Abstract:
A latchable tie including a flexible strap with an elongated section having spaced apart first teeth, a head end, a tail end, an upper surface and a lower surface; and a head defining an outer end portion, an inner end portion joined to the strap, an outer opening in the outer end portion, an inner opening in the inner end portion, a channel extending between the outer opening and the inner opening and adapted to receive the tail end of the strap, a latch mechanism disposed in the channel and defining upwardly projecting longitudinally spaced apart second teeth for engaging the first teeth.

Description:
This application is a divisional of copending application Ser. No. 09/753,997 filed on Jan. 3, 2001 and which designated the U.S. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a clamping device for various objects and, in particular, to a cable tie for constraining plural objects. 
     A number of fastening or clamping devices have been devised for a variety of purposes. For example, clamps are used with electrical systems to connect electric shielding or insulation about electric wires, especially about electrical connectors that receive current carrying conductors. Clamps used in such applications are typically referred to as cable ties. 
     Cable ties generally are of one-piece construction, consisting of a metal or plastic band with a buckle or head attached rigidly to one end of the band. The free end of the band feeds through the buckle to form a loop enclosing the electrical wires. The buckle typically contains locking teeth or tabs which interlock with slots or teeth in the band during band adjustment to retain a desired periphery of the band. 
     Disadvantages associated with prior cable ties result from the bulky, irregularly contained buckles typically used. Such buckles, in addition to being aesthetically displeasing, frequently inflict damage or injury when inadvertently contacted by objects or persons. 
     The object of this invention, therefore, is to provide a cable tie with an improved low profile and smoothly contoured head. 
     SUMMARY OF THE INVENTION 
     The invention is a latchable tie for tying together plural objects and including a flexible strap with an elongated section defining a longitudinal axis and having a substantially uniform transverse width, a head end, a tail end, an upper surface and a lower surface; the lower surface defining a plurality of longitudinally spaced apart first teeth extending transversely to the axis; and a head defining an outer end portion, an inner end portion joined to the strap, an outer opening in the outer end portion, an inner opening in the inner end portion, a channel extending between the outer opening and the inner opening and adapted to receive the tail end of the strap, a bottom surface for contacting a portion of the objects being tied, an upwardly opening cavity disposed between the inner opening and the strap, and a cavity opening in the bottom surface and communicating vertically with the cavity; and the cavity and cavity opening each having a transverse width greater than the uniform transverse width of the strap. Also included is a latch mechanism disposed in the channel and defining upwardly projecting longitudinally spaced span second teeth for engaging the first teeth. After insertion of the tail end of the strap through the channel in the head and severing an excess portion of the tail end, the cavity and cavity opening retain a remaining portion of the tail end. 
     According to one feature of the invention, the strap further includes a transition section joining the elongated section and the inner end portion of the head, the cavity and cavity opening are straddled by transversely spaced apart connection portions of the head, the connector portions extend between the inner opening and the transition section, and the transition section defines an inclined ramp surface partially defining the cavity and sloping upwardly from the cavity opening toward the strap. The ramp surface upwardly directs the tail end of the strap to facilitate severing thereof. 
     According to another feature of the invention, the elongated section has a uniform transverse cross-sectional area, and the connecting portions together define between the inner opening and an inner end of the cavity opening a combined minimum aligned transverse cross-sectional area substantially equal to or larger than the uniform cross-sectional area. The minimum cross-sectional area prevents the existence of a rupturable weak point in the strap. 
     According to an additional feature of the invention, the connector portions are tapered downwardly from the inner opening to the transition section. The tapered connector portions desirably enhance the flexibility of the head. 
     According to further features of the invention, the transition section has transverse cross-sectional areas diminishing between the head and the elongated section, and also defines transversely spaced apart side surfaces and upper and lower connecting surface portions extending therebetween with at least one of the connecting surface portions defining transverse recesses. The transition section provides a structurally sound connection between the head and strap and the recesses facilitate bending of the transition section to accommodate the curvature of a bundle being secured. 
     According to still other features of the invention, the head further defines a bottom opening in the bottom surface and communicating with the channel; and the latch consists of a pawl defining the second teeth, one end portion disposed in the bottom opening and projecting below the bottom surface, and an opposite end portion movably joined to the head so as to allow movement of said one end portion into the channel. In response to forces produced by contact of the one end portion with a portion of the objects being tied, the second teeth on the pawl are forced into tighter engagement with the first teeth on the strap. 
     According to yet another feature of the invention, the tie includes a guide joined to the outer end portion and defining an uncovered, guide surface aligned with the longitudinal axis and terminating at the outer opening; the guide surface having a length l at least ¼ a length L of the channel. The guide surface is arranged to guide the tail end of the strap through the outer opening during use of the tie. 
     According to another feature of the invention, the guide also includes wall portions straddling the guide surface and having inner surfaces joined to the guide surface by concave joint portions. The wall portions further facilitate insertion of the strap into the head and the joint portions enhance the structural strength of the guide to prevent rupture thereof. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     These and other objects and features of the invention will become more apparent upon a perusal of the following description taken in conjunction with the accompanying drawings wherein: 
     FIG. 1 is a top perspective view of a cable tie according to the invention; 
     FIG. 2 is a bottom perspective view of the cable tie; 
     FIG. 3 is a bottom perspective view of a head portion of the cable tie; 
     FIG. 4 is a top view of the head; 
     FIG. 5 is a longitudinal cross-section taken along lines  5 — 5  of FIG. 4; 
     FIG. 6 is a transverse cross-sectional view taken along lines  6 — 6  of FIG. 4; 
     FIG. 7 is a transverse cross-sectional view taken along lines  7 — 7  of FIG. 4; 
     FIG. 8 is a partial longitudinal sectional view of the tie after insertion of the strap into the head; 
     FIG. 9 is a partial top perspective view of the tie after insertion and termination of the excess strap portion; and 
     FIG. 10 is a sectional view taken longitudinally in FIG.  9 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A tie  11  for securing together multiple articles such as cables is illustrated in FIGS. 1-10. Forming the tie  11  is an insertion guide portion  12 , flexible strap  13 , a head joining the guide portion  12  and the strap  13 , and a latch  15  attached to the head  14 . The bead  14  has a bottom retainer surface  25  and includes a body portion  16  having an upper head surface  17 , an outer end portion  18  joined to the guide portion  12  and an inner end portion  19  joined to the strap  13 . Defined by the body portion  16  of the head  14  is a channel  21  for receiving the strap  13  (FIGS. 8-10) during use of the tie  11 . The channel  21  extends between an outer opening  22  defined between the body portion  16  and the outer end portion  18  of the head  14  and an inner opening  23  defined between the body portion  16  and the inner end portion  19 . Forming the channel  21  are top wall  28  and side wall  29  portions (FIG. 5) of the body portion  16  of the head  14  which wall portions retain the strap  13  within the channel as shown in FIG.  8 . The inner end portion  19  of the head  14  further defines an upwardly opening cavity  26  extending between the inner opening  23  and the strap  13 . Communicating vertically with the cavity  26  and overlain thereby is an aperture  27  in the bottom retainer surface  25  and also extending between the inner opening  23  and the strap  13 . 
     The strap  13  includes an elongated section  31  with a longitudinal axis X and a transition section  32  joining the head  14  of the elongated section  31 . Defined by the elongated section  31  is a head end  35  joined to the transition section  32  and a tail end  36  for insertion into the channel  21  through the outer opening  22  of the head  14 . Also defined by the elongated section  31  are an upper surface  37  and a lower surface  38 , a major length of which defines a plurality of longitudinally spaced apart first teeth  39  extending transversely to the axis X. The elongated section  31  has a uniform cross-section and corresponding uniform width. Defined by the transition section  32  are side surfaces  41  and  42  joined by upper and lower connecting surfaces  43 ,  44  extending between the side surfaces  41 ,  42 . A plurality of transversely extending groove recesses  46  are formed in the upper connecting surface  43  and a plurality of similar transversely extending groove recesses  47  are formed in the lower connecting surface  44 . As shown in FIGS. 4 and 5 the transition section  32  has diminishing transverse cross-sections extending between the head  14  and the elongated section  31 . 
     The cavity  26  is partially formed by an inclined ramp surface  51  at an inner end of the transition section  32 . As shown in FIG. 5, the ramp surface  51  slopes upwardly from an inner edge  52  of the cavity opening  27  to the upper connecting surface  43  of the transition section  32 . Further defining the cavity  26  are inner surfaces  53 ,  54  of, respectively, connector portions  56 ,  57  of the head  14  which connector portions extend between the inner opening  23  and the transition section  32 . Preferably, both the cavity  26  and the another opening  27  have transverse widths substantially equal to the uniform width of the elongated strap section  31  so as to accommodate its passage after exiting the channel  21  of the head  14 . As shown in FIG. 5, the connector portions  56 ,  57  taper downwardly from the inner end portion  19  of the head  14  to the ramp surface  51  so as to have therebetween diminishing transversely aligned cross-sectional areas. Preferably however, a minimum combined aligned transverse cross-sectional area of the connector portions  56 ,  57  anywhere between the inner opening  23  and the inner end of the another opening  27  is substantially equal to the uniform cross-sectional area of the elongated strap section  31  so as to conserve material and not establish a structural weakness subject to rupture by tensile forces applied to the tie  11 . The combined transverse cross-sectional area at the inner end of the another opening  27  is shown in FIG.  6 . Thus, as shown most clearly in FIG. 10, that portion of the inner end head portion  19  forming the cavity  26  and the transition section  32  of the strap  13  together form a connector portion  60  having a top surface  58  and a bottom surface  59  converging between the upper head surface  17  of the body portion  16  and the head end  35  of the elongated section  31 . As also shown in FIG. 10, the connector portion  60  has along the longitudinal axis X (FIG. 1) a predetermined length D approximately two times the given length L of the channel  21  between the outer opening  22  and the inner opening  23 . Preferably, the top and bottom surface  58 ,  59  converge substantially uniformly at an angle A of approximately 8° as illustrated in FIG.  10 . 
     The latch  15  is a flexible pawl  61  located in a bottom opening  62  in the bottom retainer surface  25  of the head  14 . One end portion  64  of the pawl  61  is disposed in he bottom opening  62  and projects below the bottom retainer surface  25  while an opposite end  65  thereof is movably secured to the outer end portion  18  of the head  14 . Defined in an upper surface of the pawl  61  are a plurality of longitudinally spaced, transversely extending second teeth  68  arranged to engage the first teeth  39  in response to insertion of the elongated section  31  of the strap  13  into the channel  21  through the outer opening  22 . The pawl  61  is separated from the bottom surface  25  by longitudinally extending slots  69  each having an open outer end and an inner end closed by a radius joint  70  with the head  14 . 
     Defined by the guide portion  12  is an uncovered guide surface  71  aligned with the axis X and terminating at the outer opening  22  of the head  14 . Straddling the guide surface  71  are upwardly directed wall portions  73 ,  74 . Inner surfaces  75 ,  76 , respectively, of the wall portions  73 ,  74  are joined to the guide surface  71  by concave radius joint portions  77 ,  78  which strengthen the guide portion  12 . The guide surface  71  and wall portions  73 ,  74  direct movement of the tail end  36  of the elongated strap  31  through the outer opening  22  of the head during insertion of the strap  13  into the channel  21 . To facilitate that function, the guide surface  71  has a longitudinal length l least ¼ the longitudinal length L of both the body portion  16  and the channel  21  and preferably at least ½ thereof as shown in FIG.  4 . The minimum length of the guide portion  12  also provides strength to prevent rupture during application of tensile stress to the tie  11 . Also, as shown in FIG. 8, the maximum thickness of the head  14  is less than three times the uniform thickness of the strap  13  to provide the tie  11  with a low profile. 
     In use, the tie  11  is secured, for example, around a bundle of objects such as cables. During the securement process, the tail end  36  of the elongated strap  31  is passed, as shown in FIG. 8, sequentially through the outer opening  22 , the channel  21 , the inner opening  23  and the cavity  26 . The tail end  36  then is pulled to tightly tension the tie  11  around the bundle (not shown). Insertion of the strap  13  through the channel  21  of the head  14  is facilitated by guidance of the tail end  36  along the guide surface  71 . In a final tightened position of the tie  11 , the second teeth  68  on the pawl  61  engaged adjacent first teeth  39  on the lower surface  38  of the elongated strap section  31  so as to prevent reverse loosening movement of the strap  13  within the head  14 . As the tie is tightened on the bundle, engagement of portions thereof with the pawl  61  exerts an upwardly directed force on a lower surface of the pawl  61  so as to more tightly engage the first and second teeth  39 ,  68 . As the tail end  36  of the strap exits the inner opening  23 , engagement with the ramp surface  51  produces upward movement of the exiting strap as shown in FIG. 8 to facilitate severing of the exited excess strap portion. After the excess strap portion is severed, the remaining terminal portion  80  of the flexible strap flexes downwardly into the cavity  26  (FIGS. 9 and  10 ) so as to eliminate undesirable projections from the head  14 . Full reception of the terminal end  80  into the head is facilitated by the vertical communication between the cavity  26  and the cavity opening  27 . 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is to be understood, therefore, that the invention can be practiced otherwise than as specifically described.