Abstract:
A flexible locking dipstick module useful with a motor vehicle including an oil reservoir. A dipstick is disposed within a housing which has one end thereof affixed to the oil reservoir and extends therefrom to a location within the engine compartment of a motor vehicle. The end of the module disposed within the engine compartment includes a quick disconnect locking coupling providing for ready installation and removal of the dipstick. The coupling further provides protection against blow out of the dipstick in the event of inordinate build up of pressure within the oil reservoir. Further, one portion of the outboard coupling may be employed as a liquid-tight closure for a dipstick entry opening in the oil reservoir during removal and/or storage of the engine.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation in part of copending U.S. patent application Ser. No. 11/955,887, filed Dec. 13, 2007, entitled LOCKING FLEXIBLE ENGINE DIPSTICK upon which priority is claimed and the entirety of which is incorporated herein reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of Invention 
         [0004]    This invention relates to motor vehicle parts and accessories and particularly to dipsticks useful in the engine lubricant (oil) reservoir (at times referred to as “oil pan” of the engine for a motor vehicle. 
         [0005]    2. Background 
         [0006]    In motor vehicles, dipsticks are employed for purposes of visual inspection of the quantity (and to a lesser degree of the quality) of fluid located within a closed reservoir in a motor vehicle. In general, oil reservoirs of motor vehicles commonly are provided with an opening leading from external of the oil reservoir into the interior of the reservoir. Often this opening is provided with a fitting, such as a hollow tube. An inboard end of the tube is mounted in the opening leading into the reservoir with the tube extending from the oil reservoir to a terminal location within the engine compartment of the vehicle where the outboard end of the tube is commonly anchored to an engine head or other structure within the engine compartment of the motor vehicle, remote from the oil reservoir. Thus, the open outboard end of the tube is readily accessible within the engine compartment of a motor vehicle. An elongated removable dipstick commonly is inserted into the outboard end of the tube and extends into the interior of the oil reservoir whereupon the hollow tube becomes a housing for the dipstick. Within the oil reservoir, the inboard end of the dipstick becomes immersed within the fluid disposed within the reservoir. The extent of insertion of the dipstick into the reservoir is limited to a constant value established commonly by some form of stop on the dipstick which engages the outboard end of the tube to limit that distance by which the dipstick may be inserted into the reservoir. Such extent of insertion distance is thus maintained constant over each and every time the dipstick is inserted into the reservoir. By this means, upon withdrawal of the dipstick from the reservoir, the level of fluid on that end of the dipstick which is inserted into the reservoir is indicative of the level (quantity) of fluid within the reservoir. Other than during the action of checking the level of fluid within the reservoir, the dipstick is stored within its tubular housing. The structure of the outboard end of the dipstick may include a structural element which is frictionally slidably received within the outboard end of the tubular housing and serves in part to seal off the open outboard end of housing. These devices are prone to leakage of lubricant fluid from the tubular housing and fail to ensure the retention of the dipstick within the housing under certain vehicle operating conditions. 
         [0007]    In certain motor vehicles, such as racing cars, the operation of the vehicle may build up inordinate pressure within the oil reservoir. Such pressure levels may be sufficient to “blow out” a prior art dipstick from its elongated tubular housing with obvious disastrous results which may include starting a fire within the engine compartment of the vehicle. Also, there exist the problems associated with oil leaking onto a race trace, resulting in slick tires, crashes and monetary penalties. 
         [0008]    Furthermore, a prior art oil reservoir dipstick can become freed from its housing, thereby allowing air to leak through the dipstick housing into the engine crankcase. Certain motor vehicles, such as racing cars of the type typically used in the drag racing industry, are equipped with vacuum systems configured to assist in evacuating the crankcase of the vehicle engine, thereby increasing the overall horsepower of the vehicle during operation. In such vehicles, air leakage into the crankcase interferes with the vacuum system, thereby resulting in decreased horsepower of the vehicle. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    The present invention comprises a flexible locking dipstick module useful with a motor vehicle including an oil reservoir. The dipstick is disposed within a housing which has one end thereof affixed to the oil reservoir and extends therefrom to a location within the engine compartment of the motor vehicle. The portion of the module disposed within the engine compartment includes a quick disconnect locking coupling providing for ready installation and removal of the dipstick, while providing protection against blow out of the dipstick and loss of vacuum pressure. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0010]    The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which: 
           [0011]      FIG. 1  is a representation of a dipstick module embodying various aspects of the present invention; 
           [0012]      FIG. 2  is a partial-view representation of an alternative embodiment of the inboard end portion of the dipstick module depicted in  FIG. 1 ; 
           [0013]      FIG. 3  is a partial exploded view showing the two major separable elements of a coupling of the dipstick module depicted in  FIG. 1 ; and, 
           [0014]      FIG. 4  is a side view, in section, of the outboard end of the dipstick module depicted in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    In one embodiment of the present invention as depicted in the several figures, it will be noted that the invention  10  comprises a dipstick module including an elongated dipstick  12  disposed within an elongated housing  14  having an inboard end  16  thereof mounted in an opening  18  in the wall of an oil reservoir  20  of a motor vehicle engine, and an outboard end  24  which is incorporated into a quick connect coupling  26  adapted to provide for rapid and easy insertion of the dipstick  12  into the present module in fluid-tight sealing relationship and subsequent withdrawal of the dipstick  12  from the oil reservoir, separately from those elements of the module which provide for the mounting and securing of the dipstick  12  with respect to the vehicle oil reservoir. 
         [0016]    Preferably this dipstick  12  is flexible along its length for slidable disposition within the elongated hollow, dipstick housing  14 . In a preferred embodiment this housing  14  comprises braided metallic strands disposed about a fluid impervious flexible inner lining  28 , thereby rendering the housing flexible and resistant to rupture. A typical housing exhibits an internal diameter of less than one inch and is capable of withstanding fluid pressures in excess of one hundred pounds per square inch. One suitable lining material is a polymeric material such as Teflon® which is resistant to the motor oil present in the oil reservoir. One skilled in the art will recognize that other suitable liner materials may be employed. 
         [0017]    In accordance with one aspect of the present invention, the inboard end  16  of the dipstick housing is removably anchored to a fitting  30  suitable for the interconnection of the housing  14  to the oil reservoir via the opening  18  through the wall of the reservoir  20 . As seen in  FIG. 1 , this fitting  30  may comprise a hollow tubular sleeve  32  having a first end  42  thereof adapted to be inserted into the inboard end  16  of the dipstick housing  14  and an externally threaded second end  34  adapted to be threaded through the opening  18  in the wall  20  of the reservoir. This fitting  30  further includes a tubular shroud  36  adapted to be threaded onto the sleeve  32 , thereby capturing, sealing, and anchoring the inboard end  16  of the dipstick housing  14  between the sleeve  32  and shroud  36 . 
         [0018]    As depicted in  FIG. 2 , alternatively, in lieu of threads on the sleeve  32  for anchoring the fitting  30  within the wall of the reservoir  20 , the fitting  30  may include a frictional circumferential surface  44  adapted to provide for a frictional fit of the sleeve  32  within the opening  18  in the wall of the reservoir  20 . In either embodiment, the fitting  30  is sufficiently secured within the opening  18  in the wall of the oil reservoir  20  as to preclude expulsion of the fitting  30  from the wall opening  18  under conditions of the buildup of inordinate pressure within the oil reservoir as will appear further hereinafter. 
         [0019]    The quick connect coupling  26  includes first and second major elements  46  and  48 , respectively. An outboard end of the dipstick  12  is anchored to the first major element  46  of the quick connect coupling  26  as by a set screw  52  ( FIG. 4 ). Referring to  FIG. 3 , the second major element  48  defines a passageway  50 . The outboard end  24  of the dipstick housing  14  is anchored to the second major element  48 , such that the passageway  50  allows for the passage of the inboard end of the dipstick  12  through the second major element  48  and into the housing  14 . 
         [0020]    The first major element  46  of the quick connect coupling  26  is of a knob geometry suitable for grasping in the hand of a user and includes a projection  54  extending inwardly from its inboard end  56 . This projection  54  is adapted to be releasably inserted into the open outboard end  58  of the second major element  48  for releasable fluid-tight interconnection of the first and second major elements  46 ,  48 . As seen in  FIGS. 3 and 4 , this projection  54  is provided with at least first and second outer circumferential grooves  60  and  62 , respectively, disposed at spaced apart locations along the length of the projection  54 . As will be discussed in further detail below, the circumferential grooves  60 ,  62  are adapted to engage respective structural elements internally of the second major element  48 . 
         [0021]    The interconnection of the first and second major elements  46 ,  48  effects fluid tight pressure sealing of the first and second major elements  46 ,  48  to one another, thereby effecting closure of the dipstick housing  14  and discouraging pressurized oil originating within the oil reservoir from escaping into the environment externally of the module  10 . The interconnection of the first and second major elements  46 ,  48  also provides for easy, quick connection and disconnection of the first major element  46  from the second major element  48  for purposes of removal and reinsertion of the dipstick  12  from and into the oil reservoir. 
         [0022]    As noted, the first major element  46  of the coupling  26  comprises a knob  68  having a shaped portion  69  thereof which preferably is contoured in a manner to facilitate grasping of the knob  68  in a user&#39;s hand. The first major element  46  also includes an elongated cylindrical projection  54  extending linearly from the inboard end  56  of the knob. This projection  54  is adapted to be received in locking liquid-tight sealing, but removable, relationship within the second major element  48  of the coupling  26  when the dipstick  12  is inserted within its housing  14 . Thus, the coupling  26  functions as an aid to lock the first and second major elements  46 ,  48  in engagement in order to preclude expulsion of the dipstick  12  and pressurized fluid from the reservoir into the atmosphere exterior of the module, such as during buildup of potentially damaging fluid pressure within the reservoir. Also, the coupling  26  functions to establish the extent to which the dipstick  12  may enter the housing  14 , and hence establishes the depth to which the inboard end  45  of the dipstick  12  may become immersed in fluid contained within the reservoir. 
         [0023]    As noted, the second one  48  of the two major elements of the quick connection coupling  26  is of a hollow, generally tubular geometry. The open outboard end  58  of this second major element receives internally thereof an “O” ring seal  70 , a coil spring  74 , a retention ring  76 , and a plurality of ball bearings  78 . The ball bearings  78  are partially embedded within appropriate through holes  80  in the body portion  84  of the second major element  48  of the coupling  26  at circumferentially spaced apart locations proximate the outboard end thereof. In the depicted embodiment, the through holes  80  are contoured to permit each ball bearing to project outwardly from both the inner and outer circumferences of the outboard end  58  of the second major element proximate its outboard end. 
         [0024]    As depicted in  FIG. 4 , the second major element  48  of the coupling  26  is provided with a first circumferential open groove  88  in the inner wall  53  of the second major element at a location approximately half-way between the opposite ends of the second major element. The first open groove  88  is sized to accept therein the distal end  55  of the projection  54  of the first major element of the coupling. Immediately adjacent the first open groove  88 , and on the outboard side of the first open groove  88 , there is provided a second circumferential open groove  90  which is of a larger outer diameter than the first open groove  88  and defines an annular receptacle for the ring seal  70 . The ring seal  70  provides a substantially fluid-tight seal between the first and second major elements  46 ,  48  when the first and second major elements  46 ,  48  are coupled. 
         [0025]    Externally of the outboard end of the second major element  48  there is provided a circumferential collar  91 . The collar  91  is selectively slidable along a portion of the outer wall  83  of the second major element  48  between an outer circumferential shoulder  92  defined by the outer wall  83  of the second major element  48  and a retention ring  76  disposed within a circumferential groove  96  proximate the outboard end the outer wall  83  of the second major element  48 . This collar  91  is of an inner diameter greater than the outer diameter of the outboard end of the second major element  48 , such that there is defined between the collar  91  and the outer wall  83  an open annular space  98 . 
         [0026]    Further, the collar is provided with a circumferential flange  100  disposed proximate the outboard end of the inner wall  102  of the collar. This flange  100  serves, among other things, to establish concentricity between the collar  91  and the underlying outer wall  83  of the outboard end of the second major element  48 . 
         [0027]    Within the annular space  98  between the collar and the outboard end of the second major element  48 , there is provided a coil spring  74  which encircles a portion of the outer wall  83  of the second major element  48 . This coil spring  74  is captured in the open annular space  98  between the collar  91  and the outer wall  83  of the second major element  48 , and between a circumferential flange  104  on the outer wall  83  of the second major element  48  and the circumferential flange  100  on the outboard end of the inner wall  102  of the collar  91 . The spring  74  thus functions to bias the collar  91  toward a position proximate the outboard end of the second major element  48  and in overlying relationship to the plurality of ball bearings  78 . 
         [0028]    As depicted, the retention ring  76 , disposed in the further groove  96  within the outer wall  83  of the outboard end of the second major element  48 , is adapted to halt the outward movement of the collar  91  and prevent the collar from sliding off the outboard end of the second major element  48 . 
         [0029]    The partial embedment of the plurality of ball bearings within their respective through holes in the wall of the second major element  48  proximate, but interiorly of, the retention ring  76 , provides for a relatively small portion of the outer surface of each ball bearing  78  to project radially inwardly from the inner wall  53  of the second major element into the passageway  50  of the second major element. In this manner, the ball bearings  78  are adapted to engage the projection  54  of the first major element  46  of the coupling  26 . To this end, the spring  74  functions to bias the collar  91  toward a position bringing the circumferential flange  100  on the collar  91  into circumferential register with the ball bearings  78 , thereby locking the ball bearings  78  into the circumferential groove  60  of the first major element  46  by the established maximum extent, hence releasably locking the first and second major elements of the quick connect coupling to one another. Conversely, the circumferential flange  100  on the collar  91  may be brought out of register with the ball bearings  78 , allowing the ball bearings  78  to withdraw from the circumferential groove  60  of the first major element, thereby allowing release of the first and second major elements  46 ,  48  of the quick connect coupling  26  from one another. 
         [0030]    As depicted, the central hollow passageway  50  the second major element  48  permits the passage through of the dipstick  12  (or for the introduction of lubricant fluid into the oil reservoir, if desired). The fitting  30  is configured so as to allow the inboard end  45  of the dipstick  12  to be fed through the hollow fitting  30  and into the interior of the reservoir to become immersed within the oil within the reservoir. 
         [0031]    When the first and second major elements  46 ,  48  of the coupling are fully joined (locked) to one another, the inboard end of the projection  55  enters into the groove  88  defined internally of the second major element  48  of the coupling  26 , and engages the ring seal  70  to establish a substantially fluid-tight seal of the passageway  50 . When the first and second major elements  46 ,  48  are fully engaged (including locking of the ball bearings in their respective detents), the foregoing described structure  10  defines a fluid-tight seal at a location approximately halfway between the opposite ends of the coupling  26 . 
         [0032]    Operationally, it is to be noted that full insertion of the projection  54  of the first major element  46  into the passageway  50  of the second major element  48  can only be accomplished when the collar encircling the second major element of the coupling is urged longitudinally inboard along the second major element against the force of the coil spring  74 , thereby moving the internal shoulder  100  of the collar  91  away from engagement with the ball bearings  78  in the wall  83  of the second major element  48 . Upon such retraction of the collar  91 , full insertion of the projection  54  into the passageway  50  of the second major element  48  serves to position the circumferential groove  60  of the first major element into alignment with the ring of ball bearings  78  disposed in the outboard end of the second major element  48 . Thereupon, the collar  91  may be released, resulting in movement of the internal shoulder  100  of the collar  91  into register with the ball bearings  78 , thereby locking the first and second major elements  46 ,  48  of the coupling  26  together. Decoupling of the first and second major elements  48  of the coupling  26  is effected by again urging the collar  91  inboard along the second major element  48 , thereby releasing the ball bearings  78  to the extent necessary for separation of the first and second major elements  46 ,  48 , hence disconnecting the coupling  26 . 
         [0033]    As depicted in  FIG. 4 , the inboard end of the first major element  46  of the coupling is provided with a blind bore  82  adapted to receive therein the outboard end  17  of the dipstick  12 . That portion of the dipstick which resides within such blind bore  82  is anchored therein as by a set screw  52 , or other suitable connector. Thus, withdrawal or insertion of the dipstick  12  from its housing  14 , and hence from the interior of the oil reservoir, may be accomplished by disconnecting the coupling  26 . Importantly, the first major element  46  of the coupling  26  is releaseably locked against expulsion of the dipstick  12  upon substantial buildup of pressure within the oil reservoir and/or within the dipstick housing  14  which is in fluid flow communication with the interior of the oil reservoir. 
         [0034]    As seen in  FIG. 1 , the dipstick module  10  may be secured, as by a bracket  64 , at a location within the engine compartment, for example, at a location where the first major element  46  is readily accessible for the insertion and withdrawal of the dipstick  12  into and out of the second major element  48 , the housing  14 , and the oil reservoir. When the present invention is so mounted, the coupling  26  may be readily and quickly decoupled, thereby providing for quick withdrawal of the dipstick  12  from the module. 
         [0035]    While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.