Abstract:
High frequency shock absorber/accelerator built in at any or both end of conventional air cylinder that includes piston moving axially inside cylinder body and sealed against inner surface of body by sealing structure. Cylinder piston rod protrudes outside thru cylinder front-end block Shock absorber/accelerator comprises piston with sealing structures moving axially in inner chamber, which communicates with outer chamber thru aperture(s). Air cylinder piston meets the protruded rod of the shock absorber/accelerator piston and starts to move it thus pushing volume of compressed air through provided aperture from inner chamber to outer chamber. Piston sealing structures seal air coming through the aperture thereby isolating compressed air in the outer chamber from the inner chamber. Compressed air coming through the open venting valve forces pistons to move in opposite direction. Then, shock absorber/accelerator aperture opens and compressed air rushes back from the outer to the inner chamber for powerful acceleration.

Description:
[0001]    This nonprovisional patent application is a continuation of pending U.S. provisional patent application No. 60/482,701 entitled Air Cylinder with High Frequency Shock Absorber and Accelerator filed Jun. 26, 2003 by Applicant Yevgeny Antonovksy. This nonprovisional patent application also claims priority from and completely incorporates by reference the previously filed U.S. patent application Ser. No. 09/978,938 entitled High frequency Shock Absorber and Accelerator by Yevgeny Antonovsky filed Oct. 17, 2001 and which has issued as U.S. Pat. No. 6,454,061 B1 on Sep. 24, 2003 as U.S. Pat. No. 6,612,410 B1 on Sep. 2, 2003. 
     
    
     
       SUMMARY  
         [0002]    The present invention is for an air (i.e. gas) cylinder, which combines conventional air cylinder and high frequency shock absorber/accelerator built-in at any one or both cylinder ends. Conventional air cylinder comprises cylinder body with piston moving axially inside of this body and sealed against body inner surface by sealing structure. Piston divides cylinder body in two chambers communicating with outside thru inlets (outlets). Cylinder piston rod protrudes outside through the front-end block, is sealed against this block by sealing structure and can be connected to the moving weight.  
           [0003]    A high frequency shock absorber/accelerator as described in U.S. Pat. No. 6,454,061 is mounted to any one or both cylinder ends.  
           [0004]    Shock absorber/accelerator comprises piston with sealing structures moving axially in inner chamber, which communicates with outer chamber thru aperture(s) or air line. Venting valve is mounted in shock absorber/accelerator rear end block. Shock absorber/accelerator piston rod protrudes through the front end block into adjacent air cylinder chamber. At a certain point of the stroke, air cylinder piston meets the protruded rod of the shock absorber/accelerator piston and starts to move it, thus pushing exact volume of compressed air from the shock absorber/accelerator&#39;s inner chamber to the outer chamber through provided aperture.  
           [0005]    During this process, air (gas) pressure in the shock absorber/accelerator chambers and resistance force applied to the air cylinder piston gradually increase, effectively decelerating moving weight.  
           [0006]    As shock absorber/accelerator piston moves further, the sealing structure on the piston seals flow of gas coming through the aperture thereby isolating the compressed air in outer chamber from the inner chamber.  
           [0007]    At the end of the stroke, shock absorber/accelerator piston actuates and opens the venting valve. The small amount of compressed air remaining in the inner chamber is pushed outside through this valve, leaving shock absorber/accelerator and air cylinder pistons loaded just by small return force generated by the valve spring.  
           [0008]    After directional control valve changes the direction of the compressed air flow, the compressed air is introduced through the venting valve into the shock absorber/accelerator&#39;s inner chamber and to the cylinder pressurized (formerly discharged) chamber through the inlet port. As a result, shock absorber/accelerator piston and air cylinder piston start to move simultaneously in the opposite direction.  
           [0009]    After a short travel shock, absorber/accelerator aperture opens and stored under high-pressure compressed air rushes back into the inner chamber, thus powerfully accelerating shock absorber/accelerator and air cylinder pistons with attached weight.  
           [0010]    After shock absorber/accelerator piston stops against the end block, acceleration phase is almost accomplished and the air cylinder piston with attached weight continues to move with low/moderate air pressure in the pressurized chamber until stroke is completed. Additional embodiments include different modifications of the outer chamber and venting valve and the air cylinder version in which shock absorber/accelerator piston and air cylinder piston are both integrated into one piston.  
         BACKGROUND OF THE INVENTION AND DISCUSSION OF PRIOR ART  
         [0011]    Air cylinders are used in large variety of different machinery, mechanisms and devices for executing reciprocating linear motion of the weight attached to the cylinder piston rod.  
           [0012]    To decelerate and stop moving weight without damage to the air cylinder and metal-to-metal banging, the following features are most commonly used: hydraulic shock absorbers, built-in resilient bumpers and air cushioning mechanisms, all of which have certain disadvantages.  
           [0013]    Hydraulic shock absorbers make air cylinder systems substantially more bulky and complicated. Due to the problem of overheating, they are not suitable for high speed/high frequency applications.  
           [0014]    Because oil cannot be compressed, there is significant mechanical impact when cylinder piston hits the hydraulic shock absorber rod at high velocity.  
           [0015]    The built-in resilient bumpers absorb only limited amount of energy and usually bounce back after deceleration is completed.  
           [0016]    The air cushioning mechanism&#39;s performance and problems associated with conventional air cylinders in general are discussed below:  
           [0017]    [0017]FIG. 1 illustrates conventional air cylinder system comprising air cylinder  10 , directional control valve  2 , flow control valves with adjustable orifice  3  and  5  and check valves  4  and  6  permitting air flow in one direction only.  
           [0018]    Air cylinder has air cushion mechanisms and consists of cylinder body  15  and piston  13  moving axially inside of this body; Piston is sealed against body inner surface by sealing structure  16  and is connected to the rod  14 . Cylinder body ends are closed by the front-end head  17  and rear end head  18  with cavities c and sealing structures  9 .  
           [0019]    Each end head has an inlet/outlet port and adjustable needle valve  11  or  12 .  
           [0020]    Piston rod  14  protrudes through the front-end head and is supported by bearing  20  and is sealed off from the atmosphere by a sealing structure  19 .  
           [0021]    When directional control valve  2  is in the position shown, compressed air from compressed air source  1  through directional valve  2 , check valve  4 , inlet port e of front end head and cavity c enters into cylinder pressurized chamber A with the pressure P 1  and starts to accelerate piston  13 , rod  14  and attached weight in the direction of the arrow.  
           [0022]    Air from cylinder chamber B through rear end head cavity c, outlet port d, flow control valve  5  and directional valve  2  is being discharged to the atmosphere.  
           [0023]    As piston velocity increases, the flow control valve  5  resistance and subsequently chamber B air pressure P 2  also increase.  
           [0024]    As a result (see FIG. 1/ 3 ), at certain point of the piston stroke (so called equilibrium point) force of the air pressure P 1  in chamber A applied to the piston in arrow direction becomes about equal to the friction force and force created by air pressure P 2  in chamber B, acting in opposite direction.  
           [0025]    From this point on, the piston moves with approximately uniform velocity (so called “flow controlled” motion) up to the moment when rear cushion spear  7  engages with sealing structure  9  (see FIG. 1/ 2 ).  
           [0026]    After this, cavity c gets closed and compressed air from chamber B could be discharged into the atmosphere through the needle valve  11  orifice b only, with much higher resistance.  
           [0027]    This leads to the surge of pressure P 2 , and, as a result, piston resistance force in chamber B becomes bigger than piston driving force in chamber A, which provides moving weight deceleration.  
           [0028]    However the air cushion mechanism as described above, has a substantial problem:  
           [0029]    The resistance of needle valve  11  orifice b also depends on piston velocity.  
           [0030]    As piston velocity decreases along the deceleration path of the stroke, orifice b resistance and pressure P 2  also decrease which seriously affects mechanism stoppage ability. In another words cushion mechanism deceleration force is not uniform and after initial peak surge diminishes very rapidly significantly limiting deceleration capacity.  
           [0031]    In some cases (limited intake volume of compressed air or prolonged acceleration) pressure P 2  could be much lower than P 1 , which will make air cushion mechanism even less effective.  
           [0032]    In addition to the problem with air cushion mechanism, practically any conventional air cylinder system has more design-inherited problems:  
           [0033]    100% of compressed air volume involved in producing air cylinder piston reciprocating motion is being discharged to the atmosphere, resulting in big energy (money) loss.  
           [0034]    In many applications, after piston acceleration is completed and maximum velocity is reached, piston continues to move under high pressure in pressurized and discharged chambers, thus uselessly consuming extra volume of compressed air. This results in additional energy (money) loss and a large driving (propelling) force. Absorbing propelling force energy takes significant share of total absorbed energy which otherwise can be used more productively.  
           [0035]    Air cylinder&#39;s ability to accelerate moving weight usually substantially exceeds cylinder stoppage capacity. To make them about equal, cylinder&#39;s accelerating ability is very often unnecessary reduced (by adjusting flow control valve on discharge line). This prevents cylinder from being used to its full potential. With higher stoppage capacity, the same air cylinder could have worked in much more powerful acceleration mode.  
           [0036]    To start each and every piston stroke, air pressure in pressurized chamber must be built up again and again from atmospheric to the operational level. This is achieved by throttling all compressed air volume through the orifice of directional control valve, which, in turn, delays acceleration, increases stroke completion time and subsequently reduces cycling frequency thus making the cylinder less suitable for high speed, high cycling applications.  
         SUMMARY OF THE INVENTION  
         [0037]    Powerful air (gas) cylinder with built-in shock absorber/accelerator, which—compared to conventional air cylinder—can move heavier weight with higher velocity/frequency cycling, consuming, at the same time, much less of the compressed air.  
           [0038]    Air (gas) cylinder with built-in shock absorber/accelerator is developed in two versions.  
           [0039]    Version 1.  
           [0040]    Air (gas) cylinder combines conventional air cylinder and high frequency shock absorber/accelerator built in at any or both cylinder ends.  
           [0041]    Conventional air cylinder consists of piston moving axially inside cylinder body and sealed against inner surface of the body by sealing structure.  
           [0042]    Cylinder piston rod protrudes outside thru cylinder front-end block and can be connected to the moving weight.  
           [0043]    The high frequency shock absorber/accelerator covered by Applicant&#39;s U.S. Pat. No. 6,454,061 is mounted to any one or both cylinder ends.  
           [0044]    Shock absorber/accelerator comprises piston with sealing structures moving axially in inner chamber, which communicates with outer chamber thru aperture(s) or air line. Shock absorber /accelerator is provided with venting valve mounted in rear end block and with piston rod protruding thru front end block to the adjacent chamber of the air cylinder.  
           [0045]    Compressed air is introduced to the air cylinder and shock absorber/accelerator by two individual air supply lines with independent adjustment of air pressure (usually low or moderate to the cylinder and high to the shock absorber/accelerator).  
           [0046]    At certain point of the stroke, air cylinder piston meets the protruded rod of the shock absorber/accelerator piston and starts to move it thus pushing exact volume of compressed air through provided aperture from shock absorber/accelerators inner chamber to the outer chamber.  
           [0047]    Gradually increasing resistance force created during this process effectively decelerates moving weight.  
           [0048]    As shock absorber/accelerator piston moves further, piston sealing structures seal the air coming through the aperture thereby isolating compressed air in the outer chamber from the inner chamber. Pressure of the compressed air stored in the outer chamber can be significantly higher than in air supply line.  
           [0049]    At the end of the stroke, shock absorber/accelerator piston actuates venting valve, which allows small amount of compressed air remaining in the inner chamber to be vented out.  
           [0050]    Deceleration process is accomplished and shock absorber/accelerator and air cylinder pistons are brought to stop. Small return force generated by the venting valve spring is still applied to the pistons.  
           [0051]    As a directional control valve changes direction of the compressed air flow, the compressed air is introduced to the shock absorber/accelerator&#39;s inner chamber through the open venting valve and through the inlet port to the pressurized (formerly discharged) chamber of the cylinder. This forces shock absorber/accelerator and air cylinder pistons to move simultaneously in opposite direction.  
           [0052]    After a short piston travel, shock absorber/accelerator aperture opens and stored under high pressure compressed air rushes back from the outer to the inner chamber, powerfully accelerating shock absorber/accelerator and air cylinder pistons with attached weight.  
           [0053]    Shock absorber/accelerator piston and air cylinder piston move together until shock absorber/accelerator stops against the end block.  
           [0054]    At this point acceleration process is almost complete and air cylinder piston continues its motion under low/moderate air pressure until the end of the cylinder stroke.  
           [0055]    Version 2.  
           [0056]    Air cylinder, with built-in shock absorber/accelerator, (patented by U.S. Pat. No. 6,454,061) at any one or both ends  
           [0057]    Cylinder has a piston axially movable inside of the cylinder body and connected to the rod protruding outside of the cylinder.  
           [0058]    The same piston works also as a compressed air pushing element for integrated shock absorbers/accelerators.  
           [0059]    The common air supply line introduces compressed air to the air cylinder and shock absorber accelerator.  
           [0060]    Cylinder body has two apertures for each shock absorber/accelerator. One of the apertures communicates with shock absorber/accelerator outer chamber and second one with air cylinder inlet/outlet port adjacent to the shock absorber/accelerator.  
           [0061]    Air cylinder piston has two sets of sealing structures with the same pitch as apertures, which allows sealing both apertures at the same time at the very end of the piston stroke.  
           [0062]    Compressed air is introduced to the pressurized chamber and forces air piston to move.  
           [0063]    As piston velocity increases, the discharged line flow control valve resistance and subsequently air pressure in discharged chamber also increases until forces applied to the cylinder piston from both sides become almost equal. Then, the piston moves with uniform velocity, pushing compressed air from discharged chamber to the atmosphere until air cylinder outlet port on discharged line remains open.  
           [0064]    At a certain point of the stroke, the first set of piston seal structures closes aperture communicating with discharging outlet port and prevents compressed air remaining in discharged chamber from exhausting through this port.  
           [0065]    From this point on, compressed air is pushed from the cylinder discharged chamber through the still open second aperture to the outer chamber.  
           [0066]    Gradually increasing resistance force, created during this process effectively decelerates moving weight.  
           [0067]    Piston moves further and second aperture connected with outer chamber gets closed thus isolating compressed air in outer chamber from discharged cylinder chamber.  
           [0068]    Compressed air pressure in the outer chamber could be significantly higher than the supply line pressure.  
           [0069]    At the end of the stroke, piston actuates venting valve and the remaining compressed air is pushed outside.  
           [0070]    After that, deceleration, in general, is completed and piston stops against cylinder end block.  
           [0071]    Small return force generated by valve spring remains applied to the piston.  
           [0072]    As direction control valve changes the direction of the air flow, compressed air is introduced through the open venting valve to the pressurized (formerly discharged) cylinder chamber, forcing piston to move in the opposite direction.  
           [0073]    After a short travel, outer chamber aperture opens and compressed air enters pressurized cylinder chamber powerfully accelerating piston with connected weight.  
           [0074]    Piston moves further and the second aperture gets open permitting compressed air from the supply line to be introduced into the pressurized chamber of the cylinder.  
           [0075]    At this point, air pressure in the outer chamber and pressurized chamber of the cylinder are reduced and equalized to the air supply line pressure and piston continues to move under reduced air pressure until stroke is completed.  
         OBJECTS AND ADVANTAGES  
         [0076]    The following are some of the important objects and advantages of the present invention:  
           [0077]    (1) to provide an air cylinder that can move much heavier weight with the same or higher velocity and cycling frequency than comparably sized conventional air cylinder.  
           [0078]    (2) to provide an air cylinder which consumes much less of compressed air while moving the same or bigger weight with the same or higher velocity as comparably sized conventional air cylinder  
           [0079]    (3) to provide an air cylinder with large energy (money) savings compare to conventional air cylinder in the same size category under identical circumstances.  
           [0080]    (4) to provide an air cylinder which automatically switches from high to low air pressure in pressurized cylinder chamber and, as a result, to low driving (propelling) force after piston acceleration is completed.  
           [0081]    (5) to provide an air cylinder in which significant part of compressed air is stored in a closed outer chamber during the retraction stroke deceleration and is being used timely to accelerate moving weight during extension stroke.  
           [0082]    (6) to provide an air cylinder with outer chamber(s) designed and located in such a way that stored compressed air is introduced to the pressurized cylinder chamber by bypassing directional control valve and with minimum resistance, thus avoiding time and energy consuming throttling.  
           [0083]    (7) to provide an air cylinder which safely executes stroke in any direction substantially faster than comparably sized conventional air cylinder carrying the same (or even smaller) weight.  
           [0084]    (8) to provide an air cylinder which delivers higher cycling frequency (number of strokes per minute) than conventional air cylinder under identical circumstances, while consuming much less of compressed air.  
           [0085]    (9) to provide an air cylinder with variety of embodiments (complexity level, outer chamber and venting valve modifications) to satisfy broad range of applications.  
           [0086]    (10) to provide an air cylinder simple enough to be paid off in short time due to inherited ability to save energy/money, and  
           [0087]    (11) to provide an air cylinder that incorporates a shock absorber and accelerator wherein the shock absorber and accelerator is in accordance with that disclosed in U.S. Pat. No. 6,454,061. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0088]    [0088]FIG. 1 PRIOR ART  
         [0089]    [0089]FIG. 1/ 2  Partial longitudinal cross section of air cylinder at a moment when cushion begins.  
         [0090]    [0090]FIG. 1/ 3  Graph illustrating air cylinder piston velocity vs. piston stroke.  
         [0091]    THE PRESENT INVENTION (remaining views relate to the present invention)  
         [0092]    [0092]FIG. 2 Longitudinal cross sectional and front view of air cylinder of the present invention with shock absorber/accelerator mounted to the cylinder rear end.  
         [0093]    [0093]FIG. 3A Longitudinal cross-sectional view of the present invention to illustrate how FIG. 2 air cylinder works during retraction stroke.  
         [0094]    [0094]FIG. 3B Longitudinal cross-sectional view of the present invention to illustrate how FIG. 2 air cylinder works during extension stroke.  
         [0095]    [0095]FIG. 4 Longitudinal cross sectional view and front view of double wall air cylinder of the present invention with shock absorber/accelerator mounted to the air cylinder rear end  
         [0096]    [0096]FIG. 5A Longitudinal cross-sectional view of present invention to illustrate how FIG. 4 air cylinder works during retraction stroke  
         [0097]    [0097]FIG. 5B Longitudinal view of the air cylinder of the present invention to illustrate how FIG. 4 air cylinder works during extension stroke.  
         [0098]    [0098]FIG. 6 Longitudinal cross-section and front view of double wall air cylinder with two shock absorbers/accelerators mounted on the both ends of air cylinder.  
         [0099]    [0099]FIG. 6A Illustrates by longitudinal view how FIG. 6 air cylinder works during retraction stroke.  
         [0100]    [0100]FIG. 7 Longitudinal cross section and front view of air cylinder with shock absorber/accelerator mounted to the rear end of the air cylinder and external accumulator serving as shock absorber/accelerator outer chamber, mounted outside of the cylinder and connected to shock absorber/accelerator by air line.  
         [0101]    [0101]FIG. 8 Longitudinal cross section and front view of air cylinder with shock absorber/accelerator mounted to the cylinder rear end and with external accumulator mounted directly to the shock absorber/accelerator frame.  
         [0102]    [0102]FIG. 9 Longitudinal cross-section and a front view of an air cylinder with the integrated rear end shock absorber/accelerator, with outer chamber surrounding air cylinder body.  
         [0103]    [0103]FIG. 9A Longitudinal cross-section and front view of air cylinder with integrated shock absorbers/accelerators at both ends with outer chambers surrounding air cylinder body.  
         [0104]    [0104]FIG. 10 Illustrates how FIG. 9 air cylinder works during retraction stroke  
         [0105]    [0105]FIG. 11 Illustrates how FIG. 9 air cylinder works during extension stroke  
         [0106]    [0106]FIG. 12 Longitudinal cross-section and front view of air cylinder with shock absorbers/accelerators integrated at both ends and with external accumulator serving as outer chamber for both shock absorbers/accelerators and mounted directly on air cylinder body parallel to the cylinder axis.  
         [0107]    [0107]FIG. 13 Longitudinal cross section and front view of air cylinder with shock absorbers/accelerators integrated at both ends and an external accumulator serving as outer chamber for shock absorbers/accelerators mounted outside of air cylinder and connected to the shock absorbers/accelerators by air lines.  
         [0108]    [0108]FIG. 14 Longitudinal cross section and front view of air cylinder with shock absorbers/accelerators integrated at both ends with two separate external accumulators serving as outer chamber to shock absorbers/accelerators and mounted directly to cylinder body perpendicular to the cylinder axis.  
         [0109]    [0109]FIG. 15 Performance graphs comparing conventional air cylinder with air cushion mechanisms and air cylinders with mounted shock absorbers/accelerators and it applies to the version  1  air cylinder depicted in FIGS. 2 through 8.  
         [0110]    [0110]FIG. 15A Performance graphs comparing conventional air cylinder with cushion mechanisms and air cylinders with integrated shock absorbers/accelerators and it applies to the version  2  air cylinder depicted in FIGS. 9 through 14. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0111]    Note that FIG. 2 through FIG. 8 illustrate air cylinders with mounted shock absorbers/accelerators having their own piston and separate compressed air replenish line whereas FIG. 9 through FIG. 14 illustrate air cylinders with integrated shock absorbers/accelerators having common piston and compressed air supply line with air cylinder (based on U.S. Pat. No. 6,454,061).  
         [0112]    [0112]FIG. 2 depicts air cylinder  10  with self-contained shock absorber/accelerator  20  mounted to the rear end of an air cylinder.  
         [0113]    Air cylinder comprises cylinder body  15 , piston  12  with rod  11 , front-end head  16  with front inlet/outlet  13  or front port  13  and rear end head  17  with rear inlet/outlet  14  or rear port  14 . For convenience, the term “inlet/outlet” is also called port. The air cylinder is also called gas cylinder. The term cylinder gas is used to refer to the gas, typically air, that goes in and out of the ports of the air or gas cylinder.  
         [0114]    Cylinder piston  12  moves with reciprocating motion inside of cylinder body  15 . Cylinder sealing structures  18  and  18 A seal piston  12  against cylinder body  15  and rod  11  against front-end head  16 .  
         [0115]    Shock absorber/accelerator consists of piston  34  with sealing structures  36 , rod  35  connected to the piston, tubes  38  and  39  defining boundaries of inner  30  and outer  31  chambers, front  40  and rear  41  blocks closing ends of inner and outer chambers and spring loaded venting spool valve  32  with actuating pin  42  protruding to the inner chamber.  
         [0116]    Inner and outer chamber are connected thru apertures  33 .  
         [0117]    Shock absorber/accelerator piston rod  35  protrudes into adjacent chamber of the cylinder and sealed by sealing structure  18 B.  
         [0118]    Air cylinder system has two independent compressed air supply lines L 1  and L 2 .  
         [0119]    Air pressure in these lines can be independently adjusted for variety of applications.  
         [0120]    Line L 1  provides air cylinder piston reciprocating movement and usually operates under low or moderate air pressure.  
         [0121]    Line L 1  comprises pressure regulator  7 , two position directional control valve  2 , flow control valves  3  and  5  and check valves  4  and  6 .  
         [0122]    Line L 2  delivers compressed air to the shock absorber/accelerator chambers and usually operates under high air pressure.  
         [0123]    Line L 2  comprises pressure regulator  8 , two position directional control valve  2 A and check valve  9 .  
         [0124]    When directional control valve  2 A is switched to the second position (not shown on the drawing) line L 2  is blocked and inner and outer shock absorber accelerator chambers are connected to the atmosphere.  
         [0125]    [0125]FIG. 2 air cylinder operation is described in details in FIG. 3A and FIG. 3B FIG. 3A (retraction stroke)  
         [0126]    [0126]FIG. 3A/ 1  Compressed air from supply line L 1  thru pressure regulator  7 , directional control valve  2 , check valve  4 , and inlet port  13  introduced to the air cylinder pressurized chamber A, and pushes piston  12  with rod  11  in arrow direction.  
         [0127]    Compressed air from line L 2  thru pressure regulator  8 , directional control valve  2 A and check valve  9  is introduced to outer chamber  31  and thru aperture  33  to inner chamber  30  of shock absorber/accelerator.  
         [0128]    At some point of the retraction stroke air cylinder piston  12  meets shock absorber/accelerator piston  34  rod  35  and starts pushing it in arrow direction, compressing thru aperture  33  air stored under pressure in chamber  30  into outer chamber  31 .  
         [0129]    Gradually increasing resistance force, created during this process, effectively decelerates moving weight.  
         [0130]    Air from air cylinder chamber B thru outlet  14 , flow control valve  5  and directional valve  2  is vented to the atmosphere.  
         [0131]    Pressure of compressed air stored in outer chamber  31  could be significantly higher than pressure in air supply line L 2 .  
         [0132]    [0132]FIG. 3A/ 2  Piston  12  moves further and sealing structures  36  seal air coming thru aperture  33  thereby isolating compressed air in the outer chamber  31  from the inner chamber  30 .  
         [0133]    At the end of the stroke piston  34  thru pin  42  pushes spool valve to the left thus opening flow control valve  5 A of passage a-b-c-d-e for venting of remaining in the inner chamber  30  compressed air thru valve  2  to the atmosphere.  
         [0134]    Flow control valve  5 A can be also used for final adjustment of the piston velocity at the very end of the stroke.  
         [0135]    After retraction stroke is fully completed the piston is located in “home position”, compressed air is stored in outer chamber  31  and inner chamber  30  thru spool valve  32 , outlet e and directional control valve  2  is connected to the atmosphere.  
         [0136]    Small returned force is applied to piston  34  (and  12 ) by compressed spring  37 .  
         [0137]    [0137]FIG. 3B (extension stroke)  
         [0138]    [0138]FIG. 3B/ 1  Directional control valve  2  is switched to shown position.  
         [0139]    In this position compressed air from line L 1  thru valve  2 , check valve  6  and inlet port  14  is introduced to pressurized chamber B of air cylinder and thru inlet port e thru passage c-b-a to shock absorber/accelerator inner chamber  30 .  
         [0140]    As a result pistons  34  and  12  move simultaneously in arrow direction and the spool valve follows being pushed by spring  37 .  
         [0141]    [0141]FIG. 3B/ 2  After short travel piston  34  sealing structures  36  open aperture  33  and spool valve  37  stops against flange  43 .  
         [0142]    At this point, air supply to inner chamber  30  through spool valve  32  is disconnected and stored compressed air under high pressure rushes through the aperture  33  from the outer chamber  31  to inner chamber  30 , powerfully accelerating piston  34  and through rod  35  air cylinder piston  12  with rod  11  and attached weight.  
         [0143]    After piston  34  stops against block  40 , acceleration process is completed and cylinder piston  12  continues its movement at designed speed under substantially lower pressure in pressurized chamber B.  
         [0144]    Compressed air from chamber A through outlet port  13 , flow control valve  3  and directional control valve  2  is being vented into the atmosphere.  
         [0145]    [0145]FIG. 4 illustrates double wall air cylinder  10  with shock absorber/accelerator  20  mounted to the air cylinder rear end.  
         [0146]    Air cylinder comprises double wall  40  and  41  cylinder body, piston  12  with the rod  11 , front-end head  16  with inlet/outlet  13  and rear end head  17  with inlet/outlet  14 .  
         [0147]    Piston  12  moves with reciprocating motion inside of cylinder body inner tubing  40 .  
         [0148]    Space between walls  40  and  41  is used as outer chamber for shock absorber/accelerator. Sealing structures  18  and  18 A seal piston  12  against tubing  40  and rod  11  against front-end head  16 .  
         [0149]    Shock absorber/accelerator comprises axially movable in body  38  piston  34  with sealing structures  36 , rod  35  attached to the piston, block  39  closing body rear end and spring  51  loaded poppet valve  50  protruding inside inner chamber  30 .  
         [0150]    Shock absorber/accelerator outer chamber is defined by tubes  40  and  41  and communicates with inner chamber through passage  37  and aperture  33 .  
         [0151]    Shock absorber/accelerator piston  35  protrudes into adjacent chamber of the cylinder and sealed by sealing structure  18 B.  
         [0152]    Air cylinder system has two independent air supply lines L 1  and L 2 .  
         [0153]    Air pressure in these lines can be independently adjusted for variety of applications. Line L 1  provides air cylinder reciprocating motion and usually operates under low or moderate air pressure. Line L 1  comprises pressure regulator  7 , two positions directional control valve  2 , flow control valves  3  and  5  and check valves  4  and  6 .  
         [0154]    Line L 2  delivers compressed air to the shock absorber/accelerator chambers and usually operates under high air pressure.  
         [0155]    Line L 2  comprises pressure regulator  8 , two position directional control valve  2 A and check valve  9 .  
         [0156]    [0156]FIG. 4 air cylinder operation described in details in FIG. 5A and FIG. 5B.  
         [0157]    [0157]FIG. 5A (retraction stroke)  
         [0158]    [0158]FIG. 5A/ 1  Compressed air from supply line L 1  thru pressure regulator  7 , directional control valve  2 , check valve  4 , and inlet port  13  is introduced to cylinder pressurized chamber A pushing piston  12  with rod  11  in arrow direction.  
         [0159]    Compressed air from line L 2 , thru pressure regulator  8 , directional control valve  2 A, check valve  9  and aperture  33  enters inner chamber  30  and thru passage  37  outer chamber  31 . At some point of retraction stroke piston  12  meets rod  35  of piston  34  and starts pushing it in arrow direction, compressing air already under pressure thru aperture  33  from inner chamber  30  to the outer chamber  31 .  
         [0160]    Gradually increasing resistance force, created during this process, effectively decelerate moving weight.  
         [0161]    Air from cylinder chamber B thru outlet  14 , flow control valve  5  and directional control valve  2  is vented to the atmosphere.  
         [0162]    Pressure of compressed air stored in outer chamber  31  could be substantially higher than air pressure in supply line L 2 .  
         [0163]    [0163]FIG. 5A/ 2   
         [0164]    Piston  12  moves further until sealing structures  36  seal air coming thru aperture  33  thereby isolating compressed air in outer chamber  31  from the inner chamber  30 .  
         [0165]    At the end of the retraction stroke piston  34  pushes poppet valve  50  to the left thus opening passage which begins at the face of the piston  12  and continues through groove a hole b hole c recess d outlet e for venting of remaining in inner chamber  30  compressed air to the atmosphere. After retraction stroke of the air cylinder piston is fully completed the piston  12  is located in “home position”, compressed air is stored in outer chamber  31  and inner chamber  30  thru poppet valve  50 , outlet e, and directional control valve is connected to the atmosphere.  
         [0166]    Small return force is applied to the piston  34  by compressed spring  51 .  
         [0167]    [0167]FIG. 5B (extension stroke)  
         [0168]    [0168]FIG. 5B/ 1  Directional control valve is switched to the shown position.  
         [0169]    In this position compressed air from line L 1  thru valve  2 , check valve  6  and inlet port  14  is introduced to pressurized chamber B and thru inlet port e and passage to shock absorber/accelerator inner chamber  30 .  
         [0170]    As a result, pistons  34  and  12  begin to move simultaneously in arrow direction.  
         [0171]    Poppet valve follows being pushed by spring  51 .  
         [0172]    Compressed air from chamber A thru outlet port  13 , flow control valve  3  and directional control valve  2  is being exhausted to the atmosphere.  
         [0173]    [0173]FIG. 5B/ 2  After short travel piston  34  seals  36  open aperture  33  and poppet valve  50  stops against block  39 .  
         [0174]    At this point air supply to inner chamber  30  thru poppet valve  50  is disconnected and stored under high pressure compressed air enters thru aperture  33  from outer chamber  31  to inner chamber  30  powerfully accelerating piston  34  and thru rod  35  air cylinder piston  12  with rod  11  and attached weight.  
         [0175]    After piston  34  stops against block  17 , acceleration process is completed and cylinder piston  12  continues to move with uniform velocity under substantially lower air pressure in pressurized chamber B.  
         [0176]    [0176]FIG. 6 Depicts double wall air cylinder with two shock absorbers/accelerators mounted to the both ends of air cylinder.  
         [0177]    This embodiment has the same features as embodiment described in FIG. 4 plus additional shock absorber/accelerator  20 A mounted on cylinder piston front side.  
         [0178]    The outer chamber  31  is defined by tubes  40  and  41  and is connected to both inner chambers  30  thru passages  37  and apertures  33 .  
         [0179]    During extension stroke piston  12  pushes front side piston  34  thru two rods  21  protruding into cylinder chamber A.  
         [0180]    [0180]FIG. 6 retraction stroke is explained in details in FIG. 6A.  
         [0181]    [0181]FIG. 6A.Compressed air from supply line L 1  thru pressure regulator  7  directional control valve  2 , check valve  4  and inlet port  13  is introduced to the cylinder pressurized chamber A and thru inlet port  13 A via recess a- holes b- hole c- annual groove d to shock absorber/accelerator chamber e, thus forcing both pistons to move in arrow direction.  
         [0182]    After short travel aperture  33 A gets open and compressed air under high pressure rushes from outer chamber  31  thru passage  37 A and aperture  33 A into chamber e powerfully accelerating piston  34 A,and thru rod  21  piston  12  with attached weight.  
         [0183]    Pistons  34 A and  12  move together until piston  34 A stops against end block. Since than acceleration phase is almost accomplished and air cylinder piston  12  moves under lower pressure till the end of the cylinder stroke.  
         [0184]    Compressed air from the cylinder discharged chamber B thru outlet port  14 , flow control valve  6  and directional valve  2  is being vented outside.  
         [0185]    [0185]FIG. 7 Illustrates embodiment of air cylinder with rear end mounted shock absorber/accelerator. This embodiment has the same features as FIG. 4 air cylinder but does not have built-in shock absorber/accelerator outer chamber. Air compressed out of inner chamber  30  by piston  34  is stored in self-contained air accumulator  60  located somewhere outside of air cylinder and connected to the inner chamber  30  with air supply line  61 .  
         [0186]    [0186]FIG. 8 Illustrates air cylinder with shock absorber/accelerator mounted to cylinder rear end, having all features described in FIG. 4 embodiment but with outer chamber  70 , defined by mounted to shock absorber/accelerator body  38  tubing  71  and end blocks  72  and  73 . Shock absorber/accelerator inner chamber  30  communicates with outer chamber  70  thru aperture  33 .  
         [0187]    [0187]FIG. 9 Depicts air cylinder  10  with integrated rear end shock absorber/accelerator.  
         [0188]    Air cylinder comprises cylinder body  15 , piston  80  with two sets of sealing structures  36  and  36 A, piston rod  11 , front end head  16  with inlet/outlet  13  and rear end head  82  with inlet/outlet  14 A, inlet e and built-in spring  51  loaded venting poppet valve  50  protruding in air cylinder chamber B  
         [0189]    Cylinder body  15  has two sets of apertures  33  and  33 A.  
         [0190]    Aperture  33  communicates with outer chamber  31  defined by tubing  84 , rear end head  82  and block  81  with inlet/outlet  14 .  
         [0191]    Aperture  33 A communicates with inlet/outlet  14 .  
         [0192]    Linear pitches of aperture  33  and  33 A and piston sealing structures  36  and  36 A are equal and when seals  36  close aperture  33  seals  36 A simultaneously close aperture  33 A.  
         [0193]    The air cylinder air supply system consists of compressed air source  1 , pressure regulator  7 , directional control valve  2 , check valves  4 ,  5 ,  9  and flow controls valves  3  and  6 .  
         [0194]    [0194]FIG. 9A illustrates air cylinder  10  with both ends integrated shock absorber/accelerator. This embodiment has the same features as embodiment described in FIG. 9 plus front end integrated shock absorber/accelerator  20 A.  
         [0195]    [0195]FIG. 9 air cylinder operation is described in details in FIG. 10 and FIG. 11.  
         [0196]    [0196]FIG. 10 (retraction stroke)  
         [0197]    [0197]FIG. 10/ 1 Compressed air from source  1  thru pressure regulator  7 , directional control valve  2  and check valve  4  and inlet port  13  is introduced with pressure P 1  to air cylinder pressurized chamber A and pushes piston  80  with rod  11  in the arrow direction.  
         [0198]    As piston velocity increases the flow control valve  5  resistance and subsequently air pressure P 2  in discharged chamber B also increase until forces applied to the piston  80  from both sides become about equal.  
         [0199]    Compressed air from chamber B thru outlet port  14  flow control valve  5  and directional control valve  2  is being vented to the atmosphere as long as outlet port  14  stays open.  
         [0200]    [0200]FIG. 10/ 2  At certain point of stroke piston first set of structure seals  36  closes aperture outlet port  14  and prevents compressed air remaining in chamber B from exhaust thru this outlet. From this point on cylinder chamber B works as inner chamber of shock absorber/accelerator and compressed air with initial pressure P 2  is pushed by piston  80  thru aperture  33  to the outer chamber  31 .  
         [0201]    Gradually increasing resistance force created during this process effectively decelerates moving weight.  
         [0202]    [0202]FIG. 10/ 3  Piston  80  moves further and first set of sealing structures  36  seals compressed air coming thru aperture  33  thereby isolating compressed air in outer chamber  31  from inner chamber B.  
         [0203]    Air pressure P 2  of compressed air stored in outer chamber  31  could be significantly higher than pressure in supply line L.  
         [0204]    At the end of the stroke piston  80  pushes poppet valve  50  to the left thus opening passage beginning at the face of piston  12  and continuing through groove a - hole b - hole c - recess d - outlet e for venting of remaining in inner chamber B compressed air to the atmosphere.  
         [0205]    After retraction stroke of air cylinder piston is fully completed the piston  80  is located in “home position”, apertures  33  and  33 A are closed by sealing structures  36  and  36 A, compressed air is stored with high pressure in outer chamber  31  and inner chamber thru poppet valve outlet e and directional control valve  2  is connected to the atmosphere. Small return force is applied to the piston  80  by compressed spring  51 .  
         [0206]    [0206]FIG. 11 (extension stroke)  
         [0207]    [0207]FIG. 11/ 1  Directional control valve  2  is switched to the shown position.  
         [0208]    In this position, compressed air thru directional control valve  2 , passage e→d→c→b→a is introduced to the cylinder chamber B.  
         [0209]    At the same time check valves  6  and  9  and flow control valve  5  are also connected to air pressure line.  
         [0210]    As a result piston  80  begins to move in arrow direction and spring loaded poppet valve  50  follows.  
         [0211]    Compressed air from chamber A thru outlet port  13 , flow control valve  3  and directional control valve  2  is being vented to the atmosphere.  
         [0212]    [0212]FIG. 11/ 2  After short travel seals  36  open aperture  33  and poppet valve stops against block  82 . At this time air supply thru poppet valve is disconnected and high-pressure compressed air thru aperture  33  enters cylinder chamber B powerfully accelerating piston  80  in arrow direction.  
         [0213]    [0213]FIG. 11/ 3  The piston  80  moves further and at certain travel point aperture  36 A becomes also open.  
         [0214]    At this point air pressure in outer chamber  31  and cylinder chamber B is decreased and equalized with pressure in air supply line L, acceleration process is completed and piston  80  continues to move being pushed by compressed air with reduced pressure, which is introduced to chamber B from supply line L thru check valve  5 , inlet port  14 , aperture  33 A and thru check valve  9 , inlet port  14 A outer chamber  31  and aperture  33 .  
         [0215]    Extension stroke is completed after piston  80  stops against front-end head  16 .  
         [0216]    [0216]FIG. 12 Illustrates air cylinder  10  with both ends integrated shock absorber/accelerators  20  and  20 A,with external accumulator  70  mounted directly on the cylinder and divided by partition  71  in two chambers  70 A and  70 B.  
         [0217]    Chamber  70 A communicates thru front shock absorber/accelerator aperture  72 A with cylinder chamber A and serves as outer chamber for front shock absorber/accelerator.  
         [0218]    Chamber  70 B communicates thru rear shock absorber/accelerator aperture  70 B with cylinder chamber B and serves as outer chamber for rear end shock absorber/accelerator.  
         [0219]    Otherwise this embodiment has the same features as embodiment described in FIG. 9.  
         [0220]    [0220]FIG. 13 Illustrates air cylinder  10  with both ends integrated shock absorber/accelerators  20  and  20 A and with external accumulator  60  mounted somewhere outside of air cylinder (preferably in cylinder close vicinity).  
         [0221]    Accumulator  60  is divided by partition  61  in two chambers  60 A and  60 B connected thru shock absorbers/accelerator apertures  62 A and  62 B with air cylinder chambers A and B and serving as outer chambers for front and rear shock absorbers/accelerators.  
         [0222]    [0222]FIG. 14 Illustrates air cylinder  10  embodiment with both ends integrated shock absorbers/accelerators  20  and  20 A and with two external accumulators  100 A and  100 B mounted to air cylinders end blocks  101 A and  101 B and serving as outer chambers for shock absorbers/accumulators.