Patent Grant
10851798
The basic powered blade deployment of a ceiling fan is covered by U.S. Pat. No. 7,857,591 B2, which is incorporated in its entirety here by this reference. The individual fan blades are mounted to a rotating platform that is powered by a main fan motor. Development of the technology for commercial use has depended upon a good solution for transmitting controllable power to this rotating platform, for precisely actuating the fan blades.
Initial designs used one or more electric motors on the rotating platform to actuate the blades. This relied on a rotating electrical interface, or slip ring. This approach is lacking because slip rings tend to be expensive and wear out too quickly for the expected life of a ceiling fan. There is also a problem with coordinating the deployment of the blades, and with corrosion of the slip ring contacts during typical long periods when the fan is not used.
A first approach to an alternative power source for the blades is described in our second patent—U.S. Pat. No. 8,864,463 B2, which is incorporated in its entirety here by this reference. This approach uses the main fan motor mounted to a planetary gear set. When the planetary gears are locked, the fan rotates as a unit. When the planetary gears are unlocked, the rotating platform can be locked and the main motor planet carrier drives the blade deployment and retraction in a coordinated fashion. This approach has proven to work, but is difficult to implement into a commercial product. The required clutches are noisy, prone to wear, and difficult to control accurately. Coordinating the main motor speed in all conditions in order to ensure smooth blade action has been a challenge with this design. In short, this approach has not given the quality experience customers would expect from a high-end ceiling fan.
After the main motor/planetary gear drive experience, extensive research resulted in a blade actuation solution that accomplishes the following objectives: low cost, durable, low energy consumption (Energy Star rating is desirable in the industry), plenty of power to actuate blades of various sizes, good coordination and control of blades, low or minimal adjustments over the life of the product, easy to operate as part of a normal ceiling fan remote control, excellent sound quality in line with a high-end product, no rotating electrical interface, compact size to allow for a variety of housing designs.
The new fan actuator and structure described here meets all of these requirements by coupling radial deployment of fan blades using a linear actuator while the fan blades or rotating. The fan blades can further be pitched up during deployment. When the fan is turned off and the fan blades return to their stowed configuration, the fan blades automatically pitch down until flat as the fan blades retract radially back into a housing.
The detailed description set forth below in connection with the appended drawings is intended as a description of presently-preferred embodiments of the invention and is not intended to represent the only forms in which the present invention may be constructed or utilized. The description sets forth the functions and the sequence of steps for constructing and operating the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention.
The invention of the present application is a system and method of automatically deploying and stowing one or more fan blades 120 by moving a carriage 104 in a first linear direction along a linear actuator 102 mounted to a fan motor 122, wherein the carriage 104 is operatively connected to the fan blade to rotate with the fan blade 120. Moving the carriage 104 in the first linear direction converts the linear movement of the carriage 104 in the first linear direction into movement of the fan blade 120 in a first radial direction away from the linear actuator, and moving the carriage 104 in a second linear direction along the linear actuator 104, opposite the first linear direction converts the movement of the carriage in the second linear direction into movement of the fan blade in a second radial direction towards the linear actuator. In some embodiments, movement of the fan blade in the first radial direction pitches the fan blade up; and movement of the fan blade in the second radial direction pitches the fan blade down. In some embodiments, movement of the carriage in the first linear direction causes housing sections 138a, 138b of a housing 138 to separate and reveal the fan blade 120; and movement of the carriage 104 in the second linear direction causes the housing sections 138a, 138b to mate together to hide the fan blade 120 inside the housing.
As shown in
As shown in
These units are easily controlled, provide substantial force at various speeds, and have pleasing sound quality. In the preferred embodiment, less than 10 watts of electrical power is required to completely deploy and retract fan blades 120, including a fan blade with a 58 inch diameter. Most importantly, the drive element is inexpensive, readily available, and has a service life over 1 million actuation cycles. This life is essentially infinite in a fan deployment application.
With the actuator 102 rigidly mounted on the central axis A of the fan 100 and driving a rotatable carriage 104 up and down along the central axis A of the fan 100, it is necessary to transmit that carriage motion into movement of fan blades 120. In the preferred embodiment, this is accomplished by operatively connecting the carriage 104 to the fan platform 108 to convert the vertical motion of the carriage 104 into a radial motion of the fan blades 120 towards and away from the central axis A of the fan 100. For example, the carriage is operatively connected to the fan platform to convert movement of the carriage in a first linear direction into movement of the fan blade in a first radial direction away from the central axis, and to convert movement of the carriage in a second linear direction, opposite the first linear direction, into movement of the fan blade in a second radial direction towards the central axis.
With reference to
The deployment system 128 comprises an arm 130 and a sliding block 132. The arm 130 comprises a first end 134 and a second end 136 opposite the first end 134. The first end 134 of the arm 130 is connected to the carriage 104 and the second end 136 of the arm is connected to the sliding block 132. The number of arms 130 and sliding block 132 are determined by the number of fan blades 120. Each fan blade 120 would have associated with it, one arm 130 and one sliding block 132. Therefore, for a two-blade fan as shown in the figures, there would be two arms 130a, 130b and two sliding blocks 132a, 132b. For ease of description, deployment of a single fan blade 120 will be described. Based on the description, a person of ordinary skill in the art will know how to implement the concepts with multiple fan blades 120.
As shown in
The arrangement of the components as shown in
As shown in
In the preferred embodiment, each fan blade 120 can rotate approximately 180 degrees, through a plane perpendicular to the central axis A, from a fully stowed position in the fan housing 138 to a fully deployed position with the fan blade 120 extended away from the housing 138. A gear arrangement is employed for this purpose. The rotary drive plate 126 is mounted on the fan plate 124 in a manner that permits the rotary drive plate 126 to pivot about the central axis A, relative to the rotating fan plate 124. A sector gear 140 is mounted to the rotary drive plate 126 at its periphery. At a proximal end 142 of the fan blade 120 is a driving spur gear 144. The driving spur gear 144 is attached to the proximal end 142 of the fan blade such that rotation of the driving spur gear 144 causes rotation of the fan blade 120 about the blade's pivot axis B. Therefore, as the driving spur gear 144 rolls along the sector gear 140 in a first direction, the fan blade 120 rotates about its blade pivot axis B in a first rotational direction causing the blade 120 to deploy. As the driving spur gear 144 rolls along the sector gear 140 in a second direction, opposite the first direction, the fan blade 120 rotates about its blade pivot axis B in a second rotational direction, opposite the first rotational direction, causing the fan blade 120 to move towards a stowed configuration.
The method used in the preferred embodiment to translate the sliding block 132 motion into motion of the rotary drive plate 126 (relative to the main rotating fan plate 124) is very important. Special drive slots are provided in the rotary drive plate 126 and the fan plate 124 that engages the sliding block 132 via a drive roller 146.
Referring to
With reference to
For example,
The shape of the rotary plate drive slot 150 in the rotary drive plate 126 is very important for smooth blade deployment. It is desirable for the blades 120 to start deploying slowly, then pick up to a steady speed until near the end of the motion. Critically, at the end of blade deployment the speed should drop to zero so that the mechanism has infinite mechanical advantage in the blade open position. This serves to “lock out” the blades in the fixed open position.
It is important to have the blades 120 accurately positioned in the full open position while the fan is running, or balance will be compromised. Giving the mechanism infinite mechanical advantage in the deployed position also reduces the actuator arm forces to near zero. This prevents unbalanced side loading of the actuator carriage 104 and allows tolerances/slack to be easily taken up.
Another important function of the large rotary drive plate 126 is that it can coordinate the deployment of two (or more) blades 120. Without a means of coordination, the arms can push the slide blocks 132 in an unbalanced manner, creating jerky uneven motion of the deploying fan blades.
Referring back to the rotary plate drive slot 150 of
The same preferred drive slot shape will give a blade speed curve vs. actuator position shown in
The new blade deployment mechanism described above fulfills the “wish list” for a high-end deployable blade ceiling fan. The mechanism is powerful, quiet, and smooth. In the preferred embodiment it uses less than 10 watts of electrical energy to move the blades and has shown greater than 25 years life expectancy in normal service. The structure is compact, allowing for aggressive housing designs and it lends itself to low-cost manufacturing methods. Many of the parts will be made from molded reinforced plastics, for example.
The blades 120 are stowed inside the housing 138 in a “flat” configuration, for minimum use of space. In other words, the plane of each blade surface 121 is substantially perpendicular to the fan center axis A when in the stowed position. In order for the blades 120 to move air when the fan is turning, the blades must be “pitched up” to a predetermined angle relative to the fan center axis A, when in the deployed position. It is important that the blade pitch angle be accurate and repeatable over the life of the fan, or aerodynamic imbalances will occur while the fan is running. It is also important that the blade pitch mechanism be strong and robust, to resist damage from blade impacts or abuse.
In order for a ceiling fan to blow air towards the user effectively, the fan blades should be angled relative to the central axis A. In other words, the fan blade 120 should have a pitch. The fan blade 120 comprises a leading edge 152 and a trailing edge 154. The leading edge 152 leads the fan blade 120 during the rotation and the trailing edge 154 follows the rotation. It is understood that the rotation of the fan blades 120 can be reversed and so the leading edge 152 can become the trailing edge 154 and vice versa. However, for purposes of this discussion, only one direction of rotation will be discussed with the leading edge 152 designating the edge of the fan blade 120 that leads the rotation. With this understanding, when the fan 100 is deployed, the fan blade 120 should have a pitch such that the leading edge 152 is elevated above the trailing edge 154. When the fan 100 is in the stowed configuration, the leading edge 152 and the trailing edge 154 are substantially within the same plane.
In many embodiments, the fan blade 120 is not mounted at its center of mass on the blade tilt shaft 166. Thus some force may be required to push the blade tilt plate 162 and pitch the fan blade to the “up” position where it can move air. In the preferred embodiment, a spring 168 is provided to assist the blade tilt plate 162 movement.
In the preferred embodiment, the blade tilt plate 162 is actuated in the pitch “up” direction as the blade 120 is rotated out to the deployed position. Likewise the blade tilt plate 162 is actuated in the pitch “down” direction (against the spring 168) as the blade 120 is rotated into the stowed position inside the housing 138. Thus the blade 120 will be flat as it enters the housing 138 and will require minimal space.
It is desirable to pitch the blade 120 up slowly as it moves out of the housing 138. This is pleasing to the user and it also spreads the work of moving the blade 120 up over a larger motion of the linear actuator 102. For instance, if the blade 120 was to suddenly pitch up only at the very end of deployment travel, it would require higher force. In addition, experience has shown that spreading the pitch up movement over the whole blade deployment motion is also more accurate and repeatable as it reduces large movements over short distances. It is important to have accurate, repeatable blade pitch angle to ensure balance while the fan is running.
The preferred embodiment utilizes an eccentric cam 170 arrangement on a blade mount plate 172 that interacts with the blade tilt plate 162 to cause the fan blade 120 to pitch up and down. The blade tilt plate 162 has two opposing drive faces 163a, 163b. The drive faces 163a, 163b are curved toward each other and spaced apart sufficiently to allow the eccentric cam 170 to reside in the space between the drive faces 163a, 163b. In between the drive faces 163a, 163b is a hole 165 through which the blade tilt cam 164 can protrude.
The blade mount plate 172 may be rigidly fixed to the fan plate 124. The blade tilt plate 162 is mounted to the blade mount plate 172 such that the eccentric cam 170 engages the drive faces 163a, 163b of the blade tilt plate 162 as the blade tilt plate 162 rotates about the eccentric cam 117. The eccentric cam 170 causes the blade tilt plate 162 to slide linearly, for example, perpendicular to the pitch axis P.
Therefore, as the fan blade 120 moves from a stowed configuration to a deployed configuration, the blade tilt plate 162 rotates about the fan blade pivot axis B, while the blade mount plate 172 remains fixed relative to the fan plate 124. This causes the drive face 163b to engage the eccentric cam 170 and the eccentricity of the cam 170 forces the blade tilt plate 162 to move in a linear direction. Linear movement of the blade tilt plate 162 causes the blade tilt plate 162 to push against blade tilt cam 164 causing the blade tilt cam 164 to rotate about the pivot axis P. Rotation of the blade tilt cam 164 causes the blade tilt shaft 166 to rotate about the pivot axis P, which in turn causes the fan blade 120 to rotate and causes the leading edge 152 to move upwardly higher than the trailing edge 154 (pitched up). A spring 168 is positioned against the blade tilt plate 162 to facilitate this upward movement. In moving back to the stowed configuration, the blade tilt plate 162 rotates about the blade pivot axis B in the opposite direction causing a second drive face 163a to engage the eccentric cam 170. This causes the blade tilt plate 162 to move in the opposite linear direction causing the blade tilt cam 164 to rotate about the pitch axis P in the opposite direction, causing the blade tilt shaft to rotate about the pitch axis P in the opposite direction, which in turn causes the leading edge 152 of the fan blade 120 to lower into the same general plane as the trailing edge 154 (pitch down). This provides a smooth pitch movement of the blade 120 over its entire 180 degree deployment.
In
In the preferred embodiment of the fan invention described herein, the blades 120 are provided with an adjustment for the fully deployed position. This adjustment is necessary to account for manufacturing tolerances. In
As in
Linear actuator 102 is also generally configured with extra travel to allow compression of resilient elements 129. Note that elements are shown as springs in
In the general configuration of the preferred embodiment of fan 100, housing 138 has independent upper and lower sections, with blade assemblies 120 mounted in between. In
In a more advanced configuration of fan 100, screws 186 may be configured with additional length relative to the length of spacers 184. This extra length allows the body of actuator 102 to move along main fan axis A, towards and away from mounting plate 182. Blade assemblies 120 and upper housing 138a are fixed so they cannot translate along main fan axis A. Since lower housing 138b is mounted to the distal end of actuator assembly 102, lower housing 138b may also translate along main fan axis A. This creates several design advantages for fan housing 138. For instance, lower housing 138b can be brought up close to blades 120 when blades 120 are stowed, but can move away for more clearance when blades 120 are deployed and running. In another configuration, lower housing 138b can be raised to completely cover the outside edges of blades 120 when they are in the stowed position. This would allow blades 120 to be totally concealed when not in use. The difference between the installed length of screws 186 and spacers 184 will determine the distance that lower housing 138b moves during operation.
The movable mounting of actuator 102 allows for automatic timing of the movements of blades 120 and lower housing 138b, without the need for additional actuators or controls. Referring to
The automatic timing of the movement of lower housing 138b is similar during blade deployment. With blades 120 in the stowed position, actuator 102 and lower housing 138b is held against gravity in a proximal position relative to blades 120. As deployment of blades 120 starts, carriage 104 moves upward and relaxes the holding force. This allows gravity to translate actuator body 102 and lower housing 138b downward away from the stowed blades 120. Eventually actuator body 102 and lower housing 138b will reach a lower limit of travel defined by the length of screws 186. At this point carriage 104 continues its movement and deployment system 128 is forced to start deploying blades 120. Lower housing 138b at this point is well clear of the moving blades.
In the preferred embodiment of fan 100, a digital control system is provided to coordinate the movement of deployment system 128 with rotation of main fan motor 122. When fan 100 is not in use, it is generally desirable to have blades 120 in a stowed position inside housing 138. When a user commands fan 100 to turn on and operate, it is desirable to first deploy blades 120 and then start turning main fan motor 122. The digital control system inhibits the operation of main fan motor 122 until it has sensed that blades 120 are in a suitable deployed position. Likewise, when the user commands fan 100 to turn off, it is desirable to immediately cut power from main fan motor 122, and wait until fan 100 has slowed down to a suitable low speed before retracting the blades. The digital control system employs a tachometer sensor to inhibit retraction of the blades until fan 100 has slowed to desired speed, or even stopped turning.
The digital control system may also monitor the forces encountered during blade deployment and retraction, to detect one or more blades 120 striking an object or deployment system 128 binding. Likewise, retraction of blades 120 into housing 138 may create a pinching hazard for hands and fingers. The digital control system can be configured to monitor forces in deployment system 128 to detect pinching and immediately reverse the blade retraction.
In the preferred embodiment, actuator 102 is a stepper-type motor. The distance moved by such a stepper actuator may be monitored to adjust for wear in service and ensure full movement of deployment system 128 in both deployment and retraction.
In some embodiments, the basic steps for the control system to start fan 100 from an OFF configuration are: inhibit rotation of main fan motor 122, start actuator 102 in the DEPLOY direction, monitor distance traveled (steps) until blades 120 have deployed sufficiently, monitor force in deployment system 128 to detect blade strike or bind, start main fan motor 122 once blades 120 have deployed sufficiently, stop actuator 102 once blades 120 have fully deployed.
In some embodiments, the basic steps for the control system to stop fan 100 from an ON/RUNNING configuration are: immediately cut power to main fan motor 122, monitor rotational speed of main fan motor 122 via a tachometer sensor, inhibit actuator 102 until main fan motor 122 speed has dropped to a suitable level, start actuator 102 in the RETRACT direction once main fan motor 122 speed is suitably low, monitor distance traveled (steps) until blades 120 have reached the fully stowed position, monitor force in deployment system 128 to detect blade pinch or bind, stop actuator 102 once blades 120 have fully retracted.
The foregoing description of the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention not be limited by this detailed description, but by the claims and the equivalents to the claims appended hereto.
This patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/575,890, entitled “Deployable Fan with Linear Actuator,” filed Oct. 23, 2017, which application is incorporated in its entirety here by this reference.
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