Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-04-01
2001-02-06
Yao, Sam Chuan (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S218000, C156S227000, C156S304200, C156S304300, C156S304600, C156S290000, C156S294000
Reexamination Certificate
active
06183584
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for splicing together a pair of drip irrigation hoses using splicing coupling as well as to the splicing coupling.
BACKGROUND OF THE INVENTION
Drip irrigation technology is employed throughout the world for use in the agricultural industry. Hoses for performing drip irrigation are typically installed in fields, orchards, vineyards, nurseries, greenhouses, or anywhere in which drip precipitation is desired, both above and below the ground. An example of a plastic drip irrigation hose is T-TAPE TSX, manufactured by T-Systems International, Inc., San Diego, Calif.
Drip irrigation hose can generally be classified into two types: hose having discrete emitters and hose having continuous, integral emitters. An example of a drip irrigation hose having discrete emitters is shown in U.S. Pat. No. 4,850,531. An example of a drip irrigation hose having continuous, integral emitters is shown in U.S. Pat. No. 4,247,051.
In the use of all types of drip irrigation hoses, it is commonly necessary to splice together a pair of hoses. Several techniques are employed to splice irrigation hoses together. One technique comprises splicing hoses together by using wire ties to secure a piece of rigid tubing inserted inside both hoses. A wire tie is wrapped several times around each hose over the section of the hose that overlaps the rigid tubing and the wire tie is twisted to form a water-tight seal. Problems with this technique are that the rigid tubing causes a substantial deformity in the hoses at the splice and the wire ties may work their way loose over time, thereby destroying the integrity of the water-tight seal.
Another technique is splicing together drip irrigation hoses using a screw-on connector. An internally threaded connector is fit over the outside of each of the irrigation hoses. An externally threaded cylindrical insert is then inserted into both ends of the hoses. The threads on each end of the insert are diametrically oriented. The outer connectors are threaded onto the insert with the irrigation hoses frictionally and engageably squeezed between each of the outer connectors and the insert to form a water-tight seal. A problem with this technique is that a substantial deformity is formed in the hoses at the splice. Moreover, the connectors are bulkier and are harder to handle in the field.
Therefore, there is a need for a technique for splicing together drip irrigation hoses which maintains a permanent water-tight seal and does not result in a substantial deformity at the splice.
SUMMARY OF THE INVENTION
A method is provided incorporating a splicing coupling for splicing together a pair of drip irrigation hoses. The splicing coupling has an inner and an outer member. Each member is formed from a sheet of material having a heat activatable bondable surface opposite a non-bondable surface. Preferably, the bondable surface is a Polyethylene layer while the non-bondable surface is a Mylar layer. The two layers are held together to form the sheet by a tie layer sandwiched between the two layers. The resulting sheet material typically has a thickness in the range of 0.006 inch and is sometimes referred to as a polymylar sheet.
Each member of the coupling is formed by folding a rectangular section of the sheet longitudinally to form overlapping margins. The inner member is formed with the bondable surface on the outside and the non-bondable surface on the inside. The outer member, is formed with the bondable surface on the inside and the non-bondable surface on the outside. To facilitate handling, it is preferable that the inner member is bonded to the outer member. Preferably, this is accomplished by unfolding the outer member and placing the inner member on the section of the outer member between the two folds that form the outer member. Both members should be longitudinally aligned. It is also preferable that the overlapped ends of the inner member face the inner surface of the outer member located between the two folds. In a preferred embodiment, the inner member is bonded to the outer member by placing a heating wire against the outer surface of the outer member such that it is perpendicular to the longitudinal axis of the outer member and such that it makes contact with a portion of the outer member between the two folds. The heating wire is then heated activating the inner bondable surface of the outer member as well as the outer bondable surface of the inner member causing the members to bond along a line corresponding to the position of the heating element. This line is commonly referred to as a bond line.
In preparing to form a splice on the field, the ends of the hoses to be spliced should be cleaned to remove soil and other dirt that may have accumulated on their inner and outer surfaces. Wiping with a clean cloth may be sufficient. To form the splice, the end of the first hose to be spliced is slid over the inner member and under the outer member until it abuts against the bond line. The end of the second hose to be spliced is slid over the other end of the inner member and under the outer member until it also makes contact with the bond line. To facilitate this process, the outer member should preferably be unfolded as the hose ends are slid over the inner member. The outer member is then folded over the outer surfaces of the hose ends. Heat and pressure are then applied preferably by a thermal impulse heater which collapses the coupling and hoses while applying heat, causing the bondable surfaces of the inner and outer members to activate and bond to the inner and outer surfaces of the hoses, respectively. Because the inner surface of the inner member is nonbondable, the inner surfaces do not bond against each other and thereby do not create an obstacle to the flow through the splice. Similarly, the non-bondable outer surface of the outer member will not bond to the heat and pressure applying device.
REFERENCES:
patent: 3612580 (1971-10-01), Jones
patent: 4092193 (1978-05-01), Brooks
patent: 4099749 (1978-07-01), van Vliet
patent: 4465309 (1984-08-01), Nimke et al.
patent: 4610742 (1986-09-01), Rop et al.
patent: 5252162 (1993-10-01), Delmer
patent: 5690769 (1997-11-01), Daigle et al.
Christie Parker & Hale LLP
T-Systems International, Inc.
Yao Sam Chuan
LandOfFree
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