Patent Grant
8397787
The present invention generally relates to a door mechanism. More particularly, the present invention pertains to a device and system for automatically releasing a door in response to an event.
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.
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 mechanism. The door mechanism includes a bracket and a door shaft to operate a door. The door shaft is rotationally mounted to the bracket. The door shaft rotates in a first direction in response to the door being raised. The door shaft rotates in a second direction in response to door being lowered and the door is biased to close. The door mechanism includes a gear assembly having a ring gear, set of planetary gears, sun gear, and drive sprocket. The ring gear fixed to the door shaft. The set of planetary gears is mated to the ring gear and a set of respective axes of the set of planetary gears being fixed relative to the bracket. The sun gear is mated to the set of planetary gears and the drive sprocket is fixed to the sun gear. The door mechanism includes a holding brake to counter the closing bias of the door. The holding brake includes a holding brake sprocket, freewheel, and first brake. The holding brake sprocket is rotationally coupled to the drive sprocket. The freewheel is coupled to the holding brake sprocket to facilitate free rotation of the door shaft in the first direction. The first brake is coupled to the holding brake sprocket via the freewheel to provide resistance to rotation of the door shaft in the second direction. The door release has an engaged position and a disengaged position. In response to the door release being in the engaged position, rotation of the door shaft in the second direction is impeded by the first brake. In response to the door release being in the disengaged position, rotation of the door shaft in the second direction is unimpeded by the first brake. The door mechanism includes a link and a second brake. The link is to secure the door release in the engaged position and is configured to melt in response to an ambient temperature exceeding a predetermined temperature. The second brake has a brake sprocket rotationally coupled to the drive sprocket. The second brake is configured to provide resistance to the brake sprocket in response to rotation of the brake sprocket exceeding a predetermined braking speed.
Another embodiment of the present invention relates to a door mechanism. The door mechanism includes a bracket and a door shaft to operate a door. The door shaft is rotationally mounted to the bracket. The door being raised in response to the door shaft rotating in a first direction. The door being lowered in response to the door shaft rotating in a second direction and the door being biased to close. The door mechanism includes a gear assembly having a first gear, second gear, and drive sprocket. The first gear is fixed to the door shaft. The second gear is mated to the first gear and the second gear is fixed to an operating shaft configured to receive a crank-arm. The drive sprocket is fixed to the door shaft. The door mechanism includes a holding brake to counter the closing bias of the door which includes a holding brake sprocket, freewheel, and first brake. The holding brake sprocket is rotationally coupled to the drive sprocket. The freewheel is coupled to the holding brake sprocket and the freewheel is configured to provide free rotation of the holding brake sprocket in the first direction. The first brake is coupled to the holding brake sprocket via the freewheel. The door mechanism includes a door release having a release cog, brake drive sprocket, and drop arm. The release cog is coupled to the holding brake sprocket via the first brake. The brake drive sprocket is fixed the release cog and the drop arm has a tooth to mesh with the release cog. The drop arm has an engaged position and a disengaged position. In response to the drop arm being in the engaged position, rotation of the brake drive sprocket is prevented. In response to the drop arm being in the disengaged position, rotation of the holding brake sprocket in the second direction urges the brake drive sprocket to rotate. The door mechanism includes a link and second brake. The link is to secure the drop arm in the engaged position and is configured to melt in response to an ambient temperature exceeding a predetermined temperature. The second brake has a brake sprocket rotationally coupled to the brake drive sprocket. The second brake is configured to provide resistance to rotation of the brake sprocket in response to rotation of the brake sprocket exceed a predetermined braking speed.
Yet another embodiment of the present invention pertains to a door mechanism. The door mechanism includes a bracket and a door shaft to operate a door. The door shaft is rotationally mounted to the bracket. The door shaft rotates in a first direction in response to the door being raised. The door shaft rotates in a second direction in response to door being lowered and the door is biased to close. The door mechanism include a drive sprocket fixed to the door shaft and attached to a holding brake assembly to counter the closing bias of the door. The holding brake assembly includes a holding brake sprocket, freewheel, and first brake. The holding brake sprocket is rotationally coupled to the drive sprocket. The freewheel is coupled to the holding brake sprocket and configured to provide free rotation of the holding brake sprocket in the first direction. The first brake is coupled to the holding brake sprocket via the freewheel. The first brake provides resistance to rotation of the holding brake sprocket in the second direction. The door mechanism includes a door release having a release cog, brake drive sprocket, and drop arm. The release cog is coupled to the holding brake sprocket via the first brake. The brake drive sprocket is fixed the release cog. The drop arm has a tooth to mesh with the release cog. The drop arm has an engaged position and a disengaged position. In response to the drop arm being in the engaged position, rotation of the brake drive sprocket is prevented. In response to the drop arm being in the disengaged position, rotation of the brake drive sprocket is unimpeded by the release cog. The door mechanism includes a link and a second brake. The link is to secure the drop arm in the engaged position. The link is configured to melt in response to an ambient temperature exceeding a predetermined temperature. The second brake has a brake sprocket rotationally coupled to the brake drive sprocket. The second brake is configured to provide resistance to rotation of the brake sprocket in response to rotation of the brake sprocket exceed a predetermined braking speed.
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.
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
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
The holding brake assembly 26 is optionally included to accompany actuating assemblies that lack sufficient self-braking characteristics. If present, the holding 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
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
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
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, drop wheel 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 drop wheel 74 is secured to the governor shaft 70. In various examples, the drop wheel 74 may be press fit, pinned, splined, or otherwise fixed to the governor shaft 70. The drop wheel 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 drop wheel 74. The second end is secured via the link 78. In this secured position, the drop arm 76 and the drop wheel 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 drop wheel 74. In this disengaged position, the drop wheel 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'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
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.
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.
As shown in
As shown in
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.
The holding brake sprocket 112 is fixed to the pressure plate 44 such that the holding brake sprocket 112 and the pressure plate 44 rotate in unison. The brake pad 46 is sandwiched between the pressure plate 44 and a pressure plate 120. The pressure plate 120 is rotationally fixed to the drop wheel 74 via a freewheel 132 as shown in
The brake sprocket 116 is rotationally coupled to both the drive sprocket 56 and the holding brake sprocket 112 via the chain 118. Rotation of the brake sprocket 116 rotates an internal mechanism of the centrifugal brake 114. The centrifugal brake 114 may include a conventional centrifugal brake. That is, rotation of the brake sprocket 116 causes spring loaded, weighted, brake pads to rotate and generate a centrifugal force that is opposed by the spring. At a predetermined rotational speed, the centrifugal force overcomes the spring force and the weighted brake pads are urged against an inside housing. The resulting friction slows or urges against the rotation of the brake sprocket 116.
In response to the door 12 being raised, the door shaft 68 is rotated in direction “A” which, as shown in
In an embodiment, the holding brake assembly 26 is decoupled from rotation of the drive sprocket 56 in direction B. For example, in response to the holding brake sprocket 112 rotating in direction B and by virtue of a freewheel 132, the holding brake assembly 26 is allowed to freely rotate on the shaft 130 in direction B. In the particular example shown in
In an embodiment, the raising of the door 12 urges the brake sprocket 116 to rotate in direction B. However, in this or other embodiments, rotation of the brake sprocket 116 may be decoupled from rotation of the various other components of the door mechanism in response to the door 12 being raised. For example, the freewheel 132 may be utilized to decouple rotation of the brake sprocket 116 from the drive sprocket 56.
In response to the door 12 being lowered, the door shaft is urged to rotate in direction B and, via transmission through the drive assembly 28, the drive sprocket 56 is urged to rotate in direction A. This rotation of the drive sprocket 56 in direction A urges the chain 118 in direction A and the holding brake sprocket 112 and brake sprocket 116 are urged to rotate in direction A via the chain 118. In response to the drop arm 76 being in the engaged position, the drop wheel 74 is held fixed and prevented from rotating upon a shaft 130. The freewheel 132 is configured to prevent rotation in direction A which, in turn, prevents the pressure plate 120 from rotating. As such, rotation of the holding brake sprocket 112 and pressure plate 44 is prevented until the torque exerted upon the holding brake sprocket 112 overcomes the frictional resistance provide by the brake pad 46 sandwiched between the pressure plate 44 and pressure plate 120. To adjust the frictional resistance, a jam nut 134 may be tightened or loosened upon the shaft 130. In addition, one or more springs or Belleville washers 136 may be included to facilitate providing a predetermined “pre-loaded” compressive force upon the pressure plate 44.
The holding brake sprocket 112 is fixed to the freewheel 132 such that the holding brake sprocket 112 and the freewheel 132 rotate in unison. The brake pad 46 is sandwiched between the pressure plate 44 and the drop wheel 74. The drop wheel 74 is rotationally fixed to a brake drive sprocket 160. The brake drive sprocket 160 is mated or coupled to the centrifugal brake 114 via a chain 162, for example. It is an advantage of this embodiment that the centrifugal brake 114 is not driven so long as the drop arm 76 is in the engaged position. That is, the holding brake sprocket 112 is rotationally coupled to the drive sprocket 56 via the chain 118 and the holding brake sprocket 112 is rotationally coupled to the brake drive sprocket 160 via the freewheel 132 and holding brake assembly 26. However, as long as the drop wheel 74 is fixed by the drop arm 76, rotation of the holding brake sprocket 112 does not result in rotation of the brake drive sprocket 160. In particular examples, in response to the door 12 being raised, the freewheel 132 is configured to allow the holding brake sprocket 112 to rotate freely in direction A. In response to the door 12 being lowered, rotation of the holding brake sprocket 112 in direction B is translated through the freewheel 132 and to the holding brake assembly 26. If the torque applied to the holding brake sprocket 112 exceeds a predetermined maximum amount of torque, resistance of the holding brake assembly 26 is overcome such that the brake pressure plate 44 is allowed to rotate relative to the drop wheel 74 until the torque applied to the holding brake sprocket 112 falls below the predetermined amount of torque.
In response to the drop arm 76 being in the disengaged position, rotation of the holding brake sprocket 112 in direction B is translated through the holding brake assembly 26 to the brake drive sprocket 160 and, via the chain 162, to the brake sprocket 116. Rotation of the brake sprocket 116 rotates an internal mechanism of the centrifugal brake 114. The centrifugal brake 114 may include a conventional centrifugal brake. That is, rotation of the brake sprocket 116 causes spring loaded, weighted, brake pads to rotate and generate a centrifugal force that is opposed by the spring. At a predetermined rotational speed, the centrifugal force overcomes the spring force and the weighted brake pads are urged against an inside housing. The resulting friction slows or urges against the rotation of the brake sprocket 116.
To facilitate a controlled descent of the door 12, the centrifugal brake 114 is configured to resist rotation of the brake sprocket 116 in response to the brake sprocket 116 exceeding a predetermined maximum speed of rotation. In a particular example, the predetermined maximum speed of rotation is 830 revolutions per minute (RPM). To achieve this speed, the drive assembly 28 is configured to increase the rotational speed of the door shaft 68. In a particular example, the gear ratio between the drive sprocket 56 and the holding brake sprocket 112 is about 4:1 and the gear ratio between the brake drive sprocket 160 and the brake sprocket 116 is about 3:1 for an overall gear ratio of about 12:1.
The worm assembly 152 includes any suitable gear system operable to generate sufficient mechanical advantage. In the case of a human operated door mechanism 110, an about 20:1 to about 30:1 gear ratio may be suitable. Conventional worm gear systems are particularly suitable for generating such ratios. Generally, worm gear systems are unidirectional. That is, turning the worm urges the worm gear to rotate, while urging the worm gear to rotate does not typically cause a conventional, single start, worm to rotate. However, by altering the angle at which the teeth mesh at, a worm gear system or the like may be driven in either direction. For example, a two or three start worm may be turned by rotation of the worm gear. Similarly, helical gear assemblies, spiral bevel gear assemblies, hypoid gear assemblies, and/or the like may be driven in either direction. In the particular example shown, the worm assembly 152 includes a worm 164 and worm gear 166. The worm 163 is fixed to the worm shaft 154. The worm gear 166 is fixed to the door shaft 68. In response to the drop arm 76 being in the disengaged position, the closing bias of the door 12 is configured to drive the drive assembly 28, including the worm assembly 152, in reverse.
In response to the drop arm 76 being in the disengaged position, rotation of the holding brake sprocket 112 in direction B is translated through the holding brake assembly 26 to the brake drive sprocket 160 and, via the chain 162, to the brake sprocket 116. Rotation of the brake sprocket 116 rotates an internal mechanism of the centrifugal brake 114. The centrifugal brake 114 may include a conventional centrifugal brake. That is, rotation of the brake sprocket 116 causes spring loaded, weighted, brake pads to rotate and generate a centrifugal force that is opposed by the spring. At a predetermined rotational speed, the centrifugal force overcomes the spring force and the weighted brake pads are urged against an inside housing. The resulting friction slows or urges against the rotation of the brake sprocket 116.
To facilitate a controlled descent of the door 12, the centrifugal brake 114 is configured to resist rotation of the brake sprocket 116 in response to the brake sprocket 116 exceeding a predetermined maximum speed of rotation. In a particular example, the predetermined maximum speed of rotation is 830 RPM. To achieve this speed, the drive assembly 28 is configured to increase the rotational speed of the door shaft 68. In a particular example, the gear ratio between the drive sprocket 56 and the holding brake sprocket 112 is about 70:15 and the gear ratio between the brake drive sprocket 160 and the brake sprocket 116 is about 3:1 for an overall gear ratio of about 14:1.
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.
This application claims the benefit of, U.S. Provisional Patent Application Ser. No. 61/170,888 filed Apr. 20, 2009, entitled DOOR RELEASE MECHANISM, the disclosure of which is incorporated herein by reference in its entirety.
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