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Patent Searching and Data


Title:
TILT / VIBRATION SENSOR
Document Type and Number:
WIPO Patent Application WO/2013/096807
Kind Code:
A1
Abstract:
A motion sensing device having an outer wall defining a chamber, the chamber extending between a first end and a second end, a first end plate abutting the first end of the chamber, a first contact extending from said first end plate, a second end plate parallel to said first end plate and abutting said second end of said chamber, a second contact extending from said second end plate, a ring spaced between said first end plate and said second end plate and substantially parallel thereto, said ring partially embedded in said outer wall such that said ring forms an interruption in said outer wall, a ring contact extending from said ring, a ball moveable within said chamber, said ball, first end plate, second end plate and ring each having conductive surfaces which are connected to a circuitry system.

Inventors:
DEL GIUDICE MARK (GB)
VANDERBOSCH KEITH (US)
Application Number:
US2012/071318
Publication Date:
June 27, 2013
Filing Date:
December 21, 2012
Export Citation:
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Assignee:
AMERICAN ELECTRONIC COMPONENTS, INC. (1101 Lafayette Street, Elkhart, IN, 46516, US)
International Classes:
G01C9/06; G01D5/12; G01H1/00; H01H35/02
Foreign References:
JP2003227747A
EP1939911A1
JP2000173420A
US20100000104A1
JP2000331579A
Attorney, Agent or Firm:
JOHNSON, Christopher (105 East Jefferson Boulevard, Suite 400South Bend, IN, 46601-1913, US)
Download PDF:
Claims:
WHAT IS CLAIMED IS:

1. A motion sensing device comprising: an outer wall defining a chamber, said chamber extending between a first end and a second end; a first end plate abutting said first end of said chamber; a first contact extending from said first end plate; a second end plate generally parallel to said first end plate and abutting said second end of said chamber; a second contact extending from said second end plate; a ring spaced between said first end plate and said second end plate and substantially parallel thereto, said ring partially embedded in said outer wall such that a portion of said ring is exposed to said chamber; a ring contact extending from said ring; and a ball moveable within said chamber, said ball, first end plate, second end plate and ring each having conductive surfaces.

2. The motion sensing device of claim 1, wherein said first end plate is partially embedded in said outer wall.

3. The motion sensing device of claim 2, wherein said second end plate is partially embedded in said outer wall.

4. The motion sensing device of claim 1, and said outerwall formed from a first shot and a second shot.

5. The motion sensing device of claim 1, and a gap is defined as the distance between said first end plate and said ring, and a radius is defined as the radius of said ball, wherein said radius is equal to or larger than said gap.

6. A motion sensing device comprising: an outer wall defining a chamber; a first end plate abutting a first end of said chamber; a second end plate abutting a second end of said chamber; a ring spaced between said first end plate and said second end plate; and a ball moveable within said chamber.

7. The motion sensing device of claim 6, wherein said first end plate is partially embedded in said outer wall.

8. The motion sensing device of claim 7, wherein said second end plate is partially embedded in said outer wall.

9. The motion sensing device of claim 6, and said outerwall formed from a first shot and a second shot.

10. The motion sensing device of claim 6, and a gap is defined as the distance between said first end plate and said ring, and a radius is defined as the radius of said ball, wherein said radius is equal to or larger than said gap.

11. The motion sensing device of claim 6, and a second ring spaced between said ring and said second end plate.

12. A motion sensing device comprising: an outerwall defining a chamber; a first end plate abutting a first end of said chamber; a ring spaced from said first end plate by a gap; and a ball movable within said chamber and having a radius; wherein said radius is equal to or greater than said gap.

13. The motion sensing device of claim 12 and a second end plate abutting a second end of said chamber.

14. The motion sensing device of claim 13, and said outerwall is formed from the combination of a first shot and a second shot.

15. The motion sensing device of claim 14, wherein said first end plate is partially embedded in said outerwall.

16. The motion sensing device of claim 15, wherein said second end plate is partially embedded in said outerwall.

17. The motion sensing device of claim 16, wherein said ring is partially embedded in said outerwall.

18. The motion sensing device of claim 17, and said ring extending inwardly of said outerwall.

19. The motion sensing device of claim 12, and a second ring spaced between said ring and said second end plate.

Description:
TILT / VIBRATION SENSOR

BACKGROUND OF THE INVENTION

[0001] Monitoring the movement of objects has wide applicability. In many settings it is important to monitor not only if an object moves, but the nature of the movement, such as tilt, vibration or other movement. Further, objects, such as electronics, are being built on a smaller and smaller scale, consequently the size of the sensor which monitors movement must be designed at a sufficiently small scale to be usable with small-scale objects.

[0002] Sensors for measuring motion, such as tilt and/or vibration, have been present in the market for years. Many sensor designs exist, and most are based on the simple concept of a conductive object, such as a ball, placed in an enclosure, with the ball moving between electrical contacts. The ball is typically formed from, or coated with, a conductive material, such as metal, such that when the ball touches a pair of contacts a circuit is completed, and completion of such circuit provides a signal indicating the movement of the object to which the sensor is attached. When the ball either forms a circuit or breaks a circuit, a signal will be produced indicating that the ball has moved or vibrated which is used as a proxy to indicate that the object the sensor is mounted to has moved or vibrated.

[0003] Many prior art sensors are built in such a way that the sensor includes a rest position, such that the sensor is designed to be placed in a specific orientation (with a specific part of the sensor oriented vertically relative to gravity) when the object the sensor is attached to is at rest. A given amount of deviation from that rest position (the amount of deviation depends on the design of the sensor) causes a signal to be produced which indicates that the object has moved. The failing of such a sensor is that it has limited or no applicability to objects which have no inherent rest position - such as consumer electronics which could be placed in any number of orientations at rest. As an example, a key fob may include a motion sensor. A key fob has no predefined rest position, but could be placed flat on a table, hung from a hook, or stashed in a bag, thereby having no consistent rest position. As such, prior art motion sensors are inadequate as used on objects not having a rest position since such sensors function only when oriented in such rest position.

[0004] As such, an improved tilt/vibration sensor is needed which overcomes these and other failings of the prior art.

SUMMARY OF THE INVENTION

[0005] The tilt/vibration sensor of the present disclosure includes an outer wall defining an inner chamber. A first and second end plate are mounted on opposing ends of the inner chamber. A ring circumscribes the chamber and is located between the end plates. A ball is freely moveable and located within the inner chamber. The ball, end plates and ring are formed from, or plated with, a conductive material. As the sensor moves or vibrates, the ball moves in and out of contact with the end plates and ring causing a circuit to toggle between open and closed, providing a monitorable change of state which indicates that the sensor has moved or vibrated. The sensor of the present invention is manufactured by a multiple-step molding process which partially embeds the end plates and ring in the outer wall.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] A preferred embodiment of this invention has been chosen wherein:

[0007] FIG. 1 is a perspective view of a sensor;

[0008] FIG. 2 is a cross-sectional view of the sensor of FIG. 1 as cut along the line A-A shown in FIG. 3;

[0009] FIG. 3 is an end view of the sensor of FIG. 1 having two end plates and a single ring and housing a ball;

[0010] FIG. 4 is a side view of the sensor of FIG. 1; [0011] FIG. 5 is another end view of the sensor of FIG. 1; [0012] FIG. 6 is a bottom view of the sensor of FIG. 1;

[0013] FIG. 7 is a perspective view of a first shot formed as a preliminary stage in forming the sensor of FIG. 1; [0014] FIG. 8 is a top view the first shot of FIG. 7;

[0015] FIG. 9 is a side view of the first shot of FIG. 7;

[0016] FIG. 10 is a cross-sectional view of the first shot of FIG. 9 as cut along line B-B;

[0017] FIG. 11 is a side view of an end plate;

[0018] FIG. 12 is a side view of a ring with wings removed;

[0019] FIG. 13 is an end view of a sensor having two end plates and two rings and housing a ball;

[0020] FIG. 14 is a side view of the sensor of FIG. 13 ;

[0021] FIG. 15 is an another end view of the sensor of FIG. 13;

[0022] FIG. 16 is a bottom view of the sensor of FIG. 13;

[0023] FIG. 17 is a cross-sectional view of the sensor of FIG. 13 as cut along line C-C;

[0024] FIG. 18 is an end view the first shot formed as a preliminary stage in forming the sensor of FIG. 14;

[0025] FIG. 19 is a perspective view of a section of the first shot of FIG. 18;

[0026] FIG. 20 is a cross-sectional view of a section of the first shot of FIG. 18 as cut along line D-D; and

[0027] FIG. 21 is a bottom view of a section of the first shot of FIG. 18;

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0028] The present disclosure relates to a tilt/vibration sensor 10 which monitors the movement of a monitored object (not shown). Sensor 10 is mounted to, carried on, or carried within the monitored object, such that when the monitored object tilts, vibrates, or otherwise moves, sensor 10 moves with the object. Referring to FIGS. 1-6 sensor 10 includes an outer wall 14 which encloses an inner chamber 16. Chamber 16 includes a first and second end plate 18, 20 spaced at opposing ends of the chamber with a ring 22 spaced between the plates. A moveable object, such as a spherical ball 24, is housed within chamber 16. Sensor 10 is affixed or formed integrally with the monitored object, such that when the monitored object moves or vibrates, sensor 10 also moves or vibrates. When the monitored object tilts, vibrates, or otherwise moves, ball 24 moves within chamber 16 and moves in and out of contact with end plates 18, 20 and ring 22. As ball 24 makes varying contact with end plates 18, 20 and ring 22, circuits are opened and closed thereby providing information about the relative movement of the monitored object.

[0029] Sensor 10 includes an outer wall 14. Together, outer wall 14 and end plates 18, 20 fully enclose chamber 16, as shown in FIG. 2. In the preferred embodiment, outer wall 14 is formed in a two-stage process where a premold (shown in FIGS. 7-10), or first shot 64, is formed in a first stage, and an overmold, or second shot 82, is formed around the first shot in a second stage. As described in greater detail below, ring 22 and end plates 18, 20 are formed integrally with either the first shot 64 or the second shot 82. Together, first shot 64 and second shot 82 form outer wall 14 which defines chamber 16. Outer wall 14 is preferably formed from a polymer, such as by injection molding.

[0030] Referring to FIG. 2, chamber 16 is the hollow interior defined by outer wall 14. Chamber 16 houses ball 24. When the monitored object moves or vibrates, ball 24 moves within chamber 16. Chamber 16 extends between a first end 92 and a second end 94. Chamber has a height H as measured along a plane parallel to end plate 18, 20. In one embodiment, the inner surface 15 of outer wall 14 is generally cylindrically shaped such that chamber 16 is defined as a cylinder with end plates 18, 20 capping the ends of the cylinder. In such embodiment, height H is the inner diameter of the cylinder. In one embodiment, the inner diameter H of the chamber 16 is not constant; inner surface 15 includes a slight draft to accommodate the molding process - in such case, the inner diameter H is measured from the point where the diameter is a minimum.

[0031] End plates 18, 20 abut opposing ends 92, 94 of chamber 16. End plates 18, 20 are configured in a generally parallel relationship with a space formed therebetween defining chamber 16. End plates 18, 20 each include a surface 28, 30 facing the interior of chamber 16. End plates 18, 20 each include a contact 32, 34 extending from plate 18, 20. Contacts 32, 34 serve to connect the end plates 18, 20 to a circuitry system (not shown), as described in greater detail below. As shown in FIG. 1, a portion of end plates 18, 20 may be exposed, in other words the second shot 82 does not completely encase the end plates 18, 20. Opposing ends 92, 94 are formed as part of the second shot 82. [0032] In one embodiment, end plates 18, 20 are formed as generally flat plates, with surface 28, 30 and contacts 32, 34 formed in a single plane, see FIG. 11. In another embodiment, end plates 18, 20 are contoured such that one side of the plate is concave and the opposing side of the plate is convex. In one instance, end plates 18, 20 include a concave surface (not shown) facing chamber 16. In another instance, end plates 18, 20 include a convex surface (not shown) facing chamber 16. The shape of end plates 18, 20 effects the interaction between ball 24 and the end plate. With sensor 10 oriented such that plates 18, 20 are oriented perpendicularly to the direction of gravity, a concave surface encourages ball 24 to rest in contact with one of end plates 18, 20 and out of contact with ring 22 - thereby forming an open circuit in such position. Likewise, a sensor 10 oriented such that plates 18, 20 are oriented perpendicularly to the direction of gravity having convex surfaces urges ball 24 into contact with one of end plates 18, 20 and ring 22 - thereby forming a closed circuit in such position. In such a way, choice of convex or concave surfaces of end plates 18, 20 dictates whether an open or closed circuit is formed when sensor 10 is oriented with plates 18, 20 oriented perpendicularly to the direction of gravity. In any of these embodiments, contact 32, 34 extends from one edge of end plate 18, 20, see FIG. 11. Contact 32, 34 extends from end plate 18, 20 through outer wall 14 and out of sensor 10 where they are integrated with the circuitry system, as described in further detail below.

[0033] Ring 22 is spaced between the end plates 18, 20 in chamber 16. Ring 22 is a generally flat plate which includes a generally circular aperture 44 having an inner diameter I formed through the middle of the ring, see FIG. 12. Ring 22 includes a first face 88 and a second face 90 which are generally planar, parallel faces of the ring. Ring 22 has a thickness T defined as the distance between first face 88 and second face 90, as shown in FIG. 2. Ring 22 includes one or more contact 46 extending from the ring through outer wall 14. In the preferred embodiment, contact 46 extends radially outward from ring 22, though the contact may extend in other directions within the spirit of this disclosure.

[0034] Referring to FIG. 2, in the preferred embodiment, ring 22 extends inwardly from inner surface 15 of outer wall 14, such that ring 22 forms an interruption in the outer wall between end plates 18, 20; inner diameter I of ring is preferably less than height H of chamber 16. With ring 22 inwardly extending from inner surface 15 of outer wall 14, ball 24 is held inward from outer wall 14. Ball 24 is preferably sized to be larger than a gap G formed between end plate 18, 20 and ring 22. Ball 24 preferably has a radius R which is greater than gap G, such that when the ball is in contact with one of end plates 18, 20, the ball does not contact outer wall 14 of chamber 16. In the preferred embodiment, the gap G between end plate 18 and ring 22 is substantially the same distance as the gap G between end plate 20 and ring 22, as measured from the end plate surface to the nearest portion of ring 22 to the respective endplate. Ring 22 circumscribes outer wall 14 between end plates 18 and 20. Outer wall 14 is preferably formed from a non-conductive material, such as plastic. As such, by having ring 22 extend inwardly from outer wall 14, ball 24 is held away from the outer wall, and out of contact with the outer wall.

[0035] Referring now to FIGS. 14-22, in one embodiment, two or more rings 22 are spaced between end plates 18, 20. Using multiple rings 22 allows for increased sensitivity of detection of the movement and relative position of ball 24 within chamber 16. A first ring 22 includes one or more contact 46 connecting each ring to the circuitry system. A second ring 23 includes one or more contact 47. The circuitry system is integrated with contacts 46, 47 in such a way that it can distinguish between ball 24 contacting the first ring 22 or the second ring 23, thereby providing improved positional information about ball 24 within chamber 16. In such

embodiment, a pair of first shots 96, 98 are formed, with first ring 22 embedded in first shot 96 and second ring 23 embedded in first shot 98. It is noted that the geometry of first shot 96 is identical to the geometry of second shot 98. End plate 18 is nested against first shot 96, end plate 20 is nested against first shot 98, and first shot 96 and first shot 98 are placed side by side in a mold, which mold is used to form second shot 100 which holds the first shots 96, 98 and the end plates 18, 20 together as sensor 10.

[0036] Contacts 32, 34, 46 are elements of a circuitry system such that as ball 24 moves within chamber 16, circuits close and open as the ball contacts and moves out of contact with plates 18, 20 and ring 22. The circuitry system monitors the signals received from plates 18, 20 and ring 22 and processes the signals into useable data to identify when the monitored object has tilted, vibrated or otherwise moved. In one embodiment, the circuitry system is an element of the electrical system of the monitored object. [0037] Ball 24, end plates 18, 20, ring 22 and attached contacts 32, 34, 46 are preferably formed from a conductive material, such as metal. Alternatively, ball 24, end plates 18, 20, ring 22 and attached contacts 32, 34, 46 are plated with a conductive material, such as metal, preferably gold. The materials and construction of ball 24, end plates 18, 20, ring 22 and attached contacts 32, 34, 46 may vary within the scope of this description.

[0038] Ball 24 is a spherical movable object having a radius R and located within chamber 16. Ball 24 is freely movable within chamber 16, such that as the monitored object moves or vibrates, ball 24 will also move or vibrate in reaction to the movement of the monitored object. A conductive member is defined as one of end plates 18, 20 or ring 22. When ball 24 contacts two conductive members 50, a closed circuit is formed by the ball forming a conductive bridge connecting the two conductive members. A finite number of circuit combinations are possible, with a circuit combination defined as ball 24 contacting two conductive members 50. In the case where chamber 16 includes first end plate 18, a single ring 22, and second end plate 20, there are two possible circuit combinations: (1) first end plate 18 - ball 24 - ring 22 and (2) ring 22 - ball 24 - second end plate 20. One of ordinary skill in the art will appreciate that when two rings 22 are included in chamber 16 that additional circuit combinations will be possible. In addition to the circuit combinations, as ball 24 moves within chamber 16, ball 24 may alternatively be in an open circuit position defined by the ball contacting zero or one conductive member at any given time. The circuitry system registers when ball 24 moves between: (1) one circuit combination and another circuit combination; (2) between a circuit combination and an open circuit position; or (3) between an open circuit position and a circuit combination; each of these movements registers as a ball movement by the circuitry system and indicates movement of the monitored object.

[0039] In the preferred embodiment, sensor 10 is oriented relative to the monitored object with ring 22 and end plates 18, 20 in a substantially vertical orientation. With ring 22 and end plates 18, 20 in a vertical orientation, ball 24 will rest on ring 22 and will roll between end plates 18, 20 depending on the movement of the monitored object to which the sensor 10 is attached. The monitored object may be subjected to movement (linear and rotational) in three dimensions, and sensor 10 will provide a signal to the circuitry system to indicate such movement. [0040] Ball 24 preferably is sized to be large enough that the ball cannot settle in gap G, such that for any position of ball 24 within chamber 16 a portion of ball 24 is always intersected by a plane passing through one of faces 88, 90 of ring 22. Preferably, ball 24 is sized to nearly fill chamber 16, such that for any position of ball 24 within chamber 16, a plane which is parallel to face 88, 90 and is intersecting a great circle of ball 24 is positioned between faces 88, 90.

[0041] Sensor 10 is preferably formed in a two-stage molding process. In the first stage, ring 22 is placed in a first mold (not shown) and a material, such as plastic, is injected around the ring to form a first shot 64 as described in detail below. In the preferred embodiment, ring 22 includes a contact 46 extending radially from the ring, and a pair of support members 66 extending radially from opposing edges of the ring and generally perpendicular to contact 46, though the orientation may vary. Support members 66 are for supporting and positioning ring 22 within the first mold and alternatively include wing members (not shown) for additional support and positioning assistance within the first mold. The wing members are extensions of support members 66, and preferably extend perpendicularly from the support members, though the orientation may vary within the scope of this disclosure.

[0042] First shot 64 is shaped to allow a second shot 82 to be formed around the first shot. First shot 64 is formed having a surrounding wall 80 which is a generally ring-shaped wall extending axially away from ring 22 and terminates in an outer face 76, 77. Outer face 76 is generally planar and parallel with ring 22 and annularly-shaped. In one embodiment, first shot 64 includes a guide 72 extending axially away from outer surface 76 of ring 22. First shot 64 preferably includes a plurality of guides 72 extending axially from outer face 76 and spaced radially around a recess 74, 75. First shot 64 includes two outer faces 76, 77 which are parallel to one another and are spaced in opposite directions from ring 22. Each of outer faces 76, 77 includes a recess 74, 75. Recess 74, 75 is an annularly-shaped plane generally parallel with outer face 76, 77 and stepped inwardly therefrom in the direction of ring 22. Recess 74, 75 is shaped to allow one of end plates 18, 20 and the respective contact 32, 34 to be seated inward from outer edge 76 of first shot 64 and to orient the end plate substantially parallel to, and at a spaced distance from, ring 22. Guide 72 is preferably tapered such that it slopes toward recess 74 and is formed to abut the inner diameter of outer face 76 such that as end plate 18, 20 is advanced toward recess 74, guide 72 directs the end plate into the recess. First shot 64 preferably includes one or more flared sections 78 extending outward from the surrounding wall 80.

[0043] Second shot 82 is formed around first shot 64 and end plates 18, 20. Prior to forming second shot 82 ball 24 is placed in chamber 16, first end plate 18 is nested in first recess 74, and second end plate 20 is nested in second recess 75. First shot 64 with end plates 18, 20 are placed in a second mold (not shown) where second shot 82 is molded around first shot 64 and end plates 18, 20. The outer shape of second shot 64 may vary within the scope of this disclosure. Second shot 82 is overmolded over first shot 64, but may be a partial overmold as portions of first shot or end plates 18, 20 may be visible in the final product. Techniques for injection molding, and overmolding specifically, are well known in the art, and the present disclosure may be adapted within the spirit of this disclosure to conform to varying injection molding techniques.

[0044] Sensor 10, as formed from first shot 64, second shot 82, ring 22 and end plates 18, 20, may have an outer shape which meets the needs of the end user. In FIG. 1, sensor 10 is shown as being generally box-shaped with the contacts 46, 32, 34 from ring 22 and end plates 18, 20 extending from one face of the box in a linear pattern - such design may be convenient where the sensor is mounted directly to a circuit board with contacts 46, 32, 34 integrated with the board. Alternatively, the outer form of sensor 10 and the direction of protrusion of contacts 46, 32, 34 may vary according to the geometry dictated by the monitored object in which the sensor is housed.

[0045] In an alternative embodiment, first shot 64 is formed around both ring 22 and end plate 18. In such embodiment, first shot 64 includes a single recess 74 in which end plate 20 is seated prior to formation of second shot 82. In such embodiment, end plate 18 includes a pair of contacts 32 extending radially from the plate and from opposing edges of the plate - a pair of contacts are included to support end plate 18 during the formation of first shot 64.

[0046] In one embodiment, each of end plates 18, 20 and ring 22 are formed as a chain of plates or rings such that a series of sensors may be formed on the chain and then separated in a post-processing step.

[0047] In another embodiment, second shot 82 is formed by heat staking peripheral portions of first shot 64 such that one or both of end plates 18, 20 is secured to first shot 64 by heating the peripheral portion until it deforms around end plate 18, 20 thereby holding the end plate(s) in place by interference fit.