US20120152108A1 - Air pump - Google Patents
Air pump Download PDFInfo
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- US20120152108A1 US20120152108A1 US13/356,544 US201213356544A US2012152108A1 US 20120152108 A1 US20120152108 A1 US 20120152108A1 US 201213356544 A US201213356544 A US 201213356544A US 2012152108 A1 US2012152108 A1 US 2012152108A1
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- cylinder
- piston
- charger
- air pump
- main
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B33/00—Pumps actuated by muscle power, e.g. for inflating
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B35/00—Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for
- F04B35/01—Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for the means being mechanical
Definitions
- the field of the present invention relates to air pumps.
- air pumps are described herein requiring reduced force to achieve a given pressure.
- An air pump comprises a cylinder, a piston, a piston rod, at least three substantially rigid members, and a handle.
- the piston is reciprocably movable within the cylinder and defines a compression volume within the cylinder between the piston and the first end of the cylinder.
- the piston rod is substantially rigidly secured to the piston and extends along the cylinder toward its second end.
- the first member is pivotably connected at its first end to the cylinder.
- the second member is pivotably connected at its first end to the piston rod and is pivotably connected at its second end to the second end of the first member.
- the third member is pivotably connected at its first end to the connected second ends of the first and second members.
- the handle is pivotably connected to the second end of the third member.
- the third member is arranged to transmit between the handle and the connected second ends of the first and second members a force resulting from a force applied to the handle.
- FIGS. 1A-1F illustrate schematically structure and operation of an exemplary embodiment of an air pump.
- FIG. 2 illustrates schematically an exemplary embodiment of an air pump with limiter.
- FIG. 3A illustrates schematically an exemplary embodiment of an air pump with a folding handle.
- FIG. 3B illustrates schematically an exemplary embodiment of an air pump with a base.
- FIG. 4 is an applied force versus pump stroke distance curve for the air pump of FIGS. 1A-1F .
- FIG. 5 is a pressure versus pump stroke distance curve for the air pump of FIGS. 1A-1F .
- FIGS. 6A-6E illustrate schematically structure and operation of another exemplary embodiment of an air pump.
- FIG. 7 is an applied force versus pump stroke angle curve for the air pump of FIGS. 6A-6E .
- FIG. 8 is a pressure versus pump stroke angle curve for the air pump of FIGS. 6A-6E .
- FIG. 9 illustrates schematically a prior-art air pump.
- FIG. 10 illustrates schematically the pump of FIGS. 6A-6E installed on an air gun.
- FIG. 11 is a schematic side view of another exemplary air pump, similar to the air pump of FIGS. 6A-6E but modified for certain uses.
- FIG. 12 is an enlarged view of a portion of FIG. 11 , showing the mechanism at a point of inflection.
- FIG. 13 is a view similar to FIG. 12 , except showing the air pump handle in a closed position.
- FIG. 14 is an enlarged view of a portion of mechanism of FIG. 13 .
- FIG. 15 is an enlarged view of a portion of the handle of FIG. 11 showing the connections between the handle and other elements.
- FIG. 16 is a perspective view of another exemplary embodiment of an air pump.
- FIG. 17 is a enlarged view of a portion of FIG. 16 .
- FIGS. 1A-1F A first exemplary embodiment of an air pump is shown in FIGS. 1A-1F , and comprises: a cylinder 101 ; a piston 102 ; a piston rod 104 ; a first set of three substantially rigid members 106 a, 108 a, and 110 a; a second set of three substantially rigid members 106 b , 108 b, and 110 b; and a handle 112 .
- Piston 102 is reciprocably movable within the cylinder 101 and defines a compression volume 11 within the cylinder 101 between the piston 102 and the first end 116 of the cylinder 101 .
- Piston rod 104 is substantially rigidly secured to the piston 102 and extends along the cylinder 101 toward its second end.
- the first substantially rigid member 106 a is pivotably connected at its first end to the cylinder 101 at pivot 105 a.
- the second substantially rigid member 108 a is pivotably connected at its first end to the piston rod 104 at pivot 107 a and pivotably connected at its second end to the second end of the first member 106 a at pivot 109 a.
- the third substantially rigid member 110 a is pivotably connected at its first end to the connected second ends of the first and second members 106 a and 108 a at pivot 109 a.
- the handle 112 is pivotably connected to the second end of the third member 110 a at pivot 111 a.
- rotation axes of the pivots 105 a, 107 a, 109 a, and 111 a connecting the cylinder 101 , the piston rod 104 , the members 106 a, 108 a, and 110 a, and the handle 112 are substantially parallel to one another and are substantially perpendicular to the axis of the cylinder 101 .
- This arrangement of the pivots 105 a, 107 a, 109 a, and 111 a results in substantially coplanar arrangement and movement of the members 106 a, 108 a, and 110 a as the piston 102 moves along the cylinder 101 .
- Other suitable arrangements shall fall within the scope of the present disclosure or appended claims.
- the third member 110 a is arranged to transmit, between the handle 112 and the connected second ends of the first and second members 106 a and 108 a, a force generally directed toward the first end 116 of the cylinder 101 resulting from a force applied to the handle 112 and generally directed toward the first end 116 of the cylinder.
- the handle 112 is reciprocably movable in a direction substantially parallel to the cylinder 101 and is substantially constrained to linear reciprocating motion by guide rod 114 .
- Guide rod 114 is connected to the handle 112 and reciprocably movable within the piston rod 104 .
- Other suitable structures or arrangements may be employed for guiding substantially linear reciprocating movement of handle 112 in a direction substantially parallel to cylinder 101 .
- FIGS. 1A-1F further comprises a second set of members 106 b, 108 b, and 110 b connected to the cylinder 101 , piston rod 104 , and each other at pivots 105 b, 107 b, 109 b, and 111 b in an arrangement similar to that of the members 106 a, 108 a, and 110 a and the pivots 105 a, 107 a, 109 a, and 111 a.
- the second set of members is arranged on the opposing side of cylinder 101 relative to the first set of members, resulting in substantially coplanar arrangement and movement of all six members as piston 102 moves along cylinder 101 .
- Such a symmetric arrangement applies equivalent forces on pivots 107 a and 107 b and maintains a substantially axisymmetric load on piston rod 104 , reducing the potential for bending the piston rod.
- other positions for the second set of members may be employed, or additional sets of members similarly arranged with pivotable connections among themselves, cylinder 101 , and piston rod 104 may be employed.
- FIGS. 1A-1F The operation of this exemplary pump is illustrated in the sequence of FIGS. 1A-1F .
- the pump is shown at the beginning of a stroke, with the piston 102 at its furthest position from the first end 116 of cylinder 101 and the compression volume 11 at its maximum size.
- Any suitable inlet may be provided for allowing air to enter the compression volume.
- a hole 118 in the side of cylinder 101 may be positioned to allow ambient air to enter the compression volume 11 when piston 102 is at the beginning of a stroke. Once the piston 102 passes the hole 118 during a pump stroke, the air trapped within the compression volume 11 is compressed by further movement of the piston 102 within cylinder 101 .
- Suitable structures or mechanisms may be employed for allowing entry of air into compression volume 101 at the beginning of a pump stroke. Examples may include: a check valve in the side or end of the cylinder; or a sliding o-ring or other suitable seal arranged for forming a seal during the downstroke and for permitting leakage during the upstroke. Air compressed during the pump stroke may exit the compression volume through outlet 120 at the first end 116 of cylinder 101 . Any suitable structure or mechanism may be employed at outlet 120 , including, e.g., a check valve in the cylinder or in the outlet 120 , or a check valve in a fitting connected to the outlet 120 .
- members 106 a, 108 a, and 110 a are described, and are to be understood to apply equivalently to members 106 b, 108 b, and 110 b in this example.
- As force is applied in a downward direction on handle 112 it moves downward, with guide rod 114 sliding into piston rod 104 .
- the force applied to handle 112 is transmitted to the connected ends of the members 106 a and 108 a at pivot 109 a by member 110 a as a force directed generally toward the first end 116 of cylinder 101 .
- the cylinder 101 , the piston 102 , and the piston rod 104 may be arranged so that this minimum compression volume 11 is as small as possible or practicable, so as to maximize the stroke volume of the pump.
- any ending minimum volume for compression volume 11 may be employed as needed or desired, e.g., for achieving a specific desired stroke volume or compression ratio for each pump stroke.
- the minimum compression volume may be chosen so that the maximum pressure achieved in the pump does not exceed maximum pressure safety limits of hoses, fittings, gauges, or other components linked to the pump.
- the air pump may be arranged so that members 106 a and 108 a are substantially parallel to the cylinder (as in FIG. 1F ) when pivot 107 a reaches pivot 105 a. This may be desirable for achieving a desired force versus pressure curve or for storage or portability of the pump (described further hereinbelow).
- the handle 112 and the guide rod 114 can be substantially rigidly connected, or one or both can be arranged so as to enable a substantially rigid connection to be established therebetween when needed or desired.
- the handle 112 can be pivotably connected to the guide rod 114 so as to be movable between a position substantially perpendicular to the cylinder 101 (as in FIGS. 1A-1F ) and a position substantially parallel to the cylinder (as in FIG. 3A ).
- the parallel position may be desirable for storage or portability of the pump, particularly if members 106 a and 108 a are arranged for lying parallel to the cylinder 101 at the end of the downstroke.
- the air pump can further include a base 122 secured to the first end 116 of the cylinder and arranged to enable use of the air pump with the first end of the cylinder resting on the ground (as in FIG. 3B ).
- the base 122 and the cylinder 101 can be substantially rigidly connected, or one or both can be arranged so as to enable a substantially rigid connection to be established therebetween when needed or desired.
- the base 122 can be pivotably connected to the cylinder 101 so as to be movable between a position substantially perpendicular to the cylinder 101 (as in FIGS. 1A-1F ) and a position substantially parallel to the cylinder (not shown).
- the parallel position may be desirable for storage or portability of the pump, particularly if members 106 a and 108 a are arranged for lying parallel to the cylinder 101 at the end of the downstroke.
- FIGS. 1A-1F An air pump configured as shown in FIGS. 1A-1F and constructed with the dimensions given below exhibits applied force versus pump stroke distance curve 402 and pressure versus pump stroke distance curve 502 shown in FIGS. 4 and 5 , respectively.
- the dimensions are:
- member 106a (105a to 109a) 10 inches member 108a (107a to 109a) 10.5 inches member 110a (109a to 111a) 16 inches handle 112 (111a to 114) 8 inches cylinder length (118 to 116) 16.5 inches cylinder diameter 0.75 inches
- pressures of up to 3000 psi can be generated without requiring any applied force greater than about 40 lbs.
- This is in marked contrast to a simple linear pump (corresponding curves 401 and 501 shown in FIGS. 4 and 5 for comparison), wherein up to 200 lbs of force may be required to generate similar reservoir pressure (with a cylinder diameter of about 0.29 inches).
- the air pump of FIGS. 1A-1F delivers over six times the volume per stroke due to the larger piston area. If the stroke volumes are equalized, then the force required using the simple linear pump increases to impractical values (e.g., well over 1000 lbs).
- members 106 a and 106 b can be arranged so as to stop movement of the handle, members, and piston before members 106 a and 106 b become parallel to the cylinder and an infinite mechanical advantage is achieved.
- This infinite mechanical advantage manifests itself as the decrease in force as the distance approaches zero (curve 402 of FIG. 4 ). Since this portion of the pump stroke is somewhat “wasted” (as far as performing work to further compress the air in the cylinder), limiting the motion of members 106 a and 106 b eliminates this “wasted” portion of the pump stroke.
- any suitable mechanical limiter on members 106 a/b , 108 a/b , or 110 a/b , of on the cylinder 101 may be employed for limiting the motion in this way.
- the motion may be limited by arranging piston 102 and cylinder 101 so that piston 102 reaches the end 116 of the cylinder 101 before member 106 a becomes parallel to the cylinder 101 .
- FIGS. 6A-6E A second exemplary embodiment of an air pump is shown in FIGS. 6A-6E , and comprises: a cylinder 201 ; a piston 202 ; a piston rod 204 ; a set of three substantially rigid members 206 , 208 , and 210 ; and a handle 212 .
- Piston 202 is reciprocably movable within the cylinder 201 and defines a compression volume 21 within the cylinder 201 between the piston 202 and the first end 216 of the cylinder 201 .
- Piston rod 204 is substantially rigidly secured to the piston 202 and extends along the cylinder 201 toward its second end.
- the first substantially rigid member 206 is pivotably connected at its first end to the cylinder 201 at pivot 205 .
- the second substantially rigid member 208 is pivotably connected at its first end to the piston rod 204 at pivot 207 and pivotably connected at its second end to the second end of the first member 206 at pivot 209 .
- the third substantially rigid member 210 is pivotably connected at its first end to the connected second ends of the first and second members 206 and 208 at pivot 209 .
- the handle 212 is pivotably connected at its first end to the cylinder 201 at pivot 213 and at an intermediate point to the second end of the third member 210 at pivot 211 . The second end of handle 212 extends beyond pivot 211 .
- rotation axes of the pivots 205 , 207 , 209 , 211 . and 213 connecting the cylinder 201 , the piston rod 204 , the members 206 , 208 , and 210 , and the handle 212 are substantially parallel to one another and are substantially perpendicular to the axis of the cylinder 201 .
- This arrangement of the pivots 205 , 207 , 209 , 211 , and 213 results in substantially coplanar arrangement and movement of the members 206 , 208 , and 210 as the piston 202 moves along the cylinder 201 .
- Other suitable arrangements shall fall within the scope of the present disclosure or appended claims.
- the third member 210 is arranged to transmit, between the handle 212 and the connected second ends of the first and second members 206 and 208 , a force generally directed toward the first end 216 of the cylinder 201 resulting from a force applied to the handle 212 and generally directed toward the first end of cylinder 101 .
- FIGS. 6A-6E The operation of this second exemplary pump is illustrated in the sequence of FIGS. 6A-6E .
- the pump is shown at the beginning of a stroke, with the piston 202 at its furthest position from the first end 216 of cylinder 201 and the compression volume 21 at its maximum size.
- Any suitable inlet may be provided for allowing air to enter the compression volume 21 .
- air trapped within the compression volume 21 is compressed by movement of the piston 202 within cylinder 201 .
- Any suitable structure or mechanism may be employed for allowing entry of air into compression volume 201 at the beginning of a pump stroke, including those recited hereinabove.
- Air compressed during the pump stroke may exit the compression volume through outlet 220 at the first end 216 of cylinder 201 .
- Any suitable structure of mechanism may be employed at outlet 120 , including those recited hereinabove.
- the end of the pump stroke and minimum compression volume occurs when pivot 207 reaches pivot 205 and can go no further, when member 206 or handle 212 encounters cylinder 201 and can be rotated no further (as in FIG. 6E ) or when piston 202 reaches the end 216 of cylinder 201 (whichever comes first).
- the cylinder 201 , the piston 202 , and the piston rod 204 may be arranged so that this minimum compression volume 21 is as small as possible or practicable, so as to maximize the stroke volume or compression ratio of the pump.
- any ending minimum volume for compression volume 21 may be employed as needed or desired (as described hereinabove).
- the minimum compression volume may be chosen so that the maximum pressure achieved in the pump does not exceed maximum pressure safety limits of hosed, fittings, gauges, or other components linked to the pump.
- the air pump may be arranged so that members 206 , 208 , and 210 , and handle 212 are substantially parallel to the cylinder (as in FIG. 6E ) when pivot 207 reaches pivot 205 . This may be desirable for achieving a desired force versus pressure curve or for storage or portability of the pump (described further hereinbelow).
- the pressure within the compression volume 21 reaches the pressure of a target reservoir (plus some additional opening pressure for a suitable valve; reservoir and valve not shown)
- the air in the compression volume 21 flows into the reservoir through outlet 220 .
- the handle 212 may be rotated away from cylinder 201 , reversing the movements of the piston 202 , piston rod 204 , and members 206 , 208 , and 210 in preparation for the next pump stroke.
- the air pump embodiment of FIGS. 6A-6E is well-suited for mounting on an air gun and for charging the air gun 30 for subsequent firing (as shown in FIG. 10 ).
- the air pump outlet can be operatively coupled to a compressed air reservoir in the air gun, which is then used to propel the projectile when the air gun is fired.
- the reservoir may be connected to the barrel of the gun through a firing valve arranged for rapidly releasing the compressed air from the reservoir into the barrel to propel a projectile.
- the three members 206 , 208 , and 210 and the handle 212 are arranged to lie substantially parallel to the cylinder 201 when the piston 202 is positioned to define the minimum operational compression volume 21 (as in FIGS. 6E and 10 ).
- Such an arrangement is particularly appropriate when the air pump is incorporated into an air gun, so that the members 206 , 208 , and 210 and the handle 212 can all lie parallel to and against the body or barrel of the gun without interfering with handling, aiming, or firing the air gun.
- FIGS. 6A-6E An air pump configured as shown in FIGS. 6A-6E and constructed with the dimensions given below exhibits applied force versus piston stroke angle curve 702 and pressure versus piston stroke angle curve 802 shown in FIGS. 7 and 8 , respectively.
- the dimensions are:
- member 206 (205 to 209) 5.35 inches member 208 (207 to 209) 5.90 inches member 210 (209 to 211) 8.40 inches handle 212 (213 to 211) 5.87 inches handle 212 (213 to end) 14 inches cylinder length (202 to 216) 8.90 inches (at 120°) cylinder diameter 0.75 inches
- pressures of greater than 2000 psi can be generated with eight strokes without requiring any applied force greater than about 10 lbs. This is in contrast to prior air gun pump mechanisms (such as pump 90 shown in FIG. 9 ; corresponding curves 701 and 801 shown in FIGS. 7 and 8 for comparison), wherein over 30 lbs of force may be required to generate similar compressed air pressure.
- prior air gun pump mechanisms such as pump 90 shown in FIG. 9 ; corresponding curves 701 and 801 shown in FIGS. 7 and 8 for comparison
- These dimensions are exemplary only; a wide variety of combinations of dimensions may be employed for achieving a needed or desired force or pressure versus distance curves depending on the operational requirements of the air pump.
- One example of a desirable force profile would be a relatively flat profile, wherein the force is relatively constant (within operationally acceptable limits) over the duration of the pump stroke.
- the curves may be readily calculated using standard mechanical engineering techniques described in a variety of basic text books (e.g., Erdman and Sandor cited hereinabove).
- the reduction in force required to adequately pump the air gun for firing results in a lesser degree of fatigue for the user, in turn enabling improved shooting accuracy.
- FIGS. 6A-6E reduces the maximum force required to pump air guns relative to the prior art mechanism of FIG. 9 , yet substantially conforms to the standard shape and motion of standard air gun pump mechanisms.
- the members are all located on one side of the gun under the barrel and the cocking handle is normally part of the stock.
- the length of each element described in the previous table interacts to determine the shape of the handle force curve depicted in FIG. 7 .
- the lengths of the members can be selected so as to yield a relatively flat force profile (within operationally acceptable limits).
- the members can be arranged so as to collapse into the cylinder to create a smooth gun profile after cocking.
- the handle and members can be arranged so that an inversion of members 212 , 210 , and 206 hold handle 212 in position against cylinder 21 under the force from pressure on piston 202 .
- the handle 212 has been rotated beyond the inversion point of the linkage members, and the piston 202 /piston rod 204 are exerting a force on the linkage tending to keep the handle in the closed position as shown.
- FIGS. 11-13 show a modified air pump, and also show how the handle 212 is retained against the cylinder in a closed position, e.g., after cocking, with the other linkage members nested together.
- FIG. 11 is a side view of the modified air pump, which is similar to FIG. 6A , except FIG. 11 shows the modified air pump from the opposite side. As in FIG. 6A , the air pump of FIG.
- FIG. 12 is an enlarged view showing a portion of the air pump of FIG. 11 after the handle 212 has been rotated through most of its stroke, such that the linkage is at an inversion point. Specifically, the handle 212 has been rotated counterclockwise in the direction of arrow R, and through the handle's interaction with the member 210 connected to the handle, the member 208 connected to the member 210 and the piston rod 204 connected to the member 208 , the piston 202 has been urged leftward from its position in FIG. 11 , thereby compressing the fluid within the compression volume 21 .
- the linkage is at an inversion point as shown by the aligned positions of the pivot 209 , the pivot 205 and the pivot 207 along the line I.
- Further rotation of the handle 212 in the direction of arrow R beyond the position shown in FIG. 12 will not produce additional force tending to urge the piston 202 leftward, but instead will decrease the force urging the piston 202 leftward.
- any accumulated pressure in the compression volume 21 will exert a force on the piston 202 tending to urge it rightward, and if this force exceeds the leftward force, the piston will be urged rightward.
- FIG. 13 is similar to FIG. 12 , but in FIG. 13 , the handle 212 is shown in the closed position, with the members 206 , 208 and 210 nested together and the member 206 in contact with the cylinder 201 . Any accumulated pressure in compression volume 21 will tend to keep the handle 212 and the members 206 , 208 and 210 in the closed position as shown.
- one or more of the pivot connections can be configured to allow translation.
- the member 210 can be provided with a slotted opening 214 through which the pivot 211 extends, instead of a circular opening, to allow some freedom for relative translation between the connected members, particularly as the handle is moved from the inversion point ( FIG. 12 ) to the closed position ( FIG. 13 ).
- the handle 212 as illustrated in FIGS. 11-15 can be configured with an arcuate shaped slot (or groove) 216 having an elongated portion 220 at one end and a pin (or roller) 218 extending from the member 210 and dimensioned to travel within the slot 216 .
- the pin 218 travels within and is constrained by a side of the slot 216 over most of the rotation of the handle 212 from the open position ( FIG. 15 ) to the inversion point, and thus the pin 218 exerts force through the member 210 on the rest of the linkage over this range.
- the elongated portion 220 of the slot 216 and the slotted opening 214 are aligned as shown, each providing for relative translation of the handle 212 and the member 210 . This allows for more positive movement of the handle from the inflection point position to the closed position and from the closed position to an open position.
- the handle 212 can be fitted with a magnet, shown schematically at 222 in FIG. 12 , to help retain the handle against the cylinder 201 .
- a torsion spring can be fitted between pivots 211 and roller 218 such that the roller 218 is forced into elongated groove 220 , thereby holding member 210 and handle 212 in parallel alignment and retaining handle 212 against the cylinder 210 .
- an air pump 300 also has a system of linkages that allows for a nearly consistent force to be applied to the handle over nearly the entire length of the stroke, thus avoiding the “pressure to inverse volume reduction” relationship characteristic of linear cylinder pumps.
- the air pump 300 which as illustrated is implemented as a floor pump, is fitted with a pre-charger 310 .
- the pre-charger 310 comprises a second cylinder 312 and second piston 314 combination that amplifies atmospheric pressure in the primary cylinder during the upward stroke (or non-power stroke) and prior to the compression stroke. Without the pre-charger, the floor pump 300 would need to be configured to have double the stroke height and thereby would become impractical for a person of normal stature to operate in a reasonable manner.
- the piston 314 is pulled upward by rod 316 as the handle 205 is raised.
- a o-ring 320 slidable within a groove 321 on piston 314 allows the o-ring to seal the cylinder 312 on the upward stroke (compression stroke).
- the compressed air from the compression stroke travels through port 322 and tube 324 and through port 326 and check valve 328 on ( FIG. 3 ) into main compression chamber 209 .
- the o-ring groove 321 is dimensioned wider than the o-ring 320 .
- the o-ring 320 slides within the o-ring groove 321 such that a by-pass channel 323 through the piston 314 is open and atmospheric air can flow to the upper portion of the cylinder (above the piston) from the lower portion (below the piston).
- the atmospheric air is replenished through a port 313 located in the wall of the cylinder 312 near its lower end.
- the o-ring 320 slides downward within the o-ring groove 321 and seals the by-pass channel 323 , sealing the air in the upper cylinder.
- the slidable o-ring and by-pass channel serve as a check valve to transfer atmospheric pressure into the upper portion of the cylinder 312 . Accordingly, a check valve or any other structure suitable for transferring atmospheric pressure across the piston 314 can be used.
- a relief valve 330 is added to the top 331 of the pre-charge cylinder 312 as shown in FIG. 17 .
- the relief valve 330 has a spring loaded ball seal that vents to atmosphere through a port 332 when the internal pre-charge pressure exceeds a predefined limit (approximately two times atmospheric pressure or about 30 PSI absolute pressure).
- This relief valve 330 maintains a constant pre-charge pressure in the main cylinder prior to the power stroke and it also reduces the force required during the up-stroke (pre-charge stroke) by relieving any excess pre-charge pressure above that required to pre-charge the main cylinder.
- connection . . . to shall denote a connection between two objects either directly or through some intermediate object or member.
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Abstract
An air pump comprises a main cylinder, a main piston, a piston rod, a linkage, and a pre-charger. The main piston is reciprocably movable within the main cylinder and defines a compression volume between the main piston and a first end of the main cylinder. The piston rod is connected to the main piston and extends along the main cylinder towards a second end. The linkage is configured to move the main piston and to generate pressure in the compression volume during a compression stroke, the linkage having ends pivotably connected to the main cylinder and to the piston rod. The pre-charger has a pre-charger piston movable within a pre-charger cylinder and is connected to the linkage to move within the pre-charger cylinder when the main piston moves within the main cylinder, the pre-charger generating pressure to augment operation of the main piston and main cylinder.
Description
- This application is a continuation-in-part of U.S. patent application Ser. No. 12/648,157, filed Dec. 28, 2009, which is a continuation-in-part of U.S. patent application Ser. No. 11/464,192, filed Aug. 12, 2006, now U.S. Pat. No. 7,637,203. These prior applications are incorporated herein by reference.
- The field of the present invention relates to air pumps. In particular, air pumps are described herein requiring reduced force to achieve a given pressure.
- Many previous air pumps exhibit applied force versus pump stroke distance profiles that increase steeply toward the end of the pump stroke, or are sharply peaked near the end of the pump stroke. The large forces required are often difficult, if not impossible, for a user to achieve. Stroke volumes of many prior pumps are small, so that dozens or even hundreds of strokes are required to pressurize an adequate volume of air (to fill a tire or pressurize a reservoir, for example. It may be desirable to provide a pump wherein the applied force versus pump stroke distance is less steep, less highly peaked, or somewhat flattened; or it may be desirable to provide a pump having an increased stroke volume without a concomitant increase in pump force required.
- An air pump comprises a cylinder, a piston, a piston rod, at least three substantially rigid members, and a handle. The piston is reciprocably movable within the cylinder and defines a compression volume within the cylinder between the piston and the first end of the cylinder. The piston rod is substantially rigidly secured to the piston and extends along the cylinder toward its second end. The first member is pivotably connected at its first end to the cylinder. The second member is pivotably connected at its first end to the piston rod and is pivotably connected at its second end to the second end of the first member. The third member is pivotably connected at its first end to the connected second ends of the first and second members. The handle is pivotably connected to the second end of the third member. The third member is arranged to transmit between the handle and the connected second ends of the first and second members a force resulting from a force applied to the handle.
- Objects and advantages pertaining to air pumps may become apparent upon referring to the exemplary embodiments illustrated in the drawings and disclosed in the following written description or claims.
-
FIGS. 1A-1F illustrate schematically structure and operation of an exemplary embodiment of an air pump. -
FIG. 2 illustrates schematically an exemplary embodiment of an air pump with limiter. -
FIG. 3A illustrates schematically an exemplary embodiment of an air pump with a folding handle.FIG. 3B illustrates schematically an exemplary embodiment of an air pump with a base. -
FIG. 4 is an applied force versus pump stroke distance curve for the air pump ofFIGS. 1A-1F . -
FIG. 5 is a pressure versus pump stroke distance curve for the air pump ofFIGS. 1A-1F . -
FIGS. 6A-6E illustrate schematically structure and operation of another exemplary embodiment of an air pump. -
FIG. 7 is an applied force versus pump stroke angle curve for the air pump ofFIGS. 6A-6E . -
FIG. 8 is a pressure versus pump stroke angle curve for the air pump ofFIGS. 6A-6E . -
FIG. 9 illustrates schematically a prior-art air pump. -
FIG. 10 illustrates schematically the pump ofFIGS. 6A-6E installed on an air gun. -
FIG. 11 is a schematic side view of another exemplary air pump, similar to the air pump ofFIGS. 6A-6E but modified for certain uses. -
FIG. 12 is an enlarged view of a portion ofFIG. 11 , showing the mechanism at a point of inflection. -
FIG. 13 is a view similar toFIG. 12 , except showing the air pump handle in a closed position. -
FIG. 14 is an enlarged view of a portion of mechanism ofFIG. 13 . -
FIG. 15 is an enlarged view of a portion of the handle ofFIG. 11 showing the connections between the handle and other elements. -
FIG. 16 is a perspective view of another exemplary embodiment of an air pump. -
FIG. 17 is a enlarged view of a portion ofFIG. 16 . - The embodiments shown in the Figures are exemplary, and should not be construed as limiting the scope of the present disclosure or appended claims.
- A first exemplary embodiment of an air pump is shown in
FIGS. 1A-1F , and comprises: acylinder 101; apiston 102; apiston rod 104; a first set of three substantiallyrigid members rigid members handle 112. Piston 102 is reciprocably movable within thecylinder 101 and defines acompression volume 11 within thecylinder 101 between thepiston 102 and thefirst end 116 of thecylinder 101. Pistonrod 104 is substantially rigidly secured to thepiston 102 and extends along thecylinder 101 toward its second end. The first substantiallyrigid member 106 a is pivotably connected at its first end to thecylinder 101 atpivot 105 a. The second substantiallyrigid member 108 a is pivotably connected at its first end to thepiston rod 104 atpivot 107 a and pivotably connected at its second end to the second end of thefirst member 106 a atpivot 109 a. The third substantiallyrigid member 110 a is pivotably connected at its first end to the connected second ends of the first andsecond members pivot 109 a. Thehandle 112 is pivotably connected to the second end of thethird member 110 a atpivot 111 a. - In the exemplary embodiment, rotation axes of the
pivots cylinder 101, thepiston rod 104, themembers handle 112 are substantially parallel to one another and are substantially perpendicular to the axis of thecylinder 101. This arrangement of thepivots members piston 102 moves along thecylinder 101. Other suitable arrangements shall fall within the scope of the present disclosure or appended claims. Thethird member 110 a is arranged to transmit, between thehandle 112 and the connected second ends of the first andsecond members first end 116 of thecylinder 101 resulting from a force applied to thehandle 112 and generally directed toward thefirst end 116 of the cylinder. - In the exemplary embodiment of
FIGS. 1A-1F , thehandle 112 is reciprocably movable in a direction substantially parallel to thecylinder 101 and is substantially constrained to linear reciprocating motion byguide rod 114.Guide rod 114 is connected to thehandle 112 and reciprocably movable within thepiston rod 104. Other suitable structures or arrangements may be employed for guiding substantially linear reciprocating movement ofhandle 112 in a direction substantially parallel tocylinder 101. - The exemplary embodiment of
FIGS. 1A-1F further comprises a second set ofmembers cylinder 101,piston rod 104, and each other atpivots members pivots cylinder 101 relative to the first set of members, resulting in substantially coplanar arrangement and movement of all six members aspiston 102 moves alongcylinder 101. Such a symmetric arrangement applies equivalent forces onpivots piston rod 104, reducing the potential for bending the piston rod. In alternative embodiments, other positions for the second set of members may be employed, or additional sets of members similarly arranged with pivotable connections among themselves,cylinder 101, andpiston rod 104 may be employed. - The operation of this exemplary pump is illustrated in the sequence of
FIGS. 1A-1F . InFIG. 1A , the pump is shown at the beginning of a stroke, with thepiston 102 at its furthest position from thefirst end 116 ofcylinder 101 and thecompression volume 11 at its maximum size. Any suitable inlet may be provided for allowing air to enter the compression volume. For example, ahole 118 in the side ofcylinder 101 may be positioned to allow ambient air to enter thecompression volume 11 whenpiston 102 is at the beginning of a stroke. Once thepiston 102 passes thehole 118 during a pump stroke, the air trapped within thecompression volume 11 is compressed by further movement of thepiston 102 withincylinder 101. Other suitable structures or mechanisms may be employed for allowing entry of air intocompression volume 101 at the beginning of a pump stroke. Examples may include: a check valve in the side or end of the cylinder; or a sliding o-ring or other suitable seal arranged for forming a seal during the downstroke and for permitting leakage during the upstroke. Air compressed during the pump stroke may exit the compression volume throughoutlet 120 at thefirst end 116 ofcylinder 101. Any suitable structure or mechanism may be employed atoutlet 120, including, e.g., a check valve in the cylinder or in theoutlet 120, or a check valve in a fitting connected to theoutlet 120. - In the following, the arrangements and movements of
members members handle 112, it moves downward, withguide rod 114 sliding intopiston rod 104. The force applied to handle 112 is transmitted to the connected ends of themembers pivot 109 a bymember 110 a as a force directed generally toward thefirst end 116 ofcylinder 101. This results in downward rotation ofmember 106 a aboutpivot 105 a, and tension being applied tomember 108 a, which in turn urgespiston rod 104 andpiston 102 downward withincylinder 101 and reduces thecompression volume 11. The sequence of movements is illustrated inFIGS. 1A-1F . Oncepiston 102 passes hole 118 (as inFIG. 3B ), the air trapped within thecompression volume 11 is compressed by further movement ofpiston 102 downward withincylinder 101. The end of the pump stroke (i.e., downstroke) and minimum compression volume occurs whenpivot 107 a reaches pivot 105 a and can go no further (as inFIG. 1F ), or whenmember 106 aencounters cylinder 101 and can be rotated no further, or whenpiston 102 reaches theend 116 of the cylinder 101 (whichever comes first). Thecylinder 101, thepiston 102, and thepiston rod 104 may be arranged so that thisminimum compression volume 11 is as small as possible or practicable, so as to maximize the stroke volume of the pump. However, any ending minimum volume forcompression volume 11 may be employed as needed or desired, e.g., for achieving a specific desired stroke volume or compression ratio for each pump stroke. For example, the minimum compression volume may be chosen so that the maximum pressure achieved in the pump does not exceed maximum pressure safety limits of hoses, fittings, gauges, or other components linked to the pump. - The air pump may be arranged so that
members FIG. 1F ) whenpivot 107 a reaches pivot 105 a. This may be desirable for achieving a desired force versus pressure curve or for storage or portability of the pump (described further hereinbelow). Once the pressure within thecompression volume 11 reaches the pressure of a target reservoir (plus some additional opening pressure for a suitable valve; reservoir and valve not shown), the air in thecompression volume 11 flows into the reservoir throughoutlet 120. Once the downstroke is completed, thehandle 112 is pulled upward, reversing the movements of thepiston 102,piston rod 104, andmembers piston 102 passes hole 118 on its way upward through the cylinder 101 (i.e., on the upstroke, or recovery stroke), more air enters thecylinder 101 through thehole 118 for compression during the next downstroke. - The
handle 112 and theguide rod 114 can be substantially rigidly connected, or one or both can be arranged so as to enable a substantially rigid connection to be established therebetween when needed or desired. In an example of this second case, thehandle 112 can be pivotably connected to theguide rod 114 so as to be movable between a position substantially perpendicular to the cylinder 101 (as inFIGS. 1A-1F ) and a position substantially parallel to the cylinder (as inFIG. 3A ). The parallel position may be desirable for storage or portability of the pump, particularly ifmembers cylinder 101 at the end of the downstroke. The air pump can further include a base 122 secured to thefirst end 116 of the cylinder and arranged to enable use of the air pump with the first end of the cylinder resting on the ground (as inFIG. 3B ). Thebase 122 and thecylinder 101 can be substantially rigidly connected, or one or both can be arranged so as to enable a substantially rigid connection to be established therebetween when needed or desired. In an example of this second case, the base 122 can be pivotably connected to thecylinder 101 so as to be movable between a position substantially perpendicular to the cylinder 101 (as inFIGS. 1A-1F ) and a position substantially parallel to the cylinder (not shown). The parallel position may be desirable for storage or portability of the pump, particularly ifmembers cylinder 101 at the end of the downstroke. - An air pump configured as shown in
FIGS. 1A-1F and constructed with the dimensions given below exhibits applied force versus pumpstroke distance curve 402 and pressure versus pumpstroke distance curve 502 shown inFIGS. 4 and 5 , respectively. The dimensions are: -
member 106a (105a to 109a)10 inches member 108a (107a to 109a) 10.5 inches member 110a (109a to 111a) 16 inches handle 112 (111a to 114) 8 inches cylinder length (118 to 116) 16.5 inches cylinder diameter 0.75 inches - When constructed with these dimensions, pressures of up to 3000 psi can be generated without requiring any applied force greater than about 40 lbs. This is in marked contrast to a simple linear pump (corresponding
curves FIGS. 4 and 5 for comparison), wherein up to 200 lbs of force may be required to generate similar reservoir pressure (with a cylinder diameter of about 0.29 inches). In addition to the reduced force requirement, the air pump ofFIGS. 1A-1F delivers over six times the volume per stroke due to the larger piston area. If the stroke volumes are equalized, then the force required using the simple linear pump increases to impractical values (e.g., well over 1000 lbs). These dimensions are exemplary only; a wide variety of combinations of dimensions may be employed for achieving a needed or desired force/pressure versus distance curves depending on the operational requirements of the air pump. One example of a desirable force profile would be a relatively flat profile, wherein the force is relatively constant (within operationally acceptable limits) over the duration of the pump stroke. Force-distance and pressure-distance curves may be readily calculated using standard mechanical engineering techniques described in a variety of basic text books (e.g., Arthur G. Erdman and George N. Sandor, Mechanism Design: Analysis and Synthesis, 2ed Prentice Hall (1984), hereby incorporated by reference as if fully set forth herein). - As shown in
FIG. 2 ,members members curve 402 ofFIG. 4 ). Since this portion of the pump stroke is somewhat “wasted” (as far as performing work to further compress the air in the cylinder), limiting the motion ofmembers members 106 a/b, 108 a/b, or 110 a/b, of on thecylinder 101 may be employed for limiting the motion in this way. Alternatively, the motion may be limited by arrangingpiston 102 andcylinder 101 so thatpiston 102 reaches theend 116 of thecylinder 101 beforemember 106 a becomes parallel to thecylinder 101. - A second exemplary embodiment of an air pump is shown in
FIGS. 6A-6E , and comprises: acylinder 201; apiston 202; apiston rod 204; a set of three substantiallyrigid members handle 212.Piston 202 is reciprocably movable within thecylinder 201 and defines acompression volume 21 within thecylinder 201 between thepiston 202 and thefirst end 216 of thecylinder 201.Piston rod 204 is substantially rigidly secured to thepiston 202 and extends along thecylinder 201 toward its second end. The first substantiallyrigid member 206 is pivotably connected at its first end to thecylinder 201 atpivot 205. The second substantiallyrigid member 208 is pivotably connected at its first end to thepiston rod 204 atpivot 207 and pivotably connected at its second end to the second end of thefirst member 206 atpivot 209. The third substantiallyrigid member 210 is pivotably connected at its first end to the connected second ends of the first andsecond members pivot 209. Thehandle 212 is pivotably connected at its first end to thecylinder 201 atpivot 213 and at an intermediate point to the second end of thethird member 210 atpivot 211. The second end ofhandle 212 extends beyondpivot 211. - In this exemplary embodiment, rotation axes of the
pivots cylinder 201, thepiston rod 204, themembers handle 212 are substantially parallel to one another and are substantially perpendicular to the axis of thecylinder 201. This arrangement of thepivots members piston 202 moves along thecylinder 201. Other suitable arrangements shall fall within the scope of the present disclosure or appended claims. Thethird member 210 is arranged to transmit, between thehandle 212 and the connected second ends of the first andsecond members first end 216 of thecylinder 201 resulting from a force applied to thehandle 212 and generally directed toward the first end ofcylinder 101. - The operation of this second exemplary pump is illustrated in the sequence of
FIGS. 6A-6E . InFIG. 6A , the pump is shown at the beginning of a stroke, with thepiston 202 at its furthest position from thefirst end 216 ofcylinder 201 and thecompression volume 21 at its maximum size. Any suitable inlet may be provided for allowing air to enter thecompression volume 21. During a pump stroke, air trapped within thecompression volume 21 is compressed by movement of thepiston 202 withincylinder 201. Any suitable structure or mechanism may be employed for allowing entry of air intocompression volume 201 at the beginning of a pump stroke, including those recited hereinabove. Air compressed during the pump stroke may exit the compression volume throughoutlet 220 at thefirst end 216 ofcylinder 201. Any suitable structure of mechanism may be employed atoutlet 120, including those recited hereinabove. - As force is applied on the end of
handle 212, it rotates toward thecylinder 201 aboutpivot 213. The force applied to handle 212 is transmitted to the connected ends of themembers pivot 209 bymember 210 as a force directed generally toward thefirst end 216 ofcylinder 201. This results in rotation ofmember 206 aboutpivot 205, and tension being applied tomember 208, which in turn urgespiston rod 204 andpiston 202 towardend 116 withincylinder 101 and reduces thecompression volume 21. The sequence of movements in illustrated inFIGS. 6A-6E . Air trapped within thecompression volume 21 is compressed by movement ofpiston 202 withincylinder 201. The end of the pump stroke and minimum compression volume occurs whenpivot 207 reachespivot 205 and can go no further, whenmember 206 or handle 212encounters cylinder 201 and can be rotated no further (as inFIG. 6E ) or whenpiston 202 reaches theend 216 of cylinder 201 (whichever comes first). Thecylinder 201, thepiston 202, and thepiston rod 204 may be arranged so that thisminimum compression volume 21 is as small as possible or practicable, so as to maximize the stroke volume or compression ratio of the pump. However, any ending minimum volume forcompression volume 21 may be employed as needed or desired (as described hereinabove). For example, the minimum compression volume may be chosen so that the maximum pressure achieved in the pump does not exceed maximum pressure safety limits of hosed, fittings, gauges, or other components linked to the pump. - The air pump may be arranged so that
members FIG. 6E ) whenpivot 207 reachespivot 205. This may be desirable for achieving a desired force versus pressure curve or for storage or portability of the pump (described further hereinbelow). Once the pressure within thecompression volume 21 reaches the pressure of a target reservoir (plus some additional opening pressure for a suitable valve; reservoir and valve not shown), the air in thecompression volume 21 flows into the reservoir throughoutlet 220. Once the pump stroke is completed, thehandle 212 may be rotated away fromcylinder 201, reversing the movements of thepiston 202,piston rod 204, andmembers - The air pump embodiment of
FIGS. 6A-6E is well-suited for mounting on an air gun and for charging theair gun 30 for subsequent firing (as shown inFIG. 10 ). The air pump outlet can be operatively coupled to a compressed air reservoir in the air gun, which is then used to propel the projectile when the air gun is fired. The reservoir may be connected to the barrel of the gun through a firing valve arranged for rapidly releasing the compressed air from the reservoir into the barrel to propel a projectile. The threemembers handle 212 are arranged to lie substantially parallel to thecylinder 201 when thepiston 202 is positioned to define the minimum operational compression volume 21 (as inFIGS. 6E and 10 ). Such an arrangement is particularly appropriate when the air pump is incorporated into an air gun, so that themembers handle 212 can all lie parallel to and against the body or barrel of the gun without interfering with handling, aiming, or firing the air gun. - An air pump configured as shown in
FIGS. 6A-6E and constructed with the dimensions given below exhibits applied force versus pistonstroke angle curve 702 and pressure versus pistonstroke angle curve 802 shown inFIGS. 7 and 8 , respectively. The dimensions are: -
member 206 (205 to 209) 5.35 inches member 208 (207 to 209) 5.90 inches member 210 (209 to 211) 8.40 inches handle 212 (213 to 211) 5.87 inches handle 212 (213 to end) 14 inches cylinder length (202 to 216) 8.90 inches (at 120°) cylinder diameter 0.75 inches - When constructed with these dimensions, pressures of greater than 2000 psi can be generated with eight strokes without requiring any applied force greater than about 10 lbs. This is in contrast to prior air gun pump mechanisms (such as
pump 90 shown inFIG. 9 ; correspondingcurves FIGS. 7 and 8 for comparison), wherein over 30 lbs of force may be required to generate similar compressed air pressure. These dimensions are exemplary only; a wide variety of combinations of dimensions may be employed for achieving a needed or desired force or pressure versus distance curves depending on the operational requirements of the air pump. One example of a desirable force profile would be a relatively flat profile, wherein the force is relatively constant (within operationally acceptable limits) over the duration of the pump stroke. The curves may be readily calculated using standard mechanical engineering techniques described in a variety of basic text books (e.g., Erdman and Sandor cited hereinabove). The reduction in force required to adequately pump the air gun for firing results in a lesser degree of fatigue for the user, in turn enabling improved shooting accuracy. - This embodiment of
FIGS. 6A-6E reduces the maximum force required to pump air guns relative to the prior art mechanism ofFIG. 9 , yet substantially conforms to the standard shape and motion of standard air gun pump mechanisms. The members are all located on one side of the gun under the barrel and the cocking handle is normally part of the stock. The length of each element described in the previous table interacts to determine the shape of the handle force curve depicted inFIG. 7 . The lengths of the members can be selected so as to yield a relatively flat force profile (within operationally acceptable limits). - The members can be arranged so as to collapse into the cylinder to create a smooth gun profile after cocking. The handle and members can be arranged so that an inversion of
members hold handle 212 in position againstcylinder 21 under the force from pressure onpiston 202. As shown inFIG. 6E , thehandle 212 has been rotated beyond the inversion point of the linkage members, and thepiston 202/piston rod 204 are exerting a force on the linkage tending to keep the handle in the closed position as shown. - As another example,
FIGS. 11-13 show a modified air pump, and also show how thehandle 212 is retained against the cylinder in a closed position, e.g., after cocking, with the other linkage members nested together.FIG. 11 is a side view of the modified air pump, which is similar toFIG. 6A , exceptFIG. 11 shows the modified air pump from the opposite side. As inFIG. 6A , the air pump ofFIG. 11 is shown at the beginning of its stroke, with itshandle 212 in an open position, with thepiston 202 retracted (i.e., at its furthest position from thefirst end 216 of the cylinder 201) and poised to translate via the action of thehandle 212 in conjunction with the piston rod, theother linkage members pivot connections -
FIG. 12 is an enlarged view showing a portion of the air pump ofFIG. 11 after thehandle 212 has been rotated through most of its stroke, such that the linkage is at an inversion point. Specifically, thehandle 212 has been rotated counterclockwise in the direction of arrow R, and through the handle's interaction with themember 210 connected to the handle, themember 208 connected to themember 210 and thepiston rod 204 connected to themember 208, thepiston 202 has been urged leftward from its position inFIG. 11 , thereby compressing the fluid within thecompression volume 21. - At the approximate position of the stroke shown in
FIG. 12 , the linkage is at an inversion point as shown by the aligned positions of thepivot 209, thepivot 205 and thepivot 207 along the line I. Further rotation of thehandle 212 in the direction of arrow R beyond the position shown inFIG. 12 will not produce additional force tending to urge thepiston 202 leftward, but instead will decrease the force urging thepiston 202 leftward. At the same time, any accumulated pressure in thecompression volume 21 will exert a force on thepiston 202 tending to urge it rightward, and if this force exceeds the leftward force, the piston will be urged rightward. -
FIG. 13 is similar toFIG. 12 , but inFIG. 13 , thehandle 212 is shown in the closed position, with themembers member 206 in contact with thecylinder 201. Any accumulated pressure incompression volume 21 will tend to keep thehandle 212 and themembers - To further assist in maintaining the
handle 212 in the closed position, one or more of the pivot connections can be configured to allow translation. For example, with reference toFIGS. 12 , 13 and 14, themember 210 can be provided with a slottedopening 214 through which thepivot 211 extends, instead of a circular opening, to allow some freedom for relative translation between the connected members, particularly as the handle is moved from the inversion point (FIG. 12 ) to the closed position (FIG. 13 ). - In addition, the
handle 212 as illustrated inFIGS. 11-15 can be configured with an arcuate shaped slot (or groove) 216 having anelongated portion 220 at one end and a pin (or roller) 218 extending from themember 210 and dimensioned to travel within theslot 216. The arrangement of theslot 216 and thepin 218 acting as a cam and follower and collectively referred to as a clutch. Thepin 218 travels within and is constrained by a side of theslot 216 over most of the rotation of thehandle 212 from the open position (FIG. 15 ) to the inversion point, and thus thepin 218 exerts force through themember 210 on the rest of the linkage over this range. At the inversion point inFIG. 12 , relative movement of thehandle 212 and themember 210 causes thepin 218 to be guided into theelongated portion 220 of theslot 216, in which position thepin 218 is free to translate and does not transfer force from thehandle 212. Rather, thehandle 212 is disengaged from transferring force at this point. Themember 210 is unloaded, so it no longer carries a force, and it is free to float between thepivots - If the arrangement of the
slot 216 and thepin 218 is provided together with the slottedopening 214, theelongated portion 220 of theslot 216 and the slottedopening 214 are aligned as shown, each providing for relative translation of thehandle 212 and themember 210. This allows for more positive movement of the handle from the inflection point position to the closed position and from the closed position to an open position. - If desired, the
handle 212 can be fitted with a magnet, shown schematically at 222 inFIG. 12 , to help retain the handle against thecylinder 201. Alternatively, a torsion spring can be fitted betweenpivots 211 androller 218 such that theroller 218 is forced into elongatedgroove 220, thereby holdingmember 210 and handle 212 in parallel alignment and retaininghandle 212 against thecylinder 210. - According to another exemplary embodiment as shown in
FIGS. 16 and 17 , anair pump 300 also has a system of linkages that allows for a nearly consistent force to be applied to the handle over nearly the entire length of the stroke, thus avoiding the “pressure to inverse volume reduction” relationship characteristic of linear cylinder pumps. Theair pump 300, which as illustrated is implemented as a floor pump, is fitted with a pre-charger 310. The pre-charger 310 comprises asecond cylinder 312 andsecond piston 314 combination that amplifies atmospheric pressure in the primary cylinder during the upward stroke (or non-power stroke) and prior to the compression stroke. Without the pre-charger, thefloor pump 300 would need to be configured to have double the stroke height and thereby would become impractical for a person of normal stature to operate in a reasonable manner. - The
piston 314 is pulled upward byrod 316 as thehandle 205 is raised. As best shown inFIG. 17 , a o-ring 320 slidable within agroove 321 onpiston 314 allows the o-ring to seal thecylinder 312 on the upward stroke (compression stroke). The compressed air from the compression stroke travels throughport 322 andtube 324 and throughport 326 andcheck valve 328 on (FIG. 3 ) intomain compression chamber 209. As best seen inFIG. 17 , the o-ring groove 321 is dimensioned wider than the o-ring 320. On the downward stroke (recharge stroke), the o-ring 320 slides within the o-ring groove 321 such that a by-pass channel 323 through thepiston 314 is open and atmospheric air can flow to the upper portion of the cylinder (above the piston) from the lower portion (below the piston). The atmospheric air is replenished through aport 313 located in the wall of thecylinder 312 near its lower end. On the upward stroke, the o-ring 320 slides downward within the o-ring groove 321 and seals the by-pass channel 323, sealing the air in the upper cylinder. Thus, the slidable o-ring and by-pass channel serve as a check valve to transfer atmospheric pressure into the upper portion of thecylinder 312. Accordingly, a check valve or any other structure suitable for transferring atmospheric pressure across thepiston 314 can be used. - To maintain a relatively constant handle force that does not exceed 100 pounds of force at all pressures up to 3,000 psi, it is necessary to maintain a constant pre-charge pressure of approximately two times atmospheric pressure (or about 30 psi absolute pressure). As the pump pressure from the
main cylinder 209 increases in the target volume, the small amount of remaining pressurized air in the dead space (i.e., volume between thepiston 202 and the bottom of thecylinder 201 at the end of the stroke, plus anycheck valve 328 volume) expands to a moderate pre-charge pressure during the upstroke. This pressurized air, combined with the added pressurized air of the pre-charger, creates an undesirable variation in pre-charge pressure in themain cylinder 209 prior to the main compression stroke. As pressure in the target volume increases, the remaining pressure in the dead space increases, and this increases the pre-charge pressure for the next power stroke, which alters the profile of the rigid linkage system resulting in increased force required on thehandle 205 during the power stroke. To eliminate this problem, arelief valve 330 is added to the top 331 of thepre-charge cylinder 312 as shown inFIG. 17 . Therelief valve 330 has a spring loaded ball seal that vents to atmosphere through aport 332 when the internal pre-charge pressure exceeds a predefined limit (approximately two times atmospheric pressure or about 30 PSI absolute pressure). Thisrelief valve 330 maintains a constant pre-charge pressure in the main cylinder prior to the power stroke and it also reduces the force required during the up-stroke (pre-charge stroke) by relieving any excess pre-charge pressure above that required to pre-charge the main cylinder. - While the embodiments disclosed herein have been described as air pumps, it should be noted that the disclosed pumps may be used to pump others gases or fluids as needed or desired, and that such uses shall fall within the scope of the present disclosure or appended claims. It is intended that equivalents of the disclosed exemplary embodiments and methods shall fall within the scope of the present disclosure or appended claims. It is intended that the disclosed exemplary embodiments and methods, and equivalents thereof, may be modified while remaining within the scope of the present disclosure or appended claims.
- For purposes of the present disclosure and appended claims, the phrase “connected . . . to” shall denote a connection between two objects either directly or through some intermediate object or member.
- For purposes of the present disclosure and appended claims, the conjunction “or” is to be construed inclusively (e.g., “a dog or a cat” would be interpreted as “a dog, or a cat, or both”; e.g., “a dog, a cat, or a mouse” would be interpreted as “a dog, or a cat, or a mouse, or any two, or all three”), unless: i) it is explicitly stated otherwise, e.g., by use of “either . . . or”, “only one of . . . ”, or similar language; or ii) two or more of the listed alternatives are mutually exclusive within the particular context, in which case “or” would encompass only those combinations involving non-mutually-exclusive alternatives.
- For purposes of the present disclosure or appended claims, the words “comprise”, comprising”, “have”, “having”, “include”, “including”, and so on shall be construed as being open-ended, e.g., “including” shall be construed as “including but not limited to.”
Claims (18)
1. An air pump, comprising:
a main cylinder having a first end and a second end;
a main piston reciprocably movable within the main cylinder and defining a compression volume within the main cylinder between the main piston and the first end of the main cylinder;
a piston rod connected to the main piston and extending along the main cylinder towards the second end of the main cylinder;
a linkage configured to move the main piston within the main cylinder and to generate pressure in the compression volume during a compression stroke, the linkage having ends pivotably connected to the main cylinder and to the piston rod; and
a pre-charger having a pre-charger piston movable within a pre-charger cylinder, the pre-charger piston being connected to the linkage to move within the pre-charger cylinder when the main piston moves within the main cylinder, the pre-charger generating pressure to augment operation of the main piston and main cylinder.
2. The air pump of claim 1 , wherein the pre-charger cylinder is laterally offset from the main cylinder.
3. The air pump of claim 1 , wherein the pre-charger piston is configured to have a stroke length less than a stroke length of the main piston.
4. The air pump of claim 1 , wherein the pre-charger cylinder is connected to the main cylinder by a valved connection operable to increase pressure in a main cylinder during an upstroke of the main piston.
5. The air pump of claim 4 , wherein the valved connection comprises a check valve connected to the first end of the main cylinder.
6. The air pump of claim 4 , wherein the valved connection comprises a port in the pre-charger cylinder, a tube connected to the port and extending towards the first end of the main cylinder and check valve connected to the tube and to the main cylinder.
7. The air pump of claim 1 , further comprising a pressure relief valve configured to regulate pressure in the pre-charger cylinder.
8. The air pump of claim 7 , wherein the pressure relief valve is set to vent excess pressure in the pre-charger cylinder above about two times atmospheric pressure.
9. The air pump of claim 7 , wherein the pressure relief valve is set to vent excess pressure in the pre-charger cylinder above about 30 psia.
10. The air pump of claim 1 , wherein the pre-charger cylinder comprises a hole through which air is expelled during a downward stroke of the pre-charger piston.
11. The air pump of claim 1 , further comprising a check valve configured to transfer atmospheric pressure across the pre-charger piston to replenish the air supply in an upper portion of the pre-charger cylinder.
12. The air pump of claim 11 , wherein the check valve comprises an o-ring seal on the pre-charger piston that is movable to open a bypass channel through the pre-charger piston.
13. The air pump of claim 12 , wherein pre-charger piston comprises an o-ring groove dimensioned wider than the o-ring, and wherein the o-ring is slidable within the o-ring groove to open the bypass channel on a downward stroke and to close the bypass channel on an upward stroke.
14. The air pump of claim 1 , wherein the linkage comprises a handle and the pre-charger comprises a piston rod connected to the pre-charger piston and to the handle.
15. The air pump of claim 1 , wherein the pressure in the main cylinder generated by the pre-charger is maintained substantially constant.
16. The air pump of claim 1 , wherein the linkage comprises first, second, third and fourth members.
17. The air pump of claim 1 , wherein the diameter of the pre-charger cylinder is greater than a diameter of the main cylinder
18. The air pump of claim 1 , wherein the air pump is configured as a hand pump.
Priority Applications (1)
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US13/356,544 US20120152108A1 (en) | 2006-08-12 | 2012-01-23 | Air pump |
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US11/464,192 US7637203B2 (en) | 2006-08-12 | 2006-08-12 | Air pump |
US12/648,157 US20100150758A1 (en) | 2006-08-12 | 2009-12-28 | Air pump |
US13/356,544 US20120152108A1 (en) | 2006-08-12 | 2012-01-23 | Air pump |
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US12/648,157 Continuation-In-Part US20100150758A1 (en) | 2006-08-12 | 2009-12-28 | Air pump |
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US20120152108A1 true US20120152108A1 (en) | 2012-06-21 |
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US13/356,544 Abandoned US20120152108A1 (en) | 2006-08-12 | 2012-01-23 | Air pump |
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Cited By (1)
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US20150256663A1 (en) * | 2014-03-05 | 2015-09-10 | Honda Motor Co., Ltd. | Information terminal |
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US2673521A (en) * | 1951-11-05 | 1954-03-30 | New York Air Brake Co | Actuating means for hydraulic motors |
US5807078A (en) * | 1996-05-24 | 1998-09-15 | Chen; Chiang Pei | Hand air pumps |
-
2012
- 2012-01-23 US US13/356,544 patent/US20120152108A1/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2673521A (en) * | 1951-11-05 | 1954-03-30 | New York Air Brake Co | Actuating means for hydraulic motors |
US5807078A (en) * | 1996-05-24 | 1998-09-15 | Chen; Chiang Pei | Hand air pumps |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150256663A1 (en) * | 2014-03-05 | 2015-09-10 | Honda Motor Co., Ltd. | Information terminal |
US9420086B2 (en) * | 2014-03-05 | 2016-08-16 | Honda Motor Co., Ltd. | Information terminal |
US9800709B2 (en) | 2014-03-05 | 2017-10-24 | Honda Motor Co., Ltd. | Information terminal |
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