Abstract:
A pneumatic actuator unit concept is disclosed which includes a unitary structure that has single or dual inflatable pneumatic air chambers mounted on and fixed to a common central base member or plate member that provides a base for the air chambers. Dual air chambers can apply force in different directions with respect to the base member. The operating air is supplied by way of access ports located in the central base member which also includes an integral internal control valve system. The air chambers are preferably airbag devices which may be sleeve-type airbags, single or multiple convoluted airbags or other inflatable apparatuses.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
     Not applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to the field of pneumatic actuators suitable for use in various types of machinery or other devices for providing deployment and retraction forces during use. More specifically, the present invention relates to a pneumatic actuating system having a mounting base adapted to carry one or more inflatable pneumatic chambers that are controlled by an internal control valve system located in the mounting base. Opposed pneumatic chambers enable bi-directional operation. 
     II. Related Art 
     Pneumatic actuating systems of a variety of types have been associated with the operation of many devices for some time, including mechanical implements of varying kinds. An example of such a concept is illustrated and described in U.S. Pat. No. 8,534,373 B2, which shows the use of multiple airbag units to deploy and retract a variety of field-conditioning implements. It would provide a distinct advantage if a compact bi-directional pneumatic actuating unit could be provided with an integral internal control valve system to deploy and retract various devices. 
     SUMMARY OF THE INVENTION 
     By means of the present invention, there is provided a pneumatic actuator unit concept which includes a unitary structure that has single or dual inflatable pneumatic air chambers mounted on and fixed to a common central base member or plate member that provides a base for the air chambers. Dual air chambers can apply force in different directions with respect to the base member. The operating air is supplied by way of access ports located in the central base member which also includes an integral internal control valve system. The air chambers are preferably airbag devices which may be sleeve-type airbags, single or multiple convoluted airbags or other inflatable apparatuses. 
     The pneumatic actuating units of the present invention may be mounted in an arrangement in which the position of each of the remote ends of opposed pneumatic chambers is fixed so that the central base member can be used to apply force and move a load according to the inflation of the opposed pneumatic chambers. Preferably, the pneumatic actuating units are mounted in a manner that fixes the position of the central base member and allows the ends of the opposed pneumatic chambers remote from the central base member to apply force based on the inflation of the opposed pneumatic chambers and apply force to a load accordingly. 
     Embodiments include a double-acting airbag system that incorporates a mounting arrangement that has a central base adapted to carry a pair of airbags mounted on opposite sides of the central base. The central base further includes an internal control valve system and is adapted to be connected to at least one source of pressurized air. The valve system is configured to selectively supply pressurized to and cause air to be exhausted from each of the pair of airbags. 
     The double-acting airbag system of the invention includes arrangements in which only one selected opposed airbag can be inflated at a time. This type of arrangement may have a single air inlet or a plurality of air inlets. With multiple air inlets, the airbags can be operated at more than one selected pressure. In other arrangements the airbags can be inflated and exhausted independently and operated at the same or at different pressures. A further embodiment may employ a single airbag. In all of the embodiments, the control valves and access ports for the airbags are contained in the base and the assembly needs only to be supplied with pressurized air and electric control power, if necessary. 
     The internal control valve systems preferably include one or more two-position spool valves which are preferably solenoid operated between a normal or power-off position and a shifted position when the solenoid is energized. While solenoid-operated valves are preferred, other valve operating systems including air piloted spool valves, may be used. 
     It should be noted that inflatable pneumatic actuator in the form of conventional airbags have been found to be a preferred type of pneumatic operator, but other such devices could also be used. 
     The term “pneumatic actuator” or “pneumatic operator,” as used herein is defined to mean a device which translates the energy from a compressed air supply into a linear or rotary force or movement. 
     The term “airbag”, as used herein, is defined to mean any type of inflatable pneumatic operator, without limitation, including convoluted and non-convoluted devices with single and multiple air access ports, and ports at different locations. Single and double-acting units are also included. The present invention employs opposed units which may function as lift and down-force airbags. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing features and advantages of the invention will become apparent to those skilled in the art from the following detailed description of one or more preferred embodiments, especially when considered in conjunction with the accompanying drawings in which like numerals depict like parts: 
         FIGS. 1A and 1B  are cut away side views that depict a first embodiment of the invention in the form of a double-acting airbag in which one airbag can be inflated at a time, shown with the spool valve in the normal position and the lower airbag inflated; 
         FIG. 1C  is a top cut away image of the central base assembly of  FIGS. 1A and 1B ; 
         FIG. 1D  is a bottom cut away image of the central base assembly of  FIGS. 1A and 1B ; 
         FIGS. 2A-2D  are figures similar to  FIGS. 1A-1D  with the spool valve in the shifted or energized position and the upper airbag inflated; 
         FIGS. 3A and 3B  are cut away side views of a slightly modified second embodiment of the invention in which one airbag can be inflated at a time but in which a plurality of pressures can be selected for each airbag shown with the spool valve in the normal position and the lower airbag inflated; 
         FIG. 3C  is a top cut away image of the central base assembly of  FIGS. 3A and 3B ; 
         FIG. 3D  is a bottom cut away image of the central base assembly of  FIGS. 3A and 3B ; 
         FIGS. 4A-4D  are figures similar to  FIGS. 3A-3D  with the spool valve in the shifted or energized position and the upper airbag inflated; 
         FIGS. 5A and 5B  are cut away side views that depict another embodiment of a double-acting airbag system according to the invention which includes dual solenoid-operated spool valves, both shown in the normal un-energized position this embodiment includes one intake and two exhaust ports; 
         FIGS. 5C and 5D  are top and bottom cut away views, respectively, of the central base assembly of  FIGS. 5A and 5B ; 
         FIGS. 6A-6D  are figures similar to  FIGS. 5A-5D  with both spool valves in the shifted or energized position and both airbags open to exhaust; 
         FIGS. 7A-7D  are figures similar to  FIGS. 5A-5D  with the upper airbag inflated and the lower airbag collapsed; 
         FIGS. 8A-8D  are figures similar to that in  FIGS. 5A-5D  with the lower airbag inflated and the upper airbag collapsed; 
         FIGS. 9A and 9B  are cut away side views that depict yet another variation of a double-acting airbag system according to the invention which includes dual solenoid-operated spool valves with two intake and two exhaust ports the two intake ports are connected to different sources of air with the spool valves in the normal, un-energized state; 
         FIGS. 9C and 9D  are top and bottom cut away views, respectively, of the central base assembly of  FIGS. 9A and 9B ; 
         FIG. 10A-10D  are figures similar to  FIGS. 9A-9D  with both spool valves in the shifted or energized position and both airbags open to exhaust and collapsed; 
         FIGS. 11A-11D  are figures similar to  FIGS. 9A-9D  with the upper airbag inflated and the lower airbag collapsed; 
         FIGS. 12A-12D  are figures similar to  FIGS. 9A-9D  with the lower airbag inflated and the upper airbag collapsed; 
         FIG. 13A  is a perspective view of another airbag assembly embodiment in which two spool valves operate the airbag and a pressure sensor is included; 
         FIG. 13B  is a top view of the airbag assembly of  FIG. 13A ; 
         FIG. 13C  is a sectional view along B-B of  FIG. 13B ; 
         FIG. 13D  is a sectional view along A-A of  FIG. 13B ; 
         FIG. 14A  is a top view of an airbag assembly similar to  FIG. 13B ; 
         FIG. 14B  is a sectional view showing the access of a pressure sensor; 
         FIG. 15  is a perspective view of a double-acting airbag version of the assembly of  FIG. 14A ; 
         FIG. 16A  is a top view of the airbag assembly of  FIG. 15 ; 
         FIG. 16B  is a sectional view along B-B of  FIG. 16A  showing inlet valves in their normal position; 
         FIG. 16C  is a sectional view along A-A of  FIG. 16A  showing exhaust valves in their normal position; 
         FIG. 17A  is a top view of an airbag assembly similar to  FIG. 16A ; 
         FIG. 17B  is a sectional view along lines C-C of  FIG. 17A  showing pressure sensors and access openings to airbags; 
         FIG. 18A  is a top view similar to  FIG. 16A  to illustrate different side cut away sectional views; 
         FIGS. 18B and 18C  are left and right cut away sectional views from  FIG. 18A  showing intake and exhaust valves, respectively, with the embodiment in the pressure lowering or deflating for both airbags; 
         FIGS. 19A-19C  are views similar to  FIGS. 18A-18C  showing intake and exhaust valves in cut away sectional views with the system in the inflate mode for both airbags; 
         FIGS. 20A-20C  illustrate a pair of double-acting airbags in accordance with the invention in an assembly in which the outer ends are constrained and the central bases are free to raise and lower moving a connected member; and 
         FIGS. 21A-21D  illustrate another assembly in which an axle assembly is raised and lowered using a pair of double-acting airbags in which the central bases are fixed and the outer ends of the airbags control the movement of the axle. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description of the illustrative embodiments is intended to illustrate representative examples of the inventive concepts and is not intended to exhaust or limit the scope of those concepts. The examples are to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top” and “bottom”, “left” and “right”, as well as derivatives thereof (e.g., “horizontally”, “downwardly”, “upwardly”, etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “connected”, “connecting”, “attached”, “attaching”, “join” and “joining” are used interchangeably and refer to one structure or surface being secured to another structure or surface or integrally fabricated in one piece, unless expressively described otherwise. 
     One embodiment of the invention is depicted in  FIGS. 1A-1D and 2A-2D . In  FIGS. 1A-1D  there is shown a double-acting airbag system, generally at  30  that includes a central base  32  adapted to carry a pair of airbags mounted on the central base. These include an upper airbag  34  and a lower airbag  36 . The central base includes a spool valve assembly  38  with solenoid operator  40  and biasing spring  42  electrical connections are shown at  44  and  46 . The central base  32  also includes a single air entry or supply port  48 , on upper exhaust port  50  and a lower exhaust port  52 . Arrows are used to show nominal directions of air flow. In  FIGS. 1A-1D  the lower airbag  36  is inflated and the upper airbag  34  is collapsed. Thus, air is depicted as entering the lower bag through an internal lower bag port  54  and leaving the upper airbag through upper bag port  56  and exhaust port  50 . 
     Conversely, in  FIGS. 2A-2D , the solenoid  40  is energized and the spool valve is shifted compressing the spring  42 , the upper airbag  34  is inflated and the lower airbag  36  is collapsed. Air is depicted as entering the upper airbag through an upper internal top bag port  56  and leaving the lower airbag  36  via lower bag port  54  and exhaust port  52 . 
       FIGS. 3A-3D and 4A-4D  depict an embodiment similar to that of  FIGS. 1A-1D  with certain modifications. Thus, in this embodiment, there are two intake ports  60  and  64  and two exhaust ports  62  and  66 . The lower airbag  36  is accessible to inlet port  60  and outlet or exhaust port  62  and upper airbag  34  is accessible to inlet port  64  and exhaust port  66 . By incorporating two inlet ports  60  and  64 , two separate sources in pressurized air can be supplied and the upper and lower airbags can be inflated at different pressures. The  FIGS. 3A-3D  show the spool valve in the normal position with the solenoid not energized and the lower airbag  36  inflated and the upper airbag  34  collapsed. Conversely,  FIGS. 4A-4D  show the spool valve shifted with the solenoid energized. The upper airbag  34  is inflated and the lower airbag  36  is collapsed. 
       FIGS. 5A-8D  depict an alternate embodiment of a double-acting airbag system according to the invention in which dual solenoid operated spool valves are incorporated along with one intake and two exhaust ports. This embodiment enables independent operation of the upper and lower airbags. 
     In  FIGS. 5A and 5B  there is shown another embodiment of a double-acting airbag system, generally at  80 , that includes a central base  82  adapted to carry a pair of opposed airbags mounted on the central base. These include an upper airbag  84  and a lower airbag  86 . The central base includes a pair of spool valve assemblies  88  and  90  with solenoid operators  92  and  94  and return springs  96  and  98 , respectively, as best shown in the cut away views of  FIGS. 5C and 5D . This embodiment includes a single intake port  100  and upper and lower airbag exhaust ports  102  and  104 , respectively. The upper airbag  84  is operated by the spool valve assembly  90  and the lower airbag is operated by the spool valve assembly  88 . 
       FIGS. 5A-5D  depict the system with both of the spool valves in the normal, unenergized position and the return springs extended. This connects the intake port  100  with both the upper internal bag port  106  and lower internal bag port  108  allowing both airbags to inflate. In the  FIGS. 6A-6D , both of the spool valve solenoids  92  and  94  are energized shifting the associated spool valves  88  and  90  thereby connecting both airbags to their respective exhaust ports allowing both airbags to collapse. Electrical connections are shown at  110 ,  112 ,  114  and  116 .  FIGS. 7A-7D and 8A-8D  show selective inflation of upper and lower airbags, respectively. 
       FIGS. 9A-12D  depict yet another embodiment that represents a modification of the embodiment of the embodiment of  FIGS. 5A-8D . This embodiment combines separate upper airbag and lower airbag spool valve controls with one inlet port and one exhaust port for each airbag. Thus, a second air inlet  120  is provided that connects with lower airbag  86  through internal port  108 . In  FIGS. 9A-9D  both valves are in their normal, unenergized position allowing pressurized air to enter and inflate both upper and lower airbags using separate connected sources of pressurized air (not shown). In  FIGS. 10A-10D , both valves are shifted, compressing the associated return spring and both bags are connected to exhaust ports causing them both to deflate. 
     In  FIGS. 11A-11D , the valve controlling the lower airbag is selectively energized with the valve controlling the upper airbag in the normal position thereby selectively inflating the upper airbag and collapsing the lower airbag. In  FIGS. 12A-12D  the converse is shown with the lower airbag  86  inflated and the upper airbag  84  collapsed. 
       FIGS. 13A-19C  depict a further embodiment of the airbag system of the invention in which each airbag is operated using two spool valves. The embodiment is illustrated with single and dual opposed mounted airbags. In  FIGS. 13A-13D  there is shown a version, generally at  200  having a single mounted airbag  202 . The system includes an intake spool valve  204  with solenoid  206  connected between airbag access port  208  and intake port  210 . The valve  204  is shown in its normal, unenergized state in which the connection to the intake port is closed and the return spring  212  extended as shown in  FIG. 13C .  FIG. 13D  illustrates the exhaust control with exhaust spool valve  214  controlled by solenoid  216  connecting airbag access port  208  with exhaust port  218 . The valve  214  is also shown in the normal, unenergized state with return spring  220  extended and the connection to exhaust port  218  is closed. In this configuration, the intake and exhaust ports may be located in the face of system base  222 , to which the airbag  202  is fixed, as shown. 
     As best shown in  FIG. 14B , the airbag system  200  is provided with a pressure sensor  230  in communication with the inside of the airbag  202  through a drilled access port  232 . The pressure sensor  230  is connected to a power supply through connector  234  and includes a signal connection at  236 . Solenoid  216  is shown with a power connection  238 , a ground connection  240  and a signal connection at  242 . 
     The pressure sensor  230  may be connected to a central processing unit or other well known device that in turn, sends a control signal to each solenoid associated with the airbag system. The solenoids then operate the intake and exhaust valve as needed to add or exhaust air to control the pressure inside the airbag based on a selected set point or range. The airbag system  200  can be individually controlled or ganged with other similar systems in any desired control scheme. 
     The pressure sensor is designed to continually monitor the airbag pressure. Thus, if a signal indicates that the pressure in the airbag has fallen below a desired minimum, this will be processed and a control signal will, in turn, initiate the addition of compressed air by operation of the intake valve until the set point is reached. Conversely, if the pressure is above a desired maximum pressure, a control signal will activate the exhaust valve which will release air until the desired pressure is again achieved. A control signal to exhaust all the air and allow the airbag to collapse may also be included. As indicated, a selected command pressure can be used for any number of airbag systems ganged together possibly performing similar or the same tasks. 
     In a preferred embodiment that includes both intake and exhaust spool valves, the valves are controlled to remain closed unless a pressure adjustment is being made. This is an option in the design. In addition to the use of internal pressure sensors, external load sensors (not shown) can be added to determine, and optionally control, the amount of external force exerted by the airbag system and that can be controlled within an acceptable tolerance of a selected command force using the valve system. 
       FIGS. 15-19C  depict an embodiment similar to that of  FIGS. 13A-14B  in a two-bag, double-acting configuration generally at  300 . The system includes back-to-back upper and lower airbags  302  and  304 , respectively. Each of the airbags is operated by a pair of spool valves including an intake and an exhaust valve and each bag is provided with a pressure sensor in the manner of single-bag embodiment  200 . 
     Thus, airbags  302  and  304  are both mounted on a central base  306 . Upper airbag  302  is provided with an intake valve  308  with solenoid operator  310  and return spring  312 . Openings for possible mechanical connection are shown at the free end of airbag  302  at  311  and  313 . The valve  308  connects an intake part  314  with an internal bag port  316 . An upper airbag pressure sensor  318 , as best seen in the rotated view of  FIG. 17B , is connected through drilled port  320  to communicate with the interior of airbag  302 . Airbag  302  further includes an exhaust spool valve  322  with solenoid operator  324  and return spring  326 . The valve connects an upper airbag exhaust portion  328  with upper internal airbag port  316 . 
     In a like manner, lower airbag  304  is provided with an intake spool valve  330  with solenoid operator  332  and selection spring  334 . Spool valve  330  connects a lower airbag intake port  336  with a lower airbag internal access port  338 . The lower airbag  304  also is provided with a pressure sensor  340  with access port  342 . Airbag  304  also includes an exhaust assembly including spool valve  344  with solenoid operator  346  and return spring  348 . That valve connects lower airbag exhaust port  350  with lower internal airbag port  338 . 
     As best shown in  FIG. 17B , pressure sensor  340  includes a power supply connector  352  and a signal connector  354  and pressure sensor  318  includes a power supply connector  356  and a signal connector  358 . As with the solenoids in embodiment  200 , each solenoid has a power connector, p, a ground connector, g, and a signal connector, s. 
       FIGS. 18A-18C  shows the embodiment  300  with both upper and lower intake valves closed and both exhaust valves opened to allow all the air to be exhausted and the airbags collapsed.  FIGS. 19A-19C  depict the system with both upper and lower intake valves energized and both exhaust valves in the normal unenergized, closed position allowing both airbags to be pressurized. Of course, both bags can be operated separately and at any desired set pressure selected. 
     In  FIGS. 20A-20C , there is shown an assembly which demonstrates the use of a pair of double-acting airbags in accordance with the invention in an arrangement in which the central base moves in accordance with airbag inflation/deflation and the outer ends of the airbags are constrained.  FIG. 20A  depicts a setup  400  including a pair of airbag assemblies  402  and  404  used to operate a clamping device on a band saw. Assembly  402  includes an upper airbag  406 , a lower airbag  408  and central base  410 . Airbag assembly  404  includes an upper airbag  412 , a lower airbag  414  and a central base  416 . Both airbag assemblies have dual air inlet ports for separate control of the upper and lower airbags, if desired, and two compressed air lines are shown at  418  and  420 . A common clamp assembly  422  is connected between central bases  410  and  416 . An outer constraining arrangement includes an upper aspect  424  and a lower aspect  426  that fix the outer ends of the airbags in back to back arrangement with the central bases  410  and  416 . 
     In  FIG. 20A , the arrangement is shown with the upper bags  406  and  412  inflated and the lower airbags  408  and  414  collapsed so that the connected assembly  422  is in a lowered state. Band saw  430  is shown in a lowered state and no work is depicted on table top  432 . In  FIG. 20B , both airbags in assemblies  402  and  404  are inflated and the assembly  422  has assumed a central location and is clamping work piece  434 . Finally, in view  20 C, lower airbags  408  and  414  are inflated and upper airbags  406  and  412  are collapsed so that assembly  422  is shown in a fully raised position so that work piece  434  can be removed and others inserted. 
     It will be appreciated that the central base of an airbag in an arrangement in which the outer ends are constrained and the central base is used as the moving element in a central system can be connected in any desired manner for the operation of an associated device. 
       FIGS. 21A-21D  depict an arrangement  500  in which a pair of back-to-back double-acting airbag assemblies control the elevation of an axle assembly. In that arrangement, the central bases remain fixed and the outer ends of the associated airbags move with airbag inflation/deflation. An axle assembly  502  includes wheel hubs  504  and  506  and an axle  502 . The axle  508  is attached to a pair of spaced pivoting parallelogram airbag operating arrangements  508  and  510  that are connected to axle  502  by assemblies  512  and  514 , respectively. As best seen in the sectional views, which depict one of the two identical opposed airbag operating arrangements, they include an upper airbag  520 , a lower airbag  522  and a central base  524 . The upper airbag operates against a member  526  which is attached to an upper pivoting member  528  that is pivotally attached between assembly  512  and a fixed member  530  at  532  and  534 , respectively. Similarly lower airbag  522  operates against a member  536  which is attached to a lower pivoting member  538  also pivotally connected between assembly  512  and fixed member  530  at  540  and  542 . Member  530  is fixed to channel member  544 . 
     In this example of use.  FIG. 21A  depicts the axle assembly in a raised position with the upper airbag inflated  520  and the lower airbag  522  collapsed as shown in section B-B of  FIG. 21B . Conversely,  FIGS. 21C and 21D  depict the axle assembly in a lowered position with the lower airbag  522  inflated and the upper airbag  520  collapsed. The central base  524  remains in a central position relative to member  530 . 
     Of course, as with the previous arrangement, back-to-back airbags can be used to operate any of numerous possible connected devices. 
     This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use embodiments of the example as required. However, it is to be understood that the invention can be carried out by specifically different devices and that various modifications can be accomplished without departing from the scope of the invention itself.