F0RM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1 .Title of the invention: FERRULE JOINT ASSEMBLY FOR TUBE FITTING


2. Applicant(s) (a) NAME :
Larsen & Toubro Limited
(b) NATIONALITY :
(c) ADDRESS :
An Indian Company.
Larsen & Toubro Limited L&T House, Ballard Estate, P.O Box No.278, Mumbai 400001 Maharastra, India.
3. PREAMBLE TO THE DESCRIPTION

The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
Accordingly, the present invention relates to a ferrule joint assembly for tube fittings. More particularly, the invention relates to a ferrule joint assembly comprising components integrated in a manner to provide finger-tight fitting of the tube in the assembly. The invention also relates to a ferrule being designed in a manner to be used in the assembly or any other assembly in an effective way.
BACKGROUND AND THE PRIOR ART
Conventional ferrules were made of metal, as a result of which the said ferrule would bite the tube deforming it badly. Further, slight over tightening also results in damage to tube, increasing chances of leakage. Moreover, the deformed tubes cannot be reused. Further, during servicing the joint, it is difficult to remove metallic ferrule as it grips the tube badly. So it is required to cut the end of the tube to form the non-de formed end. However, due to shortening of the length of the tube, reassembly distorts tube. Alternatively, the tube has to be changed, making it uneconomical.
US 3472532 describes to an improvement in coupling for flareless tubes, the coupling being of the type having a compression chamber therein between relatively movable members, a gasket seal in the compression chamber for sealingly engaging the tube, and a ferrule carried by the gasket for gripping the tube to prevent axial displacement. US 7407196 describes to a tube fitting for a tube end, comprising: a female threaded coupling member and a male

threaded coupling member that are threadably joined together to assemble the fitting onto a tube end; said female threaded coupling member having a tube gripping device attached thereto; said tube gripping device separating from said female threaded member during assembly of the fitting to a pulled -up condition.
Thus there is a need to provide a ferrule joint assembly comprising a ferrule that prevents deformation of the tubes.
The present inventors have found that the use of an uniquely designed ferrule in a ferrule joint assembly avoids deformation of the tubes. Further use of plastic ferrule is economical. Further it has been found that a joint assembly comprising the ferrule and other components integrated and inter-engaged in a specific manner provide an improved finger-tight fitting to the tube. This gives the joint a proper rigidity i.e., better distribution of any internal stresses .
OBJECTS OF THE INVENTION
Accordingly, one object of the present invention is to overcome the disadvantages/drawbacks of the prior art.
Another object of the present invention is to provide a ferrule joint assembly for use in tube fittings.
Another object of the present invention is to provide a ferrule.

Another object of the present invention is to provide a ferrule which is not compressible and is deformed and fills all the compression chamber as tightening is completed.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is
provided a ferrule joint assembly for use in tube fittings,
said joint assembly comprising :
an adapter having external threading at both ends;
ferrule means having tapered ends being located inside said
adapter in a manner that tube which being inserted in said
adapter at its one end is received by said ferrule whereby
said ferrule provides secured fitting to said tube;
a ferrule nut having internal threading at its end
comprises a chamfer forming conical surface;
wherein said adapter means comprises a chamfered conical
surface; and
wherein said adapter means, ferrule means and ferrule nut
being located one inside the other such that they are in
lateral superficial engagement so as to apply appropriate
wedging pressure on the ferrule thereby pressing the tube
inside it.
According to another aspect of the present invention there is provided a ferrule for use in tube joints, said ferrule comprising plural tapered ends wherein said ends are provided with step profile such that easy flow of deformed material and avoiding cutting of sharp end is facilitated.
The other objects and advantages of the present invention will be apparent from the description provided hereinbelow

with reference to the accompanying figures and detailed description provided herein below.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 demonstrates a ferrule joint assembly of the present invention.
Figures 2 (a) , (b) and (c) demonstrate the components of the ferrule joint assembly of the present invention.
Figure 3 demonstrates ferrule joint in finger-tight condition.
Figure 4 demonstrates ferrule joint assembly after tightening
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Accordingly, the present invention relates to a ferrule joint assembly (Figure 1) shown as (1) comprising a plastic ferrule (2), a ferrule nut (3) and an adapter (4). At the open end of the tube (5) to be assembled, the said nut (3) and plastic ferrule (2) are inserted. The tube (5) is then inserted in the adapter (4) and the nut (3) is screwed onto the fitting.
The ferrule (2) (also shown in figure 2b) is a cylindrical plastic ferrule, with tapered ends. The ends of the ferrule (2) are not sharp and facilitates easy flow of deformed

material and avoids the cutting of sharp end. Moreover, it facilitates the ejection by ejectors in molding. The ferrule gets deformed and fills the compression chamber as tightening is completed. Further, the plastic ferrule is not compressible.
The ferrule nut (3) (also shown in figure 2a) has internal threading at the end of which there is a" chamfer forming conical surface (6) to apply a wedging pressure on the ferrule {2).
The assembly (1) also comprises an adapter (4) (also shown in figure 2c), which is threaded at both ends. At one end the threading corresponds to the female threading on the component to which it is assembled in the hydraulic circuit. At the other end, the external threading corresponds to the internal threading on the ferrule nut (3) .
As the nut (3) traverses along the axis of the joint after screwing, the space in between the fitting and nut (3) , called as compression chamber reduces and finally the wedging surfaces of ferrule nut (3) and adapter (4) are touching the tapered surface (7) of ferrule (2) {also shown in figure 3). In this condition, the ferrule joint is called finger-tight. As the further tightening is done, the wedging surface of ferrule nut (3) tries to apply a 360°C pressure on the tapered end (7) on the ferrule (2) . At the same time exerts an axial force to press the ferrule towards the adapter side. While the conical surface of adapter also applies a 360°C pressure on the tapered end of ferrule to press it onto the tubes. The tapered ends start plastically deforming. After complete tightening, there is

a sealing contact formed at the wedging surface of adapter and tapered surface of ferrule as well as inner surface of ferrule and outer surface of tube, referred as sealing ring (8) (shown in figure 4). While the wedging surface of ferrule nut (3) presses the tapered end (7) of ferrule (2) to form a firm grip or bite on the tube referred to as biting ring (9) {Figure 4}.
Advantages of the ferrule joint assembly
1. Better sealing joint with firm grip on the tube without much deformation of the tubes.
2. Doesn't deform the tubes in large extent so no damage done to tubes, avoiding any leakage.
3. Aluminum tubes can be used, so the cost incurred in the production and maintenance is less.
4. The operation of joining is simple and doesn't require any preparation for joint. Just the required components need to be assembled.
5. Ease in maintenance as only ferrules need to be carried at the assembly by servicemen as all the other parts can be reused, including the tubes.
6. The tooled up plastic ferrules provide a lot more consistency in terms of dimensions and tolerances so that there is consistency and repeatability of the ferrule.
7. Better damping is provided for any vibrations that may occur during the operation.
The structure thus conceived is adaptable to numerous modifications or variations. In practice the materials and dimensions may be dependant upon specific requirements and that will be comprised within its true spirit.

WE CLAIM
1. A ferrule joint assembly for* use in tube fittings,
said joint assembly comprising :
an adapter having external threading at both ends;
ferrule means having tapered ends being located inside
said adapter in a manner that tube which being
inserted in said adapter at its one end is received by
said ferrule whereby said ferrule provides secured
fitting to said tube;
a ferrule nut having internal threading at its end
comprises a chamfer forming conical surface;
wherein said adapter means comprises a chamfered
conical surface; and
wherein said adapter means, ferrule means and ferrule
nut being located one inside the other such that they
are in lateral superficial engagement so as to apply
appropriate wedging pressure on the ferrule thereby
pressing the tube inside it.
2. Assembly as claimed in claim 1 wherein said adapter comprises step profiles on its internal surface adapted to provide resting surface to the tube.
3. Assembly as claimed in claim 1 wherein said adapter further comprises chamfered surface adapted for applying wedging pressure on the ferrule.
4. Assembly as claimed in claim 1 wherein the ferrule nut comprises a chamfered conical surface adapted to apply wedging pressure on the ferrule.


5. Assembly as claimed in any preceding claims wherein the ferrule nut is adapted to apply about 360° pressure on the tapered end on the ferrule.
6. Assembly as claimed in any preceding claims further comprises sealing ring.
7. Assembly as claimed in any preceding claims further comprises biting ring.
8. A ferrule for use in tube joints, said ferrule comprising plural tapered ends wherein said ends are provided with step profile such that easy flow of deformed material and avoiding cutting of sharp end is facilitated.
9. Ferrule as claimed in claim 8 further adapted to facilitate ejection.
10. Ferrule as claimed in claim 8 is substantially cylindrical.
11. Ferrule as claimed in any preceding claims being made of plastic material.
12. A ferrule joint assembly and a ferrule for use tube fittings as herein substantially described and illustrated with reference to the accompanying figures.
Dated this 15th day of December 2008 /I
Abhishek Sen Of S. Majumdar & Co. Applicant's Agent