US3275305A

US3275305A - Fuel feed and charge forming apparatus with priming device

Info

Publication number: US3275305A
Application number: US452826A
Authority: US
Inventors: Warren D Nutten
Original assignee: Tillotson Manufacturing Co
Current assignee: Tillotson Manufacturing Co
Priority date: 1965-05-03
Filing date: 1965-05-03
Publication date: 1966-09-27
Anticipated expiration: 1983-09-27

Description

p 27, 1966 w. D. NUTTEN 3,275,305

FUEL FEED AND CHARGE FORMING APPARATUS WITH PRIMING DEVICE 5 Sheets-Sheet 1 Filed May 5, 1965 m M \Mik Ml w? h .n

INVENTOR. M/P/QEA/ D. A/L/TTEA/ JW C3. 6W

flrromvey Sept. 2?, H66 w. D. NUTTEN 3,275,305

FUEL FEED AND CHARGE FORMING APPARATUS WITH PRIMING DEVICE Filed May 5, 1965 5 Sheets-Sheet 2 Fig-E Z10 200 74 my) 205 5 Z02 1.15)? mf M zzfll JTTQA A/EV p '7 1 w. D. NUTTEN 3,275,305

FUEL FEED AND CHARGE FORMING APPARATUS WITH PRIM ING DEVICE Filed May 5, 1965 5 Sheets-Sheet 5 INVENTOR. l VAR/P'A/ 0. A/z/TTEA/ Arrow/5 y United States Patent F FUEL FEED AND CHARGE FORMING APPA- RATUS WITH PRIMING DEVICE Warren I). Nutten, Erie, Mich, assignor to The Tillotson Manufacturing Company, Toledo, Ohio, a corporation of Ohio Filed May 3, 1965, Ser. No. 452,826

5 Claims. (Cl. 261-64) This invention relates to fuel feed and charge forming apparatus for delivering fuel and air mixture to an internal combustion engine and more especially to an apparatus of this character embodying a priming device for manually injecting liquid fuel into a fuel and air mixing passage to facilitate starting an internal combustion engine with which the fuel feed and charge forming apparatus is used.

Charge forming apparatus of a character embodying a diaphragm responsive to aspiration in a mixing passage for controlling delivery of fuel into the mixing passage has heretofore been provided with a socalled choke valve to reduce air flow to the mixing passage in order to enrich the mixture for engine starting operations. A conventional choke valve comprises a disc valve in the air inlet region of the carburetor mixing passage mounted on a rotatable shaft provided with a manipulating arm for manually moving the choke valve to substantially closed position during starting operations.

By temporarily closing the air inlet, the engine aspiration is effective during manual cranking of the engine to effect the delivery of fuel to enrich the mixture for engine starting purposes. An arrangement of this type of choke valve mechanism has been employed with diaphragm type carburetors wherein, during engine cranking operations and particularly engines of the two cycle type, the aspiration or reduced pressure created by manual cranking of the engine acts upon the diaphragm to eventually effect delivery of fuel into the mixing passage in sufficient quantity to provide a rich mixture for starting the engine. In the use of two cycle engines, such as those used for powering chain saws, lawn mowers, outboard motors for marine use and the like, it usually requires many cranking revolutions of the engine by manual means, particularly under cold weather conditions, to effect a starting of the engine. This difficulty is particularly present in the starting of chain saw engines, employing diaphragm type carburetors, particularly in cold temperatures, as power saws of this character are conventionally used in felling trees in Winter weather. As chain saw engines are portable, such engines embody a manual means for rotating the engine to effect starting, and the starting means have to be operated many times in cold weather to start the engine.

The present invention embraces a charge forming apparatus of the diaphragm type embodying a method of and means for establishing pressure in a fuel chamber in the charge forming apparatus to inject or deliver liquid fuel under pressure into the fuel and air mixing passage in advance of cranking the engine in order to promote easy starting of the engine with a minimum of effort upon the part of the operator.

Another object of the invention resides in a diaphragm carburetor embodying a priming means actuable by the operator and requiring little effort for positively injecting fuel from a fuel chamber into the mixing passage of the carburetor without the use of other mechanism and eliminating the conventional choke valve and its operating means.

Another object of the invention is the provision of a priming device embodied in a diaphragm type carburetor or charge forming apparatus which may be manipulated by the operator with comparatively little effort to effect 3,275,305 Patented Sept. 27, 1966 delivery of fuel for engine starting purposes into the mixing passage whether the carburetor fuel chamber is initially dry or whether it is necessary to effect the elevation of fuel from a fuel tank into the carburetor fuel chamber thence into the mixing passage and independent of cranking operations of the engine.

Another object of the invention resides in a fuel feed and charge forming apparatus embodying a priming means for manually and positively delivering liquid fuel into the mixing passage of the charge forming apparatus under pressure to positively provide an enriched fuel mixture for the engine and thereby enable easier starting of the engine.

Another object of the invention resides in a combined diaphragm type carburetor and priming device wherein a variable volume pressure chamber is employed to develop pressure in a fuel chamber in the carburetor to eject fuel under pressure into the mixing passage and wherein the fuel inlet valve of the carburetor functions to facilitate the establishment of pressure in the fuel chamber in providing for pressure injection of fuel into the mixing passage for engine starting purposes.

Another object of the invention resides in a priming device for a diaphragm type carburetor in which an operator actuated component maybe positioned adjacent the carburetor or remote therefrom Without impairing the utility or effectiveness of the priming device.

Another object of the invention resides in a priming device for a diaphragm carburetor having an unvented fuel chamber wherein the inlet valve for controlling fuel flow from a supply into the fuel chamber of the carburetor and valve means to prevent bleeding of air into the fuel delivery system assures the establishment of pressure in the fuel chamber by manipulation of the priming device by the operator for positively injecting fuel into the mixing passage preparatory to starting the engine.

Another object of the invention resides in the provision of a diaphragm carburetor of a priming device actuated by the operator for manually creating pumping pulsations or differential pressures in the fuel chamber of the carburetor effective to cause fuel flow from a supply to enter the diaphragm fuel chamber of the carburetor and eject such fuel under pressure into the mixing passage to provide :an enriched mixture for engine operation.

Further objects and advantages are within the scope of this invention such :as relate to the arrangement, op-' eration and function of the related elements of the structure, to various details of construction and to combinations or 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 top plan view of a fuel feed and charge forming apparatus or carburetor embodying one form of priming device of the invention;

FIGURE 2 is a side elevational view of the fuel feed and charge forming apparatus shown in FIGURE 1;

FIGURE 3 is a bottom plan view of the construction shown in FIGURES 1 and 2 with certain portions broken away;

FIGURE 4 is an elevational view of the air inlet end of the construction shown in FIGURE 1;

FIGURE 5 is an elevational view of the mixture outlet end of the construction shown in FIGURE 1;

FIGURE 6 is a vertical longitudinal sectional view taken substantially on the line 6-6 of FIGURE 5;

FIGURE 7 is a transverse sectional view taken substantially on the line 7-7 of FIGURE 3;

FIGURE 8 is a detail sectional view taken substantially on the line 8-8 of FIGURE 2;

FIGURE 9 is a detail sectional view taken substantially on the line 99 of FIGURE 1;

FIGURE 10 is a fragmentary detail sectional view taken substantially on the line 1010 of FIGURE 1;

' FIGURE 11 is a fragmentary detail sectional view taken substantially on the line 11-11 of FIGURE 1;

FIGURE 12 is a fragmentary detail sectional view taken substantially on the line 1212 of FIGURE 8;

FIGURE 13 is a sectional view similar to FIGURE 6 illustrating a form of priming means associated therewith;

FIGURE 14 is a sectional view illustrating a modified form of priming device;

FIGURE 15 is a sectional view illustrating another modification of priming device of the invention;

FIGURE 16 is a bottom plan view of the charge forming apparatus or carburetor construction illustrating another form of priming device embodied therein, and

FIGURE 17 is a fragmentary sectional view similar to FIGURE 12 illustrating a check valve means associated with the secondary fuel delivery system.

While the priming device is illustrated as embodied in a fuel feeding apparatus and diaphragm carburetor of compact construction particularly usable for supplying combustible mixture to a chain saw engine of the two cycle type, it is to be understood that the priming device may be embodied in other forms of diaphragm carburetor which function generally in the same manner as the carburetor and fuel feed device disclosed herein.

Referring to the drawings in detail and initially to the form of the invention shown in FIGURES 1 through 13, the charge forming apparatus or carburetor component of the construction includes a body or body member 10 of cast metal or other suitable material fashioned with an air and fuel mixing passage 12 having an air inlet region 14, a Ven-turi 16 providing a restricted regionor choke band 18 and a mixture outlet 20, as particularly shown in FIGURE 6.

The mixture outlet end of the carburetor has a uniplanar surface 22 which is adapted to mate with a boss portion 23 formed on the crankcase 24 of an engine of the two cycle type, or to mate with the entrance of a mixture inlet manifold of an engine of the four cycle type. The mixture outlet 20 registers with an opening in the boss portion 23 of the crankcase where the engine is of the .two cycle type for delivering combustible mixture into the engine crankcase through a conventional reed valve construction (not shown) at the mixture admission opening.

The air inlet end 14 of the carburetor may be equipped with an air filter or air cleaner (not shown) of conventional construction. The carburetor body 10 is provided with two cylindrical bores or passage 26 extending entirely through the body and accommodating bolts (not shown) for securing the air filter to the carburetor body and securing the body to the engine crankcase, the bolts being threaded into suitable threaded bores (not shown) provided in the engine crankcase boss 23.

Extending across the mixture outlet region 20 and iournaled in bores in the body 10 is a shaft 32 supporting a. disc-type valve 34 providing a throttle valve for regu- [ating or controlling flow of fuel and air mixture to the :ngine. As shown in FIGURE 5, the axis of the throttle valve shaft 32 is disposed at an angle A with respect to a iorizontal axis BB. A plane through the axes of the lrilled passages or bores 26 is at an angle D with respect the horizontal axis BB and in crossing relation with :he axis of the shaft 32 so that the mounting bolts re- :eived in the bores 26 do not interfere with the fuel pas- :ages and channels formed in the carburetor body or nterfere with the throttle shaft 32.

A portion of the throttle shaft 32 exteriorly of the body l0 is equipped with an arm 40 for manipulating the hrottle. If desired, a cable (not shown) may be conlected with one of a series of openings 41 in the arm 40 or manipulating the throttle from a remote position.

A coil spring 44 is positioned between the body 10 and the arm 49, one end being anchored to the body and the other end engaging the arm to normally bias the throttle valve toward near closed or engine idling position. An abutment screw 48 is threaded into an opening in a lug 49 on the body 10 for adjusting the engine idling position of the throttle valve.

As particularly shown in FIGURES 6 and 7, the body 10 is formed with a generally circular shallow chamber or recess 52 providing a fuel chamber in the body. A flexible member, diaphragm or membrane 54 extends across the recess and forms a flexible wall of the fuel chamber 52, a gasket 56 being disposed between the pe ripheral region of the diaphragm and the portion of the body defining the chamber 52 to form a liquid tight seal. A cover member 58 has a depressed central region providing a space or air chamber 60 to accommodate flexing movement of the diaphragm.

A plurality of screws 62 extend through registering openings formed in the cover member 58, the diaphragm 54 and the gasket 56 are threaded into suitable bores formed in the body 10 to secure these components in assembled relation. The cover member 58 has an opening 64 to vent the space or dry chamber 60 to the atmosphere.

The diaphragm 54 is arranged to be actuated or flexed by aspiration or reduced pressure established in the mixing passage 12 for controlling or metering the flow or delivery of liquid fuel into the diaphragm fuel chamber 52, the fuel chamber 52 being unvented.

The body 10 is provided with a fuel inlet duct 68 in communication with a fuel delivery passage of a fuel feed or pumping means hereinafter described, the duct 68 opening into an enlarged bore 70 accommodating a fuel filter or screen 72, shown in FIGURE 7. Pressed or snugly fitted into the inlet duct 68 .is .a tubular member or sleeve 74 providing an inlet port 76. The body is formed with a bore or passage in which is slidably disposed an elongated valve body or valve member 82 of polygonal- 1y shaped cross section to facilitate flow of liquid fuel into the fuel chamber 52.

The valve body is formed with a conically-shaped valve portion 86 adapted to cooperate with the port 76 in the sleeve 74 for metering fuel into the fuel chamber 52. If desired, the member 74 may be made of nonmetallic material such as synthetic rubber or other suitable material. A motion multiplying means, such as a lever 96, is fulcrumed intermediate its ends on a fulcrum pin 98 for communicating flexure or movement of the diaphragm 54 to the valve member 82 to control the position of the inlet valve 86 for regulating fuel flow into the chamber 52 in accordance with the degree of aspiration or reduced pressure established in the fuel chamber 52 from the mixing passage 12.

As shown in FIGURE 7, a member 90 has a portion extending through a central opening in the diaphragm and through reinforcing

discs

92 and 93 disposed at opposite faces of the diaphragm, and a portion of the member 90 swaged to secure these components in assembled relation.-

As shown in FIGURE 3, the head of a screw 100, threaded into a bore in the body, secures the fulcrum pin within the fuel chamber 52.

The long arm of the lever has a bifurcated or forked end engaging in a recess formed on the member 90, the recess being defined by a head portion 106 on the member 90, this arrangement establishing a positive articulate connection between the diaphragm 54 and the lever 96. The short arm of the lever 96 has its extremity bifurcated or forked to straddle a tenon 114 formed on the lower end of the inlet valve body 82 and terminating in a head portion 116.

Through the connection provided between the member'- sponsive to the flexing movements of the diaphragm 54 in either direction of flexing movement of the diaphragm. An expansive coil spring 118 has one end nested in a socket 119 formed in the body 10, the spring, engaging the long arm of the lever adjacent the fulcrum, exerts a comparatively small force urging the inlet valve 86 toward closed position to normally interrupt fuel flow through the inlet port 74.

Aspiration established in the mixing passage 12 is communicated through fuel passages to the chamber 52, the reduced pressure or aspiration elevating the diaphragm 54 to swing the lever 96 in a counterclockwise direction as viewed in FIGURE 7 to open the inlet valve 86 to valve in fuel into the fuel chamber 52.

The carburetor includes a main or primary fuel delivery system for delivering fuel into the mixing passage for normal and high speed engine operation, and a secondary fuel delivery system for engine idling and low speed operation. The main fuel delivery system embraces a main orifice construction which includes a cylindrically shaped fitting 120 pressed or snugly fitted into a bore in the body 10, the fitting having an outlet region 122 providing a main fuel delivery orifice.

The fitting 120 is provided with a counter bore 124 in which is disposed a ball valve or check valve member 126 which, when the carburetor is in horizontal position as shown in FIGURE 7, seats against the ledge formed by a second counter bore or passage 128, the ball check 126 being retained in the counter bore 124 by a grid-like retainer 130 in the orifice or outlet region 122. The fitting 120 has a peripheral recess 132 which is in communication with the counter bore 128 by transverse passages 134.

As shown in FIGURE 7, the body is provided with a threaded bore 136 accommodating a threaded portion of a high speed adjusting valve member 140. The valve body is formed with a needle valve portion 142 which cooperates with a restricted passage 144 in communication with the recess 132 in the fitting 1-20. The valve body 140 is fashioned with a knurled manipulating head 146. A coil spring 148 is disposed between the body and the head 146 to establish sufiicient friction to hold the valve member 140 in adjusted position. The bore 136 receives fuel from the chamber 52 through a duct 150, shown in FIGURE 7.

The secondary fuel delivery system for engine idling and engine low speed operation is illustrated in FIG-

URES

6, 8 and 12. The body is fashioned with a small supplemental chamber 154 which is in communication with a mixing passage by an engine idling orifice 156 and a low speed orifice 158. As shown in FIG- U-RE 12, the carburetor body is fashioned with a bore 160 having a threaded portion accommodating the threaded body of a valve member 164, the latter having a needle valve portion 166 cooperating with a restricted passage 168 opening into the supplemental chamber 154.

The valve member 164 is provided with a knurled manipulating head 170, a coil spring 172 between the head 170 and the body providing friction for retaining the valve member in manually adjusted position.

The needle valve portion 166 cooperates with the restriction 168 to meter or regulate fuel flow into the supplemental chamber 154 for delivery through one or both of the

secondary orifices

156 and 158. Fuel is delivered into the bore 160 from the fuel chamber 52 through a passage or duct 176 shown in FIGURE 12.

Fuel delivery through the main orifice or delivery system takes place as follows with reference to FIGURE 7: Fuel from the chamber 52 flows through the duct 150 into the bore 136 past the needle valve 142 through the restricted passage 144, the peripheral recess 132, transverse passages 134, counter bore 128 past the ball check valve 126 and through the opening 122 into the mixing passage 12 for mixing with air moving through the passage. The main orifice 122 opens into the choke band 18 of the Venturi 16.

When the throttle valve 34 is in engine idling or low speed position fuel flow takes place as follows with reference to FIGURES 6 and 12: Fuel from the chamber 52 flows through the duct 176 into the bore 160 past the needle valve 166 through the restriction 168 and into the supplemental chamber 154 for delivery through either or both of. the

orifices

156 and 158.

The normal function of the check ball or valve means 126 in the main orifice construction is to prevent back bleeding of air through the main orifice into the secondary fuel channel system when one or both of the secondary orifices are delivering fuel into the mixing passage. Other- Wise, air bled into the secondary fuel system through the main orifice would lean the idling fuel mixture to an extent causing the engine to stall.

The arrangement includes a fuel feeding means or fuel pump construction for supplying fuel under com paratively low pressure to the inlet duct 68 of the carburetor. The pumping means includes a flexible impervious diaphragm 200 disposed at the opposite side of the carburetor body from the fuel metering or control diaphragm 54, the pumping diaphragm 200 engaging an upper planar surface region of the body 10, as particularly shown in FIGURES 6 and 7. A sealing gasket 204 is disposed between a cover plate 202 and the pump diaphragm 200.

The plate 202, gasket 204- and the diaphragm 200 have registering openings accommodating securing bolts 206 threaded into bores in the body 10 to secure these components in assembled relation. The body 10 has a concave recess providing a fuel compartment 208, the diaphragm 200 extending across the recess. The plate 202 is fashioned with a recess providing a pulse or pumping chamber 2 10, the diaphragm 200 providing a flexible wall between the fuel compartment 208 and the pulsing or pumping chamber 2110.

The diaphragm 200 is fashioned with an integral flap valve 212 which controls fuel flow from a supply through an inlet port 214, shown in FIGURE 9, the cover 202 having a recess 2 16 to accommodate opening movement of the flap valve 212. The recess 216 is in communication with the fuel compartment 208 through connecting

ducts

218 and 219, shown in FIGURE 9.

The body 10 is provided with a hollow nipple 222 receiving one end of a flexible tube 224 providing a fuel line connected with a fuel tank or other fuel supply (not shown). Fuel flowing through the hollow nipple 2'22 enters a small supplemental compartment 226 in communication with the fuel inlet port 214.

The plate 202 is formed with a recess 228, a portion 230 of the pumping diaphragm forming a common wall between the supplemental chamber 226 and the recess 228. The recess 228 may be vented to the atmosphere by a vent opening 231. The supplemental chamber 226 forms a surge chamber or variable volume region, the diaphragm portion 230 forming a yielding medium for absorbing the surge pulses of the moving liquid fuel under the influence of the rapid opening and closing movements of the inlet flap valve under the pumping action of the pumping diaphragm.

The pumping diaphragm 200 is provided with a second integral flap valve portion 234 cooperating with an outlet port 236 in communication with the pump fuel compartment 208 by a passage 238. A recess 240 in the cover plate 202 accommodates opening movements of the outlet flap valve 234 and forms a fuel passage to the carburetor fuel inlet duct 68, as shown in FIGURE 10. A filter or screen 244 is disposed in a bore in the body 10 between the recess 240 and the inlet duct 68 for filtering the incoming fuel.

The pumping diaphragm is arranged to be actuated by varying fluid pressures occurring in the engine crankcase of the two cycle engine during engine operation. The duct arrangement for connecting the pulse chamber 210 with the source of varying fluid pressure is shown in FIG- URE 11. A pulse passage or channel 259 formed in the body 10 has its entrance in the end of the carburetor body secured to the crankcase of the engine, the channel 250 being arranged to register with an opening 251 in the crankcase wall, shown in broken lines in FIGURE 1.

The channel 250 is in communication with the pumping chamber 210 through interconnecting

channels

252, 253 and 254, which with the channel form a pulse passage to transmit pressure pulsations or varying fluid pressures in the engine crankcase to the pumping compartment 210.

The varying pressures in the pumping chamber 210 cause rapid flexure or vibration of the region of the diaphragm 200 defining the flexible wall of the recess 210 to set up a fuel pumping action in the fuel chamber 208. Through the varying fuel pressures developed in the fuel chamber 208 by pulsations of the diaphragm 200, in cooperation with the inlet and

outlet fiap valves

212 and 234, fuel from a supply enters the small chamber 226 from the hollow nipple 222 thence flows through the inlet 214 past the flap valve 212 through connecting

ducts

218 and 219 through the fuel chamber 208, through interconnecting ducts and past the outlet flap valve 234 to the region of the inlet duct 68 in the carburetor.

The flow of fuel through the inlet duct 68 into the fuel chamber 52 in the carburetor is regulated or controlled by the relative position of the metering diaphragm 54 Which is influenced or actuated by reduced pressure in the mixing passage 12 for delivery into the mixing passage through the primary or secondary fuel delivery systems hereinbefore described. The surge chamber 226 provides for a more continuous and smooth flow of fuel through the fuel chamber 208 of the pumping means, the pumping diaphragm 200 being vibrated at high frequencies during engine operation by varying pressure at each revolution of the engine. 7

The carburetor and fuel pumping means of the charcter disclosed herein is usually employed with two cycle engines of the type used for powering chain saws, lawn mowers and the like and it is conventional practice to initiate starting of such engines by a manual means, rotating the engine several times until sufiicient aspiration is developed to deliver fuel into the mixing pass-age from the chamber 52. Heretofore it has been conventional practice, in order to temporarily develop high aspiration in the mixing passage and provide an enriched fuel mixture for starting, to utilize a choke valve to substantially close the air inlet and thereby increase the aspiration in the fuel delivery orifice means.

With a conventional choke valve arrangement it is usual that several manual rotations of the engine are required before an enriched ignitable mixture is delivered to the engine especially under low temperature conditions. The present invention embodies a mannually actuable means for temporarily establishing increased pressure in the fuel chamber 52 to effect the positive injection from the fuel chamber of fuel under pressure into the mixing passage preparatory to starting the engine and without restricting the air inlet of the carburetor by a choke means.

FIGURE 13 illustrates one form of manually actuable variable volume means for establishing increased pressure in the fuel chamber 52 of the carburetor. The air inlet end of the body 10 adjacent the fuel chamber 52 is provided with a threaded bore 260 adapted to receive a hollow nipple 262, the hollow interior of the nipple being in communication with the fuel chamber 52 through a connecting duct 264.

Mounted upon a panel or other suitable support means 266 is a squeeze bulb molded or formed of synthetic rubber of a character which is not subject to deterioration by contact with hydrocarbon fuels, or fashioned of molded plastic having similar characteristics. The thickness of the wall of the squeeze bulb is suflicient to main- 8 tain the bulb 268m its normal expanded condition as shown in FIGURE 13 but sufficiently thin to enable the operator to distort or collapse the bulb 268 by squeeze pressure or by finger pressure applied to the bulb.

In the embodiment illustrated in FIGURE 13 the squeeze bulb construction may be molded with a recess to be received in a slot in a support means or panel 266 to provide adequate support for the squeeze bulb. The squeeze bulb construction is molded with an integral tubular portion or tube 274 connected with the nipple 262 on the carburetor.

The foregoing described arrangement provides a priming means for positively injecting fuel under pressure into the mixing passage preparatory to starting the engine. When the engine is not in operation, the fuel inlet valve 86 in the carburetor, shown in FIGURE 7, is held in closed position under the pressure of the expansive coil spring 118. If the engine has been in use, fuel is contained in the fuel chamber 52. When the operator desires to start the engine, the throttle valve 34 is opened and the operator collapses the squeeze bulb or bulbous element 268, either by squeezing pressure or by forwardly exerted pressure against the semispherical region of the bulb.

This action injects air pressure from the squeeze bulb into the fuel in the chamber 52. The inlet valve 86 is closed and, as the fuel chamber is unvented, the increase in pressure on the fuel in the chamber ejects the fuel from either the primary or the secondary orifices or both into the mixing passage. The operator may collapse the squeeze bulb several times prior to starting the engine depending upon the ambient temperature conditions. If the temperatures are low, then repeated collapsing of the squeeze bulb may be required to deliver suflicient fuel to provide an enriched mixture for engine starting.

When the operator has completed the step of injecting fuel under pressure into the mixing passage, the engine is started in the usual manner. When pressure on the squeeze bulb is removed, the bulb returns to its normal expanded condition, a conventional characteristic of squeeze bulb construction, setting up a reduced pressure in the fuel chamber 52 which causes the diaphragm 54 to be elevated, as viewed in FIGURE 7.

This movement of the diaphragm moves the lever 96 in a counterclockwise direction, compressing the spring 118, and opening the inlet valve 86 to effect flow of fuel into the chamber 52. Upon subsequent collapsing of the squeeze bulb 268, the fuel inlet valve 86 is closed by the spring 118 and pressure developed in the fuel chamber 52 positively ejects fuel into the mixing passage. The fuel is replaced by fuel flow through the inlet port from the supply during expanding movement of the squeeze bulb 268 to its normal position.

By this method, the mixing passage is provided with fuel to form an enriched mixture suitable for starting the engine prior to cranking operation of the engine. After several priming operations, any air in the squeeze bulb 268 is gradually replaced with fuel from the fuel chamber and thereafter the collapsing of the squeeze bulb 268 by manual pressure acts on liquid fuel only to effect ejection of liquid fuel into the mixing passage.

The ball check valve 126, shown in FIGURE 7, performs an important function during manipulation of the squeeze bulb 268. During return movement of the collapsed squeeze bulb to its normal expanded condition, the check 'ball 126 closes the main orifice passage 128 to prevent back bleeding of air from the mixing passage into the fuel chamber so that reduced pressure is established in the fuel chamber to cause the diaphragm 54 to open the inlet valve 86 to valve in fuel.

Ordinarily it is found that the

secondary orifices

156 and 158 are of such small size that back bleeding of air through these orifices does not appreciably afiect the pressures developed by the operation of the squeeze bulb 268. Another force of air impeding media is present which tends to prevent back bleeding of air through the secondary orifices during operation of the squeeze bulb. The needle valve 166 extending into the restriction 168, shown in FIGURE 12, provides a very thin annular space around the needle valve. The liquid fuel in this annular space tends to form a capillary seal by capillary action, such method and arrangement being of a character described and claimed in Phillips Patent 2,841,372.

Another form of squeeze bulb or primer construction is shown in FIGURE 14. In this form a fitting 280 has a shank portion 282 extending through an opening in a support means or panel 284, the shank means 282 being threaded to accommodate a securing nut 286 which is drawn up in the position shown in FIGURE 14 to secure the fitting to the panel or support means 284.

The shank portion 282 is integral with a nipple or spud portion 288, the latter receiving the end region of a flexible tube 290 adapted to be connected to the nipple 262 on the carburetor, shown in FIGURES 6 and 13.

The fitting 280 is provided with a circular portion 292 fashioned with a circular groove 294. A flexible squeeze bulb or hollow bulbous element 296 of generally semispherical shape has a terminus region or circular bead 298 engaging in the circular recess 294. A metal snap ring 300 of conventional construction embraces the terminal region 298 of the squeeze bulb or bulbous element 296 to effect an air tight connection or seal between the squeeze bulb 296 and the portion 292 of the fitting 280. The fitting is provided with a central passage 302 estab lishing communication between the interior of the squeeze bulb 296 and the flexible tube 290.

The bulbous element or squeeze bulb 296 is of molded flexible synthetic rubber or plastic which has sutficient elastic characteristics, as is conventional with squeeze bulb constructions, to return to its normal expanded position shown in FIGURE 14 after it has been collapsed or squeezed by the operator to inject fuel from the fuel chamber 52. into the mixing passage 12 preparatory to starting the engine in order to provide an enriched mixture in the mixing passage 12 of the carburetor.

FIGURE 15 illustrates a modified form of bulbous element or squeeze bulb construction. In this form a fitting 306 is fashioned with a hollow shank portion 308 projecting through an opening in a support means or panel 310, a portion of the shank being threaded to accommodate the securing nut 312 for holding the fitting in assembled relation with the panel 310. The fitting has a nipple portion 314 adapted to receive the end of a flexible tube 316 adapted to be connected with the nipple 262 shown in FIGURES 6 and 13.

An enlarged circular portion 318 of the fitting 306 is fashioned with a circular groove or recess 320, the recess being of generally dove-tail shape in cross section. In this form, the bulbous element 322 of a semispherical hollow shape and of synthetic rubber or suitable flexible plastic is molded with a terminal portion 324 filling the dovetail shaped groove 320, thus securing the bulbous element or squeeze bulb 322 permanently to the fitting 306. The operation of the squeeze bulb or bulbous element 322 is the same as in forms of the invention shown in FIGURES 13 and 14.

FIGURE 16 illustrates another form of primer construction of the invention. In this form the carburetor body 10a is integrally formed with a laterally extending cylindrically shaped boss portion 330 fashioned with a circular cylindrical bore 332 extending partially through the boss 330. Slidably fitted in the cylindrical bore 332 is aplunger or member 334 which may be of semi-hard synthetic rubber or molded plastic or other suitable material resistant to deterioration by hydrocarbon fuels.

The plunger or piston 334 may be provided with a peripheral recess accommodating an O-ring 336 engaging the interior wall of the bore to effect a seal between the plunger and the wall of the cylinder.

Disposed within the cylinder 332 is an expansive coil spring 338, one end of which is bottomed or seated in a counter bore 340, the other end engaging the plunger 334 to bias the plunger to the normal retracted position shown in FIGURE 16. The cylindrical bore 332 is in communication with a fuel chamber 52, shown in FIGURE 13, by a passage or duct 342. A rod 344 is secured to the plunger 334, the rod extending through an opening in a panel or support means 346, the distal end of the rod being provided with a manipulating button 348 to enable the operator to reciprocate the plunger 334 in the cylinder 332.

A washer 350 surrounds the rod at a region spaced from the panel 346 and is secured to the rod. A comparatively weak expansive coil spring 354 is disposed between the abutment or washer 350 and a grommet 356 mounted in an opening in a panel 346, the spring 354 serving to resiliently position the plunger 334 normally at one end of the cylinder 332 in the position shown in FIGURE 16.

In the operation of the construction shown in FIGURE 16, the operator, preparatory to starting the engine, reciprocates the rod 344 through the medium of the grip member or finger button 348 one or more times to extrude or project liquid fuel under pressure from the chamber 52 into the mixing passage on each inward or pressure stroke of .the plunger 334 and, upon return stroke of the plunger under the expansive pressure of the spring 338, fuel is valved in to the fuel chamber '52 past the inlet valve 86, shown in FIGURE 7, under the influence of reduced pressure temporarily developed in the fuel chamber by retraction of the plunger 334.

'In the several forms of primer construction illustrated in FIGUR ES 1 and 13 through 16, a variable volume chamber or hollow element is provided wherein the volume is varied by manual operation of an operator to positively eject or deliver liquid fuel from the fuel chamber 52 into the mixing passage for engine starting purposes.

In most installations or uses of the carburetor, the secondary orifices 1:56 and 158 are of very small size, for example a number seventy drill, being a diameter of 28 thousandths of an inch, or orifices of smaller size may be employed for delivering fuel into the mixing passage for engine idling and low speed operation.

Where secondary orifices of larger diameters are desired for engine idling and low speed operation augmenting the tendency for air to feed back through the orifices into the fuel chamber 52 during operation of the priming means, a check valve member may be utilized in the secondary fuel delivery system to prevent any back bleeding.

FIGURE 17 illustrates a valve construction of this character. FIGURE 17 is similar to FIGURE 12 and illustrates the supplemental chamber 154", an idling orifice 15 a manually operable valve 164" having a needle valve portion 166" cooperating with a restricted passage 360 for regulating or metering fuel flow to the secondary orifices. A bore 160" containing the valve member 164 is in communication with the fuel chamber 52 by a fuel .passage 176". The restricted passage 360 opens into a small counter bore 362 in which is disposed a ball valve or check ball 366 of a size suflioient to close the restricted passage 360. Disposed at the entrance of the counter bore 362 containing the ball valve 366 is a perforated member or screen 368 to maintain the ball valve 366 in the counter bore 362. Thus, in installations where the capillary seal, provided by the fuel between the needle valve 166 and the wall of the passage 360, may be ineffective to prevent back bleeding of air into the fuel chamber 52 upon the expansion of the bulbous element shown in FIGURES 13, 14 and 15 or upon retraction of the plunger 334, the ball valve 366 is caused by such reduced pressure to close the end of the restricted passage 360 to prevent air back bleeding through the passage 176" into the fuel chanber 52.

In this manner reduced pressure is developed upon expansion of the squeeze bulb or upon retraction of the priming element effective to open the inlet valve 85 and valve in fuel into the chamber 52, and fuel projected into the mixing passage by pressure exerted on the bulbous priming element or inward movement of the plunger 364 in the form shown in FIGURE 16.

One of the advantages in utilizing a flexible bulbous element such as the element shown in FIGURES 1'3, 14 and 15 is that the element may be positioned close to the carburetor or remotely therefrom as may be expedient without impairing the priming operation.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than as herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

I claim:

1. In combination, a carburetor having a mixing passage and an unvented fuel chamber, a throttle valve in the mixing passage, a flexible diaphragm forming a wall of the fuel chamber, a fuel inlet in the carburetor, an inlet valve for the inlet, motion transmitting means disposed between the inlet valve and the diaphragm whereby movement of the diaphragm controls the inlet valve to regulate flow of liquid fuel from a supply into the fuel chamber, passage means in communication with the fuel chamber for delivering fuel into the mixing passage, means including an auxiliary fuel storage member in communication With the fuel chamber manually actuable by an operator for forcing auxiliary fuel into the fuel chamber to eject fuel in the fuel chamber into the mixing passage through said passage means, and means in said :passage means to impede air flow from the mixing passage into the fuel chamber so that reduced pressure is established in said fuel chamber and said diaphragm is caused to open said fuel inlet valve.

2. In combination, a carburetor having a mixing pas: sage and an unvented fuel chamber, a throttle valve in the mixing pass-age, a flexible diaphragm forming a wall of the fuel chamber, a fuel inlet in the carburetor, an inlet valve for the inlet, motion transmitting means disposed between the inlet valve and the diaphragm whereby movement of the diaphragm controls the inlet valve to regulate flow of liquid fuel from a supply into the fuel chamber, pass-age means in communication with the fuel chamber for delivering fuel into the mixing passage, an auxiliary fuel storage squeeze bulb in communication with the fuel chamber manually actuable by an operator for forcing auxiliary fuel into the fuel chamber to eject fuel in the fuel chamber into the mixing passage through said passage means, and check valve means in said passage means to impede air flow from the mixing passage into the fuel chamber so that reduced pressure is established in said fuel chamber and said diaphragm is caused to open said fuel inlet valve.

3. A fuel feed system including a carburetor for use with an internal combustion engine, said carburetor having a body provided with a mixing passage and a recess, a throttle valve in the mixing passage, a flexible diaphragm extending across the recess forming therewith an unvented fuel chamber, fuel passage means for conveying fuel from the chamber into the mixing passage, a fuel inlet in the body adapted to receive liquid fuel from a supply, a valve for said inlet, means actuated by the diaphragm influencing the relative position of the inlet valve to control fuel flow into the fuel chamber, variable volume means including an auxiliary fuel storage member in communication with the fuel chamber, said variable volume means being manipulated by an operator to force the auxiliary fuel into the fuel chamber to eject fuel in the fuel chamber through said fuel passage means into the mixing passage, and check valve means in said fuel passage means to impede back bleeding of air into the fuel chamber that reduced pressure is established in said fuel chamber and said diaphragm is caused to even said fuel inlet valve.

4. Apparatus of the character disclosed, in combination, a carburetor having a body member, a mixing passage in the body member, a throttle valve in the mixing passage, .a recess in the body member, a flexible impervious diaphragm extending across the recess and forming therewith an unvented fuel chamber, a fuel inlet in the body member arranged to receive liquid fuel from a supply, a valve for said inlet, primary and secondary fuel delivery orifices opening into the mixing passage, means communicating movement of the diaphragm to the inlet valve to regulate fuel flow from the fuel chamber, fuel passage means in said body member for conveying fuel from the fuel chamber to the primary and secondary fuel delivery orifices, a pulse passage in said body member opening into the fuel chamber, an auxiliary fuel storage member connected to said pulse passage including manually operable pressure pulse establishing means for producing pressure pulses of fuel in the fuel chamber to eject fuel in the fuel chamber into the mixing passage for engine priming purposes, check valve means in said fuel passage means to impede air flow from the mixing passage into the fuel chamber so that reduced pressure is established in said fuel chamber and said diaphragm is caused to open said fuel inlet valve.

5. Apparatus of the character disclosed, in combination, a carburetor having a body member, a mixing passage in the body member, a throttle valve in the mixing passage, a recess in the body member, a flexible impervious diaphragm extending across the recess and forming therewith an unvented fuel chamber, a fuel inlet in the body member arranged to receive liquid fuel from a supply, a valve for said inlet, primary and secondary fuel delivery orifices opening into the mixing passage, means communicating movement of the diaphragm to the inlet valve to regulate fuel flow into the fuel chamber, fuel passage means in said body member for conveying fuel from the fuel chamber to the primary and secondary fuel delivery orifices, tubular means in communication with the fuel chamber, auxiliary fuel storage means associated with the tubular means actuable by the operator for successively forcing auxiliary fuel in the fuel chamber to eject successive increments of fuel in the chamber through the orifices into the mixing passage for engine priming purposes, check valve means in said fuel passage means, to impede air flow from the mixing passage into the fuel chamber so that reduced pressure is established in said fuel chamber and said diaphragm is caused to open said inlet valve, and means associated with said auxiliary fuel storage means including a piston and cylinder.

References Cited by the Examiner UNITED STATES PATENTS 1,166,084 12/1915 Ryder.

. 2,844,102 7/1958 Oishei 103148 2,956,737 10/1960 'I-Iager 230169 3,085,791 4/ 1963 Phillips.

3,141,048 7/ 1964 Schneider.

HARRY B. THORNTON, Primary Examiner.

RONALD R. WEAVER, Examiner.

Claims

1. IN COMBINATION, A CARBURETOR HAVING A MIXING PASSAGE AND AN UNVENTED FUEL CHAMBER, A THROTTLE VALVE IN THE MIXING PASSAGE, A FLEXIBLE DIAPHRAGM FORMING A WALL OF THE FUEL CHAMBER, A FUEL INLET IN THE CARBURETOR, AN INLET VALVE FOR THE INLET, MOTION TRANSMITTING MEANS DISPOSED BETWEEN THE INLET VALVE AND THE DIAPHRAGM WHEREBY MOVEMENT OF THE DIAPHRAGM CONTROLS THE INLET VALVE TO REGULATE FLOW OF LIQUID FUEL FROM A SUPPLY INTO THE FUEL CHAMBER, PASSAGE MEANS IN COMMUNICATING WITH THE FUEL CHAMBER FOR DELIVERING FUEL INTO THE MIXING PASSAGE, MEANS INCLUDING AN AUXILIARY FUEL STORAGE MEMBER IN COMMUNICATION WITH THE FUEL CHAMBER MANUALLY ACTUABLE BY AN OPERATOR FOR FORCING AUXILIARY FUEL INTO THE FUEL CHAMBER TO EJECT FUEL IN THE FUEL CHAMBER INTO THE MIXING PASSAGE THROUGH SAID PASSAGE MEANS, AND MEANS IN SAID PASSAGE MEANS TO IMPEDE AIR FLOW FROM THE MIXING PASSAGE INTO THE FUEL CHAMBER SO THAT REDUCED PRESSURE IS ESTABLISHED IN SAID FUEL CHAMBER AND SAID DIAPHRAGM IS CAUSED TO OPEN SAID FUEL INLET VALVE.