Shutter assembly with drive ring-mounted magnet

A shutter assembly includes a drive ring having a permanent magnet disposed thereon. The shutter assembly also includes a solenoid defining a gap between first and second magnetic poles thereof, the drive ring being disposed coplanar with the solenoid and being rotatable in response to a magnetic field created between the first and second magnetic poles. The shutter assembly also includes a plurality of shutter blades configured to transition between an open position and a closed position in response to rotation of the drive ring. The shutter assembly further includes a base plate separating the plurality of shutter blades from at least one of the drive ring and the solenoid.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to shutter assemblies and more particularly to photographic-type shutter assemblies that rely on electromagnetic forces to open and close.

2. Description of Related Art

Electrically operated lens shutters used in various types of photographic and laboratory equipment are well known in the art. Lens shutters especially adapted for high speed opening and closing can operate in fractions of a second. An open/close cycle can take place in 30-40 milliseconds or less and repeated cycles at frequencies of 30 cycles per second are common.

Lens shutters generally are of two types. In one type, a so-called “guillotine” shutter has one or two thin, metal blades or leaves arranged to cover a lens opening. Pivot connections allow each blade to swing between a closed position where the blades cover the lens opening and an open position where the blades are drawn aside from the lens opening.

In a second type of shutter, a plurality of pivotally mounted blades are arranged around the lens opening. Each blade is connected to a rotatable drive ring. In the operation of these shutters, the rotation of the drive ring in one direction causes the blades to swing in unison to an open position. Counter rotation of the ring swings the blades to a closed position over the lens opening after exposure. Generally a linear electric motor is used to activate the shutter. When activated, the linear motor pulls on a lever arm that rotates the drive ring to open the shutter. To close the shutter the motor is deactivated and a spring causes the counter rotation of the drive ring to close the shutter. As noted above, shutters of this sort can cycle open and close 30 times per second.

In some applications, however, space is limited. Space limitations, particularly in the region of the shutter opening, dictate the parameters of size and placement of components for opening and closing the shutter. For example, components placed near the shutter opening must have a relatively low profile so as not to interfere with the cone angle of the light passing through the open shutter. Space limitations also complicate the substitution of one shutter assembly for another as in changing shutter size while maintaining the same base structure.

As noted above, existing shutter assemblies typically mechanically couple a linear electric motor to the shutter for opening and closing the lens opening. However, for proper operation, particularly at high speeds, the mechanical linkage must be precisely made and the movement of the linkage must be dampened by relatively large dampening assemblies.

Alternatively, other known shutter assemblies may utilize electromagnetic energy to open and close the shutter. For example, such assemblies may include a permanent magnet disposed on a drive ring and a pair of spaced solenoids disposed above the permanent magnet. A polarity of an operative end of the first solenoid can be opposite that of an operative end of the second solenoid, such that the permanent magnet is attracted to one of the solenoids and repelled by the other. The solenoids can be energized to switch polarities, to effectuate a movement of the permanent magnet between a first position proximate the first solenoid and a second position proximate the second solenoid.

Such assemblies may be configured to open and close shutters at relatively high speeds without damaging the shutter blades. However, such assemblies generally require that the solenoid be situated in a tier or layer of the shutter assembly separate from, and either above or below, the permanent magnet. This necessarily increases the overall thickness of the shutter assembly.

Accordingly, the disclosed system and method are directed towards overcoming one or more of the problems set forth above.

BRIEF SUMMARY OF THE INVENTION

In an exemplary embodiment of the present disclosure, a shutter includes at least one shutter blade, a magnet movably connected to the at least one shutter blade, and a solenoid defining a gap between a first pole and a second pole. The solenoid is configured to controllably draw the magnet into the gap in a first state and to controllably repel the magnet from the gap in a second state.

In another exemplary embodiment of the present disclosure, a shutter includes a plurality of shutter blades moveable between an open position and a closed position, a magnet movably connected to each shutter blade of the plurality of shutter blades, and a solenoid having a first face defining a first pole, and a second face facing the first face and defining a second pole. The first and second faces lie in a plane substantially parallel to the plurality of shutter blades and the solenoid defines a central axis perpendicular to the plane. The magnet is configured to move in a path coplanar with the solenoid and substantially perpendicular to the central axis in response to a polarity of at least one of the first and second poles.

In a further exemplary embodiment of the present disclosure, a method of controlling a shutter includes drawing a portion of a magnet into a gap defined by first and second poles of a solenoid. Drawing the portion of the magnet into the gap causes a plurality of shutter blades movably connected to the magnet to move to an open position. The method also includes repelling the portion of the magnet from the gap. Repelling the portion of the magnet from the gap causes the plurality of shutter blades to move to a closed position.

In a further exemplary embodiment of the present disclosure, a shutter assembly includes a drive ring having a permanent magnet disposed thereon and a solenoid defining a gap between first and second magnetic poles thereof. In such an exemplary embodiment, the drive ring is disposed coplanar with the solenoid and is rotatable in response to a magnetic field created between the first and second magnetic poles. In such an exemplary embodiment, the shutter assembly also includes a plurality of shutter blades configured to transition between an open position and a closed position in response to rotation of the drive ring, and a base plate separating the plurality of shutter blades from at least one of the drive ring and the solenoid.

In yet another exemplary embodiment of the present disclosure, a method of controlling a plurality of shutter blades includes providing a shutter assembly including a drive ring having a permanent magnet disposed thereon, and a solenoid defining a gap between first and second magnetic poles thereof. The drive ring is disposed coplanar with the solenoid and is rotatable in response to a magnetic field created between the first and second magnetic poles. The shutter assembly also includes a plurality of shutter blades configured to transition between an open position and a closed position in response to rotation of the drive ring. The shutter assembly further includes a base plate separating the plurality of shutter blades from at least one of the drive ring and the solenoid. In such an exemplary embodiment, the method of controlling a plurality of shutter blades further includes transitioning the plurality of shutter blades between the open and closed positions and reducing an electrical signal applied to the solenoid while the plurality of shutter blades is in transit between the open and closed positions.

In still another exemplary embodiment of the present disclosure, a shutter assembly includes a solenoid, a drive ring disposed coplanar with the solenoid and configured to rotate in response to activation of the solenoid, and a plurality of shutter blades configured to transition between an open position and a closed position in response to rotation of the drive ring.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows a shutter10according to an exemplary embodiment of the present disclosure. The shutter10is a type that can be used in any photographic, scientific or calibration application that requires one or more cycles of opening and closing of a shutter opening by driving one or more shutter blades across an opening.

The shutter10includes a base plate12defining a shutter opening14. In an exemplary embodiment, the shutter opening14is a circular aperture having a central axis36. Light is selectively occluded from passing through and is allowed to pass through the shutter opening14by moving a plurality of shutter blades16(usually five) in a pivoting action across the shutter opening14. The shutter blades16preferably all move in a single shutter plane, which is normal to the central axis36of the shutter opening14. In prior art shutters, the shutter blades are operated by a linear motor mounted to the base plate. The motor acts through a mechanical linkage to rotate a driver plate or drive ring, wherein the rotation of the driver plate in a to-and-fro motion acts to move the shutter blades to selectively reveal and cover the shutter opening.

An exemplary shutter10of the present disclosure also uses a drive ring18such as those conventionally used. A portion of the drive ring18is seen inFIG. 1through the removed portion of the base plate12. The drive ring18has an opening20that aligns with the shutter opening14so as not to impinge on the shutter opening. Extending from the drive ring are pins (not shown) that extend into a corresponding cam slot (not shown) formed in each of the shutter blades16. With this arrangement, the rotation of the drive ring18to and fro about a drive ring rotational axis that is co-linear with the central axis36of the lens opening14will cause the shutter blades16to pivot between open and closed positions. The closed position is shown inFIG. 1.

As also shown inFIG. 1, the shutter10includes a permanent magnet24in communication with the drive ring18, and a solenoid26arranged proximate the permanent magnet24. The permanent magnet24and the solenoid26preferably cooperate to actuate the drive ring18about the drive ring rotational axis discussed above.

The solenoid26generally is made up of a wire28wound about a core30. In the exemplary embodiment illustrated inFIG. 1, the solenoid26is generally arcuate and has an inner diameter larger than the diameter of the shutter opening. Accordingly, the solenoid26can be disposed in the shutter10about the shutter opening14without interfering with the shutter opening14. In an exemplary embodiment of the present disclosure, the solenoid26can be substantially C-shaped and may span more than about 270-degrees of rotation about the central axis36. The substantial C-shape terminates at operative faces32a,32b. The operative faces32a,32bare spaced by a gap34because the solenoid26does not form a complete circle around the shutter opening36. At least a portion of the permanent magnet24preferably is disposed in the gap34between the first and second operative faces32a,32b. Ends of the wire28forming the solenoid26are disposed as leads proximate the first and second operative faces32a,32b, and the leads are connected to a solenoid driver38. When the driver38applies a current to the solenoid26via the wire28, the operative faces32a,32bbecome oppositely polarized. More specifically, when a first current is applied to the solenoid26, the first operative face32atakes on a first polarity, i.e., a north or south polarity, and the second operative face32btakes on an opposite polarity.

The permanent magnet24preferably is mounted to the drive ring18, and at least a portion of the magnet24preferably is disposed in the gap34formed between the first and second operative faces32a,32bof the solenoid26. As illustrated inFIG. 2, the permanent magnet24is arranged with its polar axis25, i.e., the axis through both the first and second poles of the permanent magnet24, substantially parallel to the central axis36. In the illustrated exemplary embodiment, the north pole of the magnet24is arranged above the south pole, and the north pole is disposed in the gap34between the first and second operative faces32a,32bof the solenoid26. The south pole may be disposed away from the gap34, below the solenoid26.

In operation and with the shutter10in a closed position as shown inFIGS. 1 and 2, the magnet24may be attracted to and may be generally aligned adjacent the first operative face32a. When a first current is applied to the solenoid26, a north pole is created at the first operative face32aof the solenoid26and a south pole is created at the second operative face32b. Because the north pole of the permanent magnet24is disposed between the operative faces32a,32bof the solenoid26, the magnet24will be repelled by the first operative face32a, and will be attracted by the second operative face32b, thereby moving from a position proximate the first operative face32ato a position proximate the second operative face32b. Such movement is illustrated by arrow44. Because the permanent magnet24is connected to the drive ring18, movement of the magnet24drives the drive ring18about the drive ring rotation axis to open the shutter blades16. Once the shutter blades16open, light is permitted to pass through the shutter opening14.

De-energizing the solenoid26will allow the shutter blades16to remain in an open position until the current applied to the solenoid26is reversed because the permanent magnet24will continue to be attracted to the second operative face32b. Accordingly, to close the shutter blades16, and thereby occlude light through the shutter opening14, the driver38can be operated to reverse the polarity of the solenoid26. Reversing the polarity may form a north pole at the second operative face32b, thereby repelling the permanent magnet24away from the second operative face32b. Reversing the polarity may also form a south pole at the first operative face32aand may attract the permanent magnet24thereto. Movement of the magnet from the second operative face32bto the first operative face32ais illustrated by arrow46.

As should be understood, delaying the reversal of the current will allow the shutter10to remain in the open position for the time of the delay. Conversely, reversing the current soon after opening will cause the shutter10to open and close quickly.

In an exemplary embodiment to the present disclosure, the motion of the drive ring18may be stopped when the permanent magnet24contacts one of the first and second operative faces32a,32bof the solenoid26. Appropriate sizing of the gap34and of the permanent magnet24will ensure that contact prevents over-rotation of the drive ring18past the fully-closed or the fully-open positions of the shutter blades16. Alternatively, the shutter10may include other mechanical stops or abutting surfaces that stop rotation of the drive ring18.

The shutter10may also include a damper to avoid slamming of components into each other. For example, when the permanent magnet24is to be moved between the open and closed positions, the movement of the permanent magnet24could be slowed by alternating the current applied to the solenoid26, for example, to alternately attract and repel the permanent magnet24as it approaches one of the operative faces32a,32b. For example, as the magnet24is about to contact one of the operative faces32a,32b, a pulse could be applied to the solenoid26to repel the permanent magnet24to slow the movement of the permanent magnet24, thereby acting on the permanent magnet24as a magnetic brake.

As discussed above, the shutter10may be configured such that the north pole of the magnet24is disposed in the gap34. In an additional exemplary embodiment of the present disclosure, however, the magnet24could be inverted such that the south pole of the magnet24is disposed in the gap34and the north pole of the magnet24is spaced either above or below the gap34. In such an exemplary embodiment, however, because the operative faces32a,32bof the solenoid26may be controlled to have opposite polarities, only one pole of the magnet24may be disposed in the gap34between the operative faces32a,32bof the solenoid26so that each operative face32a,32b“sees” the same polarity of the magnet24. In addition, in each of the embodiments discussed above, the solenoid26may be disposed on a first surface of the drive ring18, and the shutter blades16may be disposed on a second, oppositely-facing, surface of the drive ring18. The permanent magnet24may be mounted to protrude from the first surface of the drive ring18.

FIG. 3illustrates an additional exemplary embodiment of the present disclosure. In this embodiment, two solenoids26,26′ are provided in a shutter100. The second solenoid26′ is substantially identical to the first solenoid26, described above, and the two solenoids26,26′ may be disposed proximate first40and second42oppositely-facing surfaces of the drive ring18, respectively. Also in this embodiment, the permanent magnet24may be disposed through the drive ring18, such that a first end of the magnet24is disposed in the gap34between operative faces32a,32bof the first solenoid26and a second end of the magnet24is disposed in the gap34′ between operative faces32a′,32b′ of the second solenoid26′. The shutter100illustrated inFIG. 3may function substantially similarly to the shutter10illustrated inFIGS. 1 and 2, and the presence of the second solenoid26′ may assist in providing additional force for the actuation of the permanent magnet24. As a result, the exemplary embodiment illustrated inFIG. 3may be utilized in applications in which the shutter component being actuated by the permanent magnet24requires a greater amount of force to move. Such embodiments may include those in which a large number of shutter blade16are used.

FIG. 4illustrates a shutter200according to yet another exemplary embodiment of the present disclosure. Where possible, like reference numbers have been used to describe the components of the shutter200. Although not shown inFIG. 4, it is understood that the shutter200may also include a cover mounted to the base plate12.

As shown inFIGS. 4 through 11, the shutter200can include a plurality of shutter blades16pivotally mounted and/or otherwise connected to a base plate12. The shutter200can also include a magnet50such as, for example, a permanent magnet that is movably and/or otherwise connected to at least one of the shutter blades16. The shutter200can also include a solenoid26defining a gap34between a first pole and a second pole. As will be described below, the solenoid26may be configured to controllably draw the magnet50into the gap34in a first state and to controllably repel the magnet50from the gap34in a second state. Such states may be defined by the respective polarities of poles defined by the solenoid26. The solenoid26may also be configured so as to extend along and/or otherwise lie in a plane62substantially parallel to the plurality of shutter blades16. The solenoid26may, thus, define a central axis60that is perpendicular to the plane62.

The plurality of shutter blades16may be made from, for example, hardened aluminum, cold-rolled steel, stainless steel, titanium, and/or any other metal or alloy commonly used in shutters for photographic, scientific, or calibration applications. The shutter200may include any desirable number of shutter blades16known in the art. For example, althoughFIGS. 4 through 11illustrate only two shutter blades16, it is understood that the shutter200can include at least one shutter blade16, or more than two shutter blades16depending upon the application in which the shutter200is being used. Accordingly, the shutter blades16can have any shape, size, and/or other configuration known in the art. The shutter blades16can be, for example half-moon shaped, teardrop shaped, substantially triangular, substantially square, substantially rectangular, and/or any other shape known in the art. The shutter blades16may preferably be as thin as possible so as to reduce a profile of the shutter200. The shutter blades16may be pivotally, rotatably, and/or otherwise movably connected to the base plate12in anyway known in the art. For example, the shutter200may include a pin52fixedly attached to base plate12, and each of the shutter blades16may be configured to rotate about the pin52between an open position (shown inFIG. 4) and a closed position (shown inFIG. 7). When in the open position, the shutter blades16may permit light to pass through the shutter opening14defined by the base plate12. Likewise, when in the closed position, the shutter blades16may occlude light from passing through the shutter opening14. It is understood that the shutter200may include additional pins52, and each of the shutter blades16may be pivotally connected to at least one pin52.

The base plate12of the shutter200may be substantially disc-shaped, substantially square, substantially rectangular, and/or any other shape known in the art. The base plate12may define one or more channels within which components of the shutter200may be disposed. For example, one or more channels of the base plate12may support, accept, and/or otherwise house the solenoid26and/or the magnet50. The base plate12may be made from any metals, plastics, alloys, polymers, and/or other materials known in the art, and at least a portion of the base plate12may be made from a substantially non-magnetic metal or alloy. As discussed above with respect to the shutter blades16, it may be desirable for the base plate12to be as thin as possible to as to minimize the overall dimensions of the shutter200.

As shown inFIGS. 4 through 11, the magnet50may be movably connected to each shutter blade16of the plurality of shutter blades and may be movable within, for example, a channel defined by the base plate12. As discussed above, the magnet50may be any type of magnet known in the art such as, for example, a permanent magnet having a north pole and a south pole. The magnet50may have any shape, size, and/or other configuration known in the art. For example, the magnet50may be sized and/or shaped to facilitate rapid movement of the shutter blades16. As shown in at leastFIGS. 5,6,8, and9, the magnet50may define at least one knob66movably disposed within each slot54of the shutter blades16. In an exemplary embodiment, the knob66may protrude from a top portion of the magnet50and the knob66may be substantially cylindrical in shape so as to reduce the friction created by movement of the knob66within the slots54. As shown inFIGS. 10 and 11, in another exemplary embodiment, the knob66may be omitted and the magnet50itself may be substantially cylindrical. In such an embodiment, the magnet50may define a portion movably disposed within each slot54, and the slots54may be sized and/or otherwise configured to move relative to the rounded portion of the magnet50disposed therein.

It is understood that the slots54may be shaped, sized, and/or otherwise configured to accept movement of any portion of the magnet50disposed therein. Accordingly, movement of a portion of the magnet50, such as the knob66, within the slots54, may assist in transitioning the shutter blades16between the open position (FIG. 4) and the closed position (FIG. 7).

As shown in at leastFIGS. 6,9, and11, the magnet50may include a flat surface defining a north pole N and another flat surface defining a south pole S. The flat surfaces defining the poles N, S of the magnet50may be disposed adjacent to the operative faces32a,32bof the solenoid26. The magnet50may also define a center line70passing through the midpoint and/or magnetic center of the north and south poles N, S. In an exemplary embodiment, the center line70may be substantially perpendicular to the flat surfaces of the magnet50defining the north pole N and the south pole S. In the embodiment shown inFIGS. 10 and 11, the slots54(not shown) may fit over the flat surfaces of the magnet50such that only the rounded portion of the magnet50contacts the shutter blades16to assist in the transition between the open and closed positions.

The magnet50may be configured to move in the direction of arrow56(FIGS. 4-6) to transition the shutter blades16into the open position, and the magnet50may be configured to move in the direction of arrow58(FIGS. 7-9) to transition the shutter blades16into the closed position. The shutter200may also include one or more stops64,65configured to limit and/or restrict the movement of the magnet50in the direction of arrow56and arrow58. The stops64,65may be fixedly disposed within the base plate12and may be any structure known in the art configured to limit and/or restrict the movement of a movable structure disposed proximate thereto. The stops64,65may be made from any dampening material known in the art such as, for example, rubber, plastics, and/or polymers. The stops64,65may be non-brittle and may be configured to tolerate repeated impacts with one or more moving parts such as, for example, the magnet50of the shutter200. In an exemplary embodiment, the stops64,65may comprise one or more dampers configured to limit and/or otherwise restrict the travel of the magnet50relative to the gap34. In such an exemplary embodiment, the stops64,65may soften the impact of the magnet50as it transitions the shutter blades16between the open position and the closed position. The stops64,65may have any shape, size, and/or other configuration known in the art configured to assist in dampening the impact of the magnet50. For example, the stops64,65may comprise one or more nylon set screws configured to dampen the magnet50upon impact therewith.

In an exemplary embodiment, the stops64,65may be positioned within the base plate12so as to prohibit the north pole N and south pole S of the magnet50from moving into a position aligned with, for example, magnetic poles defined by the first and second operative faces32a,32bof the solenoid26, respectively. In such an exemplary embodiment, the solenoid26and/or the core30may define a center line68passing through the magnetic center of the poles defined by the first and second operative faces32a,32b. The first and second operative faces32a,32bmay have opposite polarities and the polarities of these poles may be controlled by the driver38(FIGS. 1-3). Accordingly, in such an exemplary embodiment, the stop65may be positioned to prohibit the magnetic poles N, S of the magnet50from moving into alignment with the magnetic poles defined by the operative faces32a,32bof the solenoid26. In particular, as shown inFIGS. 6 and 11, the stop65may prohibit the center line70of the poles N, S of the magnet50from aligning with the center line68of the poles defined by the operative faces32a,32b, respectively. Thus, when the shutter blades16are in the open position, the permanent magnet50may be prohibited from fully entering the gap34and the magnetic center line70of the poles N, S of the magnet50may be prohibited from completely aligning with the magnet center line68of the poles defined by the operative faces32a,32bof the solenoid26.

In addition, when the shutter blades16are in the closed position, the center line70may be even further out of alignment with the center line68as shown inFIG. 9. In addition, the flat surface of the magnet50defining the south pole S may be a distance d1from the operative face32bof the solenoid26, and the flat surface defining the north pole N of the magnet50may be a distance d2from the operative face32a. As shown inFIG. 9, in an exemplary embodiment the distance d1may be substantially equivalent to the distance d2and the magnet50may remain substantially equidistant from the first and second operative faces32a,32bwhile the magnet50moves in the direction of arrows56,58.

The solenoid26may be substantially similar to the solenoid26discussed above with respect toFIGS. 1 through 3. In an exemplary embodiment, the solenoid26may have any shape, size, and/or other configuration known in the art. For example, the solenoid26may be substantially square, substantially rectangular, substantially C-shaped, and/or any other configuration capable of controllably delivering an electromagnetic charge. For example, as shown inFIGS. 4 through 11, the solenoid26may comprise a C-shaped core30defining a gap34between the first operative face32aand the second operative face32b. In addition, the first operative face32amay face the second operative face32b, and in such an embodiment, the electromagnetic flux lines of the solenoid26may travel substantially directly between the poles defined by the operative faces32a,32b.

As shown inFIGS. 1 through 3, the solenoid26may further comprise a coil of wire28wound around the core30and the wire28may be electrically connected to the driver38. For ease of illustration, the coil of wire28and the driver38have been omitted fromFIGS. 4 through 11. Although not illustrated inFIGS. 4 through 11, it is understood that the number of turns and/or the length of the wire28may define the electromagnetic strength of the poles defined by the operative faces32a,32bof the solenoid26, and the greater the number of turns (i.e., the greater the length) of the coil28, the more powerful the solenoid26.

With such a coil configuration, the solenoid26may be operable using a much lower voltage than conventional electromagnets. In an exemplary embodiment, the solenoid26may provide a relatively large magnetic flux between the poles defined by the operative faces32a,32bwith a relatively low voltage being supplied thereto. For example, the solenoid26may be operable utilizing less than 5 volts of electrical power and, in exemplary embodiments, the solenoid26may be operable utilizing less than 3 volts. Reducing and/or substantially minimizing the size of the gap34may assist in increasing the power of the solenoid26. Thus, the distances d2, d1between the poles N, S of the magnet50and the poles defined by the operative faces32a,32bof the solenoid26may be desirably as small as possible. In an exemplary embodiment, the distances d1, d2may be equal to, approximately, 0.125″ or less.

As discussed above, the magnet50may remain substantially equidistant from the first and second poles of the solenoid26as the magnet50is drawn into and repelled from the gap34. The polarity of each pole of the solenoid26may be controllably reversed by the driver38to controllably draw the magnet50into the gap34in a first magnetic state and controllably repel the magnet50from the gap34in a second magnetic state. As shown in at leastFIGS. 5,8, and10, the magnet50may be configured to travel along a substantially linear path, and the path of the magnet50may be substantially coplanar with the solenoid26. The linear path of the magnet50may also be substantially perpendicular to a line, such as, for example, the centerline68, connecting the poles defined by the operative faces32a,32bof the solenoid26.

The central axis60of the solenoid26may be substantially parallel to the central axis36of the shutter opening14and, in an exemplary embodiment, the central axis60may be co-linear with the central axis36. Thus, as shown inFIGS. 5,6,10, and11, the solenoid26may be configured to draw the magnet50into the gap34along the plane62in a direction perpendicular to the central axis60of the solenoid26. Likewise, as shown inFIGS. 8 and 9, the solenoid26may be configured to repel the magnet50from the gap34along the plane62and perpendicular to the central axis60.

In such an exemplary embodiment, the magnet50may travel along a linear path between the stops64,65, and this linear path may be substantially coplanar with the plane62. Although not explicitly illustrated inFIGS. 4 through 11, it is understood that this linear path may be substantially defined by a channel and/or other structures or components of the base plate12. For example, the stops64,65may define at least a portion of the path. It is understood that the path traveled by the magnet50may extend transverse to the gap34defined by the solenoid26. As will be described in greater detail below, the magnet50may be configured to move in the path in response to the polarities of the poles defined by the first and second operative faces32a,32b.

In an additional exemplary embodiment of the present disclosure, the shutter200may include one or more feedback sensors configured to assist in controlling the position of the magnet50. The sensors72,74(FIGS. 5,8, and10) may comprise any type of electromagnetic and/or position sensor known in the art. For example, the sensors72,74may comprise a Hall effect sensor and a portion of the Hall effect sensor may be mounted proximate the magnet50. Exemplary mounting locations may include positions above or below one or both of the stops64,65. Alternatively, the sensors72,74may comprise a current sensor configured to sense the current traveling through the coil28of the solenoid26. In the exemplary embodiments discussed above, the driver38may receive feedback signals produced by the one or more sensors72,74. The signals may be indicative of a change in current travelling through the solenoid26as a result of the position of the magnet50within the gap34. The driver38may then alter the current directed to the solenoid26to control the position of the magnet50within and/or otherwise relative to the gap34.

In still another embodiment, the sensors72,74may comprise a micromagnet mounted to one or more of the shutter blades16and a corresponding transponder mounted to a stationary component of the shutter200to detect the relative position of the micromagnet. In still a further embodiment, the sensors72,74may comprise a flag or other structure mounted to the magnet50and a corresponding sensor configured to detect the position of the flag. In such exemplary embodiments, the driver38may receive feedback from the one or more sensors72,74based on the change in position of the sensor components. In each of the embodiments discussed above, the feedback received from the sensors72,74may be utilized to detect and/or otherwise assist in controlling the position of the magnet50, thereby controlling the position of the shutter blades16.

FIGS. 12-18illustrate a shutter assembly300according to an additional exemplary embodiment of the present disclosure. Wherever possible, components of the shutter assembly300that are substantially the same as those described above with respect to, for example,FIGS. 4-11, will be described below using like reference numerals.

The shutter assembly300may include, for example, a plurality of shutter blades16pivotally mounted and/or otherwise connected to a base plate12. The shutter assembly300may also include a drive ring18that is movably connected to the shutter blades16and configured to rotate with respect to the base plate12, for example, about a central axis36(FIG. 17) of the shutter assembly300. The drive ring18may include a permanent magnet50connected thereto. In an exemplary embodiment, the permanent magnet50may be connected to a perimeter of the drive ring18. The shutter assembly300may also include a solenoid26defining a gap34between a first magnetic pole and a second magnetic pole as shown in, for example,FIG. 16. Such first and second magnetic poles may be disposed on a first face32aand a second face32bof the solenoid26, respectively. As will be described in greater detail below, the solenoid26may be configured to produce a variable and/or otherwise controllable magnetic field between the first and second magnetic poles and/or proximate the gap34. Accordingly, the solenoid26may be configured to control motion and/or movement of the drive ring18and the magnet50connected thereto. In particular, the solenoid26may be controlled to desirably position the magnet50relative to the gap34. The solenoid26may also be controlled to magnetically accelerate and/or magnetically decelerate movement of the magnet50, and/or the drive ring18, while transitioning the plurality of shutter blade16between an open position, illustrated inFIG. 13, and a closed position, illustrated inFIG. 16.

In an exemplary embodiment, the solenoid26may be disposed on a first side84of the base plate12. As discussed above with respect toFIGS. 4-11, the solenoid26may comprise a wire28wound about a core30. As shown in at least, for example,FIGS. 12,14, and18, the solenoid26may take the shape of the core30. Thus, in an exemplary embodiment, the solenoid26may be generally arcuate and may have an inner diameter larger than the diameter of the central opening14such that the solenoid26may be disposed substantially annularly around the central opening14and/or the central axis36(FIG. 17). The core30, and thus the solenoid26, may be, for example, substantially C-shaped and may terminate at the operative faces32a,32b.

The faces32a,32bmay form the first and second magnetic poles of the solenoid26and, in an exemplary embodiment, the poles of the solenoid26may be controlled to have opposite magnetic polarities. At least a portion of the permanent magnet50may be disposed within the gap34between the first and second faces32a,32b. As shown inFIG. 18, the wire wound about the solenoid core may form leads proximate the first and second faces32a,32b, and the leads may be connected to a solenoid driver38via wires92,94, respectively. When the driver38applies an electrical current to the solenoid26via the wires92,94, the faces32a,32bof the solenoid26may become oppositely polarized. In particular, when a first electrical current is applied to the solenoid26, the first operative face32amay take on a first polarity, i.e., a north or south polarity, and the second operative face32bmay take on an opposite polarity.

As described above with respect toFIGS. 4-11, the solenoid26may be controlled by the driver38to create a desirable magnetic field proximate the gap34and to thereby control movement of the permanent magnet50. Movement of the magnet50, and the corresponding movement of the drive ring18, may assist in transitioning the plurality of shutter blades16between the open and closed positions. It is understood that with the magnet50and drive ring18in a first position, as illustrated inFIG. 12, wherein the magnet50is closer to the first face32a, the shutter blades16may be in the open position shown inFIG. 13. Conversely, when the magnet50and the drive ring18are in a second position, defined by the magnet50being disposed closer to the second face32b, the shutter blade16may be in the closed position as shown inFIG. 15. The solenoid26may be controlled to rotatably move the drive ring18about the central axis36of the shutter assembly300to obtain the first and second positions discussed above, as well as other intermediate positions. For example, the polarity of the faces32a,32bmay be desirably reversed as the plurality of shutter blades16is transitioned between the open and closed positions. Movement of the drive ring18in response to a variable electrical current provided to the solenoid26and/or a variable electrical field created by the solenoid26will be described in greater detail below.

The drive ring18may be rotatable relative to the base plate12in the direction of arrow44(FIG. 12) and arrow46(FIG. 14). In an exemplary embodiment, the drive ring18may be substantially annular and may be configured to rotate about the central axis36. The drive ring18may be disposed on the first side84of the base plate12and, in an exemplary embodiment, the drive ring18may be disposed substantially coplanar with the solenoid26. In addition, the drive ring18may be disposed substantially concentric with the solenoid26such that both the solenoid26and the drive ring18are centered about a center point78of the central opening14. In exemplary embodiment, the central axis36may extend substantially perpendicular to the center point78, and the central opening14may define a shutter opening of the shutter assembly300. For example, the plurality of shutter blades16may expose the shutter opening while in the open position, thereby allowing light to pass through the central opening14. Alternatively, in the closed position, the plurality of shutter blades may substantially occlude the shutter opening, thereby prohibiting light from passing through the central opening14.

In an exemplary embodiment, the drive ring18may fit within a groove, slot, channel, and/or other portion of the base plate12to assist in guiding motion of the drive ring18. In addition, the base plate12and/or other components of the shutter assembly300may act as a stop configured to limit, for example, rotational motion of the drive ring18. In an exemplary embodiment, the base plate12may define stops64,65configured to limit the extent to which the drive ring18may rotate about the central axis36. In an exemplary embodiment, the stops64,65may act on a portion of the drive ring18such as, for example, a notch or a cutout defined by a portion of the drive ring18. Alternatively, the drive ring18may include one or more posts, extensions, and/or other structures (not shown) configured to interact with the stops64,65, thereby limiting the rotational motion of the drive ring18. In an additional exemplary embodiment, at least one of the stops64,65of the shutter assembly300may comprise a damper. Such dampers may include, for example, relatively soft movement impediments, and such impediments may be comprised of plastics, rubber, and/or other known dampening materials. Alternatively, as will be described below, the solenoid26may be configured to magnetically dampen motion of the drive ring18and, in such an exemplary embodiment, the stops64,65may be omitted.

The permanent magnet50may be disposed on the drive ring18and, in an exemplary embodiment, the magnet50may be connected to a perimeter of the drive ring18. At least a portion of the magnet50may be disposed within the gap34formed between the first and second faces32a,32bof the solenoid26. As shown inFIG. 16, a first pole of the permanent magnet50may be disposed within the gap34between the first and second faces32a,32bof the solenoid26, and a second pole of the magnet50may be disposed away from the gap34. For example, the north pole of the magnet50may be disposed within the gap34while the south pole of the magnet50may be disposed away from the gap34, and it is understood that this configuration may be reversed if desired. However, the configuration illustrated inFIG. 16will be described for the remainder of this disclosure for ease of description.

As shown inFIG. 16, when a first current is applied to the solenoid26, a south pole may be created at the first face32a, and a north pole may be created at the second face32b. Because the north pole of the permanent magnet50is disposed between the operative faces32a,32bof the solenoid26, the magnet50will be attracted by the first operative face32aand repelled by the second operative face32b. Accordingly, in such an embodiment, the drive ring18will be moved in the direction of arrow44such that the permanent magnet50may be disposed proximate the first operative face32a. Movement of the magnet50drives the drive ring18about the central axis36to open the shutter blades16, as illustrated inFIG. 13. Conversely, when an opposite current is applied to the solenoid26, the polarity of the faces32a,32bmay be reversed. In particular, in such an embodiment, a north pole may be created at the first face32aand a south pole may be created at the second face32b, thereby forcing the magnet to move in the direction of arrow46(FIG. 14). Such movement will rotate the drive ring18about the central axis36to close the shutter blades16as illustrated inFIG. 15. As the permanent magnet50is disposed on the drive ring18, the permanent magnet50may travel in an arcuate path between the first face32aand the second face32b. Thus, the permanent magnet50may travel in an arcuate path between the first and second magnetic poles of the solenoid26in response to variations in an electrical current supplied to the solenoid26and/or variations in an electrical field created by the solenoid26proximate the gap34.

The drive ring18may be coupled to the plurality of shutter blades16by any structure or structures known in the art. For example, as illustrated inFIG. 13, the drive ring18may include one or more knobs76and/or other structures configured to induce motion of the shutter blade16. In an exemplary embodiment, the one or more knobs76of the drive ring18may be movably disposed in a slot or groove defined by each shutter blade16. Each of the shutter blades16may also be held rotatably in place by one or more pins52connected to, for example, the base plate12. In such an exemplary embodiment, the shutter blades16may be configured to rotate about the pin52in response to motion of the knob76connected to the drive ring18. Motion of the one or more knobs76of the drive ring18may cause the plurality of shutter blades16to transition between the open and closed positions. Such an exemplary configuration may be described as a cam follower relationship and, it is understood, that any other like configuration may be utilized in the shutter assembly300to impart motion to the plurality of shutter blades16.

The shutter blades16may be mechanically similar to the shutter blades16described above with regard toFIGS. 4-11. As shown inFIG. 13, the plurality of shutter blades16may be disposed on a second side86of the base plate12. In such an exemplary embodiment, the drive ring18and/or the solenoid26may be disposed on the first side84of the base plate12such that the plurality of shutter blades16is movably disposed on an opposite side of the base plate12therefrom. Thus, the base plate12may be configured to separate the plurality of shutter blades16from at least one of the drive ring18and the solenoid26. In addition, althoughFIGS. 12-17illustrate an exemplary embodiment of the shutter assembly300having only two shutter blades16, it is understood that any useful number of shutter blades16may be incorporated into the shutter assemblies described herein. For example, as shown inFIG. 19, in an exemplary embodiment of the present disclosure a shutter assembly400may include three shutter blades16. As described above, the shutter blades16of the present disclosure can have any shape, size, and/or other configuration known in the art. The shutter blades16can be, for example, half-moon shaped, tear-dropped shaped, substantially triangular, substantially square, substantially rectangular, and/or any other shape known in the art depending upon the application in which the shutter assembly is being used.

In each of the exemplary embodiments described herein, an electrical signal applied to the one or more solenoids may be increased, reduced, and/or otherwise varied. For example, an electrical current provided to the one or more solenoids may be reduced, increased, varied, modified, and/or otherwise modulated to control the movement of the one or more magnets relative to, for example, the solenoid coils, and/or the one or more dampers and/or stops. As described above, the polarity of each pole of the solenoid26may be controlled so as to control the motion of the magnet50and, thus, the drive ring18within the shutter assembly300.

In an exemplary embodiment, the electrical current provided to the solenoid26may be increased, reduced, varied, modified, and/or otherwise modulated to control the movement of the magnet50relative to, for example, the first face32aand the second face32b. Such variations in the current may, for example, cause a related and corresponding variation in the electrical field created by the solenoid26between the first and second faces32a,32b. It is also understood that the current provided to the solenoid26and, thus, the magnetic field created by the solenoid26may be varied while transitioning the plurality of shutter blades16between the open and closed positions. It is also understood that the electrical current provided to the solenoid26and/or the magnetic field created between the first and second magnetic poles of the solenoid26may be altered, varied, and/or otherwise modified in response to a sensed position of the permanent magnet50relative to, for example, the gap34, at least one of the faces32a,32b, and/or other stationary components of the shutter assembly300.

In an exemplary embodiment, varying the electrical current applied to the solenoid26may include reversing a polarity of the current supplied thereto. For example, as shown inFIG. 18, the polarity of each pole of the solenoid26may be controllably varied by the driver38to controllably draw the permanent magnet50toward either face32a,32bof the solenoid26. In an exemplary embodiment, the polarity of the current applied to the solenoid26may result in a south pole being formed at the first face32aand a north pole being formed at the second face32b, as shown inFIG. 16. Reversing the polarity of the electrical current supplied to the solenoid26may, in turn, form a north pole at the first face32aand a south pole at the second face32b, thereby drawing the magnet50toward the second face32band repelling the magnet50from the first face32a. In addition, the polarity of the electrical current may be alternated and/or otherwise repeatedly reversed during the transition of the shutter blades between the open and closed positions. Such a variation in the current may cause a corresponding variation in the magnetic field created between the first and second magnetic poles of the solenoid26, and may cause the magnet50to accelerate and/or decelerate as it travels between the first and second magnetic poles. For example, the polarity of the electrical current may be reversed at least once and/or repeatedly during the transitioning to magnetically dampen the movement of the magnet50. Such variations in the electrical current and such corresponding variations in the magnetic field may alternately attract and repel the permanent magnet50as the permanent magnet approaches one of the first and second magnetic poles of the solenoid26.

In addition, the current supplied to the solenoid26and/or the magnetic field created between the first and second magnetic poles of the solenoid26may be varied by, for example, applying a current pulse to the solenoid26. In an exemplary embodiment, at least one pulse may be provided to the solenoid26and in additional exemplary embodiments, a plurality of pulses may be provided. In such an exemplary embodiment, the pulses applied to the solenoid26may be of varying widths and/or may be applied to the solenoid26for varying lengths of time. For example, first and second current pulses may be applied to the solenoid26, and the first current pulse may be longer, shorter, or equal to the second pulse. As described above with regard toFIG. 7, it is understood that applying such pulses of electrical current to the solenoid26may controllably accelerate or controllably decelerate the magnet50and the drive ring18during movement. In particular, such pulses may be provided to controllably accelerate or decelerate the magnet50while transitioning the plurality of shutter blades16between open and closed positions. It is understood that such accelerated or decelerated movement of the magnet50and drive ring18will result in a corresponding accelerated or decelerated movement of the plurality of shutter blades16connected thereto. Accordingly, the amount and/or area of the central opening14exposed by the movement of the shutter blades16between the open and closed positions can be controlled through the proper timing, duration, and magnitude of such pulses.

In still another exemplary embodiment of the present disclosure, the shutter assembly300may include at least one sensor configured to detect a position of the permanent magnet50and/or a position of the drive ring18. It is understood that such positions may be radial positions with respect to, for example, the gap34, the faces32a,32b, and/or the center point78. It is also understood that the one or more sensors may be part of a sensor assembly disposed within and/or proximate to the shutter assembly300.

The one or more sensors may comprise any type of electromagnetic and/or position sensors known in the art. For example, as shown inFIG. 18, the sensor assembly may comprise a position sensor80that is mounted in a stationary location with respect to the drive ring18. Such a position sensor may include a Hall effect sensor, an infrared sensor, and/or other known sensors. The sensor assembly may also include a magnet82disposed on the drive ring18proximate the position sensor80. The position sensor80may detect the radial position of the magnet82disposed on the drive ring and may send a feedback signal to, for example, a driver38. From such feedback signals, the driver38may determine the positions of, for example, the drive ring18, the magnet50, and/or the plurality of shutter blades16. In response to such calculated positions, the driver38may, for example, send a desired electrical current to the solenoid26via the control lines92,94. In particular, the driver38may alter, modify, vary, and/or otherwise adjust the current provided to the solenoid26in response to the sensed and/or calculated position of the shutter blades16. Varying the current in this way may cause a corresponding variation in the magnetic field created by the solenoid26.

Accordingly, in the exemplary embodiment illustrated inFIG. 18, the shutter assembly300may be servo driven and may incorporate one or more feedback control loops as part of the preprogrammed logic used to control motion and/or position of the shutter blades16. In such an exemplary embodiment, the driver38may be preprogrammed with a desired set point corresponding to, for example, a position of the shutter blades16at the open or closed position. The position sensor80may then detect the position of the magnet82, and the driver38may convert this position information to an acceptable format for comparison with the preprogrammed set point. The driver38may compare the converted position value with the preprogrammed set point, and if the preprogrammed set point is greater than the sensed position value, the driver38may direct an electrical current to the solenoid26to rotate the magnet50and drive ring18in the direction of arrow44(FIG. 12). Alternatively, if the preprogrammed set point is less than the sensed position point, the driver38may send an electrical current to the solenoid26rotating the drive ring18and magnet50in the direction of arrow46(FIG. 14). Such feedback control may continue until the shutter blades16are desirably opened or desirably closed.

In an additional exemplary embodiment, the sensor80may be positioned proximate the magnet50, and in such an exemplary embodiment, the magnet82may be omitted. In still another exemplary embodiment, the sensor80may comprise a current sensor configured to sense at least one property of an electrical current passing through the solenoid26. Such a property may include, for example, a voltage of the electrical current and/or a flow of electrical charge (Amperes).

In still another embodiment of the present disclosure, the sensor80may comprise a micromagnet mounted to one or more of the shutter blades16, and a corresponding transponder mounted to a stationary component of the shutter assembly300to detect the relative position of the micromagnet. In still a further embodiment, the sensor assembly may comprise a flag or other structure mounted to, for example, the drive ring18, the magnet50, and/or one or more of the shutter blades16. In such an exemplary embodiment, the sensor assembly may further include a corresponding sensor80configured to detect the position of the flag. In each of the embodiments of the sensor assembly discussed above, the driver38may receive feedback signals produced by the one or more components of the sensor assembly based on, for example, the change in position of the sensor assembly components and/or a change in the electrical current provided to the solenoid26. The feedback received from the sensor80may be utilized to detect and/or otherwise assist in controlling the position of the magnet50, thereby controlling the position of the shutter blades16in a closed loop manner. The driver38may alter the current directed to the solenoid26to control the position of the magnet50within and/or otherwise relative to the gap34.

In an exemplary embodiment of the present disclosure, the shutter assemblies200,300,400may be used to open and close shutter blades16in one or more photographic device applications. For example, the shutter assemblies200,300,400may be utilized to expose photographic film to light for a desired period of time, thereby forming an image on the film. In such an application, the shutter assemblies200,300,400may be components utilized in a camera or other like photographic device.

As explained with respect toFIGS. 1-11, the driver38may direct an electrical current to the solenoid26via the wire28. The current directed to the solenoid26may form, for example, a north pole at the operative face32aand a south pole at the operative face32b, as shown inFIG. 9. In such an exemplary embodiment, the north pole N of the magnet50may be repelled by the north pole of the operative face32a, and the south pole S of the magnet50may be repelled by the south pole defined by the operative face32b. Thus, the magnet50may be at least partially repelled from the gap34and may be forced adjacent to the stop64. Repelling the magnet50at least partially from the gap34may cause the plurality of shutter blades16to achieve the closed position illustrated inFIG. 7. In particular, controlling the operative faces32a,32bto have the polarities shown inFIG. 9may repel the magnet50in the direction of arrow58such that the knob66of the magnet50may travel in the slots54defined by the shutter blades16, in the direction of arrow58, thereby closing the shutter blades16. Each of the plurality of shutter blades16is movably connected to the pin52and, thus, movement of the magnet50in the direction of arrow58within the slot54may move the plurality of shutter blades16about the pin52to achieve the closed position illustrated inFIG. 7.

To transition the shutter200to the open position illustrated inFIG. 4, and thereby expose and/or otherwise open the shutter opening14, the driver38may be controlled to reverse the polarity of the poles of the solenoid26. In particular, the driver38may direct a current to the solenoid26defining a south pole at the operative face32aand a north pole at the operative face32b. The south pole defined by the operative face32amay attract the north pole N of the magnet50and the north pole defined by the operative face32bmay attract the south pole S of the magnet50. Accordingly, the magnet50may travel in the direction of arrow56and may be drawn into the gap34. Movement of the magnet50into the gap34may be restricted by the stop65. In particular, the stop65may prohibit the poles N, S of the magnet50from moving into a position aligned with the poles defined by the first and second operative faces32a,32bof the solenoid26. As shown in at leastFIGS. 6 and 11, the stop65may be positioned to prohibit the center line70of the poles N, S of the magnet50from aligning with the center line68of the solenoid26.

Drawing the magnet50at least partially into the gap34defined by the first and second poles of the solenoid26causes the plurality of shutter blades16movably connected to the magnet50to achieve the open position illustrated inFIG. 4. In particular, the knob66of the magnet50may travel in the direction of arrow56within the slot54of the shutter blades16so as to substantially expose and/or otherwise open the shutter opening14. Each of the shutter blades16may also pivot and/or otherwise move about the pin52when transitioning between the open and closed positions described herein.

As described above, in transitioning the shutter200between the open and closed positions, the magnet50may move in a path coplanar with the solenoid26and substantially perpendicular to the central axis60of the solenoid26in response to the polarities of the first and second poles of the solenoid26. Because the poles N, S of the magnet50are prohibited from moving into a position aligned with the first and second poles of the solenoid26when the magnet50is drawn into the gap34, simply reversing the polarity of the poles defined by the operative faces32a,32bof the solenoid26may provide ample electromagnetic force to effectively repel the magnet50from the gap34. In an alternative embodiment in which the poles N, S of the magnet50were permitted to substantially align with the poles defined by the operative faces32a,32b, simply reversing the polarity of the poles defined by the operative faces32a,32bmay not cause the magnet50to travel in the direction of either arrow56or arrow58. In such an exemplary embodiment, an additional mechanism may be required to induce movement of the magnet50and/or the shutter blades16.

Moreover, as described above with respect toFIGS. 12-19, the electrical current applied to the solenoid26and the magnetic field created between the first and second magnetic poles of the solenoid26may be varied while the plurality of shutter blades16is transitioned between the open and closed positions. Such variations may be controlled by the user as desired in order to produce a variable shutter opening and/or shutter closing pattern as necessary for different shutter assembly applications. For example, the shutter blades16may be controlled to accelerate and/or decelerate while transitioning between the open and closed positions. Such accelerations may be, for example, linear, stepwise, and/or exponential. Alternatively, the plurality of shutter blades16may be controlled during the transitioning to have any other velocity, acceleration, and/or movement pattern useful in shutter applications. It is also understood that the movement of the shutter blades16may cause a corresponding change in the area of the central opening14exposed by the shutter assembly300. Thus, the area of the central opening14that is exposed by the shutter assembly300may be varied, for example, in a linear, stepwise, exponential, and/or other manner as dictated by the controlled movement of the plurality of shutter blades16.

As is also discussed above, the acceleration, deceleration, and/or other movement of the shutter blades16may be controlled using a closed loop feedback control strategy. For example, the shutter assembly may be servo-driven to assist in accelerating, decelerating, and/or otherwise modifying the movement of the plurality of shutter blades16while transitioning the plurality of shutter blades16between the open and closed positions. It is understood that the shutter assemblies200,300,400described herein may comprise any combination of sensors, sensor components, and/or other devices to facilitate the closed loop control of the position and/or movement of, for example, the drive ring18, the permanent magnet50, and/or the plurality of shutter blades16.

Other embodiments of the disclosed shutter will be apparent to those skilled in the art from consideration of this specification. It is intended that this specification and examples be considered as exemplary only, with the true scope of the invention being indicated by the following claims.