FIELD OF THE INVENTION

The present invention relates to expander tool for ex- panding an end of a pipe.

BACKGROUND OF THE INVENTION

In prior art, e.g. from US 3888102, is known an ex pander tool for expanding an end of a pipe. The ex- pander tool comprises a tool head which comprises ex panding means arranged to be insertable inside the end of the pipe for expanding the end of the pipe. The ex panding means comprise a plurality of spreading ele ments. The spreading elements are radially movable in relation to a center longitudinal axis of the tool head between a starting position, at which the spread ing elements are close along said axis and insertable into the end of the pipe, to an outwardly extended ex pansion position radially distanced from said axis so as to expand the end of the pipe. Each of the spread ing elements has an outer spreading surface which is an nth part of a cylinder surface, wherein n is the number of the spreading elements. The outer spreading surfaces are configured to press against an interior surface of the end of the pipe. The expander tool com prises a piston configured to spread the spreading el ements from the starting position to the expansion po sition by moving along said axis from a retracted pis ton position to a fully extended piston position against interior surfaces of the spreading elements. The expander tool further comprises an actuator for moving the piston.

The spreading elements may form deformations on the inner surface of the expanded pipe. These deformations may reduce sealing between the pipe and a fitting to be inserted inside the expanded pipe end. OBJECTIVE OF THE INVENTION

The objective of the invention is to provide an im- provement to the expander tool.

In particular, it is an objective of the present in vention to provide an expander tool which can form an undamaged and intact sealing area to the inner surface of the expanded pipe to provide improved sealing be tween the pipe and a pipe fitting to be inserted in side the pipe end.

SUMMARY OF THE INVENTION

According to an aspect, the present invention provides an expander tool for expanding an end of a pipe made of plastics having shape memory. The expander tool comprises a tool head. The tool head comprises expand ing means arranged to be insertable inside the end of the pipe for expanding the end of the pipe. The ex panding means comprise a plurality of spreading ele ments. The spreading elements are radially movable in relation to a center longitudinal axis of the tool head between a starting position, at which the spread- ing elements are close along said axis and are insert- able into the end of the pipe, to an outwardly extend ed expansion position radially distanced from said ax is so as to expand the end of the pipe. Each of the spreading elements has an outer spreading surface which is an nth part of a cylinder surface, wherein n is the number of the spreading elements. The outer spreading surfaces are configured to press against an interior surface of the end of the pipe for expanding the end of the pipe. The expander tool comprises a piston configured to spread the spreading elements from the starting position to the expansion position by moving along said axis from a retracted piston po- sition to a fully extended piston position against in terior surfaces of the spreading elements, and an ac tuator for moving the piston. According to the inven tion the outer spreading surfaces comprise a circum ferential groove, said groove leaving an undamaged smooth and intact sealing surface to the inner surface of the expanded pipe.

The technical effect of the invention is that a seal ing barb of a pipe fitting which will be inserted into the expanded pipe end can seal tightly against the un damaged sealing surface.

In an embodiment of the expander tool, the outer spreading surfaces comprise at least two circumferen tial grooves at a distance from each other.

In an embodiment of the expander tool, the spreading elements comprise a stop face against which the end of the pipe to be expanded can be placed.

In an embodiment of the expander tool, the outer spreading surfaces comprise a circumferential groove disposed near to the stop face, said groove leaving an undamaged smooth and intact sealing surface to the in ner surface of the expanded pipe at the end of the pipe .

In an embodiment of the expander tool, the expander tool comprises a tool frame. The tool head comprises a head frame which is detachably attachable to the tool frame .

In an embodiment of the expander tool, the tool frame comprises an outer thread. The head frame comprises an inner thread adapted to be threaded into the outer thread for detachable attachment of the head frame to the tool frame.

In an embodiment of the expander tool, the spreading element comprises a guide flange. The head frame is a ring comprising a radial inner guide slot adapted to receive the guide flange radially movable in guidance of the guide slot relative to head frame.

In an embodiment of the expander tool, the guide flange comprises a peripheral groove to receive an elastic O-ring therein. The O-ring acts as a returning spring for returning the spreading elements to the starting position.

In an embodiment of the expander tool, the piston com prises a plunger portion having a conical outer sur face, and the spreading elements comprise inner sur faces matching with the shape of the conical outer surface .

In an embodiment of the expander tool, the spreading elements have a conical end portion.

It is to be understood that the aspects and embodi ments of the invention described above may be used in any combination with each other. Several of the as pects and embodiments may be combined together to form a further embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to pro vide a further understanding of the invention and constitute a part of this specification, illustrate embodiments of the invention and together with the de scription help to explain the principles of the inven tion. In the drawings: Figure 1 is an axonometric view of a tool head of the expander tool according to a first embodiment of the invention, the spreading elements being at a starting position,

Figure 2 shows the tool head of Figure 1 in a position where the spreading elements are moved to an expansion position,

Figure 3 is a side view of an expander tool according to one embodiment of the invention, the expander tool being shown as a partial longitudinal section, the tool head being detached,

Figure 4 is a side of the expander tool of Figure 2 the tool head being attached and the spreading ele ments being at a starting position inserted to the an end of a pipe,

Figure 5 shows the expander tool of Figure 4 the spreading elements being moved to an expansion posi tion, Figure 6 shows an expander tool according to a second embodiment of the invention,

Figure 7 shows an enlarged longitudinal section of a pipe and a reinforcing ring both been expanded simul- taneously with the expander tool of Figure 6, shown in an expanded position, and a pipe fitting inserted into the pipe, and

Figure 8 shows the pipe and the reinforcing ring of Figure 7 in a collapsed position. DETAILED DESCRIPTION OF THE INVENTION

Figures 1 to 5 show an expander tool 1 for expanding an end of a pipe. Especially the expander tool 1 is adapted to expand a pipe made of plastics having shape memory. The expander tool 1 is designed and especially suitable to expand the end of the pipes used in plumb ing applications. Such pipes include pipes having shape memory capacity, such as pipes made of PE (poly ethylene) , PEX (cross-linked polyethylene) , PE-RT (Polyethylene of Raised Temperature resistance) , UHMWPE (Ultra-high-molecular-weight polyethylene) which, after being expanded, have a shrinking speed which depends on the temperature of the pipe. The ex pander tool 1 can also be used to expand SACP (Seam less aluminium composite pipe) although it does not have the shape memory capacity. SACP pipe is built up from two concentric plastic layers with an intermedi ate seamless layer of aluminum and all these three layers are attached to each other by adhesive layers. The tool device is also suitable for expanding the ends of metal pipes, such as copper pipes. The expand er tool 1 is preferably a handheld power tool having a handle H by which the operator can hold the expander tool by hand to perform the expansion operation.

Further referring to Figures 1 to 5, the expander tool comprises a tool head 2 which comprises expanding means 3 arranged to be insertable inside the end of the pipe for expanding the end of the pipe. In the shown example, the expanding means 3 is formed of six spreading elements 4. The spreading elements 4 are ra dially movable in relation to a center longitudinal axis x of the tool head 2 between a starting position I (Figures 1 and 4) at which the spreading elements 4 are close along axis x and are insertable into the end of the pipe P, to an outwardly extended expansion po sition II (Figures 2 and 5) radially distanced from said axis x so as to expand the end of the pipe. Each of the spreading elements 4 have an outer spreading surface 5 configured to press against an interior sur face of the end of the pipe. The expander tool 1 fur ther comprises a piston 6 configured to spread the spreading elements 4 from the starting position I to the expansion position II by moving along the axis x from a retracted piston position III shown in Figure 4 to a fully extended piston position IV of Figure 5 against interior surfaces of the spreading elements 13. The expander tool further comprises an actuator 7 for moving the piston 6. The actuator 7 can be for ex ample a hydraulic cylinder whereby the handle may con tain equipment such as a rechargeable battery, a hy draulic pump to produce hydraulic pressure for the hy draulic cylinder, an electric motor for driving the hydraulic pump and an on-off switch, which can be op erated by the operator to control the operation of the tool .

The expander tool 1 comprises a tool frame 10 and the tool head 2 comprises a head frame 11 which is detach ably attachable to the expander tool frame 10. The tool frame 10 comprises an outer thread 12. The head frame 11 comprises an inner thread 13 adapted to be threaded into the outer thread 12 for detachable at tachment of the head frame to the tool frame. The ex pander tool 1 preferably comprises a set of inter changeable and detachably attachable tool heads 2 for different pipe diameters.

The outer spreading surfaces 5 of the spreading ele ments 4 comprise a circumferential groove 8. In the shown embodiment there are two grooves 8 at a distance from each other. The groove 8 leaves an undamaged smooth and intact circumferential sealing surface 100 to the inner surface of the expanded pipe P. Referring also to Figures 7 and 8, when the pipe is made of plastics having shape memory, after expansion, when the pipe P retracts and shrinks down, i.e. collapses,, the sealing surface 100 is the first area to make con tact on the pipe fitting F inserted to the end of the pipe applying full compressive load between the seal ing barb 101 on the fitting F and the sealing surface 100 of the pipe. The result is tight sealing between the pipe P and the pipe fitting F.

The spreading elements 4 comprise a stop face 9 against which the end of the pipe P to be expanded can be placed, as shown in Figure 4.

The spreading element 4 comprises a guide flange 14. The head frame 11 is a ring comprising a radial inner guide slot 15 adapted to receive the guide flange 14 radially movable in guidance of the guide slot 15 rel ative to head frame. The guide flange 14 comprises a peripheral groove 16 to receive an elastic O-ring 17 therein. The O-ring 17 acts as a returning spring for returning the spreading elements 4 to the starting po sition I.

Referring to Figure 3, the piston 6 comprises a plung er portion 18 having a conical outer surface 19. The spreading elements 4 comprise inner surfaces 20 match ing with the shape of the conical outer surface (19) .

The spreading elements 4 have a conical end portion 21. The conical end portion 21 is angled and designed to minimize stress and deformation on the pipe during the expansion process.

Figure 6 shows an expander tool as described above re ferring to Figures 1 to 5 with the exception that in the expander tool of Figure 6 the outer spreading sur- faces 5 comprises a circumferential groove 8' disposed near to the stop face 9. The groove 8' leaves an undam aged smooth and intact sealing surface 100' to the in ner surface of the expanded pipe P at the end of the pipe. Figure 6 also shows that a reinforcing ring 102 made of plastics having shape memory can be expanded together with the pipe P.

Figure 7 shows the pipe P and the reinforcing ring 102 in an expanded position after being expanded with the expander tool of Figure 6. In the expanded position of the pipe P, a pipe fitting F can be inserted into the pipe P. The pipe fitting F comprises three sealing barbs 101, 101' corresponding to the three undamaged smooth and intact sealing surfaces 100, 100' of the inner surface of the expanded pipe P. As can be seen in Figures 7 and 8, the sealing barb 101' is adapted to be engaged at a position behind the inner edge of sealing surface 100' located nearest to the end of the pipe. This sealing barb 101' acts as a retainer. The other two sealing barbs 101 of the pipe fitting F are aligned with the other two undamaged smooth and intact sealing surfaces 100 of the pipe and are pressed against them to form a proper and tight sealing.

Although the invention has been the described in con junction with a certain type of expander tool, it should be understood that the invention is not limited to any certain type of expander tool. While the pre sent inventions have been described in connection with a number of exemplary embodiments, and implementa tions, the present inventions are not so limited, but rather cover various modifications, and equivalent ar rangements, which fall within the purview of prospec tive claims.