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Single Spring Bidirectional Crash Stop for Use at Central Axis of Linear Voice Coil Motor

IP.com Disclosure Number: IPCOM000081522D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 50K

Publishing Venue

IBM

Related People

Empson, EH: AUTHOR [+4]

Abstract

A bidirectional crash stop for a linear voice coil motor is provided, by means of a single spring assembly placed along the central axis of the voice coil motor. The spring is concentric with a support tube which serves to provide two reference shoulders to preload the spring, and the spring in turn maintains pressure against two movable stop rings. One or both rings may be supported on a tube assembly surrounding the outside diameter of the crash stop spring, so that the two rings may be placed in close juxtaposition to one another. Each ring has an elastomer contact surface on its face serving to contact the moving bobbin assembly, and transfer the energy from the bobbin through the elastomer to the crash stop spring.

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Single Spring Bidirectional Crash Stop for Use at Central Axis of Linear Voice Coil Motor

A bidirectional crash stop for a linear voice coil motor is provided, by means of a single spring assembly placed along the central axis of the voice coil motor. The spring is concentric with a support tube which serves to provide two reference shoulders to preload the spring, and the spring in turn maintains pressure against two movable stop rings. One or both rings may be supported on a tube assembly surrounding the outside diameter of the crash stop spring, so that the two rings may be placed in close juxtaposition to one another. Each ring has an elastomer contact surface on its face serving to contact the moving bobbin assembly, and transfer the energy from the bobbin through the elastomer to the crash stop spring.

Crash stop retainer 1 serves to mount the crash stop assembly to the stationary elements of the voice coil actuator. Crash stop core 2 is attached to the retainer 1 and serves to provide a stop surface to locate movable crash stop ring 5. The crash stop spring 3 is preloaded between the face of ring 5 and an inside shoulder on movable crash stop housing 4. The crash stop assembly extends inside of a cavity in the actuator bobbin 10. Engaging surface 9 serves to engage the crash stop when the motor moves in the direction toward the right, and engaging surface 11 serves to engage the crash stop when the bobbin 10 moves in the direction toward the left.

Ring 5 incorporates a urethane bumper 6 on its contact surface to cushion the shock when the bobbin 10 initially engages ring 5. Similarly, the moving crash stop housing assembly ring section 7 incorporates a urethane bumper 8 on its surface to engage bobbin surface 9.

The urethane bumper rings are tapered in cross section to provide an increasing stiffness as the urethane pad is deformed on contact.

When the actuator 10 moves to the left, then bobbin surface 11 will contact the urethane pad 6 and subsequently force ring 5 to move to the...