Hand pump oiler

BACKGROUND OF THE INVENTION

This invention relates to an improved hand pump oiler ²⁵and, in particular, to a hand pump oiler having fewer parts than previously available hand pump oilers.

Conventional hand pump oilers which are commercially available all have, to our knowledge, a similar design. An oil can is provided which contains the oil. A spout leads ³⁰from the interior of the can and a hand lever is provided to pump the oil by means of a pump mechanism through the spout. The pump mechanism generally includes a pair of check valves which insure that during one direction of the lever pull action on the oiler, oil enclosed within a 35 chamber defined by a piston and cylinder pump will be driven through the spout and will not leak back into the can. Generally, the hand pump oilers, known to us, are fabricated by die cast metal parts or stamped metal parts.

Thus, an oiler which eliminates any number of parts or 40 changes the manner in which the parts are manufactured or combined will provide an improved hand pump oiler. On the other hand, any improved hand pump oiler must have the same function as conventional oilers. Namely, at least the same amount and volume of oil must be 45 pumped at the same pressure. Also, the pump lever must return to its original position, and the oiler must prime itself automatically. Finally, the oiler must be self-sealing and must not leak oil through the pump mechanism.

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BRIEF SUMMARY OF THE INVENTION

In a principal aspect, this invention comprises an improved hand pump oiler of the type which includes an oil can, a spout and a pump mechanism for pumping the oil from the oiler. The improvement resides in the pump 55 mechanism which includes a piston attached to the spout and a cylinder slidable over the piston. The cylinder and piston thus enclose a volume of oil. A single check valve is included in the cylinder, and an integral piston valve is provided between the cylinder and piston. A strap spring 60 insures reutrn of the hand pump lever to its original position following a pumping stroke.

It is thus an object of the present invention to provide an improved hand pump oiler.

It is a further object of the present invention to provide 65 an improved hand pump oiler having fewer parts than conventional oilers.

One further object of the present invention is to provide a hand pump oiler which includes parts simplified in construction in comparison with prior art hand pump oilers, 70

Still another object of the present invention is to provide an improved hand pump oiler which is self-priming, and which pumps the same or more oil at the same pressure as prior art oilers.

These and other objects, advantages and features of the present invention will be set forth in greater detail in the description which follows.

BRIEF DESCRIPTION OF THE DRAWING

In the detailed description which follows, reference will be made to the drawing comprised in the following figures:

FIG. 1 is a cut-away, perspective view of the improved hand pump oiler of the present invention;

FIG. 2 is an elevational, cross-sectional view of the improved hand pump oiler of the invention taken substantially along the line 2—2 shown in FIG. 1, the pumping cylinder being in a fully extended position and the hand lever being in the unoperated or rest position;

FIG. 3 is also an elevational, cross-sectional view of the hand pump oiler shown in FIG. 2, with the relative position of the parts comprising the pump mechanism altered due to partial movement of the hand lever;

FIG. 4 is still another elevational, cross-sectional view of the oiler with the pumping cylinder positioned in a maximum stroke position; and

FIG. 5 shows the oiler upon release of the hand lever with the pumping cylinder returning to its normal rest position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

To appreciate the present invention, one must first understand the operation of prior art or conventional design hand pump oilers. In a prior art oiler, the lever or trigger handle on the outside of the pump can is generally attached to a plunger pin. The plunger pin is connected with a pump mechanism in the can including a cylinder which is adapted to slide over a piston. A spiral spring is positioned along the plunger pin in order to keep the trigger or lever under constant bias and thus keep the cylinder in its extended position. A piston valve ball and piston valve spring provide a check valve in the head of the piston of the conventional design hand pump oiler. Similarly, an inlet valve ball and inlet valve spring provide a check valve to the chamber defined between the piston and the interior of the cylinder. Conventional designs utilize either die cast or stamped metal parts. Thus, in a conventional oiler, there are at least nine metal parts which comprise the mechanism enabling one to pump the oil from the oil can.

Referring now to the figures, the improved hand pump oiler of the present- invention is illustrated in FIG. 1 in a perspective view. In FIGS. 2 through 5, the detailed construction and pump cycle of the improved hand pump oiler of the present invention is illustrated. As will be apparent from the detailed description which follows, FIG. 2 shows the hand pump oiler in its normal position prior to an oil discharge stroke of the hand pump lever. FIG. 3 shows the oiler after the lever or trigger of the oiler has been moved. FIG. 4 shows further movement of the lever or trigger of the oiler and FIG. 5 shows the lever returning to its normal position.

Referring to FIG. 1, the hand pump oiler includes an oil can 10 into which a fluid, typically oil, is provided. A spout 12 leads from inside can 10 and through the screw top 14. Top 14 is threaded onto the mouth of the can 10 and cooperates with a seal 15 to provide a substantially air-tight seal of top 14 and can 10. A pump mechanism is attached to the top 14 and includes a trigger or hand lever 16 connected with a plunger pin 18 and a pump cylinder assembly attached to interior end 28 of spout 12 inside the can 10. That is, end 28 terminates at a piston 22 which cooperates with a cylinder 20. A biasing

3,664,556 strap spring 24 maintains the trigger 16 and cylinder 20 in their normal position.

Referring now to FIG. 2, the improved hand pump oiler of the present invention described above in relation to FIG. 1 is now described in greater detail. The spout 12 is preferably a length of metal tubing having an approximate 90° bend at its midpoint. Spout 12 terminates at its outer end with a suitable nozzle 26. The internal diameter of the spout 12 is sufficient to permit fluid of the viscosity being pumped to pass through the spout 12 without difficulty. The spout 12 includes an interior end 28 which extends downwardly into the oil can 10 and is fastened to the piston 22. The piston 22 includes a piston head 30 and a piston wall 32. The internal passage of the spout 12 defines the fluid flow path connecting with a center line passage 34 in the piston 22. The center line passage 34, in turn, connects with a radial piston passage 36 through wall 32 near the head 30 of the piston 22.

The trigger or hand lever 16 includes a hand grip portion 38, a pivot point 40 which engages the outer extension of the spout 12, and a plunger pin end 42 adapted to cooperate with the plunger pin 18. The plunger pin 18 is comprised of a single rod which fits through an opening in the plunger pin end 42 of the trigger 16 and then through an opening in the screw cap 14. A washer 44 is provided to prevent wear and to seal the plunger pin 18 through the screw cap 14. The strap spring 24 includes openings at its opposite ends through which the plunger pin 18 fits. The lower end of the plunger pin 18 is fixed rigidly to the cylinder 20 by means of a lug 46. Thus, the spring 24 flexes or expands between the cap 14 and the lug 46, the amount of flexure depending upon the amount that the trigger 16 has been depressed.

The construction of the cylinder 20 is highly unique. Cylinder 20 includes a channel or valve passage 47 on an interior wall 48. The channel 47 is situated to cooperate with radial passage 36 as more fully described below. A valve port opening 50 is provided at the lower end of the cylinder 20. A floating, one-piece inlet valve 52 is provided for the valve port opening 50. As will be noted, the inlet valve 52 includes an upper disc-shaped portion 54 which seats on the interior of the cylinder 20. The inlet valve 52 also includes a lower gripping portion 56 which prevents the inlet valve 52 from floating into the chamber 58 defined by the piston 22 and the cylinder 20.

Referring now to FIGS. 2 through 5 in sequence, a brief description of the operation of the hand pump oiler will be provided. In FIG. 2, the oiler is in its rest position. Assuming that the oiler is filled with a fluid, such as oil, the oil will fill the volume of chamber 58. Because the inlet valve 52 is really floating, the chamber 58 becomes primed merely by inserting the pump mechanism into the filled oil can. At this stage, the strap spring 24 is extended to its fullest length.

Now referring to FIG. 3, the trigger 16 is pulled so that it pivots about pivot point 40. This causes plunger pin 18 to be pulled through the screw cap 14 against the biasing force of spring 24. Simultaneously, the cylinder 20 is pulled upward over the surface or wall 32 of the piston 22. The oil or fluid trapped in the chamber 58 then passes by means of channel 47 into radial passage 36 and out center line passage 34 and ultimated through the nozzle 26. During such a pump stroke, the inlet valve 52 is seated against the interior of the cylinder 20 so that fluid within the chamber 58 does not leak back into the oil can.

Very importantly, during the rest position illustrated in FIG. 2, the channel 47 is not connected to the radial passage 36. However, when the lever 16 is depressed as in FIG. 3, the channel 47 connects with the radial passage 36. Thus, whenever the lever 16 is depressed so that the volume within the chamber 58 is less than the maximum volume of chamber 58, a passageway is provided for fluid flow passage through the channel 47 and piston 22. The cylinder 20 and piston 22 along with the associated channel 47 and passage 36 thus function as an integral piston valve through which oil passes only when the volume of chamber 58 is less than the maximum volume of the chamber 58.

There are no moving parts for the integral piston valve. The valve is thus automatic and not pressure actuated. Valve action is a function of the relative position of the piston and the cylinder. The passageway or channel 47 and passage 36 provide for free flow of the fluid. No restriction is provided due to a spring force as in prior art pumps. Thus, foreign objects can pass through the pump and out of the spout 12 without fouling up the pump mechanism.

FIG. 4 shows that the trigger 16 is fully depressed with the cylinder 20 at its most upright or maximum stroke position. It can be seen that channel 47 extends parallel to the direction of cylinder 20 travel. As illustrated in FIG. 4, channel 47 extends partially along the interior wall of cylinder 20 and terminates at a position to seal fluid flow through spout 12 whenever the cylinder is in the maximum stroke position. Because of this limitation of the dimensions of channel 47, fluid cannot leak from the oiler regardless of the attitude of the oiler. Thus, fluid is sealed in the oiler at the rest position and at the maximum stroke position. In FIG. 5 the trigger has been released and is now being driven to its normal rest position shown in FIG. 2 by action of the strap spring 24. The strap spring 24 provides a relatively constant spring rate regardless of its extension. This is in contrast to conventional coil compression springs which provide propressively more resistance as the spring is compressed. Thus, the present improved hand pump oiler provides uniform trigger “pull.” In addition, a uniform return force is applied to the cylinder 20, allowing closer sliding fit allowances between the piston 22 and cylinder 20. Utilization of a strap spring 24 means that material other than metals may be used for a spring. This is an important consideration when one desires to provide a nonmetal strap spring which will not deteriorate when used with corrosive liquids. The preferred material for the spring is nylon.

Referring now to FIG. 5, during the stage when the lever 16 is released, the valve 52 is caused to float upwardly and fluid is caused to flow in through the valve port 50 in the manner indicated by the arrows in FIG. 5. The valve 52 is quite distinct from those used in the prior art oilers, in that the prior art oilers utilized a spring and valve ball arrangement. However, there are numerous advantages to the present construction. For example, the valve 52 self-locks into place during assembly and cannot fall out or be rendered inoperable by accidental disassembly of the piston 22 from the cylinder 20, for example. The valve 52 is also a free-flowing valve 52 and does not restrict the flow into the cylinder 20. The action of the valve 52 is thus not a function of spring pressure. This is a decided advantage with high viscosity fluids. The valve 52 is also self-sealing. Increasing the internal pressure in chamber 58 during actuation of the cylinder 20 actually improves the valve seal. It is not dependent upon the mechanical spring pressure. The flexible construction of the valve 52, which is preferably made from a plastic material, permits serviceable operation of the valve even with foreign material in the area of the valve seat. The valve 52 will thus conform to minor irregularities. During the return action of the pump mechanism quicker response will be noted, since the valve 52 is not working against the spring and will open immediately at the start of the cylinder return stroke.

In comparison tests of the improved hand pump oiler of the present invention and a typical prior art oiler, the oilers were both driven for more than four million cycles. The improved hand pump oiler of the present invention showed numerous advantages. For example, the hand pump oiler of the present invention quickly primes itself, even after disassembly and inspection. Repriming

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ceased after two million cycles in the typical prior art oiler. The improved operation of the present invention is believed attributable to the unique construction and choice of materials. The plastic piston 22 and cylinder 20 wear better than prior art metal parts. In fact, it was observed that the plastic actually “grows” or “swells” by absorbing some of the oil, thus improving the seal between the pump parts. Moreover, any wear of the pump parts is compensated as the oiler is used and ages.