SAME

CROSS-REFERENCE TO RELATED APPLICATION This application claims prio ity of U.S. Provisional

Application No, 62/061,212 _, , filed on October 8, 2014»

The disclosure relates to a gear assembly and a door mount mechanism, m re particularly to a gear assembly including a planetary gear set and a clutch, and a door mount mechanism including the gear assembly.

BACKGROUND

Electronic security systems have been developed for a number of years. Recently, electronic technology has been used in combination with a traditional door lock to provide smart, lock functionality. A disadvantage of such smart look resides in that replacement of an existing lock is inevitable, and the installation process of the new smart lock is relatively complicated arid time—consuming. Moreover, installation of the smart lock also requires a specialized manual labor to use tools for mounting the smart lock and a cor esponding system.

Accordingly, there is a smart lock that may be attached to the existing lock. One Of the key elements of the smart lock is a gear mechanism to be driven by a motor for rotating a thumb knob of the existing look. The gear mechanism should have high efficiency and increased torque capability to save energy. However, the relatively high torque, i.e., the rotational resistance of the irsotcr when the motor is not operating, makes it difficult to turn the smart lock manually.

SUMMAR

Therefore, an object of the disclosure is to provide a gear assembly and a door mount mechanism including the same which enable automatic turning of a thumb turn of a door lock using a motor via the gear assembly while allowing easy manual operation of the door mount mechanism when required.

According to a first, aspect of the disclosure, the gear assem l includes aplanet y gear set nda clutch , The planetary gear set includes a sun gear, at least one planet gear meshing with the sun gear, a carrier supporting said at least one planet gear, and an outer ring gear meshing with said at least one planet gear. The clut h is operable to engage with and disengage f m the planetary gear set to enable the planetary gear set to switch between a first mode and a. second mode.

According to a second aspect of the disclosure, the door mount mechanism is configured for a. smart lock system- The door jsount mechanism is adapted to be mounted onto a door for rotating a. thumb turn of a door lock, which is mounted on the door. The door mount mechanism includes a casing, a rotatable component, an i n t erme d iate cou li g ct ua t i ng un 11. The ca s ing has a door -mounting end that is adapted for abutting against the door, and defining a receiving space that is adapted for receiving the door lock, and that has an opening at the door-mount ing end and adapted for extension of the door lock therethrough. The rotatabie component is coupled rot t bly to the casing. The intermediate coupling is connected co-rotatabiy to the rotatabie component, and is adapted for driving rotation of the thu b turn of the door lock such that the thumb turn is co-rotaLabie with the rotatabie component . The actuating unit is controllable to actuate rotation of the rotatabie component, and includes a motor and a gear assembly. The gear assembl includes a planetary gear set and a clutch. The planetary gear set is driven rotatabiy by the motor, and includes a sun gear, at least one planet gear meshing with the sun gear, a carrier supporting said at least one planet gear, and an outer ring gear meshing with said at least one planet gear. The clutch is operable to engage with and disengage from the planetary gear set to enable the planetary gear set to switch between a first mode and a. second mode.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the disclosure will become apparent i the following detailed description of the embodiments with reference to the accompanying drawings, of which:

Figure 1 is a perspective view of an embodiment of a door mount mechanism according to the disclosure;

Figure 2 is a perspective view of a rotatable component and an actuating unit of the embo iment of the door ou t mechanism;

Figure 3 is another perspective view of the rotatabie component and the actuating unit of the embodiment of the door mount mechanism;

Figure 4 is an exploded perspective vie¾? of an Oldham coupiing

Figure 5 is a schematic view of tongae-and-groove mechanisms in combination with a rotational plate;

Figures 6A and 6B illustrate a bottom view and a top view of a planetary gear set of this embodiment, respectively;

Figures ?.¾ and 7B respectively illustrate a mova le armature of an elec romechanical solenoid engaging with and disengaging front the planetary gear set;

Figures 8A and SB respectively illustrate retraction and extension, of the movable armature of this embodiment according to the disclosure;

Figures 9A and 3B illustrate that a carrier is rotated to prevent friction between the movable armature and an engagement part, during retraction of the movabl armatur ;

Figu es 10A and 1 OB ii lust rat e a first implementation of a sensor of the electromechanical solenoid;

Figures 11A and 11B illustrate a second im lementation of the sensor of the electromechanical solenoid; and

igures 12A and 12B illustr te a third im lementation of the sensor of the elect ro echanical solenoid.

DETAILED DESCRIPTION

As shown in Figures I to 4, an embodiment of a door mount mechanism, e.g., a smart lock, according to the disclosure is adapted for use in a smart lock system, and is adapted to be mounted onto a door (not shown) for rotating a thumb turn (not shown} of a door lock (not shown) . The door lock Includes a base plate (not shown) which is mounted n the door and on which the thumb turn is rotatably disposed. The door mount mechanism includes a casing 1, a rotatabie component 2, an actuating unit 3 and an intermediate coupling 4.

The casing I includes a base wail 11, a surrounding wail 12 extending from a periphery of the base wail 11 and cooperating with the base wail 11 to define a receiving space. In this embodiment, the base wail 11 is substantially square. The surrounding wall 12 has a door-mounting end 121, and the receivin space has an opening at the door-moun ing end 121 and adapted for extension of the door lock therethrough. I this embodiment, the base wall 11 is forced, with a round hole 111.

The rotatabie component 2 is coupled rotatably to the casing 1. The rotatabie component 2 has a base portion 2! engaging rotatably the round hole ill of the casing

1, and a knob portion 22 projecting f om the base portion 21 away from the receiving space and being accessible to a user ,

The actuating unit 3 includes a motor 31 and a gear assembly 32 that includes a planetary gear set 600 (see Figures 6Aand6B) and a clutch. The clutch is exempt i fied as an electromechanical solenoid 800 in this embodiment (see Figures 8A and SB); however, practical implementation of the clutch is not limited to the disclosure herein. The planetary gear set 600 is driven rotatably by the motor 31 or the actuating unit 3 so as to drive rotation of the rotatable component 2. The actuating unit 3 is connected to a control circuit (not shown) . During operation of the smart lock system, the control circuit receives commands from a user device, such as a mobile phone, and the actuating unit 3 is activated by signals received f om the co t ol circuit to operate to drive rotation of the rota table component

2. The control circuit in this embodiment is exemplified as a mic eprocesso .

The door mount meehan issTi is a universal mechanism to accommodate various configurations of existing door lock. The universal mechanism is robust such that it pe mits some range of misalignment between the existing door lock and the door mount mechanism. For example, most door locks are designed to be locked/unlocked by turning t e thumb turn by ninety degrees (clockwise/counterclockwise) , but in reality, the rotational angle required to lock/unlock is not exactly ninety degrees. It may he either more than 90 degrees or less than 90 degrees. Therefore, the door mount mechanism is adaptable for any rotational angle that is not exactly ninety degrees. In another embodiment, the door mount mechanism is adaptable to thumb turn' s asymmetry to a shaft (not shown) and the shaft's eccentricity to the base plate.

The door mount mechanism for the smart lock system is especially suitable for activating the thumb turn of a door lock for use in a house or an apartment . Further, the door mount mechanism can be easily assembled and disassembled by a user. The intermediate coupling 4 is adapted for driving rotation of the thumb turn of the door lock such that the thumb turn is co-rotatabie with the rotatable c mponent 2. The door m unt mechanism uses the intermediate coupling A to increase the fit across various types of thumb turns of door locks available on the market. For ex-ample, the intermediate coupling 4 is one of an Oldham coupling, and tongue-'a nd-grcove mechanisms in combination with a rotational plate. However, other types of the intermediate coupling 4 may be used to- mitigate or correct misalignments, asymmetry and eccent icity, such as rubber, sponge or a robotic finger . The usage of the intermed!ate cou ii g 4 s

increases the tolerance for mi sal ignaient , asymmetry, eccentricity between the existing door lock and the door mount mechanism. The use of the Oldham coupling is illustrated in Figure 4 » The use of the tongue-and-gtoove mechanisms in combination with the rotational plate is illustrated in Figure 5.

Referring to Figures 6A and 53, a bottom view and a top view of the planetary gear set 600 of this embodiment are illustrated respectively. The planetary gear set 600 includes a sun gear 602, at least one planet gear 606, a carrier 604 and an outer ring gear 60S, The sun gear 602 is attached to the motor 31 (see Figure 2), and is driven rota t bly by the motor 31. Three planet gears 606 are given as an example in this embodiment, each of which is of the same size and meshes with the sun gear 602. The carrier 604 supports the planet gears 606 _r and is roiatabis along with revolution of the planet gears 606 around the sun gear 602. The carrier 604 is formed with at least one engagement part €12 for engagement with the electrcmsc anical solenoid S0O (clutch) (see Figure BB: , and three engagement parts 612 are given, as an example in this embodimen . The outer ring gear 608 is formed with inward-facing teeth and mes es with the planet gears 606. The carrier 604 is in connect ion. with the outer ring gear 60S via the planet gears 606, The rotatabie component 2 is formed with gear teeth 610 for meshing with the outer ring gear 60S such that the outer ring gear 608 engages with the rotatable component 2. The electromechanical solenoid 800 is coupled ele trically to the cont ol circuit, is opera l to engage with and disengage from the planetary gear set 600 to enable the planetary gear set 600 to switch between a first mode (e.g., an automatic mode) and a second mode {e.g., a s¾nuai mode),.

A planetary gear set, compared with a parallel axis gear set, has relativel high power density. I additio , the planetary gear set further has advantages of a reduced volume, multiple kinematic combinations , purely torsional reactions, and coaxial shafting. The planetary gear set also includes properties of high bearing loads, constant lubrication requirements, inaccessibility, and design complexity. The efficiency loss in the planetary gear set is about 3% per stage, and such high efficiency ensures that a high percentage of energy being input is transmitted through the planetary gear set, rather than being wasted on mechanical losses inside the planetary gear set. Further, load in the planetary gear set is shared among multiple planet gears such that torque capability of the planetary gear set is increased. In. this w y, the more planet gears are employed in the planetary gear set, the greater the load capability and the higher the torque density. The planetary gear set also provides stability due to an even distribution of mass and 0

increased rotational stiffness. Torque applied radially onto gears of the planetary gear set is transferred radially by the gears, without lateral pressure on gear teeth of the gears.

EM gare 7& is a perspective view illustrating a portion of the retatable component 2, the planetary gear set 600, and a movable armature 802 of the electromechanical solenoid 800 (i.e., the clutch and see Figure 8B) of this embodiment according to the disclosure. The planetary gear set 600 enables high efficiency and increased torque capability to save energy. However, the high torque makes it difficult to manually turn the ro tatable component 2 which is attached to the planetary gea set 600, Accordingly, a controlling clutch switching mechanism (i.e., the electromechanical solenoid 800 as exemplified in this embodiment) is introduced, which when powered, enables the planetary gear set 600 to switch between the automatic mode and the manual mode.

Accordingly, in the automatic mode, the movable armature 802 of the electromechanical solenoid 800 is controlled to engage with one of the engagement parts 612 of the carrier 604 (see Figure SB, ΊΆ and SB) to limit movement of the carrier 60 such that rotation of th sun gea 602 drives the planet gears €06 to spin on respective axes of the planet gears 606 without revolving around the sun gear 602 so as to drive rotation of the outer ring gear 60S. In this way, the movable armature 802 of the electromechanical solenoid 800 (shown in Figure 8B) abuts against one of the engagement parts 612 of the carrier 604 to allow the engagement of the motor 31 with the rotatabie component 2 via the planetary gear set 600 for turning the rotatabie component 2, The motor 31 actuates rotation of the sun gear 602, which the transmits torque to the planet gears 606 , which then transmit the torque to the outer ring gear 608, which finally transmits the torque to the gear teeth 610 of the rotatabie component 2 so as to rotate the thumb turn of the door lock via the intermediate coupling' 4. The high torque capability of the planetary gear set 600 allows the motor 31 to turn the rotatabie component 2 with high efficiency so as to significantly increase battery life of the door mount mechanise.

Moreover, in the automatic mode, when the motor 31 is not operating and is not dr ving rotation of the sun gear €02, rotation of the rotatabie component 2 is hindered by rotational resistance of the motor 31, such that an extra-lock functionality is achieved.

On the other hand, in the manual mode, the movable armature 802 of the electromechanical solenoid 800 s controlled to disengages from the engagement parts 612 of the carrier 604 {see Figures 6B, 7B and 8Ά) to allow movement of the carrier 604 such that the planet gears 606 are spinnable on the respective axes of the planet gears 606 and are revolvable around the sun gear 602 so as to allow tree rotation of the outer ring gear 608. Specifically, the movable armature 802 of the electromechanical solenoid 800 is disengaged from the engagement parts 612 of the carrier 604, and enables the planetary gear set 600 to rotate freely. The motor 31 in combina ion with the sun gear 602 is thus disengaged from the rotatable component 2 due to the f ee movement of the carrier 604, The rotatable component 2 can then be turned manually with ease. The free rotation of the planetary gear set 600 allows manual turning of the rotatable component 2 with almost zero torque without being hindered fay rotational resistance of the motor 31 , The gear teeth 610 formed or. the rotatable component 2 transmit torque via the outer ring gear 608 to the planet gears 606 and the carrier 604 ₁ nd the planet gears 606 may spin on the respective axes of the planet gears 606 and revolve around the sun gear 602 while the sun gear 602 is kept stationary due to the rotational resistance of the motor 31, such that the outer ring gear 608 may rotate freel and the rotatable component 2 may be manually turned with ease. In this way, more battery life is saved while the door mount mechanism is being used in the manual mode.

Refer in to Figures 8A and SB, the electromechanical solenoid 800 of this embodiment of the disclosure is illustrated. The electromechanical solenoid S00 includes the movable armature 802, an I ec romagneticai ly inductive coil 804, an electrically conductive housing 810, a dielectric cover 308 and a spring S06, The movable armst re S02 is exemplified as an iron rod in this embodiment . The eiectromagneticaiiy inductive coil 304 is wound around the movable armature S02, produces an induced magnetic field when provided with an electric current for applying forces to control extension and retraction of the movable armature 802 relative to said electr magnetic<a11y inductive coil 804 {i.e., extension and retraction of the movable armature 802 relative to the electrically conductive housing 810} for engaging with or disengaging from the engagement parts 612 or the carrier 604 (see Figure 6B) . The electrically conductive housing 610 accommodates the electromagnet cally inductive coil 804 therein, is formed with an opening to permit movable extension of the movable rm ture 802 therethrough in o said electrically conductive housing 810, and is made of iron in this embodiment . The dielectric cover 808 covers the opening of the el ct icall conductive housing S1G, and is formed with a hole for the extension and retraction of the movable armature 802 the eth ough.. The dielectric cover 808 accommodates a permanent magnet (not shown) therein for magnetization of the electrically conductive housing 810 and the movable armature S02, The spring $06 has two ends abutting against the dielectric cover 808 and a stopper member 812 fixed onto the movable armatu e 802, respectively.

When a low burst of the electric current is applied to the electrorsagnetically inductive coil 804, an outward force is produced by the induced magnetic field in combination with resilience of the spring 808 so as to extend the movable armature 802, The outward force is greate than the pull force associated with the permanent magnet. When extended, the movable armature 802 contacts the carrier 604. As the carrier 604 rotates , the spring 806 further extends the movable armature 802 which then engages in an optimal position with respect to the planetary gear set 600 {i.e.,, abutting against the engagement parts 612 of the carrier 604) to enable the planetary gear set 600 to operate in the automatic mode. The movable armature 802 may he retracted using another low burst of the electric current which induces the eieotrofr-agneticaiiy inductive coil 804 with an inward force overcoming the resilience of the spring 806, such that the movable armature 802 is locked by the permanent sragnef to enable the planetary gear set 600 to operate in the manual mode.

In addition, to switch the planetary gear set 600 from the automatic mode (see Figure 9A) to the manual mode, the carrier 604 is driven by the motor 31 via the sun gear 602 and the planet gears 606 so as to rotate away from the movable armature 602 of the electromechanical solenoid 800 {see Figure SB} {e.g., in a direc ion oppo ite to the direction, during a previous rotational movement } to prevent friction between the movable armature 802 and the engagement parts 612 during retraction of the movable armature 802.

Moreover, i t is embodiment, the electromechanical solenoid 600 further includes a sensor 900 {see Figures IDA to 12B) which detects the extension and retraction of the movable armature 802,

Referring to Figures I OA and I0B, a first implementation of the sensor 900 of the electromechanical solenoid 800 is illustrated, The electrically conductive housing 810 is grounded, and the dielectric cover SOS provides elec rical insulation between the movable armature 802 and the opening of the electrically conductive housing 810. The sensor 900 includes an electrically conductive member 902 which is disposed on the dielectric cover 8G8 _f which is electrically connected to the movable armature 802 via the spring 806 and the stopper member 812, and which is applied with a voltage, such as a pull-high voltage, 5V.

Referring to Figure 10.%., when the movable armature 802 is retracted and is in electrical contact with a bottom of the electrically conductive housing S10 such that the electrical ly conduct ive member 902 is grounded, via the spring 806, the stopper member 812, the movable arraature 802 and the electrical ly conducti e housing 810, vari ation in voltage of the el ctrical ly conducti e member 902 is measured by a microprocessor so as to determine the retraction of the movable armature 802»

Referring to Figure 1GB, when the movable armature 802 is extended and is not in elect ical coat ct with the bottom of five electrically conductive housing 810, the electrically conductive member §02 is not grounded, such that the electrically conductive member 902 is measured by the microprocessor to maintain at the voltage (i.e., 5V) so as to determine the extension of the movable a mature 802.

In addition, the sensor 900 may further include a sensor plate 904 which i s disposed relati e to the mo able armatu e 802, and which is provided with another voltage , such as 3V. In this way, when the movable armature 802 is extended further to touch the sensor pl te 904, the electrically conductive member 902 is electrically coupled to the sensor plate 90-1 via the spring 806, the stopper member 812 and the movable armature 802, such that variation in voltage of the electrically conductive member 902 (e.g., from 5V to 3V) is measured by the microprocessor so as to determine that the movable armature 802 has reached a desired position to touch the sensor' plate 904.

Referring to Figures ll.A and. 1X8, a second impleme tation of the sensor 900 of the electromechanical solenoid SCO is illus rated. The sensor 900 includes a Wheat stone bridge {not shown) . When the movable armature S02 is retracted or extended such that a length of the spring 806 is changed, the v'deatstone bridge o the sensor 9G0 measures variation in elect ical resistance of the spring SOS so as to determine the retraction and extension of the movable armatu e 802.

Referring to Figures 12A and I2B, a third implementation of the sensor 900 of the electromechanical solenoid 800 is illustrated. The sensor 900 includes a strain gage 906 which has one end attached to the iuovable armature 802, and another end attached to the electrically conductive housing 810. The sensor 900 further includes a Whe stone bridge (not shown) coupled electrically to the strain gage 906. When the movable armature 802 is retracted or extended such that the s rain gage 906 is deformed, the Wheatstone b idge of the sensor 900 measures variation i electrical resistance of the strain gage 906 so as to determine the retraction and extension of the movable armature 802.

To sum u , by m ns of the electromechanical solenoid 800 which is operable to engage with and disengage from the carrier 604 of the planetary gear set 600, the planetary ge r set 600 may be switched between the automatic mode, in which the rotatable component 2 may be driven to rotate by the motor 31, and the manual mode, in which the rotatable component 2 may be manually rotated with ease.

While the disclosure has be n described in connection with what are considered the exemplary embodiments, it is understood that this disclosure is not limited to the disclosed embodiments bat is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications ana equivalent arrangements.