Abstract:
This invention provides a locking device for coffee brewing apparatus of an automatic coffee maker. With this invention, when the top cover is closed, the brewing chamber can be locked and sealed at the same time automatically, while after coffee is brewed, the brewing chamber can be unlocked automatically, which provides easy operation that is convenient for users.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims priority from CN Patent Application No. 200520062845.X filed on Aug. 15, 2005, entitled “Locking Device for Coffee Brewing Apparatus”, which is incorporated herein by reference for all purposes. 
   TECHNICAL FIELD 
   The present invention relates to a coffee maker, and in particular, to a locking device for a coffee brewing apparatus of a coffee maker. In accordance with the present invention, the brewing chamber of the coffee maker is locked automatically when the top cover of the coffee maker is closed so as to form a sealed coffee brewing chamber. Moreover, after the coffee is brewed, the sealed brewing chamber is unlocked automatically when the top cover is opened. The present invention is applicable to both an espresso coffee maker and a drip coffee maker. 
   BACKGROUND OF THE INVENTION 
   An espresso coffee maker or a drip coffee maker includes a top cover, a coffee maker body and a brewing chamber assembly. The brewing chamber assembly comprises: a brewing chamber cover fixed at the bottom of the top cover, a brewing chamber body fixed in the coffee maker body, a brewing chamber seat installed in the coffee maker body around the brewing chamber body, and a sealing ring installed between the brewing chamber cover and brewing chamber seat. Normally, the sealed brewing chamber is formed manually by the following steps: the first step is to close the top cover, and the second step is to rotate the brewing chamber seat about the vertical central axis of the brewing chamber body manually with the handle of the brewing chamber seat, so as to make the brewing chamber seat and the brewing chamber cover rotate relative to each other and become sealed. With the prior method, closing the top cover and forming the sealed brewing chamber had to be implemented in separate steps, the brewing chamber cover had to be aligned with the brewing chamber seat when rotating, and a relatively large force had to be applied due to the sealing ring provided in the brewing chamber seat. Accordingly, users found them inconvenient to operate. 
   An object of the present invention is to overcome the shortcomings of the prior art by providing a locking device for a coffee brewing apparatus of an automatic coffee maker, which automatically locks the coffee brewing chamber as the top cover is closed on the coffee maker body. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention relates to an automatic coffee maker comprising a top cover, a coffee maker body, a pivot axis and a control circuit. The top cover is connected on the top of the coffee maker body via the pivot axis, whereby the top cover may be rotated about the pivot axis, enabling the opening and closing of the coffee maker. With the aid of the locking device for the coffee brewing apparatus, the brewing chamber of the coffee maker can be locked automatically, so as to form a sealed brewing chamber, at the same time as the top cover is closed. 
   The locking device for the coffee brewing apparatus comprises:
         a brewing chamber cover fixed at a bottom of the top cover, with at least one locking pin installed at a periphery of the brewing chamber cover;   a brewing chamber body fixed in the coffee maker body;   a brewing chamber seat in the coffee maker body disposed around the brewing chamber body rotatable around a vertical central axis of the brewing chamber body;   at least one latching member engageable with the at least one locking pin extending inwardly at a periphery of the brewing chamber seat, whereby, when the brewing chamber seat is rotated around the vertical central axis, the locking device assumes one of an unlocked position and a locked position, wherein, in the unlocked position, the brewing chamber cover is rotatable about the pivot axis away from the brewing chamber seat, and in the locked position, the brewing chamber seat is locked in the vertical direction with the brewing chamber cover, and the brewing chamber cover is not rotatable about the pivot axis away from the brewing chamber seat;   a motor installed in the coffee maker body controlled by the control circuit;   a motion transmission mechanism disposed between the brewing chamber seat and the motor to enable the motor to drive the brewing chamber seat to rotate around the vertical central axis between the unlocked position and the locked position;   a first sensor for detecting when the locking device is in the unlocked position and a second sensor for detecting when the locking device is in the locked position, which are both connected to the control circuit;   wherein, when coffee is to be brewed, the top cover is closed on the coffee maker body and the motor is started by pressing down a start button, whereby under the control of the control circuit, the brewing chamber seat is driven via the motion transmission mechanism to rotate about the vertical central axis towards the locked position; when the brewing chamber seat arrives at the locked position, the second sensor is triggered, and the motor is stopped under the control of the control circuit, thereby locking the brewing chamber cover with the brewing chamber seat, so as to form a sealed brewing chamber; and   wherein after coffee is brewed, the motor is re-started under the control of the control circuit, and the brewing chamber seat is driven via the motion transmission mechanism to rotate about the vertical central axis towards the unlocked position; when the brewing chamber seat arrives at the unlocked position, the first sensor is triggered, and the motor is stopped under the control of the control circuit, thereby unlocking the brewing chamber cover and enabling the brewing chamber cover to be rotated about the pivot axis away from the brewing chamber seat.       

   A sealing ring may be further installed at the periphery of the brewing chamber cover, so that, when the brewing chamber cover is engaged with the brewing chamber seat, the sealing ring is accommodated at the inner side of the periphery of the brewing chamber seat. 
   The motor may be either a step motor or a synchronous motor. 
   A moveable brewing chamber installation may be further disposed inside the brewing chamber body, so that, different brewing chamber installations for different purposes may be installed and changed based on desires, such as for brewing coffee, for brewing tea, etc. 
   According to the present invention, the brewing chamber can be locked and sealed automatically when the top cover is closed. Moreover, after the coffee is brewed, the brewing chamber can be unlocked automatically when the top cover is opened, which provides easy operation and is convenient for users. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which: 
       FIG. 1  is a schematic view of the locking device for a coffee brewing apparatus in accordance with one embodiment of the present invention, wherein the top cover is opened from the coffee maker body, showing the retarding mechanism for damping the closing motion of the top cover; 
       FIG. 2  is a cross-sectional view of the locking device for a coffee brewing apparatus of  FIG. 1 ; 
       FIG. 3  is a cross-sectional view of the locking device for a coffee brewing apparatus of  FIG. 1 , wherein the top cover is closed on the coffee maker body; 
       FIG. 4A  is a plan view of the brewing chamber seat of the locking device for a coffee brewing apparatus in accordance with one embodiment of the present invention;  FIG. 4B  is a schematic representation illustrating the control circuitry of the present invention; 
       FIG. 5  is a cross-sectional view of  FIG. 4  taken along F-X 2 ; and 
       FIG. 6  is a cross-sectional view of  FIG. 4  taken along F-F. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   As illustrated in  FIGS. 1 ,  2  and  3 , according to one embodiment of the present invention, an automatic coffee maker comprises a coffee maker body  23 , a top cover  10 , a pivot axis and a control circuit  25 . The top cover  10  is connected on the top of the coffee maker body  23  via the pivot axis, whereby the top cover  10  is rotatable about the pivot axis, enabling the opening and closing of the coffee maker. 
   A locking device for a coffee brewing apparatus comprises a brewing chamber cover  19 , a brewing chamber body  17 , a brewing chamber seat  7 , a synchronous motor  4 , a motion transmission mechanism, a first sensor  21  for detecting when the locking device is in an unlocked position, and a second sensor  22  for detecting when the locking device is in a locked position. 
   The brewing chamber cover  19  is fixed at the bottom of the top cover  10 . A sealing ring  14  is installed at the periphery of the brewing chamber cover  19 , so that, when the brewing chamber cover  19  is engaged with the brewing chamber seat  7 , the sealing ring  14  is accommodated at the inner side of the periphery of the brewing chamber seat  7 . At the periphery of the brewing chamber cover  19 , outside the sealing ring  14 , several locking pins  11  are installed at an equal distance span, e.g. three locking pins  11  may be provided, each spaced 120° apart. The locking pins  11  may be formed integrally with the brewing chamber cover  19 . 
   The brewing chamber body  17  is fixed in the coffee maker body  23  under the top cover  10 . A moveable brewing chamber installation  16  may be further disposed inside the brewing chamber body  17 , so that, different brewing chamber installations for different purposes may be installed and changed based on desires, such as for brewing coffee, for brewing tea, etc. 
   The brewing chamber seat  7  is installed in the coffee maker body  23  around the brewing chamber body  17 . The brewing chamber seat  7  is rotatable around the vertical central axis  24  (see  FIG. 2 ). Three latches 2 engageable with the three locking pins  11  are installed inwardly at the periphery of the brewing chamber seat  7 , whereby, when the brewing chamber seat  7  is rotated around the vertical central axis  24 , the locking device may assume one of an unlocked position and a locked position. In the locked position, the brewing chamber seat  7  is locked with the brewing chamber cover  19  in the vertical direction, and the brewing chamber cover  19  can not be rotated about the pivot axis away from the brewing chamber seat  7 . The latches  2  may be formed integrally with the brewing chamber seat  7 . 
   As shown in  FIGS. 4A ,  4 B,  5  and  6 , the synchronous motor  4  is installed in the coffee maker body  23  and controlled by the control circuit  25 . Alternatively, the synchronous motor  4  can be replaced by a step motor. 
   The motion transmission mechanism includes a pinion  5  and a driven gear  3 . The driven gear  3  is fixed at the periphery of the brewing chamber seat  7 , and may be formed integrally therewith. The driven gear  3  extends within an angular span, e.g. up to about 22.5°. 
   Both the first and second sensors  21  and  22  can use a micro switch, and both of the first and second sensors  21 ,  22  are connected with the control circuit. As shown in  FIGS. 4A and 4B , the second sensor  22  and the first sensor  21  are installed at the right and left side of the driven gear  3 , respectively. When the driven gear  3  is rotated to the right and arrives at the locked position, it touches the second sensor  22 , whereby the second sensor  22  sends a locked signal to the control circuit  25 . When the driven gear  3  is rotated to the left and arrives at the unlocked position, it touches the first sensor  21 , whereby the first sensor  21  sends an unlocked signal to the control circuit  25 . 
   When coffee is to be brewed, the top cover  10  is closed on the coffee maker body  23 , and under the control of the control circuit  25 , the synchronous motor  4  is started by pressing down the start button  20 . The pinion  5  is rotated, driving the driven gear  3 , which drives the brewing chamber seat  7  to rotate about the vertical central axis  24  clockwise for approximately 22.5°. When the brewing chamber seat  7  arrives at the locked position, the second sensor  22  is triggered, and the synchronous motor  4  is stopped under the control of the control circuit  25 . As a result, the brewing chamber cover  19  is locked with the brewing chamber seat  7 ,  50  as to form a sealed brewing chamber. At this time, water in a reservoir (Tank) is pumped by a pump into a boiler to be heated, boiled water of 2.5-10 BAR is produced and enters into the sealed brewing chamber through a three way connector (T-Valve) and the water distribution installation (Water Dispenser), so as to brew coffee or tea. Details of the water loop of the coffee maker is described in the U.S. patent application filed on May 11, 2004 by the present Applicant, which is entitled “A Multi-Function Coffee Maker and Use Thereof” under the publication No. U.S. 2004/0244599. After coffee is brewed, the synchronous motor  4  is re-started under the control of the control circuit  25 , whereby the pinion  5  is rotated, driving the driven gear  3 , and the brewing chamber seat  7  is driven to rotate about the vertical central axis  24  anti-clockwise for 22.5°. When the brewing chamber seat  7  arrives at the unlocked position, the first sensor  21  is triggered, and the synchronous motor  4  is stopped under the control of the control circuit  25 . As a result, the brewing chamber cover  19  is unlocked and can be rotated about the pivot axis away from the brewing chamber seat  7 . 
   As shown in  FIGS. 1 ,  2  and  3 , an open button  15  for the top cover  10 , and a retarding mechanism including damper  8  and damping gear  9  are installed on the coffee maker body  23 . After coffee is brewed, the top cover  10  is opened steadily by pressing down the open button  15 , with the aid of the damper  8  and damping gear  9 , so as to be convenient for changing the coffee, the tea or the moveable brewing chamber installation  16  inside the brewing chamber body  17 .