Amusement devices – Swing – Motor operated
Reexamination Certificate
1998-01-18
2001-09-04
Nguyen, Kien T. (Department: 3712)
Amusement devices
Swing
Motor operated
C185S043000
Reexamination Certificate
active
06283870
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a spring motor mechanism, and in particular, to a spring, motor mechanism for use in a child's swing having an adjustable swing height control mechanism, an over-wind protection device, and a remaining swing run indicator device.
2. Description of the Related Art
Spring motor mechanisms are well known and subject to various applications, however, they are especially suited for use in a child's swing and will therefore be particularly described in that connection. Child swings are often powered by a torsion spring, typically formed from wire, that receives and stores an input torque when wound by an operator through use of a handle linked to a crank shaft. The handle and crankshaft are typically located at the “escapement end” of the device, controls the release of the torque stored in the spring to sustain a decreasing, periodic oscillation that drives a swing seat containing a child.
Springs used in known spring motor mechanisms typically include a plurality of coils. As the spring is wound, the number of these coils increases while the diameter of each coil decreases. In this way, the length of the spring grows while its diameter shrinks. Springs often have coils within coils in a “telescope” fashion to allow room for additional coils within a limited space.
The energy generated during winding is stored in the spring, and this energy is released as the spring unwinds to oscillate the swing. The stored energy will continue to be released as the added spring coils unwind. Accordingly, for purposes of swing duration, it is the number of additional coils created during winding that is significant rather than the actual amount of torque that has been stored in the spring.
Spring motor mechanisms driven by wound torsion springs suitable for use in a child's swing are previously known and have been disclosed, for example, in U.S. Pat. Nos. 4,165,872 to Saint and 5,083,773 to Saint, among others. In the known device, the torsion spring is wound to create a torque that acts upon a ratchet wheel and a carriage thereby causing the swing, which is attached to the carriage, to oscillate.
In the known mechanism, the winding end of the device includes a handle and crankshaft structure as discussed above. The crank shaft is directly connected to the spring so that the rotation of the handle and crankshaft winds the spring. As discussed above, the rotational force applied to the spring by the rotating handle tightens the spring coils causing the coils to shrink in diameter. Eventually, with over winding, the wire spring will deform plastically, possibly damaging the torsion spring. Thus, a first disadvantage with known spring motor mechanisms is that the spring may become damaged if it is overwound by the operator.
Of course, repeated over winding of the spring can place substantial stress and strain on the main spring. If the main spring should inadvertently become disengaged with either the wind end or the escapement end, or if the main spring breads, the spring could begin to unwind rapidly, and generate an alarming sound.
Conventional spring motor mechanism unwind quickly and suffer from the disadvantage of failing to function for extended periods of time before requiring additional winding. Because the conventional spring motor mechanism is contained within a housing, the user cannot determine how tightly the spring is wound. Conventional spring motor mechanism do not provide the operator with an indication of the number of swing oscillations that can be completed before the spring must be rewound (i.e., the amount of stored energy remaininig in the spring).
Another disadvantage of conventional spring motor mechanisms relates to the nonlinear release of energy form the spring over time as the child swinigs. Specifically as the conventional spring motor mechanism first begins to unwind, the spring mechanism generates a relatively high torque output which swings the child very high. As the spring mechanism unwinds, the torque generated decreases, and the child swing decreases in amplitude. Consequently known spring motor mechanisms can over swing the child as the spring initially unwinds and under swing the child as the springs finishes unwinding.
Known spring motor mechanisms also do not account for variations in the child's weight. Thus, a conventional spring motor mechanism that supplies sufficient torque to appropriately swing a larger heavier child tends to over-swing a smaller lighter child.
SUMMARY OF THE INVENTION
A first object of the present invention is therefore to provide a spring motor mechanism for use in a child's swing that prevents over-winding by the operator. A second object of the present invention is to provide a spring motor mechanism wherein the spring is prevented from unwinding rapidly and uncontrollably. A third object of the present invention is to provide a spring motor mechanism that will generate an increased number of swing oscillations. A fourth object of the present invention is to provide a more accurate indication to the operator of the number of remaining oscillations that can be completed before the spring must by re-wound.
A fifth object of the present invention is to provide a swing that does not oscillate excessively high during initial spring unwinding. A sixth object of the present invention is to provide a spring motor mechanism that can satisfactorily oscillate either a relatively heavy child or a relatively light weight child.
A seventh object of the present invention is to provide a swing housing having rounded edges and that is less of an obstacle when the child user is put in and removed from the child swing. A eighth object of the present invention is to provide a swing housing that is closed at the bottom even when the swing is oscillating, to prevent injury to the operator or child user. A ninth object of the present invention is to provide a swing, that has swing arms that are consistently bent at a proper angle to allow the swing to oscillate longer and in a balanced fashion. A tenth object of the present invention is to provide a handle that does not have an exposed crank wire that could pinch the user's fingers. An eleventh object of the present invention is to provide an internal spring mechanism that is simpler to assemble. A twelfth object of the present invention is to provide an internal spring mechanism that does not generate a noise when it is being wound.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described, the invention provides an over-wind protection system to prevent the over-winding of a motor mechanism for a child swing, comprising a main spring having an energy storing section and an end section, and a spring sleeve having an opening and an inner surface with the end section of the main spring being disposed adjacent to the inner surface, the end section being compressed and exerting an outward force on the inner surface such that the end section and the spring sleeve are fixedly attached when the main spring applies a torque below a predetermined maximum torque is exceeded.
In addition, the invention provides for a wind indicator disposed within a housing, for displaying a relative torque provided by a main spring to the wind indicator comprising a spring coupling connected to an end of the main springs and indicator engaged with the spring coupling for receiving a torque transferred from the main spring, the indicator capable of rotating in response to an applied torque, and a bias spring engaged with the indicator and the housing to provide a counter torque opposite to the main spring torque Such that the indicator's rotational position is altered in response to the torque applied by the main spring and the counter torque applied by the bias spring.
The invention provides for an adjustable swing mechanism for controlling the oscillation angle of a child swing that is powered by torque stored in a main spring comprising a ra
Sack James
Saint David
Foley & Lardner
Graco Children's Products Inc.
Nguyen Kien T.
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