Patent Application
20080145250
1) Field of the Invention
The present application relates to the fluid pumping arts and, more particularly, to a hand pump for manually pumping fluids from a reservoir. The preferred embodiment will be described in connection with a manual pump gun used in combination with a utility oiler for dispensing lubricating fluids onto workpieces during machining operations such as tapping and threading pipes and the like. It is to be appreciated, however, that the preferred embodiments are applicable in a wide range of applications beyond use with industrial lubricants such as in chemical processing applications, food service applications and anywhere there is a need to manually transfer fluids by pumping from a reservoir into a desired area.
2) Description of the Related Art
Many metal working procedures require some form of lubricating fluid delivered to the workpiece and/or to the tool by a pump or the like from an auxiliary source. Examples include hand threading applications where a tool such as a cutting die is rotated around a stationary pipe, usually using a ratcheting head holding the tool. Other examples include automated and semi-automated threading operations wherein power driven threading equipment rotates a tubular workpiece such as a pipe or the like relative to one or more die heads mounted on the threading equipment and carrying one or more cutters or reamers for removing metal from the workpiece as it rotates relative to the tooling. It is important of course to provide a sufficient amount of cooling and/or lubricating fluids to help prevent damage to the tooling resulting in high quality and accurate threads or other patterns imparted onto the workpiece. It is also important to wash the work area free from chips, filings, and the like by providing a fluid which can be selectively delivered under a modest pressure.
Portable oil dispensers have been provided heretofore for use with pipe threading apparatus, for example. One such oil dispenser has been available from The Ridge Tool Company of Elyria, Ohio under the latter's product designation no. 418 Oiler, comprising a bucket for providing a reservoir for thread cutting oil, a drip pan removably mounted on the bucket for receiving chips and oil from the thread cutting apparatus and separating the oil for return to the reservoir in the bucket, and a hand-held trigger operated pump connected to the bucket by a flexible hose and operable by a threading machine operator to dispense oil onto a workpiece being threaded. The bucket typically includes a bulkhead fitting for connecting a reservoir area of the bucket in flow communication with a manually operated pump and, preferably, a strainer for straining oil during pumping thereof from the reservoir area in order to prevent chips of metal or other materials from entering into the manual pump.
a and 2b illustrate cross-sectional views of the pump 10 of
With continued reference to those figures, the prior art pumps of the type described typically include first and second one-way check valve devices 32 and 38 operable in a manner well known in the art to draw lubricating fluid from the associated reservoir (not shown) through the flexible hose 20, into the fluid passageway 26 and ejected onto the workpiece through the dispensing nozzle 14. In the prior art pump 10 illustrated, the check valve assemblies 32, 38 include a steel check ball 34, 40, respectively biased against suitable check ball seats 36, 42 formed on the distal end of the piston member 28 and on a side of the threaded coupling element 22 opposite from the flexible hose 20.
One disadvantage of the prior art pump 10 illustrated in the figures is a modest degree of vulnerability to decrease the efficiency through the passage of metal chips and other particles from the reservoir and into the fluid passageway 26. The metal particles have, at times, become lodged between the steel check balls 34, 40 and their respective seats 36, 42 thus preventing a complete and efficient fluid seal therebetween.
It is to be observed that the upper end of the fluid passageway 26 adjacent the piston member 28 and in the region of the spring member 30 is rather large as compared against the remainder of the passageway. This has, at times, lead to some difficulty in priming the pump during initial use and in reducing the ability of the pump to pull lubricating fluids up through the hose 20 to a specified height which is convenient to the user.
More particularly, the pump 10 of the prior art may become partially or fully filled with gas such as air when the device is opened during such operations such as cleaning or disassembling the unit. Under these conditions, the ability of the pump to pull oil up through the hose to a specified height is significantly different from that of a pump which is fully filled with a liquid such as oil. As the piston member 28 of the pump is actuated between the positions illustrated in
It is therefore an object of the present application to provide a fluid pump of the type which is not easily susceptible to performance degradation due to particles or the like becoming lodged therein during normal use.
It is a further object of the present application to provide a fluid pump of the type which is easily primed regardless of whether it is first operated from a “dry” condition filled with air or other gasses.
It is yet a further object of the present application to provide a manually operated fluid dispenser of the type which can pull or otherwise draw fluid or other oils from an associated reservoir up to at least the shoulders or waist of a user during normal use thereof.
These and other objects and advantages of the fluid pump of the present application will become apparent to those skilled in the art upon a reading and understanding of the drawings and specification to follow below.
The fluid pump of the present application provides a unique manually operable oiler which overcomes the difficulties encountered in prior art oilers and provides improved performance over prior oilers during priming of the pump, during use of the pump elevated heights relative to the reservoir, and with regard to pump efficiency while pumping fluids having metal particles or other debris entrained therein.
In one form, a fluid pump is provided including a housing defining a cylinder and a chamber in fluid communication with the housing. The fluid pump includes a manually displaceable piston received in the cylinder. The piston has a distal end, a proximal end, and a fluid payout conduit extending between the distal end and the proximal end. The piston is slidable with the cylinder between first and second positions relative to the housing. A spring is provided in the chamber and is received therein between the housing and the proximal end of the piston. The spring biases the piston towards the first position. A first one-way check valve is disposed on the distal end of the piston and is in fluid communication with the fluid payout conduit defined through the piston. A second one-way check valve is disposed on the housing and is in fluid communication with the chamber. For purposes of enabling enhanced priming capabilities and suction capabilities, a fluid displacement member is provided for substantially completely filling the chamber when the piston is in the second position and for substantially completely emptying the chamber when the piston is in the first position. In that way, the volume difference in the passageway is defined by the housing as determined when the piston is at the first and second positions is substantially enhanced over prior art pumps.
In accordance with a further aspect of the present application, the fluid displacement member includes an annular member surrounding the spring. The annular member is preferably movable with the piston and, in one embodiment, is formed integrally with the piston.
In accordance with a further aspect of the present application, the fluid displacement member is a cylindrical spring disposed within the space defined by the spring biasing the piston towards the first position. Preferably, the cylindrical member is movable with the piston and, in one embodiment, is formed integrally with the piston.
In accordance with yet a further aspect of the present application, the fluid displacement member includes an annular member surrounding the spring together with a cylindrical member disposed within the inner cylindrical hollow spaced defined by the spring biasing the piston towards the first position. Preferably, the annular member and cylindrical member are movable with the piston and, in one embodiment, are formed integrally with the piston.
In accordance with yet a further aspect of the present application, the cylinder defined by the housing includes a rough cylinder surface adapted to receive a plastic piston therein. The plastic piston carries an elastic o-ring having a low durometer.
Yet still further in accordance with another aspect of the present application, each of the one-way check valves includes a rubber ball member and a circular seat. The rubber ball member has a low durometer and is adapted to permit metal chips and other materials which might become entrained in the fluid to be received in the body of the ball thus permitting the ball to substantially seal around the seat portion of the check valve.
These and other advantages and objectives of the present application will become apparent to those of ordinary skill in the art.
a and 2b are cross-sectional views of a manual pump of the prior art oiler shown in
a and 5b are perspective and cross-sectional views, respectively, of a piston member received in the fluid pump shown in
a is a cross-sectional view of a threaded fitting member with an integrated ball seat and a lead-in taper adjacent the ball seat in accordance with the prior art; and,
b is a cross-sectional view of a threaded fitting member with an integrated ball seat and lead-in taper adjacent the ball seat in accordance with a preferred embodiment of the application.
Referring now to the drawings wherein purposes are for illustrating the preferred embodiments only and not for purposes of limiting same, the subject pump 50 is shown in cross section in
A central region 58 of the main body member 52 defines an internal passageway adapted to receive the piston member of
A spout 64 extends through a suitably arranged opening formed in the trigger member 60 substantially as shown. The spout 64 preferably defines a fluid conducting conduit or channel for permitting oil or the like pumped from the main body member 52 to flow onto an associated workpiece through an open tip 66 located at the distal end 68 of the spout. The opposite end of the spout 64 includes a fluid connector member 70 for threaded engagement onto a piston member 120 slidably received within a cylinder defined by the main body portion 52 and operable in a manner to be described in greater detail below. As shown, the fluid connector member 70 has a radiused convex shoulder surface 72 adapted to provide a smooth curved engagement region for contact with a plastic wear adapter 72a carried on the trigger member 60 as shown. The wear adapter 72a can be formed on or by the trigger member as desired.
With still further continued reference to
A first one-way check valve assembly 90 is provided at the distal end of the piston member 120 as shown. In its preferred form, the first one-way check valve assembly 90 includes a biasing spring member 92 for urging a rubber check ball 94 into selective engagement with a seat portion 130 (
A second one-way check valve assembly 100 is disposed at the lower end of the handle portion 56 and in fluid communication with the vertical or handle passageway 84. Similar to the first check valve assembly, the second one-way check valve assembly 100 includes a spring member 102 provided for urging a rubber check ball 104 into engagement with a angled seat 74a of a threaded coupling element 76 provided for attachment of the subject pump 50 to an associated flexible hose (not shown) or other fluid conduit.
In accordance with the present application, each of the check balls 94, 104 are preferably formed of a rubber material having a compliant characteristic whereby the check balls 94, 104 are adapted to conform around metal particles or other debris passing through the subject pump thereby enabling each of the check balls 94, 104 to adequately operate through contact with their respective seat portions 130, in the piston 120 and 74 in the threading coupling element 76. In that way, a proper seal can be established between the check balls and their respective circular sealing surfaces regardless of whether debris or the like becomes located between the ball and the sealing surface. Essentially, check balls conform to the metal particles, chips, or other debris so that the debris or other pieces do not adversely affect the sealing capability of the valve assemblies.
In addition to the above, it has been found that the second one-way check valve assembly 100 works best with a check ball 104 having a shore hardness within a range of about 60 D to 70 D but preferably of about 65 D operative with an angled spherical seat 74a in the threaded coupling member 76. Further, as illustrated, a lead-in portion 74 is disposed adjacent the ball seat 74a in the coupling member 76 for purposes of selectively contacting the check ball 104 during operation of the subject pump gun 50 to encourage the ball to locate properly relative to the ball seat during use in order to form a good fluid seal between the check ball 104 and the ball seat 74a.
The lead-in portion 74 provides enhanced performance characteristics. More particularly, as shown in
With continued reference to
Further, at the proximal end 128 of the piston member, an outer skirt member 140 is formed as shown in a spaced apart relation relative to an inner member 142. A gap 144 is thereby defined between the outer skirt member 140 and the inner member 142. As best shown in
The preferred form of the subject piston member 120 enables smoother operation, enhanced resistance to wear, and simplified manufacturing. In the prior art, sticking or slow piston motion often occurred because of metal particles contained within the oil becoming lodged between the piston and the piston bore causing the piston to stick or to move with substantial friction. In typical prior art pistons in oiler guns of the type described above, clearances are held as tightly as the manufacturing process permits thus inviting the sticking or slow moving piston problem. However, in accordance with the present application, the amount of sticking piston motion and slow piston motion is reduced by increasing the clearance between the piston and the piston bore. As noted above, the piston 120 is provided with a plurality of guide rib members 136 defining annular surfaces that create an effective outer piston diameter that contact the inner surface of the bore 80. The annular guide rib members 136 also provide for overall enhanced moldability of the piston 120. The preferred piston member 120 shown in
In its preferred form, the outer skirt member 140 takes on the shape of an annular member substantially surrounding the biasing spring 110. Further, the inner member 142 is in the form of a cylindrical member disposed within the inner cylindrical hollow area 112 defined by the biasing spring 110. The spring size together with the gap size is particularly selected so that the biasing spring 110 freely floats within the gap 144 but with very little free play.
It is to be appreciated with reference once again to
As noted above with regard to prior art pump guns, gas such as bubbles or the like entrained in the working fluid adversely affects the efficiency of the gun. More particularly, gas is compressible and as understood by those skilled in the art, any gas which might accumulate in the gun will adversely affect pumping efficiency and, in particular, adversely affect the priming capability and priming height of the gun. In the pump 50 in accordance with the subject application, the volume of gas in the chamber is reduced to an optimized minimum by providing the fluid displacement member 150 movable together with the piston member 120 to nearly eliminate any volume within the piston itself that is not compressed. As shown above, preferably, the fluid displacement member 150 is formed integrally with the piston member 120. However, other forms of fluid displacement member can be used as well.
In addition to the above, as shown in the drawing figures, the sealing member 132 is carried in a groove 134 moved to the extreme proximal end 128 of the piston member 120 in order to reduce the volume within the piston itself that is not compressed.
Lastly, it is to be appreciated that preferably, the gap 144 formed between the outer skirt member 140 and the inner guide member 142 is minimized to bring the skirt and guide members 140, 142 as close as possible to engagement with the spring member 92 to maximize the volume displaced by the fluid displacement member 150 formed by the skirt and guide members.
With continued reference to drawing
Further in connection with the relationship between the piston member 120 and the cylinder 80, in its preferred form, the cylinder has a smoothed surface to enable the sealing member 132 to be easily manually actuated therein. A burnishing process can be used to smooth out roughness from machining which would normally cause the o-ring seal 132 to drag. This drag tends to inhibit the return of the piston when letting go of the trigger 60. In its preferred form, the sealing member 132 is a low durometer o-ring such as, for example, 55 durometer.
The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
