Patent Publication Number: US-2010115775-A1

Title: Extension cable and pipe processing device adapted thereto

Description:
RELATED APPLICATIONS 
     The present application is based on International Application Number PCT/EP2008/051057 filed Jan. 29, 2008, and claims priority from German Application Number 10 2007 013 502.7 filed Mar. 21, 2007, the disclosures of which are hereby incorporated by reference herein in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a flexible electric power extension cable and a matched pipe processing equipment. 
     BACKGROUND 
     In particular the present disclosure relates to pipe processing equipment in the form of a pipe cutting equipment such as is known from the German patent document DE 103 52 890 A1 (=US 2005/0097752 A1). Similar pipe equipment is known from the Swiss patent document 372202 and the German patent document DE 101 34 269 B4. Such equipment contains a clamp to affix a pipe segment to be cut off and a cutting system to cut the clamped pipe. The cutting system is supported at the clamp so as to be rotatable about a pipe longitudinal axis defined by said clamp. The cutting system contains a tool holder to hold a cutting tool, for instance a circular saw blade, further an electric motor to drive into rotation the said tool holder together with the tool affixed in it. The cutting system comprises a lever arm projecting for instance radially to said pipe&#39;s axis of rotation and designed to act as a grip or be fitted with a handlebar to rotate said lever arm about said pipe&#39;s axis of rotation. The electric motor may be received in the lever arm. Conventionally an electric power cable is connected to the cutting system to feed electric power to the electric motor. One end of said cable is situated in the cutting system, for instance in said lever arm, The other cable end away from the cutting system is plugged into a cable outlet socket, hereafter just outlet, by means of a plug matching the conventional outlets of the public power company and accordingly fits into such outlets to set up connection between the outside power line and the cable. Said power cable contains at least two conductors. 
     The cutting element may be a circular saw blade or a grinding cutting wheel. 
     The present disclosure also applies to pipe cutting systems disclosed in the German patent document DE 100 20 393 A1. Moreover it is applicable to pipe end processing means known for instance form the patent documents DE 197 26 498 A1, DE 100 14 578 A1 and DE 102 16 787 A1. Again it relates to combined; pipe cutting systems and pipe end processing means illustratively disclosed In the German patent document DE 196 03 361 A1. The latter machinery is used to cutting pipes and to bevel pipe ends in particular of thin-walled metal pipes. 
     Moreover the disclosure also relates to pipe cutting systems illustratively known from the patent documents U.S. Pat. No. 4,890,385 and U.S. Pat. No. 6,065,212. These contain a motor driving a rotary unit rotatably resting in a housing and supporting the pipe cutting tool. Said motor also displaces the cutting tool radially toward the pipe to be cut off. The housing and the rotary unit are fitted with a radial access aperture through which the pipe cutting system ca be radially displaced against a pipe to be cut. 
     In many countries the electrical power line outlet boxes are different. Consequently the pipe-processing equipment cable plugs designed to connect with said line outlets most of the time only fit into the power outlets of one country but not in any of the others. As a result the manufacturers of pipe processing means must manufacture a plurality of such different means each for a different country, and keep such in stock, and, when shipping them, take into account the particular power outlet of the particular country. 
     Pipe processing means such as pipe cutting systems and/or pipe-end processing devices are exposed to rough operational and environmental conditions. They are used in pipe processing shops and in rudimentary buildings. Consequently the flexible electrical cables of the pipe processing means are frequently damaged and require being exchanged. Such changing of cables entails opening the processing apparatus and connecting the new conductors of a new cable inside the pipe processing apparatus, further appropriately tension/stress-relieving said cable in said apparatus. For reasons of safety, a cable should not be exchanged by the pipe processing operator but instead by a qualified electrician. In other words, the pipe processing apparatus must be delivered to an electrical shop and then be picked up there later. 
     The pipe processing apparatus&#39; cable sustains damage not only by being squeezed by persons standing on it or by metal objects dropping on it, but also by forces stretching it and possibly tearing it apart, or nearly so, due to somebody stepping on it or an object being dropped on it. 
     Another source of damage is the twisting of such a cable during use while not being entirely twist-relieved subsequently, but instead being stretched. 
     There is a need to improve the handling of pipe processing equipment. 
     SUMMARY 
     This problem is solved by a flexible electric power extension cable for pipe processing equipment with a plug affixed to it and matching a cable connecting element of the extension cable. 
     Thus, a single design of the pipe processing equipment can be used in more than one countries. Merely different extension cables are required. If the extension cable should be or become defective, said equipment remains ready for operation. It need not be opened. Accordingly operational reliability is increased. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically shows a flexible electrical power cable in combination with a matched pipe processing equipment, 
         FIG. 2  is a perspective of the extension cable of  FIG. 1 , 
         FIG. 3  is a perspective of a female cable connector part at the rear end of the extension cable, 
         FIG. 4  is a perspective of a male cable connector part matching the female cable connector part of  FIG. 3  and jointly with it able to set up electrical connection between them, 
         FIG. 5  is the male cable connector part of  FIG. 4  configured at the external end of a flexible power cable running into the housing of a lever arm of a cutting system of  FIG. 6 , and 
         FIG. 6  is a perspective of a pipe cutting system of which part is shown in  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION 
     The flexible electric power extension cable  2  shown in  FIGS. 1 ,  2  and  3  contains at least two conductors. The extension cable  2  comprises a front cable segment  2 - 1  and a rear cable segment  2 - 2 . The two cable segments  2 - 1  and  2 - 2  are connected to each other by a rotary junction  4  allowing rotating said segments  2 - 1  and  2 - 2  about their longitudinal axis and relative to each other. 
     A plug  6  for at least two conductors is connected to the front end of the front cable segment  2 - 1 . A female cable connector part  8  is connected to the rear end of the rear cable segment  2 - 2 . 
     The cable plug  6  is a power-line accessing plug designed to be plugged into a power line&#39;s outlet to effect electrical connection. 
     The design of the female cable connector part  8  is different from the geometry of the power line outlets whereby the cable plug  6  does not fit into the female cable connector part  8  and therefore electrical connection between them is precluded. Electrical connection with the female cable connector part  8  is possible only with a matching cable plug or with a matching plug affixed to a pipe processing equipment. 
       FIG. 3  shows one of many possible female cable connector parts  8 . It may comprise a central, electrically insulating connection dowel  10  containing at least two jacks  12 ,  13 , and/or  14  of which the rearward-pointing ends are recessed in said dowel, said jacks therefore not protruding out of the dowel  10 , the number of jacks corresponding to the number of conductors of the extension cable  2 . An annular spacing  18  open toward the rear end face is subtended between the outer circumference of the connection dowel  10  and a housing ring  16  enclosing said dowel while radially spaced from it. 
     The female cable connector part  8  of  FIG. 3  may be engaged by a plug mounted in fixed manner on the pipe processing equipment or by a second male cable connector part  20  shown in  FIG. 4  to set up electrical connection, said male part  20  being fitted with contact pins  22 ,  23  and/or  24  aligned with the jacks  12 ,  13 , and  14 , and also being fitted with an electrically insulating muff  26  enclosing all engaging pins  22 ,  23  and  24  and fitting into the annular spacing  18  of the female cable connector part  8  of  FIG. 3 . In this manner the female cable connector part  8  can be made to engage, i.e. to make electrical contact with, the male cable connector part  20  of  FIG. 4  or a stationary plug designed in the manner of the male cable connector part  20  to set up electrical connection. 
     The number of jacks  12 ,  13 ,  14  and the number of the matching pins  22 ,  23 ,  24  is at least two, though it may be another number, for instance 3, 5, 6 or more. Such a number may be higher than required electrically, for instance when the said female and male parts or other connection elements might be more economical than for a lower number. 
     The rear cable segment  2 - 2  is constituted over at least part of its length by a coil  30 , so that this portion of the segment  2 - 2  resembles a helical spring and may expand elastically in the longitudinal direction of said rear segment. 
     The pipe processing equipment  40  is schematically shown in  FIG. 1 . It may be a pipe cutting system or a pipe-end processing apparatus or a combined pipe cutting system and pipe-end processing apparatus. It includes an electric motor  42  which directly or by means of a gear unit  44  drives into rotation a tool support  46  and a tool  48  affixed to it. The pipe processing equipment  40  may be fitted with a flexible electric cable  50  to feed power to the said motor  42 , this cable being connectable within a housing  52  of said pipe processing equipment to the electric motor  42  by means of an omitted switch. This connection may be implemented either directly or through a storage battery. A male cable connector part  20  is connected to the external end of the external cable portion  54  and matches the female cable connector part  8  of the extension cable  2  to allow mutual electrical connection. The external male cable connector part may be said part  20  discussed in relation to  FIG. 4 . 
     Instead of an external male cable connector part  20  matching the female cable connector part  8  of the extension cable  2 , a fixed electric plug matched to the female cable connector part  8  of said cable might be mounted on the pipe affixation device, for instance on the housing  52 , so as to engage these parts to implement electrical connection. 
     To prevent the external male cable connector part  20  of  FIGS. 1 through 4  from lying on the ground during operation of the pipe processing equipment, in which case it might be damaged, the length of the external cable portion  54  from the housing  52  to the external male cable connector part  20  preferably shall be between 5 cm and at most 60 cm, the minimum length preferably being 10 cm and the maximum length preferably being 40 or 30 Cm. 
     In order to prevent accidentally separating from each other the female cable connector part  8  and the external male cable connector part  20 , or in lieu of latter a stationary plug on the pipe processing equipment  40 , they are preferably fitted with a locking element  8 - 1  respectively  20 - 1 , for instance mutually meshing threads as indicated schematically in  FIG. 1 , or with a locking lever and a locking protrusion that may be mechanically interlocked and each requiring separation from one another before the female cable connector part  8  can be separated from the external male cable connector part  20  or from a matched stationary plug on the pipe processing equipment  40 . As regards a preferred embodiment mode, the locking elements  8 - 1  and  20 - 1  are designed to constitute a bayonet lock. 
     As schematically shown in  FIG. 1 , the rotary junction  4  contains mutually locking elements  4 - 1  and  4 - 2  rotatable about the cable longitudinal axis. The locking element  4 - 1  contains the rear end conductors of the front cable segment  2 - 1 , two of said conductors, of which the elements  62  and  63  are shown, making contact with their terminals  64  respectively  66  that in turn slide on contacts  78  respectively  80  of the other locking element  4 - 2 . These further contacts  78  and  80  are connected at the front end of the rear cable segment  2 - 2  to the conductors  82  respectively  83  (or more) of the rear cable segment  2 - 2 . 
       FIG. 5  shows a lever arm  90  for the pipe processing equipment  40  of  FIG. 1 . This lever arm  90  illustratively may contain the electric motor  42  and be fitted with one or two handlebars  91  and/or  92 . The outer cable portion  54  together with the external male cable connector part  20  at the external end of the lever arm runs through a cable sheath  93  and a housing aperture  94  into a housing element  95  of said lever arm. 
       FIG. 6  illustrates a detailed embodiment mode of the pipe processing equipment  40 . Illustratively it contains a pipe clamp  100  for instance in the form of a vise to clamp a pipe being processed and defines a longitudinal axis of such a pipe. A rotary unit  102  rests on said clamp  100  and is rotatable about the longitudinal pipe axis  101 . A slider  104  is configured at the clamp  100  and rotates about the said longitudinal pipe axis. The slider  104  supports an omitted, rotatable tool holder for a pipe processing tool  106 , for instance a cutting tool such as a circular saw blade or a grinding cutting disk. 
     A pipe-end processing apparatus also might be used in lieu of a pipe cutting tool  106 . 
     The lever arm  90  runs transversely to the longitudinal pipe axis  101 , for instance radially to it. 
       FIG. 6  shows the housing access aperture  94  for the hookup cable  50  of the pipe processing equipment  40 . Instead of a power cable  50 , an electric plug  108  might be mounted in stationary manner at the pipe processing equipment  40 , in particular at its lever arm  90 , said plug being designed in a manner that it cannot enter the power line electric outlets but instead is matched to the cable female cable connector part  8  of the power extension cable  2  to allow connecting it with the female cable connector part  8  to set up electrical connection. In this instance said housing aperture  94  is not needed. Illustratively the plug  108  may be mounted at the site previously assumed by the said aperture  94 . 
     An ON/OFF switch  110  turning the motor  42  on/off may be mounted on the lever arm  90 . Also an angular-speed regulator  112  may be fitted to the lever arm  90  to adjust motor speed. Again said lever arm  90  may be fitted with an electronics  114  to keep constant the motor speed set at the regulator  112  regardless of the load on the tool  106 . 
     Instead of one or more handlebars  91 ,  92  being affixed to the lever arm  90 , said lever arm per se may be designed as a grip.