Abstract:
An assembly for actuating a pipe expander, the assembly comprising a first actuator, arranged to engage a pipe expander head and actuate the same a second actuator, spaced apart from the first actuator and operatively engaged therewith such that operation of the second actuator effects operation of the first actuator to actuate the pipe expander head.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a U.S. national phase pursuant to 35 U.S.C. §371, of PCT/AU2008/000900, filed Jun. 20, 2008, which claims priority to Australian Patent Application No. 2007903382 filed Jun. 22, 2007. The entire contents of the aforementioned patent applications are incorporated herein by this reference. 
     BACKGROUND OF THE INVENTION 
     This invention relates to pipe expanders. When joining lengths of pipe, a tool known as a pipe expander is utilised to enlarge the diameter of the ends of one of the pipes to be joined. The pipe expander takes the form of a main body portion and a number of interchangeable expander heads to suit pipes of various diameters. The main body portion includes two large handles which are squeezed together to effect movement of an internal mechanism which in turn acts to cause movement of the expander head which is screw fitted to the main body portion. The expander head is tapered. Upon insertion into a pipe, the expander head is pushed inward along the pipe by mechanical means such as a shaft. This moves the expander head into the end of the pipe to be expanded. The tapered shape of the expander head means the pipe is forced outwardly in the axial direction. The steel or other pipe is thus expanded. 
     When working in confined areas, such as near to a wall or floor or on a building site, it is sometimes difficult, or impossible, to gain access to the pipe in order to bring the expander head into engagement with the pipe end to be enlarged. 
     SUMMARY OF THE INVENTION 
     In a first aspect, disclosed is an assembly for actuating a pipe expander, the assembly comprising a first actuator, arranged to engage a pipe expander head and actuate the same; and a second actuator, spaced apart from the first actuator and operatively engaged therewith such that operation of the second actuator effects operation of the first actuator to actuate the pipe expander head. 
     In one form the first actuator and second actuator are connected by a conduit. In one form the first actuator and second actuator are connected by a fluid tight conduit. In one form the fluid tight conduit is flexible. 
     In one form the first actuator comprises a first piston located within a first cylinder and adapted such that a movement of the first piston with respect to the first cylinder actuates the pipe expander head. 
     In one form the second actuator comprises a second piston located within a second cylinder. 
     In one form the first actuator comprises a first piston located within a first cylinder and adapted such that a movement of the first piston with respect to the first cylinder actuates the pipe expander head and the second actuator comprises a second piston located within a second cylinder and wherein the first actuator and second actuator are operatively engaged such that movement of the second piston with respect to the second cylinder effects movement of the first piston with respect to the first cylinder. 
     In one form the second actuator is adapted to operatively engage with a pipe expander body such that actuation of the pipe expander causes movement of the second piston with respect to the second cylinder. 
     In one form the first piston is moveable between a retracted position in which it is contained in the cylinder and an extended position in which is extends beyond the cylinder. In one form the first piston actuates the pipe expander head when in the extended position. 
     It can be seen that use of the assembly to actuate a pipe expander allows a user to expand a pipe which is in a difficult position while remaining some distance from the pipe. This allows for use of a pipe expander in difficult spaces with limited access without requiring significant damage to the structures in which the pipes are positioned. 
     In a second aspect, disclosed is an extension for a pipe expander, the extension including a first actuator arranged to receive a pipe expander head, the first actuator including a first chamber and piston; a second actuator arranged to fit to a pipe expander, the second actuator including a second chamber and piston; and a fluid tight conduit which joins the first and second chambers. 
     In one form the conduit is flexible. 
     In a third aspect, disclosed is a method of using a pipe expander comprising engaging the pipe expander head with a first piston and cylinder assembly such that movement of the first piston with respect to the first cylinder actuates the pipe expander head and initiating movement of the first piston with respect to the first cylinder. 
     In one form the step of initiating movement of the first piston with respect to the first cylinder comprises initiating movement of a second piston with respect to a second cylinder, the second piston and second cylinder being part of a second piston and cylinder assembly which is in fluid communication with the first piston and cylinder assembly. 
     In one form the step of initiating movement of the second piston with respect to the second cylinder comprises engaging the second piston and cylinder assembly with a pipe expander such that actuation of the pipe expander causes movement of the second piston with respect to the second cylinder; and actuating the pipe expander. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment of the present invention will now be described, by way of example only with reference to the accompanying drawings, in which: 
         FIG. 1  is a side view of the first actuator of an extension for a pipe expander according to one embodiment of the invention; 
         FIG. 2  is a side view of the second actuator of an extension for a pipe expander for use with the first actuator shown in  FIG. 1 ; 
         FIG. 3  is a cross sectional view of the actuator of  FIG. 1  in an intermediate retracted position; 
         FIG. 4  is a cross sectional view of the actuator of  FIG. 2  in an intermediate position; 
         FIG. 5  is a cross sectional view of the actuator of  FIG. 1  in the extended position; and 
         FIG. 6  is a cross sectional view of the actuator of  FIG. 2  in the extended position 
         FIG. 7  is a cross sectional view of an extension for a pipe expander according to one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the Figures, disclosed is an assembly  1  for actuating a pipe expander (not illustrated). The assembly  1  includes a first actuator  10  and a second actuator  20  which are operatively engaged. 
     The first actuator  10  comprises a housing  11  which defines an internal chamber  12 . A piston  13  is positioned within internal chamber  12  and is moveable within internal chamber  12  with respect to the housing. The piston  13  is sealed within internal chamber  12  by O rings  14 . Thus internal chamber  12  is closed at one end by the piston  13  and O-rings  14 . 
     The piston  13  includes a shuttle pin  17  which extends from the piston  13  in the direction of forward movement of the piston  13  within the housing  11 . The shuttle pin  17  extends through an opening  19  in housing  11 . 
     The piston  13  is moveable within the housing  11  between a retracted position, as best shown in  FIG. 7 , in which the piston is positioned toward the rear of the chamber  12  and the shuttle pin  17  extends only partially from the opening  19  in the housing  11  and an extended position, as best shown in  FIG. 5 , in which the shuttle pin  17  extends further from the opening  19  in the housing  11 . An intermediate position is shown in  FIG. 3 . Piston  13  includes a shuttle pin  17 . The piston is biased into its retracted position by return spring  18  which is positioned in internal chamber  12 . 
     First actuator  10  is arranged to receive a pipe expander head at threaded portion  15 . First actuator  10  further includes a service end cap  16  which is positioned at the end of chamber  12  distal from shuttle pin  17  and is removable to allow for servicing and assembly. 
     Shuttle pin O-ring  19  provides a seal about shuttle pin  17  to seal chamber  12 . 
     The second actuator  20  comprises a housing  21  which defines an internal chamber  22 . A piston  23  is positioned within internal chamber  22  and is moveable within internal chamber  22  with respect to the housing  21 . The piston  23  is sealed within internal chamber  22  by O rings  24 . Thus internal chamber  22  is closed at one end by the piston  23  and O-rings  24 . 
     Second actuator  20  is arranged to operatively engage with and receive a pipe expander (not illustrated) at threaded portion  25 . The pipe expander attaches with second actuator  20  and acts upon piston  23  to initiate movement of piston  23  within chamber  22 . 
     Piston  23  is moveable between an actuated position, shown in  FIG. 6 , in which the piston  23  is positioned away from clip  27  and a retracted position as shown in  FIG. 7 , in which the piston rests against clip  27 . The piston  23  is biased into the retracted position by return spring  28  and operates against return spring  28 . Clip  27  retains piston  23  inside housing  21  while allowing piston  23  to be contacted from external to the second actuator  20 . 
     The assembly  1  further includes hydraulic hose  30  which is in fluid communication with both chamber  12  and chamber  22 . As a result chambers  12  and  22  are in fluid connection with one another. Hydraulic fluid fills both chambers  12  and  11  and the hose  30 . Hydraulic fluid may be introduced at refill plug  29 . Hydraulic hose  30  can be made any suitable length, though hose lengths of 0.2 m to 0.5 m are particularly suitable. 
     It can be seen that movement of piston  23  within chamber  22  effects a pressure change in the hydraulic fluid within chamber  22 . This, in turn, is transferred to effect a pressure change on the hydraulic fluid in chamber  12  and thus to initiate movement of piston  12 . 
     The assembly  1  comprising first actuator  10  and second actuator  20  connected by hydraulic hose  30  is used in conjunction with a pipe expander (not illustrated). Second actuator  20  is fitted to a pipe expander by screwing actuator  20  onto the pipe expander at threaded portion  25 . Second actuator  20  is designed such that the pipe expander acts on piston  23 . 
     An appropriate expander head (not shown) to suit the particular diameter of pipe (not shown) to be expanded is engaged with threaded portion  15  of first actuator  10 . 
     When the pipe expander is actuated (for example, by squeezing its handles together), the mechanism of the pipe expander bears against and effects movement of piston  23 . This in turn causes pressure to increase in chamber  22  which causes flow of hydraulic fluid through hydraulic hose  30  into chamber  12  to effect a corresponding increase of pressure in chamber  12  and a resultant movement of piston  13  into its extended position. Piston  13  in turn moves shuttle pin  17  which causes actuation of the expander head in the usual manner to deform the end of a pipe to expand the pipe. 
     When the handles of the pipe expander are released, the mechanism of the pipe expander retracts. Return springs  18  and  28  then expand to move pistons  13  and  23  back to their retracted positions as shown in  FIGS. 3 and 4 . 
     Use of the assembly  1  allows first actuator  10  to be brought against the end of a pipe to be expanded when the pipe end is in a position that would otherwise be inaccessible by use of a pipe expander alone, such as a position close to an internal corner, or buried in concrete. The first actuator is then actuated from a distance through hydraulic hose  30 . Use of the extension avoids the need, or reduces the need, to make or enlarge holes in floors or walls to gain access to expand a pipe end. The extension thus saves time and effort to effect plumbing repairs and installations. 
     It is to be appreciated that various alterations or additions may be made to the parts previously described without departing from the spirit or ambit of the present invention. While the assembly has been described with respect to a hydraulic actuation, persons skilled in the art would recognise that actuation by electrical or mechanical means would fall within the scope of the claims. The hydraulic hose could be replaced by an electrical conduit while each piston and cylinder could be replaced by mechanically or electrically actuated shuttle pins moving with respect to a housing. 
     Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated.