US3268216A

US3268216A - Charge forming device for internal combustion engines

Info

Publication number: US3268216A
Application number: US456652A
Authority: US
Inventors: Bernard C Phillips
Original assignee: Tillotson Manufacturing Co
Current assignee: Tillotson Manufacturing Co
Priority date: 1965-05-18
Filing date: 1965-05-18
Publication date: 1966-08-23
Anticipated expiration: 1983-08-23

Description

Aug. 23, 1966 B. c. PHILLIPS 3,

CHARGE FORMING DEVICE FOR INTERNAL COMBUSTION ENGINES Original Filed Aug. 20, 1962 5 Sheets-Sheet 1 INVENTOR: Ezmww QFHJLLIPS.

III I Aug. 23, 1966 B. c. PHILLIPS 3,

CHARGE FORMING DEVICE FOR INTERNAL COMBUSTION ENGINES Original Filed Aug. 20, 1962 5 Sheets-Sheet 2 i INVENTOR: s

1523mm ZZPmLIPs.

3, 1966 B. c. PHILLIPS 3,268,216

CHARGE FORMING DEVICE FOR INTERNAL COMBUSTION ENGINES TIE-T7- 115-18 .EERNARU L". PHILLIPS.

United States Patent 3,268,216 CHARGE FORMING DEVICE FOR INTERNAL COMBUSTION ENGINES Bernard C. Phillips, Toledo, Ohio, assignor to The Tillotson Manufacturing Company, Toledo, Ohio, a corporation of Ohio Continuation of application Ser. No. 218,082, Aug. 20,

1962. This application May 18, 1965, Ser. No. 456,652 3 Claims. (Cl. 26169) This is a continuation of my copending application, Serial Number 218,082 filed August 20, 1962, and since abandoned, which is a continuation-in-part application of my application, Serial Number 739,414 filed June 2, 1958, now issued into Patent 3,133,129.

This invention relates to charge forming apparatus or device for supplying a mixture of fuel and air to an internal combustion engine and more especially to a charge forming apparatus embodying a flexible diaphragm adapted to be controlled by aspiration or reduced pressure in a mixing passage for automatically regulating the delivery of fuel from a supply into a reservoir chamber in the charge forming device from which the fuel is conveyed to the mixing passage.

The conventional type of charge forming device embodying a float-actuated fuel control valve arrangement is wholly unsuitable for use with internal combustion engines which are to be operated in positions of tilt or extreme angular positions. Furthermore carburetors or charge forming devices wherein the fuel flow control valve is float-actuated are extremely sensitive to vibrations and hence are prone to deliver an oversupply of fuel when subjected to vibrations during operation.

The present invention embraces a carburetor or charge forming device for delivering or feeding a fuel and air mixture to an internal combustion engine which is effective in substantial positions of tilt to maintain proper delivery of fuel to an engine.

Another object of the invention is the provision of a charge forming device or carburetor of simplified character embodying a diaphragm arranged to be influenced solely by pressures in the mixing passage for controlling the delivery of fuel into the mixing passage.

Another object of the invention is the provision of a diaphragm-type of charge forming device wherein fuel is delivered into the mixing passage through a single outlet and solely by aspiration established through engine operation and with a minimum of differential pressure whereby fuel is effectively delivered into the mixing passage under severe conditions of vibration, substantial tilting of the charge forming device and under a wide range of fuel supply pressures.

Another object of the invention is the provision of a simplified, comparatively small diaphragm-type carburetor having a single fuel delivery orifice from a fuel chamber into the mixing passage whereby the charge forming device has particular utility with internal combustion engines especially of the two cycle type adaptable for operation at substantially constant or governed speeds.

Another object of the invention is the provision of a comparatively small diaphragm-type charge forming device which may be inexpensively manufactured and which finds utility for particular uses such as with engines for operating stone hammers, combustion heaters for vehicles and particularly truck vehicles, special military equipment, engines for chain saws, portable power drilling units, lightweight generator units and similar applications.

Another object of the invention is the provision of a small, compact diaphragm-type carburetor wherein the number of components have been reduced to a minimum whereby a charge forming device of this character may be economically produced.

Another object of the invention is the provision of a compact diaphragm carburetor which during operation is substantially immune to the adverse effects of vibration and which will deliver the proper flow of fuel into the mixing passage under various operating conditions and wherein efiicient atomization and distribution of metered fuel into the mixing passage is attained with a minimum of movable components.

Another object of the invention is the provision of a diaphragm-type of charge forming device wherein fuel is delivered into a mixing passage through a single orifice and solely by aspiration established through engine operation and which may be brought into and maintained in operation under a minimum of reduced pressure effective to establish fuel delivery tothe mixing passage.

Another object of the invention is the provision of a charge forming device embodying a fuel flow control ball valve which is directly controlled by a diaphragm which is extremely sensitive to pressure variations whereby an effective and critical control is maintained over fuel flow into the charge forming device.

A further object of the invention is the provision of an improved lever member and fulcrum arrangement for transmitting movements of the fuel metering diaphragm to a fuel inlet control valve.

Still a further object of the invention is the provision of a combined valve seat and cage or valve guide unit for a fuel inlet control valve of the carburetor.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be [apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

FIGURE 1 is a side elevational view of a form of charge forming device of the invention with air cleaner attached;

FIGURE 2 is a top plan view of the carburetor const-ruction illustrated in FIGURE 1;

FIGURE 3 is a bottom plan view of the arrangement shown in FIGURE 1 with the diaphragm, retaining plate and air cleaner removed;

FIGURE 4 is a longitudinal detail sectional view taken substantially on the line 4-4 of FIGURE 2;

FIGURE 5 is a detail sectional view taken substantially on the line 55 of FIGURE 2;

FIGURE 6 is a detail sectional view taken substantially on the line 6-6 of FIGURE 2;

FIGURE 7 is a fragmentary detail sectional view illustrating a modified form of fuel inlet valve arrangement of the invention;

FIGURE 8 is a fragmentary sectional view illustrating the arrangement with a fixed fuel metering orifice;

FIGURE 9 is a plan view of a form of diaphragm-type carburetor embodying the invention;

FIGURE 10 is a bottom plan view of a portion of the construction shown in FIGURE 9 with the diaphragm and cover plate removed for purposes of illustration;

FIGURE 11 is a transverse sectional view taken substantially on the line 11-11 of FIGURE 9;

FIGURE 12 is a fragmentary detail sectional view illustrating a form of connection between the inlet valve actuating lever and the valve;

FIGURE 13 is a fragmentary detail sectional view illustrating a form of lever connection with a component carried by the diaphragm for positively transmitting movernents of the diaphragm to an inlet valve;

FIGURE 14 is a plan view of the arrangement shown in FIGURE 13;

FIGURE 15 is a fragmentary detail sectional view taken substantially on the line 1515 of FIGURE 10;

FIGURE 16 is a sectional view similar to FIGURE 11 illustrating a combined valve seat and valve guide unit of the invention;

FIGURE 17 is an enlarged detail sectional view taken substantially on the line 17-17 of FIGURE 16, and

FIGURE 18 is a sectional view similar to FIGURE 17 showing a modified form of combined fuel inlet valve seat and valve guide unit.

While the carburetor construction or charge forming device of the invention is particularly adaptable for use in forming mixture charges for an internal combustion engine of the two cycle type, it is to be understood that the charge forming device of the invention may be utilized with four cycle internal combustion engines.

Referring to the drawings in detail and initially to the form of the invention illustrated in FIGURES 1 through 6, the charge forming device or carburetor is inclusive of a body or body member 10 which may be a die casting fashioned of zinc or alloys of zinc and aluminum or other constituents or may be fashioned or molded of resinous plastic which is unaffected by hydrocarbon fuels.

The body 10 is formed with a mixing passage 12 which preferably includes a Venturi configuration 14 into which liquid fuel is delivered for admixing with air admitted through an air inlet 16. While a Venturi embodied in the mixing passage is preferred in order to obtain high air velocity through the mixing passage, it is to be understood that the carburetor may be utilized with small low horsepower engines and heaters and in such instances the Venturi may be dispensed with and the walls of the mixing passage of cylindrical shape.

A disk-type valve 18 providing a throttle control for regulating the rate of admission of the mixture into the engine may be mounted upon a supporting shaft 20 which is journaled in a bore formed in a boss portion 22 of the body, the shaft 20 extending into a bore 24 formed in the carburetor body as particularly illustrated in FIGURE 4, the disk 18 being secured to the shaft 20 by means of a screw 25.

An operating arm 26 is secured to a tenon portion formed on the shaft 20 extending exteriorly of the boss 22. The arm 26 may be provided with a fitting 28 for manipulating the throttle 18, the fitting being adapted for connection with a flexible wire control (not shown) whereby the throttle may be manipulated at a position remote from the carburetor.

The carburetor body 10 is provided with a flange 30 which is adapted to be secured to a boss portion 32 formed on the wall of a crankcase of an engine of the two cycle type or to an intake manifold of an engine of the four cycle type. The flange is secured to the boss 32 by means of bolts 34. An air cleaner 36 may be connected with the air inlet 16 as shown in FIGURES 1 and 2.

The body 10 of the charge forming device is formed with shallow fuel chamber or passage 38 of minimum depth to reduce to a minimum :the amount in the chamber 38. A flexible member, diaphragm or membrane 40 forms one wall of the shallow chamber 38 as shown in FIGURES 4 through 6. An annular gasket 43 is disposed adjacent one face of the flexible diaphragm 40, preferably between the diaphragm and the body 10, to effect a liquid tight seal between the body and the diaphragm. A cover plate 42, which may be formed of sheet metal or of molded resinous plastic or the like, has a peripheral planar portion 44. The planar portion 44, the peripheral region of the diaphragm 40 and the gasket 41 are provided with aligned openings to accommodate securing screws 46 which are threaded into openings 47 formed in the body 10, one of the securing screws being illustrated in FIGURE 5 extending into a threaded opening in the body 10.

The cover or closure plate 42, as shown in FIGURES 4 through 6, is fashioned or formed with a depressed central region or portion providing a space 48 to accommodate movements of the diaphragm 40, the space 48 being vented to the atmosphere by means of an opening 50. The diaphragm 40 is preferably made of very thin, flexible cloth, as for example, nylon fabric impregnated with a suitable coating material to render the diaphragm impervious, or the diaphragm may be made of synthetic rubber or similar material of a character which is unaffected by contact with hydrocarbon fuels.

In the carburetor of the invention, the fuel is delivered into the region of the choke band 15 or region of maximum restriction of the Venturi 14 to attain maximum aspiration by the high velocity air flow through the Venturi, the fuel being delivered through an outlet or orifice 54 which is in communication with the fuel chamber or reservoir 38 in a manner and through passages hereinafter described.

The charge forming apparatus or carburetor is inclusive of means operatively associated with and adapted to be controlled by the diaphragm 40 for regulating or controlling the flow of fuel from a supply into the shallow fuel chamber or passage 38. The diaphragm control arrangement for a fuel inlet valve means is particularly shown in detail in FIGURE 5. The body 10, at the region defining a wall of the chamber 38, is formed with an elongated recess 56 shaped to accommodate a lever or lever member 58 which is pivotally supported upon a pin 60 mounted in suitable bores formed in the body 10.

It should be noted that the fuel chamber or passage 38 is not vented to the atmosphere and fuel from the chamber is delivered into the mixing passage 12 solely by engine aspiration through the single orifice or fuel outlet 54. By reason of the fact that fuel is delivered into the mixing passage solely by aspiration effect of differential or subatmospheric pressure in the mixing passage acting upon the fuel chamber 38, there is no predetermined or defined static fuel level in the chamber 38 as this may vary by reason of air or gas bubbles in the fuel supply or when the carburetor is tilted.

The diaphragm 40 is preferably reinforced throughout a circular central region thereof by means of a thin metal disk 62 which is secured to the diaphragm by means of a headed member or rivet 64, the head portion 65 thereof being in contact with the longer arm of the lever 58 as shown in FIGURE 5. As fuel is delivered into the mixing passage through the orifice or outlet 54 under the influence of reduced pressure communicated through fuel passages or ducts hereinafter described with the fuel chamber 38, the flow or delivery of fuel into the mixing passage depletes the supply in the passage or chamber 38, further decreasing the pressure in the chamber 38 which flexes the diaphragm effecting movement of the lever member 58.

The body 10 is provided with a boss portion 68 having a threaded opening 70 adapted to accommodate a fitting 72 which is connected by means of a pipe or tube 74 with a fuel tank (not shown) or other supply or source of fuel to be delivered into the chamber 38. The threaded opening 70 is formed with a continuat1on opening 76 which is in communication with a passage 78 as shown in FIGURE 5. Disposed at the terminus of the passage 78 is a valve seat 79 formed of resilient synthetic rubber or similar material, the member 79 being formed with a port 80. An elongated valve or valve member 82 is disposed between the short arm 84 of the lever 58 and the seat region of the resilient valve seat 78.

In the illustrated embodiment, the body portion of the valve member 82 is of triangular cross-section to facilitate flow of fuel along the facets of the triangular cross-section of the valve but the same way be of other cross-sectional configuration, such as a Maltese cross shape. The upper extremity of the valve member 82 adapted for seating against the member is of cone-shaped configuration as shown at 86 to seat against the circular edge region of member 79 defining the port 80. A fitting 88 i threaded into a suitable threaded bore axially aligned with the passage 78 and functions to retain the valve seat 79 in proper position as shown in FIGURE 5. The lower end of the valve member 82 contacts or rests directly upon the short arm 84 of the lever 58. The lever 58 is normally biased toward a position to cause the valve 82 to close the port 80, the bias being in a direction to rotate the lever member 58 in a clockwise direction as viewed in FIGURE 5. An expansive coil spring 90 contained in a bore 92 formed in the body being utilized as the biasing means, one end of the spring 90 being bottomed in the bore 92 and the other end engaging the long arm of the lever 58 at a region proximate to the fulcrum pin 60 as shown in FIGURE 5.

The spring 90 is fashioned to exert the proper pressure upon the valve member 82 to prevent ingress of fuel through the port 80 in the valve member under the fuel pressures normally provided by the gravity head of fuel in the fuel tank which is usually positioned slightly above the carburetor. It is to be understood however that while the carburetor of the invention is particularly adapted for use where the fuel flows to the carburetor by gravity, the fitting 72 may be connected with a suitable fuel pump if desired for supplying fuel under comparatively low pressure.

It should be noted that the valve portion 86 is faced toward the incoming fuel entering through the duct 78 so that the effective hydrostatic pressure against the valve portion 86 is determined by the area of the port 80 in the valve seat 79. Thus by making the port 80 relatively small, a comparatively low pressure is exerted against the valve portion 86. Hence a minor or relatively low differential pressure is effective to move or flex the diaphragm 40 and through the medium of the lever 58 facilitates movement of the valve portion 86 away from the seat 79 to admit fuel through the port 80 into the passage or chamber 38.

The sensitiveness of this mechanism may be varied or regulated by changing the effective pressure of the spring 90 acting against the lever 58. Thus where higher fuel pressures are existent in the inlet duct 76, the spring 90 may be fashioned or dimensioned to exert a greater pressure upon the lever 58 to maintain the valve portion 86 normally in a seated or valve closing position when no aspiration is effective in the chamber 38 to actuate the diaphragm 40.

Through this arrangement the balance of forces effective to maintain the valve 86 in closed position is sufficiently low so that a minute reduction in pressure in the fuel chamber 38 under the influence of the aspiration effect in the mixing passage set up by engine operation brings the fuel orifice 54 into operation to discharge fuel into the Venturi 14 and opens the valve 85 to admit fuel to the chamber 38. It has been found that a differential or reduced pressure in the chamber 38 equal to that required to support a column of Water about three-eighths of an inch in height is sufiicient to initiate fuel delivery through the orifice or outlet 54 into the mixing passage.

In such arrangement it has been found that for most installations a choke valve is not required. However it should be noted in FIGURE 2 that the body is formed with boss portions 92 which may be bored to accommodate a rotatable shaft 93 which supports a choke valve of the disk-type 95, the shaft 93 and the choke valve 95 being shown in broken lines in FIGURE 2. Thus the use of a choke valve is optional depending upon the characteristics of the internal combustion engine or a combustion heater with which the carburetor or charge forming device may be used.

A simple yet effective duct system is provided for conveying or delivering fuel from the chamber or passage 38 to the orifice or outlet 54 into the Venturi 14 of the mix- 6 ing passage. Such arrangement is illustrated in FIG-

URES

3, 4 and 6. A passage or duct 94 is drilled into the body aligned with the fuel discharge orifice 54 as shown in FIGURE 6 and the entrance to passage 94 sealed by a member 96 such as a lead pellet pressed into the entrance region of the duct 94.

A boss portion 98 of the body 10 as shown in FIG- URE 6 is provided with a bore 100 accommodating an adjustable valve body or member 102 which is formed with a tapered or needle valve portion 104 projecting into a duct 106 which is in communication with the duct 94. The valve member 102 is formed with a threaded portion 108 which is threaded into a threaded portion of the bore 100.

A resilient sealing member or O-ring 110 formed of synthetic rubber surrounds a portion 112 of the valve member 102 to prevent leakage of fuel to exterior of the carburetor body 10. A head portion 114 of member 102 extends exteriorly of the boss 98 and is provided with a kerf 115 to accommodate a tool for adjusting the position of the needle portion 104 of valve member 102 to meter, regulate or control fuel flow to the discharge outlet or orifice 54 through the passage or duct 106.

As shown in broken lines in FIGURES 3 and 4, a passage or duct 118 establishes communication between the bore 100 and the recess 56. Thus fuel flows from the chamber or passage 38 through the duct 118 into the bore 100 past the needle valve 104 through duct 106 into the duct or passage 94 and through the outlet or orifice 54 into the choke band or restricted portion 15 of the mixing passage 12 into the engine aspirated air stream flowing through the mixing passage. By adjusting the valve member 104 the rate of fuel flow discharged from the orifice 54 may be accurately controlled.

The carburetor of the present invention is particularly usable with engines which operate at substantially constant speeds or within a defined or governed speed range. By adjusting the throttle 18 the speed of the engine may be controlled within the desired operable range and when the throttle valve 18 is nearly closed, the engine will operate at idle speed through the discharge of fuel through the single orifice 54. Such arrangement is operable as the chamber 38 is unvented to the atmosphere and due to the proximity of the chamber 38 to the mixing passage 12, a low aspiration and hence a very minor pressure differential will initiate and maintain delivery of fuel through the orifice 54.

While the arrangement of the invention is particularly adaptable for comparatively small or fractional horsepower engines, it has been found that the diameters of the various regions of the mixing passage may be varied to render the carburetor usable for various sizes of engines and for combustion heaters. Thus, for example, the most restricted portion or choke band 15 of the Venturi may be as small as three-sixteenths of an inch in diameter and may be increased to about seven-eighths of an inch in diameter dependent upon the engine with which the carburetor is used. Where the choke band area is modified, the diameter of that portion of the mixing passage containing the throttle 18 is also modified to accommodate a reduced or increased flow of mixture dependent upon the size of the engine with which the carburetor is used. Thus by modifying the size of the mixing passage, the carburetor may be readily adapted to different size engines from a single size of carburetor body construction. This permits volume production and hence a substantial reduction in the cost of carburetors of this character.

Through the use of a diaphragm controlled fuel inlet valve, the carburetor may be operated under severe vibrations extreme tilting of its position such as that encountered in chain saws or lawnmowers and under a wide range of fuel inlet pressures. The carburetor of the invention is substantially immune to vibrations and hence it is rendered particularly adaptable for use in lawnmowers.

For most uses it is preferable to admit or bleed air into the fuel just prior to its discharge through the outlet or orifice 54 to provide an emulsion delivered into the mixing passage. An air bleed for performing this function is illustrated in FIGURES 3 and 4 and includes a bore or duct 120 opening into the mixing passage adjacent the entrance end of the Venturi 14 as shown in FIGURE 4. A metering passage or duct 122 connects the bore 120 with the bore or passage 94 and is of comparatively small size to meter or regulate the admission of a small amount of air from the inlet region 16 of the mixing passage through the metering duct 122 for mixing with the fuel in the duct or passage 94 prior to the delivery of the fuel through the outlet orifice or duct 54 into the mixing passage. The amount of air admitted to the fuel in the passage 94 may be varied or metered by modifying the size of the metering passage or duct 122. It is to be understood that the passage 120 does not function as a fuel discharge orifice but functions solely as an air bleed, the same being subjected to a reduced pressure zone of the inlet region of the mixing passage.

Where the carburetor of the invention is utilized for supplying a combustible mixture to combustion heaters such as those employed on trucks during the winter to avoid freezing of perishables, the Venturi arrangement 14 may be dispensed with and mixing passage formed as a cylindrical bore in the body 10. In such installations the air velocities are comparatively low and hence the area of the mixing passage is made comparatively small to attain sufficient aspiration by air flow to effect reduced pressure in the chamber 38 suflicient to effect delivery of fuel into the mixing passage.

FIGURE 7 is illustrative of another form of valve means utilized to regulate or control the flow of fuel into the fuel chamber. In this form a valve member 130 in the form of a sphere or ball is utilized as a valve means for regulating the fuel flow into the chamber 38. In this arrangement the carburetor body is provided with a threaded bore 132 adapted to receive a cage or valve guiding member 134. The valve guiding member is formed with a shoulder which supports a valve seat member 138 of resilient material such as synthetic rubber or resilient material which is not affected by hydrocarbon fuels. The hollow guide 134 is dimensioned to loosely accommodate the valve or ball member 130 in the manner illustrated in FIGURE 7. The fitting 134 is formed with a thin-walled portion 140 engaging a spacer or gasket 142 disposed above the valve seat member 138. The ball member or valve 130 directly contacts the short arm 84' of the lever 58' whereby movements of the lever 58' are transmitted directly to the ball valve 130 to control the fuel flow into the chamber 38'.

The ball member 130 is preferably made of moldable polyamide resin, commercially known as nylon which is of comparatively lightweight and has long wearing qualities so that a reliable means is provided for controlling the ingress of fuel into the chamber 38. Such arrangement as illustrated in FIGURE 7 may be inexpensively manufactured. The valve retaining or guiding cage or fitting 134 may be fashioned of metal or may be molded of polyamide resin or the like.

The carburetor may be provided with a fixed metering means in lieu of the adjustable metering needle valve 104. FIGURE 8 illustrates a portion of the carburetor of the character shown in FIGURE 4 with a fixed metering orifice. In this figure, the carburetor body 10", the Venturi 14", the lever 58", diaphragm 40", chamber 38", closure plate 42" and the fuel outlet passage 54" opening into the Venturi are of the same construction as the corresponding components shown in FIGURE 4. The fuel duct 150 as shown in FIGURE 8 is in communication with the fuel discharge passage 54". Fixed in a recess in the carburetor body at the terminus of the duct 150 is a member or disk 152 which is provided with a passage or 'opening 154 of a size to admit or meter fuel flow into the 8. fuel r'netering'm'eans of this character may be utilized where the charge forming device is used with combustion heaters or with engines operating under substantially constant load and speed conditions.

FIGURES 9 through 11 illustrate a carburetor or charge forming device embodying a modified arrangement for transmitting movements of the diaphragm to the fuel inlet control valve. The carburetor is inclusive of a body or body member 210 formed with a mixing passage 212 which preferably includes a Venturi configuration 214. The mixing passage is fashioned With an air inlet region or air horn 215. A filter (not shown) may be employed at the air inlet region to filter the air admitted through the air inlet.

The inlet 215 of the mixing passage is provided with a disk-type choke valve 216 mounted upon a revoluble shaft 217 journaled in bores in boss portions 218 formed on the body 210, the shaft 217 being provided with an arm 219 for manipulating the choke valve. The mixture outlet region 220 of the mixing passage is provided With a throttle valve of the disk-type 221 mounted upon a shaft 222 journaled in bores formed in the body 210. An operating arm 223 is secured on the shaft 222 exteriorly of the body 210. The arm 223 may be provided with a fitting 228 for manipulating the throttle valve 221, the fitting being adapted for connection with a flexible wire control (not shown).

The carburetor body 210 is fashioned at the mixture outlet end with a mounting flange 231) adapted to be secured to a boss portion 232 formed on the wall of a crankcase of an engine of the two cycle type, or the carburetor may be secured to an intake manifold of an engine of the four cycle type. The mounting flange 230 is secured to the boss 232 by bolts 234.

The carburetor body 210 is formed with a comparatively shallow fuel chamber, passage or reservoir 238. A flexible diaphragm or membrane 240 forms a flexible wall of the shallow chamber 238, an annular gasket 243 being disposed between the peripheral region of the diaphragm and the body 210 to effect a liquid tight seal.

A cover plate 242, formed of sheet metal or molded resinous plastic, disposed beneath the diaphragm 240 is fashioned with a recess providing a space 244 to accommodate flexing movements of the diaphragm, the space 244 being vented to the atmosphere through an opening 245. A peripheral flange 246 of the cover 242, the peripheral region of the diaphragm 240 and the gasket 243 are provided with aligned openings to receive securing screws 248 which extend into threaded openings formed in the body 210 to secure these components in assembled relation.

The diaphragm 240 is preferably made of comparatively thin, flexible cloth, as, for example, nylon fabric coated or impregnated to render it impervious, or the diaphragm may be made of comparatively thin synthetic rubber or similar material of a character which is unaffected by contact with hydrocarbon fuels. The fuel chamber 238 is unvented so that fuel from the chamber is delivered into the mixing passage 212 by engine aspiration effective through fuel delivery orifice means 250 which, in the embodiment illustrated, opens into the restricted region of the Venturi 214.

The cauburetor body 210 is provided with a boss portion 25-2 fashioned with a threaded opening 254 to accommodate a threaded fitting 256 adapted to be connected by a pipe or tube with a fuel tank (not shown) or other supply of liquid fuel. The threaded opening 254 is formed as a continuation of a bore or passage 258 which is in communication with a vertically arranged passage 260, as shown in FIGURE 11. Disposed at the lower end of the passage 260 is an annular valve seat 262 preferably formed of synthetic nub-ber or other suitable material, the annular member providing a fuel inlet port 264.

The body 210 is provided with a passage 266 in which is slidably accommodated an inlet valve body or valve 9 member 268 having a conically-shaped valve portion 270 arranged for cooperation with the valve seat 262 for controlling fuel flow from the supply into the diaphragm fuel chamber 238. The carburetor arrangement embodies a novel means for transmitting movements of the diaphragm 240 to the movable valve member 268.

As particularly shown in FIGURES 10 and 11, the body 210 at a region defining the chamber 238 is fashioned with an elongated recess 272 to accommodate a lever or lever member 274. In this form of the invention, the lever member 274 at a region intermediate its ends is formed with a semi-annular portion 276, the portion being of U- shape or saddle-like vconfiguration and adapted to straddle or fit over a fulcrum pin 280.

As shown in FIGURE 10, the regions of the carburetor body at each side of the recess 272 are fashioned with semi-cylindrically shaped pockets or recesses 282 in which is received the regions of the fulcrum pin 280 at each side of the lever 274.

The body 210 is fashioned with a threaded opening to receive a screw 284, particularly shown in FIGURES 10 and 15, the head 286 of the screw engaging the pin 280 for securing the same in the semi-cylindrically shaped recesses 282. The diaphragm 240 is preferably reinforced by disks 290 and 292 formed of metal or plastic secured to the diaphragm by means of a rivet 294, the head 295 of the rivet being adapted to be engaged with the long arm 275 of the lever 274 as shown in FIGURE 11.

The short arm 298 of the lever 274 is adapted for engagement with the lower extremity of the inlet valve member 268. The body 210 is fashioned with a recess or bore 300 which receives a coil spring 302, the spring engaging the long arm of the lever at a region close to the fulcrum pin 280. The spring 302 serves to normally bias the valve member 268 toward valve closing position. The coil spring 302 is comparatively weak so that aspiration in the mixing passage transmitted through the orifice means 250 will effect upward flexure of the diaphragm against the biasing .pressure of the spring 302 to admit fuel past the valve member 268 into the fuel chamber 238.

The valve body 268 is of polygonally-shaped crosssection to facilitate fuel flow past the valve into the chamber 238. The fuel chamber 238 is unvented and as fuel is delivered into the mixing passage through the orifice mean-s under the influence of aspiration or reduced pressure in the mixing passage, the flow or delivery of fuel into the mixing passage from the chamber 238 further decreases or reduces the pressure in the chamber 238 causing upward fiexure of the diaphragm which is transmitted through the lever 274 to permit the valve member 268 to open and admit fuel from the supply into the fuel chamber 238.

The particular configuration of lever 274 and the method and means of mounting the lever on the fulcrum pin 280 is a low cost construction and one which facilitates rapid assembly of these components in the carburetor. In assembling these components the carburetor is inverted from the position shown in FIGURE 11, the coil spring 302 is placed in the recess 300 and the valve member 268 inserted in the bore 266.

The lever 274 is then inserted in the recess 272 and the fulcrum pin 280 engaged in the semicircular region 276 of the lever and the end regions of the fulcrum pin nested into the recesses or pockets 282. The screw 284 is then inserted and drawn up to the position shown in FIGURE whereby the head 286 fixedly secures the fulcrum pin 280 in place. The lever 274 may be inexpensively manufactured as it merely requires a bending operation to form the saddle-shaped configuration 276 in the lever.

FIGURES 12 through 14 illustrate a modified arrangement of connection or contact between the lever, the inlet valve body and member carried by the diaphragm. The lever 274' is fulcrumed by means of a pin 280 in the manner hereinbefore described. The short arm 298' is bifurcated providing a recess 304. The inlet valve member 268 has a tenon portion 306 formed with a peripheral or diabolo shaped recess 308 which engages in the recess 304 formed by the furcations 305 to provide a shackle connection. In the arrangement illustrated in FIGURE 12, the movements of the lever 274' in both directions effect movement of the valve member 268' providing for effective positive control of the portion of the valve member 268'.

FIGURES 13 and 14 illustrate an arrangement of establishing a shackle or positive connection between the diaphragm and the motion transmitting lever whereby movements of the diaphragm are positively transmitted to the lever. The head of the rivet 294' is provided with a tenon 310 fashioned with a diabolo shaped recess 312. The long arm of the lever 274 is bifurcated at its end providing a recess 3114, the furcations 316 of the lever fitting in the recess 3-14 in the manner shown in FIGURES 13 and 14.

Through the arrangement shown in FIGURES 12 through 14, flexure of the diaphragm 240' in either direction is positively transmitted through the lever 274 to the valve member 268. Through this arrangement the valve member 268' will not stick in the valve seat as it is under the positive control of movements of the lever and the diaphragm.

FIGURES 16 and 17 illustrate a modified form of inlet valve and combined valve seat and valve guide unit for controlling flow of liquid fuel into the fuel chamber. With particular reference to FIGURE 16, the carburetor body 210a is fashioned with a shallow fuel chamber 2381:, one wall of which is provided by the flexible diaphragm 240a, the diaphragm being enclosed and held in position by means of a cover plate 24 2a of the character shown in FIGURE 11. The lever 27411 is of the same character as shown in FIGURE 11, being formed with a saddle portion 276a straddling a fulcrum pin 280a.

The diaphragm is provided with a headed rivet 294a, the head of which engages the long arm of the lever. The lever is biased toward valve closing position by means of a biasing spring 302a. Fashioned in the carburetor body 210a in alignment with the fuel inlet passage 260a is a counterbore or enlarged circular recess 320 in which is snugly fitted a combined inlet valve seat and valve guide unit 322. In this form of the invention, the inlet valve comprises a spherically-shaped member or ball 324 which may be of metal or plastic such as nylon or Delrin (polyoxymethylene) or other suitable material.

The unit 322 comprises a cylindrically-shaped body 325, the exterior surface of which is snugly fitted in the circular recess 320. The member 325 is formed with a countenbore 326 which terminates in a ledge or shoulder 3 28 providing a valve seat for the ball valve 324.

The counterbore 326 provides a skirt portion 330 which extends downwardly preferably at a region below the center of the ball valve 324, the wall of the counterbore 326 forming a guide to prevent dislodgment of the ball valve 324 but providing sufiicient clearance for the ball valve to seat properly.

The ball valve is engaged by the short arm 298a of the lever 274a in the manner shown in FIGURES 16 and 17. The combined valve seat and valve guide unit 322 is preferably made of synthetic rubber or other resinous plastic or material which is not affected by contact with hydrocarbon fuels.

The arrangement shown in FIGURE 18 illustrates a modified form of combined valve seat and valve guide unit for the inlet valve means. In this form of construction, the combined valve seat and guide unit 340 is of cylindrical shape and, at its upper exterior region, is fashioned with an integral outwardly extending circular ridge or head 342. The carburetor body is fashioned with a counterbore 34 4 and a recess 346 to accommodate the circular ridge 342 formed on the member 340.

The member 3 40 is provided with a coun-terbore 348 1 1 forming a ledge or valve seat 3 50 engaged by the ball shaped valve 3-52. The ball is engaged by the short arm 298b of the diaphragm actuated lever.

The member 340 is made of semi-hard synthetic rubber or suitable plastic which is yieldable to facilitate insertion of the member 340 into the counterbore 344 to engage the ridge 342 in the recess 34-6 to securely maintain the member 340 in the bore 344. In the construction shown in FIGURE 18, the unit or member 340 will not be dislodged by reason of substantial fuel pressure in the passage 2601) such as may be supplied by a fuel P p- It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than as herein disclosed, and th present disclosure is illustrative merely, the invention comprehending all variations thereof.

Having thus described this invention, I claim:

1. Charge forming apparatus, including, in combination:

(a) a body member formed with a mixing passage;

(b) a fuel chamber formed in the body below the mixing passage;

(c) a flexible diaphragm and having a central upstanding member;

(d) fuel delivery orifice means opening into the mixing passage;

(e) passage means connecting the orifice means with the fuel chamber;

(f) a fuel inlet duct formed in the body adapted to receive liquid fuel from a source of supply;

(g) an elongated movable inlet valve member disposed within said duct and having an upper tip which cooperates with said fuel delivery orifice and also has a shouldered lower end portion;

( h) said lower end portion of said movable inlet valve member extending downwardly into said fuel chamber and disposed a substantial distance away from said central upstanding member on said diaphragm;

(i) a fulcrum pin in said fuel chamber above said diaphragm which has a circular section adjacent said lower end of said movable inlet valve member;

(j) a lever member in said fuel chamber extending over said fulcrum pin and extending between and engaging said upstanding diaphragm member and said lower end of said movable inlet valve member;

(k) said lever member having an intermediate "semicircular up-standing section straddling the top portion of said circular section of said fulcrum pin in pivotable relation;

(1) the length of said lever between said fulcrum pin and said movable inlet valve member being directly connected to one end of said semi-circular section and extending radially outward therefrom;

(m) the other end of said semi-circular section having a planar tangentially extending portion;

(11) the length of said lever between said fulcrum pin and said central upstanding member being connected to the other end of said tangentially extending portion;

() a spring which engages the top surface of said lever immediately adjacent the fulcrum pin on the portion thereof which engages said upstanding m-ovable member, so that the lever is held in engagement with said fulcrum pin; and

(p) the end of said lever adjacent said shouldered end portion of said inlet valve member having a forked configuration which engages said shouldered portion.

2. Charge forming apparatus as set. forth in claim 1,

wherein: Y

(a) a shackle connection is provided between the other end of said lever and said central up-standing member of the diaphragm.

3. Change forming apparatus, including, in combination:

(a) a body member formed with a mixing passage;

(b) a fuel chamber formed in the body below the mixing passage;

(c) a flexible diaphragm and having a central upstanding member;

(d) fuel delivery orifice means opening into the mixing passage;

(e) passage means connecting the orifice means with the fuel chamber;

(1g) an inlet valve guide of non-metallic material disposed in the lower end of said fuel duct which has a stepped bore therein with the enlarged portion at the lowermost end of said guide;

(h) a spherical ball shaped movable inlet valve member of larger diameter than the smaller portion of said bore and which fits into said enlarged portion of said bore;

(i) a fulcrum pin in said fuel chamber above said diaphragm which has a circular section adjacent said movable inlet valve member;

(j) a lever member in said fuel chamber extending over said fulcrum pin and extending between and engaging said up-standing diaphragm member and said movable inlet valve member;

(k) said lever member having an intermediate semicircular up-standing section straddling the top portion of said circular section of said fulcrum pin in pivotable relation;

(n) the length of said lever between said fulcrum pin and said central upstanding member being connected to the other end of said tangentially extending portion; and

(o) a spring which engages the top surface of .said lever immediately adjacent the fulcrum pin on the portion thereof which engages said upstanding member so that the lever is held in engagement with said fulcrum pin.

References Cited by the Examiner UNITED STATES PATENTS 1,626,581 4/1927 Gaunt et al. 137505.47 2,311,827 2/ 1943 Hansen. 2,724,584 11/1955 Armstrong. 2,775,981 1/1957 Zonker. 2,796,838 6/ 1957 Phillips. 2,855,127 10/1958 Lerner et al. 137-53311 X 2,916,042 12/1959 Brady 137533.15 X 2,984,465 5/ 1961 Hazzard. 2,987,303 6/1961 Jones. 3,151,627 10/1964 Rice. 3,160,681 12/ 1964 Johnson. 3,160,684 12/1964 Carlson et al. 3,201,096 8/1965 Barr.

HARRY B. THORNTON, Primary Examiner.

RONALD R. WEAVER, Examiner.

Claims

1. CHARGE FORMING APPARATUS, INCLUDING, IN COMBINATION: (A) A BODY MEMBER FORMED WITH A MIXING PASSAGE; (B) A FULE CHAMBER FORMED IN THE BODY BELOW THE MIXING PASSAGE; (C) A FLEXIBLE DIAPHRAGM AND HAVING A CENTRAL UPSTANDING MEMBER; (D) FUEL DELIVERY ORIFICE MEANS OPENING INTO THE MIXING PASSAGE; (E) PASSAGE MEANS CONNECTING THE ORIFICE MEANS WITH THE FUEL CHAMBER; (F) A FUEL INLET DUCT FORMED IN THE BODY ADAPTED TO RECEIVE LIQUID FUEL FROM A SOURCE OF SUPPLY; (G) AN ELONGATED MOVABLE INLET VALVE MEMBER DISPOSED WITHIN SAID DUCT AND HAVING AN UPPER TIP WHICH COOPERATES WITH SAID FUEL DELIVERY ORIFICE AND ALSO HAS A SHOULDERED LOWER END PORTION; (H) SAID LOWER END PORTION OF SAID MOVABLE INLET VALVE MEMBER EXTENDING DOWNWARDLY INTO SAID FUEL CHAMBER AND DISPOSED A SUBSTANTIAL DISTANCE AWAY FROM SAID CENTRAL UPSTANDING MEMBER ON SAID DIAPHRAGM (I) A FULCRUM PIN IN SAID FUEL CHAMBER ABOVE SAID DIAPHRAGM WHICH HAS A CIRCULAR SECTION ADJACENT SAID LOWER END OF SAID MOVABLE INLET VALVE MEMBER; (J) A LEVER MEMBER IN SAID FUEL CHAMBER EXTENDING OVER SAID FULCRUM PIN AND EXTENDING BETWEEN AND ENGAGING SAID UPSTANDING DIAPHRAGM MEMBER AND SAID LOWER END OF SAID MOVABLE INLET VALVE MEMBER; (K) SAID LEVER MEMBER HAVING AN INTERMEDIATE SEMICIRCULAR UP-STANDING SECTION STRADDLING THE TOP PORTION OF SAID CIRCULAR SECTION OF SAID FULCRUM PIN IN PIVOTABLE RELATION;