US2205457A - Carburetor - Google Patents

Description

June 25, 1940. F. o. BALL-Er AL 2,205,457

CARBURETOR Filed March 15, 1937 2 Sheets-Sheet 1 RED/ERICK 0. BALL AND F THOMAS BALL.

June 25, 1940. Q BALL ET AL 2,205,457

' GARBURETOR Filed March 15, 1957 2 Sheets-Sheet 2 3mm FREDERICK 0.-5/1LL. AND THOMAS M. B/ILL.

Patented June 25, 1940 CARBURETOR Frederick 0. Ball and Thomas M. Ball, Detroit, Mich.; Cornelia M. Ball, executrix of Frederick 0. Ball, deceased, assignors to Ball and Ball Carburetor Company, a copartnership composed of Cornelia M. Ball and Thomas M. Ball Application March 15, 1937, Serial No. 130,841

1 Claim.

This invention relates to improvements in carburetors.

More particularly, the invention pertains to improved carburetor pick-up pump systems of the type by which the discharge of fuel from a carburetor of a vehicle engine is temporarily augmented during opening movements of the throttle valve thereof.

The fuel displacing elements of pick-up pump systems of this character are generally actuated by, and in relation to, operation of accelerator mechanism by which the throttle valve of the carburetor is controlled.

The effort required to displace the temporarily augmenting fuel charge increases the pedal pressure required to operate the accelerator mechanism and to open the throttle valve. This pressure requirement is preferably held at a low value so as to guard against tiring of the foot of the operator of the vehicle.

Since the discharge from the pick-up system of a vehicle engine carburetor is desired only during throttle valve opening movements, precaution must be taken to obstruct flow or pull-over of fuel from the pick-up system discharge orifice under the action of the normal carburetor suction applied thereon. The interposing of valve mechanism for this purpose between the pump and the discharge outlet of systems of this kind, which has to be moved to open position against its weight or other closing force, and against the suction thereon to permit the discharge of fuel, imposes further pressure requirements on the accelerator mechanism.

One of the main objects of this invention is the provision of improved fuel displacing mechanism and fuel pull-over discharge preventing means which together enable the accelerator pedal pressure requirements to be held within substantially low limits.

Another object of the invention is to provide an improved light weight valve for the outlet passage of a pick-up pump system of this kind which is normally held in closed position, partly by the carburetor vacuum which is relieved when the valve is initially partly opened and which therefore does not impose excessive pedal pressure requirements upon the accelerator system.

Further objects of the invention are to provide means for relieving the discharge outlet of a 5 duces the amount of valve weight, or otherwise member thereof through its fuel displacing stroke; to provide means of this character which are energized during closing movement of the throttle valve of a carburetor and the corresponding movements of the accelerator mechanism associated therewith; and to provide a pull-over preventing valve of the foregoing character which requires so little opening force that an excessive pedal pressure is not necessary in order to accommodate the use of a return spring in the accelerator system that is capable of satisfactorily loading the fuel displacing mechanism during the throttle closing operations.

Additional objects of the invention are the provision of a pick-up accelerator pump system, of which the quantity discharge of fuel therefrom per unit of throttle opening and. the initial fuel discharging pressure can be independently adjustably predetermined to meet the different requirements of diverse seasonal'and territorial conditions; and to provide a system of this character by which the initial discharge.

pressure can be increased or held substantially unchanged, as desired, while the quantity of discharge per unit of throttle movement through a portion of its range of movement is unchanged and while holding the total pump discharge at a selected value.

' Other objects of the invention are the provision of resilient means for moving the fuel displacing member at different rates during movement thereof through successive portions of its fuel discharging stroke in order to vary the timed rate of discharge of selected portions of the temporarily fuel augmenting charge; to provide resilient means of this character which exerts a maximum fuel displacing action during the initial range of opening movement of the throttle valve of a carburetor and which gradually decreases the fuel displacing force thereafter; and to provide a helical spring for this purpose having coil portions which vary successively in pitch through selected parts of its length.

Still further objects of the invention are to provide pick-up pump actuatingmechanism of improved construction; to provide mechanism of this kind which includes detachably connected parts comprising inexpensive sheet metal stampings; and to provide an improved stamped sheet metal rod and detachable operable lever therefor which are separable when disposed in one relative position and which are normally yieldably held against movements into such position by the resilient means that imparts the actuating force of such lever to the fuel displacing element of the pump and structure.

Illustrative embodiments of the invention are shown in the accompanying drawings, in which:'

Fig. l is a side elevational view, partly insection, of a carburetor embodying the invention and showing portions thereof removed to disclose the underlying structure.

Fig. 2 is a vertical sectional view taken on the line 22 of Fig. 1. r

Fig. 3 is a central vertical sectional view taken on the line 33 of Fig. 1.

Fig. 4 is a fragmentary plan view of pick-up pump actuating mechanism taken on the line 4-4 of Fig. 2.

Fig. 5 is a fragmentary elevational view, partly in section, showing the parts of the pump actuating structure illustrated in Fig. 4, in the position to which they are moved during assembly and disassembly of the pump actuating structure.

Fig. 6 is a horizontal sectional view taken on the line 6-6 of Fig. 5.

In the form of the invention illustrated in Figs. 1 to 6, inclusive, of the drawings, the improved pick-up pump system is shown as embodied in a carburetor, generally designated by the numeral l0, having a body portion comprising die cast wall structure. Formed in the wall structure of the body portion H is a cylinder L2 in which a piston I3 is reciprocably mounted. A piston rod i4 is attached at its lower end to the piston Hi. The piston rod I4 is of rectangular cross section, as illustrated in Figs. 4 to 6, and it is provided with a head portion i5 which is slightly longer than the width of the main length of the piston red. A spiral spring i6 having successively adjacent turns, preferably of varying pitch, bears between the piston l3 and a shoulder formed in the wall portion of the carburetor. The spring I6 normally urges the piston downwardly, as viewed in Fig. 2, toward the discharge end of its fuel displacing structure.

Provided in the body portion H of the carburetor is pump actuating mechanism comprising a vertically shiftable rod i8 which is slidably mounted in a slot l9 formed in the wall structure of the carburetor, as illustrated in Fig. 2. A substantially horizontal plate portion 23 formed on the upper end of the rod 8 extends laterally therefrom into registration with the upper end portion of the piston rod E4. The plate portion 2|],illustrated in Figs. 4 to 6, inclusive, is provided with a pair of intersecting slots 23 and 24. The slot 23 is slightly longer than the length of the head i5 of the piston rod I4 and will therefore accommodate passage of the head and piston rod therethrough. The slot 24 is slightly longer than the width of the rod l4 but shorter prevents withdrawal of the piston rod l4 from Formed intermediate. the ends of the slot 24. the rod l4 are a pair of opposite slots 25, between which is provided a reduced section 26 that is small enough in width to, accommodate turning of the piston rod l4 relative to the plate portion 20 when the reduced section 26, is disposed at the intersecting parts of the slots 23 and 24.

With this structure, the actuating lever l8 and piston rod |4 may be detachably connected together by inserting the head portion |5 of the piston rod |4 through the long slot 23 of the plate 20 and moving the plate into registration with the reduced section 26 of the piston rod. Thereafter the piston rod may be turned through substantially 90 relative to the plate 20 in order to bring the width of the piston rod into registration with the smaller slot 24 which is just long enough to accommodate the width of the piston rod. The spring l6 yieldably holds the head |5 of the piston rod in contact with the upper surface of the plate 20 and prevents unintended movement of the plate into registration with the reduced section 26 and slots 25 of the piston rod.

The carburetor ID has a fuel mixture passage 21 provided with an upper inlet end 28 and a discharge end 29 which registers with a fuel mixture passage section 30 formed in a throttle body 3| which is detachably connected to the lower end of the carburetor body H by bolts 32. For all purposes of description of this invention, the throttle body and a carburetor may be considered as being integral or permanently connected together. A throttle valve 33 mounted on a valve stem 34 which is journaled in the wall of the throttle body 3|, serves to control the flow of fuel mixture from the carburetor. The valve stem 34 has an external end portion on which is mounted a bell crank lever 35. A link 36 operatively connects the lower end portion of the pump actuating member |8 to one arm of the bell crank lever 35 and a tension spring 31 attached to the other end of the lever 35 and anchored on a lug 38 of the throttle body normally tends to close the throttle valve 33 and to' urge the lever i8, piston rod l4, and piston |3 to their uppermost positions against the action of the spring Hi. When the throttle valve 33 is opened, the plate 26 is moved downwardly, thereby permitting the spring to urge the piston l3 throughout its fuel displacing stroke.

Fuel is admitted into the interior of the cylinder l2 during upward movement of the piston 3 through a valve controlled port 39 which is supplied with liquid fuel from the interior of a fuel reservoir 4|], as illustrated in Fig. l. Formed in the wall structure of the carburetor body portion H is a fuel passage 4| which communicates at one end with the interior of the cylinder |2 through a port 42. The other end of the fuel passage 4| has an outlet opening 43 which communicates with the fuel mixture passage 27 at a region thereof of relatively high carburetor suction. In the carburetor illustrated in the drawings, a venturi 44 is provided in the fuel mixture passage 27 and the outlet 43 is located substantially at the maximum restriction of this venturi. The liquid fuel passage 4| is restricted by a threaded plug 45 located adjacent the outlet opening 43 of this passage. The threaded plug 45 is provided with a tubular discharge nozzle 46 which is located in registration with the outlet opening 43 of the passage 4| and which is adapted to discharge liquid fuel therethrough under the pressure created by the piston I3.

Formed in the body portion H of the carburetor adjacent the fuel passage 4| is a valve chamber 41 in which a valve 48 is slidably mounted. The valve 48 has a conical end por tion fitted in the outlet orifice 42 of the cylinder |2 which, when in closed position, is adapted to prevent withdrawal of liquid fuel from the cylinder I2 by the carburetor suction applied on the outlet opening 43. The valve 48 has a weighted upper end portion 49 by which its conical end is urged into closed position. The amount of weight or otherwise derived valve closing force required is dependent upon the degree of suction to which the liquid fuel passage 4| is subjected andin order to maintain the weight of the valve within suitably low limits so as to prevent the requirement of the application of excessive pressure by the spring I6 and correspondingly excessive throttle valve closing and opening force requirements, provision is made for relieving some of the carburetor suction in the discharge end portion of the liquid fuel passage II.

This is accomplished by the provision of a vent passageway leading from a region of lower carburetor suction within the fuel mixture passage 21 and communicating with the liquid fuel passage M at a location between the restriction 46 of this passage and the outlet opening 43 thereof. By virtue of this construction, the degree of suction tending to withdraw liquid fuel from the pick-up pump system when thelatter is not in operation, is materially reduced and the force required to maintain the valve 48 closed against this suction is accordingly reduced. As a result, the spring I6 does not have to be constructed to exert sufiicient force to unseat a heavy valve and therefore the throttle closing spring 3'! which energizes the spring I6 may be of correspondingly lower strength. It follows that the pedal pressure requirements of the accelerator mechanism (not shown) by which the throttle valve 33 is operated, may be held within suitably low limits. This is accomplished while still being able to obtain the benefit of the discharging of the temporarily augmenting fuel charge into the region of the fuel mixture passage of subs'tantially maximum suction.

Operation of the piston I3 by a preloaded spiral spring assures a relatively large temporarily augmenting fuel discharge during the initial stages of the fuel displacing stroke of the piston'while the throttle valve 33 is opened from its closed position. Subsequent movement of the piston I3 is eifected by the spring I6 after the latter has expanded to such a state that the rate of fuel discharge is decreased in order to prevent overloading of the carburetor with fuel. As the spring I6 expands from a substantially fully compressed position to a fully expanded state, the fuel displacing force thereof gradually decreases from a maximum to a minimum.

The quantity of fuel discharged per unit of throttle movement throughout its initial range of opening movement may be adjustably predetermined by selectively attaching the link to the bell crank lever 35 at any of the holes I00 therein so as to predetermine the effective radius through which the crank lever operates upon the link 35. Selective placement of the lower end of the link 35 in the holes I00 produces such variation in the extent to which the spring I6 is compressed when the throttle is'in its closed position as to cause the initial fuel displacing pressure exerted by the piston I3 to increase as the quantity of the discharge per unit of throttle movement is increased. This is a desirable action in many instances for usually when more fuel is required during initial throttle valve opening movements, a faster delivery of fuel is also beneficial, particularly under cold weather operating conditions.

The effective radius of the bell crank lever 35 may be varied to change the quantity discharge of fuel per unit of throttle valve opening movement without altering the initial fuel displacing pressure by selectively attaching the lower end of the link 36 to the lever 35 at any one of a series of holes IOI located substantially on an arc described about the center of the opening I02 in which the upper end of the link 36 is received. The adjustment of the connection between the lever 35 and the link 36 does not vary the state of compression to which the spring I6 is subjected when the throttle valve is closed and therefore does not change the initial fuel discharging pressure created by the spring.

These adjustments of the quantity of initial fuel discharge produce a corresponding change in the total pump discharge by varying the length of the stroke of the piston. This variation may be compensated for and the total pump discharge produced by complete opening of the throttle valve may be predetermined by selectively positioning a pin I03 in one of a series of openings I04 formed in an extension I05 of the head I5 of the piston rod I4. The extension I05 passes through an opening in the top wall structure of the carburetor and the pin I03 is adapted to engage the external surface of the latter to limit the extent of downward movement of the piston I6.

Although but several specific embodiments of the invention are herein shown and described, it will be understood that various changes in the size, shape and arrangement of parts may be made without departing from the spirit of my invention.

What we claim is:

A pump including a cylinder, a piston reciprocable in said cylinder, a piston rod of rectangular cross section attached to said piston and having a head of greater length than the width of the main length of said rod and having a reduced neck portion intermediate its length, an operating element comprising a plate having intersecting slots therein, one of said slots being shorter than the length of said head and the other slot being longer than said head, said neck portion accommodating turning of said rod relative to said plate portion when said neck is disposed in the intersecting parts of said slots to bring said head into registration with said short slot, and a spring bearing between said piston and said cylinder normally holding said plate portion against registering with the neck portion of said rod. Y

FREDERICK 0. BALL. THOMAS M. BALL.

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