Patent Publication Number: US-7896398-B2

Title: Pipe handle and cleaning device using the same

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a pipe handle formed by coupling a plurality of pipes and to a cleaning device having the pipe handle and a head. 
     2. Description of the Related Art 
     There have been known cleaning devices composed of a pipe handle and a head connected to one end of the pipe handle. Cleaning devices of this type are typically used with a disposable cleaning sheet (e.g., a wiper of nonwoven fabric) attached to the head. When used for cleaning the house floor or the like, the pipe handle need be so long that the head can slide on the floor surface with a grip (the other end of the pipe handle) being held by hand. 
     Japanese Unexamined Patent Publication Nos. 2002-005135 and 2002-081420 disclose pipe handles which are constructed by coupling a plurality of pipes to have a certain length. 
     Firstly, they disclose coupling between a larger diameter pipe and a smaller diameter pipe, wherein one end of the smaller diameter pipe fits in one end of the larger diameter pipe. 
     In this case, however, the smaller diameter pipe may be too thin to withstand a bending stress during use, particularly when the pipe handle is constructed of three or more pipes. The bending stress exerted on such a long object is proportional to the bending moment and is inversely proportional to the modulus of section, but in case where the pipe wall thickness is constant, the modulus of section decreases as the outside/inside diameter decreases. Therefore, the use of the smaller diameter pipe may increase the bending stress due to the bending moment during cleaning, which lowers the bending strength. 
     Secondly, they disclose that a male coupling (or male side end part) of one pipe diametrically contracts toward a distal end to have two-stage tapered outer surface, a proximal second tapered outer surface having a steeper gradient than a distal first tapered outer surface, and a female coupling (or female side end part) of the other pipe has a tapered inner surface whose gradient is equal to that of the first tapered outer surface so that the two pipes can be coupled together by fitting the tapered inner surface of the female coupling over the first tapered outer surface of the male coupling. 
     In this case, however, since the pipe has to be circumferentially contracted to produce the first and second tapered outer surfaces, the pipe wall thickness tends to vary in the contracted portion, which makes it difficult to hold dimensions of the first tapered outer surface to close tolerance. If the dimensions of the first tapered outer surface cannot be held to close tolerance, insertion of the male coupling into the female coupling will be difficult due to tightness or the male coupling will wobble within the female coupling due to looseness. In addition, such contracting, which is typically performed by clamping and deforming a pipe end between rolls, requires an expensive processing equipment for holding the dimensions to close tolerance and requires some experience, which also results in high cost. 
     Moreover, since the first tapered outer surface, which is formed by diametrically contracting the male side end part, has a relatively small diameter, the strength against bending moment decreases as set forth above. Furthermore, the first tapered outer surface formed by diametrically contracting the pipe tends to fatigue due to residual stress. Therefore, if the bending stress concentrates in the connection between the pipes during cleaning, bending or cracking tends to occur in the first tapered outer surface. 
     Japanese Unexamined Patent Publication No. 2002-005135 further discloses a sleeve which is to be located around the male and female couplings of the two pipes. Coupling between the two pipes can be maintained by fitting an engaging projection, which is formed on an inner surface of the sleeve, into both an engaging hole of the male coupling and an engaging hole of the female coupling. 
     In order to fit the engaging projection into the engaging holes, the sleeve need be slid on the pipe after coupling. However, as the sleeve is slid on the pipe, the engaging projection also comes into contact with the pipe to resist sliding. In addition, it is impossible to visually confirm whether the engaging projection has fitted in the engaging holes from the outside. 
     SUMMARY OF THE INVENTION 
     The present invention has been developed to solve the problems in the prior art set forth above and has an object to provide a pipe handle which enables high precision coupling with sufficient strength to withstand bending stress during use and a cleaning device using the same. 
     According to the present invention, there is provided a pipe handle comprising first and second pipes which are engaged together with a male coupling of the second pipe fitted into a female coupling of the first pipe, 
     the first pipe having a larger inside diameter in the female coupling than in a main body adjacent to the female coupling, the second pipe having a continuous outer surface without any step between the male coupling and a main body adjacent to the male coupling, the main body of the first pipe and the main body of the second pipe having an equal or almost equal outside diameter. 
     The main bodies of the first and second pipes constituting the pipe handle according to the present invention may have the same outside/inside diameter. In addition, the female coupling may be formed by diametrically expanding the first pipe, which results in high precision diameter as compared with the case where a male coupling is formed by diametrically contracting a pipe. Moreover, both the male and female couplings may have sufficient strength to withstand bending moment. 
     According to one embodiment of the present invention, the continuous outer surface of the second pipe may have a constant outside diameter. In this case, the male coupling may be formed without deforming the second pipe at all. 
     Alternatively, the male coupling of the second pipe may have a tapered outer surface whose outside diameter gradually decreases from a boundary between the main body and the male coupling to a distal end of the male coupling and an angle formed between the tapered outer surface of the male coupling and an outer surface of the main body may be equal to or less than 0°50′ (0 degrees 50 minutes). The tapered outer surface facilitates insertion of the male coupling into the female coupling. In addition, if the gradient of tapered outer surface is equal to or less than 0°50′, the male coupling can be effectively prevented from wobbling due to looseness. 
     In this embodiment, furthermore, the female coupling of the first pipe may have a tapered inner surface whose inside diameter gradually increases toward a distal end of the female coupling and an angle formed between the tapered inner surface of the female coupling and an inner surface of the main body may be equal to or less than 0°50′. This further facilitates insertion of the male coupling into the female coupling and prevents the male coupling from wobbling due to looseness. 
     According to one embodiment of the present invention, the first pipe may have an intermediate part which provides a step between an inner surface of the female coupling and an inner surface of the main body, the intermediate part may have a tapered inner surface whose inside diameter gradually increases from the inner surface of the main body to the inner surface of the female coupling, and an angle formed between the tapered inner surface of the intermediate part and the inner surface of the main body may be larger than an angle formed between the inner surface of the female coupling and the inner surface of the main body. The intermediate part, whose tapered inner surface has a steeper gradient than that of the female coupling, may function as a stopper because the distal end of the male coupling can abut against the inner surface of the intermediate part when the male coupling is inserted into the female coupling. 
     Preferably, an engaging member, which is adapted to fit in both an engaging hole of the female coupling and an engaging hole of the male coupling for maintaining coupling between the first and second pipes, is provided inside the male coupling of the second pipe. The engaging member may be fitted in the engaging hole of the female coupling only by inserting the male coupling into the female coupling. The engagement may be visually confirmed from the outside. 
     According to the present invention, there is also provided a cleaning device comprising the above-mentioned pipe handle and a head connected to one end of the pipe handle for attachment of a cleaning sheet. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be understood more fully from the detailed description given hereinafter and from the accompanying drawings of the preferred embodiment of the present invention, which, however, should not be taken to limit the invention, but are for explanation and understanding only. 
       In the drawings: 
         FIG. 1  is a perspective view of a cleaning device employing a pipe handle according to one embodiment of the present invention; 
         FIG. 2  is an exploded perspective view showing a connection of the pipe handle according to an embodiment of the invention; 
         FIG. 3(A)  is a sectional view of a female coupling of a first pipe and  FIG. 3(B)  is a sectional view of a male coupling of a second pipe according to an embodiment of the invention; and 
         FIG. 4  is a sectional view showing a state where the male coupling fits in the female coupling according to an embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will be discussed hereinafter in detail in terms of the preferred embodiment according to the present invention with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be obvious, however, to those skilled in the art that the present invention may be practiced without these specific details. In other instance, well-known structures are not shown in detail in order to avoid unnecessary obscuring of the present invention. 
       FIG. 1  is a perspective view of a cleaning device employing a pipe handle according to one embodiment of the present invention;  FIG. 2  is an exploded perspective view showing a connection of the pipe handle;  FIG. 3(A)  is a sectional view of a female coupling of a first pipe;  FIG. 3(B)  is a sectional view of a male coupling of a second pipe; and  FIG. 4  is a sectional view showing a state where the male coupling fits in the female coupling. 
       FIG. 1  shows a cleaning device  1  which is suitable for cleaning the house floor and composed of a pipe handle  2 , a head  3  connected to a front end of the pipe handle  2  and a grip  16  attached to a rear end of the pipe handle  2 . 
     The pipe handle  2  may be constructed by coupling four short pipes, i.e., a rear-side end pipe  4 , a rear-side intermediate pipe  5 , a front-side intermediate pipe  6  and a front-side end pipe  7 . In  FIG. 1 , the rear-side end pipe  4  and the rear-side intermediate pipe  5  are coupled together at a connection  8 , the rear-side intermediate pipe  5  and the front-side intermediate pipe  6  are coupled together at a connection  9 , and the front-side intermediate pipe  6  and the front-side end pipe  7  are coupled together at a connection  10 . The head  3 , which is connected to the front end of the long pipe handle  2  constructed by coupling these pipes, can be slid on a floor surface by holding the grip  16 . When not in use, the cleaning device  1  may be stored compactly by uncoupling the pipes. 
     The head  3  may be rectangular in plan configuration and may have a top face which is centrally connected to the front end of the front-side end pipe  7  through a universal joint  11 . To the head  3 , a cleaning sheet  12  may be attached for cleaning. The cleaning sheet  12  may be a disposable wiper constructed mainly of a nonwoven fabric and capable of absorbing liquid. The cleaning sheet  12  may be laid on a bottom face of the head  3  and partially folded back against the top face of the head  3  and detachably fixed on the top face of the head  3  by fixing means (not shown). 
     A holder  13  may be fixed on the front-side intermediate pipe  6  with an opening directed upward so that a container  14  filled with liquid can be put in the holder  13 . The grip  16  has a push button  15 . By pushing the push bottom  15 , a valve of the holder  13  may be opened to let the liquid inside the container  14  flow down a tube passing through the front-side intermediate pipe  6  and the front-side end pipe  7  and the liquid may be squirted from a nozzle of the head  3  and applied to the floor surface in front of the head  3 . 
     The grip  16  may be made of a synthetic resin and secured on the rear end of the rear-side end pipe  4 . 
     At the connections  8 ,  9 ,  10 , two pipes may be coupled in the same manner. Therefore, only the structure of the connection  8  where the rear-side end pipe  4  and the rear-side intermediate pipe  5  are coupled will be described hereinbelow with reference to  FIGS. 2 to 4 . In the embodiment of  FIGS. 2 to 4 , the rear-side end pipe  4  has a female coupling and is called “first pipe” and the rear-side intermediate pipe  5  has a male coupling and is called “second pipe”. Alternatively, the rear-side end pipe  4  may have a male coupling and be called “second pipe” and the rear-side intermediate pipe  5  may have a female coupling and be called “first pipe”. This relationship is also true in the connections  9  and  10 . 
     The first pipe  4  of  FIG. 3(A)  and the second pipe  5  of  FIG. 3(B)  may be cylinders of aluminum or aluminum alloy, whose inner and outer surfaces are both circular in section taken on a plane perpendicular to the pipe axis. Alternatively, the first pipe  4  and the second pipe  5  may be made of copper alloy, brass alloy, stainless steel, etc. These pipes are preferably made of any one of the above-mentioned metals from the viewpoint of strength, although they may also be made of a synthetic resin. 
     As shown in  FIG. 3(A) , the first pipe  4  has a main body  21  and a female coupling  22  projecting forward from a front end of the main body  21  to have a length L 1 . Between the main body  21  and the female coupling  22 , there may be provided an intermediate part  23  for forming a step between an inner surface  21   b  of the main body  21  and an inner surface  22   b  of the female coupling  22 . In the main body  21 , an outer surface  21   a  has an outside diameter D 1  and the inner surface  21   b  has an inside diameter D 2 . The main body  21  has a wall thickness T 1 . The outside diameter D 1  may be about 10 to 50 mm and the wall thickness T 1  may be about 1 to 5 mm. 
     The female coupling  22  and the intermediate part  23  may be formed by diametrically expanding a pipe material having the same diameter as the main body  21 . The female coupling  22  has an inside diameter D 3  at a boundary  24  between the female coupling  22  and the intermediate part  23  and an inside diameter D 4  at a distal end  25 , wherein the inside diameter D 4  may be equal to or slightly larger than the inside diameter D 3 . In the case where D 4 &gt;D 3 , an angle θ 1  between the inner surface  22   b  of the female coupling  22  and the inner surface  21   b  of the main body  21  is equal to or less than 0 degrees 50 minutes in the sectional view of  FIG. 3(A) . That is, 0°≦θ1≦0°50′. 
     In the intermediate part  23 , the inside diameter gradually increases from a boundary  26  between the intermediate part  23  and the main body  21  to the boundary  24 . That is, the intermediate part  23  has a tapered inner surface  23   b . An angle θ 2  between the inner surface  23   b  of the intermediate part  23  and the inner surface  21   b  of the main body  21  is sufficiently larger than the angle θ 1  and in the range of 10° to less than 90°. 
     As shown in  FIG. 3(B) , the second pipe  5  has a main body  31  and a male coupling  32  projecting rearward from a rear end of the main body  31  to have a length L 2 . The length L 2  of the male coupling  32  may be equal to the length L 1  of the female coupling  22  or shorter than the length L 1  by about 0.5 to 5 mm. 
     The main body  31  has an outer surface  31   a , whose outside diameter D 5  is equal to or almost equal to the outside diameter D 1  of the main body  21  of the first pipe  4 , and an inner surface  31   b , whose inside diameter D 6  is equal to or almost equal to the inside diameter D 2  of the main body  21  of the first pipe  4 . The main body  31  has a wall thickness T 2 , which is equal to or almost equal to the wall thickness T 1  of the main body  21  of the first pipe  4 . Accordingly, the second pipe  5  may be formed of a pipe material having the same nominal size as that used for the first pipe  4 . 
     The male coupling  32  has an outer surface  32   a . The outer surface  32   a  has an outside diameter D 7  at a boundary  33  between the male coupling  32  and the main body  31  and an outside diameter D 8  at a distal end  34 . According to a first embodiment, the outside diameter D 7  may be equal to the outside diameter D 8  and also equal to the outside diameter D 5  of the main body  31 . That is, the outer surface  31   a  of the main body  31  and the outer surface  32   a  of the male coupling  32  may have a constant outside diameter without processing the male coupling  32  to vary the diameter. 
     According to a second embodiment, the outside diameter D 7  at the boundary  33  may be equal to the outside diameter D 5  but the outside diameter D 8  at the distal end  34  may be slightly smaller than the outside diameter D 7 . This may be achieved by diametrically contracting the pipe material or polishing the outside surface  32   a . More specifically, the outside surface  32   a  of the male coupling  32  may be so tapered that the outside diameter gradually decreases toward the distal end  34 . In this case, an angle θ 3  between the outside surface  31   a  of the main body  31  and the outside surface  32   a  of the male coupling  32  is equal to or less than 0°50′ in the sectional view of  FIG. 3(B) . According to the first and second embodiments, therefore, 0°≦θ3≦0°50′. In either embodiment, there is no step between the outer surface  31   a  of the main body  31  and the outer surface  32   a  of the male coupling  32 . 
     When the outer surface  32   a  of the male coupling  32  has a constant diameter according to the first embodiment, the angle θ 1  of the female coupling  22  is preferably 0° or almost 0°. This prevents wobbling of the first and second pipes  4 ,  5  at the connection  8 . 
     When the outer surface  32   a  of the male coupling  32  is tapered according to the second embodiment, on the other hand, the angle θ 1  of the female coupling  22  may fall within the range between 0° and 0°50′. In this case, however, the angle θ 3  of the outer surface  32   a  of the male coupling  32  is preferably equal to or almost equal to the angle θ 1  of the inner surface  22   b  of the female coupling  22 . Most preferably, the angle θ 1  is equal to the angle θ 3 . 
     By minimizing the angular difference between the outer surface  32   a  of the male coupling  32  and the inner surface  22   b  of the female coupling  22  with respect to the pipe axis, as set forth above, the outer surface  32   a  of the male coupling  32  can fit with minimum clearance against the inner surface  22   b  of the female coupling  22  to thereby prevent wobbling at the connection  8 . 
     In order that the male coupling  32  will closely fit in the female coupling  22 , as set forth above, the outside diameter D 8  at the distal end  34  of the male coupling  32  is preferably equal to or slightly smaller than the inside diameter D 3  at the boundary  24  of the first pipe  4 . Also, the outside diameter D 7  at the boundary  33  of the second pipe  5  is preferably equal to or slightly smaller than the inside diameter D 4  at the distal end  25  of the female coupling  22 . 
     As shown in  FIG. 3(A) , the female coupling  22  may have an engaging hole  22   c , which is spaced a distance L 3  apart from the boundary  24  toward the distal end  25 , and the male coupling  32  may have an engaging hole  32   c , which is spaced the same distance L 3  apart from the distal end  34  toward the boundary  33 . The engaging hole  22   c  and the engaging hole  32   c  may have the same opening diameter. 
     Inside the male coupling  32  of the second pipe  5 , an engaging member  41  may be provided as shown in  FIG. 4 . The engaging member  41  may be made of a synthetic resin material or a resiliently deformable metal material and may be integrally formed with an engaging projection  43  on an outer surface of a resiliently deformable part  42 . The engaging projection  43  may have a slope  43   a  declining toward the distal end  34  of the male coupling  32  to have a minimum height equal to or greater than the sum of the wall thickness T 1  and the wall thickness T 2 . 
     When the first pipe  4  and the second pipe  5  are separated from each other, as shown in  FIG. 2 , the slope  43   a  of the engaging projection  43 , which is fitted in the engaging hole  32   c  of the male coupling  32  from the inside, projects from the outer surface  32   a  of the male coupling  32 . 
     When the male coupling  32  of the second pipe  5  is inserted into the female coupling  22  of the first pipe  4 , the resiliently deformable part  42  may be deformed toward the inside of the male coupling  32  by contact of the slope  43   a  of the engaging projection  43  with the distal end  25  of the female coupling  22  so that the engaging projection  43  may slide on the inner surface  22   b  of the female coupling  22 . The extent of insertion of the male coupling  32  may be limited by contact of the distal end  34  of the male coupling  32  with the inner surface  23   b  of the intermediate part  23  of the first pipe  4  or the boundary  24 . After insertion, the resiliently deformable part  42  may recover to the original state when the engaging projection  43  is aligned with the engaging hole  22   c  of the female coupling  22 , so that the engaging projection  43  fits in the engaging hole  22   c  of the female coupling  22 , as shown in  FIG. 4 . Thus, coupling between the first pipe  4  and the second pipe  5  can be maintained. 
     It should be noted that the engaging projection  43  may be disengaged from the engaging hole  22   c  by depressing the engaging projection  43 , which projects from the outer surface of the female coupling  22  in the engaging state of  FIG. 4 . Thus, the first pipe  4  and the second pipe  5  may be separated from each other. 
     In the connections  8 ,  9 ,  10 , as has been described hereinabove, the first pipe  4 , whose female coupling  22  is formed by diametrically expanding the pipe material, does not have a portion having a smaller diameter than the main body  21  and the second pipe  5 , whose outer surface is continuous without any step between the male coupling  32  and the main body  31 , has a constant or almost constant diameter. Therefore, the connections  8 ,  9 ,  10  are prevented from being subjected to excess stress due to bending moment and are increased in strength against the bending moment. Thus, even if the cleaning sheet  12  attached to the head  3  is strongly pressed against the floor surface by holding the grip  16  of  FIG. 1  in hand, deformation of the pipe handle  2  at the connections  8 ,  9 ,  10  can be effectively prevented. 
     In addition, the outer surface  32   a  of the male coupling  32  of the second pipe  5  is not processed to vary the diameter, or even if the outer surface  32   a  is tapered, its gradient is extremely slight. Therefore, the size and shape of the outer surface  32   a  of the male coupling  32  do not vary widely. Furthermore, since the female coupling  22  of the first pipe  4  is formed by diametrically expanding the pipe material, the size and shape of the inner surface  22   b  do not vary widely. Hence, when the male coupling  32  is inserted into the female coupling  22 , as shown in  FIG. 4 , the outer surface  32   a  can fit with minimum clearance against the inner surface  22   b  to thereby prevent wobbling at the connections  8 ,  9 ,  10 . 
     The engaging member  41 , which is provided inside the male coupling  32 , can be easily fitted in the engaging hole  22   c  of the female coupling  22  only by inserting the male coupling  32  into the female coupling  22  and aligning the engaging hole  22   c  with the engaging hole  32   c . This arrangement also facilitates disengagement of the engaging member  41  from the engaging hole  22   c.    
     The pipe handle  2  may have a constant outside diameter except for the connections  8 ,  9 ,  10 , which results in improving the appearance and providing an almost uniform strength throughout the length of the pipe handle  2 . 
     Although the present invention has been illustrated and described with respect to exemplary embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omission and additions may be made therein and thereto, without departing from the spirit and scope of the present invention. For example, the cleaning device may be adapted for cleaning a ceiling or wall. The number of pipes constituting the pipe handle may be two or three or five or more. The section of the pipe may be oval or elliptical, instead of circular. 
     Therefore, the present invention should not be understood as limited to the specific embodiments set out above but should be understood to include all possible embodiments which can be embodied within a scope encompassed and equivalent thereof with respect to the feature set out in the appended claims.