Abstract:
A T-bolt pipe clamp of the quick-attach type in which a head portion of the T-bolt can be inserted into or removed from one of the connecting ends of the clamp. The clamp has first and second loop ends that are drawn together during tightening by a T-bolt fastener. The first loop end has a latch insert that accepts the head portion of the T-bolt and provides additional strength to the loop end. The latch insert can include a tab to help guide the T-bolt into the loop end and thereafter prevent it from too easily disengaging the loop end.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the priority of U.S. Provisional Application No. 60/658,475, filed Mar. 4, 2005. The contents of this provisional application are hereby incorporated by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates generally to pipe clamps and, more particularly, to T-bolt clamps used for mechanically fastening objects together. 
   DESCRIPTION OF RELATED ART 
   T-bolt clamps can be used as band clamps for securing tubular members together in a telescopic, or overlapping, manner. See, for example, U.S. Pat. Nos. 5,329,673 top Mason and 6,584,654 and 6,691,379 to Schaub. Alternatively, they can be used as pipe couplers such as in v-band clamps for connecting flanged ends of pipes or other tubular members together in an abutting configuration. See, for example, the prior art v-band clamp shown in FIG. 1 of U.S. Patent Application Publication No. 2005/0108859 to Amendolea et al. These various prior art clamps utilize a T-bolt fastener which includes a nut and threaded T-bolt having a head portion that is captively retained within a slotted bight at one end of the clamp band. 
   Prior art T-bolt clamps also exist that permit the head portion of the T-bolt to be disconnected from the slotted bight to permit quick attachment of the clamp without the need to unthread the nut from the T-bolt.  FIG. 1  shows one such prior art T-bolt clamp  10  that includes a latch assembly  12  connected to a flexible, flat metal band  14  having an inner surface  16  and an outer surface  18 . The band  14  has a first loop end  20  and a second loop end  22  and is adapted to mechanically fasten objects together, wherein the loop ends  20 ,  22  are formed by a portion of the band  14  being bent back and attached to the outer surface  18  of the band  14 .  FIG. 2  shows an alternative loop end design in which the loop end  20  is formed of a separate, wider piece of band material that is welded to the band  14  at each end of the piece. The attachment of the loop ends  20 ,  22  to outer surface  18  of the band  14  is done by spot welding. The first loop end  20  includes two laterally-spaced first end bearing loops  24  defining a first end cutout or slot  25  therebetween (shown in  FIG. 2 ). Likewise, the second loop end  22  includes two laterally-spaced second end bearing loops  26  defining a second end cutout (slot)  27  therebetween, as shown in  FIG. 1 . 
   The assembly  12  includes a T-bolt  30 , a trunnion  36 , and a nut  38 . The T-bolt  30  has a head portion  32  and a shank portion  34  with the head portion being pivotally received within bearing loops  24  of the first loop end  20  of the band  14  (shown in  FIG. 2 ). The trunnion  36  is pivotally received within the bearing loops  26  of the second loop end  22  of the band  14  (shown in  FIG. 1 ). The shank portion  34  of the T-bolt  30  extends through a passageway of the trunnion  36 , and the nut  38  is received on the shank portion  34  of the T-bolt  30 . As best seen in  FIG. 2 , the slot  25  includes a widened section that allows the head portion  32  to be inserted into and removed from the space with first loop end  24 . The slot  25  also includes a narrowed section bounded on either side by the bearing loops  24 . This construction provides the quick attachment feature to the clamp since it allows the clamp to be quickly attached to the object(s) being clamped by inserting the T-bolt head portion  32  into the slot  25  rather than having to unthread the nut  38 . Then, to tighten the clamp, the nut  38  is rotated into engagement with the trunnion  36  and this rotation is then continued while the loop ends  20 ,  22  are drawn towards each other as a result of the engagement of the head portion  32  with the bearing loops  24  and the trunnion  36  with the bearing loops  26 . 
   One of the drawbacks to the prior art T-bolt clamp  10  is that the slots  25 ,  27  are made directly in the band material, thus weakening the clamp  10 . When the head portion  32  of the T-bolt  30  is inserted into the slot  25  in the first loop end  20 , the head portion  32  moves forward to engage the first end bearing loops  24 , thus transferring a load to the band material, as best shown in  FIG. 2 . Where thinner sheet metal material or weaker steel stock is used for the band material, the bearing loops  24  of the first loop end  20  can spread apart when a tightening load is applied in a direction represented by arrow L, in which case the head portion  32  of the T-bolt  30  can disengage from the first end bearing loops  24 . In some prior art solutions, the thickness and width of the band  14  can be increased to provide strength to the loop ends  20 ,  22 . This increases the material cost and can makes the clamp  10  more cumbersome than may otherwise be needed for a particular application. Another prior art solution is to reduce the size of the head portion  32  of the T-bolt  30 , thus allowing for a smaller first end slot  25  in the band  14 . However, this solution may not provide enough surface area for the head portion  32  of the T-bolt  30  to transfer a load to the first end bearing loops  24 , thus weakening the clamp  10 . Another disadvantage of this prior art clamp is that the head portion  32  of the T-bolt  30  can spin when tightening or loosening the clamp  10 , such as with a socket tool, thereby disengaging the head portion  32  of the T-bolt  30  from the first end bearing loops  24  on the clamp  10 . 
   SUMMARY OF THE INVENTION 
   The present invention provides a T-bolt clamp that includes a band, fastening assembly, and latch insert that works in conjunction with the fastening mechanism to provide improved strength to the clamp. The band has first and second loop ends and a roundish body portion that extends circumferentially between the first and second loop ends. The fastening assembly is connected to the loop ends and it includes a T-bolt fastener and trunnion, with the T-bolt fastener including a T-bolt having a head portion that connects to the first loop end and an at least partially threaded shank portion that extends from the head portion to the second loop end. The trunnion is connected to the second loop end with the shank extending through the trunnion. The T-bolt fastener further includes a nut that threads onto the shank and engages the trunnion, whereby the loop ends can be drawn towards each other to tighten the clamp by further threading the nut onto the shank after it engages the trunnion to thereby draw the trunnion towards the head portion of the T-bolt. The first loop end includes a slot that permits the head portion of the T-bolt to be inserted into and removed from the first loop end without removal of the nut from the shank portion. The slot defines first and second bearing loops in the first loop end, with the head portion of the T-bolt being retained in the first loop end by the bearing loops during tightening of the clamp. The latch insert is located within the first loop end and it defines a cavity sized to receive the head portion of the T-bolt. The latch insert has an opening aligned with the slot of the first loop end such that the head portion can be inserted into the cavity via the slot and the opening. 
   Several embodiments of the latch insert and T-bolt are provided. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred exemplary embodiments of the invention will hereinafter be described in conjunction with the appended drawings, wherein like designations denote like elements, and wherein: 
       FIG. 1  is a perspective view of a prior art T-bolt clamp; 
       FIG. 2  is a perspective view of a portion of a prior art T-bolt clamp; 
       FIG. 3  is an exploded view of the T-bolt clamp made in accordance with the present invention; 
       FIG. 3   a  is a perspective view of a latch insert used in the T-bolt clamp of  FIG. 3 ; 
       FIG. 4  is a side elevational view of the T-bolt clamp of  FIG. 3 ; 
       FIG. 5  is a side elevational view of a portion of the T-bolt clamp of  FIG. 4 ; 
       FIG. 6  is a top plan view of a portion of the T-bolt clamp of  FIG. 4 ; 
       FIG. 7  is a perspective view of a latch insert made in accordance with a second embodiment of the present invention; 
       FIG. 8  is a front elevational view of the latch insert shown in  FIG. 7 ; 
       FIG. 9  is a rear elevational view of the latch insert shown in  FIG. 7 ; 
       FIG. 10  is a side elevational view of the latch insert shown in  FIG. 7 ; 
       FIG. 11  is a top plan view of the latch insert shown in  FIG. 7 ; 
       FIG. 12  is a sectional view of the latch insert taken along the  12 - 12  lines of FIG.  11 ; 
       FIG. 13  is a top plan view of the latch insert shown in  FIG. 7  before being bent; 
       FIG. 14  is a side perspective view of a portion of a T-bolt clamp made in accordance present invention using the latch insert shown in  FIG. 7 ; 
       FIG. 15  is a front perspective view of a portion of a T-bolt received within the latch insert shown in  FIG. 7 ; 
       FIG. 16  is a top perspective view of a portion of a T-bolt being inserted into the latch insert shown in  FIG. 7 ; 
       FIG. 17  is a top plan view of a latch insert made in accordance with a third embodiment, and showing the latch insert in the form of a blank prior to being bent into its final form; 
       FIG. 18  is a side view of the third embodiment of the latch insert in its final form; 
       FIG. 19  is a top view of the latch insert of  FIG. 18 ; 
       FIG. 20  is a perspective view of a second embodiment of a T-bolt that can be used with the T-bolt clamps of the first three embodiments; 
       FIG. 21  is a top view of the T-bolt of  FIG. 20 ; and 
       FIG. 22  is a side view of the T-bolt of  FIG. 20 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 3-6 , there is shown a T-bolt clamp  50  that has some of the same features as that of the prior art clamp  10  of  FIGS. 1 and 2 , and for that reason, features and components of T-bolt clamp  50  that are similar to those of prior art clamp  10  are identified using the same numerals. Clamp  50  includes a band  14  having a roundish body portion that extends circumferentially from a first loop end  20  to a second loop end  22 . Each loop end  20 ,  22  has a respective slot  25 ,  27  that defines a respective pair of bearing loops  24 ,  26 . The loop ends are formed using unitary end portions of the band  14  that are folded back onto the outer surface  18  of the band and attached by welding, crimping, mechanically interlocking them, or by any other suitable means. When forming the second loop end  22 , a trunnion  36  is placed within the loop end being formed prior to permanently attaching the band material to the outer surface. In this way, the trunnion  36  is captively retained in the second loop end  22 . Tightening of the clamp  50  is done as in the prior art clamp  10 . The shank portion  34  of the T-bolt  30  extends through a passage  37  in the trunnion and the nut  38  is then threaded onto the shank until it engages the trunnion  36 . The nut can directly engage the trunnion or can do so indirectly via a washer or other component(s). As the nut is further tightened, it bears against the trunnion  36 , thereby drawing the two loop ends  20 ,  22  together. 
   As in the prior art clamp, the slot  25  in the first loop end  20  is sized to receive the head portion  32  of a T-bolt  30 , with the so that it can be quickly attached and detached from the first loop end. However, whereas the prior art clamp  10  uses the bearing loops  24  to directly engage the head portion  32  during tightening of the clamp, in this embodiment  50  the clamp includes a latch insert  54  that is positioned within the first loop end  20 . Referring to  FIGS. 3   a  and  5 , the latch insert  54  includes a body  56  having a first surface  57  and a second surface  57 ′ and defining a first end  58 , an intermediate portion  60 , and a second end  62 . The second end  62  of the body  56  depends from the intermediate portion  60 , wherein the second end  62  is bent toward the first surface  57  of the intermediate portion  60  so that the second end  62  extends substantially perpendicular with respect to the intermediate portion  60  of the body  56 . The first end  58  of the body  56  also depends from the intermediate portion  60  and defines a pair of legs  68 ,  68 ′, wherein the legs  68 ,  68 ′ are bent towards the first surface  57  of the intermediate portion  60 , thus forming an arcuate shape. The legs  68 ,  68 ′ are adapted to receive the head portion  32  of the T-bolt  30  as shown in  FIG. 5 . An inner edge  70  of each leg  68 ,  68 ′ defines a recess area  72  adapted to receive the shank portion  34  of the T-bolt  30  as shown in  FIG. 6 . Referring to  FIGS. 4 and 6 , the latch insert  54  can be inserted into the first loop end  20  of the clamp  50 , wherein each leg  68 ,  68 ′ is received within the first end bearing loops  24  on the band  14 . 
   Referring to  FIG. 5 , when the latch insert  54  is received within the first loop end  20 , the second end  62  of the body  56  of the latch insert  54  extends through the first end slot  25  in a direction away from the outer surface  18  of the band  14 . The second surface  57 ′ of the second end  62  of the body  56  of the latch insert  54  abuts against an edge E (shown in  FIG. 6 ) of the slot  25 , thus preventing the latch insert  54  from disengaging from the first loop end  20 . The latch insert  54  can be made from a unitary piece of metal, such as steel, ceramic material, or polymeric material, such as plastic. In one embodiment, it is made from tempered steel and has a thickness that is between 130% and 200% the thickness of the band  14 . Thus, for example, the band can be made from 310¼ hard stainless steel, 1 mm to 1.5 mm thick, with the latch insert  54  being made from 301¼ hard stainless steel in a thickness of about 2 mm. 
   In operation, the latch insert  54  can be inserted through the first end cutout  25  into the first loop end  20  of T-bolt clamp  50 , wherein the legs  68 ,  68 ′ are received within the first end bearing loops  24  of the band  14  as shown in  FIG. 6 . Alternatively, the latch insert can be inserted into the first loop end  20  during the formation of that loop end and can be sized so that it is thereafter captively retained in the loop end, meaning that it then cannot be removed without at least some deformation of the loop end or latch insert. The head portion  32  of the T-bolt  30  passes through the slot  25  of the first loop end  20  and the recess area  72  of latch insert  54 , wherein the head portion  32  is pivotally received within the legs  68 ,  68 ′ on the first end  58  of the body  56  of the latch insert  54  as shown in  FIGS. 4 and 5 . The band  14  is then fastened around an object (not shown) and the shank portion  34  of the T-bolt  30  is inserted through a passageway  37  (shown in  FIG. 3 ) in the trunnion  36 . Referring to  FIG. 4 , a nut  38  can be threaded on the shank portion  34  of the T-bolt  30  and the clamp  50  can be tightened by rotating the nut  38  toward the trunnion  36 , thereby drawing the loop ends  20 ,  22  toward each other. The latch insert  54  provides additional strength to the first loop end  20 , thus preventing the bearing loops  24  from spreading apart and disengaging the T-bolt  30  from the first loop end  20  of the band  14  as shown in  FIG. 1 . The clamp  50  can be unloosened from an object by rotating the nut  38  away from the trunnion  36 . The second end  62  of the body  56  of latch insert  54  helps inhibit the head portion  32  of T-bolt  30  from easily backing out and disengaging the T-bolt  30  from the first loop end  20  of the band  14 . 
     FIGS. 7-13  show a second embodiment of a latch insert  80  that is similar to latch insert  54  except for the noted differences described below.  FIG. 13  shows the latch insert  80  before being bent from a flat unitary piece of metal. The latch insert  80  can also be molded from a ceramic material or a polymeric material, such as plastic. Referring to  FIG. 7 , the latch insert  80  includes a body  82  having a first surface  83  and a second surface  83 ′ and defining a first end  84 , an intermediate portion  86 , and a second end  88 . The second end  88  of the body  82  depends from the intermediate portion  86 , wherein the second end  88  is bent toward the first surface  83  of the intermediate portion  86  so that the second end  88  extends substantially perpendicular to the intermediate portion  86  of the body  82 . The first end  84  of the body  82  also depends from the intermediate portion  86  and defines a pair of legs  94 ,  94 ′. Referring to  FIGS. 7 ,  11 , and  13 , a recess area  100  is defined between an inner edge  98  of each leg  94 ,  94 ′. A lip  102  is also defined on the inner edge  98  of each leg  94 ,  94 ′. The difference between latch insert  54  and latch insert  80  is that the legs  94 ,  94 ′ are bent so that each end of the legs  94 ,  94 ′ is positioned to contact the first surface  83  of the intermediate portion  86 , thus forming a loop-shaped cavity  96  as shown in  FIGS. 7 ,  10 , and  12 . 
     FIGS. 14-16  show a T-bolt  30  inserted into latch insert  80 . In operation, latch insert  80  operates in the same manner as latch insert  54  except for several differences noted below. In clamp  50 , the second end  62  of latch insert  54  abuts against an edge E of the cutout  25 , thus preventing the latch insert  54  from disengaging from the first loop end  20  (shown in  FIG. 6 ). In contrast, the first end bearing loops  24  which enclose around the loop-shaped legs  94 ,  94 ′ prevent the latch insert  80  from disengaging from the first loop end  20  of the band  14  as shown in  FIG. 14 . Thus, the latch insert  80  is captively retained in the first loop end  20 . Referring to  FIGS. 15 and 16 , the inner edge  98  of each leg  94 ,  94 ′ adjacent each lip  102  represented by distance d 2  of recess area  100  contacts the head portion  32  of T-bolt  30 , thus preventing the T-bolt  30  from spinning when the clamp  50  is tightened around an object. 
   Referring to  FIG. 16 , the inner edge  98  of each leg  94 ,  94 ′ represented by distance d 1  of recess area  100  contacts the shank portion  34  as T-bolt  30  is inserted into the latch insert  80 , thus preventing misalignment of the shank portion  34  with the passageway  37  of the trunnion  36 . The distance d 1  is generally greater than the diameter of the head portion  32  of the T-bolt  30 . When the head portion  32  of T-bolt  30  is not properly mated with the surface  83  of the latch insert  80  as shown in  FIG. 16 , the head portion  32  will pass through the recess area  100  represented by distance d 1  without pulling against the inner edge  98  of each leg  94 ,  94 ′ of the latch insert  80 , thus weakening the clamp  50 . Thus, as shown in  FIG. 15 , when the elongated head portion  32  is axially aligned and seated within the cavity  96 , the head portion engages the inner surface  83  of the wider portions of the legs  94 ,  94 ′. However, if the head portion  32  is mis-inserted so that it is oriented radially as shown in  FIG. 16 , it will slip out of the first loop end  20  as a result of the distance d 1  between the legs  94 ,  94 ′ being greater than the thickness of the head portion. The second end  88  of the body  82  of latch insert  80  acts as a tab that can prevent the head portion  32  of T-bolt  30  from easily backing out of the slot  25 , thus disengaging the T-bolt  30  from the first loop end  20  whenever a force is applied on the T-bolt  30  in a direction toward the first loop end  20  as represented by arrow A shown in  FIG. 14 . Furthermore, as shown, this tab  88  extends out of the slot and includes a distal end that is bent away from the bearing loops, and this construction helps guide the head portion  32  of the T-bolt into the slot  25  when the head portion is being connected to the first loop end  20 . 
   With reference to  FIGS. 17-19 , there is shown a third embodiment  110  of a latch insert. This latch insert  110  can be used in the same manner as that of the embodiment of  FIGS. 7-16  and therefore the description of the remaining portions of the clamp are not repeated here.  FIG. 17  depicts a flat blank  112  used to construct the latch insert  110 . The blank  112  has a first end  114 , second end  116 , and intermediate portion  118 . It is made from flat strip metal and has a thickness of about 2 mm. Before bending to its final configuration, a cutout  120  is stamped into the blank  112 , and this cutout defines a pair of legs  122 ,  122 ′. The legs each have a first portion  124 ,  124 ′ having a first width and a second portion  126 ,  126 ′ having a second width. The two portions of each leg are separated by a step  125 ,  125 ′, although a more subtle transition can be used if desired. As with the first two embodiments, the latch insert  110  includes a tab  128 ; however, in this embodiment, tab  128  extends from the first end  114  rather than being located at the second end of the insert. In particular, the legs  122 ,  122 ′ do not terminate at distal, free ends as in the other embodiments, but instead are connected to each other by a bridging portion  130  at the free end  114 , and the tab  128  also extends from this bridging portion  130 . 
   To make the latch insert  110  from the blank  112  of  FIG. 17 , the blank  112  is bent at its intermediate portion  118  with the first end  114  being brought to a position adjacent the second end  116 . Also, the tab  128  is bent out away from the intermediate portion  118  and this provides the portion of the opening  132  through which the head portion of the T-bolt can be inserted. This tab  128  extends from a proximal end  134  at the bridging portion  130  to a distal, free end  136 . The tab is bent away from the legs and intermediate portion to form an angle as shown in  FIG. 18  that helps guide the T-bolt head portion into the slot of the loop end and into the opening in the latch insert. The distal end  136  can be further bent away from the remainder of the latch insert as in the second embodiment. 
   The result of this construction is a latch insert that operates in much the same fashion as the second embodiment. It includes a pair of spaced legs  122 ,  112 ′, an opening  130  to accommodate the head portion and shank of the T-bolt, and a tab to help guide the head portion into the loop end and retain it there. During use, the head portion of the T-bolt engages an inner surface  140  of the legs  122 ,  122 ′ which transfers the tightening force to the bearing loops via an outer surface  138  of the latch insert. 
   Referring now to  FIGS. 20-22 , an alternative embodiment  150  of a T-bolt is shown in which the shank  154  includes a specially shaped portion adjacent the T-bolt head  152 . In particular, the shank  154  has a first segment  156  that has a rectangular cross-section shape, and this transitions to a more conventional rounded segment  158  that is at least partially threaded along its length. The width d 3  of this first segment is just slightly less than the width d 1  of the opening between the first portion of the legs of the latch inserts of the prior embodiments where the shank passes through. As a result, once the shank is placed into this opening between the legs, it is unable to turn and this prevents rotation of the shank and head portions during tightening of the clamp. Although the dimension d 3  is preferably just slightly less than d 1 , it is sufficient if the diagonal of the segment  156  is larger than the width d 1  of the space, since this would only allow partial rotation with edges of the shank at opposite ends of the diagonal then engaging the inner edges of the legs of the latch insert and preventing further rotation. In the illustrated embodiment, the segment has a rectangular cross-sectional shape; however, other suitable non-circular cross-sectional shapes that can engage the inner edges of the legs of the latch insert can be used. For example, the segment  156  can be formed from an enlarged diameter rounded rod that is truncated at opposite sides of the segment to define two flats that allow the shaft to slide into the thinned portion of the opening in the latch insert. Thus, rather than having the rectangular cross-section shown in  FIG. 20 , the segment  156  will have two flats, one at the location where the  FIG. 20  lead line for reference numeral  156  ends, and one on the opposite side, with the upper and lower surfaces of this segment  156  being rounded rather than flat as shown. In any event, the height of the T-bolt  150  (measured in a vertical direction in  FIGS. 20 and 22 ) should be greater than the distance d 1  so that the shank of the T-bolt cannot be inserted in between the bearing loops in the wrong orientation. 
   It is to be understood that the foregoing description is not a description of the invention itself, but of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims. 
   As used in this specification and claims, the terms “for example,” “for instance,” and “such as,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.