Abstract:
An apparatus is disclosed that includes a fluid inlet in fluid communication with a valve assembly, the valve assembly structured to selectively permit the flow of a motive fluid from the fluid inlet to a fluid driven motor, wherein the valve assembly further includes a first plunger including a plurality of axially extending fluid channels, wherein the plunger is selectively movable by an actuator in a manner such that as the plunger is displaced farther away from a closed position, the number of axially extending fluid channels placed in fluid communication with the fluid inlet increases, and wherein the axially extending fluid channels permit the flow of the motive fluid from the fluid inlet to the fluid driven motor.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Patent Application No. 61/679,038, filed Aug. 2, 2012, and is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to fluid driven motors, and more particularly, but not exclusively, to variable motor speed control of fluid driven machinery, including fluid driven tools. 
     BACKGROUND OF THE INVENTION 
     Speed control of fluid powered motors, specifically in the area of fluid driven machinery remains an area of interest. Many current designs provide maximum flow to the motor; and therefore, maximum motor speed immediately after a flow of fluid from an inlet valve is initiated. Therefore, further technological developments are desirable in this area. 
     BRIEF SUMMARY OF THE INVENTION 
     One embodiment of the present invention is a unique speed control device providing variable speed motor control for fluid driven motors. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for motor speed control for fluid powered machinery. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The description herein makes reference to the accompanying figures wherein like reference numerals refer to like parts throughout the several views, and wherein: 
         FIG. 1  depicts an embodiment of a fluid driven machine including a variable valve assembly. 
         FIGS. 2A-2B  depict an embodiment of a plunger including a plurality of axially disposed fluid channels. 
         FIG. 3  depicts an embodiment of a plunger assembly. 
         FIG. 4  depicts an embodiment of a variable valve assembly including multiple plungers. 
         FIGS. 5A-5C  depict embodiments of the variable valve assembly in various modes of operation. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     With reference to  FIG. 1 , one embodiment is disclosed of a fluid powered machine  100  including a housing  102  and a fluid driven motor  104 . It is contemplated that the fluid powered device  100  can include a variety of fluid powered devices such as pumps, presses, hoists, grain elevators, or any other fluid powered device  100 . In some embodiments, the fluid powered device  100  can be a power tool including, but not limited to a drill, ratchet, chisel, grinder, or the like. In one form, the fluid powered device  100  is a handheld pneumatic tool which includes a hand grip  120 . 
     The motive fluid  114  can be any fluid capable powering the fluid driven motor  104 . The motive fluid  114  can be a compressible gas. Air  114  can be utilized as the motive fluid  114 , which is received from a pressure source  116 . The pressure source  116  can include various compressors, pistons, pressurized tanks, or any other device which is capable of exerting or retaining pressure on the motive fluid  114 . In one form, the pressure source  116  is an oil free screw air compressor. 
     The fluid driven motor  104  can be any device which is capable of extracting energy from the motive fluid  114  and being driven thereby. The fluid driven motor  104  can be a piston, turbine, rotor, screw drive, or any other such device. The fluid driven motor  104  can be a turbine which converts the potential energy stored in the pressurized air  114  into rotational motion to be harnessed at a motor shaft output  122 . 
     A fluid inlet  106  allows the motive fluid  114  to flow into a valve assembly  108 . The fluid inlet  106  may include various flanges, fittings, etc., on an end opposite the valve assembly  108 , to provide ease of coupling with respect to the pressure source  116 . In some forms, the housing  102  can include a pressure chamber  118  to store a portion of motive fluid  114  to ensure consistent flow to the valve assembly  108 . 
     The valve assembly  108  is operated by an actuator  110 . The actuator  110  can take a variety of forms including, but not limited to, electronic or manual actuators such as linear actuators, hydraulic actuators, motor driven actuators, solenoids, or the like. The actuator  110  can receive an input from a location near the actuator, such as is illustrated in  FIG. 1 , or can receive an input signal from a distant location such as a push button (not shown) for use with a pneumatic hoist, as one non-limiting example. The actuator  110  can be a trigger  110  which provides a mechanical force to the valve assembly  108 . 
     The valve assembly  108  permits the selective release of the motive fluid  114  from the fluid inlet  106  to an inlet  112  of the fluid driven motor  104 . Referring to  FIGS. 2A and 2B , the valve assembly  108  includes at least one plunger  202 . The plunger  202  includes a plurality of axially extending fluid channels  204 ,  208 ,  212  located in a plunger body  214 . The axially extending fluid channels  204 ,  208 ,  212  can be grooves in the plunger body  214 , apertures extending within the plunger body  214  and having an intake  206 ,  210 , or can be any other passageway which permits the flow of fluid from an intake  206 ,  210  of the axially extending fluid channel  204  to an exit of the axially extending fluid channel  204 , wherein the exit is in flow communication with the fluid driven motor  104 . 
     Each of the plurality of axially extending fluid channels  204 ,  208 ,  212  includes a fluid intake  206 ,  210 ,  306 . The fluid intakes  206 ,  210 ,  306  are disposed axially in relation to each of the other fluid intakes  206 ,  210 ,  306 . An axis  220  is a reference axis for use in describing axial relationships as well as movement along an axis; however, the axial relationships and axial movements are not meant to be limited by axis  220 . In some forms, the fluid intakes  206 ,  210 ,  306  and corresponding axially extending channels  204 ,  208 ,  212  can be disposed circumferentially with relation to each other as is illustrated in  FIG. 2B . 
     Referring to  FIG. 3 , any number of axially extending fluid channels can be incorporated into the plunger body  214  depending upon the specific application, manufacturing capabilities, and any cost to benefit analysis associated therewith. As will be explained below, the number of axially extending fluid channels can determine the number of speeds at which the fluid driven motor  104  can operate.  FIG. 3  illustrates a plunger assembly  300  including five axially extending channels  204 ,  208 ,  212 ,  310 ,  314  and corresponding intakes  206 ,  210 ,  306 ,  308 ,  312 . In this non-limiting embodiment, the plunger body  214  is capable of providing five different fluid flows to the fluid driven motor  104 ; therefore, driving the fluid driven motor  104  at five different speeds. The plunger assembly  300  includes a plurality of sealing members  302  and  304  meant to segregate the inlet  106  from the inlet  112  of the fluid driven motor  104 . The sealing members  302  and  304  can be O-rings, gaskets, or any other devices capable of performing a sealing or semi-sealing function, depending on the specific application. In some forms, the sealing members  302  and/or  304  can be incorporated into various wall members or other housing structures of the valve assembly  108 , can be incorporated into one or more plungers, or the one or more plungers can themselves form the sealing members  302  and/or  304 . 
     As the plunger body  214  is displaced linearly by the actuator  110 , along the axis  202  in the direction illustrated at  320 , the first intake  206  of the axially extending channel  204  is placed in fluid communication with the fluid inlet  106 . As the plunger body  214  is displaced further in the direction illustrated by  320 , the second intake  210  is placed in fluid communication with the fluid inlet  106 . The motive fluid  114  can pass from the fluid inlet  106  through the fluid intakes  206  and  210 , traversing the axially extending fluid channels  204 ,  208 , and enter the fluid driven motor  104  through the inlet  112  of the fluid driven motor  104 . As illustrated, the remainder of the intakes  306 ,  308 , and  314  have not been placed in fluid communication with the fluid inlet  106  as the sealing member  302  prevents the motive fluid  114  from entering therein. Therefore, in this illustration, the motor  204  is only receiving motive fluid  114  from two of a potential five channels. 
     The valve assembly  108  can include more than one plunger.  FIG. 4  illustrates a cut away view  400  of the valve assembly  108  including a second plunger  404 . In some forms, the second plunger  404  can be located around the first plunger  202 . Upon full displacement of the first plunger  202 , the second plunger  404  can be displaced, providing a maximum motive fluid  114  flow. The second plunger  404  can additionally or alternatively contain a plurality of axially extending fluid channels through which the motive fluid  114  traverses upon the linear displacement of the second plunger  404 , as was discussed with reference to the first plunger  202 . In providing the second plunger  404  with a plurality of axially extending fluid channels, the number of total fluid driven motor  104  speeds can be increased. 
     Additionally,  FIG. 4  illustrates that a portion of the fluid inlet  106  and an inlet  402  of the valve assembly  108  can be disposed in a perpendicular or approximately perpendicular relationship. However, any configuration with relation to fluid inlet  106  and inlet  402  can be utilized depending upon the specific application and flow desired. 
     Referring now to  FIGS. 5A-5C , various illustrative modes of valve assembly  108  operation will be discussed. Referring to  FIG. 5A , the trigger  110  is not depressed and the plunger  202  is located at a first position  502 . The plungers  202  and  404 , acting as sealing member  302 , block the fluid intake  204 , and other fluid intakes (not shown), and effectively prevent the release of motive fluid  114  to the fluid driven motor  104  such that the fluid driven motor  104  is not powered. 
     Referring to  FIG. 5B , a manual force  506  is exerted on the trigger such that the first plunger  202  is moved from the first position  502  to a second position wherein the motive fluid  114 , received from the fluid inlet  106 , enters a first axially extending fluid channel  204 , and the motive fluid  114  is directed to the fluid driven motor  104 . As the trigger  110  continues to be depressed, the plunger  202  is directed to a third position where a second axially extending fluid channel  208  is also placed in flow communication with the fluid inlet  106 . In this second position, the motive fluid  114  received from the fluid inlet  106  traverses both the first and second axially extending fluid channels  204 ,  208  and is directed toward the fluid driven motor  104 . As the trigger  110  is depressed further, a third through n th  position can be reached, wherein n is the total number of channels disposed in the plunger body  214 . 
     As each position is reached, the axially extending fluid channel corresponding to the respective position is placed in flow communication with the fluid inlet  106 , and the motive fluid  114  traverses the respective axially extending fluid channel and is directed toward the fluid driven motor  104 . The total motive fluid  114  flow directed toward the fluid driven motor  104  is the combined total of the motive fluid  114  flows through each of the axially extending fluid channels  204 ,  208 , n th  which are in flow communication with the fluid inlet  106 . Therefore, the greater the number of axially extending fluid channels, the greater the number of speeds at which the fluid driven motor  104  can potentially be operated. 
     Referring to  FIG. 5C , the second plunger  404  can be axially displaced by the actuator  110 . When the motive fluid  114  is traversing all of the axially extending fluid channels in the first plunger  202 , continued depression  602  of the trigger  110  can result in linear movement of the second plunger  404  to an open position  604 . In various forms, the second plunger  404  can be displaced directly by the actuator  110 , or via relative motion of the first plunger  202  relative the second plunger  404 . For example, the second plunger  404  can be displaced by a protrusion  606  extending from the first plunger. The linear movement of the second plunger  404  can result in a fully open position of the valve assembly  108 , thereby permitting a maximum flow of the motive fluid  114  to the fluid driven motor  104 . As was aforementioned, the second plunger  404  can additionally have a plurality of axially extending channels, wherein displacement of the second plunger to a first through n th  position places a first through n th  axially extending channel in flow communication with the fluid inlet  106 , as was previously discussed with reference to the first plunger  202 . 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.