Spring devices – Coil – Including end thrust member
Reexamination Certificate
1999-04-12
2001-03-13
Oberleitner, Robert J. (Department: 3613)
Spring devices
Coil
Including end thrust member
C123S090110, C123S090650
Reexamination Certificate
active
06199843
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a helical spring assembly having a helical spring which engages a member at each end of the spring and, more particularly, to a helical spring assembly which directs the transmission of torque, produced by spring windup, to only one of the members.
BACKGROUND OF THE INVENTION
In any device containing a helical spring which is flexed to store energy, the helical spring will “wind-up” as the spring is compressed, and unwind as the spring is allowed to expand. This winding of the spring imparts torque to the parts constraining the ends of the spring, and to any members attached to the spring constraining parts. An example of a device exhibiting this wind-up condition is an upper spring assembly of an electromagnetic actuator.
A conventional electromagnetic actuator for opening and closing a valve of an internal combustion engine generally includes “open” and “close” electromagnets which, when energized, produce an electromagnetic force on an armature. The armature is biased by a pair of identical upper and lower springs arranged in parallel. The armature is coupled with a gas exchange valve of the engine. The armature rests approximately half-way between the open and close electromagnets when the springs are in equilibrium. When the armature is held by a magnetic force in either the closed or opened position (at rest against the open or close electromagnet), potential energy is stored by the springs. If the magnetic force is shut off with the armature in the opened position, the spring's potential energy will be converted to kinetic energy of the moving mass and cause the armature to move towards the close electromagnet. If friction is sufficiently low, the armature can then be caught in the closed position by applying current to the close electromagnet.
Generally, the upper helical spring of the actuator is in a compressed state and is allowed to expand during operation of the actuator. The upper helical spring is generally constrained at one end by a spring adjusting screw and by a shaft assembly at the other end of the spring. The shaft assembly is coupled to the armature of the actuator. Thus, the upper helical spring can undesirably cause torque to be transmitted to the armature, which should not rotate. One method of preventing rotation of the armature is to provide some guiding mechanism for the armature. However, in a device such as an actuator which operates millions of strokes in its lifetime, a guiding mechanism can wear out quickly.
Accordingly, a need exists to provide a low cost spring assembly which allows one end of the spring to rotate during expansion thereof, yet substantially prevents torque from being transmitted to a member engaged with the other end of the spring.
SUMMARY OF THE INVENTION
An object of the present invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this objective is obtained by providing a spring assembly for an electromagnetic actuator. The actuator has an armature mounted for movement between two electromagnets and a shaft operatively associated with the armature. The spring assembly includes a housing having a surface feature therein and coupled to the actuator. A helical spring is disposed in the housing so as to be compressed and allowed to expand. The spring has first and second ends with the second end biasing the shaft. A spring retainer engages the first end of the spring. The spring retainer has a surface feature therein. A ball bearing is received by the surface feature of the housing and the surface feature of the spring retainer. When the spring is compressed and then expanded, torque produced by the spring is transferred to the ball bearing which rotates with respect to the housing, permitting the first end of the spring to rotate freely while substantially preventing torque from being transferred from the spring to the shaft and armature.
In accordance with another aspect of the invention, a helical spring assembly includes a housing having a surface feature therein. A helical spring is disposed in the housing so as to be compressed and allowed to expand. The spring has first and second ends. The spring retainer engages the first end of the spring. The spring retainer has a surface feature therein. A ball bearing is received by the surface feature of the housing and the surface feature of the spring retainer. A spring biased member is operatively associated with the second end of the spring so as to be biased by the spring. When the spring is compressed and then expanded, torque produced by the spring is transferred to the ball bearing which rotates with respect to the housing, permitting the first end of the spring to rotate freely while substantially preventing torque from being transferred from the spring to the spring biased member.
Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification.
REFERENCES:
patent: 1363398 (1920-12-01), Davics
patent: 1442698 (1923-01-01), Page
patent: 1470102 (1923-10-01), Rahm
patent: 1504774 (1924-08-01), Martin
patent: 1513075 (1924-10-01), Trembley
patent: 1528193 (1925-03-01), Buck
patent: 1596484 (1926-08-01), Garlick
patent: 1905888 (1933-04-01), Berry
patent: 2051313 (1936-08-01), Olenick
patent: 2589418 (1952-03-01), Mitzelfeld
patent: 2660990 (1953-12-01), Zmuda et al.
patent: 2664076 (1953-12-01), Dadd et al.
patent: 2743714 (1956-05-01), Hanson, Jr. et al.
patent: 2827886 (1958-03-01), Geer
patent: 2841128 (1958-07-01), Aiken
patent: 3025841 (1962-03-01), Beckham
patent: 3195528 (1965-07-01), Franklin
patent: 4007716 (1977-02-01), Jones
patent: 4597408 (1986-07-01), Canter
patent: 4827882 (1989-05-01), Paul et al.
patent: 5148779 (1992-09-01), Okuse et al.
patent: 5322039 (1994-06-01), Kinsey
patent: 5832883 (1998-11-01), Bae
patent: 6029789 (2000-02-01), Lindner
patent: 6047673 (2000-04-01), Lohse et al.
patent: 6078235 (2000-06-01), Schebitz et al.
patent: 6082315 (2000-07-01), Schneider
Oberleitner Robert J.
Siemens Automotive Corporation
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