US2562202A

US2562202A - Carburetor arrangement

Info

Publication number: US2562202A
Application number: US632089A
Authority: US
Inventors: Alfred B Metsger
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-07-01
Filing date: 1945-11-30
Publication date: 1951-07-31
Anticipated expiration: 1968-07-31

Description

July 31, 1951 A. B. METSGER CARBURETOR ARRANGEMENT 2 Sheets-Sheet l Original Filed July 1, 1943 l 1 .Mer

l ALFRED B, METSGER- @1 @L July 3l, i951 A. B. METSGER 2,562.9202

` CARBURETOR ARRANGEMENT Original Filed July l, 1943 2 Sheets-Sheet 2 FIG.5

ALFRED la. MET SGER Patented July 31, 1951 UNITED STATES ATENT OFFICE Original application July 1, 1943, Serial No.

493,139. Divided and this application November 30, 1945, Serial No. 632,089

(Cl. 13S-46) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O-. G. 757) Claims.

lThe present invention is intended to permit variation of airow through a carburetor for a given metering suction, for density and compressibility compensation, and for other purposes; and is a division of my application Serial Number 493,139, led July 1, 1943 which has matured into Patent No. 2,396,279 issued March 12, 1946.

In accomplishing the above purposes in the present device the following means and or Afea tures are combined to form the complete carburetor arrangement of the present invention.

Some of these means just mentioned comprise a series of devices to accomplish the result as follows:

In order to permit Venturi area control with low control forces, a servo operated Venturi plate is used;

For giving a mechanical indication of the density of a gas, especially air, a device called a density calculator is used;

A means which gives a mechanical indication of the ratio of two gas pressures is used in this present invention, and same is designated a pressure ratio calculator;

For producing an angular motion equal to that of an angular input, but with much greater torque, and deriving operating power from suction and surrounding gas pressure, a suction servo torque multiplier is used;

In order to automatically connect an air or gas suction line with the greater of two sources of suction, a suction selector valve is used; and

A device is provided herein which is used for controlling the amount of fuel admitted to the carburetor which is dependent upon the pressures found in the throat and other parts of the air or gas inlet.

The above features and devices are combined in the present carburetor arrangement to produce a device of singular utility, the features of which Will be more fully explained as the description proceeds herein.

In the drawings forming a part of the present specification:

Fig. 1 is a diagrammatic cross-sectional elevation of the present invention showing substantially all the above named parts of same.

Fig. 2 is a longitudinal detail section taken on line 2-2 of Fig. 1, of a controlled vent and cap used in connection with the Venturi plate of the invention.

Fig. 3 is a vertical cross-section on line 3-3 of Fig. 5, which last is a suction torque multiplier forming part of this invention.

y Fig. 4 is a vertical section on line 4--4 of Fig. 5.

^ carburetor inlet passage to an engine.

Fig. 5 is a vertical longitudinal section through the above mentioned suction servo torque multiplier, used with this invention.

The variable areav Venturi meter In the drawings is provided a variable area Venturi meter which permits variation of airilow for a given metering suction, for density and compressibility compensation and other purposes in which numeral I indicates the body of an air The numeral 2 represents a Venturi spoon which is pivotally mounted on a pintle 3 and is in the nature of a flat metal plate, having an inclined portion 4 and a curved portion 5 thereon, and which slidably engages in a recess or pocket 6 formed in the body portion of the air vinlet casing 'I as clearly shown in Fig. 1 of the drawings.

It Will be noted that leakage of air is provided against by means of sealing or packing strips 8 on the end 9 of the Venturi spoon 2 Where it engages against the upper face of the recess 6 mentioned. The form of the air inlet casing l' is "shaped at I0, II, and I2, to accommodate the various parts necessary in the construction of the device.

The casing 'I has mounted thereon a closed container I3 shaped as shown in Fig. 1 for the purpose of housing various parts of the invention described herein. The Venturi spoon has a Venturi shape as shown and forms one side of a Venturi passage of preferably rectangular crosssection, and as above stated is pivoted and movable about the pintle 3 so that when the said plate is moved back and forth by means of the servo finger I4, the throat portion I5 of the air inlet I6, can be enlarged or diminished automatically or manually as will be described below.

Numeral II indicates a static throat pressure take-off located in the region of minimum crosssectional area of the Venturi meter. Impat tube I8 is arranged to obtain the total inlet pressure in the passage I6 and is used for accurate determination of the air pressure admitted to the carburetor at I6 as will be fully described herein. A fixed vent 20 in the wall of the Venturi spoon is positioned in the expanding section of the venturi, at such a point that the eiective force or pressure behind the spoon 2 will overcome by a slight margin the effective force on the working face of said spoon.

Numeral 2I indicates a controlled ventV which appears in enlargedi'detail in Fig. 2 of the drawings and is positioned in the wall of the Venturi spoon 2 and has a proper size and location relative to the fixed vent 20 so that it overcomes the effect of the latter and causes motion of the spoon resulting in an increase of Venturi size at the throat I thereof when the vent 2| is partially or completely open. A vent control cap 22 is positioned on the servo finger I4 near the control vent 2| as shown in Fig. 2 detail for the purpose of Varying the eifective area of the-control vent 2| by varying the amount of closure of the orifices 24.

In the enlarged detail of the parts 2|, 22, and I4 shown in Fig. 2 of the drawings it will be seen that the cylindrically shaped part 22, which is fastened to the finger I4 moves axially with respect to part 2| varying the effective area of openings 2d, for the purpose of varying the pressure drop through these openings.

It will be noted that the servo linger I4 is preferably pivoted on the same axis 3- as the Venturi spoon 2 and may be controlled manually or automatically witha reciprocatory movement through the seal I I formed in the wall 25 of the casing 1. The seal I reduces leakage through the said wall 25 around the servo finger Id. The numeral 26 indicates a fixed cam support preferably mounted on the bottom wall 2l of the closed container |3. At point 28 on the support 26 is pivotally mounted a cam 29 which is pivotally connected at 30 with a connecting rod 3|. The cam 29 has an arced slot 3m therein in which the arm extension 32 of the servo finger Iii engages by means of the pintle 33. It is evident that the servo linger I4 and the control vent 2| can be operated by means of the connecting'rod 3|, and the actuation of 3| by means of the apparatus shown in the closed container I3 will be fully described below.

In connection with the variable area Venturi meter just described air to be metered to 'the engine enters the carburetor by passage 34 and through the air inlet I6, and ismetered as usualr in a venturi, except that the area of this Vventuri may be varied vmanually or` automatically as described herein. The pressure on the outer sidey of the Venturi spoon 2 is varied along the direction of airiiow or downward' as shown in Fig. 1 of thedrawings. The fixed vent 29' is placed at a point in the passage 34 where the fluid pressure' has recovered to an intermediate pressure value. l

until the vent' control cap 22 closes the vent 2|A to Such an extent that the Venturivspoon is in equilibrium. The Venturi plate 2a then; follows the motion of the vent control cap 22 which last is'controlled by the servo finger I4, the latter being operated manually or automatically as desired.

The above completes the description of the variable area venturi and the'operati'on of the Venturi'plate 2a used in connection therewith.

The density calculator" One of the means used in operatingrthe connecting rod 3| above mentioned comprises whatA Control vent' 2| if fully' open' is called a density calculater which is used to give a mechanical indication of the density of the fluid used in the present device especially the air portion thereof. A ratio arm 35 having a slot therein is mounted on a revolvable but fixed pivot or pintle Si within the closed oontainer i3 as shown. A slide 38 is adapted to reciprocate in the slot 36 of the ratio arm. A temperature indicator 39 which in this case is a bimetal coil positions the slide 38 a distance from the pivot point 3l' proportional to the inlet temperature obtained by the inlet 40 from the air inlet It as shown. The pressure bellows Lil has an operating rod l2 which connects it pivotally with the slide 38 in the ratio arm 35 as shown.

Thebellows 4I as it reciprocates according to air pressure gives motion to the rod 42 as is at once seen, and to the ratio arm 35 proportional to the inlet pressure through part Ml, in a line of about with the direction of ratio arm 35. The pressure bellows lll, it will be seen, is'pivotally mounted at i3 'in the'support M Acarried-on the inner face of the wall l.

The angular position'of the ratio arm 35, it will 'be noted, varies approximately directly as the inlet air pressure around the bellows 4|, andinversely as the corresponding temperature; e. g., it varies as the density of the gas or air surrounding the calculator. It is seen'that the ratio arm 35 then is mechanically operated according to the pressure and temperature of the' gas or air whose density is being measured. The angular motion of the ratio arm'35 may be used to position a cam 45 and drive an output connecting rod 45 by means of .the cam Vfollower 4l, and to effect the operation of the connecting'rod` 3| `by means of the cross rod :18. t is noted that the pintle 3l is a xed axis supported within the container I3 but revolvably mounted therein, and 'the connecting rod li slidably operates' through a fixed support 49.

The cam follower di follows the edge 5llof the cam 45 and is revolvably' mounted at 5| in the end of the connecting rod' 46. The cross rod i8 is pivotally connected to sliding block'd'which is slidablyrengaged' with and recipro'cabl'evthin fixed channel guide 52. likewise pivotally connected to'said sliding block '14. are forked to slidably receive the pintles 53 and 5l which are on the ends'of the connecting rods' 45 and 58 respectively.'

From the above it is seen that' the pressure'of the air admitted to the chamber of container I3 through inlet il andthe temperature thereof' operates the density calculator 59. The cal# culator has a mechanical operating' eife'ct'on'the connecting rod 3 I, and servo finger I t' and therethrough the movement of the'Venturi spoon l2 isconformably operated at theV throat iof'the' Venturi meter in accordance with the pressure and temperature of the inlet air from inlet 4D; From thev above it is'seen that the density calculator gives a mechanical indication of the densityof a gas'or'of air and can' .be mechanically used as one of the features or factors" in the operation of the Venturi spoon 2 andthe'.

venturi.

The pressure ratio calculator Connecting rodv 3| is' The ends of the cross'rod '48"' at 51| and EF ratio calculator which comprises two pressure operated bellows 6I and 82. Bellows 92 is encased in a shell 82a and is attached to rod 1I operating through opening 1Ia in shell 82a. The action of these two bellows controls the angular movement of the ratio arm 63 on the axis or pintle 84 which is xedly and revolvably mounted in the closed container I3. The ratio arm 63 is slotted at 65 as shown and the slide 66 operates slidably therein. It will be noted that static gas pressure in the throat i5 of the venturi is taken at points I1 and through the pipe 61 and delivered to the pressure bellows 62 at 68. The pressure bellows B2 is carried pivotally at 69 in the ilxed support 10, which is mounted on the inner face of the wall ofthe closed container I3. It will be at once seen that as the pressure bellows 62 expands or contracts due to the pressure through pipe 61, and affects the operating rod 1I which is pivotally mounted at 12 on the slide 68 that the ratio arm 83 will be angularly operated about the pivot point 64.

The'pressure bellows 6I is actuated by the gas v or air which is within the closed container I3 and comprises the following parts. The pressure bellows 8| is enclosed in the cage 13, and moves the cage 13, which is slidably mounted at 16, 19 on the fixed slide, represented by

rods

15, 15. The wire 11 delivers the response of the pressure bellows 6I to the slide 68 by means of the pulley 18 which is mounted on the xed revolvable pintle 19 carried in the closed container I3. It is noted that the portion 88 of the Iguide wire 11 is in line with the direction slot of the ratio arm G3, and the spring 8l keeps the slack out of the wire 11 when the pull in said wire 11 is lessened by the action of the bellows 8l.

It is then seen that the angular movement of the ratio arm 83 on the pintle 84 is controlled by the joint effect of the two pressure bellows 6I and 62 and in turn, the cam 82 revolves in an arc about the pintle 84. The cam 82 is in continuous engagement with the cam follower 83 which is.

pivotally mounted at 89 in the end of the connecting rod 58 before mentioned. The said rod 58 slidably operates in the xed support 85 and by means of the pintle 51 said rod actuates the cross rod d8 and in turn the connecting rod 3l of the venturi control device by means of the cam 29 and its associated parts.

It will be noted that the angle of rotation of the ratio arm 63 varies approximately directly as the output of the bellows 62 and inversely as the output of the bellows 6I; e. g., as the ratio of the two pressure bellows outputs. The angular mo. tion of the ratio arm, of course, may be used to position a cam, such as 82 to drive an output connection rod 58 and control the parts of a servo iinger apparatus, or for other purposes, such as actuating a suction torque multiplier described below.

Suction torque multiplier The suction torque multiplier I2I just mentioned is intended to produce an angular motion equal to that of an angular input but with much greater torque deriving its operating power from suction gas pressure and from gas pressure surrounding the multiplier device. The device in hand comprises the following parts and is clearly shown in Figs. 3, 4', 5 of the drawings. The input lever 88 (which may be the same as

ratio arms

35 or 93 above described) is revolvably mounted on the cylindrical exterior of the valve section 81. Two

vent slotsV

88, 88 formed in the input lever 6*I 86 act as control valves for this device. The valve section 81 is operable nearly 360 degrees, but if less circular travel is required then said degrees of revolution of the body 81a of the valve section 81 may be cut down to a sector of a cylinder instead of a complete cylinder.

Each of the Valve section vents 89, 89 in section 81 are ducted or lead to one of the

suboperating chambers

98, 98 of the multiplier shown in Figs. 3 and 5 clearly, and said vents are controlled by the input lever 86, depending on the angular position of said lever 86 on the valve section 81 as is at-once understood. In the operating

chambers

98, 98 is located the moving division wall 9| which is preferably made integral with the body of the valve section 81. Centrally of the operating chambers is positioned a nxed shaft 92 (which may be shafts 31 or 8d if so arranged), having a hollow center duct 98 therethrough. A fixed division wall 94 is part of or rigidly mounted on the central shaft 92.

Restricted vents 95, in the central xed shaft 92 provide communication from the operating

chambers

98, 98 to the center or suction duct 93 which is connected to a source of suction by means of pipe |88, which may be joined to a suction conduit such as II or H5, shown in Fig. 1.

It is seenthat when the input lever 88 is given an angular displacement one of the vents 89 is opened partially or fully to one of the proximate corresponding slots 88. This vents one of the operating

chambers

98, 98 to the gas pressure surrounding the device itself, through one of each of the inlet ducts 98,

ducts

88, and 89 shown in Fig. 5 clearly.

It will be noted that when gas pressure is admitted to either of the

chambers

98, 98 the body of the valve section 81 which carries the cam 91 will be thrown into a new angular position on shaft 92 and operate said cam. rEhe moving division wall 9| as well as the iixed division wall 9d are suitably packed at

points

98 and 99 respectively with reference to the exterior periphery of the xed shaft 92, and the interior wall of the valve section body 81a respectively, to reduce gase leakage thereabout. Until the input lever or arm 86 is given an angular displacement and

whileboth ducts

89, 89 are in closed positions both of the operating

chambers

98, 98 are at the suction pressure corresponding to that of the suction duct 93 which is directly connected to the suction pipe IDD. This results from equal venting through the bleeder ports 95,' 95 in the central shaft 92 communicating with suction duct 93. However' when one of the much

larger ducts

89, 89 is opened by means of actuation of the input lever 86, the gas pressure which surrounds the whole torque multiplier causes a gas flow through duct 96, recess 88, and duct 89, into one of the

chambers

98, 98 resulting in a pressure inequality between the two

chambers

98, 98.

However, an appreciable flow of gas escapes through bleeder k95 and an accompanying pressure drop through this bleeder will result, that is to say, the pressurized chamber 99 is at a higher pressure than the suction passage 93. ln this way a pressure inequality is set up between the two

chambers

98, 98. The difference in pressure in the

chambers

98, 98 acting on division wall 9| rotates the body 81a and the valve section 81 tending to unregister

ducts

89 and 98. It to be noted that ports 95 continually vent the pres sure much more slowly than it is built up through inlet duct 89. When

ducts

89 and 96 become unregistered, the remaining pressure is exhausted through bleeder ports 95 vand the rotation of body 87a ceases. As a result, body 87a is rotated an amount approximately equal to the angular displacement of arm 83.

This movement of the kvalve section'87 and body Sla restores its original angular position with respect to input arm 86. Little or no external gas is now admitted to the

chambers

90, 90 through the ducts B9, 89, recesses 33', 83, and pasages- 95, 36; parts accordingly. do' not movel until pressures in chambers 90,V 90 are again unbalanced by motion of input arm 86. The motion of the cam 97 therefore follows the motion of the input arm S6 by means of forces derived from the relative pressures of the suction pipe `|Y and the gas surrounding the torque multiplier, controlled as described above. The motion of the body of the valve section 87a may be used to' operate a cam 97 as shown or to drive an output arm or lever.

It will be noted in the above description two kinds of means are used to operate the cam followers 47 and .03, and connecting rods 45 and 53.

In the rst instance shown in Fig. 1 of the drawings where no suction torque multipliers I2| (Fig. 5) are used, in transmitting motion from ratio arms 35 and 03 to the cam followers 47 and 83 respectively, it is seen, said

arms

35 and 63 are required to be rigidly mounted on said

shafts

37 and 64; likewise cams 50 and 82 are required to be rigidly mounted on said respective shafts.

Shafts

37 and 54 are themselves revolvably mounted in their supports (not shown) so that when

ratio arms

35 and 63 are angularly moved, said cams are correspondingly operated in order to actuate the cam followers 47 and 83, and rods 116 and 58. The selector valve |20, parts H4, H5, and pipes H0 and I I I in this case are eliminated as they are used only when the torque multipliers I2| are used.

In the second case where suction torque multipliers such as IZI (Figs. 3, 4 and 5) are used, conditions are somewhat reversed. The

shafts

37 and 54 which correspond to theshaft 92 of Figs. 3, 4 and 5 are then not made revolvable, and the ratio arms 35 and 53 of Fig. 1 (which correspond to input lever 86, Fig. 3), are made revolvable with reference to

shafts

37 and 64, as is at once understood from the description of suction torque multiplier I2| as explained above. The cams 50 and 82 are also inade revolvable with reference to the

shafts

37 and 64 when the torque multiplier is used in connectionwith the device shown in Fig. 1 of the drawings.

It will be noted in the first instance above men The suction selector valve |20 used with the present invention comprises the following parts. A valve body IIiI is provided having a pair of spaced-apart valve seats |02, |03which are preferably formed integral with the valve body casting ISI. in recesses |05, in the-casing and the .spindle However, the

A valve spindle |04 is slidably mountedv retor in Fig. 1 of theV drawings.

is made shorter in length th'an'the'overall length between the endsr ofthe recesses |05 and |06, leaving a space |07 on either-end of the spindle;

according'to the position of the spindle.

The grooves |08a, Ia' insure the proper ventingof the space |07 between the spindle'ends and the ends of the recesses |05, |06 when the valve is in a'closed position on either side of the valve seat |02 or |03.

The inlet ports |08, |09 are connected with pipes H0, III respectively, and suction port H2 connects with the dual ended pipe H3 whichA forms two branches I I4, H5 leading to the torque multiplier I 2| above described; The valve heads ror discs H6, H7 are arranged to be in contact with either one of the valve seats |03 or |02, but with only one at a time.

The net force or pressure on the valve discs I I6, I I7 moves either one of them and spindle |04 within the valve, toward the side of lower gas pressure as received from pipes H0 or III, seating the valve between the source of higher pressure such as i 09a, in the drawings, and thesuction service connection or suction port I I2. It is.

whichever point in the passage 34 furnishes lower pressure.

The pipes H4 andV H5 lead to the pipe |00l (Fig. 5 of the drawings) of the suction torque multipliers I2I above described and one of which is mounted on each axis 37, and S4 if desired of Fig. 1 of the drawings.

The carburetor assembly The various elements and devices described above are assembled to form a simplified carbu- The Venturi spoon 2 is positioned by the servo finger I4 as before described either manually or automatically,

said nger being mechanically positioned by the.

cam 29. The input to this cam V29T as shown and above described is a function of the sum of the density and pressure ratio corrections above described in connection with the devices shown in and about the closed container I3. Cams 50 and 82 which are attached to the torque multipliers |2I, I2| which are mounted on the shafts 37 and GII, deliver 'appropriate indications to the cani followers VI and 83 and these motions are transmitted by the connection rods d0 and 58, and added by the cross rods 43 and then delivered to the connecting vrod 3| which controls thecam 29,

and hence the servo nnger I and the'Venturi spoon 2 as is readily understood.

It will be noted that while the arrangements have been made for the cams 50 and 82 of Fig. 1 and the cam 37 of the suction torque multiplier, Fig. 3, to push downward the connection rods Ei and 58 and the connecting rod 3| by means of the cross arm 48, it is evident that means'must talfen. This is providedfor by means of a coil spring 23 which is mounted on the pintle 23 which. Thev is carried by the fixed cam'support 2G. said spring 23 bears againstY the outstanding .arm`

d IrlI of thecam 29 at pointI-IZ and pushes the' Y livered across the air diaphragm connecting rod 3| upwards when permitted so to do by the cams above mentioned.

This carburetor arrangement automatically controls the size of the throat l5 leading to the inlet passage 34 and places the Venturi spoon 2 automatically in position according to the combined operation of the various devices such as 59, 60, 3|, I4 as above described. Said devices within the container I3 are, of course, also affected by means of the suction selector valve as before explained. Suction pressure to drive the torque multipliers |2| is taken selectively from the Venturi suction port ||8 or the blower inlet suction port ||9 whichever gives the leser suction pressure.

The selector valve |20, of course, selects the proper source of suction from the ports H8, or IIS fed to the torque multipliers |2|, |2| on the shafts 3'! and 64 (Fig. l), or hollow shaft 32 of Fig. 5.

The metering pressures Pl and P2, taken through parts I3 and Il respectively, are de- |22 in the pressure responsive device |23. The diaphragm |22 which is preferably of stiff materialk is provided with flexible material at |24, |24 between the central stiff portion thereof and the fixed housing |25 to which it is attached. A central valve stem |25 is mounted at |21 on the diaphragm |22 as shown and a suitable yielding packed orifice |28 is used to prevent leakage around said valve stem where it leaves the device |23 as shown.

The metering pressure across the fuel orifice |35 is also across the fuel diaphragm |3|, the total forces on the two diaphragms |22 and |3| are automatically balanced by the action of the fuel regulating valve |37 as long as fuel is supplied to the fuel inlet orice I9 under sufficient pressure. Fuel is delivered to the carburetor passage 34 through the delivery pipe |38.

A butterfly valve may be inserted in the inlet passage 34 if desired for the purpose of controlling the flow of air passing to the engine.

From the above description of the Various parts of the present carburetor arrangement it is seen that a fuel and air mixture is supplied to the engine through the orifice |39 from the passage 34, which is regulated in proportions by a series of factors and devices shown and described in the above specification, and which appear in the Figs. l to 5 of the drawings, practically all of which operate automatically, and provide an almost perfectly balanced fuel and air mixture to the engine, corrected for the effect of pressure, density, temperature and other factors as fully described in the present specification.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental 1G purposes without the payment of any royalties thereon or therefor.

I claim:

l. In a variable area venturi, means for controlling the cross-sectional area of the throat of the venturi, comprising a walled uid carburetor inlet passage having a pocket recess formed therein, a Venturi spoon having a xed vent and a controlled vent therein, an end on the said spoon adapted to reciprocate in the pocket recess, and said spoon being pivotally mounted in proximate relation to the wall of the carburetor passage, a servo nger for controlling the operation of the said spoon and the operative action of the controlled vent, and means for operating the servo finger through the wall of the inlet passage, thereby reciprocating the Venturi spoon to diminish or enlarge the throat of the venturi, and the passage of fluid therethrough.

2. A device according to claim l in which the means for operating the servo finger comprises an outstanding arm having a pintle mounted thereon, a xed cam support, a cam having a curved slot therein pivotally mounted on Said support, said slot being in operative sliding engagement with the pintle of the outstanding arm, and means for revolvably actuating the cam and reciprocating the Venturi spoon in the inlet passage.

3. A device as in claim l in which the controlled vent comprises a pipe mounted in the wall of the Venturi spoon and having perforations near its end, and a closed end on said pipe, said pipe being connected with an opening in the wall of the Venturi spoon for the passage of fluid pressure therethrough; and in which the servo finger in said claim, is provided with a cylinder-shaped end adapted to control the opened area of the perforations in the vent pipe, according to the degree of reciprocation of the servo finger; and in which the means for operating the servo finger comprises a rigid outstanding arm, having a pintle thereon, carried by the servo finger, a fixed cam support, a cam provided with a curved slot pivotally mounted on the cam support, said slot being in engagement with the pintle of the outstanding arm, and means for revolvably actuating the cam and reciprocating the Venturi spoon in the throat portion of the carburetor passage, for the purpose of varying the cross-sectional area of the said throat portion of the venturi.

4. In a variable area Venturi, an air inlet passage means for controlling the cross-sectional area of the throat of the venturi, comprising a walled fluid carburetor inlet passage having a pocket recess formed therein, a Venturi spoon pivotally mounted in proximate relation with the wall of the Venturi passage, an inclined ascending portion in the wall of said spoon having a fixed vent therein, a sharply curved portion on the spoon connected with the said ascending portion of same, a gradually arced portion on the wall of the spoon adapted to reciprocate in the said pocket recess, a controlled vent in the wall ofthe spoon, comprising a dead-ended pipe having a number of perforations therein near said dead or closed end, and an open end on said pipe connected with the air inlet passage, a servo finger pivotally mounted in the wall of the inlet passage, a cylinder-shaped end on said finger adapted to move axially with respect to the inner end of the dead-ended pipe, for controlling the effective area of the perforations in the said pipe,

according to the degree of reciprocation of the servo finger, an outstanding arm on the servo finger, a fixed cam support, a cam having a curved Vslot therein, pivotally mounted on the fixed support, said slot being slidably engaged with the end of the outstanding arm of the servo finger, and means for revolvably operatingthe cam to reciprocate the Venturi spoon and thereby control the cross-sectional area of the throat of the Venturi passage, as well as control the amount of fluid under pressure passing through the wall of the Venturi spoon.

5. in a density calculator a pressure bellows pivotally mounted on a fixed shaft, and adapted to be operated by the pressure of the fluidsurrounding said bellows, an operating rod reciprocatingly actuated by said bellows, a slotted ratio arm mounted on a hollow xed shaft, a slide adapted to reciprocate in theratio arm ,slot in accordance with the temperature surrounding a temperature responsive bimetal coil associated with said s1ide,-said,pressure bellows and bimetal coil co-acting to effect the arm in arcual movement in accordance with the combined effect of the pressure bellows and the bimetal coil; in combination with a suction torque multiplier comprising the aforesaid hollow fixed shaft which is provided with a plurality of restricted vents therein, a body casing revolvably mounted on the central hollow shaft and divided intotwo operating chambers formed by the cooperation of an abutment xed to said shaft and a vane fixed to said casing, a valve section extension on said body having a pair of valve section vents formed therein, the beforementioned arm being revolvably mounted on the valve section extension and having a pair of vent slots which connect the exterior of the ratio arm with an operating chamber of the torque multiplier when the said slots arein registration with the slots of the valve section extension for the purpose of the admission of fluid pressure from the exterior of the device to the operating chambers in the body of the device, and to overcome the normal pressure in one of the operatingrchambers of the torque multiplier which has been admitted through the hollowflxed shaft, Aand thus cause the arcual movement of the body of the multiplier on its central shaft, and a cam on said body adapted to transmit the angular motion of the arm to output devices,

6. A pressure ratio calculator comprising a pressure bellows pivotally mounted on a xed support, a casing surrounding said bellows, an operating rod slidably mounted in said casing and actuated by said bellows, an arm having a longitudinal slot therein, revolvably mounted on a second xed support, a slide adapted to reciprocate in said slot pivotally attached to the operating rodga second pressure bellows mounted on a third xed support, a slidably supported cage attached to the movable end of the second bellows, a pulley mounted on a fourth fixed support, a wire cable attached to the bellows cage passing over said pulley and attached to the slide of the ratio arm, for operating said slide in the arm slot, and a tension spring means mounted on the upper end of the ratio arm and attached to said slide.

7. In a means for operating a Venturi spoon in a carburetor feed device, a pair of revolvable shafts mounted in adjacent relation to each other, an arm rigidly mounted on one'of said shafts, fluid density operated means attached to said arm for arcuately operating said arm and its supporting shaft, a'cam rigidly vmountedon the density operated supporting shaft, a second varm mounted on the companion revolvable shaft, 'fiuid pressure operated means having a motion transmitting member pivotally and slidably connected with the second-named armand obtaining its pressure from a distant source of uid pressure which is conveyed to and within said means, a Vcompanion fluid pressure operated means responsive to pressure immediately surrounding said companion means for sliding said member relative to said second arm, a cam rigidly mounted on the companion shaft, ya-pair of vopposed cam followers each in engagement with one of the pair of cams named herein, a pair of opposed axially slidable connecting rods each revolvably attached to a cam follower at one end and having a pin fixed at the other end, a cross-rod having a pair of slots formed on the ends thereof, each of said slots engaging one of said pins for pivotal connection of the above-named connecting rods, a fixed channel guide, a slidable block in the said guide pivotally connected with said cross-rod, a fixed cam support, a slotted cam pivotally mounted on said cam support and having an extension thereon, a connecting rod pivotally mounted on said cam extension, and pivotally connected to the slidable block operating in said guide, a pivotally mounted Venturi spoon, a servo finger having a servo follow-up connection with said spoon and pivotally mounted on the same axis with the pivoted end of the Venturi spoon, and means on the servo finger adapted to pivotally operate in the slotof said slotted cam, the whole above described device being adapted to actuate the Venturi spoon in accordance with the combined effect of the density and pressure operated means described herein.

8. ln a suction torque multiplier, a hollow fixed shaft lhaving a plurality of restricted bleeder vents therein, a body casing revolvably mounted on said shaft, and divided into two chambers formed by the cooperation of an abutment xed to said shaft and a vane xed to said casing-a valve section extension on said body having a pair of valve section vents formed therein, ran input lever revolvably mounted on the valve section and having a pair of vent slots which connect the exterior of the input lever with one of said operating chambers of the body of the device when said slots are in registration with the slots of the valve section, for the purpose of the admission of gas pressure from the exteriorof the device throughthe hollow fixed shaft to said operating chamber in the body casing for overcoming the normal pressure in said central chamber of the body casing thereby causing arcual movement of the body of the device on its central hollow shaft.

9. In a suction torque multiplier, hollow xed shaft having a plurality of restricted bleeder vents therein, a body casting revolvably mounted on said fixed shaft and divided into two chambers formed by the cooperation of an abutment xed tosaid shaft and a vane fixed to said casing, a valve'section extension on said body casing having a pair `of valve section vents formed therein, an input lever revolvably mounted on the valve section extension having a pair of vent slots, one of each of which'is adapted to connect with one of the valve section extension vents at a time, each'of said invput lever slots connecting with the exterior of 13 the input lever for the admission of gas pressure from the exterior of the device to one of the chambers of the body casing at a time when the input lever vent slots are in registration with the vent slots of the valve section extension.

10. In a density calculator, a pressure bellows pivotally mounted on a xed support, an operating rod reciprocatingly actuated by said pressure bellows, a slotted ratio arm mounted on a revolvable support, a slide pivotally connected to said operating rod adapted to operate with a reciprocating motion in said slot, a bimetal temperature responsive coil mounted on said ratio arm adapted to impart reciprocatory movement to said slide in said ratio arm slot, said pressure bellows and said bimetal coil acting in cooperative relationship to angularly actuate said ratio 14 arm with respect to its revolvable support, cam means provided on said revolvable support, and a cam follower associated with said cam means adapted to be rotated when said cam means is actuated.

ALFRED B. METSGER.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 668,938 Noordaa Feb. 26, 1906 1,913,684 Purdy June 13, 1933 2,036,251 Boynton Apr. '1, 1936 2,305,070 Butler Dec. 15, 1942