Claims:We claim:

1. A fuel injector (10) comprising at least a nozzle body (210), characterized in that said fuel injector (10) comprising:
- a nozzle retaining nut (202) having a groove (204);
- a copper sealing washer (206) having a groove (208), said copper sealing washer (206) located at the operational bottom surface of said nozzle retaining nut (202); and
- a lock ring (30) holding together said nozzle retaining nut (202) and said copper sealing washer (206) in a manner such that at least a part of said lock ring (30) engages said groove (204) on said nozzle retaining nut (202) and at least a part of said lock ring (30) engage said groove (208) on said copper sealing washer (206).
2. A fuel injector (10) as claimed in claim 1, wherein said lock ring (30) comprising:
- a body (214), said body (214) being a circular frame;
- a spheroid shoulder (212) comprising a flat circular collar and a spheroid ring;
- a lock washer seat (216), said lock washer seat (216) on the operative bottom of the body (214); and
- a slit (302).
3. The fuel injector (10) as claimed in claim 2, said fuel injector comprising the lock ring (30), said lock ring (30) comprising the spheroid shoulder (212), said spheroid shoulder (212) engaging the groove (204) on the inner surface at the operative bottom of said nozzle retaining nut (202).
4. The fuel injector (10) as claimed in claim 2, said fuel injector comprising the lock ring (30), said lock ring (30) comprising the lock washer seat (216), said lock washer seat (216) engaging the groove (208) on the inner surface at the operative top of said copper sealing washer (206).
5. The fuel injector (10) as claimed in claim 2, said fuel injector comprising the lock ring (30), said lock ring (30) comprising a plurality of lugs on the body (214).
, Description:Field of the invention:
[0001] The present disclosure relates to a fuel injector, and particularly relates to a lock ring for the copper sealing washer of the fuel injector.
Background of the Invention:
[0002] In the currently existing scenario of a fuel injector, a copper sealing washer is one of the important interface parts between a common rail injector and an engine cylinder head. The function of the copper sealing washer is to seal the injector and the engine cylinder head, thereby preventing combustion gas leakage. Therefore, the copper sealing washer should not be missed during assembly of the injector on to the engine cylinder head as this may result in leakage of combustion gas.
[0003] In the existing design the copper sealing washer has four lugs on inner surface which interfaces with nozzle shaft of the injector. Due to interference fit between the nozzle shaft and the copper sealing washer, the copper sealing washer is arrested in radial movement. But there is no locking mechanism to arrest in axial direction. In most of the injectors, a common occurrence causing trouble is that the copper sealing washer loosens either during transit or during assembly onto engine cylinder head. This leads to missing of copper washer in injector assembly during assembly of the injector inside engine cylinder head.
[0004] Therefore there exists the requirement of a solution to arrest the axial movement of the copper sealing washer on the nozzle shaft and between nozzle retaining nut and the engine cylinder head, as described in this solution.

Brief Description of Drawings:
[0005] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0006] Fig. 1 illustrates a fuel injector with a nozzle body, comprising the lock ring, a copper sealing washer and a nozzle retaining nut.
[0007] Fig. 2 illustrates a nozzle body of a fuel injector, comprising the lock ring, a copper sealing washer and a nozzle retaining nut.
[0008] Fig. 3 illustrates a lock ring for a copper sealing washer of a fuel injector in front, top and sectional view.
Detailed description of the embodiments:
[0009] Fig 1 illustrates a fuel injector (10) comprising a nozzle body (210). A fuel injector (10) normally comprises a nozzle retaining nut (202) and a copper sealing washer (206). In the disclosed invention in Fig 1, an additional element called a lock ring (30) is depicted. The lock ring (30) here prevents the axial movement of the copper sealing washer (206) on the nozzle body (210), by arresting the copper sealing washer (206) axially on the nozzle body (210).
[0010] Fig 2 illustrates the nozzle body (210) of the fuel injector (10), along with the nozzle retaining nut (202), the copper sealing washer (206) and the lock ring (30). Here, the copper sealing washer (206) is located at the operational bottom surface of said nozzle retaining nut (202).
[0011] In the disclosed invention as depicted in Fig 2, the nozzle retaining nut (202) is manufactured having a groove (204). Similarly, the copper sealing washer (206) is also manufactured having a groove (208). The lock ring (30) holds the nozzle retaining nut (202) and the copper sealing washer (206) together. The holding together of the three components are in a manner such that one part of the lock ring (30) engages the groove (204) on the nozzle retaining nut (202) and another part of the lock ring (30) engages the groove (208) on the copper sealing washer (206).
[0012] Fig 3 illustrates the lock ring (30) in its top view, front view, and front sectional view. The lock ring (30) comprises a body (214), a spheroid shoulder (212), a lock washer seat (216) and a slit (302). The body (214) of the lock ring (30) is a circular frame and the spheroid shoulder (212) comprises a flat circular collar and a spheroid ring.
[0013] The spheroid shoulder (212) is at the operative top of the body (214) and the lock washer seat (216) is at the operative bottom of the body (214). In addition to this, as depicted in Fig 3, the slit (302) is a cut on the lock ring (30), passing through the entire ring vertically.
[0014] In one embodiment of the invention, the spheroid shoulder (212) of the lock ring engages the groove (204) on the inner surface at the operative bottom of the nozzle retaining nut (202). Similarly, the lock washer seat (216) engages the groove (208) on the inner surface at the operative top of said copper sealing washer (206).
[0015] The depths of grooves on the nozzle retaining nut (202) and the copper sealing washer (206) are such that the optimum pull-out force necessary to unlock the lock ring (30) from nozzle retaining nut (202) and the copper sealing washer (206) is achieved.
[0016] The lock ring (30) is fixed in place by the locking mechanism wherein the lock ring (30) engages the grooves (204, 208) of the nozzle retaining nut (202) and the copper sealing washer (206). This locking is by compressing the lock ring (30) towards the slit (302) before locking it in place and then decompressing the slit (302) such that the locking (30) holds the copper sealing washer (206) in place. This process of locking takes place during the assembly of the fuel injector (10).
[0017] In one embodiment of the invention the lock ring (30) may be assembled on to nozzle retaining nut (202) after completing injector assembly. In this embodiment, the lock ring (30) snaps in and axially locks itself to the nozzle retaining nut (202). The copper sealing washer (206) is then aligned with the lugs of lock ring (30). Appropriate force is applied on the copper sealing washer (206) to get interfaced with the operating bottom surface of the nozzle retaining nut (202) such that the spheroid shoulder (212) and the lock washer seat (216) are properly assembled in the corresponding grooves.
[0018] In addition to this, the lock ring (30) comprises four lugs on the body (214). The copper sealing washer (206) also has four lugs on its surface. The lugs on the lock ring (30) aids the lock ring (30) get aligned with the copper sealing washer (206) by aligning the lugs on the lock ring (30) along the space in between the lugs on the copper sealing washer (206) . This ensures that that there are is no interference in the lug region and the components stay aligned.
[0019] This design concept along with the locking mechanism arrests the movement of copper sealing washer (206) axially prevents the copper sealing washer (206) from falling off.
[0020] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.