Base slat retention and motor triggering for rolling protective shutters

The present invention is directed to a rolling protective shutter having an improved stopping mechanism that prevents the shutter from completely rolling up onto the shutter support member, and that is hidden within the shutter housing or the side tracks. The stopping mechanism may include a limit switch operatively connected to a drive motor to detect a disposition of the base slat of the shutter curtain proximate the shutter housing. The limit switch may actuate to turn off the drive motor at an appropriate position to retain the base slat within the side tracks and to prevent damage to the shutter housing due to engagement by the base slat.

BACKGROUND

The present invention is directed to a rolling protective shutter assembly which has a shutter curtain for covering a window or door opening that may be rolled up into a shutter housing when not in use, and in particular to a motor-driven shutter assembly configured to shut off the motor when the base slat is detected to be proximate the shutter housing, with the base slat being retained by the side tracks of the assembly to facilitate proper deployment of the shutter curtain when the motor operates to unroll the shutter curtain.

Rolling protective shutters are conventional and are used to provide protection against extreme weather conditions and to deter theft, for example. One such rolling protective shutter is disclosed in U.S. Pat. No. 4,345,635 to Solomon. As shown inFIGS. 1 and 2of that patent, the Solomon shutter is composed of a plurality of elongate slats, each of which has a pair of circular ribs attached to its sides. The slats are interconnected by a plurality of elongate hinges, each of which has a pair of circular apertures in which the circular ribs of the slats are disposed. When the Solomon shutter is unrolled to its protective position, each of the slats in the shutter is disposed vertically with the ends of the slats disposed with guide channels or side tracks on either side of the opening. When not in use, the Solomon shutter may be rolled up into a housing disposed at the upper end of the protective shutter.

Another type of rolling protective shutter is disclosed in U.S. Pat. No. 5,365,990 to Ueda. As shown in FIGS. 2 and 3 of that patent, the Ueda shutter is composed of a plurality of slats, each of which has an upper rearward hook extending longitudinally along the upper edge of the slat and a lower U-shaped recess extending longitudinally along the lower edge of the slat. The recess has a forward horizontal projection on a rear edge and extending longitudinally so that when the lower slat moves down under gravity, the hook of the lower slat bears on the horizontal projection of the upper slat. The Ueda shutter may be rolled up and unrolled in a similar manner as the Solomon shutter.

In rolling shutter systems such as the Solomon and Ueda shutters, a portion of the shutter must remain within the side tracks to prevent the shutter from completely rolling up onto the take-up roll within the shutter housing. In some applications, the base slat has a handle extending outwardly from the shutter. One way to stop the bottom of the shutter from entering the housing is to size the opening in the housing through which the shutter passes narrow enough so that the handle hits the housing. The bottom of the shutter will stop short of entering the housing, but in many installations the housing is fabricated from sheet metal that is easily bent if the shutter is rolled up too rapidly.

In another alternative for stopping the bottom of the shutter, metal braces are attached to the side tracks and extend inwardly into the opening so that they engage the handle as the shutter is rolled up. Although the braces are stronger than the sheet metal housing, the handle and the braces can be damaged from repeated metal-on-metal impacts. Both the handle and the braces can be bent, gouged or broken, thereby increasing the possibility that the entire shutter will roll up into the housing and causing deterioration of the appearance of the shutter system. Additionally, the shutter may make a loud bang when the metal handle impacts the metal braces.

One solution for manually operated shutters is provided in U.S. Pat. No. 6,095,224 to Miller (hereinafter “the Miller '224 patent”). In the Miller '224 patent, portions of the side tracks of the assembly extend upwardly into the shutter housing and include spring biased stop members. Locking members extend outwardly from either end of the base slat and beyond the width of the shutter curtain such that the locking members are engaged by the stop members as they approach or enter the shutter housing. Configured in this way, the stopping mechanism is not visible and, consequently, does not diminish the aesthetic qualities of the shutter assembly, and reduces the noise created when the shutter curtain reaches its limiting position.

While effective with manual shutters, such mechanical mechanisms generally are not applicable in motor-driven shutter assemblies due to the risk of damaging the motor when a load is applied to the shutter curtain by the stop mechanism. In currently known motor-driven shutter assemblies, the base slat is required to stay in the side tracks and cannot fully retract into the housing. In many cases, the base slat remains in the side tracks below the bottom of the shutter housing by 3″ or more, thereby reducing the size of the opening. The side tracks do not extend upwardly into the shutter housing in a manner that would retain the base slat so that the remaining slats of the shutter curtain are free to roll up onto shutter support member. The base slat must remain in the side tracks in order to lead the slats back into the side tracks when the shutter curtain is unrolled, with gravity pulling the shutter into the tracks as the shutter curtain is dispensed from the shutter support member. Additional weights are sometimes required to guarantee that the shutter curtain will be dispensed correctly despite friction and other forces caused by the engagement of the shutter curtain by the components of the shutter assembly. If the base is retracted completely into the shutter housing, it may not find its way back into the side tracks.

In some implementations, the drive motors are provided with limit switches to attempt to cut off the motor when the shutter curtain is rolled up to a desired position. However, the limit switch typically operates based on the angular displacement of the shutter support member, and not the actual position of the shutter curtain. The position of the base slat can vary based on the tightness with which the shutter curtain is wrapped around the shutter support member. Additionally, an arrangement such as that shown in the Miller patent may be used with a motor driven shutter assembly to ensure that the base slat cannot be pushed up into the housing and out of the side tracks, and thereby causing a failure of the shutter assembly. If the shutter curtain equipped with the stopping mechanism rolls up slightly incorrectly, the limit switch on the motor may not be reached, thereby causing the shutter curtain and motor to be put under stress that can cause a failure of the curtain or the motor.

In other implementations, the drive motors are designed to sense when the shutter curtain is subjected to a load, and to shut off in response. The motors are specially made and adjusted to sense the correct torque at the stop position, and to not stop under the weight load of the shutter curtain when the curtain is drawing up. The motor also should not stop due to frictional forces that invariably will be present as the shutter curtain moves within the side tracks. These configurations still require the base slat to be at least partially disposed in the side tracks to function as a leader for the shutter curtain, and weight may need to be put in the base slat to ensure that the base slat moves downward in the side tracks to properly deploy the shutter curtain, and thereby affecting the adjustment of the drive motor. As can be seen, these solutions for motor driven shutter assemblies present performance risks relating to the proper deployment of the shutter curtain and potential damage to the shutter curtain and/or motor. Therefore, a need exists for an improved mechanism for stopping the motor when a particular part of the shutter curtain, such as the base slat, reaches the upper limit, and for allowing the base slat to be recessed within the shutter housing without compromising the ability of the shutter curtain to be unrolled back into the shutter tracks.

SUMMARY OF THE INVENTION

The present invention is directed to a rolling protective shutter having improved shutter tracks. The improved shutter tracks according to the present invention include an improved stopping mechanism that prevents the shutter from completely rolling up onto the shutter support member and is hidden within the shutter tracks and/or the housing.

According to one aspect of the present invention, a rolling shutter assembly includes rolling shutter assembly for covering an opening of a structure. The rolling shutter assembly may include a shutter housing mounted at the top of the opening, a shutter support member mounted within the shutter housing, and a shutter curtain connected to the shutter support member at a top edge of the shutter curtain. The shutter curtain may have a base slat connected to a bottom edge of the shutter curtain, wherein the shutter curtain is rolled up onto the shutter support member when the shutter support member rotates in a first direction and is unrolled from the shutter support member when the shutter support member rotates in a second direction. The rolling shutter assembly may further include a pair of side tracks mounted on opposite sides of the opening and receiving corresponding ends of the shutter curtain when the shutter curtain is unrolled, a drive motor coupled to the shutter support member to rotate the shutter support member in both the first direction and the second direction, and a limit switch operatively connected to the drive motor and disposed within the shutter housing. The limit switch may have a normal position allowing the drive motor to be actuated to rotate in the first direction and an actuated position preventing the drive motor from being actuated to rotate in the first direction, wherein the limit switch detects a disposition of at least a portion of the base slat within the shutter housing and actuates to turn off the drive motor when the base slat is raised to a predetermined position within the shutter housing.

According to another aspect of the present invention, a rolling shutter assembly for covering an opening of a structure may include a shutter housing mounted at the top of the opening and having an end cap with a motor housing, a shutter support member mounted within the shutter housing, and a shutter curtain connected to the shutter support member at a top edge of the shutter curtain. The shutter curtain may have a base slat connected to a bottom edge of the shutter curtain and having a guide arm extending outwardly from either side of the base slat, wherein the shutter curtain is rolled up onto the shutter support member when the shutter support member rotates in a first direction and is unrolled from the shutter support member when the shutter support member rotates in a second direction. The rolling shutter assembly may further include a pair of side tracks mounted on opposite sides of the opening, a drive motor disposed within the motor housing and coupled to the shutter support member to rotate the shutter support member in both the first direction and the second direction, a limit switch operatively connected to the drive motor and disposed within the motor housing, and a trigger mechanism operatively coupled to the limit switch and having a portion extending downwardly through an opening in a bottom surface of the shutter housing. Each side track may have a first channel receiving a corresponding end of the shutter curtain when the shutter curtain is unrolled and a second channel receiving a corresponding guide arm of the base slat, wherein the second channel extends upwardly into the shutter housing. The limit switch may be normally closed to allow the drive motor to be actuated to rotate in the first direction and being open when actuated to prevent the drive motor from being actuated to rotate in the first direction, and the base slat may engage the trigger mechanism to actuate the limit switch to open the limit switch and turn off the drive motor when the base slat is raised to a predetermined position within the shutter housing.

The features and advantages of the invention will be apparent to those of ordinary skill in the art in view of the detailed description of the preferred embodiments, which is made with reference to the drawings, a brief description of which is provided below.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

One type of a rolling shutter assembly10that may implement the present invention is shown inFIGS. 1-3. Referring toFIG. 1, the shutter assembly10has a shutter housing which includes a top wall12, a pair of side walls or end caps14, a front wall16, a rear wall18and a bottom wall19. In many implementations, the top wall12, rear wall18and an upper portion of the front wall16are formed as a first housing component, and the remainder of the front wall16and the bottom wall19are formed as a second housing component to facilitate installation of the shutter assembly10. A shutter support member20is mounted for rotation within the shutter housing. The support member20includes a generally cylindrical central shaft22and a plurality of mounting members24fixed to the shaft22.

The upper end of a rolling shutter curtain30is coupled to one or more of the mounting members24. The shutter curtain30is composed of a plurality of individual, elongate slats32. One example of a configuration of slats32is illustrated inFIG. 2. The slats32, each of which may have a curved cross-section to facilitate wrapping around the shutter support member20, and may be composed of steel, aluminum, or other appropriate material, are interconnected by a plurality of hinges34, each of which joins together a pair of adjacent slats32. Each of the slats32includes an upward projection35extending longitudinally along the upper edge of the slat32and having a rearwardly and downwardly extending hook36at the top. Each of the slats32further includes a downward facing generally U-shaped recess37extending longitudinally along the lower edge of the slat32and having a forward horizontal projection38formed on one edge of the recess37and extending partially across the open end of the recess37. The hook36of a lower slat32and the recess37and projection38of an upper slat32interlock to form each hinge34. The recess37may further be formed with a semi-circular portion39forming an integral screw boss for engaging a retention member that will in turn engage the corresponding side track of the shutter assembly10to retain the shutter curtain30within the side tracks. This shutter slat configuration is illustrated and described more fully in U.S. Pat. No. 7,357,171 (hereinafter “the Miller '171 patent”), which is expressly incorporated by reference herein for all purposes. Another example of a shutter assembly with end retention is shown in the Miller '224 patent which is expressly incorporated by reference herein for all purposes. Other configurations of slats32and interconnecting hinges34, such as the configuration of the Solomon shutters, are well known in the art and are contemplated by the inventor as having use with the present invention.

Referring back toFIG. 1, the ends of the slats32are disposed within a pair of shutter side tracks40. The shutter assembly10may include a drive motor housing42at one of the end caps14containing a reversible drive motor, such as a tubular operator (not shown), connected to the rotatable shaft22to rotate the shaft22in either direction to raise and lower the shutter curtain30. The motor housing42may also include a gear assembly (not shown) connected to the shaft22with a removable hand crank for manually raising and lowering the shutter curtain30in the event of a failure of the drive motor, such as during a power outage. When mounted to protect a window or other opening, the side tracks40of the shutter assembly10are positioned on either side of the opening and the shutter housing is positioned over the top of the opening. Alternatively, in some applications, the side tracks40and shutter housing are positioned within the opening. When the shutter curtain30is not in use, it is rolled up on the shutter support member20via the drive motor or, if necessary, the hand crank so that it is at least partially enclosed by the shutter housing. The hand crank may be connected at the lower front portion of the end cap14in which the gear assembly is disposed or, depending on the particular installation, may extend from a rear portion of the shutter assembly10through the structure surrounding the opening so that the shutter curtain30can be unrolled from inside the building. Using the drive motor or the hand crank, the shutter curtain30is rolled up into the shutter housing until a base slat46and its base plate48are disposed at the shutter housing.

The structure of one example of previously known side tracks40is illustrated inFIG. 3, which is a horizontal cross-section of one of the side tracks40. Each side track40has a pair of side walls56,58, and an end wall60. The side track40further includes a first pair of fins62,64that extend inwardly from the side walls56,58, respectively, and define a first gap66that is wide enough to receive retention members (not shown) and engage the retention members to retain the shutter curtain30in a manner described more fully in the Miller '224 patent and in U.S. Pat. No. 6,095,225 (hereinafter “the Miller '225 patent”) which is expressly incorporated by reference herein for all purposes. A third fin68and semi-circular wall70define a second gap72that is wide enough to receive an engagement member such as an arm extending outwardly from the base slat46of the shutter curtain30as will be described more fully below. A second pair of fins74,76extends inwardly from the side wall56between the end wall60and semi-circular wall70and toward the other side wall58.

Configured in this way, the side tracks40provide multiple channels. The fins62,64and portions of the side walls56,58define a first channel adapted to receive the slats32,46when the shutter curtain30is unrolled. The fins62,64,68and a portion of the semi-circular wall70define a second channel adapted to receive the retention members as illustrated and described in the Miller '224 and '225 patents. The fin68and the remainder of the semi-circular wall70define a third channel adapted to receive the engagement member or arm of the base slat46and an adjustable throw member78as discussed more thoroughly below. Finally, the end wall60, portions of the side walls56,58, and the semi-circular wall70define a fourth channel that receives a nipple80extending downwardly from one of the end caps14when the end cap14is attached to the side track40, with the fins74,76engaging the nipple80to prevent movement within the fourth channel. The fins68, the semi-circular wall70, and portions of the side walls56,58extend upwardly partially into the shutter housing as will be discussed more fully below.

A retention and triggering mechanism according to the present disclosure may utilize engagement members or arms extending from the base slat46to engage an upwardly extending portion of the third channel in the shutter housing and to engage the adjustable throw member78disposed within one of the side tracks to actuate a limit switch within the shutter housing.FIG. 4is a side view of the upper portion of the shutter assembly10with the end cap14and shutter support member20removed for clarity. The lower portion of the side track40is shown in cross-section through line4L-4L ofFIG. 3to show the features of the base slat46, and the upper portion of the side track40within the shutter housing is shown in cross-section through line4U-4U ofFIG. 3to show the retaining portion of the side track40and the adjustable throw member78. The base slat46may have a generally rectangular cross-section for strength and to prevent the base slat46from twisting within the side track40. The base slat46includes a upward projection35and hook36similar to those of the slats32extending longitudinally along the upper edge of the base slat46so that the hook36may interlock with the recess37of the bottommost slat32of the shutter curtain30.

The base slat46may further include base plate48disposed at a bottom edge of the base slat46. The base plate48extends outwardly from the front of the base slat46by a distance that will allow the base plate48to cover the opening between the base slat46and the edge of the bottom side19of the shutter housing when the shutter curtain30is rolled up. The base plate48also has a width dimensioned to essentially span the distance between the inside edges of the side tracks40. As illustrated, the base plate48may be attached to the base slat46via bolts, rivets or any other appropriate fasteners82. Alternatively, the base plate48may be welded or otherwise securely affixed to the bottom of the base slat46, or the base slat46and base plate48may be integrally formed as a single unitary component. The base slat48may further include one or more gaskets84attached to and extending along the bottom surface of the base plate48to form a seal with the surface of the opening when the shutter curtain30is closed. Similarly, one or more gaskets86may extend along the upper surface of the base plate to form a seal with the bottom wall19of the shutter housing when the shutter curtain30is fully rolled up.

At the upper edge of the base slat46, engagement members such as guide arms88extend outwardly from either end of the base slat46.FIG. 5illustrates the upper right portion of the shutter assembly10with the front wall16and bottom wall19removed, and the rolled up portion of the shutter curtain30being shown schematically. Additionally, for further clarity, the shutter supporter member20is not shown, and the side track40is shown in cross-section reflecting a section line passing through the end wall60and wall70. The guide arms88extend far enough from the ends of the base slat46to pass through the first gap66and the second gap72and into the channel defined by the fin68and wall70. The guide arms88may be connected to the base slat46by any appropriate mechanism, and may be formed from a material that is sufficiently strong so as not to bend when the guide arms88engage or are engaged by the side tracks40and the adjustable throw member78.

The end wall60and portions of the side walls56,58extend to the necessary height for insertion of the nipple80of the end cap14to position the shutter housing above or at the top of the opening. The portions of the side walls56,58on the side inward of the fin68and wall70may extend upwardly into the interior of the shutter housing by a distance that allows the shutter curtain to roll up onto the shutter support member20without interference, but sufficient to act as a guide for directing the slats32,46back into the side tracks when the shutter curtain is unrolled. The guidance function may be further promoted by bending the upper portion of the side wall56forward to open the top of the first and second channels of the side track40as shown in the side view ofFIG. 4.

The remaining portion of the side tracks40defined by the fin68, wall70and corresponding portions of the side walls56,58extend upwardly farther into the shutter housing. As shown inFIGS. 4 and 5, this upwardly extending portion of the side tracks40runs along the inside surface of the rear wall18and inward of the end cap14and drive motor housing42. The adjustable throw member78is disposed within this portion of the side track40. In the illustrated embodiment, the adjustable throw member78is implemented in the form of a bolt90and nut92that may be held in place within the side track by a bracket or cap94or other securement mechanism that will hold the bolt90in the normal position shown inFIGS. 4 and 5while allowing the bolt90to slide upwardly when engaged by the arm88of the base slat46as discussed further below. The adjustable throw member78may further include a biasing member such as spring96having one end engaging the head98of the bolt90and the other end secure relative to the side track40such as by the cap94or other attachment mechanism such that the spring96biases the bolt90toward the normal position and, if necessary, provides a force on the arm88to ensure that the base slat46moves downward in the side tracks40when the shutter curtain30is unrolled.

To ensure that the drive motor turns off when the shutter curtain30rolls up to the desired position, a limit switch100is mounted in the shutter housing and operatively connected to the drive motor.FIG. 6is a block diagram of one embodiment of the electrical components of the rolling shutter assembly10. A drive motor102may be disposed within the motor housing42and connected to the shutter support member20. In order to operate the drive motor102in either direction to raise and lower the shutter curtain30, a three-way switch104is operatively connected to the drive motor102and the limit switch100. Power for the drive motor102may be provided by a power source106, such as by a tie in to the building's electrical service. The three-way switch104may be any appropriate switch having a first position that will cause the drive motor102to rotate in the direction to roll up the shutter curtain30, a second position that will cause the drive motor102to rotate in the opposite direction, and a third position wherein the drive motor102is turned off. A single pole, center off switch is one example of an appropriate three-way switch104.

To control the position of the shutter curtain30as it is rolled up by the drive motor102, the limit switch100is positioned in the path between the drive motor102and the lead of the three-way switch104that will cause the drive motor102to wind the shutter curtain30. The limit switch100may be any appropriate electro-mechanical or electrical switch that is normally closed, or “push to break,” such that the limit switch100breaks contact and opens when the button or other mechanical actuation device is pressed, and reestablished contact to close the limit switch100when released. The drive motor102is illustrated as being directly connected to the lead of the three-way switch104that will cause the drive motor102to unwind the shutter curtain30, but those skilled in the art will understand that switches or other types of control or safety mechanisms may be installed along this path as well.

Returning toFIGS. 4 and 5, the shutter curtain30is partially unrolled so that the base slat46is disposed within the first channel of the side tracks40. In this position, the arm88of the base slat46is disengaged from the adjustable throw member78, and the limit switch100is in the normal closed position. When the three-way switch104is moved to the “UP” position ofFIG. 6, and with the limit switch100closed, the drive motor102is actuated to wind the shutter curtain30onto the shutter support member20. As the shutter curtain30winds, the base slat46eventually moves upwardly into the shutter housing. The portions of the side walls56,58of the side tracks40terminate to allow the slats32to roll up onto the shutter support member20. However, the arms88of the base slat46are engaged by the fins68and walls70of the side tracks40such that the base slat46continues to move vertically along the side tracks40.

As the base slat46continues to move vertically, the arm88engages the head98of the bolt90, forcing the bolt90upwardly against the force of the spring96as the spring96compresses between the head98and the cap94. The nut92moves upwardly with the bolt90and ultimately engages the actuator of the limit switch100. When the shutter curtain30is rolled up to its limit position as shown inFIGS. 7 and 8, the limit switch100is fully actuated to open the limit switch100and to turn off the drive motor102even if the three-way switch104remains in the “UP” position. The limit switch100may be positioned and the adjustable throw member78may be dimensioned so that the drive motor102turns off when the base slat46is almost completely disposed within the shutter housing. In this position, the gasket86on the upper surface of the base plate48may engage the bottom wall19of the shutter housing to cover the opening and present a clean, finished appearance. The upper limit for the shutter curtain30may be adjusted by moving the limit switch100up or down, or by loosening or tightening the nut92on the bolt90to change the distance between the nut92and the head98of the bolt90. Of course, those skilled in the art will appreciate that other configurations of throw members78and limit switches100may be implemented such that drive motor102may be shut off when the base slat46reaches a predetermined position, and such variations are contemplated by the inventor as having use in rolling shutter assemblies in accordance with the present disclosure.

To close the shutter curtain, the three-way switch104is moved to the “DOWN” position. Because the limit switch100is not in the path that controls the unwinding of the shutter curtain30, the drive motor102is actuated to rotate in the direction to unroll the shutter curtain30from the shutter support member20. Where the spring96or other biasing mechanism is provided, such as alternative spring arrangements or the addition of weights within the base slat46, the biasing force presses downwardly on the base slat46to ensure that the base slat46moves downward into the side track40for proper deployment of the shutter curtain30as it is unrolled. The shutter curtain30may be unrolled to the desired position, at which time the three-way switch104may be moved to the “OFF” position to turn off the drive motor102.

FIGS. 4-8illustrate an implementation of an electro-mechanical limit switch100having a spring biased arm mounted in the shutter housing for engagement by the throw assembly. However, the use of other types of switches detecting the disposition of the base slat46proximate the shutter housing is contemplated by the inventor. For example, a pneumatic switch may be implemented having an input that causes the switch to open when pressure at the input is increased due to engagement by the throw assembly or other component, such as the guide arm88of the base slat46. Still further, an optical switch may be implemented and positioned to detect a component of the rolling shutter assembly10arriving at a predetermined location when the shutter curtain30is fully rolled up and cause the motor to stop. Consequently, the electro-mechanical limit switch100ofFIGS. 4-8may be replaced by an optical switch having an eye positioned to detect when the nut92arrives at the position shown inFIGS. 7 and 8and shut off the motor.

Alternatively, the optical or other limit switch may be positioned to detect the arrival of the guide bar88at a predetermined position within the shutter housing. Referring toFIG. 9, the rolling shutter assembly10is modified to replace the electro-mechanical limit switch100ofFIGS. 4-8with an optical limit switch110mounted within the shutter housing proximate the side track40. The optical limit switch110may be operatively connected to the drive motor102, three-way switch104and power source106is a similar manner as described above with respect toFIG. 6. The optical limit switch110may have an eye112positioned at the location of the guide arm88when the base slat46reaches the desired location within the shutter housing. As the shutter curtain30is rolled up onto the shutter support member20, the guide arm88may engage the head98and compress the spring96to create the downward biasing force that will ensure that the base slat46and shutter curtain30properly unroll into the side tracks40. When the base slat46arrives at the position shown inFIG. 10, the eye112of the optical limit switch110may detect the guide arm88, and cause the optical limit switch110to open and thereby stop the drive motor102from rolling the shutter curtain30further. When the shutter curtain30is later unrolled, the guide arm88moves out of the position proximate the eye112, and the optical limit switch110may then close so that the drive motor102will again be able to operate to roll up the shutter curtain30.

In the embodiments discussed above, the limit switches in their various forms may be mounted to the housing walls during installation and subsequently connected to the drive motor102as shown inFIG. 6. Such an arrangement may be satisfactory in many implementations of the rolling shutter assembly10. However, installation may be further simplified by mounting a limit switch in the end cap14along with the drive motor housing42. This may allow the limit switch to be pre-installed and pre-wired within the end cap14at the factory, and the installers need only assembly the end caps14and walls12,16,18,19without having to wire the electrical components in the field. With the limit switch disposed within the end cap14, the end cap14, base slat46and shutter housing may be reconfigured to allow actuation of the limit switch when the base slat46arrives at the shutter housing.

FIGS. 11 and 12illustrate one embodiment of the shutter assembly10wherein a base plate120may have base plate extensions122and gasket124extending outwardly across the front of the side tracks40with base plate extensions122terminating proximate the end walls60and under the end caps14. At the outer portion of the base plate extension122disposed under the end cap14having a limit switch disposed therein, the base plate extension122may have a plunger126mounted thereon configured to actuate the limit switch when the base plate120is proximate the bottom of the shutter housing as will be described more fully below. The plunger126may be a separate component mounted to a top surface of the base plate120, or may be integrally formed with the base plate120as a single unitary component.

Referring toFIG. 13, the base plate extension122is shown approaching the bottom wall19of the shutter housing and the end cap14. The bottom wall19may have an opening128and a bottom wall of the end cap14may have a corresponding opening130aligned with the opening128and disposed above the plunger126. An electro-mechanical limit switch132may be mounted within the end cap14proximate the opening130, and may have an actuator arm134extending there from and overlying the openings128,130. The limit switch132may be operatively connected to the drive motor102as illustrated inFIG. 6and described in the accompanying text. As the base slat46and base plate120approach the bottom of the shutter housing, the plunger126is aligned with the openings128,130and able to pass through the openings128,130and engage the actuator arm134of the limit switch132. As shown inFIG. 14, the engagement of the plunger126may cause the actuator arm134to deflect upwardly and open the limit switch132, thereby shutting off the drive motor102. The limit switch132and plunger126may be dimensioned so that the gasket124engages the bottom wall19and forms a seal to close the opening of the shutter housing through which the shutter curtain30is dispatched and the openings128,130. Moreover, a majority of the force of engagement between the shutter housing and the base plate120may be taken up by the end caps14instead of the bottom wall19. Such engagement by the end caps14may reduce distortion of the shutter housing when the shutter curtain is rolled up, as the shutter housing in many installations is fabricated from relatively weak sheet metal that may easily deflect when a load is applied.

In alternative embodiments, the plunger126may be a component of the limit switch132. For example, the plunger126may be connected to or formed with the actuator arm134and extend downwardly through the openings128,130with an end disposed external to the shutter housing. As the base slat46approaches the shutter housing, the top surface of the base plate120may engage the end of the plunger126to push the actuator arm134upwardly and open the limit switch132.

Although not shown from the side views ofFIGS. 13 and 14, the bolt90and spring96may be disposed within the side tracks40as shown in the previous embodiments such that the guide arms88of the base slat46engages the head98, creating the downward force to ensure that the shutter curtain30unrolls into the side tracks40. Alternatively, the components of the adjustable throw member78may be moved into the end cap14along with the limit switch to provide the triggering of the limit switch and the spring force guiding the base slat46into the side tracks40.FIGS. 15 and 16show an embodiment implementing the adjustable throw member78into the end cap14. Referring toFIG. 15, the adjustable throw member78may be placed in the end cap14within a retention sleeve140and with the head of the bolt90aligned above the end cap opening130. The limit switch100may also be moved into the end cap14with the actuator of the limit switch100positioned above the nut92. As discussed above, the plunger126may be aligned with the end cap opening130so that the plunger126enters the end cap14through the opening130as the base slat46and base plate120approach the shutter housing. As the base slat46continues to move vertically, the plunger126engages the head98of the bolt90, forcing the bolt90upwardly against the force of the spring96as the spring96compresses between the head98and the cap94. The nut92moves upwardly with the bolt90and ultimately engages the actuator of the limit switch100.

When the shutter curtain30is rolled up to its limit position as shown inFIG. 16, the limit switch100is fully actuated to open the limit switch100and to turn off the drive motor102. The limit switch100may be positioned and the adjustable throw member78may be dimensioned so that the drive motor102turns off when the base plate120is proximate the bottom wall19of the shutter housing with the gasket124engaging the bottom wall19to cover the opening and present a clean, finished appearance. At the same time, the spring96provides a downward biasing force ensuring that the base slat46drops down into the side tracks40when the shutter curtain30is unrolled. A biasing mechanism may be positioned in the opposite end cap14if necessary to ensure balanced forces on either end of the base slat46, though the limit switch100need only be placed in one of the end caps14.

As discussed above, other configurations of throw members78and limit switches100may be implemented such that drive motor102may be shut off when the base slat46reaches a predetermined position, and such variations are contemplated by the inventor as having use in rolling shutter assemblies in accordance with the present disclosure. For example,FIG. 17illustrates an alternative embodiment wherein the plunger126may be disposed on the throw member78and extend downwardly through the opening130and extend below the bottom wall19of the shutter housing. The base plate120may engage the plunger126as the base slat46enters the shutter housing to actuate the limit switch100. In a similar manner with other embodiments discussed herein, a portion of a triggering mechanism for the limit switches may extend out of the shutter housing for engagement by the base slat46to stop the drive motor.

In further alternate embodiments, a biasing force on the base slat46may be provided through the limit switch actuation mechanism in a manner that eliminates the need for an additional spring mechanism within the end cap14. In one embodiment illustrated inFIGS. 18 and 19, the plunger126may be fabricated from a resilient material that may be compressed to create a spring force. Referring to FIG.18, the base plate120, the base plate extension122and the plunger126may be positioned relative to the openings128,130as discussed above in relation toFIGS. 13 and 14. In this embodiment, a limit switch in the form of a pressure switch150may be implemented and mounted within the end cap14with a pressure actuator152facing the openings128,130and plunger126. As the plunger126enters the end cap14through the openings128,130, the upper end of the plunger126engages the pressure actuator152of the pressure switch150. As base plate120is raised further, the resilient plunger126may compress and the pressure applied to the pressure actuator152may increase until the predetermined actuation pressure for the pressure switch150is reached. The plunger126may be configured and the pressure switch150may be selected and positioned so that the drive motor102is shut off when the base plate120reaches the upper limit position shown inFIG. 8with the gasket124engaging the bottom wall19of the shutter housing.

FIGS. 20 and 21show another embodiment of the plunger126having resiliency to provide the downward biasing force on the base slat46when the shutter curtain30is rolled up into the shutter housing. As shown inFIG. 20, the plunger126may have a multi-part construction including an outer resilient annular sleeve160and an inner finger162. The end cap14may be configured with an interior bracket164proximate the end cap opening130and having a bracket opening166having an inner diameter that is greater than an outer diameter of the finger162and less than an outer diameter of the annular sleeve160. In this embodiment, an optical limit switch168having an eye170may be implemented, though other types of limit switches may be used. As the base slat48approaches the shutter housing, the plunger126passes through the openings128,130and comes into contact with the bracket164. The bracket164is aligned so that the finger162of the plunger126may pass through the opening166while the annular sleeve160is engaged by a bottom surface of the bracket164. The annular sleeve160may be compressed between the bracket164and the base plate120as the finger162moves upwardly through the opening166. The compression of the annular sleeve160creates the downward force on the base slat46for forcing the base slat46down into the side tracks40when the shutter curtain30is unrolled. The finger162eventually reaches the position shown inFIG. 21wherein the eye170detects the presence of the finger162and causes the limit switch168to open and turn off the drive motor102.

In the preceding examples, the limit switches and triggering mechanisms, whether electrical, electro-mechanical, pneumatic, optical or the like, have been disposed in either the shutter housing or in the drive motor housing42of the end cap14. Those skilled in the art will understand that the portions of the shutter movement limiting mechanisms may be located in both the shutter housing and the motor housing42.FIGS. 22 and 23illustrate a further alternative embodiment of the rolling shutter assembly10wherein an electro-mechanical limit switch180may be mounted within the motor housing42, and have an actuator arm182extending through an opening184through an interior wall of the motor housing42to a position within the shutter housing between the side tracks40. The end of the actuator arm182may be disposed between front of the shutter curtain30and an edge of the bottom wall19, or over a hole through the bottom wall19. The plunger126is repositioned inwardly on the base plate120to align with the end of the actuator arm182. If desired, the base plate extensions122may be omitted. As the shutter curtain30is rolled up onto the shutter support member20, the base slat46approaches the rolled up portion of the shutter curtain30and the plunger126enters the shutter housing. The plunger126engages the actuator arm182and pushes the arm182upward until the limit switch180opens to shut off the drive motor at the position shown inFIG. 23. When the drive motor stops, the base slat46is positioned so that the gasket124may engage the bottom wall19of the shutter housing to close off the opening through which the shutter curtain30passes.

As with the other embodiments, the electro-mechanical limit switch180may be replaced by other types of switches capable of detecting the position of the base slat46, such as pneumatic or optical switches. These switches may have accompanying triggering mechanisms configured to actuation the switches when the plunger126enters the shutter housing. In other embodiments, the plunger may be mounted on the triggering mechanism and extend downwardly through an opening of the shutter housing and be engaged by the base slat46or base plate120to trigger the opening of the limit switch180. An optical switch may be positioned within the end cap14such that the entry of the plunger126into the shutter housing is detected without the need for an additional triggering mechanism. In these embodiments, installation of the limit switch180within the motor housing42of the end cap14allows the limit switch180to be prewired to the drive motor at the factory instead of the necessity of wiring the circuit in the field during installation, thereby simplifying the installation of the rolling shutter assembly10.