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An air compression apparatus has a frame, a tank, and a motor. A drive mechanism is operably connected to the motor and at least one piston assembly is operably connected to the drive mechanism and configured to move within a respective cylinder mounted to the frame. The piston assembly includes: (1

An air compression apparatus has a frame, a tank, and a motor. A drive mechanism is operably connected to the motor and at least one piston assembly is operably connected to the drive mechanism and configured to move within a respective cylinder mounted to the frame. The piston assembly includes: (1) a piston body; (2) a piston rod having a hollow bore connected at one end to the drive mechanism and at an opposite end to the piston body; and (3) a piston valve installed on the piston body. In use, upward travel of the piston body as caused by the drive mechanism acting through the piston rod opens the piston valve and allows ambient air to be drawn through the hollow bore into the cylinder, and downward travel of the piston body closes the piston valve so as to compress the air within the cylinder.

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What is claimed is: 1. An air compression apparatus having a frame and a tank and a motor mounted to the frame, the improvement comprising: a drive mechanism operably connected to the motor; at least one piston assembly operably connected to the drive mechanism and configured to move within a respe

What is claimed is: 1. An air compression apparatus having a frame and a tank and a motor mounted to the frame, the improvement comprising: a drive mechanism operably connected to the motor; at least one piston assembly operably connected to the drive mechanism and configured to move within a respective cylinder mounted to the frame, the piston assembly comprising: a piston body sealingly and slidably installed within the cylinder so as to form an upper chamber above the piston body and a lower chamber below the piston body, the piston body being further formed with a cavity in communication with at least the lower chamber; a piston rod having a hollow bore communicating between a drive end and a piston end, the drive end being connected to the drive mechanism such that the hollow bore is in communication with ambient air, the piston rod passing through the cylinder and the upper chamber so as to be connected at the opposite piston end to the piston body, the piston rod having at least one opening formed therein substantially at the piston end such that the hollow bore is in communication with the cavity; and a lower piston valve installed on the piston body so as to selectively seal the lower chamber from the cavity; and at least one air line connected between the cylinder and the tank for the passage of compressed air therethrough, whereby upward travel of the piston body as caused by the drive mechanism acting through the piston rod opens the lower piston valve and allows ambient air to be drawn through the hollow bore, the at least one opening, and the cavity into the lower chamber, and whereby downward travel of the piston body as caused by the drive mechanism acting through the piston rod closes the lower piston valve so as to compress the air within the lower chamber. 2. The apparatus of claim 1, wherein: the cylinder is pivotally mounted on a pivot pin; and the drive mechanism comprises: a flywheel rotatably mounted to the frame; a drive pulley installed on a drive shaft of the motor so as to be substantially coplanar with the flywheel; a drive belt engaging the drive pulley and the flywheel so that torque from the motor is transmitted to the flywheel through the drive belt; a crankpin mounted on the flywheel; and an intake block pivotally mounted on the crankpin so as to connect the piston rod to the flywheel, the intake block being formed with at least one passage for the communication of ambient air through the passage and into the hollow bore, whereby rotational movement of the flywheel translates into oscillating movement of the cylinder about the pivot pin and simultaneous axial displacement of the piston body within the cylinder. 3. The apparatus of claim 2, wherein: a pivot arm is pivotally mounted to the frame on a pivot shaft; the cylinder is mounted to the pivot arm on the pivot pin offset from the pivot shaft; and the drive mechanism further comprises a guide bar mounted to the pivot arm at a lower end, the guide bar having a slot formed at an opposite upper end such that the crankpin passes into the slot, whereby movement of the crankpin with rotation of the flywheel causes oscillating movement of the guide bar about the pivot shaft, translating into vertical and horizontal oscillating movement of the cylinder. 4. The apparatus of claim 3, wherein the slot is substantially linear. 5. The apparatus of claim 3, wherein the slot is substantially S-shaped. 6. The apparatus of claim 2, wherein: the flywheel is formed with an outer rim defining an elliptical profile having a major diameter and a minor diameter; and the drive mechanism further comprises at least one tensioner pulley substantially coplanar with the drive pulley and the flywheel and positioned so as to engage the drive belt. 7. The apparatus of claim 6, wherein: a first quadrant is defined as an arcuate segment of the flywheel between the major diameter and the minor diameter; and the crankpin is mounted on the flywheel within the first quadrant. 8. The apparatus of claim 7, wherein: a radially-outwardly projecting fastening plate is formed on the flywheel laterally offset from the drive belt; and the crankpin is mounted on the fastening plate. 9. The apparatus of claim 7, wherein: the flywheel further comprises: a hub rotatably installed on a flywheel shaft mounted to the frame substantially perpendicular to the flywheel; two or more radial spokes connecting the hub to the outer rim, two of the spokes being substantially aligned with the major diameter; and two or more masses symmetrically located within the outer rim substantially along the major diameter; and the crankpin is mounted on a spoke. 10. The apparatus of claim 2, wherein: the crankpin is formed with a free end extending beyond the intake block; and a roller bearing is installed on the free end so as to ride within the slot. 11. The apparatus of claim 2, wherein the cavity is in communication with the lower chamber and the upper chamber; the piston assembly further comprises an upper piston valve installed adjacent to the piston body so as to selectively seal the upper chamber from the cavity; and the air line is installed in the cylinder so as to communicate with both the upper chamber and the lower chamber, whereby upward travel of the piston body as caused by the drive mechanism acting through the piston rod closes the upper piston valve so as to compress the air within the upper chamber, and whereby downward travel of the piston body as caused by the drive mechanism acting through the piston rod opens the upper piston valve and allows ambient air to be drawn through the piston rod bore, the at least one opening, and the cavity into the upper chamber. 12. The apparatus of claim 11, wherein: an upper one-way valve is installed in the cylinder in communication with the upper chamber; a lower one-way valve is installed in the cylinder in communication with the lower chamber; and the air lines are connected to the upper and lower one-way valves, whereby the air compressed in the lower chamber when the piston body travels downward is forced through the lower one-way valve and into the air line leading to the tank, and whereby the air compressed in the upper chamber when the piston body travels upward is forced through the upper one-way valve and into the air line leading to the tank. 13. The apparatus of claim 11, wherein: the cylinder has an upper end formed by an upper cylinder wall and a lower end formed by a lower cylinder wall; an upper chamber plate is sealably installed within the cylinder offset from the upper cylinder wall so as to form therebetween an upper breathing chamber, the upper chamber plate being formed with at least one selectively sealable upper breathing hole communicating between the upper chamber and the upper breathing chamber; the upper cylinder wall and the upper chamber plate are formed with substantially axially aligned piston bores for the passage therethrough of the piston rod; a lower chamber plate is sealably installed within the cylinder offset from the lower cylinder wall so as to form therebetween a lower breathing chamber, the lower chamber plate being formed with at least one selectively sealable lower breathing hole communicating between the lower chamber and the lower breathing chamber; and the air lines are connected to the cylinder so as to communicate with the upper and lower breathing chambers, whereby the air compressed in the lower chamber when the piston body travels downward is selectively forced through the at least one lower breathing hole, into the lower breathing chamber, and then into the air line leading to the tank, and whereby the air compressed in the upper chamber when the piston body travels upward is selectively forced through the at least one upper breathing hole, into the upper breathing chamber, and then into the air line leading to the tank. 14. The apparatus of claim 1, wherein: the cylinder is rigidly installed on the frame; and the drive mechanism comprises: a chain drive mounted to the frame and having a driving sprocket and an idler sprocket in spaced apart relationship, the centers of the sprockets being along a centerline parallel to and offset from the axis of the cylinder, the chain drive further having a chain configured to engage the sprockets, whereby a drive shaft of the motor turns the driving sprocket so as to drive the chain about the sprockets; a guide rod mounted between offset attachment blocks installed on the frame, the guide rod being parallel to and offset from the centerline of the sprockets opposite the cylinder, the guide rod having a sliding bushing slidably operable thereon between the respective attachment blocks; a track arm rigidly mounted to the sliding bushing at an angle between zero and ninety degrees relative to the guide rod, the track arm having a slot formed therein; an intake block rigidly mounted on the track arm so as to connect the piston rod to the track arm, the intake block being formed with at least one passage for the communication of ambient air through the passage and into the hollow bore; and a cam follower mounted on the chain so as to project into and engage the slot, whereby movement of the chain about the sprockets translates into oscillating linear movement of the track arm and simultaneous axial displacement of the piston body within the cylinder as acted on by the piston rod rigidly mounted to the track arm through the intake block. 15. The apparatus of claim 1, wherein: a first cylinder and a second cylinder are rigidly installed on the frame in a substantially aligned offset arrangement, the first cylinder formed with a first lower cylinder wall and having a first piston body sealingly and slidably installed therein so as to form a first upper chamber above the first piston body and a first lower chamber below the first piston body, the first piston body being further formed with a first cavity in communication with the first lower chamber, the second cylinder formed with a second lower cylinder wall and having a second piston body sealingly and slidably installed therein so as to form a second upper chamber above the second piston body and a second lower chamber below the second piston body, the second piston body being further formed with a second cavity in communication with the second lower chamber; a first piston rod and a second piston rod are rigidly connected at respective adjacent ends to the drive mechanism, the first piston rod having a first hollow bore and at least one first breathing hole communicating between the first hollow bore and the ambient air, the first piston rod passing through the first cylinder and the first upper chamber so as to be connected at a first piston end opposite the drive mechanism to the first piston body, the first piston rod having at least one first opening formed therein such that the first hollow bore is in communication with the first cavity, the second piston rod having a second hollow bore and at least one second breathing hole communicating between the second hollow bore and the ambient air, the second piston rod passing through the second cylinder and the second upper chamber so as to be connected at a second piston end opposite the drive mechanism to the second piston body, the second piston rod having at least one second opening formed therein such that the second bore is in communication with the second cavity; at least one first escape passage is formed within the first cylinder so as to selectively communicate between the first upper chamber and the first lower chamber, the first escape passage having a first longitudinal length greater than the thickness of the first piston body; at least one second escape passage is formed within the second cylinder so as to selectively communicate between the second upper chamber and the second lower chamber, the second escape passage having a second longitudinal length greater than the thickness of the second piston body; a first lower piston valve is installed on the first piston body so as to selectively seal the first lower chamber from the first cavity; a second lower piston valve is installed on the second piston body so as to selectively seal the second lower chamber from the second cavity; a first one-way valve is installed in the first cylinder in fluid communication with the first upper chamber; a second one-way valve is installed in the second cylinder in fluid communication with the second upper chamber; and the air lines are connected to the first and second one-way valves, whereby movement of the drive mechanism in a first direction acts on the first piston rod to cause the first piston body to travel toward the first lower chamber, closing the first lower piston valve and compressing the air in the first lower chamber until the first piston body nears the first lower cylinder wall such that the at least one first escape passage is temporarily no longer sealed by the first piston body so as to allow the compressed air to pass from the first lower chamber through the at least one first escape passage and into the first upper chamber, and whereby movement of the drive mechanism in the first direction simultaneously acts on the second piston rod to cause the second piston body to travel toward the second upper chamber, further compressing the air in the second upper chamber and opening the second lower piston valve to allow ambient air to be drawn through the at least one second breathing hole, the second hollow bore, the at least one second opening, and the second cavity into the second lower chamber, and whereby movement of the drive mechanism in an opposite second direction acts on the first piston rod to cause the first piston body to travel toward the first upper chamber, further compressing the air in the first upper chamber and opening the first lower piston valve to allow ambient air to be drawn through the at least one first breathing hole, the first hollow bore, the at least one first opening, and the first cavity into the first lower chamber, and whereby movement of the drive mechanism in the second direction simultaneously acts on the second piston rod to cause the second piston body to travel toward the second lower chamber, closing the second lower piston valve and compressing the air in the second lower chamber until the second piston body nears the second lower cylinder wall such that the at least one second escape passage is temporarily no longer sealed by the second piston body so as to allow the compressed air to pass from the second lower chamber through the at least one second escape passage and into the second upper chamber. 16. The apparatus of claim 15, wherein the drive mechanism comprises: a piston rod mounting block mounted to the respective adjacent ends of the first and second piston rods so as to rigidly support the first and second piston rods in a substantially coaxial arrangement, the first and second breathing holes being positioned along the respective first and second piston rods so as to be clear of the piston rod mounting block; a yoke block rigidly mounted to the piston rod mounting block, the yoke block having an outwardly-opening yoke channel formed therein at an angle between zero and ninety degrees relative to the piston rod mounting block; a cam pulley mounted to the frame so as to rotate about a cam pulley shaft, the cam pulley having a cam follower projecting therefrom offset from the cam pulley shaft and oriented so as to extend into and engage the yoke channel; a drive pulley installed on a drive shaft of the motor so as to be substantially coplanar with the cam pulley; and a drive belt engaging the drive pulley and the cam pulley so that torque from the motor is transmitted to the cam pulley though the drive belt, whereby rotational movement of the cam pulley translates into oscillating linear movement of the piston rod mounting block and simultaneous axial displacement of the first and second piston bodies within the respective first and second cylinders as acted on by the respective first and second piston rods rigidly mounted within the piston rod mounting block. 17. The apparatus of claim 1, wherein: the cavity is in communication with the lower chamber and the upper chamber; the piston assembly further comprises an upper piston valve installed adjacent to the piston body so as to selectively seal the upper chamber from the cavity; and the air line is installed in the cylinder so as to communicate with both the upper chamber and the lower chamber, whereby upward travel of the piston body as caused by the drive mechanism acting through the piston rod closes the upper piston valve so as to compress the air within the upper chamber, and whereby downward travel of the piston body as caused by the drive mechanism acting through the piston rod opens the upper piston valve and allows ambient air to be drawn through the hollow bore, the at least one opening, and the cavity into the upper chamber. 18. The apparatus of claim 17, wherein: the piston body comprises an upper piston wall and an offset lower piston wall; the cavity comprises an upper piston bore formed in the upper piston wall in communication with a lower piston bore formed in the lower piston wall, the lower piston bore having an internal diameter substantially equivalent to the external diameter of the piston rod, the piston rod being seated within the lower piston bore so as to communicate therewith through the hollow bore, the upper piston bore having an internal diameter greater than the external diameter of the piston rod, the piston rod being formed with one or more cross-holes positioned therein so as to communicate between the hollow bore and the upper piston bore; an outwardly-opening annular channel is formed in the lower piston wall; a lower o-ring is seated within the annular channel; the lower piston valve comprises a lower valve disk movably mounted on the piston body substantially adjacent to the lower piston wall so as to selectively contact the o-ring and seal the lower piston bore; the upper piston bore is further formed with an outwardly-opening countersink; the upper piston valve comprises a collar slidably installed on the piston rod, the collar having a lower end substantially adjacent to the upper piston wall and formed with a shoulder; and an upper o-ring is seated against the shoulder so as to selectively contact the countersink and seal the upper piston bore. 19. The apparatus of claim 17, wherein: the cylinder has an upper end having a downwardly-facing upper surface intersected by an upper exit bore and a lower end having an upwardly-facing lower surface intersected by a lower exit bore, the upper exit bore being configured to selectively receive the upper piston valve and the lower exit bore being configured to selectively receive the lower piston valve; an upper release valve is installed within the piston body offset from the cavity so as to selectively communicate between the upper chamber and the lower chamber, the upper release valve having an upwardly-projecting, spring-biased upper contact pin configured to contact the upper surface after the piston body has traveled upwardly sufficiently to receive the upper piston valve within the upper exit bore, whereby displacement of the upper contact pin temporarily opens the upper release valve and allows compressed air to pass from the upper chamber through the upper release valve and into the lower chamber; and a lower release valve is installed within the piston body offset from the cavity and from the upper release valve so as to selectively communicate between the lower chamber and the upper chamber, the lower release valve having a downwardly-projecting, spring-biased lower contact pin configured to contact the lower surface after the piston body has traveled downwardly sufficiently to receive the lower piston valve within the lower exit bore, whereby displacement of the lower contact pin temporarily opens the lower release valve and allows compressed air to pass from the lower chamber through the lower release valve and into the upper chamber. 20. The apparatus of claim 17, wherein: the piston body comprises an upper piston wall and an offset lower piston wall; the cavity comprises an annular space substantially between the upper piston wall and the lower piston wall, one or more upper breathing holes formed in the upper piston wall so as to selectively communicate between the upper chamber and the annular space, and one or more lower breathing holes formed in the lower piston wall so as to selectively communicate between the lower chamber and the annular space, the piston rod being formed with one or more cross-holes positioned therein so as to communicate between the hollow bore and the annular space; an outwardly-opening lower annular channel is formed in the lower piston wall about each lower breathing hole; a lower o-ring is seated within each lower annular channel; the lower piston valve comprises a lower valve disk movably mounted on the piston body substantially adjacent to the lower piston wall so as to selectively contact each lower o-ring and seal the lower breathing holes; an outwardly-opening upper annular channel is formed in the upper piston wall about each upper breathing hole; an upper o-ring is seated within each upper annular channel; and the upper piston valve comprises an upper valve disk movably mounted on the piston body substantially adjacent to the upper piston wall so as to selectively contact each upper o-ring and seal the upper breathing holes. 21. The apparatus of claim 17, wherein: the piston body comprises an upper piston wall and an offset lower piston wall; the cavity comprises an annular space substantially between the upper piston wall and the lower piston wall, one or more upper breathing holes formed in the upper piston wall so as to selectively communicate between the upper chamber and the annular space, and one or more lower breathing holes formed in the lower piston wall so as to selectively communicate between the lower chamber and the annular space, the piston rod being formed with one or more cross-holes positioned therein so as to communicate between the hollow bore and the annular space; the lower piston valve comprises a lower valve disk movably mounted on the piston body substantially adjacent to the lower piston wall, the lower valve disk being formed with concentric upwardly-opening first and second annular channels, the channels being configured to define a seal area therebetween that is substantially adjacent to the lower breathing holes; a first lower o-ring is seated within the first annular channel and a second lower o-ring is seated within the second annular channel, the o-rings selectively contacting the lower piston wall so as to seal the lower breathing holes; an outwardly-opening upper annular channel is formed in the upper piston wall about each upper breathing hole; an upper o-ring is seated within each upper annular channel; and the lower piston valve comprises an upper valve disk movably mounted on the piston body substantially adjacent to the upper piston wall so as to selectively contact each upper o-ring and seal the upper breathing holes. 22. The apparatus of claim 21, wherein: a plug is installed within the hollow bore substantially at the piston end, the plug being formed with an outwardly-opening threaded hole; the lower valve disk is further formed with a clearance hole offset from and substantially concentric with the first and second annular channels; a fastening screw having a head and a threaded body projecting therefrom is passed through the clearance hole and threadably installed within the threaded hole; and a return spring is positioned about the threaded body between the head and the lower valve disk so as to bias the lower valve disk upwardly. 23. The apparatus of claim 1, wherein: the cylinder comprises an annular cylinder wall having an inside surface; the piston body comprises an upper piston wall, an offset lower piston wall, and an annular piston wall formed between the upper piston wall and the lower piston wall so as to define at least one radially-outwardly-opening circumferential piston ring channel; a piston ring is inserted within the piston ring channel so as to sealably and slidably contact the inside surface. 24. The apparatus of claim 23, wherein the piston ring is formed with a diagonal slit therethrough. 25. The apparatus of claim 23, wherein the piston ring is formed with one or more radially-outwardly-opening circumferential piston ring grooves. 26. The apparatus of claim 23, wherein: the annular piston wall is formed with a radially-outwardly-projecting circumferential rib so as to define an upper piston ring channel between the rib and the upper piston wall and a lower piston ring channel between the rib and the lower piston wall; an upper piston ring is inserted within the upper piston ring channel and a lower piston ring is inserted within the lower piston ring channel so as to cooperate to sealably and slidably contact the inside surface. 27. The apparatus of claim 23, wherein: the annular piston wall is formed with a radially-outwardly opening circumferential piston groove; and a piston o-ring is seated within the piston groove such that the piston ring inserted within the piston ring channel is radially-outwardly of the piston o-ring, whereby the piston ring is effectively sealed between the inside surface and the piston o-ring. 28. The apparatus of claim 23, wherein the annular piston wall is formed with multiple radially-inwardly-projecting longitudinal fins. 29. The apparatus of claim 1, wherein: the cylinder has an upper end formed by an upper cylinder wall and a lower end formed by a lower cylinder wall; an upper chamber plate is sealably installed within the cylinder offset from the upper cylinder wall so as to form therebetween an upper breathing chamber, the upper chamber plate being formed with at least one selectively sealable upper breathing hole communicating between the upper chamber and the upper breathing chamber; the upper cylinder wall and the upper chamber plate are formed with substantially axially aligned piston bores for the passage therethrough of the piston rod; a lower chamber plate is sealably installed within the cylinder offset from the lower cylinder wall so as to form therebetween a lower breathing chamber, the lower chamber plate being formed with at least one selectively sealable lower breathing hole communicating between the lower chamber and the lower breathing chamber; and the air lines are connected to the cylinder so as to communicate with the upper and lower breathing chambers, whereby the air compressed in the lower chamber when the piston body travels downward is selectively forced through the at least one lower breathing hole, into the lower breathing chamber, and then into the air line leading to the tank, and whereby the air compressed in the upper chamber when the piston body travels upward is selectively forced through the at least one upper breathing hole, into the upper breathing chamber, and then into the air line leading to the tank. 30. The apparatus of claim 29, wherein: an upwardly-opening upper annular channel is formed in the upper chamber plate about each upper breathing hole; an upper o-ring is seated within each upper annular channel; and an upper chamber disk is movably mounted within the upper breathing chamber substantially adjacent to the upper chamber plate so as to selectively contact the upper o-rings and seal the upper breathing holes. 31. The apparatus of claim 29, wherein: an upwardly-opening counterbore is formed substantially concentric with each upper breathing hole; an upwardly-opening upper annular channel is formed in the upper chamber plate substantially about the piston bores and connecting the upper breathing holes; an upper o-ring is seated within each counterbore; and a ball is movably inserted within each counterbore so as to selectively contact each upper o-ring and seal the upper breathing holes. 32. The apparatus of claim 29, wherein: a lower chamber disk is movably mounted within the lower breathing chamber substantially adjacent to the lower chamber plate, the lower chamber disk being formed with an upwardly-opening lower annular channel and being further formed with at least one lower chamber passage radially-outwardly offset from the lower annular channel; a lower o-ring is seated within the lower annular channel so as to selectively contact the lower chamber plate and seal the at least one lower breathing hole; and a return spring is positioned substantially between the lower chamber disk and the lower cylinder wall so as to bias the lower chamber disk upwardly. 33. The apparatus of claim 29, wherein: an upwardly-projecting support post is formed on the lower cylinder wall so as to extend into the lower breathing chamber; a upwardly-opening counterbore is formed in the lower chamber plate substantially concentric with the at least one lower breathing hole; a ball is movably inserted within the counterbore so as to selectively seal the at least one lower breathing hole; and a return spring is positioned about the support post between the ball and the lower cylinder wall so as to bias the ball upwardly. 34. The apparatus of claim 1, wherein: a first pillow block bearing is installed on the tank, the first pillow block bearing having a first through hole; a second pillow block bearing is installed on the tank offset from the first pillow block bearing, the second pillow block bearing having a second through hole substantially coaxial with the first through hole; the drive mechanism comprises: a flywheel shaft rotatably installed within the first and second through holes of the first and second pillow block bearings, the flywheel shaft having a flywheel end and an opposite drive arm end; a flywheel rigidly mounted to the flywheel shaft substantially at the flywheel end, the flywheel having a flywheel crankpin installed thereon; a drive arm rigidly mounted to the flywheel shaft substantially at the drive arm end, the drive arm having a drive arm crankpin installed thereon, the drive arm being mounted on the flywheel shaft such that the drive arm crankpin is out of phase with the flywheel crankpin; a drive pulley installed on a drive shaft of the motor so as to be substantially coplanar with the flywheel; a drive belt engaging the drive pulley and the flywheel so that rotation of the drive shaft is transmitted to the flywheel through the drive belt, whereby rotation of the flywheel is transmitted to rotation of the drive arm through the flywheel shaft; a flywheel intake block pivotally mounted on the flywheel crankpin; and a drive arm intake block pivotally mounted on the drive arm crankpin; a first cylinder and a second cylinder are pivotally installed on the frame in a substantially offset arrangement, the first cylinder having a first piston body sealingly and slidably installed therein so as to form a first upper chamber above the first piston body and a first lower chamber below the first piston body, the first piston body being further formed with a first cavity in communication with the first lower chamber, the second cylinder having a second piston body sealingly and slidably installed therein so as to form a second upper chamber above the second piston body and a second lower chamber below the second piston body, the second piston body being further formed with a second cavity in communication with the second lower chamber; a first piston rod being rigidly connected at a first drive end to the flywheel intake block and a second piston rod being rigidly connected at a second drive end to the drive arm intake block, the first piston rod having a first hollow bore configured to communicate with the ambient air through the flywheel intake block, the first piston rod passing though the first cylinder and the first upper chamber so as to be connected at a first piston end opposite the first drive end to the first piston body, the first piston rod having at least one first opening formed therein such that the first hollow bore is in communication with the first cavity, the second piston rod having a second hollow bore configured to communicate with the ambient air through the drive arm intake block, the second piston rod passing through the second cylinder and the second upper chamber so as to be connected at a second piston end opposite the second drive end to the second piston body, the second piston rod having at least one second opening formed therein such that the second bore is in communication with the second cavity; a first lower piston valve is installed on the first piston body so as to selectively seal the first lower chamber from the first cavity and a second lower piston valve is installed on the second piston body so as to selectively seal the second lower chamber from the second cavity; and the air lines are connected to the first and second cylinders so as to communicate with the first and second lower chambers, whereby rotation of the flywheel acts on the first piston rod through the flywheel crankpin and the flywheel intake block to cause the first piston body to travel within the first cylinder, alternately opening the first lower piston valve to pull ambient air through the first hollow bore and the first cavity into the first lower chamber and closing the first lower piston valve to compress the air in the first lower chamber, and whereby rotation of the flywheel simultaneously acts on the second piston rod through the flywheel shaft, the drive arm, the drive arm crankpin and the drive arm intake block to cause the second piston body to travel within the second cylinder, alternately opening the second lower piston valve to pull ambient air through the second hollow bore and the second cavity into the second lower chamber and closing the second lower piston valve to compress the air in the second lower chamber, the opening of the first lower piston valve being non-concurrent with the opening of the second lower piston valve and the closing of the first lower piston valve being non-concurrent with the closing of the second lower piston valve due to the flywheel crankpin and the drive arm crankpin being out of phase. 35. The apparatus of claim 1, wherein the piston assembly further comprises an acoustical sleeve installed within the hollow bore. 36. An air compression apparatus having a frame and a tank mounted to the frame, the improvement comprising: at least one piston assembly configured to move within a respective cylinder mounted to the frame, the piston assembly comprising: a piston body sealingly and slidably installed within the cylinder; a piston rod having a hollow bore communicating between a drive end and a piston end, the piston rod being connected to the piston body substantially at the piston end; and a means for selectively sealing the hollow bore substantially at the piston end; a means for driving the piston assembly within the cylinder such that the hollow bore is in communication with ambient air substantially at the drive end; and at least one air line connected between the cylinder and the tank, whereby upward travel of the piston body as caused by the driving means acting through the piston rod opens the sealing means and allows ambient air to be drawn through the hollow bore into the lower chamber, and whereby downward travel of the piston body as caused by the driving means acting through the piston rod closes the sealing means so as to compress the air within the lower chamber and pass the compressed air through the air line to the tank. 37. An air compression apparatus, comprising: a cylinder having a gland, an opposite end wall, and an annular wall therebetween defining an inside surface and a central axis; a piston body inserted within the cylinder in sliding engagement with the inside surface so as to define a first chamber between the piston body and the end wall and a second chamber between the piston body and the gland, the piston body being further formed with a cavity in communication with at least the first chamber; a piston rod passing though the gland and connected to the piston body, the piston rod having a hollow bore therein configured to communicate with ambient air outside the cylinder and configured to communicate with the cavity of the piston body inside the cylinder; a first inertial valve cooperating with the piston body to selectively seal the first chamber from the cavity; and a first exit valve installed in the cylinder so as to communicate with the first chamber, whereby movement of the piston body toward the gland opens the first inertial valve and allows ambient air to be drawn through the hollow bore and the cavity into the first chamber, and whereby movement of the piston body toward the end wall closes the first inertial valve so as to compress the air within the first chamber and pass the compressed air through the first exit valve. 38. The apparatus of claim 37, wherein: the cavity is in further communication with the second chamber; a second inertial valve cooperates with the piston body to selectively seal the second chamber from the cavity; and a second exit valve is installed in the cylinder so as to communicate with the second chamber, whereby movement of the piston body toward the end wall opens the second inertial valve and allows ambient air to be drawn through the hollow bore and the cavity into the second chamber, and whereby movement of the piston body toward the gland closes the second inertial valve so as to compress the air within the second chamber and pass the compressed air through the second exit valve. 39. The apparatus of claim 38, further comprising a means for driving the piston rod such that substantially all forces act on the piston body substantially along the central axis. 40. An air compression apparatus having a frame and a tank and a motor mounted to the frame, comprising: at least one piston assembly operably configured to move within a respective cylinder pivotally mounted to the frame, the piston assembly comprising: a piston body sealingly and slidably installed within the cylinder; a piston rod passing through the cylinder so as to be connected to the piston body; and at least one air inlet and at least one air outlet formed in the cylinder; a drive mechanism operably connected to the motor and to the piston assembly, the drive mechanism comprising: an elliptical flywheel rotatably mounted to the frame; a drive pulley installed on a drive shaft of the motor so as to be substantially coplanar with the flywheel; a drive belt engaging the drive pulley and the flywheel so that torque from the motor is transmitted to the flywheel through the drive belt; and a crankpin mounted on the flywheel and rotatably connected to the piston rod, whereby rotational movement of the flywheel translates into oscillating movement of the cylinder and simultaneous axial displacement of the piston body within the cylinder; and at least one air line connected between the cylinder and the tank for the passage of compressed air therethrough, whereby travel in a first direction of the piston body as caused by the drive mechanism acting through the piston rod draws ambient air through the air inlet into the cylinder, and whereby travel in a second direction of the piston body as caused by the drive mechanism acting through the piston rod compresses the air within the cylinder. 41. A method of compressing air, comprising the steps of: connecting a hollow piston rod to a piston body operating within a cylinder; introducing ambient air into the cylinder through the hollow piston rod; and moving the piston body within the cylinder to compress the air. 42. The method of claim 41, comprising the further steps of: opening a lower piston valve to allow ambient air to be drawn through the hollow piston rod into a lower chamber of the cylinder; and alternately closing the lower piston valve so as to compress the air within the lower chamber. 43. The method of claim 41, comprising the further steps of: opening a lower piston valve to allow ambient air to be drawn through the hollow piston rod into a lower chamber of the cylinder while closing an upper piston valve to compress the air within an upper chamber of the cylinder; and alternately closing the lower piston valve so as to compress the air within the lower chamber while opening the upper piston valve to allow ambient air to be drawn through the hollow piston rod into the upper chamber. 44. The method of claim 41, comprising the further step of oscillating the cylinder. 45. The method of claim 44, wherein the step of oscillating the cylinder comprises the further steps of: shifting the upper end of the cylinder arcuately about a pivot pin on which the base of the cylinder is mounted; and shifting the lower end of the cylinder arcuately about the pivot pin and arcuately about a pivot shaft offset from the pivot pin along a pivot arm. 46. A compression apparatus comprising: a piston body operating within a cylinder; a piston rod formed with a hollow bore and connected to the piston body such that the hollow bore is in selective communication with the cylinder; and a drive mechanism coupled to the piston rod through an intake block, whereby ambient air is selectively introduced into the cylinder through the intake block and the hollow bore for compression by the piston body as the piston body travels within the cylinder as caused by the drive mechanism acting through the piston rod.