Abstract:
A locking enclosure consisting of first and second members joined at one end by a living hinge and having, respectively, a flexible receptacle with an open recess and a foot portion configured to flex the receptacle as it enters the recess to lock the enclosure in a closed position, where damage to the living hinge and inadvertent opening of the enclosure are resisted by a pair of strips that project up from one end of the recess and down toward the recess bottom from the other end of the recess to engage corresponding slots in the foot.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to a device with a living hinge and a resilient locking mechanism for forming a locking enclosure and more particularly to such a locking enclosure for enclosing portions of at least two articles in an adjacent relationship where the articles may subject the enclosure to twisting forces and the locking mechanism makes the overall device surprisingly resistant to inadvertently and unexpectedly twisting open as a result thereof. 
     BACKGROUND OF THE INVENTION 
     In many instances, it is desirable to enclose portions of a plurality of relatively rigid articles in a close relationship. Initially, relative movement between the relatively rigid articles may be permitted, but ultimately such relative movement must be restrained. For example, relative movement is encountered during the assembly of radiant heating tubing for a driveway but is not desirable after the final radiant heating tubing array has been fixed in place. 
     In one system for providing such radiant heating, the radiant heating tubing is attached to a wire mesh as the radiant heating tubing is being placed over the wire mesh in a desired relationship. This attachment is accomplished using ties of various types which are wrapped around portions of the wire mesh and the radiant heating tubing. In some instances, where additional strength is required, rebar is added to the wire mesh or rebar is used in place of the wire mesh. In either construction, conventional ties are used to locate the rebar or wire mesh or to attach the radiant heating tubing to the conventional rebar or wire mesh. In other types of construction where conventional rebar is used to strengthen a structure, such as construction using cement or concrete, pieces of conventional rebar are attached together using the conventional ties as or before they are moved into the desired location before pouring the cement or concrete. While conventional ties generally achieve their intended purpose, workers who use them find them time-consuming and bothersome to use. 
     Therefore, there exists a need for a convenient, reliable, and economic locking enclosure, such as a resilient locking enclosure with a living hinge, that can be used in lieu of conventional ties. Also, the radiant tubing or other relatively rigid articles to be held in place in the locking enclosure may resist the restraint, applying twisting forces thereto that may damage or open the locking enclosure. A locking enclosure with a living hinge that can successfully resist these forces and will not inadvertently and unexpectedly twist open will constitute a particularly useful contribution to this art. 
     BRIEF DESCRIPTION OF THE INVENTION 
     This invention provides an improved locking enclosure with a living hinge that can be used in an automatic operation to enclose and restrain portions of at least two relatively rigid articles in a desired relationship without opening inadvertently when the locking enclosure is subjected to twisting forces. In preferred embodiments of the invention, the at least two relatively rigid articles comprise portions of wire mesh or rebar and portions of the radiant heating tubing used in the installation of radiant heating at desired locations. 
     In one preferred embodiment of the invention, the locking enclosure comprises first and second members each having an inner surface and an outer surface. Each of the members has a central body portion, an integral pivot portion, and an integral locking portion. The pivot portion provides a pivotal connection for mounting the first and second members for pivotal movement between opened and closed positions. The central body portion can be any length so long as it can surround the relatively rigid articles that are to be enclosed. 
     The pivot portion includes a living hinge extending between and integral with each of the pivot portions, optionally having additional means for guiding the pivotal movement of the two members from the opened position to the closed position while buttressing the stability of the locking enclosure at the hinge. The guiding means may comprise an arcuate groove in one of the pivot portions and an outwardly projecting portion on the other of the pivot portions where the projecting portion moves in the arcuate groove as the two members move from the opened toward the closed or locked position while the pivot portions move together. The groove and the outwardly projecting portion preferably are dimensioned so that, when in the closed position, the groove and the outwardly projecting portion are in a contiguous relationship. 
     The locking portion on the first member comprises a flexible receptacle portion having a recess formed therein, and the locking portion on the second member comprises a foot portion configured to fit within the recess. The recess in the receptacle portion has a base surface and overhanging walls at its distal and proximal ends. A first guide in the form of a protruding strip projects from the distal overhanging wall toward the base surface of the recess and a second guide in the form of a protruding strip projects from the base surface of the recess toward the proximal overhanging wall. 
     A longitudinal slot is formed in the bottom surface of the foot and is located and dimensioned to pass over and receive both of the protruding strips as the foot is inserted into the recess. Also, a widened recess is formed in the leading edge of the foot portion and communicates with the slot to facilitate the movement of the slot over the strip portions as the foot is inserted in the recess. 
     Apparatus for moving the locking enclosure devices from an opened position to a closed position to enclose at least two relatively rigid articles may use a feed track that supports a row of these devices in an opened position and urges the row of devices toward an end plate of the tool so that the forwardmost device of the row of devices is urged against the end plate. The end plate may have a generally planar surface to be contacted by the facing surface of the forwardmost device. The tool will also has a force applying mechanism for applying force to spaced apart abutment portions of the device. 
     A guide in the apparatus projects inwardly from the generally planar surface toward the row of locking enclosure devices and has a first guiding surface and, spaced therefrom, a second guiding surface. The forwardmost device in the row of devices is urged against the generally planar surface of the end plate so that a control portion of one of the two members is facing one of the first and second guiding surfaces and a control portion of the other member is facing the other of the first and second guiding surfaces. The force applying apparatus is located relative to the abutment portions so that the force applying apparatus contacts the abutment portions to apply a force thereto to move the control portions of the first and second members into contact with the first and second guiding surfaces to cooperate in controlling the movement of the control portions of the members over the first and second guiding surfaces. 
     The first and second guiding surfaces of the apparatus are contoured to move the first and second members from an open position to a closed position containing the at least two relatively rigid members between the two members. The flexible receptacle portion and the foot portion are located so that the application of force to the abutment portions moves the foot portion into the recess in the receptacle portion. One apparatus that may be used as explained in the preceding paragraphs for automatically applying locking enclosures is described in U.S. Pat. Nos. 4,801,061 and 5,350,267, the disclosures of which are hereby incorporated by reference. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrative and presently preferred embodiments of the invention are shown in the accompanying drawings in which: 
         FIG. 1  is a top plan view of a portion of a conventional radiant heating structure for use in providing radiant heating for a suitable location such as a driveway; 
         FIG. 2  is a cross-sectional view taken on the line II-II of  FIG. 1 ; 
         FIGS. 3 and 4  are front and rear elevation views of a prior art locking enclosure; 
         FIGS. 5A and 5B  are views, in perspective, of a prior art locking enclosure being subjected to twisting forces and opening as a result thereof; 
         FIG. 6  is a front elevation view of a locking enclosure in accordance with the invention; 
         FIGS. 6A and 6B  are enlarged partial views of the locking portions of the locking enclosure of the invention; 
         FIG. 6C  is a partial enlarged view of a triangular protuberance on a guide surface which helps direct locking portions into engagement; 
         FIG. 6D  is a bottom view of the locking foot of the invention; and 
         FIGS. 7-10  illustrate the movement of the locking enclosure of the invention from an open position to a closed position. 
     
    
    
     DETAILED DESCRIPTION 
     One of the many types of different installation designs used to provide radiant heating for a variety of structures such as driveways, athletic fields and others is illustrated in  FIGS. 1 and 2 . The design comprises a conventional wire mesh comprising intersecting wires  2  and  4  that are secured together at various intersections. The wire mesh is preferably laid over a bed of particulate material which, as illustrated in  FIG. 2 , comprises sand  6  but can comprise other types of particulate material such as pebbles, styrofoam, and other materials having similar characteristics. Radiant heating tubing  8  is installed over the wire mesh. As illustrated in  FIG. 1 , the radiant heating tubing  8  has a plurality of straight sections and curved sections that extend in different directions. The radiant heating tubing  8  has an inlet  10  and an outlet  12  so that a heating fluid may be passed through the radiant heating tubing. It is understood that there will be many sections of radiant heating tubing  8  for an overall structure. The wires  2  and  4  forming the wire mesh typically have diameters of between about 0.156 and 0.500 inch and the radiant heating tubing may have diameters between about 0.375 and 0.875 inch. The present invention, however, may be used for restraining a far wider range of rigid member sizes. 
     The construction of a prior art locking enclosure  20  (improved in accordance with the invention as described below in connection with later  FIGS. 6-10 ) is illustrated in  FIGS. 3-4 . This prior art locking enclosure comprises first and second members  22  and  32 . The first member comprises a pivot portion  24 , a central body portion  26  preferably integral with the pivot portion  24 , a locking portion  28  preferably integral with the central body portion  26 , and an abutment portion  30  preferably integral with the central body portion  26  and extending outwardly therefrom. Second member  32  comprises a pivot portion  34 , a central body portion  36  preferably integral with the pivot portion  34 , a locking portion  38  preferably integral with the central body portion  36 , and an abutment portion  40  preferably integral with the central body portion  36  and extending outwardly therefrom. Members  22  and  32  have facing inner surfaces  52  and  54  and outer surfaces  56  and  58  and abutments  30  and  40  have respective abutment surfaces  60  and  62 . Members  22  and  32  also include respectively abutments  48  and  50  positioned to move into an abutting relationship to limit the movement of the device  20  to a fully opened position. 
     Pivot portions  24  and  34  are joined by a living hinge  150  that extends between and is integral with pivot portions  24  and  34 . Living hinge  150  may be combined with guide apparatus  152  comprising an arcuate groove  154  formed in the bottom surface  155  of the pivot portion  24  and an arcuate projection  156  formed on the top surface  157  of the pivot portion  34  and shaped correspondingly to the arcuate groove  154  to facilitate rotational movement therebetween. The arcuate groove  154  may be tapered as shown with a wide entrance portion  158  and a narrow end portion  160  and the arcuate projection  156  has a narrow entrance portion and a wide end portion  164  dimensioned to fit snuggly and move in groove  154 . When the device is in the fully closed position the wide end portion  164  of the arcuate projection  156  is located in the wide entrance portion  158  of the arcuate groove  154  and the narrow entrance portion  162  of the arcuate projection  156  is located in the narrow end portion  160  of the arcuate groove  154 . The dimensions of the arcuate groove  154  and the arcuate projection  156  are such that, when the device  148  is in the fully closed position, the arcuate projection  156  and the arcuate groove  154  are in a contiguous relationship. This together with the locking portions  28  and  38  helps enable the enclosure to become rigid in its locked position. These features are described in more detail in U.S. Pat. No. 6,779,241, col. 10 lines  30 - 60 , the disclosure of which is incorporated by reference. 
     Locking portion  28  includes a flexible arm  72  with an upwardly opening recess  70 . Recess  70  in turn has a protruding strip  74  at its distal end projecting downwardly into the recess and locking portion  38  has a foot portion  78  that is contoured to cooperate with recess  70  when members  22  and  32  are in the closed position, as described in detail in U.S. Pat. No. 6,779,241 at col. 6 line  63  to col. 7 line  19 , the disclosure of which is incorporated by reference. 
     Unfortunately, prior art locking enclosures as described above and illustrated in  FIGS. 3-4  may inadvertently twist open. This is illustrated in  FIGS. 5A and 5B . Thus, when a lateral force F is applied to member  32  while member  22  remains generally stationary, member  32  may twist away from member  22  as shown in  FIG. 5A  with a concomitant lateral bending at living hinge  150 . Since the living hinge is not designed for such lateral movement, it may be permanently distorted impairing its intended functionality or it may tear if the lateral movement is too great. Additionally, foot portion  78  of locking portion  38  will slide out of recess  70  generally laterally along with the twisting movement member  32 . If and when the foot portion  78  of locking portion  38  clears strip  74  of recess  70 , locking portions  28  and  38  will be fully released as shown in  FIG. 5B . The present invention offers a unique modification to such prior art locking enclosures that prevents twisting relative movement between members  22  and  32  and hence both protects the living hinge from damage due to lateral movement between the members and prevents resulting inadvertent opening of the locking enclosure. 
     Turning now to  FIGS. 6 ,  6 A and  6 B, locking portion  28  of modified device  20   a  comprises first and second members  22  and  32  joined by a living hinge  150  as described above in connection with prior art device  20 . In a preferred embodiment of this invention, members  22  and  32  are integrally molded using a plastic material such as a polyethylene, a nylon or another plastic material having similar characteristics including particularly the ability to form an integral living hinge between the two members. Modified device  20   a  has a flexible receptacle portion  72  having a recess  70   a  formed therein, and the locking portion  38  on the second member comprises a foot portion  78   a  configured to fit within the recess. The recess in the receptacle end includes a base surface  71  and an overhanging wall  69  at its distal end. The outer surface of overhanging wall  69  is radiused as shown to form a guide surface  76 . Additionally, a guide protuberance  77 , preferably of a regular triangular in shape as shown in  FIG. 6C , may be provided to help facilitate the engagement of the locking portions by directing the foot portion into alignment with the recess. Preferably, a vertex of the triangular portion will be directed toward foot portion  78   a  to best cooperate with bevels  87 , which are described below. A first guide in the form of a protruding strip  74  projects from the proximal overhanging wall  73  toward the base surface of the recess. A second guide in the form of a protruding strip portion  75  is located at the distal end of the recess and projects upwardly from base surface  71  toward the distal overhanging wall  69 . 
     Locking portion  38  in turn includes a foot portion  78   a  with a bottom surface  79  configured to ride along guide surface  76  as locking portions  28  and  38  engage and foot portion  78   a  enters recess  70   a  in the receptacle portion. The leading or distal edge of the foot portion may include a beveled edge  81  which contacts the underside of overhanging wall  73  as locking portions  28  and  38  engage and foot portion  78   a  enters recess  70   a . As best seen in  FIGS. 6C and 6D , a longitudinal slot  80  with a bottom  82  is formed in underside  79  of the foot and is located and dimensioned to pass over and receive guide protuberance  77  when foot portion  78   a  is engaged in recess  70   a . Foot portion  78   a  also may include an entry  83  including a through-slot  85  extending from foot bottom surface  79  to the top of the foot. This through-slot is dimensioned to clear and engage strip portion  74  when the foot enters recess  70   a . Additionally, the leading edge of the foot may include levels  87  angled inwardly toward slot  80  to facilitate the initial engagement of locking portions  28  and  38 , first guiding the foot over protuberance  77  and later guiding through-slot  85  over strip  74 . 
     Thus, as members  22  and  32  are moved toward a closed position, bevels  87  facilitate the engagement of foot portion  78   a  with protuberance  77  as the underside  79  of foot portion  78   a  rides over guide surface  76  causing arm  72  to flex downwardly. As foot portion  78   a  moves into recess  70   a , the trailing end  91  of the foot clears the hook end  93  of distal overhanging wall  69  with strip  75  moving into slot  80  and flexible arm  72  moving back to its original position. The engagement of the slot with both the downwardly and the upwardly projecting strips ensures that the foot will be securely held in the recess in a manner that resists a release due to twisting in prior art devices, as illustrated in  FIG. 5A  or  5 B. This twisted release resistant configuration cooperates with living hinge  150  to produce a device which resists opening or destruction by twisting movement of locking enclosure device  20   a  surprisingly well, as compared to prior art devices (e.g., that of  FIGS. 3 and 4 ). Furthermore, this twisted release resistant configuration additionally cooperates with guide apparatus  152  to further enhance the resistance of the device to opening or destruction by twisting movement. 
     The movement of locking enclosure  20   a  from an open position as illustrated in  FIG. 7 , to a closed position as illustrated in  FIG. 10 , may be controlled by a tool of the type illustrated in U.S. Pat. Nos. 4,801,061 and 5,350,267 which are incorporated herein in regard to the structure and operation of the tool by reference thereto. In such a tool, a plurality of locking enclosures  20   a  in the opened position, illustrated in  FIG. 7 , are supported on a magazine and preferably resiliently urged toward the planar surface  92  of an end plate  90 . Pivot portions  24  and  34  of the locking enclosure preferably have a total thickness that is slightly less than the thickness of the central body portions  26  and  36 , the locking portions  28  and  38  and the abutment portions  30  and  40  so that the facing surface of the foremost device  20  is compatible with the generally planar surface  92 . 
     The movement of locking enclosure  20  from an open position to a closed position is illustrated in  FIGS. 7-10 . In  FIG. 7 , the foremost device  20   a  has been moved against the generally planar surface  92 . The tool has two spaced apart force applying plungers  126  and  128  having lower surfaces  130  and  132  located to contact a portion of the abutment surfaces  60  and  62  to apply an equal amount of force to the abutments  30  and  40 . As illustrated in  FIG. 7 , the portion  134  of the end plate  90  has been placed in contact with the portion  116  of a radiant heating tube  8 . As the plungers  126  and  128  begin to apply force, at least the control portion of the control surface  170  moves into contact with the first portion  102  and the control portion of the control edge  172  moves into contact with the first portion  96  to hold the pivotally connected members  22  and  32  in the opened position as the device  148  is moved downwardly over the generally planar surface  92 . As the force is continued to be applied, the foremost device  20   a  is moved over the generally planar surface  92  with at least a control portion of the control surface  170  in contact with the second portion  102  and the control portion of the control edge  172  almost out of contact with the first portion  96  so that the end device  20  is ready to be moved into a partially closed position as illustrated in  FIG. 8 . Guide surfaces  96  and  102  of guide  94  extend for a greater distance to insure that the device  20  remains in an opened position until the device has moved over the heating tube  8  and the wire  118 . 
     As the foremost device  20   a  continues to be moved downwardly over the generally planar surface  92 , the lower edges  174  of pivot portion  24  moves into contact with portion  116  to stop the downward movement of the foremost device  20   a . As the downward directed force is still being applied by the force applying plungers  126  and  128 , either the end plate  90  and therefore the tool is moved upwardly or the heating tube  8  and the portion  118  are moved downwardly away from the edge  134 . The locking portions  28  and  38  have been moved toward each other so that the foot portion  78  has moved into contact with the flexible arm  72  to begin to apply a force thereto and the heating tube  8  and the wire portion  118  are enclosed within the inner surfaces  52  and  54  of members  22  and  32 . The plungers  126  and  128  continue to apply a force to the abutments  30  and  40  to move the locking members  28  and  38  so that foot  78   a  deflects the flexible arm  72  and snaps into the recess  70   a  as the flexible arm  72  moves back to its original position as described above and illustrated in  FIG. 10 . Although illustrated in  FIG. 10 , the area enclosed by the inner surfaces  52  and  54  is slightly greater than the area of the heating tube  8  and the wire portion  118 , a tighter fit may of course be achieved by shortening members  24  and  34 . 
     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention.