US3301190A

US3301190A - Foot operated hydraulic pump

Info

Publication number: US3301190A
Application number: US421315A
Authority: US
Inventors: John T Gondek
Original assignee: OIL DYNE Inc
Current assignee: OIL DYNE Inc
Priority date: 1964-12-28
Filing date: 1964-12-28
Publication date: 1967-01-31
Anticipated expiration: 1984-01-31

Description

United States Patent 3,301,190 FOOT OPERATED HYDRAULIC PUMP John T. Gondek, Minneapolis, Minn., assignor to Oil- Dyne, Inc., a corporation of Minnesota Filed Dec. 28, 1964, Ser. No. 421,315 2 Claims. (Cl. 103-42) This invention relates to an improvement in foot operated hydraulic pump and deals particularly With a simple and effective pump useful in supplying fluid under high pressure to various instruments and devices such as to operate hypodermic syringes used by veterinarians and the like.

An object of the present invention resides in the provision of a simple pump having a reciprocal pump piston against which considerable force may be exerted by means of a foot actuated pedal or lever. The operating lever projects laterally from the pump housing and is pivoted to the housing on an axis in a plane substantially normal to the axis of the piston or plunger. The piston extends from the housing and is engaged by a roller supported by the foot lever on an axis parallel to the pivot axis of the lever. The distance between the axes of the lever and the roller is short relative to the length of the foot lever, thereby multiplying the force exerted upon the foot lever.

A further feature of the present invention resides in the provision of a pump housing having a removable cover plate, the cylinder supporting the piston extending into the housing and the interior of the housing on both sides and above the cylinder forming a fluid reservoir. A diaphragm of a flexible nature is supported between the top cover plate and the remainder of the housing to provide a liquid chamber which may vary in size. An air chamber is provided between the cover plate and the diaphragm, and a vent aperture is provided between the air chamber and the outer atmosphere to permit the flexing of the diaphragm with changes in the volume of liquid within the reservoir.

A further feature of the present invention resides in the provision of a foot pump of the type described in which the piston is normally urged in an outward direction by spring pressure and is urged inwardly by movement of the foot lever. During the power stroke of the piston, liquid under pressure is forced past a check valve to the operated device. Liquid returns from the operated device to the reservoir. During the return stroke of the piston, liquid is drawn from the reservoir into the cylinder past another check valve.

-A feature of the present invention resides in the provision of a foot operated pump particularly designed for use in a closed system where a low volume of liquid under high pressure is required. In the preferred form of invention, about one-half of a cubic inch of liquid is pumped during each power stroke, but the liquid is pumped under a pressure of several hundred pounds per square inch. For example, the relief valve which permits the bypassing of the oil under abnormal pressure conditions may be set to open at eighteen hundred pounds per square inch pressure. The pump normally delivers fluid under pressure up to this amount before bypassing.

These and other Objects and novel features of the present invention will be more clearly and fully set forth in the following specification and claims.

In the following specification and claims;

FIGURE 1 is a side elevational view, partly in section, showing the pump construction.

FIGURE 2 is a horizontal sectional View through the pump, a portion of the operating foot lever being shown in top plan.

The pump A includes an open top housing having a bottom closure plate 11 and upwardly extending peripheral walls 12 thereupon which terminatein a flat ice upper surface 13. A mounting flange 14 projects forwardly from the lower portion of the housing and is provided with spaced apertures 15 therethrough for the accommodation of mounting bolts. A mounting flange 16 also extends rearwardly from the lower portion of the housing 10 and is provided with an aperture 17 designed to accommodate a mounting bolt. Reinforcing gusset plates 19 connect the flange 16 with the side walls 12, the gusset plates 19 being in spaced relation along opposite sides of the generally rectangular flange 16.

A substantially semi-cylindrical boss 20 extends from front to rear of the housing on the bottom closure plate 11. The front portion of the peripheral wall 12 is greatly thickened as indicated at 21 to provide space for a pair of check valves and a pressure relief valve. A cylindrical bore 22 extends into the boss 20 from the rear side of the housing, and is open to atmosphere above the flange 16 and between the gusset plates 19. A piston or plunger 23 is axially slidable in the cylindrical bore 22. The forward end of the piston 23 is provided with an axial cylindrical socket 24 which terminates short of the rear or outer extremity 25 of the piston 23. An axial socket 26 is also provided in the thickened wall portion 21 at the end of the cylindrical bore 22. A spring 27 is interposed between the base of the socket 26, and the base of the piston socket 24, the spring 27 urging the piston 23 rearwardly or outwardly from the housing.

A cover plate 29 having a slightly hollow under surface 30, and having a downwardly extending peripheral flange 31 terminating in a common horizontal plane is supported upon the top of the housing 10. The cover plate 29 corresponds in outline shape to the shape of the generally cylindrical upper end of the housing 10. A flexible diaphragm 32 is clamped between the cover plate 29 and the upper surface 13 of the housing 10 by cap screws 33 or the like. A vent passage 34 is provided in the closure plate 29 to permit the passage of air into the space between the diaphragm 32 and the cover plate 29. As a result, the diaphragm may be flexed by changes in volume of the liquid contained.

A pair of parallel arms, one of which is shown at 35, project rearwardly from the walls 12 of the housing 10, the arms 35 being joined along their lower edges to the gusset plates 19 for support thereby. The arms 35 are on opposite sides of a vertical plane through the axis of the cylindrical bore 22. A foot pedal indicated in general by the numeral 36-extends between the spaced arms 35 and is pivotally connected thereto by a pivot pin 37. The foot pedal 36 is shown generally triangular or tapered form being widest at the end adjoining the pump body and substantially narrower at the free outer end. In the form illustrated, the pedal 36 is somewhat similar to an eye beam in vertical section, including a peripheral web 39 of substantial width, and a thinner web 40 enclosed by the peripheral edge 39. A foot engaging end 41 is supported upon the rear end of the pedal 36, the member 41 preferably having a convex upper surface 42 against which the shoe of the operator may engage regardless of the angularity of the foot pedal. Reinforcing gussets 43 extend from opposite sides of the wider foot engagingend 41 to strengthen the structure.

The foot pedal 36 is provided with a forward projection 44 extending forwardly from the upper surface of the pedal to engage inclined lug 45 on the center portion of the housing wall 12 between the arms 35. The engagement of the projection 44 with the lug 45 limits the pivotal movement of the foot pedal 36 in a counterclockwise dithe roller. The roller 47 is positioned to engage the rear or outer end 25 of the piston 23 to provide a relatively frictionless engagement between the foot pedal 36 and the piston 23.

Thus it will be seen that by applying downward pressure on the foot plate 41 of the foot lever 36, the piston 23 may be moved axially in a direction to force fluid from the cylinder or cylindrical bore 22. Suitable sealing rings 48 are provided in a peripheral groove 50 communicating with the bore 22 to seal the piston 23 with respect to the cylinder.

As indicated in FIGURE 1 of the drawings, a vertical passage 52 extends upwardly from the socket 26 in a communication with relatively large diameter bore 53, the tapered lowered end 54 of the bore 53 serving as a valve seat for a valve ball 55. The valve ball 55 is held against the valve seat 54 by means of a plunger 56 slidable in the bore 53 and having peripheral grooves 57 to permit the bypass of fluid when the ball 55 is not engaged with its valve seat 54. A plug 59 is threaded into the upper end of the bore 53 and includes a multi-sided aperature 60 extending therethrough which serves as a fluid passage as well as a means of receiving an Allen wrench or the like for rotating the plug 59. A spring 61 is interposed between the plug 59 and the plunger 56, the spring encircling an upwardly extending shank forming a part of the plunger for holding the spring and plunger aligned. The plunger 56 is provided with a concave lower end 62 to accommodate the valve ball 55. The valve ball 55 forms a pressure relief valve which will open when the pressure in the socket 26 reaches a predetermined maximum in order to permit the bypass of liquid past the valve. As will be noted, the upper end of the bore 53 is open to the reservoir which is indicated in the drawings by the numeral 63.

As indicated in FIGURE 2 of the drawings, a passage 64 extends from the cylindrical bore 22 to a right angularly extending larger diameter bore 65 extending into the housing from the rear thereof. The bore 65 is connected with an axially extending small diameter passage 66 by a tapered valve seat 67. A valve plunger 69 having a longitudinally grooved peripheral surface is slidably supported in the bore 65 and is provided with a tapered end 70 designed to seat against the valve seat 67. An ring 71 is provided in a groove in the tapered end 70 to prevent leakage between the plunger and the seat when the valve plunger is in closed position.

The valve plunger 69 is normally held against its seat 67 by a spring 72 which has one end extending into the socketed end 73 of the plunger 69, and the other end of which extends into the socketed end 74 of a removable plug 75. Thus the plunger 69 forms a check valve capable of opening during the return stroke of the piston 23. As noted, the passage 66 leads to the reservoir chamber 63, while the opposite side of the plunger 69 is subject to pressure in the passage 64 communicating with the cylinder 22.

An additional passage 76, aligned with the passage 64, communicates with the interior of the cylinder 22. The passage 76 is connected to a larger diameter bore 77 leading through the wall 12 of the housing by a tapered valve seat 79. A plunger 80 having a grooved outer surface is slidable in the bore 77 and is provided with a tapered end 81 designed to seat against the valve seat 79. An O-ring 82 is supported by the tapered end 80 to form an effective seal between the plunger and the valve seat.

The plunger 80 is normally held against the valve seat by a spring 83 which extends into the socketed end 84 of the plunger 80 and the opposed socketed end 85 of a hollow screw fitting 86. The fitting 86 projects from the housing 10 and is designed to accommodate a pressure hose for pipes.

An internally threaded passage 87 extends through the wall 12 of the housing 10 into communication with reserend is designed to accommodate a pressure hose or pipe through which liquid may flow into the reservoir 63.

An internally threaded passage 90 extends through the casing wall 12 in opposed relation to the passage 87 and is designed to accommodate a screw plug 91. The plug 91 is provided to facilitate the filling of the housing.

The operation of the pump is believed readily understandable from the foregoing description. In usual practice, the fitting 86 is connected by a suitable pressure pipe or hose to an instrument or apparatus requiring a small volume of hydraulic fluid to operate where high pressure is usually required. The fitting 89 is connected by a suitable pressure hose or the like to the outlet of the instrument or other apparatus. Downward pressure upon the treadle and 41 of the foot pedal 36 swings this foot lever in a clockwise direction, the roller 47 engaging against the end of the plunger or piston 23, and urging the piston to the left as viewed in the drawings. This action causes fluid under pressure to open the discharge valve 80 and flow past this valve into the hose connected to the fitting 86.

When pressure on the foot pedal 36 is released, the foot pedal is returned to its original position by the spring 27. Movement of the piston 23 to the right as viewed in the drawings, creates a source of partial vacuum in the cylinder 22 which is communicated through the passage 64 to the bore 65. This causes the valve plunger 73 to open, allowing hydraulic liquids to be drawnthrough the pass age 66, past the plunger 73 and the passage 64 into the cylinder 22.

In actual practice the pump is filled by turning the housing on its side and filling the reservoir 63. When fluid is pumped from the reservoir by the piston 23, the diavoir 63. The fitting 89 is hollow, and the outer threaded phragm may flex downwardly to some extent. In other instances, such as during filling the diaphragm may flex in the opposite direction. The diaphragm permits fluid to be forced from, or returned to, the reservoir.

In the event the driven unit fails to function so that abnormal pressures are built up within the cylinder 22, the pressure relief valve ball 55 may open to permit the bypass of fluid back into the reservoir 63.

In accordance with the patent statutes, the principles of construction and operation of this improvement in Foot Operated Hydraulic Pump have been described, and while an endeavor has been made to set forth the best embodiment thereof, it should be understood that changes may be made within the scope of the following claims without departing from the spirit of the invention.

The claims:

1. A foot actuated pump comprising:

a housing including a reservoir,

a cylinder in said housing having one end open to atmosphere, the cylinder having a generally hori zontal axis,

a piston slidable in said cylinder and including means projecting from said open end,

a foot lever pivotally connected to said housing on a generally horizontal axis above said cylinder and in a plane normal to the axis of the cylinder,

roller means on said foot lever beneath said pivot axis and parallel thereto engaging the projecting end of said piston and operable to move said piston toward the other end of said cylinder upon pivotal movement of said foot lever,

cooperable means on said lever and on said housing limiting pivotal movement of said foot lever in a direction to limit outward movement of said piston,

resilient means normally urging said piston against said means on said foot lever,

said housing having an outlet passage from said other end of said cylinder, and said housing including an inlet passage from said reservoir to said other end of said cylinder and including a check valve permitting a flow of liquid to, but not from, said cylinder, and

said housing including a separate return passage communicating with said reservoir,

said housing including a diaphragm extending across said housing dividing the interior of the housing into a liquid chamber and an air chamber, said housing including a vent opening connecting said air chamber with atmosphere.

2. A foot actuated pump including:

a housing including a reservoir,

:1 cylinder in said housing having an end open to atmosphere, the cylinder axis being substantially horizontal,

a piston slidably supported in said cylinder,

resilient means urging said piston toward the open end of said cylinder,

21 foot lever pivotally supported by said housing,

means on said foot lever engaging said piston for urging said piston toward the other end of said piston,

said housing including an inlet passage from said reservoir to said other cylinder end and including a check valve permitting liquid to flow to, but not from, said cylinder,

said housing including an outlet passage from said other cylinder end including a check valve permitting liquid to flow from, but not to, said cylinder,

said housing including a return passage communicating with said reservoir,

a flexible diaphragm extending across said housing near the top thereof dividing the interior of said housing into a liquid chamber and an air chamber, and

said housing including an air vent'from said air chamber to atmosphere.

References Cited by the Examiner UNITED STATES PATENTS 974,988 11/ 1910 Northam 10341 1,809,814 6/1931 Schutt 103-41 2,781,166 2/1957 Flood et al. 230-218 2,873,688 2/ 1959 Elder 103223 3,076,314 2/1963 Stromberg 230-218 3,199,458 8/1965 Hoehn 103-42 DONLEY J. STOCKING, Primary Examiner.

MARK NEWMAN, Examiner. W. J. KRAUSS, Assistant Examiner.

Claims

1. A FOOT ACTUATED PUMP COMPRISING: A HOUSING INCLUDING A RESERVOIR, A CYLINDER IN SAID HOUSING HAVING ONE END OPEN TO ATMOSPHERE, THE CYLINDER HAVING A GENERALLY HORIZONTAL AXIS, A PISTON SLIDABLE IN SAID CYLINDER AND INCLUDING MEANS PROJECTING FROM SAID OPEN END, A FOOT LEVER PIVOTALLY CONNECTED TO SAID HOUSING ON A GENERALLY HORIZONTAL AXIS ABOVE SAID CYLINDER AND IN A PLANE NORMAL TO THE AXIS OF THE CYLINDER, ROLLER MEANS ON SAID FOOT LEVER BENEATH SAID PIVOT AXIS AND PARALLEL THERETO ENGAGING THE PROJECTING END OF SAID PISTON AND OPERABLE TO MOVE SAID PISTON TOWARD THE OTHER END OF SAID CYLINDER UPON PIVOTAL MOVEMENT OF SAID FOOT LEVER, COOPERABLE MEANS ON SAID LEVER AND ON SAID HOUSING LIMITING PIVOTAL MOVEMENT OF SAID FOOT LEVER IN A DIRECTION TO LIMIT OUTWARD MOVEMENT OF SAID PISTON, RESILIENT MEANS NORMALLY URGING SAID PISTON AGAINST SAID MEANS ON SAID FOOT LEVER, SAID HOUSING HAVING AN OUTLET PASSAGE FROM SAID OTHER END OF SAID CYLINDER, AND SAID HOUSING INCLUDING AN INLET PASSAGE FROM SAID RESERVOIR TO SAID OTHER END OF SAID CYLINDER AND INCLUDING A CHECK VALVE PERMITTING A FLOW OF LIQUID TO, BUT NOT FROM, SAID CYLINDER, AND SAID HOUSING INCLUDING A SEPARATE RETURN PASSAGE COMMUNICATING WITH SAID RESERVOIR, SAID HOUSING INCLUDING A DIAPHRAGM EXTENDING ACROSS SAID HOUSING DIVIDING THE INTERIOR OF THE HOUSING INTO A LIQUID CHAMBER AND AN AIR CHAMBER, SAID HOUSING INCLUDING A VENT OPENING CONNECTING SAID AIR CHAMBER WITH ATMOSPHERE.