# US 2014/0194241 A1 · Bidirectional MEMS Driving Arrangement

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- Number: US 2014/0194241 A1
- Document ID: US20140194241A1
- Status: Published application
- Kind: A1
- Application number: 13/735,211
- Filed: 2013-01-07
- Published: 2014-07-10
- Earliest claimed: 2013-01-07
- Assignees: Timex Group USA, Inc.
- Applicants: Timex Group USA, Inc.
- Inventors: Gerhard Stotz
- Web page: https://patentgrep.com/patent/US20140194241A1

## CPC

- F16H 1/32: in which the central axis of the gearing lies inside the periphery of an orbital gear
- G04C 3/12: driven by piezoelectric means; driven by magneto-strictive means
- B81B 5/00: Devices comprising elements which are movable in relation to each other, e.g. comprising slidable or rotatable elements
- B81B 2203/056: Rotation in a plane parallel to the substrate
- F16H: GEARING
- G04C: ELECTROMECHANICAL CLOCKS OR WATCHES
- B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00)

## Abstract

A micro-electromechanical system (MEMS) driving arrangement comprising a driven wheel comprising (n) teeth about an outer periphery thereof, an actuator ring around the driven wheel, itself comprising (n)+(x) teeth about an inner periphery thereof, wherein the (n)+(x) teeth of the actuator ring progressively engage and disengage subsets of the (n) teeth of the driven wheel; a driving actuation assembly, coupled to the actuator ring, for driving the actuator ring in a hysteresis-type motion so as to cause rotation of the driven wheel, wherein after one full cycle of engagements and disengagements between selective subsets of the (n) teeth of the driven wheel with selective subsets of the (n)+(x) teeth of the actuator ring, the driven wheel rotates by (x) teeth corresponding to [(360)(x)/(n)]°.

## Claims

### Claim 1

A micro-electromechanical systems (MEMS) driving arrangement for an electronic device, the micro-electromechanical systems (MEMS) driving arrangement comprising:
a driven wheel having a diameter, comprising (n) teeth about an outer periphery thereof, wherein (n) is a positive integer;
an actuator ring having an inner diameter that is greater than the diameter of the driven wheel, comprising (n)+(x) teeth about an inner periphery thereof and wherein (x) is an integer of at least 1; wherein subsets of the (n)+(x) teeth of the actuator ring progressively engage and disengage subsets of the (n) teeth of the driven wheel;
a driving actuation assembly, coupled to the actuator ring, for driving the actuator ring in a hysteresis-type motion so as to cause rotation of the driven wheel, the driving actuation assembly comprising:
a first driving actuator coupled to the actuator ring for selectively pulling the actuator ring in a first direction and pushing the actuator ring in a direction opposite the first direction thereby causing subsets of the (n)+(x) teeth of the actuator ring to engage and disengage subsets of the (n) teeth of the driven wheel;
a second driving actuator coupled to the actuator ring for selectively pulling the actuator ring in a second direction and pushing the actuator ring in a direction opposite the second direction, wherein the first direction is perpendicular to the second direction, thereby causing the (n)+(x) teeth of the actuator ring to engage and disengage subsets of the (n) teeth of the driven wheel;
wherein after a full cycle of engagements and disengagements between selective subsets of the (n) teeth of the driven wheel with selective subsets of the (n)+(x) teeth of the actuator ring, the driven wheel rotates [(360)(x)/(n)]°.

### Claim 2 (depends on 1)

The micro-electromechanical systems (MEMS) driving arrangement as claimed in claim 1, wherein a full cycle of engagements and disengagements between selective subsets of the (n) teeth of the driven wheel with selective subsets of the (n)+(x) teeth of the actuator ring comprises:
causing the actuator ring to move from an initial position where both the first driving actuator and the second driving actuator are each respectively pushing the actuator ring so that a subset of the (n)+(x) teeth of the actuator ring is meshing with a subset of the (n) teeth of the driven wheel to a next position due to the first driving actuator, and thereafter, pulling the actuator ring and having the second driving actuator continue pushing the actuator ring so that a different subset of the (n)+(x) teeth of the actuator ring are meshing with a different subset of the (n) teeth of the driven wheel to a then next position due to both the first driving actuator and second driving actuator each respectively pulling the actuator ring so that yet a different subset of the (n)+(x) teeth of the actuator ring are meshing with a different subset of the (n) teeth of the driven wheel and thereafter to a then next position due to the first driving actuator pushing the actuator ring and the second driving actuator continuing to pull the actuator ring so that yet a different subset of the (n)+(x) teeth of the actuator ring are meshing with a different subset of the (n) teeth of the driven wheel and finally, back to the initial position due to both the first driving actuator and the second driving actuator each respectively pushing the actuator ring so that yet a different subset of the (n)+(x) teeth of the actuator ring are meshing with a different subset of the (n) teeth of the driven wheel.

### Claim 3 (depends on 1)

The micro-electromechanical systems (MEMS) driving arrangement as claimed in claim 1, wherein (n) is in the range of about 300 to about 1000 and (x) is in range of 1 to 4, inclusive.

### Claim 4 (depends on 1)

The micro-electromechanical systems (MEMS) driving arrangement as claimed in claim 1, wherein the driven wheel is driveable in both the clockwise and counterclockwise direction by the driving actuation assembly, and the driving actuation assembly comprises only two driving actuators.

### Claim 5 (depends on 4)

The micro-electromechanical systems (MEMS) driving arrangement as claimed in claim 4, wherein at least a subset of the (n)+(x) teeth of the actuator ring is always meshing with a subset of the (n) teeth of the driven wheel.

### Claim 6 (depends on 1)

The micro-electromechanical systems (MEMS) driving arrangement as claimed in claim 1, wherein at least a subset of the (n)+(x) teeth of the actuator ring is always meshing with a subset of the (n) teeth of the driven wheel.

### Claim 7 (depends on 1)

The micro-electromechanical systems (MEMS) driving arrangement as claimed in claim 1, wherein each of the first and second driving actuators comprises:
a driving element extending outwardly from a mobile part; and
at least a first arm of a first length and at least a second arm spaced from the at least first arm and of a length different from the first length, wherein each of the at least first arm and second arm comprises:
a first end coupled to the driving element; and
a distal end connected to the actuator ring.

### Claim 8 (depends on 7)

The micro-electromechanical systems (MEMS) driving arrangement as claimed in claim 7, wherein the driving element is one of linear, L-shaped or T-shaped.

### Claim 9

A method of driving a driven wheel in a micro-electromechanical systems (MEMS) driving arrangement for an electronic device, wherein the micro-electromechanical systems (MEMS) driving arrangement comprises a driven wheel having a diameter, comprising (n) teeth about an outer periphery thereof, wherein (n) is a positive integer; an actuator ring having an inner diameter that is greater than the diameter of the driven wheel, comprising (n)+(x) teeth about an inner periphery thereof and wherein (x) is an integer of at least 1; wherein the (n)+(x) teeth of the actuator ring progressively engage and disengage subsets of (n) teeth of the driven wheel; a driving actuation assembly, coupled to the actuator ring, for driving the actuator ring in a hysteresis-type motion so as to cause rotation of the driven wheel, wherein the driving actuation assembly comprises a first driving actuator coupled to the actuator ring and a second driving actuator coupled to the actuator ring, wherein the method comprises the steps of:
selectively pulling the actuator ring in a first direction and selectively pushing the actuator ring in a direction opposite the first direction with the first driving actuator thereby causing selected subsets of (n)+(x) teeth of the actuator ring to engage and disengage subsets of the (n) teeth of the driven wheel;
selectively pulling the actuator ring in a second direction and selectively pushing the actuator ring in a direction opposite the second direction with the second driving actuator thereby causing selected subsets of (n)+(x) teeth of the actuator ring to engage and disengage subsets of the (n) teeth of the driven wheel;
wherein:
the first direction is perpendicular to the second direction; and
after a full cycle of engagements and disengagements between selective subsets of the (n) teeth of the driven wheel with selective subsets of the (n)+(x) teeth of the actuator ring, the driven wheel rotates [(360)(x)/(n)]°.

### Claim 10 (depends on 9)

The method as claimed in claim 9, comprising the steps of:
causing the actuator ring to move from an initial position where both the first driving actuator and the second driving actuator are each respectively pushing the actuator ring so that a subset of the (n)+(x) teeth of the actuator ring is meshing with a subset of the (n) teeth of the driven wheel to a next position due to the first driving actuator; and
thereafter pulling the actuator ring and having the second driving actuator continue pushing the actuator ring so that a different subset of the (n)+(x) teeth of the actuator ring are meshing with a different subset of the (n) teeth of the driven wheel to a then next position due to both the first driving actuator and second driving actuator each respectively pulling the actuator ring so that yet a different subset of the (n)+(x) teeth of the actuator ring are meshing with a different subset of the (n) teeth of the driven wheel; and
thereafter to a then next position due to the first driving actuator pushing the actuator ring and the second driving actuator continuing to pull the actuator ring so that yet a different subset of the (n)+(x) teeth of the actuator ring are meshing with a different subset of the (n) teeth of the driven wheel; and
finally, back to the initial position due to both the first driving actuator and the second driving actuator each respectively pushing the actuator ring so that yet a different subset of the (n)+(x) teeth of the actuator ring are meshing with a different subset of the (n) teeth of the driven wheel.

### Claim 11 (depends on 9)

The method as claimed in claim 9, including the step of maintaining a continuous meshing of at least one or more of the (n)+(x) teeth of the actuator ring with one or more of the (n) teeth of the driven wheel throughout at least one full cycle of engagements and disengagements such that the driven wheel has rotated [(360)(x)/(n)]°.