Peristaltic driver apparatus
First Claim
1. Peristaltic apparatus for driving an object which comprises:
- a) a pair of members having surfaces facing each other and defining a path; and
b) an actuator between said surfaces and movable along said path, said actuator having a first plurality of clamping sections and a second plurality of pusher sections disposed alternately in successive and linear relationship along said path, the number of said clamping sections being greater by one than the number of said pusher sections and the first and last of said sections in said actuator being clamping sections connectable in driving relationship with said object, said clamping sections being alternately actuated in interleaved pairs, means to simultaneously actuate said interleaved pairs to extend into and release from clamping relationship with said surfaces, two of said pusher sections and a clamping section being disposed between the members of each of said interleaved pairs of said clamping sections.
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Accused Products
Abstract
A peristaltic driver, also known as an Inchworm® actuator using stepping, "clamp-extend-clamp", action of a piezoelectric actuator device provides motion in high resolution (steps) of an object, such as a probe of a scanning probe microscope or other optical, electrical and computer elements. The actuator device is an integral body made up of successive pusher and clamping sections. The clamping sections selectively clamp to members which are spaced from each other. An object is moved along a path between the members by being coupled to a pusher section which is disposed in symmetrical relationship with pairs of other pusher sections and pairs of clamping sections. Voltages are applied across the various sections and provide clamping action without transferring net forces in directions along which the object is pushed, thus reducing motion discontinuities each time the clamping sections extend or retract. The members along which the actuator moves are biased to apply a constant spring pre-load against the clamping members thereby compensating for dimensional changes due to thermal expansion or contraction of the actuator and mechanical wear. Tensile stresses on the piezoelectric material are minimized in that forces are transferred via the clamping sections when they are under compression. In a preferred embodiment, seven sections are used each made of a multiplicity of layers of piezoelectric, ceramic material which are oriented generally paralleling the surfaces of the members for the clamping sections and generally perpendicular to these surfaces for the pusher sections. These sections are interconnected by ceramic material and form a monolithic, integral body.
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Citations
17 Claims
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1. Peristaltic apparatus for driving an object which comprises:
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a) a pair of members having surfaces facing each other and defining a path; and b) an actuator between said surfaces and movable along said path, said actuator having a first plurality of clamping sections and a second plurality of pusher sections disposed alternately in successive and linear relationship along said path, the number of said clamping sections being greater by one than the number of said pusher sections and the first and last of said sections in said actuator being clamping sections connectable in driving relationship with said object, said clamping sections being alternately actuated in interleaved pairs, means to simultaneously actuate said interleaved pairs to extend into and release from clamping relationship with said surfaces, two of said pusher sections and a clamping section being disposed between the members of each of said interleaved pairs of said clamping sections. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for peristaltically advancing an object a desired distance between two parallel surfaces, comprising the steps of:
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a) providing a peristaltic motor having at least seven sections in substantially linear and contiguous array, each section being independently extendable and retractable along its axis to increase and decrease, respectively, its axial length, odd numbered of said sections being clamping sections axially oriented orthogonal to said parallel surfaces, an end one of said clamping sections being also disposed against said object to be advanced, and even numbered of said sections being pusher sections axially oriented parallel to said parallel surfaces; b) extending said third and seventh sections to clamp said motor between said surfaces, said seventh section also being disposed against said object, said third and seventh sections being interleaved with said first and fifth sections; c) thereafter retracting said first and fifth sections; d) thereafter retracting said second section and extending said fourth section to displace said first and fifth sections toward said object to be advanced; e) thereafter extending said first and fifth sections to clamp said motor between said surfaces; f) thereafter retracting said third and seventh sections; g) thereafter retracting said fourth section and extending said sixth section to displace said third and seventh sections to advance said object; and h) thereafter repeating steps b) through h) as many times as needed to advance said object over a desired distance.
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Specification