Abstract:
A fastening device having a pin with an enlarged head and a central longitudinal bore to receive a rod having a head with a drive receiving recess and a footed keeper. The pin and rod have adjacent surfaces that aid in the prevention of turning relative to each other. In use, the pin, with the footed keeper in alignment, is inserted to aligned openings in overlapping maps used in roadways and a tool is used to turn the keeper a quarter turn to prevent the pin from coming out of the opening and securing the mat.

Description:
This is a continuation of application Ser. No. 09/657,012, filed Sep. 7, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a device for securing articles together. In particular, the present invention relates to a device for securing together mats used as structural supports for roadways and the like. 
     2. Description of the Related Art 
     Many fastening devices for joining various elements are known in the art. A few examples of such devices are U.S. Pat. Nos. 5,779,422; 4,801,232; 4,498,827; and 2,811,765. Other fastening devices have specific applications. For example, U.S. Pat. No. 5,632,586 discloses an automatic twist lock primarily used with shipping containers, and U.S. Pat. No. 5,346,349 discloses a fastening device for assembly of components of pieces of furniture or furnishings in general. 
     A smaller number of such devices are used to interconnect and secure flat shaped components. For example, U.S. Pat. No. 4,604,962 discloses an interlocking assembly for modular loading dock units. 
     Rigid large sized industrial mats are used as structural supports. Multiple mats can be placed adjacent to each other and connected together to provide support for roadways and other structures. When adjacent mats are secured together, the collection of secured mats function as one large mat rather than a collection of individual mats. Any successful fastening device must provide substantial holding strength to secure the mats and prevent separation. Particularly, when mats are used in roadway surfaces, extreme pressures are placed on the adjoining mats and the locking mechanism. 
     Some devices in use to secure the mats include fasteners with carriage bolts that restrict lateral movement of the mats but do not successfully restrict vertical movement. With movement of the mats relative to each other, the carriage bolts often work their way out, presenting a hazard to personnel and vehicles using the mats. 
     Other fastening devices use a keeper drawn up by a screw; however, harsh conditions and contaminants such as mud, sand and/or debris can impair the operation of any threaded device or devices that allow contaminants to enter and impair their working mechanisms. The present invention does not utilize threaded elements and is better adapted to operate in harsh conditions. 
     SUMMARY OF THE INVENTION 
     The present invention provides a fastening device for fastening and securing adjacent panels or mats together by placement of the fastening device in slots in overlapping lips of adjacent mats and includes a keeper which is rotated under the bottom of adjacent mats to prevent removal of the fastening device. 
     The fastening device includes a rigid pin with an enlarged head, and a central bore. The pin is shaped to fit aligned slots or holes of adjacent mats, and the pin is generally of an oblong shape to resist rotation in the aligned holes. The depth of the pin is designed to match the depth of two overlapping mats. 
     The enlarged head of the pin prevents the pin from dropping through the mat hole and ideally is engineered and designed to allow the pin to drop to a level to be flush with the top of the mat when locked into place. The enlarged head of the pin has a top opening to the central bore which can also receive a protective cap. 
     The central bore of the pin receives a footed rod having an enlarged head with a drive receiving recess which can be protected by placing a protective cap in the top opening of the central bore of the pin. The footed end of the rod has a keeper aligned generally perpendicular to the rod and placed below and outside of the pin body. In its preferred embodiment, the keeper has a tapered or helical surface that allows easier rotation of the keeper during its initial contact with the bottom of the mat. The tapered feature provides some compression of the mats as the thickest portion of the keeper fully contacts the bottom of the mat. 
     In use, the pin, with its keeper in the unlocked position such that the keeper does not extend outside the longitudinal projected body of the pin, is inserted into aligned openings of the mated articles. A torque-applying tool is then inserted in the drive receiving recess to turn the rod and the keeper resulting in the keeper extending into the longitudinal projected volume of the bottom mat to prevent pin removal. The wall of the pin bore and midbody of the rod have interacting surfaces which aid in the prevention of free tuning relative to each other. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the fastening device of the invention with the keeper in alignment with the pin; 
     FIG. 2 is a perspective view of the fastening device of the invention with the keeper out of alignment with the pin; 
     FIG. 3 is a perspective view of the rod and keeper; 
     FIG. 4 is a cross-sectional view, partly cutaway, taken along lines  4 — 4  of FIG. 1; 
     FIG. 5 is a side view of the fastening device of the invention taken along lines  5 — 5  of FIG. 1; 
     FIG. 6 is a cross-sectional view, partly cutaway, taken along lines  6 — 6  of FIG. 4; 
     FIG. 7 is a top view of the fastening device of the invention taken along lines  7 — 7  of FIG. 1; 
     FIG. 8 is a perspective view of the fastening device of the invention before insertion into a pair of overlapping mats; and 
     FIG. 9 is a perspective view of the fastening device of the invention inserted and locked into pair of overlapping mats. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The fastening device of the invention shown in FIG. 1 includes an oblong shaped pin assembly generally indicated by the numeral  10  made of rigid material. As shown in FIGS. 7 and 8, pin  10  assembly has a vertically elongated body  10   a  having an oblong cross-sectional shape adapted to be received into aligned oblong holes or slots S formed in overlapping lips of mat B and T to prevent fee rotation of the pin body  10   a  within the mats. Mats B and T are conventional rigid support mats commonly used to provide structural support for roadways. Mats B and T are commonly made from rigid polymeric plastic materials well known in the art, and holes or slots S are provided in mats B and T for receipt of fastening devices such as bolts, pins, or the like. Holes or slots S have a recessed generally flat edge E extending completely around the periphery thereof. 
     Pin body  10   a  has a flat oblong bottom end  11  lying in a plane perpendicular to the longitudinal axis of pin body  10   a . Pin body  10   a  has an enlarged head  12  connected to the top of pin body  10   a  generally in the same oblong shape as the pin body  10   a  but larger than the oblong cross-section of pin body  10   a . The enlarged head  12  is configured to contact the recessed edge E of the mat T to prevent the pin assembly  10  from falling completely through mat hole or slot S. The enlarged head  12  has a top opening  14  to a central longitudinal bore  20  in pin body  10   a . The enlarged head  12  has a first indent  16  therein for receiving an extractor device and second indent  18  located on the opposite side of enlarged head  12  for receiving an extractor tool or device. As shown in FIGS. 2 and 5, a cavity  16   a  in pin body  10   a  is located beneath indent  16 , and a cavity  18   a  is located beneath indent  18  for receiving an extractor device. The first indent  16  and second indent  18  are shaped to allow a common extractor tool to gain access to the underside of the enlarged head  12  for removal of the pin assembly  10   a  from mat B and T. The pin body  10   a  and enlarged head  12  must be made of a durable material and preferably are made of a polymeric plastic material that can be designed for engineered failure of the enlarged head  12  to release mat B from mat T without tearing or deforming mats B and T when mats B and T may be forced apart prior to removing all pin assemblies  10  therefrom. 
     Extending from the bottom  11  of pin body  10   a  is an oblong keeper generally indicated by the numeral  30  which is preferably made of metal and is sized and configured such that in its rest position, the keeper  30  remains within the longitudinal projected volume of the pin body  10   a . In this rest position, keeper  30  and pill body  10   a  can be fitted into aligned holes S of the overlapping lips of mats B and T. The horizontal plane of the flat bottom  31  of keeper  30  is generally parallel to the horizontal plane of the enlarged head  12 . 
     Referring to FIG. 3, the keeper  30  is shown attached to, and preferably integrally formed with, the solid rod generally indicated by the numeral  40 . The keeper  30  can be shaped in numerous configurations, the preferred embodiment being a flat bottom and a top surface having a helical structure in which the top surface of the keeper  30  is sloped generally away from the longitudinal axis of the rod  40  to more easily first engage the underside of the mat. Keeper  30  has two identical semi-circular ends  30   a - 30   a  and two straight parallel sides  30   b - 30   b . Keeper  30  has two identical, helically tapered upper surfaces  32 — 32  at each end thereof which slope upward from parallel sides  30   b - 30   b  to crown  38 , and two identical helically tapered upper surfaces  34 — 34  at each end which slope upward from parallel sides  30   b - 30   b  to crown  39 . 
     As further shown in FIG. 3, solid rod  40  is received in top opening  14  of cylindrical longitudinal bore  20  in pin body  10   a . Solid rod  40  has an enlarged cylindrical head  41  received in enlarged longitudinal bore  20   a  axially aligned with bore  20 . Enlarged head  41  has a driver receiving recess  50  therein. If desired, a protective cap could be fitted into recess  50  to prevent dirt and other debris from filling recess  50  and preventing Allen wrench  51  from being inserted therein. The enlarged cylindrical head  41  is smaller than the enlarged head  12  of pin assembly  10 . Driver receiving recess  50  is preferably configured to receive a common Allen wrench type tool  51  shown in phantom lines in FIGS. 1,  2 , and  9 , but could be configured with a slot to receive a screwdriver-type device. Beneath cylindrical head  41  of rod  40  is located locking cylinder  40   a  having thereon four parallel longitudinal raised ridges  42 ,  44 ,  46 , and  48  thereon. Immediately beneath locking cylinder  40   a  is cylindrical shaft  40   b  which connects locking cylinder  40   a  with keeper  30 . Rod  40 , locking cylinder  40   a , cylindrical shaft  40   b , keeper  30 , head  41  and drive receiving recess  50  must be constructed of a durable material, and are preferably made of a metal alloy such as steel. 
     Referring to FIG. 2, with placement of Allen wrench  51  or other torque driving device in drive receiving recess  50 , and upon rotary motion 90 degrees clockwise or 90 degrees counterclockwise as indicated by the arrow  52 , keeper  30  is rotated outside the longitudinal projected volume of pin body  10   a  as indicated by the arrow  53 . When the keeper  30  engages the underside of mat B or T, the contact with the mat B or T prevents removal of the pin assembly  10  from the mat. An additional quarter turn or 90 degree rotation, clockwise or counterclockwise, of rod  40  correspondingly moves the keeper  30  a quarter turn or 90 degrees, and the keeper  30  rotates back to its rest position with the entire volume of keeper  30  within the longitudinal projected volume of pin body  10   a.    
     During rotation of rod  40  as shown in FIG. 2, the second tapered edge  32  of keeper  30  first contacts the bottom of mats B and T, and when the first and second crown  38  and  39  of the keeper  30  contact the bottom of mats B and T as shown in FIG. 9, the first and second crowns  38  and  39  of the keeper  30  in combination with enlarged head  12  provide a fastening force on the mats T and B, thereby securing the two mats T and B together. 
     Referring to FIG. 4, the cylindrical shaft  40   b  of rod  40  is shown fitted into central longitudinal bore  20  with central longitudinal bore  20  shaped to snugly surround shaft  40   b  to allow rotary movement of rod  40  relative to pin body  10   a , and first longitudinal raised ridge  42  and third longitudinal ridge  46  of locking cylinder  40   a  are shown. Shaft  40   b  is shown as connected to the midsection of keeper  30 , with keeper  30  being generally perpendicular to the longitudinal axis of shaft  40   b  and placed below the bottom  11  of pin body  10   a . Placement of keeper  30  relative to pin body  10   a  is in a manner to allow the keeper  30  to slide under the bottom of overlapping mats B and T. First indent  16  for receiving an extractor device shows configuration to allow for an extractor device to contact underside of enlarged head  12  to lift pin assembly  10  vertically out of the lips of mats B and T. The raised longitudinal metal ridges  42  and  46  contact the polymeric plastic wall of the pin bore which restricts free movement of rod  40  with respect to pin body  10   a.    
     Referring to FIG. 6, first raised ridge  42 , second raised ridge  44 , third raised ridge  46  and fourth raised ridge  48  are placed equidistant on locking cylinder  40   a  and are in contact with cylindrical bore  20   b  which is axially aligned with pin bore  20 . Cylindrical bore  20   b  has formed therein first bore recess  60 , second bore recess  62 , third bore recess  64  and fourth bore recess  66 . In locked position, ridges  42 ,  44 ,  46 , and  48  are received into first bore recess  60 , second bore recess  62 , third bore recess  64  and fourth bore recess  66 , respectively. The size of recesses  60 ,  62 ,  64  and  66  are shaped to the dimensions of the ridges  42 ,  44 ,  46  and  48 . The metal ridges  42 ,  44 ,  46  and  48  form a force-fit with polymeric plastic bore  20   a  when ridges  42 ,  44 ,  45 , and  46  are rotated away from and out of recesses  60 ,  62 ,  64  and  66 , thereby restricting free rotation of rod  40  within pin body  10   a  and locking rod  40  in a stationary position when ridges  42 ,  44 ,  45 , and  46  are seated in recesses  60 ,  62 ,  64  and  66 . The interaction of ridges  42 ,  44 ,  46  and  48  with the recesses  60 ,  62 ,  64  and  66  restricts free rotation of rod  40  within pin body  10   a  and allows for a type of locking when the ridges are seated in the recesses which can only be overcome by inserting an Allen wrench into recess  50  and applying sufficient torque to rod  40  force the ridges out of the recesses. There can be additional or fewer ridges and recesses resulting in additional or fewer locking positions. The ridges should be raised only a fraction of an inch for optimum restricted rotation. 
     In the process of manufacturing the fastening device of the invention, rod  40  and ridges  42 ,  44 ,  46 , and  48  are made of metal, and a polymeric plastic material is injected into a mold in the shape of pin body  10   a  having metal rod  40  therein, creating pin body  10   a  having bore recesses  60 ,  62 ,  64  and  66  corresponding to rod ridges  42 ,  44 ,  46  and  48 . 
     Referring to FIG. 7, enlarged head  12  can be seen with first extractor receiving indent  16  and second extractor receiving indent  18  with drive receiving recess  50 . Drive receiving recess  50  has two marking or shallow recesses  50   a  to serve as a position indicator of the relative position of rod  40  and keeper  30  to pin body  10   a.    
     Referring to FIG. 8, keeper  30  is shown outside of aligned slots S of bottom mat B and top mat T with keeper  30  in the rest or unlocked position. In FIG. 9, the fastening device has been placed in aligned slot S of top mat T and bottom B with keeper  30  rotated into locked position contacting the underside of mat B securing overlapping mats together in a vertical and horizontal manner.