Patent Publication Number: US-9890582-B2

Title: Door release mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/286,832, filed May 23, 2014, issuing as U.S. Pat. No. 9,328,547 on May 3, 2016, which is a division of U.S. patent application Ser. No. 12/987,684, filed Jan. 10, 2011, now U.S. Pat. No. 8,770,255, which is a division of U.S. patent application Ser. No. 11/976,363, filed Oct. 24, 2007, now U.S. Pat. No. 7,878,230, the contents of each of the aforementioned patents are hereby incorporated by reference in their entireties. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to a door hoist. More particularly, the present invention pertains to a device and system for automatically releasing a door in response to an event. 
     BACKGROUND OF THE INVENTION 
     Conventionally, door hoist systems are utilized to operate a variety of doors. Particular examples of doors operated via a door hoist include rolling type, sectional, and the like. These types of doors are typically utilized for controlling access to garages, ware houses, etc. In the event of a fire, it is generally beneficial to close these doors to limit the amount of oxygen supplied to the fire and slow the spread of fire from one side of the door to the other. 
     Conventional electronic fire door systems are generally electronically or computer operated. Such systems are costly to design, install, and maintain. In addition, conventional electronic fire door systems are generally significantly larger than a standard door hoist. As such, retrofitting electronic fire door systems into an existing building may require structural alteration of the building. As a result, the installation and maintenance of electronic fire door systems may be cost prohibitive in some instances. 
     Accordingly, it is desirable to provide a method and apparatus capable of overcoming the disadvantages described herein at least to some extent. 
     SUMMARY OF THE INVENTION 
     The foregoing disadvantages are overcome, at least to a great extent, by the present invention, wherein in one respect, a device and system is provided that in some embodiments automatically releases a door in response to an event. 
     An embodiment of the present invention pertains to a door hoist to operate a door. The door hoist includes a bracket, drive sprocket, ring gear, hub assembly, set of planetary gears, and governor shaft. The drive sprocket has a drive sprocket axis and is fastened to a ring gear. The ring gear has a ring gear axis that is in alignment with the drive sprocket axis. The hub assembly includes a connector to receive a door drive shaft and secure the door drive shaft in a fixed rotational alignment with the hub assembly. The set of planetary gears is rotationally mounted to the hub assembly. The set of planetary gears is configured to mate with the ring gear. The governor shaft includes a sun gear, brake assembly, and link. The sun gear is configured to mate with the set of planetary gears. The brake assembly has an engaged position and a disengaged position. The sun gear is rotationally fixed relative to the bracket in response to the brake assembly being in the engaged position. In response to the brake assembly being in the disengaged position, rotation of the sun gear is unfixed relative to the bracket. The link secures the brake assembly in the engaged position. 
     Another embodiment of the present invention relates to a fire door hoist system to operate a door and automatically close the door in response to a fire. The fire door hoist system includes a door hoist and door release assembly. The door hoist operates the door. The door hoist includes a bracket, drive sprocket, ring gear, hub assembly, set of planetary gears, and sun gear. The drive sprocket has a drive sprocket axis and is fastened to a ring gear. The ring gear has a ring gear axis that is in alignment with the drive sprocket axis. The hub assembly includes a connector to receive a door drive shaft and secure the door drive shaft in a fixed rotational alignment with the hub assembly. The set of planetary gears is rotationally mounted to the hub assembly. The set of planetary gears is configured to mate with the ring gear. The sun gear is configured to mate with the set of planetary gears. The door release assembly automatically releases the door in response to the fire. The door release assembly includes a governor shaft, brake assembly, and link. The governor shaft is secured to the sun gear. The brake assembly has an engaged position and a disengaged position. The governor shaft is rotationally fixed relative to the bracket in response to the brake assembly being in the engaged position. In response to the brake assembly being in the disengaged position, the rotation of the governor shaft is unfixed relative to the bracket. The link secures the brake assembly in the engaged position. 
     Yet another embodiment of the present invention pertains to a door hoist to operate a door. The door hoist includes a bracket, drive sprocket, set of planetary gears, hub assembly, ring gear, and governor shaft. The drive sprocket has a drive sprocket axis and is rotationally fastened to the set of planetary gears. The set of planetary gears has an axis that is in alignment with the drive sprocket axis. The hub assembly includes a connector to receive a door drive shaft and secure the door drive shaft in a fixed rotational alignment with the hub assembly. The ring gear is fastened to the hub assembly. The ring gear is configured to mate with the set of planetary gears. The governor shaft includes a sun gear, brake assembly, and link. The sun gear is configured to mate with the set of planetary gears. The brake assembly has an engaged position and a disengaged position. The sun gear is rotationally fixed relative to the bracket in response to the brake assembly being in the engaged position. In response to the brake assembly being in the disengaged position, rotation of the sun gear is unfixed relative to the bracket. The link secures the brake assembly in the engaged position. 
     There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a door system according to an embodiment of the invention. 
         FIG. 2  is an exploded view of the hoist according to an embodiment of the invention. 
         FIG. 3  is a simplified view of a release assembly in an engaged position according to an embodiment of the invention. 
         FIG. 4  is a simplified view of the release assembly in a disengaged position according to the embodiment of  FIG. 3 . 
         FIG. 5  is a simplified view of a release assembly in an engaged position according to another embodiment of the invention. 
         FIG. 6  is a simplified view of the release assembly in a disengaged position according to the embodiment of  FIG. 5 . 
         FIG. 7  is a detailed view of a horizontally oriented actuator engaging a drive sprocket according to another embodiment of the invention. 
         FIG. 8  is a detailed view of a vertically oriented actuator engaging a drive sprocket according to yet another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In various embodiments of the invention a simplified device and system are provided to automatically release a door in response to an event. In a particular example, the device is configured to close a door in the event of a fire. For example, when attached to a door that is biased to close, a release assembly connecting a hoist assembly to the door assembly may be configured to release the door assembly from the hoist assembly in response to a fire or smoke. Released from the hoist assembly, the door may be allowed to close. In another example, the release assembly may be configured to release the door assembly from the hoist assembly in response to a security incident. In yet another example, the release assembly connects the hoist assembly to a door assembly that is biased to open. In this example, the release may be controlled to release the door assembly from the hoist assembly to facilitate egress through the door. In comparison to electronically controlled or computer controlled door closing systems, this simplified device is easier, less expensive, and less time consuming to manufacture. For the consumer, this simplified device is easier and less expensive to install and maintain in comparison to electronically controlled door closing systems. 
     An embodiment of the invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. As shown in  FIG. 1 , a door system  10  includes a door  12  and a hoist  14 . The door  12  may include any suitable door or other such covering structure operable to cover an opening. In general, the door  12  may include rollup, swing, sliding, etc. type doors. In a particular example, the door  12  is a conventional rollup type door configured to slide within a track  16  and roll up into a cover  18 . Such rollup type doors are well known to include a cylinder or shaft within the cover  18  to operate the door  12 . That is, the door  12  is drawn into the cover  18  by rotating the shaft and rolling the door about the shaft or a cylinder connected to the shaft. The door  12  is controlled or allowed to close by rotating the shaft in the opposite direction and/or allowing gravity to draw the door  12  downwards. In this regard, the door  12  is biased in the closed position. A door that is otherwise suitable for use with various embodiments of the invention but is not biased in the closed position may be modified to be biased in the closed position. For example, a spring or weight or other such door closing device may be added to the door. 
     The hoist  14  according to various embodiments may be operated via any suitable mechanism. In several particular examples shown in insets A, B, and C, the hoist  14  may include a chain drive  20  or motor  22  and the motor  22  may be mounted vertically or horizontally. A particular example of the chain drive  20  is shown in  FIG. 2 . Particular examples of vertically and horizontally mounted motors  22  are shown respectively shown in  FIGS. 5 and 6 . 
       FIG. 2  is an exploded view of the hoist  14  according to an embodiment of the invention. As shown in  FIG. 2 , the hoist  14  includes a chain hoist wheel assembly  24 , unidirectional brake assembly  26 , drive assembly  28 , door release assembly  30 , and bracket  32 . The chain hoist wheel assembly  24  is optional and in this or other embodiments, any suitable actuator may be substituted. For example, the motor  22  may replace the chain hoist assembly  28 . If present, the chain hoist assembly  24  includes a chain  34 , chain hoist wheel  36 , chain drive sprocket  38 , chain guards  40 , and chain hoist shaft  42 . To operate the door  12 , the chain  34  may be pulled by a user to urge the chain hoist wheel  36  to rotate. The chain drive sprocket  38  is integral to or fastened to the chain hoist wheel  36 . As a result, rotation of the chain hoist wheel  36  induces a corresponding rotation of the chain drive sprocket  38 . In turn, operation of the chain hoist wheel assembly  24  urges the drive assembly  28  to raise or lower the door  12 . As is generally known, inducing a rotation of the drive assembly  28  in a first direction causes the door  12  to raise and inducing an opposite rotation causes the door  12  to lower. 
     The unidirectional brake assembly  26  is optionally included to accompany actuating assemblies that lack sufficient self-braking characteristics. If present, the unidirectional brake assembly  26  includes a brake pressure plate  44 , brake pad  46 , ratcheted pressure plate  48 , spring  50 , pawl  52 , and mounting plate  54 . The brake pressure plate  44 , brake pad  46 , ratcheted pressure plate  48 , and spring  50  are mounted to the chain hoist shaft  42 . The brake pressure plate  44  is pinned or otherwise fixed to rotate with the chain hoist shaft  42 . The pawl  52  is mounted to the mounting plate  54  or the bracket  32 . The ratcheted pressure plate  48  includes one or more detents or teeth to engage the pawl  52 . In this manner, the ratcheted pressure plate  48  is configured to rotate in a first direction and the ratcheted pressure plate  48  is stopped from rotating in a reverse rotational direction by the interaction of the pawl  52  and teeth. 
     The chain hoist wheel assembly  24  shown in  FIG. 2  may provide so little rotational resistance that, barring additional intervention, the door  12  may tend to fall closed. To reduce this tendency, the unidirectional brake assembly  26  is configured to provide resistance to rotation which results in a downward movement of the door  12 . To ease the operation of raising the door  12 , the unidirectional brake assembly  26  rotates substantially freely in the direction of rotation that raises the door  12 . 
     In other instances, the chain hoist wheel assembly  24 , motor  22 , or other such actuator may provide sufficient rotational resistance to retain the door  12  in an open position. For example, a worm gear (shown in  FIG. 6 ) may be employed to urge the drive assembly  28  to rotate. The direction of torque transmission (input shaft vs. output shaft) is not reversible in conventional worm gear trains. In this or other such instances, the unidirectional brake assembly  26  may be omitted. 
     The drive assembly  28  according to various embodiments provides a simplified gear train in comparison to conventional door hoists. This simplified gear train reduces the material and labor costs, reduces the size of the hoist  14 , and may increase reliability. It is a further advantage of the drive assembly  28  that the door release assembly  30  is fully integrated into this simplified gear train and shares components therewith. This further simplifies the door system, which results in a further reduction of material and labor costs. 
     As shown in  FIG. 2 , the drive assembly  28  includes a drive sprocket  56 , annulus or ring gear  58 , sun gear  60 , set of planetary gears  62 , hub assembly  64 , and connector  66 . The drive sprocket  56  is arranged or configured to mate with the chain drive sprocket  38  or similar such gear of the motor  22  or other such actuator. In an embodiment, the ring gear  58  is integral to or fixed to the drive sprocket  56 . In a particular example, the ring gear  58  is welded to the drive sprocket  56  with a central or rotational axis of the ring gear  58  coinciding with a central axis of the drive sprocket  56 . The sun gear  60  is disposed to coincide with the central axis of the ring gear  58 . The set of planetary gears  62  is disposed between the ring gear  58  and the sun gear  60  and configured to mate with both. While the number of individual planetary gears in the set of planetary gears  62  may vary, such gear trains typically include at least a pair, and more typically four, individual planetary gears to balance and distribute loads throughout the gear train. The hub assembly  64  may serve as a planet carrier for the set of planet gears  62 . In this capacity, the ring gear  58  functions as the input shaft, the rotation of which causes the set of planet gears  62  to rotate about a fixed sun gear  60  and the hub assembly  64  is the output shaft to operate the door  12 . In this regard, the connector  66  is fixed to the hub assembly  64 . The connector  66  is configured to receive and rotationally secure a door shaft  68 . The door shaft  68  operates the door  12  and may be secured to the connector  66  in any suitable manner. In a particular example, the door shaft  68  includes a channel for a spline  67 , the connector  66  includes a channel for the spline  67 , and the door shaft  68  and connector  66  are locked in rotational alignment by the insertion of the spline  67  into the channel. In other examples, the door shaft  68  and connector  66  may include mating “D” or square configurations, and/or may be welded, press fit, or otherwise fastened together. 
     In another embodiment, the ring gear  58  is integral to or fixed to the hub assembly  64  and the set of planetary gears  62  are rotationally mounted to the sprocket  56 . That is, the sprocket  56  may serve as a planet carrier for the set of planet gears  62 . In addition, other arrangements of the gear train are within the scope of the invention. 
     The door release assembly  30  includes a governor shaft  70 , governor  72 , plate  74 , drop arm  76 , and link  78 . The governor shaft  70  is secured to the sun gear  60 . In various examples, the sun gear  60  may be press fit, pinned, splined, or otherwise fixed to the governor shaft  70 . The governor  72  includes any suitable governing device such as, for example, a viscous governor, mechanical, brake-type governor, and the like. The governor  72  includes a hub that is fixed to the governor shaft  70 . The plate  74  is secured to the governor shaft  70 . In various examples, the plate  74  may be press fit, pinned, splined, or otherwise fixed to the governor shaft  70 . The plate  74  includes at least one point or tooth configured to engage a corresponding point, indent, or tooth on the drop arm  76 . The drop arm  76  includes two ends. A first end is pivotally fixed with respect to the plate  74 . The second end is secured via the link  78 . In this secured position, the drop arm  76  and the plate  74  are configured to preclude rotation of the governor shaft  70 . In response to removal of the link  78  or loss of structural integrity of the link  78 , the drop arm  76  is allowed to swing or pivot about the first end and disengage from the plate  74 . In this disengaged position, the plate  74  and therefore the governor shaft  70  are free to rotate. 
     According to an embodiment of the invention, at a predetermined temperature, the link  78  is configured to soften, melt, or otherwise lose sufficient structural integrity to retain the drop arm  76 . The predetermined temperature may be set according to a variety of factors. These factors may include, for example, expected normal ambient temperature, manufacture&#39;s recommendation, empirical data, and the like. To facilitate manual operation and/or testing of the door system  10 , the link  78  may be attached to the drop arm  76  via a line  80  and the line  80  may be attached to a handle or switch  82 . As shown in  FIGS. 4 and 5 , the switch  82  may be moved from a first to a second position to control the drop arm  76 . In another example, the link  78  may pass through a hole in the bracket  32  to secure the drop arm  76  and a ring or handle may remain outside of a housing. In this manner, the ring provides a gripping surface to remove the link  78  and is readily available to test the door system  10 . 
     According to another embodiment, the link  78  may include an electronic release device such as, for example, an electromagnetically coupled link, solenoid release device, or the like. In this embodiment, the link  78  may release the drop arm  76  in response to any suitable event such as, for example, a smoke alarm activation, security event, manual activation of a switch, and the like. 
       FIG. 3  is a simplified view of the drop arm  76  and plate  74  in the engaged position according to  FIG. 2 . As shown in  FIG. 3 , the drop arm  76  is secured to the link  78  via the line  80 . In addition, the switch  82  is shown in a first configuration. In this first configuration, the line  80  is controlled to retain the drop arm  76  in the engaged position. When secured in the engaged position, the drop arm  76  and plate  74  lock together to prevent the plate  74  from turning. In turn, the governor shaft  70  is prevented from turning by the engaged plate  74 . That is, the governor shaft  70  is rotationally fixed relative to the bracket  32  in response to the door release assembly  30  being in the engaged position. 
       FIG. 4  is a simplified view of the drop arm  76  and plate  74  in the disengaged position according to  FIG. 2 . As shown in  FIG. 4 , in response to disposing the switch  82  in a second position or compromising the structural integrity of the link  78 , the drop arm  76  is configured to drop from the engaged position. As the drop arm  76  pivots away from the plate  74 , the plate  74  is free to rotate. In this manner, the door release assembly may be controlled to release the door  12 . Depending upon the bias of the door  12 , releasing the release assembly may raise or lower the door  12 . In a particular example, the door  12  may be biased to close and the door system  10  is configured to automatically close the door  12  in response to the ambient temperature exceeding the predetermined temperature. It is an advantage of the door system  10  that this automatic closure may proceed in a complete absence of electrical power. It is another advantage of the door system  10  that this automatic closure may proceed even if the chain drive  20  or motor  22  is disabled. It is a further advantage of the door system  10  that the system is easier and less expensive to maintain than an electronically controlled door closing system. 
     In another example, the link  78  may be electronically controlled to disassemble or otherwise release the line  80 . In this example, the link  78  may be controlled to release the line  80  in response to the activation of a smoke alarm or security system activation. 
     In yet another example, the door  12  may be biased to fully or partially open. For example, in response to the drop arm  76  being released, a closed door  12  may be allowed to fully or partially open. In a particular example, if the door  12  provides an egress for a facility and the door  12  is closed, the door release assembly  30  may be automatically or manually controlled to release to door  12 . In this manner, egress through the door  12  may be facilitated. 
       FIG. 5  is a simplified view of the drop arm  76  and plate  74  in the engaged position. As shown in  FIG. 5 , the drop arm  76  includes a pivot point  90  and a link point  92 . The pivot point  90  may be pivotally connected to the bracket  32  or other such structural member via a shaft, bolt, rivet, or the like. The link point  92  is secured via the link  78  to the bracket  32  or other such structural member of the door system  10 . When secured in the engaged position, the drop arm  76  and plate  74  lock together at an engagement interface  84  to prevent the plate  74  from turning. In turn, the governor shaft  70  is prevented from turning by the engaged plate  74 . That is, the governor shaft  70  is rotationally fixed relative to the bracket  32  in response to the door release assembly  30  being in the engaged position. 
     As shown in  FIGS. 2, 3, and 4 , the link  78  may be secured to the link point  92  via a line  80 . In another embodiment, the link  78  may be inserted through the link point  92  and into the bracket  32  or other such structural member. In this embodiment, by altering an angle of the engagement interface  94 , the torque being applied to the plate  74 , and a length relationship between the pivot point  90 , engagement interface  94 , and link point  92 , an amount of sheer force exerted upon the link  78  may be adjusted. By configuring the structural integrity of the link  78  to fall below the sheer force at the predetermined temperature, the drop arm  76  may be controlled to disengage at the predetermined temperature. 
       FIG. 6  is a simplified view of the drop arm  76  and plate  74  in the disengaged position according to  FIG. 5 . As shown in  FIG. 6 , in response to removal of the link  78  from the link point  92  or the structural integrity of the link  78  failing or falling below the sheer force exerted on the link  78 , the drop arm  76  is configured to drop from the engaged position. As the drop arm  76  pivots away from the engagement interface  94  (shown in  FIG. 2 ) the plate  74  is free to rotate. 
     As shown in  FIG. 2 , the free rotation of the plate  74  decouples the drive sprocket  56  from the drive assembly  28 . That is, the rotational relationship between the drive sprocket  56  and the hub assembly  64  is decoupled. As such, the door  12  is free to close or open in accordance with the bias of the door  12 . To control the rate at which the door  12  opens or closes, the rotation of the governor shaft  70  is controlled by the governor  72 . In this regard, a hub of the governor  72  is secured to the governor shaft  70  and a housing of the governor  72  is secured to the bracket  32  or suitable structural member. The hub and housing of the governor  72  interact with one another via a viscous fluid or other such braking mechanism. The degree to which the governor  72  slows rotation of the governor shaft  70  may be determined based upon a variety of factors such as, for example, weight or closing bias of the door, fire door closing regulations, empirical data, and the like. 
       FIG. 7  is a detailed view of a horizontally oriented actuator engaging the drive sprocket  56  according to another embodiment of the invention. As shown in  FIG. 7 , the door system  10  includes a motor sprocket  96  that is rotated by the motor  22 . In various embodiments, the motor sprocket  96  may directly engage the drive sprocket  56  or, as shown in  FIG. 5 , a chain  98  may engage both the motor sprocket  96  and the drive sprocket  56  and may be configured to transmit rotation of the motor sprocket  96  to the drive sprocket  56 . In another example, the motor sprocket  96  and the drive sprocket  56  may be replaced with pulleys and the chain  98  may be replaced with a belt. These and other such transmission systems are within the purview of various embodiments of the invention. 
       FIG. 8  is a detailed view of a vertically oriented actuator engaging a drive sprocket  56  according to yet another embodiment of the invention. As shown in  FIG. 6 , the door system  10  includes a worm gear  100  that is rotated by the action of the motor  22 . The worm gear  100  is configured to engage the drive sprocket  56  and urge the drive sprocket  56  to rotate in response to rotation of the worm gear  100 . It is an advantage of such a worm drive that rotation is unidirectionally transmitted. 
     The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.