Abstract:
A coupling device ( 1 ) for releasably connecting tubular elongate members ( 4, 5 ) with improved efficiency. The coupling device ( 1 ) comprises first and second end piece connectors ( 2, 3 ) which are threadably secured or otherwise attached to connection ends ( 6, 7 ) of first and second tubular elongate members ( 4, 5 ). First and second end piece connectors ( 2, 3 ) are connected by rotating each end piece connector ( 2, 3 ) a minimal amount relative to each other, such that the rotation simultaneously locks end piece connectors ( 2, 3 ) together and engages mating tapers ( 31, 32 ) thus sealing the two end piece connectors ( 2, 3 ) and creating a leak proof seal. Coupling device ( 1 ) is just as easily disengaged, by rotating the two end piece connectors ( 2, 3 ) each in the opposite direction from engagement. In this way, the coupling device ( 1 ) provides a quick, easy and effective sealing mechanism especially useful to carpet cleaners who need to repeatedly connect and disconnect sections of vacuum hoses throughout their workday.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to hose couplers, and more particularly it relates to an improved vacuum hose coupling device and method of connecting hoses useful to carpet cleaners. 
   2. Description of Prior Art 
   Various coupling devices are known in the art. 
   U.S. Pat. No. 4,625,998 to Donald A. Draudt (1986) discloses a swivel hose ‘end piece connector’ but there is no locking, sealing, or release mechanism provided in association with the connection of two hoses. U.S. Pat. No. 5,257,836 to Peter J. Smith (1993) provides a quick and easy pipe coupling for field workers but it uses an ‘elastomeric’ sealing means of which are known in the art to degrade and leak over time, especially in the presence of water based chemicals commonly used in carpet cleaning. U.S. Pat. No. 5,407,236 to Ernst Schwartz, et al. (1995) discloses an innovative hose coupling which could be modified for use by carpet cleaners but the coupling can only be disengaged with the aid of an auxiliary tool. 
   For carpet cleaners, coupling devices for releasably connecting sections of vacuum hose have evolved from single insert to multi-component types. The three most common coupling devices in use by carpet cleaners are:
         (1) Single insert coupler: comprising a symmetric tube body of about twice the length of the diameter of the hose being coupled is typically made of hardened plastic or metal with circumferential notches or barbs. The insert is ‘wedged’ into each hose end and the notches or barbs are meant to lock the coupler in place and thus hold the hoses together.   (2) Three-part coupler: two end piece connectors are each fixedly threaded onto each hose end, then an insert as described above is wedged into the free end of each end piece connector thus coupling the hoses.   (3) Four part coupler: the same two end piece connectors and insert are connected as described above, then a pair of straps straddle the coupling device and prevent it from being pulled apart.       

   There are numerous problems with these prior art couplings: 
   Single insert coupler: Vacuum hoses are typically made of hardened plastic with little elasticity and the insert is typically made of an even more rigid material; this makes for a physically trying experience wedging the insert into each hose end. During use, hot fluids and air passing thru the sections of hose cause differential swelling between the hose and insert and this swelling can result in leakage of air and fluid around the hose end and insert. Eventually, this coupling device fails as the swelling becomes so extreme that the insert slips out of the hose end and may even never to seal properly again. Another problem with ‘insert’ couplings is that since the insert is of smaller inner diameter (“ID”) than that of the hose itself, flow is restricted. Strands of hair and other debris accumulate at these restrictions over time and create a physical blockage in the hose. The jagged hose ends being fully exposed, detract from the appearance of this coupling device. 
   Three part coupler: The two end piece connectors hide the jagged hose ends and thus improve the appearance of the coupler plus the two end pieces connectors provide a more secure attachment to the hose ends by means of threads along their interior surface whereby each end piece connector engages circumferential grooves along the perimeter surface of its respective hose end. Unfortunately, the same insert as described above is typically used to couple the two end pieces connectors and this weak connection allows this coupling device to pull apart under tension just like the single insert coupling device. Plus, the insert restricts flow, and accumulates debris. Manufacturers seem to have added parts, expense, and complexity yet still have not solved the problems—flow restriction, leakage, and hose separation. 
   Four part coupler: This style of coupling device solves the ‘separation’ problem by using two straps that are secured to vacuum hose beyond the coupler itself then buckled together. However, these straps add girth to the hose causing it to ‘hang-up’ on obstacles along its path. The straps also add complexity, labor, parts, and expense. And the insert is still required, so leakage still occurs; especially as the hoses heat and swell with age. Even with the straps, the insert still restricts flow and collects debris. 
   With the advancements in the art, it seems that coupling devices have become:
         (i) more complex in design,   (ii) more difficult to use,   (iii) more expensive, and   (iv) less streamlined.       

   And they still haven&#39;t solved the two main functional problems of:
         (v) leakage, and   (vi) flow restriction.       

   BRIEF SUMMARY OF INVENTION 
   It is an object of the present invention to solve the above identified problems by providing a simpler and more functional coupling device. Accordingly, several objects and advantages of the invention are to disclose a coupler which is:
         (i) simple in design   (ii) easy to use   (iii) inexpensive, and   (iv) streamlined and attractive       

   The proposed coupling device also solves the two main functional problems by providing an:
         (v) an effective sealing mechanism which won&#39;t swell or leak with age, and   (vi) less flow restriction through the coupling device.       

   A new and improved coupling device and method of engagement and disengagement is disclosed for coupling various tubular elongate members with improved efficiency. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention may be more readily described by reference to the accompanying drawings in which: 
       FIG. 1  is a perspective view of coupling device ready to connect two sections of hose. 
       FIG. 2  is a perspective view of two sections of hose coupled. 
       FIG. 3  is a cross-sectional view of the two end piece connectors coupled. 
       FIG. 4  is a cross-sectional view of the two hose ends coupled by means of coupling device. 
   

   REFERENCE NUMERALS IN DRAWINGS 
   
       
       Coupling device  1   
       First end piece connector  2   
       Second end piece connector  3   
       First tubular elongate member  4   
       Second tubular elongate member  5   
       Connection end of first tubular elongate member  6   
       Connection end of second tubular elongate member  7   
       Arrow of rotation  8   
       OD of first end piece connector  9   
       OD of first tubular elongate member  10   
       OD of second end piece connector  11   
       OD of second tubular elongate member  12   
       ID of first end piece connector  13   
       ID of first tubular elongate member  14   
       ID of second end piece connector  15   
       ID of second tubular elongate member  16   
       Length of first end piece connector  17   
       Length of second end piece connector  18   
       First end of first end piece connector  19   
       First end of second end piece connector  20   
       Second end of first end piece connector  21   
       Second end of second end piece connector  22   
       End piece threads of first end piece connector  23   
       End piece threads of second end piece connector  24   
       Midpoint of first end piece connector  25   
       Midpoint of second end piece connector  26   
       Circumferential grooves of first tubular elongate member  27   
       Circumferential grooves of second tubular elongate member  28   
       Coupling threads of first end piece connector  29   
       Coupling threads of second end piece connector  30   
       Tapered surface of first end piece connector  31   
       Tapered surface of second end piece connector  32   
     
  
   DETAILED DESCRIPTION 
   Referring more particularly to the drawings by characters of reference,  FIGS. 1 &amp; 2  disclose the preferred embodiment of the coupling device  1  of the present invention. 
     FIG. 1  shows first and second end piece connectors  2 ,  3  having the general form of thick-walled sections of tubing threadably engaged to first and second tubular elongate members  4 ,  5  respectively. 
     FIG. 2  shows the two sections of vacuum hoses coupled by means of the coupling device  1  of the present invention. This coupling is accomplished by means of a simple rotation of the two end piece connectors in the direction of the arrows  8 ; in the case of the preferred embodiment, clockwise. 
     FIG. 3  shows first and second end piece connectors  2 , and  3  comprising outer diameters (“OD”)  9  and  11 , inner diameters (“ID”)  13  and  15 , lengths  17  and  18 , first ends  19  and  20 , and second ends  21  and  22 , respectively. 
   In the preferred embodiment, end piece threads  23  and  24  line the interior surface of each end piece connector  2 ,  3  respectively and extend along the lengths  17 ,  18  of end piece connector  2 ,  3  respectively from their ends  19 ,  20  to their midpoints  25 ,  26 , respectively. 
   Coupling threads  29 , line the exterior surface of first end piece connector  2  and extend along the length  17  from about midpoint  25  to about three fourths of the distance from first end  19  to second end  21 . Coupling threads  30  line the interior surface of second end piece connector  3  and extend along the length  18  from about three fourths of the distance from first end  20  to second end  22  to about the second end  22  of end piece connector  3 . As shown in  FIG. 3 , coupling threads  29 ,  30  serve to lock end piece connector  2  and  3  together respectively, forming the coupled device  1  of the present invention. 
   Tapered surface  31  of first end piece connector  2 , lines the exterior surface forming the approximate final quarter of the length  17 , extending from about three fourths of the distance from first end  19  to second end  21  of end piece connector  2 . 
   Tapered surface  32  of second end piece connector  3 , lines the interior surface extending along the length  18  from about three fourths of the distance from first end  20  to second end  22  of end piece connector  3 . 
   As shown in  FIG. 3 , tapers  31 ,  32  serve to seal end piece connector  2  against end piece connector  3  respectively as coupling threads  29 ,  30  of end piece connector  2 ,  3  are engaged, thus forming a leak proof seal for the coupling device  1  of the present invention. Even with the coupling threads  29 ,  30  not completely threaded,  FIG. 3  shows the seal along tapers  31 ,  32  to still be in effect. 
     FIG. 4  shows first and second tubular elongate members  4  and  5  having the general form of sections of vacuum hoses comprising connection ends  6  and  7 , OD  10  and  12 , ID  14  and  16 , and circumferential grooves  27  and  28 , respectively. 
   In the preferred embodiment, end piece threads  23 ,  24  ( FIG. 3 ) of first and second end piece connectors  2 ,  3  respectively mate the circumferential grooves  27 ,  28  along the perimeter surfaces of respective first and second tubular elongate members  4 ,  5  and provide a secure engagement between respective first and second tubular elongate members  4 ,  5 . Alternatively, the end piece threads  23  and  24  could be omitted and replaced with smooth walls sized to that of the OD of tubular elongate members  4 ,  5 . This would allow end piece connectors  2 ,  3  to be fixedly glued to perimeter surface of each tubular elongate members  4 ,  5 . 
     FIG. 4  also shows that the narrowest ID of the coupling itself is not narrower than the IDs  14 ,  16  of the tubular elongate members  4 ,  5  themselves, thus there is no restriction of flow through the coupling device  1  of the present invention. 
   From the above description, a number of advantages of my coupling device  1  become evident:
         simple in design: As explained herein, the coupling device  1  of the present invention provides a simple and efficient design that utilizes only two parts—the first and second end piece connectors  2 ,  3 . There&#39;s no straps, inserts, tools or accessories needed for operation, and no seals to replace.   easy to use: Since there are no straps or buckles, there is less chance of hanging up on obstacles along the path of vacuum hose like steps, curbs, and corners. And since there&#39;s less likelihood of hose separation, then there&#39;s no aggravating and tiring ‘wedging,’ during the job.   inexpensive: My prototype end piece connectors  2 , 3  were machined from rugged stock irrigation tubing (source: Superion, Tacoma Wash.). They could also be injected molded from rugged any of several plastics such that price is comparable to existing coupling devices presently available.   streamlined and attractive. There&#39;s no bulky straps and less girth than the couplers presently available.       

   Functionally;
         an effective sealing mechanism: Rather than inserts or elastomeric seals, coupling threads  29 ,  30  are used to interlock end piece connectors  2 ,  3 . The combination of coupling threads  29 ,  30  plus tapers  31 ,  32  provide a reliable, leak proof seal effective even when the coupling threads  29 ,  30  are only partially engaged as is the case in  FIGS. 3 &amp; 4 . Surprisingly, the seal actually improves with exposure to the heated fluids typical of carpet cleaning solutions. The heat acts to help swell and seat the tapered seals and the vacuum helps to naturally draw the two end piece connectors  2 ,  3  closer together. The seal thus created along tapers  31 ,  32  of end piece connectors  2 ,  3  is further protected by the fact that end piece connector  3  envelopes the tapers  31 ,  32  and protects them from damage under normal working conditions.   less flow restriction: Since the narrowest ID  13 ,  15  of the coupling device  1  is no less than the IDs  14 ,  16  of the tubular elongate members  4 ,  5 , there is no narrowing through the coupling device  1  thus there is little or no flow restriction imposed by the coupling device  1 . Additionally, there are no projections to snag particulate as it passes through the coupling device  1 .       

   Operation: 
   User of coupling device  1  determines the correct end piece connectors  2 ,  3  to match the chosen tubular elongate members  4 ,  5 . In the case of carpet cleaning, vacuum hoses are typically used which have semi-rigid circumferential grooves  27 ,  28  ( FIG. 4 ) along their perimeter surfaces which mate well with the end piece threads  23 ,  24  of coupling device  1  of the present invention. A glue or silicone sealant may be used to fixedly secure the connection between circumferential grooves  27 ,  28  of tubular elongate members  4 ,  5  to mating end piece threads  23 ,  24  of end piece connectors  2 ,  3 , respectively although sealant is not necessary for operation. Alternatively, end piece connectors  2 ,  3  could be chosen which have no end piece threads  23 ,  24 , rather, they could be sized to fit the outer diameter of the tubular elongate members  4 ,  5  whereby they could be fixedly glued in place. 
   To engage the coupling device  1  of the present invention, the user simultaneously grasps end piece connector  2  in one hand between its midpoints  25  and first end  19  and grasps end piece connector  3  in the other hand between its midpoint  26  and its first end  20  then aligns tapered surface  31  of end piece connector  2  with mating tapered surface  32  of end piece connector  3 . Having thus contacted mating threads of each body, the user then simply rotates both end piece connectors  2 ,  3  in opposite directions relative to each other, in the case of the preferred embodiment, clockwise relative to each other as shown in ( FIG. 2 ) a minimal amount, typically about one-quarter of a revolution. Such rotation provides a simultaneous securement along the coupling threads  29 ,  30  of end piece connectors  2 ,  3  and a sealing engagement along the mating tapers  31 ,  32  respectively. Thus with a simple rotation, the two sections of vacuum hoses are coupled and sealed. 
   To disengage the coupling device  1 , the user simply grasps each end piece connectors  2 ,  3  as described above and rotates both end piece connectors  2 ,  3  in opposite directions, the direction or rotation being opposite that required for securement, in the case of the preferred embodiment, approximately one-quarter of a revolution counterclockwise, thus disengaging the two end piece connectors  2 ,  3  of coupling device  1 . 
   CONCLUSION, RAMIFICATIONS, SCOPE 
   Variously sized and shaped end piece connectors  2 ,  3  can be specifically manufactured or modified to fit various sized tubular elongate member  4 ,  5  in accordance with the coupling device  1  of the present invention. First and second end piece connectors  2 ,  3  may be threadably secured or the endpiece threads  23 ,  24  may be omitted and end piece connectors  2 ,  3  may be fixedly glued or otherwise secured to the outer surface of connection ends  6 ,  7  of first and second tubular elongate members  4 ,  5 . The relative shapes, lengths, styles, thread directions, and positioning of the coupling threads  29 ,  30  and tapers  31 ,  32  may be rearranged or reversed without effecting the essence of the ‘thread and taper’ engagement of the coupling device  1  without changing the scope of the invention. 
   The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, however, that other expedients known to those skilled in the art or disclosed herein, may be employed without departing from the spirit of the invention or the scope of the appended claims.