WO1999053211A1

WO1999053211A1 - Pneumatic engine

Info

Publication number: WO1999053211A1
Application number: PCT/US1999/007645
Authority: WO
Inventors: Jeffrey G. Rehkemper; Ronnen Harary
Original assignee: Spin Master Toys, Ltd.; Kownacki, Charles, D.
Priority date: 1998-04-09
Filing date: 1999-04-07
Publication date: 1999-10-21
Also published as: EP1082550A1; EP1082550A4; AU758720B2; EP1082550B1; CA2328067C; CA2328067A1; US6006517A; AU3550499A; HK1037709A1; DE69936301D1; DE69936301T2

Abstract

A fluid engine for use in pneumatically operated toys such as wheeled vehicles or airplanes includes an engine having a fluid input cavity which is in continuous fluid communication with a source of compressed air (10), a fluid delivery cavity which is in continuous communication with a piston cavity bounded by a moveable piston (54) mounted in a cylinder member (56) and which is separated from the fluid input cavity by a wall having a valve opening (62), and exhaust apertures which are separated from the fluid delivery cavity. A valve rod (68) is movably housed to open the valve opening and close the exhaust apertures during the piston's power stroke, and to close the valve opening and open the exhaust opening during the piston's exhaust stroke. The valve rod is operatively connected to a piston to act in synchronism with it by the use of a cam (44) integrally secured to a propeller power shaft.

Description

TITLE: PNEUMATIC ENGINE

BACKGROUND OF THE INVENTION

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. Accordingly, the only

prior art relative thereto known to the inventor 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 modern

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.

SUMMARY OF THE INVENTION

The within invention relates to a pneumatic compressed

air engine for toy vehicles, the engine including 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 is imparted 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.

10

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.

11

BRIEF DESCRIPTION OF THE DRAWINGS

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. 2 A thru 2C are sequential conceptual views

showing he principles of co-action of the cam connecting rod

and piston, in which Fig. 2B is taken along Line 2B-2B of

Fig. 1.

Fig. 3 is a fragmentary view of Fig. 1 showing that

portion of the present engine including the piston, connecting

rod, cylinder and intake manifold assemblies .

12

Fig. 4 is a view, sequential to the view of Fig. 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 of Fig. 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 of

Figs. 3 to 5 showing the cam at a rotational position of about

350 degrees.

13

Fig. 7 is view sequential to the view of Fig. 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 of Fig. 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 of Fig. 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.

14

DETAILED DESCRIPTION OF THE INVENTION

With reference to the schematic view of Fig. 1, there

is shown 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. In one

embodiment of the invention, 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, ^v 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 15

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. Except

during pumping, 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. Provided between the canister neck

29 and the cap 18a of intake manifold 18 is a circumferential

elastomeric gasket 30. It is noted that 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, 16

the engine assembly is attached to air canister 10 by means of

the intake manifold 18 and retaining cap 28. It is very

important that the alignment of shaft 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 on intake manifold 18 the 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. 2 A to 2C). Further,

through said bearings 40 and 42, the main shaft 38 is 17

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.

To the left of bearing 40 is shown 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.

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 18

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.

In Fig. 2 A is shown a position of the connecting rod 52

relative to the zero position of Fig. 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 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. 19

With further reference to Figs. 2 A through 2C, it is

noted that the bottom of connecting rod 52 is provided with

a substantially spherical bottom surface 58 which fits against

a female spherical radius 60 of piston 54. Therein,

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.

It is noted that 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. Accordingly, 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 20

spherical surface 60 of piston 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 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 a sealing O-ring 64 which thereby sits upon the

intake manifold 18.

By virtue of a piston seal 66 and a circumferential

integral skirt 67 thereof, 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. 21

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. 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. 3, contact 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 22

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. Accordingly, only in the condition shown

in Figs. 1, 2B, 3 and 8, that is, in which the cam is at a zero

degree position, that is, a maximum piston rod stroke

extension, will the spring force of piston spring 68, less the

spring force of check valve spring 22, be sufficient to

overcome the air pressure against distal side 56a of ball 14.

This force is calculated by multiplying the air pressure from

the air canister 10, that is, approximately 100 pounds per

square inch, times the area of the housing inlet 62, which has

a diameter of about 1.7 millimeters. Thereby, the force

necessary to accomplish closure of ball 14 against conical

surface 72 and inlet 62 is 0.332 pounds. That is about 151

grams of force. Such opening of ball 14 can only be

accomplished at the lowest point of the cam stroke, that is,

the zero degree position shown in Figs. 1, 2B, 3 and 8. 23

Further, since 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. As this occurs, 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.

It is noted that 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 24

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. 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 of Fig. 4,

in which skirt 67 remains flush with the walls of housing 56,

thereby assuring high pressure within said housing during the

Fig. 4 phase of the engine stroke. It is, accordingly, to be

appreciated that the view of Fig. 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 against ball 14 exceeds 151 grams. 25

The beginning of the upward motion of piston 54 is

shown in Fig. 4, this corresponding to the twenty-degree

position of the cam. Therein, high pressure within distal

cylinder housing 56 piston moves the cylinder 54 upward and,

with it, connecting rod 52, thus furthering the rotation of cam

44 and, with it, main shaft 38. During this entire period, ball

14 is closed while check valve spring 22, which connects balls

14 and 20, remains in an expanded state. Therein, piston

spring 70 completes its push off from proximal ball 14 of the

check 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 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. 26

After the maximum stroke height of Fig. 5 is

accomplished, the angular inertia from the aircraft propeller,

is transmitted, through shaft 38, to cam 44, to connecting rod

52 and to piston 54. This will, as is shown in the transition

from Fig. 5 to Fig. 6, cause downward motion of the rod and

piston. As this occurs, air pressure within distal cylinder

housing 56 will increase as will potential energy within spring

70. This process continues causing spring 70 to contact ball

14 at about 350 degrees. At this point, skirt 67 of seal 66 is

not sealed against the wall of housing 56, thereby allowing air

to leak between said skirt and walls of housing 56. In the

view of Fig. 7 which corresponds to a cam position of 355

degrees, a point of near maximum pressure within distal

housing 56 is accomplished. The 360 degrees or zero degrees

position is shown in the view of Fig. 8. At that point, as

above described with reference to Fig. 3, the spring force of

spring 70 will overcome the 151 grams of force applied by 27

the compressed air input from canister 10 against the distal

surface 56a of ball 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 the

piston spring 70 during which potential energy is imparted to

both said spring and to compressed air within distal 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

within piston spring 70 as it pushes off of ball 14 at the

beginning of the expansion process which is shown in Fig. 4.

Therein, the one way check valve, as actuated by piston

spring 70, keeps the supply of air from the air canister 10

closed for all but a brief interval during which the spring 28

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. 29

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

30THE CLAIMSI claim:

1. A pneumatic engine for toy vehicles, comprising:

(a) a selectably inflatable compressed air

canister;

(b) an intake mamfold, comprising:

an engine air inlet, in fluid communication with said air

canister, the inlet including means for providing compressed

air to said canister through said manifold;

(c) a cylinder housing including:

(i) distal and proximal regions thereof,

(ii) an inlet in fluid commumcation

with said engine air inlet, and

(iii) at said proximal region, a plurality of

air exhaust apertures;

31

(d) a one-way check valve including a proximal

element, reciprocally situated at least partially within said

inlet of said cylinder housing, said check valve residing in a

normally closed position relative to said inlet;

(e) a piston slidably mounted along a longitudinal axis

of said housing in a substantially fluid-tight relationship

relative to internal circumferential walls of said distal region

of said cylindrical housing, said piston including an axial

member projecting distally toward said cylinder housing inlet

and proportioned in diameter for insertion thereinto, said

piston having a substantially concave proximal surface

thereof;

(f) a piston spring mounted about said axial member

of said piston and having a length greater than said axial

member and, thereby, at a distal end thereof, having a length

sufficient to effect selectable contact with a proximally

directed element of said check valve during intervals of high

pressure between said piston and said cylinder housing; 32

(g) a connecting rod having a distal end proportioned

for complemental non-rigid mechanical interface with said

proximal surface of said piston;

(h) an eccentric rotationally mounted to an engine

power delivery shaft, said eccentric rotatable secured to a

proximal end of said connecting rod, in which rotation of said

eccentric by said rod will transmit angular momentum and

force to said system power shaft,

whereby reciprocation of said connecting rod by said

eccentric will increase pressure between a distal side of said

piston and enclosed internal portions of said cylinder housing

and will compress said piston spring against said proximal

element of said check valve, thereby imparting potential

energy to both said spring and compressed air within said

cylinder and, further whereby, at maximum of distal

reciprocation, said proximal element of said check valve will

urge open relative to said inlet of said cylindrical housing,

thereby effecting a brief high pressure input of compressed air 33

from said canister, through said intake manifold and into said

distal region of said cylindrical housing, said high pressure air

input thereby initiating expansion of said piston spring and

movement of said piston toward said proximal region of said

cylinder housing, the same causing reiterative cycles of

reciprocation of said piston, connecting rod, cam, and engine

power shaft.

2. The engine as recited in Claim 1, in which said intake

manifold and air canister comprise means for complemental

positive mechanical securement therebetween which ensures

said fluid communication of said air inlet with said air

canister.

34

3. The engine as recited in Claim 2, in which securement

means include a radial cap of said intake manifold having

thread means for securement to said canister and an

elastomeric seal seated between said intake manifold and said

canister.

4. The engine as recited in Claim 1, in which said piston

comprises:

a piston seal, including a circumferential skirt

proportioned in radius to inner walls of said housing, said seal

integrally dependent from a proximal surface of said piston.

5. A fluid input assembly for a pneumatic engine for toy

vehicles, the assembly comprising:

(a) an inflatable resilient compressed air canister; and

(b) an intake mamfold comprising an external air inlet

comprising means for selectably providing compressed air to

said canister through said manifold. 35

6. The assembly as recited in Claim 5, in which an

interface of said intake manifold and air canister defines

means for complemental positive mechanical securement to

thereby ensure secure fluid communication of said air inlet

with air canister.

7. The assembly as recited in Claim 6, in which said

positive mechanical securement means comprises a radial

bracket of said intake manifold including thread means for

securement to said canister and an elastomeric seal seated at

said interface.

8. The assembly as recited in Claim 6 further comprising:

(c) an air inlet for said pneumatic engine in selectable

fluid communication with said intake manifold.