DESC:FIELD OF INVENTION
The present invention relates to a metal transition fitting used in plumbing and piping system. More particularly, the present invention relates to a metal transition pipe fitting comprising a metal insert with one fourth of inner part having metal threads and three fourth of inner part having plain metal surface, said three fourth of inner part is molded with rigid material to form rigid threads. Further, outer part of the metal insert is completely molded with rigid material. Moreover, the present invention relates to metal transition pipe fitting that prevents rusting of fitting and pipes during long run and prevents breaking or cracking inside or outside the wall of the pipes and the fitting.

DESCRIPTION OF PRIOR ART
Generally a fitting is used in pipe plumbing systems to connect straight pipe or tubing sections, to adapt to different sizes or shapes, and for other purposes, such as regulating or measuring fluid flow. A transition fitting is generally used for switch over to metal to plastic or plastic to metal used for connecting pipe fittings such as for metal taps and showers.

Chlorinated polyvinyl chloride (CPVC) and polyvinyl chloride (PVC) fittings are widely used with CPVC and PVC pipes for supplying water from bottom to top or from top to bottom and distributing the water to rooms such as kitchen, bathroom etc in place of iron pipes and iron fittings. The main disadvantage of this type of pipes and fittings are that they get rusted in long run and pipes and fittings crack or break inside the wall or outside the wall.
Referring to Figure 1, conventional adaptor for connecting either metal threaded fittings or full rigid threaded fittings and also threaded pipes along with either two pipes pasting provision or single pipe pasting provision, said provision or space is called socket, said adaptor includes a full threaded female insert which is made of metal covered with rigid material along with space for pasting unthreaded pipe. In this metal insert, there is full metal thread to fit together so that a threaded fitting or threaded pipe segment is inserted on one end of the female metal thread of the receptor body.

Some of the prior arts are:
US20030184085 discloses an adapter for connecting two segments of pipe, said adapter includes a guide insert made of a rigid material and a receptor body made of a plastic material. Both the guide insert and the receptor body have threads that fit together so that a threaded pipe segment is first inserted into the rigid threads of the guide insert and then transitions to the plastic threads of the receptor body.

US6866305 discloses a pipe fitting which has a body with an internally threaded bore and at least one female starter thread. The at least one female starter thread is disposed either within the bore or immediately outside of the bore. The starter thread is axially aligned with the bore threads. The internally threaded bore is made up of plastic and the female starter thread is made up of metal.

U5437481 discloses a fitting suitable for coupling a plastic pipe to an externally threaded metal element, such as a sprinkler head, comprises a coupling, an external, metallic reinforcing collar on the coupling, an internally threaded insert in the coupling, and an O-ring. The collar is shaped to prevent rotation, and is held in place by a lip on the insert. The O-ring is held in a chamfered recess on the external surface of the insert. The coupling is conventionally injection-molded from a plastic material, such as polyvinyl chloride (PVC), or chlorinated polyvinyl chloride (CPVC).

CN202302525 discloses a novel polyethylene steel-plastic transition pipe fitting, which comprises a polyethylene part and a metal part main body. The transition pipe fitting is characterized by further comprising a wedged metal sleeve and O-shaped sealing rings. Undercut structures are arranged outside one end of the metal part main body, and the end is inserted into one end of the polyethylene plastic part. A part of the metal part main body is connected with the polyethylene plastic part, and the wedged metal sleeve is sleeved on the periphery of the part.

Some of the drawbacks in the prior art are:
• There is a possibility of gap formation between metal insert and rigid material due to poor molding process, which causes leakage.
• Teflon tape is required to avoid leakages.
• Lacks contraction and expansion at different or varying temperatures.

Accordingly, there exists a need for a metal transition pipe fitting that prevents rusting of fitting and pipes during long run and prevents breaking or cracking inside or outside the wall of the pipes and fittings.

OBJECTS OF INVENTION
One or more problems present of the prior art may be overcome by various embodiment of the present invention.

It is the primary object of the present invention to provide a metal transition fitting used in plumbing and piping system.

It is another object of the present invention to provide a metal to plastic transition pipe fitting comprising a metal insert with one fourth of inner part having metal threads and three fourth of inner part having plain metal surface.

It is another object of the present invention, wherein the three fourth of inner part of the metal insert is molded with rigid material to form rigid threads.

It is another object of the present invention, wherein metal male threads butted with the rigid threads eliminates the need for wrapping of Teflon tape to avoid leakage.

It is another object of the present invention, wherein the metal to plastic transition pipe fitting prevents decay of metal insert from the environment.

It is another object of the present invention, wherein the metal to plastic transition pipe fitting prevents breaking or cracking inside or outside the wall of the pipes and the fitting at the time of over tightening.
It is another object of the present invention, wherein the metal to plastic transition pipe fitting does not affects the mechanical properties of the pipe fitting such as bursting.

It is another object of the present invention to provide metal to plastic transition pipe fitting of varying sizes and of various types that includes brass elbow, brass tee and brass female adaptor.

SUMMARY OF INVENTION
Thus according to the basic aspect of the present invention there is provided a metal to plastic transition pipe fitting comprising a metal insert with one fourth of inner part having metal threads with metal ring on its edge and three fourth of inner part having plain metal surface,
wherein said three fourth of inner part of the metal insert is molded with rigid material to form rigid threads, and
wherein outer part of the metal insert is coarse and is provided with one or more plain grooves to accommodate one or more O-rings.

It is another aspect of the present invention, wherein the rigid threads are formed by injection molding technique.

It is another aspect of the present invention, wherein the metal insert has two O-rings on the grooves located on the edges of the metal insert.

It is another aspect of the present invention, wherein the coarse outer part of the metal insert is completely molded with rigid material by injection molding technique.
It is another aspect of the present invention, wherein the metal threads butted with the rigid threads eliminates leakage.

It is another aspect of the present invention, wherein the metal to plastic transition pipe fitting prevents breaking or cracking inside or outside the wall of the pipes and the fitting at the time of over tightening.

It is another aspect of the present invention, wherein the metal is brass.

It is another aspect of the present invention, wherein the rigid material includes chlorinated polyvinyl chloride (CPVC), polyvinyl chloride (PVC) and high density polyethylene (HDPE).

BRIEF DESCRIPTION OF DRAWINGS:
Figure 1: illustrates the perspective view of the metal transition fitting according to the prior art.
Figure 2: illustrates the perspective view of the metal transition fitting according to the present invention.
Figure 3: illustrates the cross sectional view of the metal transition fitting according to the present invention.
Figure 4: illustrates the cross sectional view of the metal transition fitting with metal insert according to the prior art.
Figure 5: illustrates the perspective view of the metal insert according to the prior art.
Figure 6: illustrates the top perspective view of the metal insert with two O-rings according to the prior art.
Figure 7: illustrate the cross section view of the metal insert without ‘O’ ring and with ‘O’ ring according to the prior art.
Figure 8: illustrates the perspective view of the metal insert with two O-rings according to the present invention.
Figure 9: illustrates the cross sectional view of the metal insert according to the present invention.
Figure 10: illustrates the cross sectional view of the metal insert with two O-rings according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
Thus, as described, the present invention is directed towards a metal transition fitting that prevents rusting of fitting and pipes during long run and prevents breaking or cracking inside or outside the wall of the pipes and fittings.

Referring to Figures 2, 3, 8, 9 and 10 of the present invention, the metal to plastic transition pipe fitting comprises of a metal insert having inner part and outer part, wherein one fourth of inner part having metal threads [2] with metal ring [1] on its edge and three fourth of inner part having plain metal surface [3]. The three fourth of inner part of the metal insert is molded with rigid material to form rigid threads [6], said rigid threads [6] are made by injection molding technique as shown in Figures 2 and 3. The outer part of the metal insert is coarse and is provided with one or more plain grooves [4] successively to accommodate one or more O-rings [5]. Preferably, the metal insert has two O-rings [5] on the grooves [4] located on the edges of the metal insert as shown in Figures 8, 9 and 10. The coarse outer part of the metal insert is completely molded with rigid material by injection molding technique.

The metal male threads [2] butted with the rigid threads [6] eliminates the need for wrapping of Teflon tape to avoid leakage. The metal to plastic transition pipe fitting prevents - decay of metal insert from the environment; and breaking or cracking inside or outside the wall of the pipes and the fitting at the time of over tightening. Further, the metal to plastic transition pipe fitting does not affects the mechanical properties of the pipe fitting such as bursting.

The metal is preferably brass. The rigid material includes chlorinated polyvinyl chloride (CPVC), polyvinyl chloride (PVC) and high density polyethylene (HDPE). It is to be noted that metal to plastic transition pipe fitting is provided with varying sizes and types that includes brass elbow, brass tee and brass female adaptor.

Molding technique:
Molds of various sizes and types are prepared and positioned in the injection molding machine. The molds are opened and the metal inserts are inserted in the cavities of the molds. The molds are then closed and the molten rigid material is injected by the help of injection molding machine. The rigid material goes inside the cavity through a passage called runner and spreads surrounding the metal and inside the metal inserts and takes the shape as per the given shape of cavity and punch. The molded metal inserts are allowed to cool to form proper shape and the molded metal inserts are separated by the help of ejector from the mold.

Advantages of the present invention are as follows:
• Provides high tapered sealing joint with polymer material.
• Manages two different materials as metal and plastic.
• Contracts and expands at different or varying temperatures.
• Results zero % leakage.
,CLAIMS:WE CLAIM:
1. A metal to plastic transition pipe fitting comprising a metal insert with one fourth of inner part having metal threads [2] with metal ring [1] on its edge and three fourth of inner part having plain metal surface [3],
wherein said three fourth of inner part of the metal insert is molded with rigid material to form rigid threads [6], and
wherein outer part of the metal insert is coarse and is provided with one or more plain grooves [4] to accommodate one or more O-rings [5].

2. The metal to plastic transition pipe fitting as claimed in claim 1, wherein the rigid threads [6] are formed by injection molding technique.

3. The metal to plastic transition pipe fitting as claimed in claim 1, wherein the metal insert has two O-rings [5] on the grooves [4] located on the edges of the metal insert.

4. The metal to plastic transition pipe fitting as claimed in claim 1, wherein the coarse outer part of the metal insert is completely molded with rigid material by injection molding technique.

5. The metal to plastic transition pipe fitting as claimed in claim 1, wherein the metal threads [2] butted with the rigid threads [6] eliminates leakage.

6. The metal to plastic transition pipe fitting as claimed in claim 1, wherein the metal to plastic transition pipe fitting prevents breaking or cracking inside or outside the wall of the pipes and the fitting at the time of over tightening.

7. The metal to plastic transition pipe fitting as claimed in claim 1, wherein the metal is brass.

8. The metal to plastic transition pipe fitting as claimed in claim 1, wherein the rigid material includes chlorinated polyvinyl chloride (CPVC), polyvinyl chloride (PVC) and high density polyethylene (HDPE).