Field of the invention
[0001] This invention relates to a compression spring, and more specifically to a compression spring for a high pressure fuel pump.
Background of the invention
[0002] US 4291809 A describes a pencil holder that includes a body having a socket, the body including a substantially horizontal base portion. A pencil is selectively received in the body socket and engages a compression spring located longitudinally within the body socket. A hook having a hooked end portion within the base portion and a longitudinal portion extending the length of the spring within the body socket and engaging the spring to retain the spring compressed upon insertion of the pencil in the body socket. A catch block within the base portion selectively engages the hooked end portion of the hook when the spring is in a compressed state. A guide vane is located adjacent to the catch block. The guide vane has a curved end underlying the catch block. The guide vane engages the hooked end portion, and the curved end aligns the hooked end portion with the catch block when the spring is being compressed. A piston-operated plunger selectively engages the hooked end portion of the hook for disengaging the hooked end portion from the catch block to release the spring for launching the pencil. A remotely located pneumatic pump is operatively connected to the plunger by a line for pneumatically actuating the plunger when the pump is operated.
Brief description of the accompanying drawing
[0003] Figure 1 illustrates a compression spring for a high pressure fuel pump in one embodiment of the invention.

Detailed description of the embodiments
[0004] Figure 1 illustrates a compression spring 10 for a high pressure fuel pump in one embodiment of the invention. The compression spring 10 for the high pressure fuel pump comprises a first end portion 12 comprising a first hooked portion 14, and a second end portion 16 comprising a second hooked portion 18. A plurality of spring elements 20 are secured between the first hooked portion 14 and the second hooked portion 18, wherein a first end 22 of the plurality of spring elements 20 is inserted through the first hooked portion 14 by winding the first end 22 of the plurality of spring elements 20 around the first hooked portion 14 such that the first hooked portion 14 is inserted within the first end 22 of the plurality of spring elements 20, and wherein a second end 24 of the plurality of spring elements 20 inserted through the second hooked portion 18 by winding the second end 24 of the plurality of spring elements 20 around the second hooked portion 18 such that the second hooked portion 18 is inserted within the second end 24 of the plurality of spring elements 20.
[0005] In an exemplary embodiment, the compression spring 10 for the high pressure fuel pump comprises a first end portion 12 that comprises a first hooked portion 14. The first hooked portion 14 is manufactured independently from a hardened steel material that possesses a greater stiffness than that of the plurality of spring elements 20. Moreover, the diameter of the first hooked portion 14 is greater than the diameter of the plurality of spring elements 20. Therefore, the first hooked portion 14 can withstand greater stress and resist deformation when suspended on a tensile load. More specifically, as a tensile load is applied on the first hooked portion 14, the first hooked portion 14 is subjected to deformation and bending. Owing to the greater diameter and stiffness of the first hooked portion 14, the first hooked portion 14 does not deform considerably in comparison with the first hooked portion 14 of a relatively smaller diameter and lower stiffness.

[0006] In the exemplary embodiment, the compression spring 10 for the high pressure fuel pump comprises a second end portion 16 that comprises a second hooked portion 18. The second hooked portion 18 is manufactured independently of a hardened steel material that has a greater stiffness than that of the plurality of spring elements 20. Moreover, the diameter of the second hooked portion 18 is greater than the diameter of the plurality of spring elements 20. Therefore, the second hooked portion 18 can withstand greater stress and resist deformation when suspended on a tensile load. More specifically, as a tensile load is applied on the second hooked portion 18, the second hooked portion 18 is subjected to deformation and bending. Owing to the greater diameter and stiffness of the second hooked portion 18, the second hooked portion 18 does not deform considerably in comparison with the second hooked portion 18 of a relatively smaller diameter and lower stiffness.
[0007] In the exemplary embodiment, a plurality of spring elements 20 are secured between the first hooked portion 14 and the second hooked portion 18. More specifically, a first end of the plurality of spring elements 20 is inserted through the first hooked portion 14 by winding the first end of the plurality of spring elements 20 around the first hooked portion 14 such that the first hooked portion 14 is inserted within the first end 22 of the plurality of spring elements 20. Therefore, the first end 22 of the plurality of spring elements 20 circumscribes the first hooked portion 14 to retain the first hooked portion 14 within the first end 22 of the plurality of spring elements 20. No mechanical fastening means other than the winding of the plurality of spring elements 20 is used to secure the plurality of spring elements 20 to the first hooked portion 14.
[0008] In the exemplary embodiment, the plurality of spring elements 20 are secured to the second hooked portion 18. More specifically, a second end of the plurality of spring elements 20 is inserted through the second hooked portion 18 by winding the

second end of the plurality of spring elements 20 around the second hooked portion 18 such that the second hooked portion 18 is inserted within the second end of the plurality of spring elements 20. Therefore, the second end of the plurality of spring elements 20 circumscribes the second hooked portion 18 to retain the second hooked portion 18 within the second end of the plurality of spring elements 20. No mechanical fastening means other than the winding of the plurality of spring elements 20 is used to secure the plurality of spring elements 20 to the second hooked portion 18.
[0009] The first hooked portion 14 and the second hooked portion 18 is therein secured to the plurality of spring elements 20 by inserting the plurality of spring elements 20 through the first hooked portion 14 and the second hooked portion 18. Once assembled, the first hooked portion 14, the plurality of spring elements 20, and the second hooked portion 18 constitutes a unitary assembly. Once the first hooked portion 14 and the second hooked portion 18 is each secured to a corresponding attachment device that is opposite to the plurality of spring elements 20, the attachment device exerts a tensile load on the first hooked portion 14 and the second hooked portion 18. The tensile load that is exerted on the first hooked portion 14 and the second hooked portion 18 causes the plurality of spring elements 20 to get elongated, thereby acting as a tension spring. When the tensile load on the first hooked portion 14 and the second hooked portion 18 is released, the plurality of spring elements 20 gets compressed and is restored to its original position. The winding of the spring elements 20 around the first hooked portion 14 and the second hooked portion 18 allows for the first hooked portion 14 and the second hooked portion 18 to be manufactured of a diameter and material that is greater and stiffer respectively than that of the plurality of spring elements 20.
[0010] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the

embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.

We Claim
1. A compression spring (10) for a high pressure fuel pump, said compression
spring (10) comprising:
a first end portion (12) comprising a first hooked portion (14); a second end portion (16) comprising a second hooked portion (18); characterized in that
a plurality of spring elements (20) secured between said first hooked portion (14) and said second hooked portion (18), wherein a first end (22) of said plurality of spring elements (20) inserted through said first hooked portion by winding the first end (22) of said plurality of spring elements (20) around said first hooked portion (14) such that said first hooked portion (14) is inserted within the first end (22) of said plurality of spring elements (20), and wherein a second end (24) of said plurality of spring elements (20) inserted through said second hooked portion (18) by winding the second end (24) of said plurality of spring elements (20) around said second hooked portion (18) such that said second hooked portion (18) is inserted within the second end (24) of said plurality of spring elements (20).
2. The compression spring (10) for a high pressure fuel pump in accordance with
Claim 1 wherein said first hooked portion (14) is gripped and secured within a
plurality of coils of the first end (22) of said plurality of spring elements (20)
such that said first hooked portion (14) cannot be withdrawn from within the
plurality of coils of said plurality of spring elements (20), and wherein said
second hooked portion (18) is gripped and secured within a plurality of coils
of the second end (24) of said plurality of spring elements (20) such that said

second hooked portion (18) cannot be withdrawn from within the plurality of coils of the second end (24) of said plurality of spring elements (20).