Patent Publication Number: US-2007116585-A1

Title: Cam driven piston compressor apparatus

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates generally to the field of compression and storage of fluids and particularly to compression of gaseous matter. More specifically the present invention relates to a compressor apparatus including at least one cylinder and piston assembly including a cylinder having a cylinder head and a tubular cylinder side wall and a piston structure slidably retained within the tubular cylinder side wall, the cylinder head having an intake port fitted with an intake valve for passing fluid into the cylinder from a fluid source and an output port fitted with an output valve for passing fluid out of the cylinder such as to a fluid reservoir, valve operating means, a rotatable cam structure in the form of a cam wheel having a cam structure axle and radial cam protrusions in the form of cam arms positioned to periodically abut and displace the piston structure inwardly toward the cylinder head, and rotational drive means drivably connected to the rotatable cam wheel for rotatably driving the cam wheel and the cam arms about the cam wheel rotational axis, and a piston structure return means for displacing the piston structure outwardly away from the cylinder head subsequent to each piston structure inward displacement. The valve operating means opens the output valve and a cam arm abuts and displaces the piston structure toward the cylinder head, driving fluid within the cylinder out of the cylinder through the output port, and then the valve operating means closes the output valve and opens the intake valve and the piston structure return means displaces the piston structure outwardly, away from the cylinder head and the intake port, thereby drawing fluid through the intake port into the cylinder from the fluid source, in a periodically repeating cycle. The cylinder and piston assembly and cam wheel preferably are both fastened to an apparatus framework to position them in operational relation with each other. The apparatus framework preferably includes an apparatus housing enclosing at least the cam wheel. The intake port optionally is covered by an air filter retained within an air filter housing.  
      The number of cam arms provided on the cam structure determines the number of compression cycles the cylinder and piston assembly performs for each revolution of the cam structure, and is selected to meet the requirements of the given application. A flywheel preferably is provided adjacent the cam wheel and mounted to the cam wheel axle to provide smooth cam rotation. The piston structure preferably includes a piston connected to a piston rod. The rotational drive means preferably includes an electric drive motor connected to the cam structure with a belt and pulleys or other drive connection.  
      The number of cam arms on the cam structure preferably can be altered such that the volume of fluid compressed per cam structure revolution can be altered to accommodate any of a wide variety of applications. Another variation of the present compressor apparatus includes a plurality of cylinder and piston assemblies positioned and secured to the apparatus framework to extend radially and equidistantly from the cam structure to be operated by the cam arms in sequence. Yet another variation of the compression apparatus includes multiple cam structure and cylinder units. The cam structures preferably are cam wheels mounted on a common cam structure axle and thus driven by a common motor drive means.  
      2. Description of the Prior Art  
      There have long been compressors for compressing gaseous matter for storage or immediate use. These prior compressors typically have included a cylinder and piston combination driven by a motor or engine. A problem with these prior compressors has been that they can produce only one compression per motor or engine revolution, limiting compression to a specific rate which may or may not be suited for a given application. If a larger compression rate is needed, a different and larger compressor must be located.  
      It is thus an object of the present invention to provide a compressor apparatus which can compress a fluid at any of several different rates selectable for a given job or application, the apparatus including a cam structure rotatably driven by drive means and at least one cylinder and piston assembly driven through compression cycles by contact with at least one cam protrusion on the rotating cam structure.  
      It is another object of the present invention to provide such a compressor apparatus for which a specific desired rate of fluid compression can be selected by: selecting the number of cylinder and piston assembly compressions per revolution of motor drive means by altering the number of cam protrusions on the rotating cam structure, or by selecting the number of cylinder and piston assemblies operated with each revolution of the motor drive means, or by selecting the number of cam structure and corresponding cylinder and piston assemblies, or by altering all three variables as needed.  
      It is still another object of the present invention to provide such a compressor apparatus with which such selections can be made automatically by computer program operated electric switches.  
      It is finally an object of the present invention to provide such a compressor apparatus which is reliable, durable, requires less electricity to operate, and economical to manufacture.  
     SUMMARY OF THE INVENTION  
      The present invention accomplishes the above-stated objectives, as well as others, as may be determined by a fair reading and interpretation of the entire specification.  
      A compressor apparatus is provided for compressing fluids, including a compression vessel having a collapsible vessel internal space having an expanded size and a compressed size, the compression vessel having intake structure for passing fluid into the vessel internal space from a fluid source and output structure for passing fluid out of the vessel internal space; a rotatable cam structure having a cam structure rotational axis and at least one radial cam protrusion positioned to periodically abut the compression vessel and compress the vessel internal space; a rotational drive mechanism drivably connected to the rotatable cam structure for rotatably driving the cam structure and the cam protrusion about the cam structure rotational axis; and a compression vessel expansion mechanism for expanding the vessel internal space to its expanded size subsequent to each compression of the vessel internal space; so that compression of the vessel internal space drives fluid within the vessel internal space out of the vessel through the output structure, and then the compression vessel return mechanism expands the vessel internal space, thereby drawing fluid through the intake structure into the vessel internal space from the fluid source, in a repeating cycle.  
      The compression vessel preferably includes a cylinder and piston assembly having a cylinder interior and the vessel internal space comprise the cylinder interior.  
      A compressor apparatus for compressing fluids is further provided, including at least one cylinder and piston assembly including a cylinder having a cylinder head and a tubular cylinder side wall and a piston structure slidably retained within the cylinder, the cylinder having an intake port fitted with an intake valve for passing fluid into the cylinder from a fluid source and an output port fitted with an output valve for passing fluid out of the cylinder; a valve operating mechanism in operational relation with the intake valve and the output valve; a rotatable cam structure having a cam structure rotational axis and at least one radial cam protrusion positioned to periodically abut and displace the piston structure inwardly toward the cylinder head; a rotational drive mechanism drivably connected to the rotatable cam structure for rotatably driving the cam structure and the cam protrusion about the cam structure rotational axis; and a piston structure return mechanism for displacing the piston structure outwardly and away from the cylinder head subsequent to each piston structure inward displacement; so that the valve operating mechanism opens the output valve and the cam protrusion abuts and displaces the piston structure toward the cylinder head, driving fluid within the cylinder out of the cylinder through the output port, and then the valve operating mechanism closes the output valve and opens the intake valve and the piston structure return mechanism displaces the piston structure outwardly, away from the cylinder head and the intake port, thereby drawing fluid through the intake port into the cylinder from the fluid source, in a repeating cycle, as in any conventional cylinder and piston operation.  
      The cylinder and piston assembly and the cam structure preferably are both fastened to an apparatus framework to position the cylinder and piston assembly and the cam structure in operational relation with each other. The apparatus framework preferably includes an apparatus housing. The intake port preferably is covered by an air filter structure. The at least one cam protrusion preferably is at least one cam arm and the cam structure preferably includes a cam wheel having a cam wheel circumferential surface to which the at least one cam arm is mounted. The compressor apparatus preferably additionally includes a flywheel mounted to rotate in unison with the cam structure to provide smooth cam structure rotation.  
      The piston structure preferably includes a piston connected to a piston rod extending out of the cylinder opposite the cylinder head having a piston rod abutment end. The piston preferably is fitted with at least one piston ring seated in a circumferential piston ring groove to slide sealingly along the cylinder side wall. The cylinder preferably includes a cup-shaped cylinder bottom wall opposite the cylinder head with a central piston rod passing port for funneling blow-by oil to the piston rod so that the piston rod is lubricated by the oil and carries oil out of the cylinder with each cylinder and piston assembly cycle. The piston rod preferably includes at least one oil receiving depression for receiving and retaining oil to carry oil out of the cylinder through the piston rod passing port.  
      The rotational drive mechanism preferably includes an electric drive motor connected to the cam structure with a drive connection. The drive connection preferably includes a drive belt engaging a motor pulley mounted on the motor drive shaft and a cam structure pulley mounted on a cam structure axle.  
      The piston structure return mechanism preferably includes a piston rod biasing spring mounted to be compressed between a framework. The piston rod biasing spring preferably is a coil spring encircling the piston rod and having a progressively narrowing, conical configuration. The piston structure return mechanism preferably includes a piston return lever pivotally mounted on a lever fulcrum pin secured to the apparatus framework, having a return lever first end engaging the piston structure and a return lever second end positioned for periodic displacement by the at least one cam protrusion.  
      The cam protrusions may be fixed cams but preferably are selectively movable out of rotational alignment with the piston structure so that a desired number of the cam protrusions can be selected to displace the piston structure for each cam structure rotation; so that the volume of fluid compressed per cam structure rotation can be altered to accommodate requirements of any of a wide variety of applications. The where each cam arm includes an expanded mounting end which fits engagingly into any of several cam arm channels each having an outwardly narrowing arm engaging channel outward channel opening and extending laterally across the width of and spaced periodically around the cam wheel circumferential surface; so that each cam arm is slidably retained within a corresponding the cam arm channel. The cam wheel circumferential surface preferably is sufficiently wide and the cam arm channels therefore sufficiently long that one the cam arm can be slid to a first channel end of the given the cam arm channel and thus to a first side of the cam wheel circumferential surface to align with and abut the piston structure during cam wheel rotation, and slid to a second channel end and thus to a second side of the cam wheel circumferential surface to be out of registration with the piston structure during cam wheel rotation; so that a selected number of the cam arms can be slid to the first channel end to register with the piston structure as needed for a given apparatus application.  
      The cam arms preferably are each moved to one of the first side of the cam wheel circumferential surface and the second side of the cam wheel circumferential surface by electro magnets mounted adjacent opposing faces of the cam wheel and adjacent to the cam wheel circumferential surface; so that activation of either the electro magnet pulls each immediately adjacent cam arm to the adjacent the side of the cam wheel circumferential surface, and the given the electro magnet can be activated and deactivated as the cam wheel is rotated by the drive mechanism so that only selected cam arms are moved to a given side of the cam wheel circumferential surface to provide a desired number of cam arms in registration with the at least one cylinder and piston assembly associated with the cam wheel.  
      The compressor apparatus optionally includes several of the cylinder and piston assemblies positioned to extend radially and equidistantly from the cam structure, so that the at least one cam protrusion abuts and displaces each piston structure in sequence with each the cam structure rotation. The compressor apparatus optionally additionally or alternatively includes multiple cam structure and cylinder units mounted on a common axle and thus driven by a common motor drive mechanism, and individual clutches for each cam structure, so that only a selected number of the cam structures rotate with the drive mechanism.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Various other objects, advantages, and features of the invention will become apparent to those skilled in the art from the following discussion taken in conjunction with the following drawings, in which:  
       FIG. 1  is a side view of the a preferred embodiment of the compressor apparatus with the housing broken away to reveal the cam wheel, cam arms, and a cross-sectional view of the cylinder and piston assembly. Piston return means shown in this FIGURE include the return spring and return lever.  
       FIG. 2  is an end view of the compressor apparatus of  FIG. 1 .  
       FIG. 3  is a close-up cross-sectional side view of the cylinder and piston assembly of  FIG. 1 .  
       FIG. 4  is an end view of the apparatus of  FIG. 1  but adding the preferred sliding cam arm feature and showing some of the cam arms slid to a first channel ends to register with the piston structure and other cam arms slid to second channel ends to be out of registration with the piston structure. Opposing electro-magnets for moving the cam arms to selected first or second channel ends are also shown.  
       FIG. 5  is a side view of the cam wheel having the cam arm channels of  FIG. 4 .  
       FIG. 6  is an end view of the compressor apparatus of  FIG. 5 .  
       FIG. 7  is a side view of the cam wheel of  FIG. 5  additionally showing the preferred spring-loaded retaining protrusions for retaining the cam arms at their selected first or second channel ends.  
       FIG. 8  is an end view of the cam wheel of  FIG. 7 , showing the preferred central position of the retaining protrusions in the cam arm channels.  
       FIG. 9  is a view as in  FIG. 1 , except that a second cylinder and piston assembly is provided, to illustrate the option of providing two or more such assemblies on a given apparatus cam structure and cylinder unit.  
       FIG. 10  is an end view of the apparatus of  FIG. 4 , showing an optional second cam structure and cylinder unit, to illustrate the option of providing two or more such units in an individual compressor apparatus.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.  
      Reference is now made to the drawings, wherein like characteristics and features of the present invention shown in the various FIGURES are designated by the same reference numerals.  
     First Preferred Embodiment  
      Referring to  FIGS. 1-10 , a compressor apparatus  10  is disclosed including at least one cylinder and piston assembly  20  having a cylinder  22  having a cylinder head  24  and a tubular cylinder side wall  26  and a piston structure  40  slidably retained within the cylinder side wall  26 , the cylinder head  24  having an intake port  32  fitted with an intake valve  34  for passing fluid into the cylinder  22  from a fluid source FS and an output port  36  fitted with an output valve  38  for passing fluid out of the cylinder  22  such as to a fluid reservoir FR, valve operating means  50 , a rotatable cam structure  60  having a cam structure rotational axis A and at least one radial cam protrusion  62  positioned to periodically abut and displace the piston structure  40  inwardly toward the cylinder head  24  and rotational drive means  80  drivably connected to the rotatable cam structure  60  for rotatably driving the cam structure  60  and the cam protrusion  62  about the cam structure rotational axis A, and a piston structure return means  90  for displacing the piston structure  40  outwardly away from the cylinder head  24  subsequent to each piston structure  40  inward displacement. As a result, such that the valve operating means  50  opens the output valve  38  and the cam protrusion  62  abuts and displaces the piston structure  40  toward the cylinder head  24 , driving fluid within the cylinder  22  out of the cylinder  22  through the output port  36 , and then the valve operating means  50  closes the output valve  38  and opens the intake valve  34  and the piston structure return means  90  displaces the piston structure  40  outwardly, away from the cylinder head  24  and the intake port  32 , thereby drawing fluid through the intake port  32  into the cylinder  22  from the fluid source FS, in a periodically repeating cycle. Cylinder head  24  preferably is an integral part of the cylinder  22 , although it is contemplated that it be made removable for servicing. Cylinder side wall  26  preferably is surrounded by heat fins  26   a  to increase outer surface area and thus increase the dissipation of heat from compressing a fluid. The cylinder and piston assembly  20  and cam structure  60  preferably are both fastened to an apparatus framework  100  to position them in operational relation with each other. The apparatus framework  100  preferably includes an apparatus housing  110 . The intake port  32  optionally is covered by an air filter  122  retained within an air filter housing  124 .  
      The number of cam protrusions  62  provided on the cam structure  60  determines the number of compression cycles the cylinder and piston assembly  20  performs for each revolution of the cam structure  60 , and is selected to meet the requirements of the given job or application. The cam structure  60  preferably includes a cam wheel  70  having a cam wheel circumferential surface  72  to which one or more cam protrusions  62  are mounted. The cam protrusions  62  preferably each include a radially extending cam arm mounted to the wheel circumferential surface  72 . A flywheel  130  preferably is provided beside the cam wheel  70  and mounted to the cam wheel axle  74  to provide smooth cam structure  60  rotation.  
      The piston structure  40  preferably includes a piston  42  connected to a piston rod  44  extending out of the cylinder  22  opposite the cylinder head  24  and having a piston rod abutment end  44   a  fitted with a piston rod abutment end spring-loaded ball bearing  48  to ride over cam protrusions  62  with minimal friction and absorb the impact of abutting cam protrusions  62 . The piston rod  44  preferably is fixedly secured to the piston  42  to remain substantially parallel to the cylinder side wall  26 . The piston  42  preferably is fitted with conventional piston rings  42   a  seated in circumferential piston ring grooves  42   b  to slide sealingly along the cylinder side wall  26 . The cylinder  22  preferably has a cylinder bottom wall  28  opposite the cylinder head  24  with a central piston rod passing port  18 . Oil O lubricates the cylinder side wall  26  and is retained by the cylinder bottom wall  28 , which preferably is cup-shaped to gather the oil O and funnel it toward the piston rod  44 . Oil O thus deposited on the piston rod  44  enters and is retained by a longitudinal series of oil gathering depressions  46  in the piston rod  44 , preferably in the form of a series of notches  46 , and thus is carried by the piston rod  44  out of the cylinder  22 . This mechanism removes blow-by oil O accumulated in the cylinder  22  and at the same time lubricates the piston rod  44  so that it moves through the port  18  in the cylinder bottom wall  28  with minimal friction.  
      The rotational drive means  80  preferably includes an electric drive motor  82  connected to the cam structure  60  with a drive connection. The drive connection extends between the drive motor  82  and the cam structure  60  and preferably takes the form of a drive belt  84  engaging a motor pulley  86  mounted on the motor drive shaft  82   a  and a cam structure pulley  88  mounted on a cam structure axle  74 . The cam structure axle  74  preferably is mounted in bearings retained in axle retaining members  102  and  104  which form part of the apparatus framework  100 .  
      The piston structure return means  90  preferably is a piston rod biasing spring  92  mounted to be compressed between a framework outer brace  106  and a framework inner brace  108  and engaged by a return spring pin (not shown) passing through the piston rod  44 . The piston rod biasing spring  92  preferably is a coil spring encircling the piston rod  44  and preferably has a progressively narrowing, conical configuration.  
      Alternatively or additionally the piston structure return means  90  is a piston return lever  94  rotatably mounted on a lever fulcrum pin  96  secured to the apparatus framework  100 . See  FIG. 3 . A return lever first end  94   a  engages the piston structure  40  such as the piston rod  44  and a return lever second end  94   b  is periodically displaced by the cam protrusion  62  or cam protrusions  62 . Another alternative or additional piston return means  90  is a piston return solenoid coil  98  fitted around the piston rod  44  wired to a power source through a switch. When activated, piston return solenoid coil  98  rapidly drives the piston rod  44  and piston  42  away from the cylinder head  24 .  
      The number of cam protrusions  62  on the cam structure  60  preferably can be altered such that the volume of fluid compressed per cam structure  60  revolution can be altered to accommodate any of a wide variety of applications. Where the cam protrusions  62  are cam arms  62 , each cam arm  62  preferably has an expanded cam arm mounting end  64  which fits engagingly into any of several cam arm channels  76  having outwardly narrowing arm engaging channel outward ends  78  and extending laterally across the width of and spaced periodically around the cam wheel circumferential surface  72  such that each cam arm  62  is slidably retained within a corresponding cam arm channel  76 . See  FIGS. 4-6 . The cam wheel circumferential surface  72  preferably is sufficiently wide and the cam arm channels  76  therefore sufficiently long that a cam arm  62  can be slid to a first channel end  76   a  of the given cam arm channel  76  and thus to a first side of the cam wheel circumferential surface  72  to align and register with and abut the piston structure  40 , and slid to a second channel end  76   b  and thus to a second side of the cam wheel circumferential surface  72  to be out of registration with the piston structure  40  during cam structure  60  rotation. The cam arms  62  are retained against sliding out of their respective channels  76  by a retaining clip  77  at the outward-most portion of each channel end  76   a  and  76   b . See  FIG. 5 . As a result, a selected number of cam arms  62  can be slid into position to register with the piston structure  40  as needed for each given apparatus  10  application.  
      An outwardly biased spring-loaded retaining protrusion  66  is provided in the a recess in the middle of each cam arm channel end  76   a  and  76   b  to obstruct movement of and thus retain the cam arm  62  in the channel  76  at either the first or second channel end  76   a  or  76   b , respectively. See  FIGS. 7 and 8 . The retaining protrusions  66  are outwardly rounded, and when sufficient lateral force is applied to a given cam arm  62 , such as be an electro-magnet  140  described below, the retaining protrusion  66  is forced inwardly into its protrusion recess  66   a  by the cam arm  62  to become flush with the channel  76  bottom wall, permitting the cam arm  62  to move over the retaining protrusion  66  to the opposing channel end, and then the protrusion  66  is freed to spring outwardly to its initial retaining position.  
      The cam arms  62  preferably are moved to first or second cam wheel  70  sides by electro magnets  140  mounted to the apparatus framework  100  on opposing sides of the cam wheel  70  adjacent the cam wheel  70  circumferential perimeter. A small air gap is provided between the cam arms  62  and the electro magnets  140  so that cam arms  62  and electro magnets  140  never touch each other. Activation of either electro magnet  140  pulls each immediately adjacent cam arm  62  to the adjacent side of the cam wheel  70 . The given electro magnet  140  are activated and deactivated for only a fraction of a second as the cam wheel  70  is rotated by the drive motor  82  so that only selected cam arms  62  are moved to a given side of the cam wheel  70  to provide a desired number of cam arms  62  in registration with the at least one cylinder and piston assembly  20  associated with the given cam wheel  70 . Electric power delivered through a manual switch or a computer programmed controller (not shown) activates and deactivates one or the other electro magnet  140  as needed. Many other cam protrusion  62  moving mechanisms are contemplated, and the electro magnets are merely illustrative.  
      Another variation of the present compressor apparatus  10  includes a plurality of cylinder and piston assemblies  20  positioned and secured to the apparatus framework  100  to extend radially and equidistantly from the cam structure  60 . See  FIG. 9 . The rotating cam protrusion  62  or cam protrusions  62  abut and displace each piston structure  40  in sequence with each cam structure  60  rotation.  
      Yet another variation of the compression apparatus  10  includes multiple cam structure and cylinder units  200 . The cam structures  60  preferably are cam wheels  70  mounted on a common axle and thus driven by a common rotation drive means  180  in the form of a motor. See  FIG. 10 . Individual clutch means  182  are provided for each cam structure  60  so that only a selected number of the cam structures  60  rotate with the drive means  180 .  
      As an alternative to the one or more cylinder and piston structure assemblies  20 , a bellows or other collapsible vessel (not shown) may be provided.  
      While the invention has been described, disclosed, illustrated and shown in various terms or certain embodiments or modifications which it has assumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.