US3964736A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Helical extension spring and method of making same
Assignee: Individual
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Filing: 1974-06-03
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Granted: 1976-06-22
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Expires: 1994-06-03
Abstract
Abstract Helical tension spring having a spring body and two eyelets or loops integrally formed with the body of the spring at the ends thereof, the free ends of the eyelets contacting the end coils of the spring body. Each eyelet is under a prestress force which has to be overcome in order to lift the eyelet from the adjacent end coil of the spring body, such pre-stress force being larger than the force applied at the eyelet, which force is necessary to separate the coils of the spring body by a certain distance. The invention also relates to a process of producing the above spring. At both of the end coils of the spring body there is formed a wire section in a plane approximately normal to the spring body. Such wire section as a whole is bent in the plane containing the axis of the spring body, and the wire section is formed into an eyelet by means of a force acting in the direction of the axis of the spring body, such force being applied approximately in the middle of the wire section as being a tensional force which plastically and elastically deforms the eyelet, so that the end sections of the eyelet elastically contact the end coils of the spring body.
Inventors
- 👤 Joachim Walter Gerhard Huhnen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:09
CPC Classifications
F; F16; F16F; F16F1/00; F16F1/02; F16F1/04; F16F1/12; F16F1/123; B; B21; B21F; B21F35/00; B21F35/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
122 words
A helical tension spring having a spring body and two preformed terminal eyelets formed integrally therewith, the free ends of the eyelets contacting the respective end coils of the spring body, each such eyelet exhibiting a localized outward bend in a substantially axial plane of the spring for exerting an initial axial pre-stress force which has to be overcome in order to lift the eyelets off from the adjacent end coils of the spring body, such initial axial pre-stress force being larger than a force normally applied at the eyelet during the use of the spring, which force causes in the spring body a torsion stress which is on the order of a tenth of the tensile strength of the spring wire.
Claim 2
Dependent Claim
122 words
A helical tension spring having a spring body and two preformed terminal eyelets formed integrally therewith, the free ends of the eyelets contacting the respective end coils of the spring body, each such eyelet exhibiting a localized outward bend in a substantially axial plane of the spring for exerting an initial axial pre-stress force which has to be overcome in order to lift the eyelets off from the adjacent end coils of the spring body, such initial axial pre-stress force being larger than a force normally applied at the eyelet during the use of the spring, which force causes in the spring body a torsion stress which is on the order of a tenth of the tensile strength of the spring wire.
Claim 3
Dependent Claim
165 words
A process for producing a helical tension spring having a spring body and two terminal eyelets formed integrally therewith, which comprises the steps of forming the ends of a coil spring body as wire sections that extend from the spring body in a transverse plane, bending each such end wire section as a whole into an axial plane of the spring body, and plastically and elastically deforming each such bent end wire section into an eyelet exhibiting a localized outward bend in the axial plane of the spring by exerting at least an outward force on such bent end wire section along the spring axis, each resulting eyelet bearing elastically against the adjacent end coil of the spring body with an axial pre-stress force larger than a force normally applied at the eyelet during the use of the spring, which force causes in the spring body a torsion stress which is on the order of a tenth of the tensile strength of the spring wire.
Claim 4
Dependent Claim
165 words
A process for producing a helical tension spring having a spring body and two terminal eyelets formed integrally therewith, which comprises the steps of forming the ends of a coil spring body as wire sections that extend from the spring body in a transverse plane, bending each such end wire section as a whole into an axial plane of the spring body, and plastically and elastically deforming each such bent end wire section into an eyelet exhibiting a localized outward bend in the axial plane of the spring by exerting at least an outward force on such bent end wire section along the spring axis, each resulting eyelet bearing elastically against the adjacent end coil of the spring body with an axial pre-stress force larger than a force normally applied at the eyelet during the use of the spring, which force causes in the spring body a torsion stress which is on the order of a tenth of the tensile strength of the spring wire.
Claim 5
Dependent Claim
24 words
A process according to claim 2, comprising heat treating the deformed and bent wire end sections prior to their last plastic and elastic deformation.
Claim 6
Dependent Claim
93 words
A process according to claim 2 for manufacturing springs having middle or larger ratios of diameters of the end coils to diameter of the spring wire, comprising forming a straight, tangentially extending shank portion as a wire end section, and bending each shank at the starting point in a position in which it extends transversely over the adjacent end coil along a diameter, and holding each of the bent shanks at its free end section and the starting point against the adjacent end coil as long as the pulling force acts on it.
Claim 7
Dependent Claim
95 words
A process according to claim 2 for producing springs with middle or smaller ratios of the diameter of the end coils to the diameter of the spring wire, comprising forming a bent wire end section deviating from the adjacent end coil, bending away the thus formed wire end section at a suitable position of the end coil, and after the plastic and elastic deformation of the wire end section pulling the wire end section onto the end coil, whereby the wire ends after the bending are situated between the planes determined by the end coils.
Claim 8
Dependent Claim
40 words
A process according to claim 5, wherein the wire end sections are more weakly bent than the end coils, and that the putting on of the wire ends is carried out by intensifying the bending of the wire end sections.
Claim 9
Dependent Claim
37 words
A process according to claim 5, wherein the wire end sections are more strongly bent than the end coils, and thus the putting on of the wire ends results from widening of the bent wire end sections.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-22 | 1979-12-22 | 1980-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-22 | 1983-12-22 | 1984-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-22 | 1987-12-22 | 1988-06-22 | $7700.00 | Window Closed / Lapsed |