US3150601A

US3150601A - Mechanical pump

Info

Publication number: US3150601A
Application number: US122025A
Authority: US
Inventors: Russell F Smith; Eldon A Johnson; Edward M Mason
Original assignee: ACF Industries Inc
Current assignee: ACF Industries Inc
Priority date: 1961-07-05
Filing date: 1961-07-05
Publication date: 1964-09-29
Anticipated expiration: 1981-09-29

Description

Sept. 29, 1964 R. F. SMITH ETAL MECHANICAL PUMP 2 Sheets-Sheet 1 Filed July 5, 1961 4 INVENTORS RUSSELL F. SMITH .ELDON A. JOHNSON EDWARD M. MASON AGENT Sept. 29, 1964 R. F. SMITH ETAL MECHANICAL PUMP 2 Sheets-Sheet 2 Filed July 5, 1961 v INVENTORS RUSSELL F. SMITH ELDON A. JOHNSON I EDWARD M. MASON W AGENT United States Patent O "'ce 3,150,601 MECHANICAL PUIVEP Russell F. Smith, Ferguson, and Eldon A. Johnson and Edward M. Mason, St. Louis County, Mo., assignors to ACF Industries, Incorporated, New York, N.Y., a corporation of New Jersey Filed July 5, 1961, Ser. No. 122,025 Claims. (Cl. 103-150) This invention relates to pumps, and more particularly to a diaphragm pump of a type especially suitable for pumping automotive fuel to the carburetor for an internal combustion engine, the diaphragm of the pump being operable by a drive from the engine.

This application isa continuation-in-part of application Serial No. 764,978, filed October 2, 1958 and now US. Patent No. 3,001,773.

One of the problems occurring with conventional diaphragm fuel pumps is the problem of vaporization of fuel in the pump, with the attendant possibility of interruption of flow of fuel to the carburetor, this being customarily referred to as vapor lock. It will be understood that the fuel is highly volatile, having a tendency to pass from the liquid to the vapor state, which tendency is of course increased by heating. Since the fuel pump is conventionally mounted on the engine to be driven thereby, heat is transferred from the engine to the pump, and thereby to fuel in the pump. Unless this heat is effectively dissipated, vapor lock may occur due to vaporization of fuel in the pump.

Accordingly, one of the objects of this invention is the provision of a pump which, while being of simple, economical construction, is adapted effectively to dissipate heat from the pump so as effectively to reduce the tendency for volatilization of fuel in the pump, thereby to reduce the possibility of vapor lock. In general, this is accomplished by utilizing a pump body of thin-walled heat-conductive construction such as to provide for transfer of heat outward throughthe wall of the body at such a rate as substantially to reduce the tendency for volatilization of fuel within the body. The pump'body is formed to provide a pumping chamber and an intake cavity and a discharge body, and the pump includes a diaphragm closing the pumping chamber, an intake check valve in themtake cavity anda discharge check valve in the discharge cavity. With the body of thin-walled heat-conductive construction, heat is effectively dissipated from the pumping chamber and from the intake and discharge'cavities, thereby maintaining fuel in the pump in a relatively cool state to reduce the tendency toward volatilization such as would otherwise be present. The pump body may be formed of relatively thin sheet metal, which provides for a simple economical construction while at the same time providing for effective heat dissipation. Additionally, the outside surface of the body may be made heat-reflective to decrease the absorbtion of heat by the body from ambient temperatures.

Further objects of the invention are the provision of means in the discharge cavity or in both the discharge and intake cavities for damping pulsations in pressure of fuel delivered by the pump, so as to maintain a more uniform rate of delivery of fuel to the carburetor, and the provision of an improved check valve construction such as to avoid distortion of the check valves when they are assembled with the pump body, thereby to maintain the accuracy of the seats of the check valves. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

3,150,601 Patented Sept. 29., 1964 FIG. 4 is an enlarged vertical cross section of a check valve used in the pump;

FIG. 5 is a bottom plan of the FIG. 4 check valve;

FIG. 6 is a fragmentary vertical cross section of a pump similar to the FIG. 2 and including a first type of pulsation-damping means;

FIG. 7 is fragmentary vertical cross section similar to FIG. 6 illustrating a second type of pulsation-damping means and also illustrating certain modifications in the pump construction;

FIG. 8 is a half-section in perspective of a modified version of the pulsation-damping means of FIG. 7; and

FIG. 9 is a fragmentary vertical cross section similar to FIG. 2 illustrating another type of pulsation-damping means and also illustrating certain modifications in the pump construction.

' Corresponding reference characters indicate correspond parts throughout the several views of the drawings. Referring to FIG. 1 of the drawings, there is indicated at A an automotive vehicle having an engine E on which is mounted a fuel pump P of this invention. Fuel is de' livered from fuel tank T of the vehicle through a line L1 to the fuel pump P and delivered by the latter through a line L2 to the carburetor C for the engine. The carburetor is mounted on the intake manifold of the engine, and an air filter F is shown mounted on the air horn of the carburetor.

As appears in FIGS. 1-3, pump P is a so-called in-' verted pump, i.e., its inlet and outlet are located at the bottom of the pump.' As shown in detail in FIGS. 2 and 3, pump P'comprises a rocker arm housing 1 which is open at one end (its left end as appears in FIG. 2), this end being referred to as the inner end of the housing. This housing is of generally rectangular form in vertical cross section and of decreasing height from its inner end'to its outer end (which is closed). At its inner end it has a flange 3 for attaching it to the engine E. A rocker arm 5 is pivoted at 7 in the housing for rocking moton on a horizontal axis transverse to the housing. Arm 5 has a portion 5a projecting out of the open inner end of the housing, and is biased to rock clockwise as viewed in FIG.

2 by a spring 9. 'When the pump is mounted on the engine, the free end portion 5a of the rocker arm is engaged by an engine-driven eccentric or cam 11. On rotation of the cam through half a revolution from its FIG. 2 position (wherein the low point of the cam engages portion 5a of the rocker arm), the rocker arm is rocked counterclockwise from its FIG. 2 position against the bias of spring 9. The latter is adapted to return the arm thick flat flange 17 at the bottom. The bottom of thisflange constitutes a seating surface for the margin of an annular diaphragm 19 consisting of a relatively thin disk of flexible fuel-resistant material, such as a suitable synthetic rubber, which, when in unstressed condition, is flat or substantially flat. The outer margin of the diaphragm is clamped against the bottom of flange 17 by a pump body 21 which, as illustrated in FIG. 2, is of one-piece thin-Walled sheet metal construction, formed of shallow cup shape, having a bottom or end wall 23 and a flaring, rounded annular peripheral wall 25 defining a pumping chamber 26, with an outwardly extending annular flat flange 27 at the top of wall 25, and a cylindric rim 29. The body 21 is maintained in assembly with head 13 by spinning the rim 29 over on flange 17 of the head as indicated at 31, with the margin of the diaphragm clamped between flange 17 and flange 27 under suflicient pressure to provide a fuel-tight seal all around the margin of the diaphragm.

The diaphragm is adapted to be pulled or flexed upward by a diaphragm-actuating rod 33 and to be flexed downward by a spring 35. Rod 33 extends upward through head 13 and through the opening at the top of the head into the rocker arm housing 1. The rocker arm 5 has a slot 37 at its end in housing 1 receiving the rod 33. The latter has a collar 39 at its upper end engageable by this end of the arm 5. The rod extends slidably through an oil seal and rod guide 41 held in an annular recess at the top of the head 13 by the reaction on a seal retainer ring 43 of the spring 35, this spring being a coil compression spring surrounding the rod. The diaphragm is mounted on the lower end of the rod 33 between a pair of

circular plates

45 and 47, plate 45 being the upper plate and plate 47 the lower plate. upper plate is formed with an annular corrugation or rib 49 forming a seat for confining the lower end of spring 35. The upper plate is of larger diameter than the lower plate and the margin of the upper plate which overhangs the lower plate is flared outward and downward to provide a rim 51 constraining the diaphragm to have an annular, free, nonreversing loop 53. The lower plate has a curved rim 55 engaging the loop. In the downward position of the diaphragm illustrated in FIG. 2, the outside of the loop engages the rounded flaring wall of the pump body 21. When arm 5 is rocked counterclockwise by cam 11, it lifts the rod and pulls the diaphragm upward. This loads the spring 35. Then when arm 5 rocks clockwise, spring is adapted to drive the diaphragm and rod downward.

The sheet metal pump body 21 is formed with two integral deep-drawn rounded-bottom cylindrical

cupshaped projections

57 and 59 extending downward from the bottom Wall 23 of body 21 on opposite sides of the center of the bottom wall. Projection 57 defines an inlet passage or intake cavity 61 and projection 59 defines an outlet passage or discharge cavity 63. An inlet nipple 65 is provided at the lower end of projection 57, and an outlet nipple 67 is provided at the lower end of projection 59. In FIG. 2, inlet nipple 65 is shown as a straight nipple, and outlet nipple 67 is shown as an elbow nipple. It will be understood that, in the installation shown in FIG. 1, supply line L1 is connected to inlet nipple 65 and discharge line L2 is connected to outlet nipple 67.

The

nipples

65 and 67 are fixed to the respective

deepdrawn projections

57 and 59 by inserting the respective collared ends 66 and 68 into a central aperture in the bottoms of the

respective projections

57 and 59 and swaging the metal of the projections tightly against the nipple ends, as shown to form a fuel tight seal. The collared nipple ends 66 and 68 each have grooves formed in the surface of the collars so that the swaged metal is pressed into the grooves to prevent a rotational displacement of the nipples. The sheet metal construction of the pump thus lends itself to a universal adjustment of the nipple 67, for example, in 360 to accommodate any required directional departure of the inlet fuel line L2. In a similar manner nipple 65 may also be formed with an elbow to accommodate any directional approach of inlet line L1.

The

This universal adjustability of the

nipples

65 and 67 provides a flexibility of use with different engine arrangements, which is not available in pumps fabricated from castings.

An intake check valve 69 is provided in the intake cavity 61 and a discharge check valve 71 is provided in the discharge cavity 63. Nipple 65 provides for connection of supply line L1 to intake cavity 61 upstream from the intake check valve 69 and nipple 67 provides for connection of discharge line L2 to discharge cavity 63 downstream from the discharge check valve 71. These check valves are of identical construction. As shown in FIGS. 4 and 5, each check valve comprises a circular sheet metal valve seat 73 having a cylindric rim 75 sized for a press fit in either cavity 61 or cavity 63, as the case may be. Seat 73 has a central hole 77 with an annular boss 79 around the hole extending in the same direction as the rim 75. Surrounding the central hole is a series of ports 31 arranged in a circle around the center hole. The dimension of each of these ports as measured along the stated circle is less than the distance measured radially of the seat 73 from the periphery of the center hole 77 to the periphery of the seat 73. More particularly, the ports are circular holes of smaller diameter than the center hole. They are equally and closely spaced around the stated circle at intervals such as to leave spoke-like portions 82 of the valve seat 73 between the ports with these spoke-like portions narrower than the diameter of the ports. Seat 73 is preferably dished inwardly to a slight extent in the direction in which rim 75 and boss 79 project therefrom (i.e., downwardly dished as viewed in FIG. 4). This dishing may be of the order of 1 /2, for example. Fitted in the boss 79 is a hollow sheet metal stem 83 which is closed at its lower end as indicated at 85 in FIG. 4. Stem 83 has an apertured mushroom head 87 at its other end constituting a spring seat. A ring-shaped disk valve member 89, which may be made of a suitable fuel-resistant synthetic rubber for cushioned sealing, is slidable on the stem and is biased toward engagement with the valve seat by a coil compression spring 91 surrounding the stem and reacting from the head 87. In assembling the stem with the valve seat, the stem 83 is pressed in the central hole 77 in the valve seat and the closed end of the stem is deformed as indicated at 93 to lock the stem in the seat and seal the central hole.

The intake check valve 69 is pressed in the intake cavity 61 with its stem 83 extending upward and the discharge check valve 71 is pressed in the discharge cavity 63 with its stem extending downward (see FIG. 2). It has been found that, with the ports in the valve seat formed as herein described, rather than being formed as relatively long slots in the valve seat, stresses such as would cause distortion of the valve seats during the operation of pressing the seats into the cavities are avoided, and the original accuracy of the seats is preserved. At the same time, the total port area is adequate for flow of fuel.

In the operation of the pump shown in FIG. 2, diaphragm 19 is flexed up and down by the action of cam 11 and spring 35. On an upward (suction) stroke of the diaphragm, the intake check valve 69 opens and the discharge check valve 71 closes, and fuel is drawn into the pumping chamber 26 below the diaphragm. On a downward (discharge) stroke of the diaphragm, the intake check valve 69 closes and the discharge check valve 71 opens, and fuel is forced out through line L2 to the carburetor. Since the pump body 21 is formed of sheet metal, it is of thin-walled heat-conductive construction such as to provide for transfer of heat outward therethrough at such a rate as substantially .to reduce the tendency for volatilization of fuel within the body, thereby reducing the possibility of vapor lock. In this respect, it will be observed that heat transmission occurs not only through

walls

23 and 25 of pumping chamber 26 but also through the walls and bottoms of

projections

57 and 59, all of which are thin-walled, so

that heat is dissipated at a relatively rapid rate. The rate may be increased by making the outer surface of the pump body heat-reflective, as by bright zinc plating of the exterior of the pump body. With such plating, heat is reflected from the body for cooler operation of the pump and increased transmission of heat from fuel in the pump body to the exterior.

Making the pump body of sheet metal not only pro vides a thin-walled construction for effective heat dissipation, but also provides an economical construction, the pump body itself being economical to manufacture and economical to assemble with the rocker arm housing 1, the assembly operation simply involving the spinning over of rim 29 of the pump body on flange 17 of the head 13. A typical pump body having a diameter (measured at rim 29) of three and one-half inches may be made of suitable steel plate 0.035 inch thick, for example. In general, the advantages of the invention may be a-t tained with a pump body having a wall thickness less than 0.050 inch.

FIG. 6 illustrates a pump similar to that shown in FIG. 2 provided with means for damping pulsations in pressure of fuel delivered by the pump so as to maintain a more uniform rate of delivery of fuel to the carburetor. As shown in FIG. 6, the cup-shaped projections of the pump body 21 are drawn deeper than in FIG. 2, and are designated 57a and 59a. In each cup is press-fitted a partition 101 having a central hole 103 and a circular series of ports 105 around the central hole 103. The portion of the partition around the center hole is cupped as indicated at 107 to form a seat for a hollow resilient compressible ball 109 which may be made, for example, of a suitable fuel-resistant synthetic rubber. In the intake cup 57a the partition is arranged with seat 107 extending upward and ball 109 below the partition. In the discharge cup 59a, the partition is arranged with seat 107 extending downward and ball 109 above the partition. The hollow resilient compressible balls 109 act like air chambers or air domes to damp pulsations of pressure of fuel in the intake and discharge cavities by contract-ion and expansion thereof, and tend to equalize pressure of fuel delivered to the carburetor.

FIG. 7 illustrates a modification in which the cupshaped projections of the pump body 21 are constituted by separately formed cup members 57b and 5%. Each of these has an outwardly extending rim 111 at its upper end and extends down through an opening 113 provided in the bottom wall 23 of the pump body, the rims engaging the bottom wall 23 and being suitably soldered thereto. This three-piece type of construction for the pump body 21 has the advantage over the one-piece type of pump body shown in FIG. 6, for example, in that, for a given cup height, it permits the cups to be arranged closer together, as may be desirable. In this respect, it will be observed that with deep-drawn integral cups as in FIG. 6, it is necessary that the cups be relatively widely spaced to permit deep drawing.

FIG. 7 also illustrate another type of pulsation damping means comprising an annular hollow resiliently compressible member 121 axially positioned in each projection 57b and 59b, each of these members being made, for example, of a suitable fuel-resistant synthetic rubber. The central passages 125 through these members provide for flow of fuel, and pulsations are damped by contraction and expansion of the members, which act like air chambers or air domes.

FIG. 8 illustrates a modification of the pulsation damping members of FIG. 7, showing an annular resiliently compressiblemember 121a made of closed-cell foam rubber of a fuel-resistant variety. Such members may be conveniently obtained by segmenting an extruded tube of the closed-cell foam rubber material. They are placed in cups 57b and 59b in the same manner as members 121 shown in FIG. 7.

FIG. 9 illustrates another arrangement for pulsation damping on the discharge side of the pump only. As shown therein, the intake cup, designated 57c, is a rela tively short cup (as in FIG. 2), formed as a separate piece and soldered to the pump body as in FIG. 7. The discharge cup comprises a shell 131 having a cylindric upper end portion 133 received in an opening in the bot-tom wall 23 of pump body 21 in the same manner as in FIG. 7, and a flaring lower portion 135. The discharge check valve 71 is pressed into the cylindric portion 133. The flaring lower portion has an outwardly projecting flat annular flange 137 at its lower end constituting a seating surface for a diaphragm 139 made, for example, of a suitable fuel-resistant synthetic rubber. The outer margin of the diaphragm is clamped against the bottom of flange 137 by the rim 141 of an inverted dome 143 and the parts are held in assembly by spinning a rim 145 on flange 137 over on the rim 141 of the dome. The diaphragm 139 and the dome provide an air chamber 147 sealed off from the shell 131, pulsations being damped by flexing of the diaphragm. The discharge nipple 149 is connected to shell 131 above the diaphragm 139.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A diaphragm pump for pumping a volatile liquid, said pump comprising a pump head, a pump body secured to said pump head, said pump body being formed from a single piece of sheet metal into a single walled cup having a circular flange around the lip of the cup, a diaphragm assembly including a circular diaphragm of flexible fuel resistant material extending across said pump body and having its peripheral margin clamped between said circular flange and said pump head, said body cup having an end wall and an annular peripheral wall between said end wall and said circular flange defining with said diaphragm a pumping chamber, said body having a pair of closed tubular projections extending outwardly from said end wall and opening into said pumping chamber, said tubular projections each having a passage through the wall thereof, a coil spring within said head biasing said diaphragm assembly toward said end wall, a circular plate coaxially fixed to said diaphragm between said spring and said diaphragm, said plate extending across said pumping chamber and having a marginal edge spaced from said annular cup wall and formed with a rim flared toward said pumping chamber for moving the annular portion of said diaphragm adjacent to the peripheral margin thereof against and into contact with said annular peripheral body wall to force fuel out of said pumping chamber into one of said tubular projections, said dia phragm assembly including a rod to move said diaphragm assembly against said spring bias to move said annular diaphragm portion away from said annular body wall to draw fuel into said pumping chamber from the other one of said tubular projections, an inlet check valve means within said other one of said tubular projections for controlling fluid flow through said passage thereof, and outlet check valve means for controlling the flow of fluid through said passage in said one of said tubular projections.

2. A diaphragm pump as set forth in claim 1 wherein said tubular projections are formed as integral parts of said body.

3. A diaphragm pump as set forth in claim 1 wherein said body comprises a first part formed to provide said annular peripheral wall and said end wall and second and third parts formed to provide said tubular projections and secured to said end wall.

4-. A diaphragm pump for pumping a volatile liquid, said pump comprising a pump head, a pump body secured to said pump head, said pump body being formed from a single piece of sheet metal into a single walled cup having a circular flange around the lip of the cup, a diaphragm assembly including a circular diaphragm extending across said pump body and having its peripheral margin clamped between said circular body flange and said pump head, said body cup having an end wall and an annular peripheral wall between said end wall and said circular flange defining with said diaphragm a pumping chamber, said body having a pair of sheet metal closed tubular projections extending outwardly from said end wall and opening into said pumping chamber, said tubular projections each having a passage through the wall thereof, a coil spring within said head biasing said diaphragm assembly toward said end wall, a circular plate coaxially fixed to said diaphragm between said spring and said diaphragm, said plate extending across said pumping chamber and having a marginal edge spaced from said annular cup wall and formed with a rim flared toward said pumping chamber for moving the annular portion of said diaphragm adjacent to the peripheral margin thereof against and into contact with said annular peripheral body wall to force fuel out of said pumping chamber into one of said tubular projections, said diaphragm assembly including means to move said diaphragm assembly against said spring bias to move said annular diaphragm portion away from said annular body wall to draw fuel into said pumping chamber from the other one of said tubular projections, an inlet check valve means within said other one of said tubular projections for controlling fluid flow through said passage thereof, and an outlet check valve means within the said one of said tubular projections for controlling the flow of fluid through said passage thereof, said peripheral body wall and said tubular projections being outer exposed walls of said pump.

5. A diaphragm pump as set forth in claim 4 wherein said tubular projections are formed as integral parts of said body.

6. A diaphragm pump for pumping a volatile liquid, said pump comprising a pump head having an opening with a flange therearound, a sheet metal pump body having an opening with a rim therearound mounted across said flanged opening of said pump head, said head flange being relatively thick compared with the thickness of the sheet metal of said body, a diaphragm assembly including a circular diaphragm of flexible fuel resistant material extending across the opening of said pump body and having its peripheral margin clamped between said pump body rim and said pump head flange, said sheet metal body rim enclosing said head flange to secure said body to said head, said sheet metal body having an end wall and an annular peripheral wall between said end wall and said diaphragm defining with said diaphragm a pumping chamber, said body having a pair of cup-shaped sheet metal projections extending outwardly from said end wall and opening into said pumping chamber, said cupshaped projections each having a passage through the wall thereof, a coil spring within said head biasing said diaphragm assembly toward said end wall with the annular portion of said diaphragm adjacent to the peripheral margin thereof lying against said annular peripheral body wall, said diaphragm assembly including a rod to move said diaphragm assembly against said spring bias, an inlet check valve means within one of said cup-shaped projections for controlling fluid flow through said passage thereof, and outlet check valve means for controlling the flow of fluid through said passage in the other one of said cup-shaped projections.

7. A diaphragm pump for pumping a volatile liquid, said pump comprising a pump head having an opening with a flange therearound, a sheet metal pump body having an opening with a rim therearound mounted across said flanged opening of said pump head, said head flange being thick relative to the thickness of the sheet metal of said body, a diaphragm assembly including a pair of circular plates and circular diaphragm of flexible fuel resistant material coaxially mounted with its central portion fixed between said plates, said diaphragm extending across the opening of said pump body and having its peripheral margin clamped between said pump body rim and said pump head flange, said sheet metal body rim enclosing said head flange to secure said body to said head, said sheet metal body having an end wall and an annular peripheral wall between said end wall and said diaphragm defining with said diaphragm a pumping chamher with one of said pump assembly plates within said pumping chamber, said body having a pair of cup-shaped sheet metal projections extending outwardly from said end wall and opening into said pumping chamber, said cup-shaped projections each having a passage through the wall thereof, a coil spring within said head biasing said diaphragm assembly toward said end wall with the annular portion of said diaphragm adjacent to the peripheral margin thereof lying against said annular peripheral body wall, said one plate having a curved rim projecting into said pumping chamber, the other one of said plates having a curved rim extending over the rim of said one plate, said diaphragm extending between said rims and being directed by said rims into an annular loop extending between said plate rims and said annular peripheral body Wall, said diaphragm assembly including a rod connected to said plates to move said diaphragm assembly against said spring bias, an inlet check valve means within one of said cup-shaped projections for controlling fluid flow through said passage thereof, and an outlet check valve means within the other one of said cup-shaped projections for controlling the flow of fluid through said passage thereof.

8. A diaphragm pump for pumping a volatile liquid, said pump comprising a pump head, a pump body secured to said pump head, said pump body being formed from a single piece of sheet metal into a single walled cup having a flange around the lip of the cup, a diaphragm assembly including a pair of plates and a diaphragm coaxially mounted with its central portion fixed between said plates, said diaphragm extending across said pump body and having its peripheral margin clamped between said body flange and said pump head, said body cup having an end wall and an outwardly flaring wall between said end wall and said body flange defining with said diaphragm a pumping chamber with one of said pump assembly plates within said pumping chamber, said one plate having a curved rim projecting into said pumping chamber, the other one of said plates having a curved rim extending over the rim of said one plate, said diaphragm extending between said rims and being directed by said rims into a continuous loop extending between said plate rims and said outwardly flaring body wall, said body having a pair of cup-shaped sheet metal projections extending outwardly from said end wall and opening into said pumping chamber, said cup-shaped projections each having a passage through the wall thereof, an

outlet check valve means within one of said cup-shaped.

projections for controlling fluid flow through said passage thereof, and an inlet check valve means within the other one of said cup-shaped projections for controlling the flow of fluid through said passage thereof, and a coil spring within said head biasing said diaphragm assembly toward said end wall with the outer wall of said diaphragm loop against and into contact with said outwardly flaring body wall to force fuel out of said pumping chamber into said one of said cup-shaped projections, said diaphragm assembly including a rod connected to said plates to move said diaphragm assembly against said spring bias and to move said diaphragm loop away from said outwardly flaring body wall to draw fuel into said pumping chamber from said other one of said cup-shaped projections.

9. A diaphragm pump for pumping a volatile liquid, said pump comprising a pump head, a pump body secured to said pump head, said pump body being formed from a single piece of sheet metal into a single walled cup having a circular flange around the lip of the cup, a diaphragm assembly including a pair of circular plates and a circular diaphragm coaxially mounted with its central portion fixed between said plates, said diaphragm extending across said pump body and having its peripheral margin clamped between said circular body flange and said pump head, said body cup having an end wall and an annular outwardly flaring wall between said end wall and said circular flange defining with said diaphragm a pumping chamber with one of said pump assembly plates within said pumping chamber, said one plate having a curved rim projecting into said pumping chamber, the other one of said plates having a curved rim extending over the rim of said one plate, said diaphragm extending between said rims and being directed by said rims into a continuous annular loop extending between said plate rims and said outwardly flaring body wall, said body having a pair of cup-shaped sheet metal projections extending outwardly from said end wall and opening into said pumping chamber, said cup-shaped projections each having a passage through the Wall thereof, an outlet check valve means within one of said cup-shaped projections for controlling fluid flow through said passage thereof, and an inlet check valve means within the other one of said cup-shaped projections for controlling the flow of fluid through said passage thereof, a coil spring within said head biasing said diaphragm assembly toward said end wall for moving the outer wall of said diaphragm loop against and into contact with said outwardly flaring body wall to force fuel out of said pumping chamber into said one of said cup-shaped projections, and means to move said diaphragm assembly against said spring bias and to move said diaphragm loop away from said outwardly flaring body wall to draw fuel into said pumping chamber from said other one of said cup-shaped projections.

10. A diaphragm pump for pumping a volatile liquid, said pump comprising a pump head, a pump body secured to said pump head, said pump body being formed from a single piece of sheet metal into a single thin walled cup having a circular flange around the lip of the cup, a diaphragm assembly including a pair of circular plates and a circular diaphragm coaxially mounted with its central portion fixed between said plates, said diaphragm extending across said pump body and having its peripheral margin clamped between said circular body flange and said pump head, said body cup having an end wall and an annular peripheral wall between said end wall and said circular flange defining with said diaphragm a pumping chamber with one of said pump assembly plates within said pumping chamber, said one plate having a curved rim projecting into said pumping chamber, the other one of said plates having a curved rim extending over the rim of said one plate, said diaphragm extending between said rims and being directed by said rims into a continuous annular loop extending between said plate rims and said annular peripheral body wall, said body having a pair of tubular sheet metal extensions formed outwardly from said end wall and each opening at one end into said pumping chamber, said tubular extensions each being closed and having a passage through the wall thereof, an outlet check valve means within one of said tubular ex tensions for controlling fluid flow through said passage thereof, and an inlet check valve means within the other one of said tubular extensions for controlling the flow of fluid through said passage thereof, a coil spring within said head biasing said diaphragm assembly toward said end wall for moving the outer wall of said diaphragm loop against and into contact with said annular peripheral body wall to force fuel out of said pumping chamber into said one of said tubular extensions, and means to move said diaphragm assembly against said spring bias and to move said diaphragm loop away from said annular body wall to draw fuel into said pumping chamber from said other one of said tubular extensions, said annular peripheral body wall and said tubular extensions being outer exposed walls of said pump.

References Cited in the file of this patent UNITED STATES PATENTS 406,273 Everett July 2, 1889 1,976,520 Rockwell Oct. 9, 1934 2,803,265 Coffey Aug. 20, 1957 2,840,003 Johnson et al. June 24, 1958 2,856,862 Korte Oct. 21, 1958 2,902,988 Rippingille Sept. 8, 1959 2,905,097 Johnson Sept. 22, 1959 2,918,091 Borden Dec. 22, 1959 2,969,745 Johnson et a1. Jan. 31, 1961 FOREIGN PATENTS 621,906 Canada June 13, 1961 83,399 Sweden Mar. 14, 35

Claims

1. A DIAPHRAM PUMP FOR PUMPING A VOLATILE LIQUID, SAID PUMP COMPRISING A PUMP HEAD, A PUMP BODY SECURED TO SAID PUMP HEAD, SAID PUMP BODY BEING FORMED FROM A SINGLE PIECE OF SHEET METAL INTO A SINGLE WALLED CUP HAVING A CIRCULAR FLANGE AROUND THE LIP OF THE CUP, A DIAPHRAGM ASSEMBLY INCLUDING A CIRCULAR DIAPHRAGM OF FLEXIBLE FUEL RESISTANT MATERIAL EXTENDING ACROSS SAID PUMP BODY AND HAVING ITS PERIPHERAL MARGIN CLAMPED BETWEEN SAID CIRCULAR FLANGE AND SAID PUMP HEAD, SAID BODY CUP HAVING AN END WALL AND AN ANNULAR PERIPHERAL WALL BETWEEN SAID END WALL AND SAID CIRCULAR FLANGE DEFINING WITH SAID DIAPHRAGM A PUMPING CHAMBER, SAID BODY HAVING A PAIR OF CLOSED TUBULAR PROJECTIONS EXTENDING OUTWARDLY FROM SAID END WALL AND OPENING INTO SAID PUMPING CHAMBER, SAID TUBULAR PROJECTIONS EACH HAVING A PASSAGE THROUGH THE WALL THEREOF, A COIL SPRING WITHIN SAID HEAD BIASING SAID DIAPHRAGM ASSEMBLY TOWARD SAID END WALL, A CIRCULAR PLATE COAXIALLY FIXED TO SAID DIAPHRAGM BETWEEN SAID SPRING AND SAID DIAPHRAGM, SAID PLATE EXTENDING ACROSS SAID PUMPING CHAMBER AND HAVING A MARGINAL EDGE SPACED FROM SAID ANNULAR CUP WALL AND FORMED WITH A RIM FLARED TOWARD SAID PUMPING CHAMBER FOR MOVING THE ANNULAR PORTION OF SAID DIAPHRAGM ADJACENT TO THE PERIPHERAL MARGIN THEREOF AGAINST AND INTO CONTACT WITH SAID ANNULAR PERIPHERAL BODY WALL TO FORCE FUEL OUT OF SAID PUMPING CHAMBER INTO ONE OF SAID TUBULAR PROJECTIONS, SAID DIAPHRAGM ASSEMBLY INCLUDING A ROD TO MOVE SAID DIAPHRAGM ASSEMBLY AGAINST SAID SPRING BIAS TO MOVE SAID ANNULAR DIAPHRAGM PORTION AWAY FROM SAID ANNULAR BODY WALL TO DRAW FUEL INTO SAID PUMPING CHAMBER FROM OTHER ONE OF SAID TUBULAR PROJECTIONS, AN INLET CHECK VALVE MEANS WITHIN SAID OTHER ONE OF SAID TUBULAR PROJECTIONS FOR CONTROLLING FLUID FLOW THROUGH SAID PASSAGE THEREOF, AND OUTLET CHECK VALVE MEANS FOR CONTROLLING THE FLOW OF FLUID THROUGH SAID PASSAGE IN SAID ONE OF SAID TUBULAR PROJECTIONS.