EP1803894B1 - Pneumatic motor - Google Patents
Pneumatic motor Download PDFInfo
- Publication number
- EP1803894B1 EP1803894B1 EP07004290.8A EP07004290A EP1803894B1 EP 1803894 B1 EP1803894 B1 EP 1803894B1 EP 07004290 A EP07004290 A EP 07004290A EP 1803894 B1 EP1803894 B1 EP 1803894B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- engine
- air
- piston
- canister
- spring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63H—TOYS, e.g. TOPS, DOLLS, HOOPS OR BUILDING BLOCKS
- A63H29/00—Drive mechanisms for toys in general
- A63H29/10—Driving mechanisms actuated by flowing media
- A63H29/16—Driving mechanisms actuated by flowing media by steam or compressed air
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
- F01B17/00—Reciprocating-piston machines or engines characterised by use of uniflow principle
- F01B17/02—Engines
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/34—Ultra-small engines, e.g. for driving models
Definitions
- the present invention relates to fluid engines and, more particularly, to pneumatic engines adapted for use in toys such as aeroplanes and wheeled vehicles, including toy cars, trucks and trains.
- the invention is, particularly, directed to a piston-operated pneumatic engine.
- One prior art relative thereto is that of U. S. Patent No. 4,329,806 (1982) to Akiyama , entitled Fluid Engine, and the engine of an unpatented compressed air operated model aeroplane sold in the United Kingdom in or about 1990 known as the Jonathan, utilizing a so-called Z- model engine.
- Akiyama differs, from that of the present invention in a number of material respects, these including differences in the respective input and exhaust mechanisms and in the relationship of the engine piston to the air inlet means to the interior of the engine cylinder. More specifically, Akiyama does not teach or indicate the possibility of a spring enhanced piston action, much less one for providing pressurized air input control to the engine cylinder.
- the same constitutes a direct predecessor of the instant invention which, however, differs therefrom in a number of respects and as such provides a far less efficient pneumatic engine for use with toy vehicles such as an aeroplane.
- the Jonathan has two distinct modes of operation, one a high pressure mode when the air tank or air pressure canister thereof is at high pressure and a second mode when the air canister is at low pressure. Such a distinction between high and low pressure operations does not exist in the present invention.
- the Jonathan employs a piston diaphragm which constitutes the primary air input control means of that system.
- the present system employs a one-way check valve which selectively co-acts with the piston to control air flow through the system intake manifold.
- the Jonathan possesses two different exhaust channels, one in the lower cylinder housing and the other in the upper cylinder housing.
- the instant system employs a single plurality of air exhaust apertures, all situated in the upper or proximal region of the cylinder housing.
- the Jonathan does not afford efficient use of compressed air stored within the inflatable air canister and, as such, cannot achieve a comparable period of operation to that of the present invention. That is, to maintain operation of the system when the canister air pressure falls below a certain level, requires a distinct mode of engine operation during intervals of reduced pressure.
- the Jonathan like the instant invention, makes use of a spring to enhance performance of the engine piston, the length and radius of the spring differ materially from that of the invention. Thereby, the Jonathan cannot optimally use the potential energy resident in the compressed air as it passes through the intake manifold into the engine cylinder housing. Also, the spring itself cannot contribute to system deficiency in the manner of the present invention.
- the present invention may thereby be appreciated as a continuation of this process of development of compressed air and expansion pneumatic engines usable with a variety of toy vehicles including toy aeroplanes.
- US-A-4 472 996 describes a fluid propulsion device for toys including a housing with a cylinder located thereon.
- a pressurized fluid reservoir connects to the cylinder via a value.
- EP-A-0 289 806 there is described a fluid-operated miniature engine operated by an expanding gaseous fluid.
- the engine comprises a cylinder, a piston and an inlet value.
- An air canister is compled with a chamber, which is in fluid communication with the cylinder, via a fluid line.
- the within invention relates to a pneumatic compressed air engine for toy vehicles according to claim 1.
- the engine includes a selectably inflatable air canister and an intake manifold having an engine air inlet in fluid communication with said air canister, the inlet including means for providing compressed air to said canister through the manifold.
- the pneumatic engine also includes a cylinder housing which is defined by distal and proximal regions thereof, an inlet in fluid communication with said engine air inlet and, at said proximal region, a plurality of air exhaust apertures.
- the engine further includes a one-way check valve including a proximal element, reciprocally situated at least partially within said engine air inlet, of the cylinder housing, the check valve residing in a normally closed position relative to the inlet.
- the engine further includes a piston slidably mounted along a longitudinal axis of said cylinder housing in a fluid-tight relationship to internal circumferential region walls of the distal region of the cylindrical housing.
- the piston includes an axial member projecting distally toward said cylinder housing inlet and proportioned in diameter for insertion thereunto. Said piston exhibits a substantially concave proximal surface.
- the pneumatic engine also includes a piston spring mounted about said axial member of said piston and having a length greater than said axial member. Thereby, at a distal end thereof, said piston spring exhibits a length sufficient to effect selectable contact with the proximal element of said check valve during intervals of high pressure between said piston and said distal cylinder housing.
- the engine also includes a connecting rod having a distal end proportioned for complemental non-rigid mechanical interface with said proximal surface of the piston.
- An eccentric is rotationally mounted to an engine power delivery shaft, said eccentric rotatably secured to a proximal end of said connecting rod, in which rotation of said eccentric by said rod transmits angular momentum to said system power shaft. Resultingly, reciprocation of said connecting rod by the eccentric will increase pressure between a distal side of said piston and enclosed internal portions of said distal cylinder housing, compressing said piston spring against said proximal element of said check valve. Thereby, potential energy isimparted to both said spring and the compressed air within said cylinder.
- said proximal element of said check valve will urge open relative to said inlet of said of said cylinder housing, thereby effecting a brief high pressure input of compressed air from said canister, through said intake manifold into said distal region of the cylindrical housing. Said high pressure air input will thereby initiate an expansion of said piston spring and movement of the piston toward said proximal region of said cylinder housing, this causing reiterative cycles of reciprocation of said piston, connecting rod, cam and engine power shaft.
- the piston is returned to its zero or distal-most position b angular inertia from the cam and power shaft.
- a selectably inflatable compressed air canister 10 which is in the nature of a resilient polymeric plastic bottle such as the type of a two or three liter soda bottle.
- the canister 10 will have a capacity of about 2.5 liters with the range thereof preferably between 2 and 3 liters.
- the canister 10, the geometry of which follows the aerodynamics of the toy vehicle that it is to power, is filled through a one-way check valve 12, which includes a proximal ball 14 situated within channel 16 of intake manifold 18.
- the check valve will optionally include a distal ball 20 which communicates with a proximal ball 14 through valve spring 22.
- the air canister 10 is filled with pressurized air by pumping through check valve 12 which in turn causes distal ball 20 of the check valve 12 to compress along the axis of spring 22 in the direction of the proximal ball 14.
- Spring 22 will compress sufficiently to permit passage of air through air aperture 26 of a distal part of channel 16 and therefrom into a channel 24 from which the air enters the air canister 10 for eventual usage with the pneumatic engine in the manner set forth below.
- distal ball 20 will seal against the aperture 26 of the intake manifold 18 thereby providing a tight fluid seal of the compressed air in canister 10.
- the intake manifold 18 also extends to the right to form a portion of the a canister cap 18a, which potion is secured to a canister neck 29 of canister 10 by means of a retaining cap bracket 28.
- a circumferential elastomeric gasket 30 Provided between the canister neck 29 and the cap 18a of intake manifold 18 is a circumferential elastomeric gasket 30.
- retaining cap bracket 28 and neck 29 of the canister 10 are both secured within an engine bracket 32 which is also secured to a proximal cylinder housing 34 through the use of a mounting screw 36. Further, the engine assembly is attached to air canister 10 by means of the intake manifold 18 and retaining cap 28.
- bracket 32 is attached to upper cylinder 34 with screw 36 and on an opposite end of bracket radial ring 32a, that is, to part of engine bracket 32. Radial ring 32 is held between vertical wall 10a or air canister 10 and retaining cap 28. The attachment of this engine bracket 32 is crucial in eliminating vibration and impact forces during normal usage of the vehicle.
- a main engine shaft 38 is, through bearings 40 and 42, secured to a cam 44. (See also Figs. 2A to 2C ). Further, through said bearings 40 and 42, the main shaft 38 is rotationally secured to the proximal cylinder housing 34. Accordingly, shaft 38 rotates within the left hand part of proximal cylinder housing 34 and cam 44 rotates thereupon.
- the cam 44 is provided with a cam shaft 46, the operation of which is more fully described below.
- a propeller adapter 48 which is journalled upon main shaft 38. Thereon is mounted a nose cone adapter 50 over which the propeller of a model aircraft may be secured.
- cam shaft 46 The position of cam shaft 46 relative to the proximal cylinder housing 34 which is shown in Fig. 1 is herein referred to as the zero degree position of the cam. At this rotational position of the cam 44 and cam shaft 46, connecting rod 52 and piston 54 are at their lowest, that is, distal-most position relative to the main shaft 38 of the system.
- the operation of cam 44 and connecting rod 52 relative to piston 54 may be more fully appreciated with reference to the sequential views of Figs. 2A, 2B and 2C . These figures comprise radial cross-sectional views taken in the direction of Line 2B-2B of Fig. 1 .
- the position of the engine of Fig. 1 shown in Fig. 2B is the point of greatest extension of connecting rod 52 and piston 54 relative to the main engine shaft 38 upon which cam 44 rotates.
- Fig. 2A a position of the connecting rod 52 relative to the zero position of Fig. 2B which is 15 degrees before the zero position.
- the same would comprise the so-called 345 degree position, that is, a downstroke position of the engine, while the position of the connecting rod 52 and cam 44 shown in Fig. 2C would constitute the 15 degree, that is, an upstroke position of the engine.
- the significance of these rotational cam positions is further set forth below.
- connecting rod 52 is provided with a substantially spherical bottom surface 58 which fits against a female spherical radius 60 of piston 54.
- connecting rod 52 is not attached to the piston 54 but rather simply mates against it through a low friction engagement which exists between spherical surface 58 of connecting rod 52 and female spherical radius 60 of piston 54.
- each rotation of cam 44 caused by rotation of main shaft 38, will cause connecting rod 52, mounted upon said cam shaft 46, to effect a net vertical linear, that is, up-and-down motion of piston 52 relative to main shaft 38 of 0.32 inches, i. e., approximately 8.5 millimeters.
- the power stroke of the instant engine effected by the low frictionless action between the cam 44 and cam shaft 46, on the one hand, and male spherical surface 58 of connecting rod 52 and female spherical surface 60 of piston 54, on the other hand, is that of about 8.5 millimeters.
- the engine cylinder housing includes said proximal housing 34 and a lower or distal housing 56. It is the distal housing 56 of the cylinder housing and a cylinder inlet 62 (see Fig. 3 ) which is in fluid communication with the inlet 16 of the intake manifold 18. The distal cylinder housing 56 is seated upon asealing O-ring 64 which thereby sits upon the intake manifold 18.
- piston 54 is slidably mounted along a longitudinal axis of the distal cylinder housing 56 and assures a fluid tight relationship between the piston and the internal circumferential walls of said distal housing 56. See Fig. 3 .
- the piston 54 includes an axial member 68 which projects distally toward said cylinder housing inlet 62 and is proportioned in diameter for insertion thereunto.
- a piston spring 70 mounted about said axial member 68 is a piston spring 70 having an outside diameter which is barely sufficient to clear the cylinder housing inlet 62 and having a length sufficient to effect selectable contact with the proximal ball 14 of the one-way check valve within the intake manifold 18.
- Spring 70 plays a special role in the function of the present pneumatic engine by which there is provided to the engine much of its power. More particularly, as piston 54 moves downward within distal cylinder housing 56, the spring 70 will, as is shown in Fig.
- proximal ball 14 which, prior to such contact, is held against a generally conical surface 72 at the entrance of the cylinder housing inlet 62. Prior to such spring contact, proximal ball 14 is held against conical surface 72 by reason of the air pressure against the distal side 56a of the ball 14 from the air canister 10 passing through channels 24 and 16 of the intake manifold 18. This is the condition which is shown in the views of Figs. 4 through 7 , more fully described below.
- spring 70 is only about one millimeter longer than the minimum distance required to open ball 14, only the downward-most position of piston 54 and, with it, of axial member 68 will effect an opening of the ball 14 relative to conical surface 72 of only one millimeter (in vertical linear terms), thereby allowing air to pass about the sides of ball 14 and into the distal cylinder housing 56.
- This process will enable air to pass about the spring 70 through inlet 62 as is indicated by arrows 76 in Fig. 3 .
- air pressure will quickly equalize around ball 14 creating high pressure within the lowermost part of the cylinder housing 56, thus initiating the upward stroke of the piston 54 and connecting rod 52, causing skirt 67 of piston seal to expand radially against walls of said housing 56.
- spring 70 an important function of spring 70, accomplished by careful selection of the spring rate thereof, is that the expansion of spring 70 against ball 14, prior to air pressure equalization about the ball permits a longer interval of compressed air from the air canister to enter the lowest part of the cylinder, than that existent in prior art compressed air engines. This results in a more powerful engine stroke. Further, by selection of a suitable spring constant, spring 70 will expand powerfully against ball 14 upon the initiation of the pressure stroke.
- Fig. 5 Shown in Fig. 5 is the point of maximum height, that is, the top of the 8.5 millimeter stroke of the engine which corresponds to the point of lowest air pressure within distal cylinder housing 56. At that point, piston seal 66 will pass exhaust apertures 78 permitting escape of air from cylinder housing 56 thereby creating a relative vacuum therewith. This escaping air is shown by arrows 80.
- the power of the downstroke of the piston derives from the angular inertia of the propeller which, during a period of low cylinder pressure, is transmitted through the power shaft to the piston 54 and to the piston spring 70 during which potential energy is imparted to both said spring and to compressed air within distal cylinder housing 56.
- power for the upward stroke of the piston derives from a combination of the mass and energy of the compressed air input and the release of potential energy within piston spring 70 as it pushes off of ball 14 at the beginning of the expansion process which is shown in Fig. 4 .
- the one way check valve keeps the supply of air from the air canister 10 closed for all but a brief interval during which the spring force of piston spring 70, less the spring force of one way check valve spring 22, overcomes the air pressure against surface 56a of ball 14 of the check valve.
- the spring force and spring rate of piston spring 70 as well as the narrow clearance of less than a millimeter between the outside diameter of the spring and the cylinder inlet 20, taken with the conical geometry 72 of housing inlet 62, all co-act to provide a reiterating high pressure air inlet of suitable duration, thereby initiating a process of engine expansion and compression respectively using the potential energy stored within the air canister 10 and spring 70.
- Fig. 9 is a schematic view showing the location of the entire engine assembly, as above described, and air canister 10, relative to fuselage 76, main wing 78 and propeller 80 of a model airplane equipped with the present inventive pneumatic engine.
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Description
- The present invention relates to fluid engines and, more particularly, to pneumatic engines adapted for use in toys such as aeroplanes and wheeled vehicles, including toy cars, trucks and trains. The invention is, particularly, directed to a piston-operated pneumatic engine. One prior art relative thereto is that of
U. S. Patent No. 4,329,806 (1982) to Akiyama , entitled Fluid Engine, and the engine of an unpatented compressed air operated model aeroplane sold in the United Kingdom in or about 1990 known as the Jonathan, utilizing a so-called Z- model engine. - Addressing, firstly, the above reference to Akiyama, it differs, from that of the present invention in a number of material respects, these including differences in the respective input and exhaust mechanisms and in the relationship of the engine piston to the air inlet means to the interior of the engine cylinder. More specifically, Akiyama does not teach or indicate the possibility of a spring enhanced piston action, much less one for providing pressurized air input control to the engine cylinder.
- With respect to the Jonathan device known in the United Kingdom, the same constitutes a direct predecessor of the instant invention which, however, differs therefrom in a number of respects and as such provides a far less efficient pneumatic engine for use with toy vehicles such as an aeroplane. More particularly, the Jonathan has two distinct modes of operation, one a high pressure mode when the air tank or air pressure canister thereof is at high pressure and a second mode when the air canister is at low pressure. Such a distinction between high and low pressure operations does not exist in the present invention.
- Further, the Jonathan employs a piston diaphragm which constitutes the primary air input control means of that system. In distinction, the present system employs a one-way check valve which selectively co-acts with the piston to control air flow through the system intake manifold. Further, the Jonathan possesses two different exhaust channels, one in the lower cylinder housing and the other in the upper cylinder housing. In distinction, the instant system employs a single plurality of air exhaust apertures, all situated in the upper or proximal region of the cylinder housing.
- More generally, the Jonathan does not afford efficient use of compressed air stored within the inflatable air canister and, as such, cannot achieve a comparable period of operation to that of the present invention. That is, to maintain operation of the system when the canister air pressure falls below a certain level, requires a distinct mode of engine operation during intervals of reduced pressure.
- While the Jonathan, like the instant invention, makes use of a spring to enhance performance of the engine piston, the length and radius of the spring differ materially from that of the invention. Thereby, the Jonathan cannot optimally use the potential energy resident in the compressed air as it passes through the intake manifold into the engine cylinder housing. Also, the spring itself cannot contribute to system deficiency in the manner of the present invention.
- It is noted that the use of compressed air power as a motive force for model aeroplanes and model vehicles has, in one form or another, existed in the art since approximately 1920. In such devices, so-called air motors which were constructed from brass and employed a three-cylinder arrangement for purposes of balance. The limiting factor in this technology was the air reservoir which, prior to the advent of contemporary plastics, was of necessity metallic. Such metal reservoirs, while having significant weight relative to the weight of the model aeroplane also did not possess properties of elasticity and resilience resident in modem plastics as, for example, exists today with two or three liter soda bottle. Accordingly, with the advent of a lightweight plastic soda bottle, a practical air container or canister, for use in a compressed air or pneumatic power plant for a so-called fluid expansion engine appeared. Thereby, the above-referenced invention of Akiyama marketed by Tome Kogyo Company of Japan and the Jonathan device with its Z-engine became possible.
- The present invention may thereby be appreciated as a continuation of this process of development of compressed air and expansion pneumatic engines usable with a variety of toy vehicles including toy aeroplanes.
-
US-A-4 472 996 describes a fluid propulsion device for toys including a housing with a cylinder located thereon. A pressurized fluid reservoir connects to the cylinder via a value. - In
EP-A-0 289 806 there is described a fluid-operated miniature engine operated by an expanding gaseous fluid. The engine comprises a cylinder, a piston and an inlet value. An air canister is compled with a chamber, which is in fluid communication with the cylinder, via a fluid line. - The within invention relates to a pneumatic compressed air engine for toy vehicles according to claim 1. The engine includes a selectably inflatable air canister and an intake manifold having an engine air inlet in fluid communication with said air canister, the inlet including means for providing compressed air to said canister through the manifold. The pneumatic engine also includes a cylinder housing which is defined by distal and proximal regions thereof, an inlet in fluid communication with said engine air inlet and, at said proximal region, a plurality of air exhaust apertures. The engine further includes a one-way check valve including a proximal element, reciprocally situated at least partially within said engine air inlet, of the cylinder housing, the check valve residing in a normally closed position relative to the inlet. The engine further includes a piston slidably mounted along a longitudinal axis of said cylinder housing in a fluid-tight relationship to internal circumferential region walls of the distal region of the cylindrical housing. The piston includes an axial member projecting distally toward said cylinder housing inlet and proportioned in diameter for insertion thereunto. Said piston exhibits a substantially concave proximal surface. The pneumatic engine also includes a piston spring mounted about said axial member of said piston and having a length greater than said axial member. Thereby, at a distal end thereof, said piston spring exhibits a length sufficient to effect selectable contact with the proximal element of said check valve during intervals of high pressure between said piston and said distal cylinder housing. The engine also includes a connecting rod having a distal end proportioned for complemental non-rigid mechanical interface with said proximal surface of the piston. An eccentric is rotationally mounted to an engine power delivery shaft, said eccentric rotatably secured to a proximal end of said connecting rod, in which rotation of said eccentric by said rod transmits angular momentum to said system power shaft. Resultingly, reciprocation of said connecting rod by the eccentric will increase pressure between a distal side of said piston and enclosed internal portions of said distal cylinder housing, compressing said piston spring against said proximal element of said check valve. Thereby, potential energy isimparted to both said spring and the compressed air within said cylinder. As such, at a maximum of distal reciprocation, said proximal element of said check valve will urge open relative to said inlet of said of said cylinder housing, thereby effecting a brief high pressure input of compressed air from said canister, through said intake manifold into said distal region of the cylindrical housing. Said high pressure air input will thereby initiate an expansion of said piston spring and movement of the piston toward said proximal region of said cylinder housing, this causing reiterative cycles of reciprocation of said piston, connecting rod, cam and engine power shaft. The piston is returned to its zero or distal-most position b angular inertia from the cam and power shaft.
- It is an object of the present invention to provide an improved compressed air expansion engine having particular use as a power source for toy vehicles.
- It is another object to provide an inflatable pneumatic engine for toy vehicles having improved performance characteristics of stability, power, and flight duration over compressed air engines heretofore known in the art.
- It is a further object to provide a pneumatic engine of the above type that can be manufactured through the use of lightweight non-molded plastic components.
- It is a yet further object of the invention to provide a compressed air engine of the above type which can be economically manufactured and which is far more durable than such systems heretofore known in the art.
- The above and yet other objects and advantages of the present invention will become apparent from the hereinafter set forth Brief Description of the Drawings and Detailed Description of the Invention.
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Fig. 1 is a cross-sectional view taken through the longitudinal centers of the main engine shaft, connecting rod, and piston of the present pneumatic engine, in which the cam thereof is at a zero degree position. -
Fig. 2A thru 2C are sequential conceptual views showing he principles of co-action of the cam connecting rod and piston, in whichFig. 2B is taken along Line 2B-2B ofFig. 1 . -
Fig. 3 is a fragmentary view ofFig. 1 showing that portion of the present engine including the piston, connecting rod, cylinder and intake manifold assemblies. -
Fig. 4 is a view, sequential to the view ofFig. 1A showing the piston and connecting rod location at a twenty degree position relative to the fixed engine bracket. -
Fig. 5 is a view sequential to that ofFig. 3 and 4 showing the piston at its maximum height and the cylinder at its lowest atmospheric pressure, this with said cam at a 180 degree position relative to the engine bracket, the same representing the end of the up stroke and beginning of the down stroke. -
Fig. 6 is a schematic view sequential to the views ofFigs. 3 to 5 showing the cam at a rotational position of about 350 degrees. -
Fig. 7 is view sequential to the view ofFig. 6 showing the rotational cam position at about 355 degrees, that is, the first point of contact of the proximal element of the check valve by the piston spring. -
Figs. 8 is a view sequential to the view ofFig. 7 showing the completion of one engine cycle. As such,Fig. 8 indicates the piston and check valve position an instant before that of the view ofFig. 3 . -
Fig. 9 is a schematic view showing the location of the engine assembly and compressed air canister relative to a vertical axial cross-section of a model aeroplane. - With reference to the schematic view of
Fig. 1 , there is shown a selectably inflatablecompressed air canister 10 which is in the nature of a resilient polymeric plastic bottle such as the type of a two or three liter soda bottle. In one embodiment of the invention, thecanister 10 will have a capacity of about 2.5 liters with the range thereof preferably between 2 and 3 liters. Thecanister 10, the geometry of which follows the aerodynamics of the toy vehicle that it is to power, is filled through a one-way check valve 12, which includes aproximal ball 14 situated withinchannel 16 ofintake manifold 18. The check valve will optionally include adistal ball 20 which communicates with aproximal ball 14 throughvalve spring 22. Theair canister 10 is filled with pressurized air by pumping throughcheck valve 12 which in turn causesdistal ball 20 of thecheck valve 12 to compress along the axis ofspring 22 in the direction of theproximal ball 14.Spring 22 will compress sufficiently to permit passage of air throughair aperture 26 of a distal part ofchannel 16 and therefrom into achannel 24 from which the air enters theair canister 10 for eventual usage with the pneumatic engine in the manner set forth below. Except during pumping,distal ball 20 will seal against theaperture 26 of theintake manifold 18 thereby providing a tight fluid seal of the compressed air incanister 10. - The
intake manifold 18 also extends to the right to form a portion of the acanister cap 18a, which potion is secured to a canister neck 29 ofcanister 10 by means of a retainingcap bracket 28. Provided between the canister neck 29 and thecap 18a ofintake manifold 18 is a circumferentialelastomeric gasket 30. It is noted that retainingcap bracket 28 and neck 29 of thecanister 10 are both secured within anengine bracket 32 which is also secured to aproximal cylinder housing 34 through the use of a mountingscrew 36. Further, the engine assembly is attached toair canister 10 by means of theintake manifold 18 and retainingcap 28. It is very important that the alignment ofshaft 38 stay stationary, especially in that large forces impacting into, and perpendicular to, the centering of the shaft axis are common during normal usage. To eliminate any movement or excessive forces onintake manifold 18 thebracket 32 is attached toupper cylinder 34 withscrew 36 and on an opposite end of bracketradial ring 32a, that is, to part ofengine bracket 32.Radial ring 32 is held betweenvertical wall 10a orair canister 10 and retainingcap 28. The attachment of thisengine bracket 32 is crucial in eliminating vibration and impact forces during normal usage of the vehicle. - A
main engine shaft 38 is, throughbearings 40 and 42, secured to acam 44. (See alsoFigs. 2A to 2C ). Further, through saidbearings 40 and 42, themain shaft 38 is rotationally secured to theproximal cylinder housing 34. Accordingly,shaft 38 rotates within the left hand part ofproximal cylinder housing 34 andcam 44 rotates thereupon. Thecam 44 is provided with acam shaft 46, the operation of which is more fully described below. - To the left of bearing 40 is shown a propeller adapter 48 which is journalled upon
main shaft 38. Thereon is mounted anose cone adapter 50 over which the propeller of a model aircraft may be secured. - The position of
cam shaft 46 relative to theproximal cylinder housing 34 which is shown inFig. 1 is herein referred to as the zero degree position of the cam. At this rotational position of thecam 44 andcam shaft 46, connectingrod 52 andpiston 54 are at their lowest, that is, distal-most position relative to themain shaft 38 of the system. The operation ofcam 44 and connectingrod 52 relative topiston 54 may be more fully appreciated with reference to the sequential views ofFigs. 2A, 2B and 2C . These figures comprise radial cross-sectional views taken in the direction ofLine 2B-2B ofFig. 1 . The position of the engine ofFig. 1 shown inFig. 2B , is the point of greatest extension of connectingrod 52 andpiston 54 relative to themain engine shaft 38 upon whichcam 44 rotates. - In
Fig. 2A is shown a position of the connectingrod 52 relative to the zero position ofFig. 2B which is 15 degrees before the zero position. As such, the same would comprise the so-called 345 degree position, that is, a downstroke position of the engine, while the position of the connectingrod 52 andcam 44 shown inFig. 2C would constitute the 15 degree, that is, an upstroke position of the engine. The significance of these rotational cam positions is further set forth below. - With further reference to
Figs. 2A through 2C , it is noted that the bottom of connectingrod 52 is provided with a substantiallyspherical bottom surface 58 which fits against a femalespherical radius 60 ofpiston 54. Therein, connectingrod 52 is not attached to thepiston 54 but rather simply mates against it through a low friction engagement which exists betweenspherical surface 58 of connectingrod 52 and femalespherical radius 60 ofpiston 54. - It is noted that each rotation of
cam 44, caused by rotation ofmain shaft 38, will cause connectingrod 52, mounted upon saidcam shaft 46, to effect a net vertical linear, that is, up-and-down motion ofpiston 52 relative tomain shaft 38 of 0.32 inches, i. e., approximately 8.5 millimeters. Accordingly, the power stroke of the instant engine, effected by the low frictionless action between thecam 44 andcam shaft 46, on the one hand, and malespherical surface 58 of connectingrod 52 and femalespherical surface 60 ofpiston 54, on the other hand, is that of about 8.5 millimeters. - In further regard the schematic view of
Fig.1 , it is noted that the engine cylinder housing includes saidproximal housing 34 and a lower ordistal housing 56. It is thedistal housing 56 of the cylinder housing and a cylinder inlet 62 (seeFig. 3 ) which is in fluid communication with theinlet 16 of theintake manifold 18. Thedistal cylinder housing 56 is seated upon asealing O-ring 64 which thereby sits upon theintake manifold 18. - By virtue of a
piston seal 66 and a circumferentialintegral skirt 67 thereof,piston 54 is slidably mounted along a longitudinal axis of thedistal cylinder housing 56 and assures a fluid tight relationship between the piston and the internal circumferential walls of saiddistal housing 56. SeeFig. 3 . - The
piston 54 includes anaxial member 68 which projects distally toward saidcylinder housing inlet 62 and is proportioned in diameter for insertion thereunto. Mounted about saidaxial member 68 is apiston spring 70 having an outside diameter which is barely sufficient to clear thecylinder housing inlet 62 and having a length sufficient to effect selectable contact with theproximal ball 14 of the one-way check valve within theintake manifold 18.Spring 70 plays a special role in the function of the present pneumatic engine by which there is provided to the engine much of its power. More particularly, aspiston 54 moves downward withindistal cylinder housing 56, thespring 70 will, as is shown inFig. 3 , contactproximal ball 14 which, prior to such contact, is held against a generallyconical surface 72 at the entrance of thecylinder housing inlet 62. Prior to such spring contact,proximal ball 14 is held againstconical surface 72 by reason of the air pressure against the distal side 56a of theball 14 from theair canister 10 passing throughchannels intake manifold 18. This is the condition which is shown in the views ofFigs. 4 through 7 , more fully described below. Accordingly, only in the condition shown inFigs.1 ,2B ,3 and8 , that is, in which the cam is at a zero degree position, that is, a maximum piston rod stroke extension, will the spring force ofpiston spring 68, less the spring force ofcheck valve spring 22, be sufficient to overcome the air pressure against distal side 56a ofball 14. This force is calculated by multiplying the air pressure from theair canister 10, that is, approximately 100 pounds per square inch, times the area of thehousing inlet 62, which has a diameter of about 1.7 millimeters. Thereby, the force necessary to accomplish closure ofball 14 againstconical surface 72 andinlet 62 is 0.332 pounds. That is about 151 grams of force. Such opening ofball 14 can only be accomplished at the lowest point of the cam stroke, that is, the zero degree position shown inFigs. 1 ,2B ,3 and8 . - Further, since
spring 70 is only about one millimeter longer than the minimum distance required to openball 14, only the downward-most position ofpiston 54 and, with it, ofaxial member 68 will effect an opening of theball 14 relative toconical surface 72 of only one millimeter (in vertical linear terms), thereby allowing air to pass about the sides ofball 14 and into thedistal cylinder housing 56. This process will enable air to pass about thespring 70 throughinlet 62 as is indicated byarrows 76 inFig. 3 . As this occurs, air pressure will quickly equalize aroundball 14 creating high pressure within the lowermost part of thecylinder housing 56, thus initiating the upward stroke of thepiston 54 and connectingrod 52, causingskirt 67 of piston seal to expand radially against walls of saidhousing 56. - It is noted that an important function of
spring 70, accomplished by careful selection of the spring rate thereof, is that the expansion ofspring 70 againstball 14, prior to air pressure equalization about the ball permits a longer interval of compressed air from the air canister to enter the lowest part of the cylinder, than that existent in prior art compressed air engines. This results in a more powerful engine stroke. Further, by selection of a suitable spring constant,spring 70 will expand powerfully againstball 14 upon the initiation of the pressure stroke. - The same is represented by the transition in piston positions shown between the zero degree cam position of
Fig. 3 and the 20 degree cam position ofFig. 4 , in which skirt 67 remains flush with the walls ofhousing 56, thereby assuring high pressure within said housing during theFig. 4 phase of the engine stroke. It is, accordingly, to be appreciated that the view ofFig. 3 represents both completion of a downward stroke and the initiation of an upward stroke in which the downward stroke is completed when the spring force againstball 14 exceeds 151 grams. - The beginning of the upward motion of
piston 54 is shown inFig. 4 , this corresponding to the twenty-degree position of the cam. Therein, high pressure withindistal cylinder housing 56 piston moves thecylinder 54 upward and, with it, connectingrod 52, thus furthering the rotation ofcam 44 and, with it,main shaft 38. During this entire period,ball 14 is closed whilecheck valve spring 22, which connectsballs piston spring 70 completes its push off fromproximal ball 14 of thecheck valve 16. - Shown in
Fig. 5 is the point of maximum height, that is, the top of the 8.5 millimeter stroke of the engine which corresponds to the point of lowest air pressure withindistal cylinder housing 56. At that point,piston seal 66 will passexhaust apertures 78 permitting escape of air fromcylinder housing 56 thereby creating a relative vacuum therewith. This escaping air is shown byarrows 80. - After the maximum stroke height of
Fig. 5 is accomplished, the angular inertia from the aircraft propeller, is transmitted, throughshaft 38, tocam 44, to connectingrod 52 and topiston 54. This will, as is shown in the transition fromFig. 5 to Fig. 6 , cause downward motion of the rod and piston. As this occurs, air pressure withindistal cylinder housing 56 will increase as will potential energy withinspring 70. This process continues causingspring 70 to contactball 14 at about 350 degrees. At this point,skirt 67 ofseal 66 is not sealed against the wall ofhousing 56, thereby allowing air to leak between said skirt and walls ofhousing 56. In the view ofFig. 7 which corresponds to a cam position of 355 degrees, a point of near maximum pressure withindistal housing 56 is accomplished. The 360 degrees or zero degrees position is shown in the view ofFig. 8 . At that point, as above described with reference toFig. 3 , the spring force ofspring 70 will overcome the 151 grams of force applied by the compressed air input fromcanister 10 against the distal surface 56a ofball 14. - Summarizing this action, the power of the downstroke of the piston derives from the angular inertia of the propeller which, during a period of low cylinder pressure, is transmitted through the power shaft to the
piston 54 and to thepiston spring 70 during which potential energy is imparted to both said spring and to compressed air withindistal cylinder housing 56. Conversely, power for the upward stroke of the piston derives from a combination of the mass and energy of the compressed air input and the release of potential energy withinpiston spring 70 as it pushes off ofball 14 at the beginning of the expansion process which is shown inFig. 4 . Therein, the one way check valve, as actuated bypiston spring 70, keeps the supply of air from theair canister 10 closed for all but a brief interval during which the spring force ofpiston spring 70, less the spring force of one waycheck valve spring 22, overcomes the air pressure against surface 56a ofball 14 of the check valve. The spring force and spring rate ofpiston spring 70, as well as the narrow clearance of less than a millimeter between the outside diameter of the spring and thecylinder inlet 20, taken with theconical geometry 72 ofhousing inlet 62, all co-act to provide a reiterating high pressure air inlet of suitable duration, thereby initiating a process of engine expansion and compression respectively using the potential energy stored within theair canister 10 andspring 70. -
Fig. 9 is a schematic view showing the location of the entire engine assembly, as above described, andair canister 10, relative tofuselage 76,main wing 78 andpropeller 80 of a model airplane equipped with the present inventive pneumatic engine. - While there has been shown and described the preferred embodiment of the instant invention it is to be appreciated that the invention may be embodied otherwise than is herein specifically shown and described and that, within said embodiment, certain changes may be made in the form and arrangement of the parts without departing from the underlying ideas or principles of this invention, as claimed herein.
Claims (4)
- A pneumatic engine, comprising:a) a rechargeable air canister (10) having an opening therein;b) an engine cylinder (34,56); andc) the air canister (10) being rigidly coupled directly to a chamber (18) having an aperture (24) therethrough and an air inlet (26) in fluid communication with said opening in said canister (10), said chamber (18) being also in fluid communication with said engine cylinder (34, 56),wherein
said chamber (18) is rigidly coupled directly to said engine cylinder (34, 56) and is also in fluid communication with a fluid supply such that the rechargeable canister (10) is recharged by passing fluid from the fluid supply, through the chamber (18), and to the rechargeable canister (10). - A pneumatic engine according to claim 1, wherein said engine cylinder (34,56) has an air inlet (62), said air inlet (62) being adapted to allow air to pass from said chamber (18) to said engine cylinder (34,56).
- A pneumatic engine according to claim 2, wherein said engine cylinder (34,56) air inlet (62) has a one-way check valve (14, 22, 72).
- A pneumatic engine according to claim 1, wherein said aperture (24) is adapted to allow high pressure air to be pumped through said chamber (18) and into said air canister (10).
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US8104598P | 1998-04-09 | 1998-04-09 | |
US09/178,595 US6006517A (en) | 1998-04-09 | 1998-10-26 | Pneumatic engine |
PCT/US1999/007645 WO1999053211A1 (en) | 1998-04-09 | 1999-04-07 | Pneumatic engine |
EP99917361A EP1082550B1 (en) | 1998-04-09 | 1999-04-07 | Pneumatic engine |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP99917361A Division EP1082550B1 (en) | 1998-04-09 | 1999-04-07 | Pneumatic engine |
Publications (2)
Publication Number | Publication Date |
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EP1803894A1 EP1803894A1 (en) | 2007-07-04 |
EP1803894B1 true EP1803894B1 (en) | 2018-12-05 |
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ID=38115992
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP07004290.8A Expired - Lifetime EP1803894B1 (en) | 1998-04-09 | 1999-04-07 | Pneumatic motor |
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CN114904284A (en) * | 2021-02-08 | 2022-08-16 | 孙翠颜 | Toy plane |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0151314A1 (en) * | 1984-01-25 | 1985-08-14 | Pewa Technic Ag | Gas-operated motor with a gas supply apparatus |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS57175383A (en) * | 1981-04-24 | 1982-10-28 | Tomy Kogyo Co | Gas working type engine for toy |
IT1214182B (en) * | 1987-05-07 | 1990-01-10 | Caenazzo Alessandro Pasqualott | FLUID MICROMOTOR. |
-
1999
- 1999-04-07 EP EP07004290.8A patent/EP1803894B1/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0151314A1 (en) * | 1984-01-25 | 1985-08-14 | Pewa Technic Ag | Gas-operated motor with a gas supply apparatus |
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