Patent Document

FIELD OF INVENTION 
       [0001]    The invention generally relates to a device and method for extracting a fluid sample from a reservoir that is relatively difficult to reach. More particularly, the present invention relates to a device and method for extracting a sample of motor oil from an engine. 
       BACKGROUND OF THE INVENTION 
       [0002]    It is well known in the motor vehicle arts that the rate of mechanical wear on the engine depends in part on the lubricating ability of the oil that is used to lubricate the engine parts, (sometimes referred to as “engine oil” or “motor oil”). The lubricating ability of these oils degrades as the engine is operated over time. In order to prevent catastrophic failures, there are various tests and guidelines for determining when an engine oil should be changed. Because of the range of conditions under which an engine may be operated, however, it is more reliable to test the oil in question than to rely solely on guidelines to determine when an oil should be changed. 
         [0003]    The quality of an oil sample taken from the engine indicates whether the oil has degraded beyond suitability for continued use. Various methods for assessing the quality of an oil sample have been standardized and are known. It is common to obtain an oil sample from the oil pan of the engine after the engine has been running, so that the assessment is performed on a sample that is representative of the overall oil quality. Because the oil pan is beneath the engine block, however, it is not readily accessed. 
         [0004]    Currently, oil samples are obtained using a variety of techniques and devices. Some devices obtain fluid through the drain opening. These devices rely on gravity flow, but require access to the underside of the engine, which is relatively difficult. 
         [0005]    Other devices obtain fluid through the dipstick tube, which does not require access to the underside of the engine. Because they cannot rely on gravity flow, however, these devices require means for drawing the oil up out of the oil reservoir. This may take the form of a reversible plunger mechanism, such as in the device shown in  FIG. 1 . In the device shown in  FIG. 1 , a rigid plunger is manually retracted using a finger loop, which in turn draws oil into an opening at the remote end of an oil sampling tube, as indicated by the arrows. When the desired amount of oil has been withdrawn, it is released into a sample collector (not shown) by using a spring-loaded ratchet mechanism to return the plunger to its original position. Because the sampling tube must fit within the dipstick opening, its inside diameter is relatively small. This means that, depending on the required sample size, the distance through which the plunger must be withdrawn can be relatively great. 
         [0006]    Because of shortcomings with the afore-mentioned device, the available technology for obtaining an oil sample remains less than satisfactory. In some devices, such a those that use spring-loaded suction for withdrawing oil from the oil plan, the oil discharge mechanism may leave some oil clinging to the inside of the sample tube. This can contaminate the subsequent sample, resulting in a false reading or analysis. In addition, the combined length of the plunger, handle, and sample tube can be well over four feet, making the device difficult to handle. Still further, the plunger, when it has been retracted, is susceptible to buckling when force is applied to return it to its starting position. Thus, there is a need for a sampling device that avoids cross-contamination of samples and is compact and easy to use. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides a device for retrieving a sample of oil from an engine. The device avoids cross-contamination of successive samples and is compact and easy to use. In some embodiments, the present device comprises a chamber having an inside wall and at least one oil inlet, a piston head slidably received in the chamber, a handle affixed to the chamber, and a piston member extending between the handle and the piston head, the piston member comprising a flexible member having a proximal end and a distal end, the distal end being affixed to the piston head. 
         [0008]    In preferred embodiments, the chamber comprises a length of flexible tubing. In some embodiments, the tubing is preferably semi-rigid tubing such as PFA and FEP or other materials that are chemically inert and can be used at high operation temperatures without deforming. In addition, PFA, FEP and other fluorated plastics provide the desirable self-lubrication properties. The handle may include a thumbwheel that engages the piston member such that rotation of the thumbwheel advances or retracts the piston-advancing mechanism. In some embodiments, the piston member includes at least one engagement device and in certain embodiments may comprise a length of beaded cable tie. 
         [0009]    The piston is preferably configured so as to move between an empty position in which said piston is at said oil inlet and a full position in which said piston is retracted from said oil inlet by a desired amount. 
         [0010]    Any engines use lubricant oil to maintain their sustained operation for long time. The engines can be powered by gasoline, diesel, electric current, hydraulic, pneumatic or stream. In addition to motor oil, the present device also can be used to extract fluid samples from other places that are relatively difficult to access. The compact storage size of the present invention is another advantage over previous devices. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0011]    Advantages of the present invention will become apparent to those skilled in the art with the benefit of the following detailed description of embodiments and upon reference to the accompanying drawings, in which: 
           [0012]      FIG. 1  is a diagram of a known oil extraction device; 
           [0013]      FIG. 2  is a diagram of a device constructed in accordance with a first embodiment of the invention; 
           [0014]      FIG. 3  is an enlarged cross-section of one portion of the embodiment of  FIG. 2 ; and 
           [0015]      FIG. 4  is a top view of the handle of the embodiment of  FIG. 2 ; 
           [0016]      FIG. 5  is a side view of an alternative embodiment of the invention; and 
           [0017]      FIG. 6  is an illustration showing the embodiment of  FIG. 2  in use. 
       
    
    
       [0018]    While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present invention as defined by the appended claims. 
       DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    Referring now to  FIGS. 2 and 3 , an oil extractor  10  constructed in accordance with a first embodiment of the invention includes a chamber  12  having a proximal end  14  and a distal end  16 , a handle  18  affixed to the proximal end of chamber  12 , and a piston member  20  slidably disposed within chamber  12 . Chamber  12  includes an oil inlet  13 . In certain embodiments, chamber  12  comprises a length of flexible tubing  11 , and in particular embodiments may be constructed of a flexible, heat-resistant, transparent or translucent plastic. 
         [0020]    Chamber  12  may be attached to handle  18  by any suitable means, such as a mounting clip  15 . Mounting clip  15  may comprise a body  19  having a bore  17  ( FIG. 4 ) therethrough. Proximal end  14  of chamber  12  may be disposed in bore  17  and affixed thereto, such as by adhesive or other means. Alternatively, proximal end  14  may be affixed to the outside of body  19 , or directly to handle  18 , if desired. 
         [0021]    Piston member  20  is slidably disposed in chamber  12 . Like chamber  12 , piston member  20  has a proximal end  24  and a distal end  26  ( FIG. 3 ). Distal end  26  includes a piston head  28  that is preferably sized to fit sealingly within chamber  12 . Specifically, piston head  28  preferably fits sufficiently snugly that a fluid seal is formed between piston head  28  and the inside wall of chamber  12 . In some embodiments, piston head  28  may be formed from or integrally with piston member  20 . In alternative embodiments, piston head  28  may be formed separately and affixed to piston member  20 . 
         [0022]    Piston member  20  is preferably of sufficient length that proximal end  24  thereof extends some distance beyond the proximal end of chamber  12 . Thus, piston head  28  can be advanced and retracted within chamber  12  by advancing or retracting the proximal end  24  of piston member  20 . In some embodiments proximal end  24  of piston member  20  may be received in handle  18  and may optionally be spooled, coiled, or otherwise stored therein. By way of example only, proximal end  24  may be spooled on a spool  50 , as shown in phantom in  FIG. 5 . Tracks, guides, chambers and other suitable means for storing end  24  may also be used, if desired. In alternative embodiments, piston member  20  may not comprise a single continuous length of material and may instead comprise an assembly of members connected together so as to function as a piston member. 
         [0023]    In order to facilitate movement of piston member  20 , proximal end  24  of piston member  20  is, in some embodiments, provided with an engagement device  30 . Engagement device  30  may take any of a variety of forms, but is preferably a feature that facilitates manual movement of piston member  20 . In preferred embodiments, engagement device facilitates one-handed movement of piston member  20 . Thus, in certain embodiments, engagement device  30  may comprise one or more bosses, grooves, ridges, bumps, bulges, or the like. In particular, the engagement devices or beads can be octagonal or any other shape that can engage the thumbwheel and any corresponding shape therein, if present. Rounded bead shapes are preferred for easier manufacturing and operation by users. 
         [0024]    In the embodiment shown in  FIGS. 2-4  and  6 , piston member  20  comprises a length of beaded cable tie, with the result that the sequential beads along its length can function as engagement devices. In addition, the beads in this embodiment help to keep piston member centered within chamber  12 . 
         [0025]    To further facilitate movement of piston member  20 , some embodiments of the present device are provided with a thumbwheel  40  rotatably mounted in or on handle  18 , as shown at  40  in  FIGS. 2 and 4 . Referring particularly to  FIG. 4 , in certain embodiments, thumbwheel  40  is mounted on an axle  47  within handle  18  and extends partially out of handle  18  through an opening  21 . Thumbwheel  40  is preferably positioned such that its perimeter  42  is parallel to the general direction of piston member  20  where it is exits from chamber  12 . In other embodiments, thumbwheel  40  may have a diameter that is greater than the depth of handle  18  and may be positioned such that it extends out of handle  18  through openings in both the top and bottom surfaces of handle  18 , as shown at  27  in  FIG. 5 . 
         [0026]    To facilitate engagement of piston member  20 , edge  42  preferably includes a circumferential groove  44 . An operator of the tool may, by capturing the proximal end  24  of piston member between his thumb and the edge of thumbwheel  40 , readily advance or retract piston member  20 , thereby advancing or retracting piston head  28  at the distal end of the tool. 
         [0027]    In embodiments in which piston member  20  includes one or more engagement devices, thumbwheel  40  may include one or more complementary devices. Thus, for example, if piston member  20  comprises cable tie material, groove  44  may include one or more depressions  46  that are sized and spaced to receive successive beads. Alternatively, engagement devices may be provided on thumbwheel  40  and receiving devices on piston member  20 , so that thumbwheel  40  engages piston member  20  in the manner of a gear engaging a chain. It will be understood that the nature and/or presence of engagement devices is not critical to the operability of the invention. 
         [0028]    Referring now to  FIG. 6 , when it is desired to remove a sample of oil from an oil reservoir, such as may occur in the course of routine engine maintenance tests, the present device is configured such that piston head  28  is at or near the oil inlet  13  of chamber  12 . If piston head  28  is not positioned at or near inlet  13 , operation of the tool will be sub-optimal. For example, if piston head  28  extends beyond inlet  13 , fluid will enter chamber  12  behind piston head  28 . Fluid behind piston head  28  may remain in the tool indefinitely or may be dispensed with one or more subsequent samples, causing contamination. 
         [0029]    Chamber  12  is then positioned such that its oil inlet  13  is submerged in the oil that is to be sampled. Piston member  20  extends from piston head  28 , through the length of chamber  20  and from the proximal end of chamber  20  toward handle  18 . By aligning the proximal end of piston member  20  with thumbwheel  40  and moving his thumb, or thumb and fore-finger in the embodiment shown in  FIG. 5 , as shown at arrow  45   a,  thereby rotating thumbwheel  40  as shown by arrow  45   b,  the operator can retract piston member  20  as shown at arrow  45   c,  thereby pulling piston head  28  into chamber  12  and drawing an oil sample into chamber  20  via inlet  13 . 
         [0030]    It may be preferred in some embodiments to provide a means for ensuring that the oil sample has a predetermined volume. This may be accomplished by providing one or marks, such as on piston member  20  and/or handle  18  and/or thumbwheel  40 , or elsewhere. The position(s) of such mark(s) can be set and/or annotated so as to indicate when piston head  28  has been retracted sufficiently to have withdrawn a desired sample size. An exemplary sample size may be 2 ml. Alternatively, chamber  12  may be such that it is possible to view piston head  28  through the chamber wall, so that a visible determination of the position of piston head  28  may be made. Still further, a stop means may be provided, such as within chamber  12 , on handle  18 , on clip  15 , or elsewhere. The stop means, if present, may prevent piston head  28  from being retracted beyond a desired point thereby preventing the withdrawal of overlarge samples. For example, a heat shrinkable collar may be added to a beaded piston member at the point where it is desired to position the stop means, so as to prevent the piston member from traveling further. 
         [0031]    When it is desired to discharge the oil sample, such as into a testing device (not shown), the operator reverses the process and advances piston member  20  into chamber  12 . Because piston head  28  preferably forms a fluid seal with the inside of chamber  12 , substantially all of the oil within chamber  12  will be discharged if piston head  28  is extended all the way to oil inlet  13 . If piston head  28  is not extended all the way to inlet  13 , some fluid may remain in the chamber and may thus contaminate subsequent samples. It is therefore preferred in some embodiments to provide a means for ensuring complete dispensing of each sample. This may take the form of one or marks, such as on piston member  20  and/or handle  18  and/or thumbwheel  40 , or elsewhere. The position(s) of such mark(s) can be set and/or annotated so as to indicate when piston head  28  is at inlet  13 . 
         [0032]    Alternatively, chamber  12  may be such that it is possible to view piston head  28  through the chamber wall, so that a visible determination of the position of piston head  28  may be made. Still further, a stop means may be provided, such as at inlet  13 , on handle  18 , on clip  15 , or elsewhere. The stop means, if present, may both prevent piston head  28  from exiting through inlet  13  and also be used to ensure complete dispensing of the fluid sample. 
         [0033]    Because the present device comprises a flexible tube and a compact handle, it is much less cumbersome and therefore easier to carry and handle than previous devices. Because substantially all of each sample is discharged, successive samples are not contaminated and it is not necessary to clean the device between samples. The present device can be operated easily and repeatedly, without risk of damage to the device. In addition, the present device makes it possible to retrieve fluid samples from fluidic samples from reservoirs that are difficult to access, such as industrial rotational equipment. 
         [0034]    Further modifications and alternative embodiments of various aspects of the invention may be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. For example, the present device may be used to sample fluids other than oil, and from environments other than an engine. 
         [0035]    It is to be understood that the forms of the invention shown and described herein may be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description to the invention. Changes may be made in the elements described herein without departing from the scope of the invention as described in the following claims. In addition, it is to be understood that features described herein independently may, in certain embodiments, be combined.

Technology Category: 7