Abstract:
A rivet-type fastener is disclosed, suitable for panel fasteners and other applications in which retention in a hole is required. The act of inserting the fastener expands fastener arms to secure the fastener in the hole, and positions locking protrusions of a post within notches of the arms, to lock the fastener within the hole. In some embodiments the fastener can be released, for removal and re-use.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention pertains generally to rivet type fasteners for attachment in holes of work pieces; and more particularly, to self-locking rivet type fasteners that can be released for removal and re-use  
         BACKGROUND OF THE INVENTION  
         [0002]    Various types of push-in fasteners have been used for engagement in holes of work pieces, to fasten together adjacent panels, or secure objects on the work piece. In a simple form for such a fastener, the work piece is provided with a hole. The fastener includes a head and a shank. The head is sized larger than the hole, so that the head will not pass into or through the hole. The shank includes outwardly biased but yieldable segments, frequently having an inwardly angled tapered tip. The expanded portion of the shank is nominally larger than the hole. Securing the fastener in the work piece is achieved by forcing the shank into the hole. As the shank enters and slides through the hole, the outwardly biased yet yieldable portions move slightly inwardly to allow full insertion of the fastener, until the head engages a surface of the work piece first entered by the fastener. A segment of the shank extends through the hole in the work piece.  
           [0003]    Due to the shape of the shank and the structure of the shank segments controlling the degree to which each can yield or deflect, withdrawal of the shank from the aligned apertures can be made difficult or prevented. A disadvantage of this type of fastener is that the insertion pressure required to cause the shank segments to yield may be disadvantageously high if the outward biasing force of the segments is sufficient to inhibit or prevent subsequent withdrawal of the fully inserted fastener.  
           [0004]    In another type of fastener, the shank includes a hollow core accessed through an opening in the head. A pin is provided. After the shank has been fully inserted, the pin is driven into the core of the shank, thereby urging the shank outwardly and securing the fastener in the hole of the work piece. Two-part fasteners of this type have disadvantages in that the parts can become separated from each other. Proper insertion of the pin into the shank may be troublesome if the access area is limited, or the individual using the fastener does not have sufficient dexterity to handle significantly small pins.  
           [0005]    A fastener with a retained movable pin is shown in U.S. Pat. No. 6,074,144. A disadvantage of this design is that multiple steps are required to pre-assemble the fastener before actual use. The pin must be positioned in a pre-locking position after initial molding of the fastener.  
           [0006]    Similar structures can be used as a fastening base or anchor on the surface of a work piece, rather than as a fastener joining two work pieces. The fastener is inserted in a work piece, and carries a superstructure on the surface of the work piece. The superstructure is configured for the attachment thereto of another work piece, covering or the like. It would be advantageous in many such applications if the fastener were easily removable and reusable.  
           [0007]    What is needed in the art is a self-locking rivet type fastener that includes a pre-lock configuration in which the shank is readily inserted into a hole, with minimal insertion pressure. What is further needed is a self-locking type rivet fastener that expands automatically as part of the insertion process, and that is locked into place upon full insertion. Further what is needed is a releasable type rivet fastener easily used and securely positioned, yet releasable for removal and re-use.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention provides a rivet-type fastener for securing within a hole of a work piece. The structure of the fastener causes automatic expansion of the fastener as the fastener is inserted in the hole, and engages locking members to secure the fastener in the hole.  
           [0009]    In one aspect thereof, the invention provides a fastener for a work piece with a base and first and second arms attached to the base and extending outwardly therefrom. The first and second arms each include proximal segments and distal segments conjoined at ends thereof. A post extends inwardly between the arms, from the conjoined distal segments toward the base. The arms and the post have cooperating structures for spreading the arms and locking the arms in a spread position, as relative axial movement occurs between the arms and the post.  
           [0010]    In another aspect of the invention, a fastener is provided with a base having a surface defining a channel, and opposed arms joined to the base in spaced relation on opposite sides of the channel. The arms include distal segments. A post is joined to the distal segments of the arms and extends between the arms towards the base. The post includes a transverse bar between the arms and aligned with the channel. Lateral protrusions extend outwardly from the post, and have tips. Notches in the arms engage the tips of the lateral protrusions in a locked position.  
           [0011]    In still another aspect thereof, the invention provides a rivet-style fastener with a base having a surface defining a channel. First and second opposed arms are joined to the surface of the base, in spaced relation to each other, and on opposite sides of the channel. The arms include relatively thicker proximal segments and relatively thinner distal segments. A post is joined to the distal segments and extends between the arms towards the base. The post includes a transverse bar between the arms and aligned with the channel. The bar has a length greater than the width of the hole. Lateral protrusions extend outwardly from the post, and have wedge surfaces ending at protrusion tips. Notches are provided in the proximal segments for engaging the tips of the lateral protrusions. Ramp surfaces on the arms direct the tips from the unlocked position to a locked position in which the tips are engaged by the notches, and the arms are deflected outwardly.  
           [0012]    An advantage of the present invention is providing a unitary rivet-style fastener, with automatic locking structures activated upon insertion of the fastener in a work piece.  
           [0013]    Another advantage of the present invention is providing a fastener for a hole in a work piece that locks during insertion and can be unlocked for removal and re-use.  
           [0014]    Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is an elevational view of a self-locking rivet fastener according to the present invention;  
         [0016]    [0016]FIG. 2 is a perspective view of the fastener shown in FIG. 1;  
         [0017]    [0017]FIG. 3 is a perspective view of the fastener shown in FIGS. 1 and 2, but showing the lower side of the fastener from that shown in FIG. 2;  
         [0018]    [0018]FIG. 4 is a perspective view of the fastener shown in FIG. 3, illustrating partial insertion of the fastener in a work piece;  
         [0019]    [0019]FIG. 5 is an elevational view similar to FIG. 1, but illustrating full insertion of the fastener in the work piece;  
         [0020]    [0020]FIG. 6 is an elevational view of a second embodiment of the fastener according to the present invention; and  
         [0021]    [0021]FIG. 7 is a perspective view of yet another embodiment of the fastener according to the present invention. 
     
    
       [0022]    Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]    Referring now more specifically to the drawings, and to FIG. 1 in particular, numeral  10  designated a fastener of the present invention. Fastener  10  is useful in fastening together adjacent panels (not shown) having apertures therethrough. Fastener  10  also may be used as an anchor to which other structures can be secured, in which case fastener  10  can be inserted in a single work piece  12 , as shown in FIGS. 4 and 5.  
         [0024]    Fastener  10  includes a base  14  that may be of a variety of shapes and configurations, depending on the application of and use for fastener  10 . FIG. 5 illustrates fastener  10  in a vertical orientation in work piece  12 , with base  14  above work piece  12 ; however, it should be understood that fastener  10  also can be used in applications wherein base  14  is below, along side or oriented angularly with respect to work piece  12 . Terms such as “top”, “bottom”, “up”, “down” and variations thereof are used herein for ease in description only, and are used with respect to the orientation of the various views in the drawings. Thus, the terms are not to be understood as limitations on the orientation of fastener  10 , or how it may be used.  
         [0025]    In the embodiments illustrated, base  14  is a substantially flat, rectangular, plate-like structure having a top surface  16 , a bottom surface  18 , side surfaces  20  and  22  and end surfaces  24  and  26 . While base  14  is illustrated to be rectangular in the drawings, base  14  could be of other shapes. Additionally, for fastening purposes, top surface  16  can carry a variety of superstructures and fastening components, as necessary. As illustrated in FIGS. 1 through 5, base  14  includes a pair of slots  28  and  30  extending therethrough, from side surface  20  to side surface  22 , intermediate top and bottom surfaces  16  and  18 . Slots  28  and  30  can be used, for example for receiving tabs from panels or other components hung on or secured to fastener  10 .  
         [0026]    Bottom surface  18  defines a rectangular channel  32  having channel sides  34  and  36  and a channel floor  38 . Channel sides  34  and  36  angle outwardly from channel floor  38 , so that the opening to channel  32  is wider than channel floor  38 .  
         [0027]    Channel  32  extends between side surfaces  20  and  22  and separates bottom surface  18  into bottom surface segments  18 A and  18 B. Depending on the size, shape, application and use of base  14 , channel  32  may be disposed intermediate side surfaces  20  and  22  or end surfaces  24  and  26 , perpendicular thereto or at an angle, and in shapes other than the rectangular shape shown. An aperture  40  is formed in base  14 , having openings in and extending from channel floor  38  to top surface  16 .  
         [0028]    First and second arms, designated  50  and  70  respectively, are connected to base  14  and extend outwardly from bottom surface  18  on opposite sides of channel  32 . When viewed from either side of fastener  10 , arms  50  and  70  are mirror images of each, being similarly shaped and oppositely directed so as to face each other. Arms  50  and  70  have relatively thicker proximal segments  52  and  72  nearest base  14 , and relatively thinner distal segments  54  and  74  furthest from base  14 . Proximal segments  52  and  72  angle outwardly, slightly, from base  14 . When viewed in side elevation as shown in FIG. 1, arms  50  and  70  define a slight pear shape, in the unlocked position of fastener  10 , as shown. A wider middle is provided near the junction of proximal segments  52  and  72  with distal segments  54  and  74 , and narrower ends both at base  14  and distal segments  54  and  74 .  
         [0029]    Proximal segments  52  and  72  define notches  56  and  76 , respectively, generally aligned with and facing each other near ends  58  and  78  of proximal segments  52  and  72 , joining distal segments  54  and  74 , respectively. Notches  56  and  76  are defined by intersecting walls  60 ,  62  and  80 ,  82  respectively. Ramps  64  and  84  extend from ends  58  and  78 , respectively, each angling inward and toward base  14 , intersecting with walls  62  and  82  of notches  56  and  76 , and forming lips  66  and  86 , respectively.  
         [0030]    Distal segments  54  and  74  extend from proximal segments  52  and  72 , respectively, curving inwardly toward each other and forming loops  68  and  88 , respectively, conjoined at a post  90 . Loops  68  and  88  are pliable, accommodating deformation thereof, to enable relative axial movement between post  90  and proximal segments  52  and  72 . Post  90  extends from conjoined distal segments  54  and  74  toward base  14 , between arms  50  and  70 . A transverse bar  92  is provided at the top of post  90 , bar  94  being aligned with channel  32 , but spaced therefrom in an unlocked, relaxed condition of fastener  10 , as shown in FIGS.  1 - 3 . Bar  92  is sufficiently long to extend beyond the widths of arms  50  and  70 . The width of bar  92  is less than the opening to channel  32 , so that bar  92  will fit in channel  32 , against channel floor  38 . In the embodiment of fastener  10  shown in FIGS.  1 - 5 , a pin  94  extends from bar  92  through aperture  40 , terminating slightly beyond top surface  16 .  
         [0031]    First and second protrusions  96  and  98  project laterally from post  90 , and have outer tips  100  and  102 , shaped to be received in notches  56  and  76 , respectively. Protrusions  96  and  98  have wedge surfaces  104  and  106 , respectively, that extend angularly from tips  100  and  102 , both inwardly toward post  90  and upward toward bar  92 .  
         [0032]    In the use of fastener  10 , a hole is provided in work piece  12  sufficiently wide for arms  50  and  70  to be pushed therethrough, but sufficiently narrow that the fit of arms  50  and  70  is snug, with some resistance. The insertion of fastener  10  is commenced with fastener  10  in a relaxed, unlocked position as shown in FIGS.  1 - 3 . The width of the hole in work piece  12  can be slightly smaller than the widest dimension defined by arms  50  and  70 . However, the hole should be greater than the dimension defined between tips  100  and  102 , and the thickness of distal segments  52  and  72  in the region of protrusions  96  and  98 . The space between arms  50  and  70 , and the widths thereof can be such that a round hole can be provided in work piece  12 , or the configuration may be such as to require an oblong hole or other shape. With fastener  10  properly oriented in work piece  12 , the hole in work piece  12  directly beneath bar  92  is narrower than the length of bar  92 .  
         [0033]    Loops  68  and  88  are placed in the hole of work piece  12 . As force is applied, and fastener  10  is advanced in the hole, proximal segments  52  and  72  encounter the side of the hole in work piece  12 . With additional insertion force applied to base  12 , arms  50  and  70  deflect slightly inward, until the widest portion thereof passes through the hole. The gently curving shape of the outer surfaces of arms  50  and  70  cause the inward deflection of arms  50  and  70  to occur smoothly and easily. After the widest portions thereof pass through the hole in work piece  12 , arms  50  and  70  spring outwardly.  
         [0034]    At about the same position, bar  92  will come to rest against work piece  12 , without advancing through the hole in work piece  12  due to the length of bar  92 . Continued insertion of fastener  10  occurs without further movement of post  90 . As proximal segments  52  and  72  are pushed further into work piece  12 , loops  68  and  88  begin to flatten, and ramps  64  and  84  come into contact with wedge surfaces  104  and  106  respectively. Sliding movement of ramps  64  and  84  against wedge surfaces  104  and  106  causes spreading between proximal segments  52  and  72  near ends  58  and  78 .  
         [0035]    Bar  92  enters channel  32  as bottom surface  18  approaches work piece  12 , so that bottom surface  18  can rest flush against work piece  12 . The outward tapers of channel sides  34  and  36  direct bar  92  to the bottom of channel  32 , against channel floor  38 . When fastener  10  is fully inserted and locked, bar  92  is secured in channel  32 , between channel floor  38  and work piece  12 .  
         [0036]    As bar  92  comes to rest against channel floor  38 , tips  100  and  102  of protrusion  96  and  98  slide past lips  66  and  86 , lodging in notches  56  and  76 , respectively. Arms  50  and  70  are sufficiently spread to prevent withdrawal of fastener  10  from the hole in work piece  12 . With protrusions  96  and  98  lodged between arms  50  and  70 , inward deflection of arms  50  and  70  is inhibited. Thus, fastener  10  is locked in work piece  12 , and can not be withdrawn easily.  
         [0037]    An advantage of the present invention, in some embodiments thereof, is that fastener  10  can be unlocked and withdrawn. From the locked position shown in FIG. 5, axial pressure is applied to pin  94 . Tips  100  and  102  are forced downwardly, past lips  66  and  86 , thereby unlocking the fastener. Only minimal distortion of tips  100  and  102 , and/or of lips  66  and  86  is required to dislodge tips  100  and  102  from notches  56  and  76 , thereby unlocking fastener  10 . The fastener can then be pulled outwardly from work piece  12 .  
         [0038]    The self-locking feature of the present invention can be used advantageously without the unlocking feature of the invention. FIG. 6 illustrates a second embodiment  120  of the invention that does not include aperture  40 , or pin  94  extending from bar  92 . Further, the present invention can be made unlockable without pin  94 . FIG. 6 illustrates a third embodiment  130  that includes aperture  40 , as described previously, without pin  94  extending therethrough from bar  92 . To unlock third embodiment  130 , an awl, punch or similar probe-like instrument is inserted through aperture  40  against bar  92 . Continued pressure from the instrument against bar  92  provides the aforedescribed unlocking by dislodging tips  100  and  102  from notches  56  and  76 .  
         [0039]    Variations and modifications of the foregoing are within the scope of the present invention. It is understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art.  
         [0040]    Various features of the invention are set forth in the following claims.