compression therefore exerts a force on the load spring, with this force being opposite to the force acting on the load spring. On the expansion side, force is transmitted via an adapter (e.g., a linkage) to the energy storage device. Furthermore, the adjustment mechanism acts on the piston and is capable of moving it.The second locking device engages the piston or, if present, one of the piston rods, allowing the piston to be fixed in its position. Optionally, the second locking device can also close the pneumatic line between the compression side of the cylinder and the load spring. The first locking device on the load spring or damper and the second locking device on the piston of the volume variator preferably assume alternative states; that is, when one locking device is released, the other is in the "held" (locked) position. In a particularly preferred embodiment, the two locking devices are coupled and actuated by a common control element. This ensures that no incorrect operation is possible.

[0020] In a first embodiment, the load spring is a gas spring and is connected to the volume variator on the compression side of the cylinder via a pneumatic line, so that compression acts as a force on the load spring and expansion acts as a relief on the load spring.

[0021] Alternatively, the load spring can also have a different mechanical design (e.g., a coil spring). The force transmission then occurs, for example, via a piston rod that extends out on the compression side. A mechanical connection to the piston rod on the expansion side of the volume variator cylinder is also possible.

[0022] The energy storage device is a spring-loaded storage system. It can also be designed as a gas spring. However, other mechanical springs are also suitable, especially coil springs, as these (unlike, for example, disc springs) allow for a longer spring travel.

[0023] The energy storage device is connected to the piston of the volume variator via an adapter on the expansion side. Optionally, the energy storage device already has a mechanical preload upon installation.

[0024] The adapter matches the force-displacement characteristic of the volume variator with the load spring to the force-displacement characteristic of the energy storage spring in such a way that energy exchange between the volume variator and the energy storage unit is possible with little or no force. This means that moving the piston in the cylinder of the volume variator requires little or no force. In this context, "little or no force" means that the required force is determined by the internal friction of the system, other physically induced losses, design and manufacturing tolerances, and thermal dependencies, particularly in the case of pneumatic connections or gas springs. Specifically, the required force must be less than the force generated by the adjustment device in conjunction with the load sensor.

[0025] The adapter design can be based on the requirement that a force-free return to the starting position at all times also necessitates ensuring force equilibrium and potential energy balance on both the loading and unloading sides (volume variator and energy storage device) at all times. This results in a transfer function. This transfer function can be implemented, for example, by a gear element (e.g., a coupling gear) that executes its movement according to this transfer function, thus permanently maintaining force equilibrium and potential energy balance on both the loading and unloading sides.

[0026] The adapter is preferably a coupling device, a controlled valve, or a threaded bolt with a thread having a non-constant pitch.

[0027] The linkage mechanism is designed as a cam or linkage mechanism (cam or linkage mechanism in the sense of technical mechanics). The motion of the volume variator piston is preferably transmitted via a piston rod to the corresponding connection point on a link of the linkage mechanism. The energy storage spring is connected analogously. The selection of the gear type and the design of the linkage mechanism are carried out using state-of-the-art methods. Since these depend on the spring characteristics, the required stroke, and other boundary conditions, no universally suitable gear type or design can be specified.

[0028] However, for a wide variety of applications, a linkage mechanism is suitable in which the connection point of the piston rod or the connection point of the energy storage spring is guided in a slotted hole of a gear element, with this connection point simultaneously running in a cam guide that adjusts the lever ratios to adapt the force-displacement characteristics for each point accordingly (see schematic). Fig. 1, Fig. 2) The curve's shape is determined by knowing the two force-displacement characteristics of the volume variator (including the load spring) and the energy storage device, as well as the gear ratios. The curve's shape can then be calculated or determined by computer simulation. As described above, the guiding parameter for calculating the curve's shape is that the resulting force on the piston of the volume variator's cylinder should be equal to or close to zero, but in any case, less than or at most equal to the force applied by the adjusting device.

[0029] If the adapter is a controlled valve, the coupling of the volume variator and energy storage device is preferably hydraulic via the controlled valve. The valve characteristic is preferably stored in an electronic memory. A microcontroller or similar electronic control unit controls the valve opening according to the stored valve characteristic. The stored valve characteristic is determined computationally (computer-aided) or experimentally from the force-displacement curves of the volume variator and energy storage device. The procedure is analogous to that used for a coupling mechanism.

[0030] If the adapter is a threaded bolt with a non-constant thread pitch, the pitch of the thread changes such that the coupling of the volume variator and energy storage device is achieved by a sliding movement of the threaded bolt within a guide. This guide has pins that are supported in the threads of the threaded bolt with the non-constant thread pitch. The thread pitch is calculated such that the displacement of the threaded bolt enables the force-free (or low-force) transfer of energy from the energy storage device to the volume variator or vice versa. The thread pitch is determined by the force-displacement characteristics of both the volume variator (including the load spring) and the energy storage device. The displacement of the threaded bolt with the non-constant pitch can be achieved using a threaded bolt with a constant thread pitch.The threaded bolt with constant pitch is adjusted in its position within a guide ring (by screwing the threaded bolt with constant pitch in or out). The guide ring slides on at least two (preferably at least three, particularly preferably four) guide rods such that end-face contact with the threaded bolt with non-constant pitch can be established. Different forces are required to move the threaded bolts in contact, and these forces depend on the pitch of the threads of the threaded bolt with non-constant cross-section. This allows for the matching of the two force-displacement spring characteristics of the volume variator and the energy storage device.

[0031] The adjusting device moves the piston in the cylinder of the volume variator according to the signals from the load sensor. The adjusting device acts either directly on the piston (e.g., via its own piston rod) or, preferably, on the piston rod that leads to the coupling mechanism.

[0032] In a first embodiment, the adjusting device is a long-stroke hydraulic cylinder whose piston is rigidly coupled to the cylinder or piston rod of the volume variator and which acts against the volume of the volume variator. The long-stroke cylinder is preferably connected to the load sensor, in this case a short-stroke hydraulic cylinder, via a hydraulic line. The adjusting device moves the piston of the volume variator according to the pressure change in the load sensor. Since the short-stroke cylinder, due to its design, generates only low forces, it is necessary that the piston of the volume variator can be moved without significant force. The stroke range of the long-stroke cylinder corresponds to the piston travel of the volume variator. Thus, the long-stroke cylinder can move the piston to any possible position within the cylinder of the volume variator.

[0033] In a second embodiment, the adjustment device is designed as an actuator. In this embodiment, the load sensor is preferably an electronic sensor (e.g., piezoelectric), and the actuator moves the piston of the volume variator according to the signals from the load sensor. An advantage of this embodiment is that the actuator can apply greater forces to adjust the piston of the volume variator. A disadvantage, however, is that an additional electrical power supply is required.

[0034] The energy storage device preferably has an operating device that acts on the first and second locking devices in such a way that, in a "hold" position of the operating device, the first locking device is in the "fixed" state and the second locking device is in the "released" state, or alternatively, that the operating device is in the "move" position, wherein the first locking device is in the "released" state and the second locking device is in the "fixed" state. Force-load adjustment device (load balancing device)

[0035] The load-bearing device is designed to hold the load in a predetermined position and to enable load-independent position adjustment with minimal effort. In a simple embodiment, the load-balancing device is designed as a height-adjustable surface. It incorporates limiting and stabilizing elements known from the prior art (e.g., telescopic supports or similar guides). The limiting elements ensure that the lifting and lowering movements occur in a defined manner (no lateral deflection or tipping). The height adjustment of the load-bearing device is possible within a limited range, which is determined by the stroke lengths of the gas springs or the maximum adjustment lengths of the limiting elements.

[0036] The load-bearing spring is preferably designed as a gas spring and supports the height adjustment of the load-bearing unit from below. The gas spring supports the load during the adjustment process (adjustment of the load-bearing unit's height). The gas spring is adjustable, meaning the gas pressure inside it can be varied. This is achieved via a pneumatic line from the volume variator to the gas spring, through which pressure changes on the compression side (gas side) of the volume variator are transmitted to the gas spring.

[0037] In a first embodiment, the gas spring is provided with a first locking device that prevents height adjustment when the first locking device is triggered. Furthermore, the load sensor is rigidly connected to the piston of the gas spring.

[0038] In a second embodiment, a damper is connected in parallel to the first gas spring.

[0039] This damper is preferably also a gas spring. The damper also assists in load bearing. In this embodiment, the load sensor is rigidly connected to the damper, in particular to the piston of the damper gas spring. The first locking device also acts on the damper in this embodiment.

[0040] The first locking device on the gas spring or damper is coupled to the second locking device on the piston of the volume variator (the second locking device acts on the piston rod here), whereby the two locking devices always assume opposite states (locking / unlocking).

[0041] The load sensor is designed as a force sensor that detects the bearing force on the load-bearing surface. It supports the load-bearing surface from below and measures this bearing force. It is preferably designed as a short-stroke hydraulic cylinder that detects the load on the load-bearing surface by compressing the cylinder's piston and transmitting this force via a hydraulic line to the volume variator's adjustment mechanism. Since the load sensor is located on the piston of the gas spring or damper, force is transmitted to it.

[0042] Alternatively, the load sensor can also be implemented as a different force sensor, e.g., a piezoelectric sensor. The transmission of the load value on the load-bearing surface is then preferably electronic to the adjustment device of the volume variator. Here, too, the load sensor is held by the piston of the gas spring or, optionally, the damper.

[0043] Volume variator, coupling gear and energy storage device corresponding embodiments described in the energy storage device.

[0044] The adjustment device for the piston of the volume variator is preferably designed as a long-stroke cylinder. The maximum stroke of the long-stroke cylinder corresponds to the maximum stroke of the piston in the cylinder of the volume variator. The pistons of the long-stroke cylinder and the volume variator preferably have the same stroke.

[0045] Alternatively, the adjustment device can operate according to other mechanical principles. For example, a motor-driven threaded rod can be used as an adjustment device. A motor-driven adjustment device preferably corresponds to an electronic load sensor, as this enables fully electronic control of the adjustment device. Other approaches are known from the prior art.

[0046] It has been shown that even if an energy surplus is stored in the energy storage device before the force-load adjustment device is put into operation, this surplus is depleted over time due to friction losses and thermal conversion (especially in the pneumatic device components). As a result, the adjustment is no longer supported across the entire adjustment range of the load-bearing capacity. To counteract this, a particularly preferred embodiment provides a latent energy storage device. In a particularly simple embodiment, this latent energy storage device includes a transfer device that feeds energy into the energy storage device. This can be achieved, for example, by transferring the energy via the displacement of the piston of the volume variator in the compression direction while the position of the load-bearing capacity remains unchanged, or by supplying gas to the compression side of the volume variator.The expansion side of the gas spring is supplied with energy during adjustment. A combination of the two approaches is possible. If the energy in the energy storage device is insufficient to achieve the desired adjustment range of the load-bearing capacity, this can be detected by a sensor. At such a moment, the pressure exerted on the load sensor by the load-bearing capacity and the additional force is equal to or greater than the pressure on the compression side of the volume variator. Upon detection of this situation, energy from the latent energy storage device can be fed into the system by pumping an additional quantity of gas (e.g., air or the appropriate working gas) into the compression side of the volume variator or directly into the gas spring. This is preferably done by a micro-pump, which then acts as the transmission device.Optionally, the latent energy storage system features an additional pressure vessel, which is filled by the micro-pump and from which the additional gas is drawn as needed. This additional gas increases the pressure in the load spring, thus assisting the adjustment process. When the load is subsequently returned to its original position in the direction of force, the energy supplied in this way is fed into the energy storage system and remains there until refilling is necessary due to unavoidable thermal and frictional losses, as well as gas losses through leaks. It is also possible that when the force on the load is increased, the piston of the volume variator reaches its end position on the compression side. This condition can be detected (by a sensor), and additional gas can be supplied to the compression side of the volume variator to move the piston back towards the expansion side.The appropriate state-of-the-art sensors are provided for recording the required parameters during the system design.

[0047] It is also possible for the piston of the volume variator to be displaced in the compression direction while the position of the load-bearing element remains unchanged. For this purpose, a transmission device such as an electric motor with a spindle drive, a piezoelectric linear drive, or a magnetic drive can be used. The transmission device preferably engages the piston of the volume variator or, if present, its piston rod.

[0048] A particularly simple embodiment provides a replaceable battery or a replaceable or rechargeable accumulator (via a plug-in power supply) arranged on the force-load adjustment device. The electrical energy from this battery or accumulator can power a micropump, which supplies energy as needed. For this purpose, the micropump preferably pumps air into the load spring or the volume variator on its compression side.

[0049] A particularly preferred embodiment provides for the use of a rechargeable battery charged by a solar cell. Advantageously, the solar cell can be positioned for optimal light absorption. Investigations have surprisingly shown that even a solar cell arrangement at points on the force-load adjustment device not directly illuminated is sufficient to collect enough energy from scattered light to charge the battery. Since adjustments of the force-load adjustment device are not typically performed continuously, and the need for subsequent energy input into the system is quite infrequent (intervals of at least several days, usually months), the energy collected by the solar cell is sufficient to charge the battery.

[0050] Optionally, the force-load adjustment device includes a data processing unit that acquires the sensor signals and, for example, also controls the supply of additional energy via the transmission device. Optionally, the locking devices and the signals from the operating device are also routed through this data processing unit, and the associated processes are controlled. The data processing unit can be, for example, a microcontroller or a simple logic circuit. Preferably, this data processing unit is powered by the battery or accumulator of the latent heat storage device.

[0051] One embodiment provides that the load-bearing element, together with the load spring and the load sensor, forms an actuator unit. This actuator unit is connected to the other elements of the force-load adjustment device according to the invention via a pneumatic line (from the volume variator to the load spring), a signal line (hydraulic or electrical) from the load sensor to the adjustment device, and a line for controlling the first locking device. If a damper is present, it is assigned to the actuator. The elements that do not belong to the actuator then form the variator. This embodiment particularly advantageously allows the actuator and the variator to be arranged at a spatial distance from each other. Furthermore, it is advantageous for a variator to be connected to several actuators. For example, a variator can be arranged on a table (especially a work or lifting table) with two telescopic legs, operating two actuators, one in each telescopic leg.In this case, a pneumatic line runs from the volume variator to each of the individual load springs. Variations of this design involve a pneumatic line extending from the volume variator, with the load springs connected sequentially (or in a daisy-chain) to this line. The signals from the load sensors of different actuators are then combined at the adjustment device. Optionally, the load sensor signals may need to be adjusted so that the adjustment device allocates the necessary share of the volume variator piston control to each sensor. How it works

[0052] The operating principle is explained using the example of a lifting device with a gas spring and a parallel damper (see Fig. 2).

[0053] The lifting device has an operating device that serves to switch between "holding" and "moving".

[0054] Three operating modes are distinguished: 1. Hold 2. Lowering 3. Lifting 1. Set the control device to "Hold"

[0055] The first locking device engages the damper piston and secures it. The second locking device on the piston rod of the volume variator is released. The damper is thus braked. The system is in equilibrium.

[0056] Load changes are compensated for via the control loop. The control loop consists of the load sensor, adjustment device, volume variator (with adapter and energy storage), and gas spring. Due to the damper's braking action, the load-bearing element remains in the set position. The load sensor detects any load changes. The load sensor is designed as a short-stroke cylinder with a nominal stroke of 1 to 5 mm for most applications. However, strokes up to 30 mm are possible for special applications. The load sensor generates hydraulic pressure, which is transmitted to the adjustment device via the corresponding hydraulic connection. The adjustment device is a long-stroke cylinder. The combination of the short-stroke and long-stroke cylinders creates a force reduction, whereby a small stroke with a large load change (e.g., a change in weight force on the short-stroke cylinder) is converted into a large stroke with minimal force.Since little or no force is required to move the piston of the volume variator, the adjusting device moves the piston towards the compression side. The pressure on the compression side increases. This pressure increase is transmitted (unimpeded) to the gas spring, which then develops a force opposing the load on the load-bearing surface. This continues until the spring force equals the load force. The system is then in equilibrium. 2. Set the operating device to "Move" - ​​in the direction of tension of the load spring.

[0057] The first locking device is released, and the damper is no longer braked. Simultaneously, the volume variator is braked (fixed) via its second locking device; that is, the piston of the volume variator is fixed by a brake.

[0058] A force is applied to the load-bearing element to move it. The spring has a constant volume and is tensioned by the moving movement. The same pressure is exerted on the sensor as on the damper. The sensor is connected to the control cylinder via the hydraulic line. Due to its large stroke, which would have to work against the fixed volume variator, it cannot hold a significant amount of hydraulic fluid.

[0059] When the actuator is moved, work is done against the spring. When the control is set to "Hold," the damper is locked and the piston of the volume variator is released. The energy stored in the spring is transferred via the volume variator to the adapter and from there to the energy storage unit. This tensions the compression spring of the energy storage unit. Simultaneously, the sensor detects the contact force and transmits it to the piston of the volume variator via the actuator cylinder. An equilibrium is established between the forces acting on the sensor and the spring, resulting in a stable position of the piston of the volume variator. 3. Set the operating device to "Move" - ​​in the direction of the load spring's release.

[0060] The first locking device is released, and the damper is no longer braked. Simultaneously, the volume variator is braked (fixed) via its second locking device; that is, the piston of the volume variator is fixed by a brake.

[0061] A force is applied to the load-bearing surface to move it. The spring has a constant volume and is pre-tensioned to the degree established by the preceding movement and the adjustment in the holding position. Lifting is performed with the same force that would be required with a lighter load on the load-bearing surface, since the additional load in the "holding" state is compensated for and the gas spring has been pre-tensioned accordingly.

[0062] The same pressure is exerted on the sensor as on the damper. The damper is actively moved or has a slight inherent pressure and follows the movement of the load-bearing device. The sensor is thus relieved of pressure during movement. It is connected to the control cylinder via the hydraulic line. Due to its large stroke, which would have to work against the locked volume variator, it cannot release a significant amount of hydraulic fluid. The sensor therefore remains depressed. However, this changes as soon as the first locking device on the damper is set to "Hold" and consequently the second locking device on the volume variator is set to "Release". At this moment, the force equilibrium is established as described in section 1, and the load sensor is in contact with the load-bearing device. Advantages of the invention

[0063] The adjustment to the load or the force acting on the load spring occurs in the holding state (operating device set to "Hold" -> first locking device engaged, second locking device disengaged). This results in varying degrees of preload on the load spring, and when transitioning to the movement state (operating device set to "Move" -> first locking device disengaged, second locking device engaged), the preload is greater or less, depending on how it adjusted itself due to the load in the holding state, thus facilitating movement or, better yet, making it independent of the load.

[0064] The system is far from a balanced state (equilibrium state) by the progression of the gas spring volume during movement. In a state-of-the-art spring system, this is also always farther from a balanced state by the varying load change, i.e., significantly further. The load change is generally much greater than the progression. The progression is usually much smaller in gas springs than in linear coil springs. This is advantageous. In addition to the force equilibrium (at any point along the displacement path) within the force line between the volume variator, cam mechanism, and spring storage unit, an energy-work equilibrium is achieved at every point in time or at every displacement interval via the cam mechanism. This is only possible due to the special design (topology) of the coupling mechanism.

[0065] The core of the solution to the inventive problem is the change of pressure in the load spring, designed as a gas spring, without additional energy. Since the energy from the first adjustment (work from the outside) is stored and supplied again to assist in the return movement, there is no conflict with the laws of physics. This is achieved with the energy storage device according to the invention.

[0066] To solve the problem, it is also conceivable to combine the aforementioned embodiments appropriately.

[0067] The invention will now be explained in more detail with reference to several exemplary embodiments and accompanying figures. These exemplary embodiments are intended to describe the invention without limiting its scope. Figures Fig. Figure 1 schematically shows an embodiment of the lifting device according to the invention with the energy storage device according to the invention. Fig. Figure 2 schematically shows an embodiment of the lifting device according to the invention with the energy storage device according to the invention and a damper arranged parallel to the load spring. Fig. 3 shows in conjunction with Fig. Figure 1 schematically illustrates the function of the latent energy storage device 9, here with a mechanical displacement of the volume variator piston. The solar cell 91 charges the accumulator 92. If the force differential measurement 932, in conjunction with the end-position monitoring 931 (each via associated sensors), indicates that the stored energy will not be sufficient to lift the load-bearing device 1 to the desired height, the adjustment 933 of the volume variator piston is activated by means of the transmission device 96 (here, for example, an electric motor with spindle drive, a piezoelectric linear drive, or a magnetic drive) to displace the piston 42 of the volume variator 4 towards the compression side 41. The end-position monitoring 931 serves to prevent motor overload and initiates the cessation of the displacement.By moving the piston 42 of the volume variator 4, the gas pressure 97 on the compression side 41 of the volume variator 4 is increased, thus supplying energy. Fig. Figure 4 schematically illustrates the function of the latent energy storage device 9 when a micro-pump 94 is used. The solar cell 91 charges the accumulator 92 via electrical lines 98. When the accumulator is fully or almost fully charged, the micro-pump 94 is activated by the data processing unit 93 to use the energy from the accumulator 92 to fill the pressure vessel 95 with compressed air via the pneumatic pressure line 99. If, during the lifting of the load-bearing device 1, it is detected (by the sensor and control / data processing unit 93) that the energy is insufficient to raise the load-bearing device 1 to the desired height, compressed air is drawn from the pressure vessel 95 and fed into the compression side 41 of the volume variator 4 or the expansion side of the load spring 2 (gas spring). The pressure increase allows the load-bearing device 1 to be raised further, and the necessary energy is supplied to the system. Fig. Figure 5 shows the external form of the load-independent height adjustment device without damper 3 in a technical implementation. Fig. Figure 6 shows the external form of the load-independent height adjustment device with damper 3 in a technical implementation. Fig. Figure 7 schematically shows the arrangement of the most important components in the load-independent height adjustment device without dampers in a technical implementation according to Fig. 5. Fig. Figure 8 schematically shows the division of the load-independent height adjustment device without damper into an actuator 100 and a variator 200. Fig. Figure 9 schematically shows the division of the load-independent height adjustment device with damper into an actuator 100 and a variator 200. Fig. Figure 10 shows an example of a perspective view of a lifting rack in which the load-independent height adjustment device according to the invention (integrated in the rack, therefore not visible) is used. Fig. Figure 11 schematically shows the use of the load-independent height adjustment device according to the invention on the lifting rack. Fig. 10. The load-independent height adjustment device is divided into an actuator (not shown, integrated into the side supports) and a variator 200. Here, one variator 200 operates two actuators. The connection is made via the pneumatic and signal lines (21, 32, 71) shown together. Fig. Figure 12 schematically shows an example circuit in which four actuators 100 are operated by one variator 200. Lines 21, 32, and 71 branch off to the individual actuators 100. Fig. Figure 13 schematically shows another wiring variant of several actuators 100 with a variator 200. Here, each actuator 100 is connected to the variator 200 via its own line group 21, 32, 71. The illustration also serves to demonstrate that the device according to the invention can be used regardless of its orientation. Fig. 14, Fig. 15 to Fig. Figure 16 schematically shows the use of one or more force-load adjustment devices according to the invention on different lifting table constructions. Fig. Figure 14 schematically shows two force-load adjustment devices according to the invention, which support a common load-bearing capacity 1. Fig. Figure 15 shows a force-load adjustment device (2, 3, 100, 200) according to the invention, which supports the load-bearing capacity 1, wherein two telescopic columns 11 act as limiting devices that laterally limit the movement path of the load-bearing capacity. Fig. Figure 16 schematically shows a lifting table construction with a force-load adjustment device (100, 200) according to the invention, in which a scissor frame 12 takes over the function of the limiting device. Fig. Figure 17 schematically shows a gripping device (parallel gripper) in which two movable supports 15 are movably arranged on a portal 14. The force-load adjustment devices according to the invention (characterized here by the load springs 2) are arranged vertically on the supports 15. The force-load adjustment devices clamp a workpiece 13 and move it in two dimensions by coordinated horizontal movement of the supports and / or by coordinated vertical raising and lowering of the force-load adjustment devices. Fig. Figure 18 schematically shows a lifting device in which the force-load adjustment device according to the invention (represented by the load spring 2) is arranged to be horizontally displaceable on a portal 14. The height adjustment (in the direction of the z-axis) is carried out with the force-load adjustment device according to the invention. Fig. Figure 19 shows schematically in a side view the construction of an adapter with a threaded bolt with non-constant pitch 55, a guide 56 and a threaded bolt with constant pitch 57. Fig. Figure 20 schematically shows the adapter according to Fig. 19 in a perspective view. Examples of Implementation: First Example of Implementation

[0068] The exemplary height-adjustable lifting table features a scissor-joint frame (in the style of the Fig. 16) The width of the lifting table platform is 1000–3000 mm and the depth is 800–2000 mm. The lifting table is height-adjustable from 200 mm to 1200 mm or from 600–1600 mm using gas springs. The height adjustment is achieved via a scissor joint as the guide mechanism. An alternative design would be a column guide. The lifting table can support a maximum load of 5000 kg. The lifting table is secured against unintentional activation (raising / lowering).

[0069] The load-bearing element 1, here the tabletop, is supported in its height adjustment by an energy storage device (see Fig. 1) The tabletop 1 is supported by a load spring 2 (gas spring) with a maximum travel of 1200 mm. It engages the base of the table at one end and the underside of the tabletop 1 at the other. The gas spring 2 can be locked in its current position by means of a first locking device 31, which, in the "locked" state, blocks the gas flow between the two chambers of the gas spring 2. A load sensor 7 is arranged on the piston of the gas spring 2. This sensor transmits the weight of the tabletop 1 to the piston of the gas spring 2. The weight of the tabletop 2, including any objects placed on it, is measured by the load sensor 7. The load sensor 7 is a short-stroke hydraulic cylinder with a maximum piston travel of 30 mm. The load sensor 7 is connected to the adjustment device 8, a long-stroke cylinder, via a hydraulic line 71.Its maximum piston stroke is 400 mm and corresponds to the maximum piston stroke of the volume variator 4. The piston of the long-stroke cylinder is connected to the piston rod 43 of the floating piston 42 of the volume variator 4 via the mechanical connection 81 of the adjusting device to the piston. The volume variator 4 and the piston of the long-stroke cylinder reach their end positions simultaneously. The long-stroke cylinder converts the short stroke of the load sensor 7, which occurs when the weight on the tabletop 1 changes, into a longer stroke, which is transmitted via the piston rod 43 to the piston 42 of the volume variator 4. The volume variator 4 has a maximum volume of 20,000 cm³ on the compression side. 3The load spring 2 is connected to the volume variator 4 on the compression side 41 of the piston 42 of the volume variator 4, so that the pressure on the compression side 41 of the cylinder of the volume variator 4 acts as a force on the load spring 2 and is directed opposite to the weight of the tabletop 1 and the objects placed on it. The connection is made via a pneumatic line 21. Air serves as the working gas. The piston rod 43 extends from the volume variator 4 on the expansion side and is connected to the adapter, which in this case is a linkage 5 in the form of a cam mechanism. The control curve 51 traced during the movement of the cam mechanism was calculated by computer simulation, taking into account the force-displacement characteristics of the load spring 2 and the energy storage device 6, which in this case is a helical spring, such that a displacement of the piston 42 of the volume variator 4 can be achieved with only minimal force.A second locking device 82, which can also assume the states "Released" or "Fixed", releases the piston 42 of the volume variator in its position or fixes it.

[0070] The table also features an operating device that can be switched between the two states "Hold" and "Move". In the "Hold" state, the first locking device 31 is in the "Fix" position and prevents movement of the piston of the load spring 2. Simultaneously, the second locking device 82 is in the "Released" state, allowing movement of the floating piston 42 of the volume variator 4. In the "Move" state of the operating device, the switching of the two locking devices 31, 82 is exactly reversed. The operating device actuates the two locking devices (31, 82) by means of Bowden cables (not shown).

[0071] The table also has a latent energy storage capacity 9 (see Fig. 3, Fig. 4) This includes a solar cell array of 91 from 100 - 500 cm² 2 , which is positioned on the underside of the tabletop 1 and stores the collected electrical energy in a Li-polymer battery 92 with a capacity of 300–1200 mWh (3600–14400 mAh). When the battery 92 is at least 90% full, a micro-pump 94 is activated, which pressurizes a pressure vessel 95 with a volume of 100–1000 cm³. 3The pressure vessel 45 is filled with air or technical gas up to a pressure of 40 MPa. Sensors (not shown) are arranged on the table to determine the pressure on the compression side 41 of the volume variator 4 and to detect when the table adjustment or the volume variator 4 reaches its end positions. A further sensor is connected in parallel to the load sensor 7 so that the actual load can be measured. The sensor data is transmitted via cable to a data processing unit 93. This unit is at least an 8-bit microcontroller with 32 k bytes of in-system program memory. The data processing unit 93 also controls one or more valves (not shown) that open or close the pneumatic connection 99 from the pressure vessel 95 to the compression side 41 of the volume variator 4.If the pressure on the compression side 41 of the volume variator 4 is less than the pressure exerted by the table top 1 and the additional weights on the load sensor 7 or the sensor connected in parallel to it, the valve is actuated to supply additional pressure to the compression side 41 of the volume variator 4.

[0072] To adjust the height, the control is set to "Move" and the table height can be adjusted. Then it is set back to "Hold" to fix the table height. The procedure is the same as described in the "Functionality" section. Second embodiment also by analogy

[0073] The reference symbols refer to the figures. Fig. 2, Fig. 3 and Fig. 5.

[0074] The second embodiment essentially corresponds to the first embodiment. However, in the second embodiment, a damper 3 is arranged in parallel with the load spring 2. The damper 3 is also a gas spring, identical in construction to the gas spring used as the load spring 2. The load sensor 7 and the first locking device 31 are arranged on the damper. The load spring now only serves to assist the height adjustment when raising the tabletop 1 and to absorb the energy when lowering the tabletop 1. Reference sign 1 Load capacity 11 telescopic table columns 12 scissor mechanisms of the scissor lift table 13 workpiece 14 Portal 15 movable beams 2 Load spring 3 dampers 31 First locking device of the gas spring or damper 32 Control connection between 31 and 82 - states ("Fixed" and "Released") are always opposite at 31 and 82 4 Volume variator 41 Compression page 42 floating pistons 43 Piston rod 5 coupling gears 51 Control curve 52 gear links 53 Slotted hole 54 Coupling point of the energy storage device to the coupling gear 55 threaded bolts with non-constant thread pitch 56 Leadership 57 threaded bolts with constant thread pitch 6 Energy storage 7 Load sensor 71 hydraulic connection 8 Adjustment device 81 mechanical connection of the adjusting device to the piston 82 second locking device of the piston of the volume variator 9 latent energy storage 9a Charging circuit 9b Rule-Charging Circuit 91 solar cell 92 Accumulator 93 Control / Data Processing Unit 931 End position monitoring (sensor) 932 Force differential measurement and drive control (sensors) 933 Piston stroke with two end positions / adjustment volume variator piston 94 Micro-pump 95 pressure vessels 96 Transmission device (E-motor with spindle drive / piezo linear drive / magnetic drive) 97 Gas pressure 98 electrical lines 99 pneumatic pressure lines 100 actuators 200 variator

Claims

Energy storage device comprising at least the following components: - at least one load spring (2) for receiving a force, - a load sensor (7) that detects the force acting on the load spring (2), - a volume variator (4) designed as a cylinder with a floating, displaceable piston (42), wherein the load spring (2) is connected to the volume variator (4) on a compression side (41) such that the pressure on the compression side (41) of the volume variator (4) acts as a counterforce on the load spring (2), - an energy storage device (6) coupled to the piston (42) of the volume variator (4) on an expansion side via an adapter, wherein the adapter adapts a force-displacement characteristic of the volume variator (4) with the load spring (2), based on the force detected by the load sensor (7), to the force-displacement characteristic of the energy storage device (6) such thatthat an energy exchange between volume variator (4) and energy storage device (6) is possible with no or only minimal force input. Energy storage device according to claim 1, further comprising: - an adjusting device (8) for the volume variator (4), wherein the adjusting device (8) displaces the piston (42) in the cylinder of the volume variator (4) according to the signals of the load sensor (7), - a force- or signal-transmitting connection that connects the load sensor (7) to the adjusting device (8), - a force-transmitting connection that connects the volume variator (4) to the load spring (2). Energy storage device according to claim 1 or 2, further comprising: - a first locking device (31) which can assume the states "Fixed" or "Released", - a second locking device (82) which can assume the states "Released" or "Fixed", and which is suitable to release or fix the piston (42) of the volume variator (4) in its position. Energy storage device according to one of the preceding claims, characterized in that the load spring (2) is a gas spring. Energy storage device according to claim 3 or 4, characterized in that the first locking device (31) is suitable to fix the load spring (2) in its current mechanical tension state in the “Fixed” state and to release the load spring (2) for changes in the tension state in the “Released” state. Energy storage device according to one of the preceding claims, characterized in that the load sensor (7) is arranged on the load spring (2). Energy storage device according to one of the preceding claims, characterized in that the load sensor (7) is a hydraulic short-stroke cylinder or an electronic force sensor. Energy storage device according to claim 7, characterized in that the adjusting device (8) is a long-stroke cylinder whose stroke corresponds to the adjustment stroke of the piston (42) of the volume variator (4) and that a hydraulic line (71) connects the short-stroke cylinder of the load sensor (7) with the long-stroke cylinder of the adjusting device (8) and the adjusting device (8) displaces the piston (42) in the cylinder of the volume variator (4) according to the pressure change in the load sensor (7). Energy storage device according to claim 8, characterized in that the adjusting device (8) is an actuator motor and that an electrical connection connects the load sensor (7) to the actuator motor and the adjusting device (8) displaces the piston (42) in the cylinder of the volume variator (4) according to the electrical signals of the load sensor (7). Energy storage device according to one of the preceding claims, characterized in that the adapter is a coupling mechanism (5) or cam mechanism or a controlled valve or a combination of a threaded bolt (55) with non-constant thread pitch and a threaded bolt (57) with constant thread pitch in a common guide (56). Energy storage device according to one of claims 3 to 10, characterized in that a spring as a damper (3) is arranged parallel to the load spring (2) such that the same force acts on this damper (3) as on the load spring (2) and that the first locking device (31) is suitable to fix the damper (3) in its current mechanical stress state in the "Fixed" state and to release the damper (3) for changes in the stress state in the "Released" state. Energy storage device according to claim 11, characterized in that the load sensor (7) is arranged on the spring of the damper (3) or connected to the damper (3). Energy storage device according to claim 11 or 12, characterized in that the damper (3) is a gas spring. Energy storage device according to one of claims 3 to 13, characterized in that it has an operating device which acts on the first and the second locking device (31, 82) such that in a "hold" position of the operating device the first locking device (31) is in the "fixed" state and the second locking device (82) is in the "released" state or that the operating device is in the "move" position, wherein the first locking device (31) is in the "released" state and the second locking device (82) is in the "fixed" state. Energy storage device according to one of the preceding claims, characterized in that a latent energy storage device (9) is associated with the energy storage device (6), which is configured to feed additional energy into the energy storage device (6) by means of a transmission device (96). Energy storage device according to claim 15, characterized in that the latent energy storage device (9) has a storage device for electrical energy which supplies the transmission device (96) with electrical energy. Energy storage device according to claim 16, characterized in that the storage device for electrical energy is a battery or an accumulator (92). Energy storage device according to one of claims 16 or 17, characterized in that the storage device for electrical energy is designed to be replaceable. Energy storage device according to one of claims 16 to 18, characterized in that the storage device for electrical energy is a battery (92) which is charged by at least one solar cell (91). Force-load adjustment device, comprising at least a load holder, limiting devices for guiding the load holder (1) during the height adjustment of the load holder (1) and an energy storage device according to one of the preceding claims, characterized in that the load spring (2) supports the load holder (1) during the height adjustment. Force-load adjustment device according to claim 20, characterized in that the force-load adjustment device has a data processing device (93) which detects the signals from sensors on the force-load adjustment device and optionally also controls the supply of additional energy via the transmission device (96). Force-load adjustment device according to claim 21, characterized in that the data processing device (93) controls the first and the second locking device (31, 82) and also transmits the signals of the operating device via the data processing device (93) and controls the associated processes from the data processing device (93). Force-load adjustment device according to claim 21 or 22, characterized in that the data processing device (93) is supplied with electrical energy via the battery or accumulator (92) of the latent energy storage device (9). Force-load adjustment device according to one of claims 20 to 23, characterized in that the transmission device (96) is designed to engage the piston (42) of the volume variator (4) during a constant position of the load receiving (1) and to move it in the compression direction. Force-load adjusting device according to one of claims 20 to 24, characterized in that the transmission device (96) is designed to supply gas to the compression side (41) of the volume variator (4) or the expansion side of the load spring (2) during an adjustment of the force-load adjusting device against the load. Force-load adjusting device according to one of claims 20 to 25, characterized in that the energy storage device is divided into an actuator (100) and a variator (200), wherein the actuator (100) comprises at least the load spring (2), the first locking device (31) and the load sensor (7) and the variator (200) comprises at least the remaining components of the energy storage device according to claim 1. Force-load adjusting device according to claim 26, characterized in that the actuator (100) further comprises a damper (3) according to one of claims 11 to 13. Force-load adjusting device according to claim 26 or 27, characterized in that the at least one actuator (100) and the at least one variator (200) are connected to each other by supply lines for the hydraulic connection (21) of the volume variator (4) with the load spring (2), the signal line (71) of the load sensor (7) and the signal line (32) of the first locking device (31). Force-load adjusting device according to one of claims 26 to 28, characterized in that a variator (200) is connected to several actuators (100) by having several hydraulic lines (21) leading from the volume variator (4) to the actuators (200) or by having several actuators (200) connected in series to a hydraulic line. Use of a force-load adjustment device according to one of claims 20 to 29 for use in a lifting rack, a lifting table, a lifting device or a gripping device.

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