Abstract:
A strip has a plurality of slots therein each which has a captured nut freely rotatable in the slot to be assembled to a work piece.

Description:
TECHNICAL FIELD 
       [0001]    The field of this invention relates to captured nuts on a work piece. 
       BACKGROUND OF THE DISCLOSURE 
       [0002]    There are assembly and installation situations where individual nuts are undesirable. In critical installation procedures where quick assembly is required or where the consequences of a loose or separated nut can be severe, nuts are desired to be preinstalled to reduce the risks of a loose or separated nut. 
         [0003]    One such critical installation is the mounting of a windage tray to an automotive engine. While the installation of windage tray is desirable to provide a slash barrier between the oil in the oil pan and the crank shaft which may provide an increase in effective horsepower of the engine, the accidental introduction of a separated nut to the internal space of engine assembly may cause extensive damage to the internal engine parts during later operation of the engine. 
         [0004]    Captured nuts both rotatable and non-rotatable have been known but are often made with extra members such as washers or the nuts need the aperture to be unthreaded near a capturing collar. Shortening of the threads in a threaded aperture degrades the holding power of a nut. 
         [0005]    What is needed is an improved captured nut assembly that reduces the risk of a separated nut. 
       SUMMARY OF THE DISCLOSURE 
       [0006]    In accordance with one aspect of the invention, a nut assembly has a retaining strip with a plurality of longitudinally spaced slots therethrough. The slots preferably have its length greater than a width. A plurality of nut bodies each have a drive section, a centrally located axially threaded bore, a first abutment shoulder and a collar extending from the first abutment shoulder. Preferably, the slot has a length larger than the diameter of the proximate end of the collar to provide longitudinal sliding movement of the nut along the longitudinal direction of the slot. The longitudinal axis of the slots is preferably substantially extending in the same direction as the longitudinal axis of the flexible retaining strip. 
         [0007]    The collar has a proximate end with an outer radius sized no greater than a width of the slot to engage within the slots. The abutment shoulder has a diameter greater than the width of the slot to abut the retaining strip adjacent the slots on one side of the strip. The collar has an integrally formed flange with a diameter greater than the width of the slot and positioned at an opposite side of the strip to secure the strip to the nut between the abutment shoulder and the flange. The flange is formed from a distal and radially outer section of the collar. A distal and radially inner section of the collar has an outer radius smaller than the outer radius of the proximate end. 
         [0008]    In one embodiment, the collar has its distal and radially outer section undergoing local disruption to provide the outward extending flange with a diameter greater than the width of the slot. The distal and radially inner section of the collar and the axially threaded bore is substantially undisturbed by the local disruption at the distal and radially outer section. The flange is preferably canted radially outward and axially away from the abutment shoulder. The collar also preferably has its proximate end with the outer radius being sized slightly under the width of the slot to allow the nut to rotate within the slot. 
         [0009]    In one embodiment, the retaining strip is contoured with varying width sections. In this embodiment, the retaining strip has its largest width sections containing the slots. The retaining strip is preferably flexibly resilient and normally biased to a flat straight position and made from spring steel. 
         [0010]    According to another aspect of the invention, a captured nut has a nut body with a drive section for engagement by a drive tool to rotate the nut body. The nut body has an abutment shoulder at one end. A tubular deformable collar extends from the abutment shoulder. A threaded passage extends through the nut body, abutment shoulder and the tubular deformable collar of a given outer diameter. The threaded passage is threaded in the collar section. The collar has a distal and radially outer section capable of being locally deformed to a greater diameter than the given outer diameter to form an annular groove to be able to capture a work piece about an aperture therethrough. A distal and radially inner section of the collar remaining substantially undeformed and has a portion of the threaded passage passing therethrough. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Reference now is made to the accompanying drawings in which: 
           [0012]      FIG. 1  is a perspective view of a strip nut being installed with a windage tray in accordance with one embodiment of the invention; 
           [0013]      FIG. 2  is a plan view of the strip and nut assembly shown in  FIG. 1 ; 
           [0014]      FIG. 3  is an enlarged cross sectional view taken along lines  3 - 3  shown in  FIG. 2 ; 
           [0015]      FIG. 4  is a fragmentary enlarged plan view of two of the nuts and strip with the nuts shown in two different longitudinal positions within the respective slots; 
           [0016]      FIG. 5  is a plan view of a modified strip with captured nuts; 
           [0017]      FIG. 6  is a side partially segmented view of the captured nut before assembly by local disruption; 
           [0018]      FIG. 7  is a side elevation view illustrating an anvil used in the deformation of the nut; and 
           [0019]      FIG. 8  is a side elevational and partially segmented view illustrating a modified anvil used in the deformation of a modified nut. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    Referring now to  FIG. 1 , an internal combustion engine  10  has a conventional block  11  and internal parts  12  such as crank arms and crankshaft which are mounted to the underside of the block  11 . A plurality of threaded studs  18  extend from the block  11  and engage apertures in the windage tray  20  which is mounted below the crankshaft. A plurality of captured nuts  22  mounted on a flexible strip  24  are threaded onto the studs  18  to affix the windage tray  20  in place. An oil pan  14  is mounted to the underside of the engine block  11  to enclose the windage tray and retains the oil therein. 
         [0021]    The strip  24  and nuts  22  are more clearly shown in  FIGS. 2-4 . Each nut  22  has a hex shaped outer drive section  26 . The captured nut  22  also has an annular abutment shoulder  28  and an axially extending collar  30 . A threaded aperture  32  is centrally located and axially extends entirely through the nut  22 . The threads  34  in the aperture  32  fully extend from the upper face  36  and into the collar  30 . The distal end may optionally have a chamfer (not shown). The nut may be made from steel such a S.A.E. 1065. Other materials may also be suitable depending on the application. 
         [0022]    The strip is made from spring steel and is thin enough to be yieldably resiliently flexible. The rest position of the strip is normally biased to its elongated flat straight position as shown in the Figures. A typical thickness is 0.3 mm for a strip that is about 490 millimeters long and about 19 millimeters wide. Of course different applications may require a different thickness for different amount of desired flexibility and resiliency. Other applications may have the retaining strip being rigid. 
         [0023]    The strip  24  has a plurality of elongated slots  40  which are spaced longitudinally along the strip. The slots  40  each have its longitudinal axis extending along the length of the strip. The slots have their width dimensioned to receive the proximate outer diameter section  42  of the collar that is in proximity of the abutment surface. The abutments shoulder  28  has a larger outer diameter to engage the side  44  of the strip about the slots  40 . 
         [0024]    The collar  30  has a axially distal and radially outer section  45  as best shown in  FIG. 6  that can be locally disrupted once positioned in the strip  24  to form a radially outwardly extending flange section  46  as shown in  FIG. 3  sized to be greater than the width of the slot to engage an opposite side  48  of the strip  40  about the slot  40  to capture the nut  22  in the slot  40 . The flange  46  is formed to axially capture the nut in the slot  40  but the nut is not crimped onto the sides  44  and  48  thereby allowing free rotation of the nut  22  in the slot  40 . As shown in  FIG. 3 , some vertical axial movement is allowed between the nut  22  and the strip  24 . Further, the flange  46  also allows longitudinal movement of the nut  22  along the length of the slot  40  as best shown in  FIG. 4  with each nut  22  shown in a different longitudinal position with its respective slot  40 . 
         [0025]    The local disruption of the distal and radial outer portion  45  does not affect the radially inner section  47  of the collar nor the threaded aperture  32  with its threads  34 . The slots  40  are centrally located to align with the studs  18  such that the nuts  22  can be aligned and threadably engaged and tightened onto the studs  18  sequentially one at a time. The longitudinal freedom of the nut  22  also provides for any manufacturing tolerance so that the nuts  22  can be axially aligned without any cant to eliminate any cross-threading or other improper threading to the studs  18 . 
         [0026]    The flange  46  as shown in  FIG. 3  has a taper or cant radially outward and away from the abutment shoulder  28 . As shown in  FIG. 7 , the taper is formed by an anvil  50  which has a corresponding anvil tapered striker zone  52  that strikes the distal radial outer section  45  of the nut  22  as shown in  FIG. 6  such that after striking the anvil it forms the tapered flange  46  as shown in  FIG. 7 . The nut is appropriately seated on a fixture (not shown) to receive the striking face of the anvil and be deformed by it. 
         [0027]    Alternate shaped nut  22  and anvil  150  are shown in  FIG. 8 . In this embodiment the nut  22  has a horizontally extending flange  148  formed by anvil  150  with striker zone  152  that is similarly horizontally extending. Again the spaced flange  148  and the abutment shoulder  28  are spaced about the strip  24  to axially retain the captured nut  122  but allows for free longitudinal sliding movement in the slot  40  and allows for free rotation of the nut  22  within the slot  40 . 
         [0028]    The longitudinal positions of the slots  40  may be asymmetrically or irregularly spaced along the strip  24  to correspond to likewise asymmetrically or irregularly positioned studs  18 . In this fashion, the strip  24  is not reversible and can only be fitted onto the studs with a single correct position. 
         [0029]    As shown in  FIG. 5 , a modified strip  124  has the slots  140  asymmetrically placed with respect to the main longitudinal axis of the strip  124 . The strip  124  is contoured about the slots  140  such that the strip area between two consecutive slots  140  is narrowed and offset from the slots to accommodate rises and shapes of the windage tray with may intrude into the ambient space  135  between two consecutive slots  140 . It is also foreseen that the strip edges  141  between the slots may also be contoured to accommodate other intrusions of work pieces such as windage trays. 
         [0030]    In this fashion, a strip of captured nuts  22  is easily used in an assembly process to assemble parts in a critical phase of assembly where smaller loose parts may otherwise cause grave consequences. The strip of captured nuts is flexible to accommodate manufacturing tolerances and has the nuts being capable of longitudinal movement along the slot to further accommodate manufacturing tolerances while allowing free rotation to tighten onto a threaded stud or bolt. The threads extend entirely through the internal passage of the nut to retain full gripping power of the nut to the bolt. 
         [0031]    Variations and modifications are possible without departing from the scope and spirit of the present invention as defined by the appended claims.