US 5,332,942 AGranted

Inchworm actuator

OwnerBrian G. Rennexinventor

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Abstract

This invention relates to inchworm linear motors or piezoelectric linear actuators and in particular to designs which address difficulties associated with miniaturization, the primary one being that the clamping driver is typically oriented laterally to the drive direction and when the lateral dimension becomes very small there is not sufficient displacement of the clamping driver to allow a practical clamping. That is, the tolerance required for the device dimensions would then be prohibitively small. This problem is overcome by orienting the clamping drivers longitudinally, i.e. parallel, to the drive direction, thereby permitting the length of said clamping drivers to be significantly greater than for the prior art case of lateral orientation. An additional feature re-directs the longitudinal clamp-drive to a lateral direction for clamping of the driven element.

Claims27

Dependent claims

An inchworm actuator comprising:

a driven element,
a driver base,
a driver assembly comprising a driver actuator, wherein said driver actuator has a length that is greater than its width or depth, wherein said driver actuator is oriented so that said driver actuator length is parallel to the direction in which said driven element is driven, wherein a bottom end of said driver actuator is fixedly attached to said driver base,
a moving clamp assembly comprising a moving clamp actuator, a moving clamp, and a moving clamp support fixedly attached at its top end to the top of said driver actuator, wherein said moving clamp actuator has a length that is greater than its width or depth, wherein said moving clamp actuator is oriented so that said moving clamp actuator length is parallel to the direction in which said driven element is driven, wherein the bottom of said moving clamp actuator is fixedly attached to the bottom of said moving clamp support, wherein said moving clamp is attached to the top of said moving clamp support, wherein said moving clamp actuator drives said moving clamp to clamp said driven element,
a second clamp assembly, the bottom of which is fixedly attached to said driver base, wherein said second clamp assembly has a length that is greater than its widths or depths, wherein said second clamp assembly is oriented so that said length is parallel to the direction in which said driven element is driven, wherein said second clamp assembly may be activated to clamp said driven element, and
a wiring system for activation of said driver actuator, said moving clamp actuator, and said second clamp assembly for driving said inchworm actuator to expand or contract, wherein said expansion occurs when the following actuator stroke cycle is enacted:
in a first period of time said second clamp assembly releases said driven element and said moving clamp assembly engages said driven element, at which time said driver actuator changes length to drive said moving clamp assembly and said driven element in an expanding direction;
and in a second period said moving clamp assembly releases said driven element at which time said second clamp assembly engages said driven element, after which time said driver actuator undergoes its return stroke in the direction of contraction, wherein said contraction occurs when the following actuator stroke cycle is enacted:
in a first period of time said second clamp assembly releases said driven element and said moving clamp assembly engages said driven element, at which time said driver actuator changes length to drive said moving clamp assembly and said driven element in a contracting direction;
and in a second period said moving clamp assembly releases said driven element at which time said second clamp assembly engages said driven element, after which time said driver actuator undergoes its return stroke in the direction of expansion.

7 more elements

An inchworm-actuator valve comprising:

a tube,
support tabs located within said tube,
a nozzle seat located a distance above said support tabs within said tube,
an inchworm actuator further comprising:
a driven nozzle,
a driver base fixedly attached to said support tabs,
a driver assembly comprising a driver actuator, wherein said driver actuator has a length that is greater than its width or depth, wherein said driver actuator is oriented so that said driver actuator length is parallel to the direction in which said driven nozzle is driven, wherein a bottom end of said driver actuator is fixedly attached to said driver base,
a moving clamp assembly comprising a moving clamp actuator, a moving clamp, and a moving clamp support fixedly attached at its top end to the top of said driver actuator, wherein said moving clamp actuator has a length that is greater than its width or depth, wherein said moving clamp actuator is oriented so that said moving clamp actuator length is parallel to the direction in which said driven nozzle is driven, wherein the bottom of said moving clamp actuator is fixedly attached to the bottom of said moving clamp support, wherein said moving clamp is attached to the top of said moving clamp support, wherein said moving clamp actuator drives said moving clamp to clamp said driven nozzle,
a second clamp assembly, the bottom of which is fixedly attached to said driver base, wherein said second clamp assembly has a length that is greater than its widths or depths, wherein said second clamp assembly is oriented so that said length is parallel to the direction in which said driven nozzle is driven, wherein said second clamp assembly may be activated to clamp said driven nozzle, and
a wiring system for activation of said driver actuator, said moving clamp actuator, and said second clamp assembly for driving said inchworm actuator to expand or contract, wherein said expansion occurs when the following actuator stroke cycle is enacted:
in a first period of time said second clamp assembly releases said driven nozzle and said moving clamp assembly engages said driven nozzle, at which time said driver actuator changes length to drive said moving clamp assembly and said driven nozzle in an expanding direction;
and in a second period said moving clamp assembly releases said driven nozzle at which time said second clamp assembly engages said driven nozzle, after which time said driver actuator undergoes its return stroke in the direction of contraction, wherein said contraction occurs when the following actuator stroke cycle is enacted:
in a first period of time said second clamp assembly releases said driven nozzle and said moving clamp assembly engages said driven nozzle, at which time said driver actuator changes length to drive said moving clamp assembly and said driven nozzle in a contracting direction;
and in a second period said moving clamp assembly releases said driven nozzle at which time said second clamp assembly engages said driven nozzle, after which time said driver actuator undergoes its return stroke in the direction of expansion, wherein said driven nozzle can be driven into said nozzle seat to block any fluid flow through said tube.

11 more elements

Dependencies are inferred from the claim text.