A pneumatic actuator

Abstract

A pneumatic actuator (1) comprising a cylinder body (2) having a hollow chamber (5) therein, the chamber having an inlet (6) and an outlet (7). A piston (10) is located within the chamber (5) dividing the chamber into two sections. A piston rod (12) is connected to the piston (10) and extends through the cylinder body (2). A first liner (20) is located within the chamber (5) on one side of the piston (10), and a second liner (21) is located on a second side of the piston (10). The first liner (20) is connected to the inlet (6) and the second liner (21) is connected to the outlet (7). In operation, material is pumped into and out of the liners (20, 21) to expand or contract the liners, thereby moving the piston (10) within the chamber (5) so that the piston rod (12) operates a device.

Description

A PNEUMATIC ACTUATORCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Australian Provisional Patent Application No. 2024902393, titled A pneumatic actuator, filed 1 August 2024, which is hereby incorporated by reference in its entirety.FIELD

[0002] The present invention relates to a pneumatic or hydraulic actuator.BACKGROUND

[0003] Pneumatic actuators are common mechanical devices used to control motion and are used in most industries worldwide. They are typically very reliable, efficient, not overly complicated and safe to use in most environments.

[0004] Pneumatic actuators convert energy into mechanical motion to move something such as a valve for example. They include a cylinder body having a chamber within which a piston attached to a piston rod moves back and forth along the chamber inside the cylinder body. There is an inlet at one end of the cylinder and an outlet at the other. Typically, compressed air, another gas or a fluid medium is pumped into the cylinder to create a pressure differential between the inside of the chamber and the outside atmospheric pressure, once this occurs the piston moves which can be converted to straight or circular motion.

[0005] Pneumatic actuators though have moving parts, tight elastomeric seals and require low tolerance machining to ensure no leakage of the internal medium (typically compressed air or hydraulic fluid). They are also sensitive to damage or malfunction should solid particles become entrained in the medium. Further, when a fluid is involved, it can cause corrosive damage accelerating wear on the cylinder chamber and seals. The current fluids may also be expensive and not environmentally friendly. Typically water is not used as the internal medium as it’s presence may facilitate internal corrosion.

[0006] The invention has been developed primarily for use in industrial applications with actuators and will be described hereinafter with reference thereto. However, it will be appreciated that the invention is not limited to this particular field of use and may be employed in other applications.

[0007] There is a need for a pneumatic / hydraulic actuator that produces longer times between maintenance lowering manufacturing and use costs. There is a need for less accurate machining also reducing costs. A change of the actuator and / or maintenance is expensive and causes workflow downtime which is disruptive to a business. Such downtime also takes labor resources away from other business matters.SUMMARY

[0008] It is an object of the present invention to substantially overcome, or at least ameliorate, one or more of the disadvantages of existing arrangements, or at least provide a useful alternative to existing arrangements.

[0009] There is disclosed herein a pneumatic actuator including: a cylinder body having a hollow chamber therein, the chamber having an inlet and outlet, a piston located within said chamber dividing the chamber into two sections, a piston rod connected to said piston and extending through said cylinder body; a first liner located within said chamber on one side of the piston and a second liner located on a second side of said piston, said first liner connected to said inlet and said second liner connected to said outlet such that in use material is pumped into and out of said liners to expand or contract said liners to move said piston within said chamber so that said piston rod operate a device.

[0010] In one embodiment, the liners are fluidly connected to each other.

[0011] In one embodiment, there are more than two liners.

[0012] In one embodiment, the device is a valve.

[0013] In one embodiment, the fluid is water.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For a more complete understanding of the present invention, exemplary embodiments of the invention are explained in more detail in the following description with reference to the accompanying drawing figures, in which like reference signs designate like parts and in which:

[0015] FIG 1 shows a pneumatic actuator of an embodiment of the present invention in a first configuration;

[0016] FIG 2 shows a pneumatic actuator of an embodiment of the present invention in a second configuration;

[0017] FIG 3 shows a pneumatic actuator of an alternate embodiment of the present invention.

[0018] FIGS 4 and 5 show schematics of a pneumatic system and control systems according to an embodiment.DETAILED DESCRIPTION

[0019] The pneumatic actuator may be utilised in industrial applications involving high cycle actuators. In some cases, the pneumatic actuator eliminates the need for tight tolerance machining of surfaces. The pneumatic actuator may also eliminate the need for internal elastomeric seals. Additionally, the pneumatic actuator may eliminate the need for external elastomeric seals. These features may contribute to reduced manufacturing costs and simplified maintenance procedures. The pneumatic actuator design allows for the use of alternative fluid mediums, which may provide environmental and cost benefits in certain applications. By addressing common issues associated with traditional pneumatic actuators, this design aims to enhance reliability and operational efficiency in industrial settings.

[0020] The pneumatic actuator 1 may comprise a cylinder body 2 with a hollow chamber 5. In some cases, the cylinder body 2 may be cylindrical in shape, though other geometriesmay be possible. The hollow chamber 5 may extend longitudinally through the cylinder body 2, as shown in FIG 1 and FIG 2.

[0021] The hollow chamber 5 may have an inlet 6 and an outlet 7. In some implementations, the inlet 6 and outlet 7 may be positioned at opposite ends of the cylinder body 2, as illustrated in FIG 1 and FIG 2. The inlet 6 and outlet 7 may allow for the introduction and removal of material into and out of the hollow chamber 5.

[0022] In some cases, the pneumatic actuator 1 may include seals at the inlet 6 and the outlet 7. These seals may prevent leakage of the material used within the pneumatic actuator 1. The seals may be made of various materials suitable for maintaining a fluid-tight connection.

[0023] The cylinder body 2 may be designed with access ports or removable end caps that allow for the replacement of liners without disassembling the entire cylinder body 2. These access features may include threaded connections, quick-release mechanisms, or hinged panels that can be opened to provide direct access to the liners 20, 21 within the hollow chamber 5. Once accessed, the worn or damaged liners can be detached from their connections to the inlet 6 and outlet 7, removed through the access points, and new liners can be installed in their place. This modular design feature significantly facilitates maintenance procedures, reduces downtime during liner replacement, and minimizes the specialized tools and technical expertise required for servicing the pneumatic actuator 1.

[0024] In some implementations, the liners within the hollow chamber 5 may be configured to withstand pressures up to 10 bar. This pressure resistance may allow the pneumatic actuator to operate effectively in high-pressure applications.

[0025] The pneumatic actuator 1 may include a pressure relief valve connected to at least one of the liners. This pressure relief valve may prevent over-pressurization within the hollow chamber 5, enhancing the safety and longevity of the pneumatic actuator 1.

[0026] The pneumatic actuator 1 may include a piston 10 located within the hollow chamber5. In some cases, the piston 10 may divide the hollow chamber 5 into a first chambersection 17 and a second chamber section 18, as illustrated in FIG 1 and FIG 2. The piston 10 may be configured to move along the longitudinal axis of the hollow chamber 5.

[0027] A piston rod 12 may be connected to the piston 10. The piston rod 12 may extend through the cylinder body 2, as shown in FIGs 1 to 3. In some implementations, the piston rod 12 may extend through one end of the cylinder body 2. In other cases, the piston rod 12 may extend through both ends of the cylinder body 2, which may provide double-acting operation.

[0028] The piston rod 12 may be configured for translation movement relative to the cylinder body 2. This translation movement may allow the piston rod 12 to move in a linear or translational fashion along the longitudinal axis of the hollow chamber 5. In some cases, and as shown in an alternative embodiment in FIG 3, the piston rod 12 may also be configured for rotational movement relative to the cylinder body 2. This rotational capability may enable the piston rod 12 to rotate around its own axis. This will be described in further detail below.

[0029] The movement of the piston 10 and piston rod 12 within the hollow chamber 5 may produce different types of motion. In some implementations, the pneumatic actuator 1 may produce straight motion, where the piston rod 12 moves in a linear path, as shown in FIG 1 and FIG 2. In other cases, the pneumatic actuator 1 may produce circular motion, which may be achieved through the rotational movement of the output shaft 12, as shown in FIG 3.

[0030] The piston rod 12 may be designed to operate a device. In some cases, the device operated by the piston rod 12 may be a valve. The movement of the piston rod 12, whether translational or rotational, may be used to control the opening and closing of the valve or to adjust its position.

[0031] The pneumatic actuator 1 may include a first liner 20 and a second liner 21 positioned within the hollow chamber 5, as illustrated in FIG 1 and FIG 2. In some cases, the first liner 20 may be located within the first chamber section 17 on one side of the piston 10. The second liner 21 may be located within the second chamber section 18 on a second side of the piston 10.

[0032] The first liner 20 may be connected to the inlet 6, while the second liner 21 may be connected to the outlet 7. This configuration may allow for the introduction and removal of material into and out of the liners 20, 21 through the inlet 6 and outlet 7, respectively.

[0033] In some implementations, the first liner 20 and the second liner 21 may be made of an elastic material. The elastic material may allow the liners 20, 21 to expand and contract within the hollow chamber 5. In some cases, the elastic material of the liners 20, 21 may be rubber, which may provide durability and flexibility.

[0034] The liners 20, 21 may be designed as inflatable bags within the hollow chamber 5. This design may allow the liners 20, 21 to expand when filled with material and contract when the material is removed.

[0035] In some cases, the liners 20, 21 may be fluidly connected to each other. This fluid connection may allow for the transfer of material between the liners 20, 21, potentially enhancing the efficiency of the pneumatic actuator 1.

[0036] The pneumatic actuator 1 may, in some implementations, include more than two liners within the hollow chamber 5. Additional liners may provide increased control over the movement of the piston 10 or allow for more complex actuation patterns.

[0037] The material pumped into and out of the liners 20, 21 may be a non-corrosive fluid. The use of a non-corrosive fluid may help to extend the lifespan of the liners 20, 21 and other components of the pneumatic actuator 1. In some cases, water may be used as the non-corrosive fluid, providing a cost-effective and environmentally friendly option.

[0038] In the embodiment illustrated in FIG 3, the piston rod 12 may extend into the hollow chamber 5 and may be connected to a gear 14 positioned within the chamber. The gear 14 may be configured to mesh with a pair of racks 16 that are positioned within the hollow chamber 5. The racks 16 may be arranged on opposite sides of the gear 14, allowing for bidirectional engagement.

[0039] The first liner 20 and the second liner 21 may be positioned adjacent to the racks 16 within the hollow chamber 5. When material is pumped into the first liner 20, the firstliner 20 may expand and exert force against one of the racks 16. This expansion may cause the rack 16 to move linearly within the hollow chamber 5. As the rack 16 moves, it may engage with the gear 14, causing the gear 14 to rotate.

[0040] Conversely, when material is pumped into the second liner 21, the second liner 21 may expand and exert force against the other rack 16. This may cause the second rack 16 to move in the opposite direction, which may result in rotation of the gear 14 in the opposite direction. The deflation of either liner 20, 21 may allow the corresponding rack to return to its original position.

[0041] The rotational movement of the gear 14 may be transmitted to the piston rod 12, enabling the piston rod 12 to rotate about its longitudinal axis. This configuration may convert the linear expansion and contraction of the liners 20, 21 into rotational motion of the piston rod 12. In some implementations, this rotational motion may be used to operate rotary devices, such as rotary actuators or other equipment requiring angular positioning.

[0042] The gear 14 and rack 16 arrangement may provide mechanical advantage, allowing for precise control of the rotational position of the piston rod 12. The degree of rotation may be proportional to the amount of material introduced into or removed from the liners 20, 21, enabling fine control over the operated device.

[0043] In some implementations, the pneumatic actuator 1 may be integrated into a pneumatic system 40, as illustrated in FIGS. 4 and 5. In Figure 4, the pneumatic system 40 may comprise a pump 30 that provides the driving force for material circulation within the system. The pump 30 may be fluidly connected to other components of the pneumatic system 40 to enable controlled operation of the pneumatic actuator 1.

[0044] The pneumatic system 40 may include a control system 42 that manages the operation of various system components. The control system 42 may comprise a controller 44 that serves as the central processing unit for coordinating system operations. In some cases, the controller 44 may be configured to receive input signals and generate output commands to regulate the flow of material within the pneumatic system 40.

[0045] The control system 42 may include one or more sensors 46 positioned at strategic locations within the pneumatic system 40. These sensors 46 may be configured to monitor various operational parameters and provide feedback to the controller 44. The sensors 46 may detect conditions such as pressure levels, flow rates, velocity or positional information related to the operation of the pneumatic actuator 1.

[0046] In some implementations, the pneumatic system 40 may include a directional control valve (DCV) 48 that regulates the flow of material between different components. The DCV 48 may be positioned between the pump 30 and the pneumatic actuator 1, allowing for controlled distribution of material to the first liner 20 and second liner 21. The DCV 48 may be operated by the controller 44 based on feedback received from the sensors 46.

[0047] The controller 44 may process signals from the sensors 46 and determine appropriate control actions for the DCV 48. This feedback control arrangement may enable precise positioning of the piston 10 within the hollow chamber 5 and accurate operation of devices connected to the piston rod 12. The integration of these components within the control system 42 may provide automated operation capabilities and enhanced system reliability.

[0048] In some cases, the process of inflating or deflating the first liner 20 and the second liner 21 may be accomplished by use of the pump 30. The pump 30 may introduce material into the first liner 20 through the inlet 6, causing the first liner 20 to inflate. Simultaneously or subsequently, the pump 30 may remove material from the second liner 21 through the outlet 7, causing the second liner 21 to deflate.

[0049] This coordinated inflation and deflation of the first liner 20 and the second liner 21 may result in precise control over the movement of the piston 10 within the hollow chamber 5. The movement of the piston 10 may be translated into linear or rotational motion of the piston rod 12, depending on the specific configuration of the pneumatic actuator 1.

[0050] In some implementations, the pneumatic system 40 may include additional processing and control components, as illustrated in FIG. 5. The pneumatic system 40 may comprise a processor 50 that serves as a computational unit for managing system operations. Theprocessor 50 may be configured to execute control algorithms and process data related to the operation of the pneumatic actuator 1.

[0051] The pneumatic system 40 may include memory 52 that stores program instructions, operational parameters, and system data. The memory 52 may be operatively connected to the processor 50 to provide data storage and retrieval capabilities for system operation. The memory may be in the form of random access memory (RAM), for example.

[0052] A bus 54 may provide communication pathways between various components within the pneumatic system 40. The bus 54 may facilitate data transfer between the processor 50, memory 52, and other system components, enabling coordinated operation of the pneumatic system 40.

[0053] The pneumatic system 40 may include an input / output (I / O) interface 56 that manages communication between internal system components and external devices. The I / O interface 56 may be connected to the bus 54 and may facilitate data exchange with external sensors, control devices, or monitoring equipment.

[0054] The controller 44 may be connected to the I / O interface 56, allowing for integration with the processor 50 and memory 52. This configuration may enable the controller 44 to access computational resources and stored data for enhanced control capabilities of the directional control valve 48 and pump 30.

[0055] The pump 30 may remain fluidly connected to the directional control valve 48, which continues to regulate material flow to the pneumatic actuator 1. The fluid connection is represented by the arrow in FIG 5. The integration of the processor 50, memory 52, bus 54, and I / O interface 56 may provide advanced control capabilities, data logging, and system monitoring functions for the pneumatic system 40.

[0056] Alternate embodiments will now be described. In some examples, the piston rod may be more correctly termed an 'output shaft' for this type of actuator. Also, a central 'bag' between the pistons is needed on Fig 3 in some cases. Also, the two end cavities may either have 'bags' as drawn or have springs working against the central 'bag'. In someexamples, the supply system will have safety relief. In many cases the pump and control system are separate and common.

[0057] In some alternate embodiments, the pneumatic actuator 1 may include multiple pistons 10 within the hollow chamber 5. Each piston 10 may be connected to separate piston rods 12, allowing for independent operation of multiple devices simultaneously. This configuration may provide enhanced functionality in applications requiring coordinated movement of several components.

[0058] The cylinder body 2 may, in some variations, have a non-cylindrical cross-section. For example, the cylinder body 2 may have a rectangular, oval, or other geometric crosssection that may be suitable for specific applications or space constraints.

[0059] In certain implementations, the liners 20, 21 may be arranged in a nested configuration within the hollow chamber 5. This arrangement may allow for multiple stages of expansion and contraction, potentially providing finer control over the movement of the piston 10.

[0060] The pneumatic actuator 1 may include variable-volume liners in some embodiments. These liners may be designed with different expansion characteristics, allowing for nonlinear movement profiles of the piston 10 as material is introduced or removed.

[0061] In some cases, the pneumatic actuator 1 may incorporate a bypass valve system that allows material to flow directly between the first liner 20 and the second liner 21 without passing through external pumping equipment. This configuration may enable rapid repositioning of the piston 10 or emergency operation modes.

[0062] The piston 10 may, in certain embodiments, include integrated sensors or measurement devices. These components may provide direct feedback about the position, velocity, or acceleration of the piston 10 within the hollow chamber 5.

[0063] In some variations, the liners 20, 21 may be constructed with reinforced sections or varying wall thicknesses. This design may allow for controlled deformation patternsduring expansion and contraction, potentially improving the precision of piston 10 movement.

[0064] The pneumatic actuator 1 may include modular liner assemblies in certain implementations. These assemblies may allow for quick replacement or reconfiguration of the liners 20, 21 without requiring complete disassembly of the cylinder body 2.

[0065] In some embodiments, the material used within the liners 20, 21 may be a gas rather than a liquid. The use of compressed air or other gases may provide different operational characteristics, such as faster response times or reduced weight of the overall system.

[0066] The pneumatic actuator 1 may incorporate temperature compensation features in certain variations. These features may account for thermal expansion or contraction of the materials used in the liners 20, 21 or the cylinder body 2, maintaining consistent performance across different operating temperatures.

[0067] In use, this invention, at least in a preferred embodiment, is mechanical and less prone to complications, and is expected to be far lower cost. It relies on internal inflatable ‘bags’ or “liners” 20,21 either side of the piston 10 which receive the driving force fluid, as opposed to the current machined chambers. This is expected to greatly reduce the cost of internal components, and containing the medium / fluid will reduce corrosive deterioration. Containing the medium / fluid also allows the potential use of water as the medium, producing a cost and environmental benefit over industry wide hydraulic oil usage.

[0068] Advantageously, the invention, at least in a preferred form, produces actuators with potentially longer times between maintenance in such applications, while lowering manufacturing costs. The distinct features greatly reduce or eliminate the need for machined parts to form a tight seal both internally and between the actuator and outside environment. It provides the removal of the need for tight tolerance machining of surfaces and internal elastomeric seals, the removal of the need for tight tolerance machining of surfaces and external elastomeric seals, the elimination of seals produces fewer spare parts and foreign particles and debris in the actuating fluid cannot damage the seals / intemal mechanisms.

[0069] Although specific embodiments of the invention are illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternative and / or equivalent implementations exist. It should be appreciated that the exemplary embodiment or exemplary embodiments are examples only and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

[0070] It will also be appreciated that in this document the terms “comprise”, “comprising”, “include”, “including”, “contain”, “containing”, “have”, “having”, and any variations thereof, are intended to be understood in an inclusive (i.e. non-ex elusive) sense, such that the process, method, device, apparatus or system described herein is not limited to those features or parts or elements or steps recited but may include other elements, features, parts or steps not expressly listed or inherent to such process, method, article, or apparatus. Furthermore, the terms “a” and “an” used herein are intended to be understood as meaning one or more unless explicitly stated otherwise. Moreover, the terms “first”, “second”, etc. are used merely as labels, and are not intended to impose numerical requirements on or to establish a certain ranking of importance of their objects.REFERENCE NUMERALS1 pneumatic actuator 21 second liner2 cylinder body 30 pump5 hollow chamber 40 pneumatic system6 inlet 42 control system7 outlet 44 controller10 piston 46 sensors12 piston rod 48 directional control valve (DCV)14 gear 50 processor16 pair of racks 52 memory17 first chamber section 54 bus18 second chamber section 56 input / output (I / O) interface20 first liner

Claims

CLAIMS1. A pneumatic actuator comprising: a cylinder body having a hollow chamber therein, the chamber having an inlet and an outlet; a piston located within said chamber dividing the chamber into two sections; a piston rod connected to said piston and extending through said cylinder body; a first liner located within said chamber on one side of the piston; a second liner located on a second side of said piston, said first liner connected to said inlet and said second liner connected to said outlet, wherein material is pumped into and out of said liners to expand or contract said liners to move said piston within said chamber so that said piston rod operates a device.

2. The pneumatic actuator of claim 1, wherein the liners are fluidly connected to each other.

3. The pneumatic actuator of claim 1 or claim 2, wherein there are more than two liners.

4. The pneumatic actuator of any one of claims 1 to 3, wherein the device is a valve.

5. The pneumatic actuator of any one of claims 1 to 4, wherein the material pumped into and out of the liners is a liquid.

6. The pneumatic actuator of claim 1, wherein the first liner and the second liner are made of an elastic material.

7. The pneumatic actuator of claim 6, wherein the elastic material is rubber.

8. The pneumatic actuator of claim 1, wherein the inlet and the outlet is configured for coupling to a pump.

9. The pneumatic actuator of claim 1, wherein the piston rod is configured for translation movement relative to the cylinder.

10. The pneumatic actuator of claim 1, wherein the piston rod is configured for rotational movement relative to the cylinder.

11. The pneumatic actuator of any one of claims 1 to 10, further comprising seals at the inlet and the outlet to prevent leakage of the material.

12. The pneumatic actuator of any one of claims 1 to 11, wherein the liners are configured to be replaceable without disassembling the cylinder body.

13. The pneumatic actuator of any one of claims 1 to 12, wherein the material is a non- corrosive fluid.

14. The pneumatic actuator of any one of claims 1 to 13, wherein the piston rod extends through both ends of the cylinder body to provide double-acting operation.

15. The pneumatic actuator of any one of claims 1 to 14, wherein the liners are configured to withstand pressures up to 10 bar.

16. The pneumatic actuator of any one of claims 1 to 15, further comprising a pressure relief valve connected to at least one of the liners to prevent over-pressurization.

17. A pneumatic system comprising: a pneumatic actuator according to any one of claims 1 to 16; and a pump fluidly coupled to the liners for pumping material into and out of the liners.

18. The pneumatic system of claim 17, wherein the pump is configured to be controlled by a control system to regulate the movement of the piston.

19. The pneumatic system of claim 18, further comprising the control system.

20. The pneumatic system of claim 19, wherein the control system comprises one or more sensors configured to monitor at least one of speed and displacement of the piston relative to the chamber, and wherein the control system regulates operation of the pump based on feedback from the one or more sensors.

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