Patent Publication Number: US-8981899-B2

Title: Electromechanical lock

Description:
FIELD 
     The invention relates to an electromechanical lock and its operation method. 
     BACKGROUND 
     Various types of electromechanical locks are replacing the traditional mechanical locks. Electromechanical locks require an external supply of electric power, a battery inside the lock, a battery inside the key, or means for generating electric power within the lock making the lock user-powered. Further refinement is needed for making the electromechanical locks to consume as little electric power as possible. 
     BRIEF DESCRIPTION 
     The invention is defined in the independent claims. 
    
    
     
       LIST OF DRAWINGS 
       Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which 
         FIG. 1A  illustrates an embodiment of a key; 
         FIGS. 1B and 1C  illustrate various positions of the key; 
         FIGS. 2A ,  2 B and  2 C illustrate an embodiment of a key follower and its positions; 
         FIG. 3A  illustrates an embodiment of a user-powered electromechanical lock and  FIGS. 3B ,  3 C,  3 D,  3 E,  3 F,  3 G,  3 H,  3 I and  3 J illustrate its operations; 
         FIGS. 4A and 4B  illustrate timing and order of the operations in the electromechanical lock; 
         FIGS. 5A ,  5 B,  5 C,  5 D,  5 E and  5 F illustrate an embodiment of an electronic control and mechanical reset of the locking mechanism; 
         FIGS. 6A ,  6 B and  6 C illustrate an embodiment of a battery-powered electromechanical lock where a linearly moving actuator is used; 
         FIGS. 7A ,  7 B,  7 C and  7 D illustrate an embodiment of a battery-powered electromechanical lock where a rotating actuator is used; 
         FIGS. 8A ,  8 B,  8 C and  8 D illustrate an embodiment of an electronic control and mechanical reset of a battery-powered electromechanical lock; and 
         FIG. 9  illustrates a method for operating an electromechanical lock. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following embodiments are exemplary. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several places, this does not necessarily mean that each such reference is made to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. 
     With reference to  FIG. 3A , the structure of an electromechanical lock  300  is explained. The lock  300  comprises an electronic circuit  326  configured to read data from an external source, and match the data against a predetermined criterion. The electronic circuit  326  may be implemented as one or more integrated circuits, such as application-specific integrated circuits ASIC. Other embodiments are also feasible, such as a circuit built of separate logic components, or a processor with its software. A hybrid of these different embodiments is also feasible. When selecting the method of implementation, a person skilled in the art will consider the requirements set for the power consumption of the device, production costs, and production volumes, for example. 
     The external source may be an electronic circuit configured to store the data. The electronic circuit may be an iButton® (www.ibutton.com) of Maxim Integrated Products, for example; such an electronic circuit may be read with 1-Wire® protocol. The electronic circuit may be placed in a key, for example, but it may be positioned also in another suitable device or object. The only requirement is that the electronic circuit  326  of the lock  300  may read the data from the external electronic circuit. The data transfer from the external electronic circuit to the electronic circuit  326  of the lock  300  may be performed with any suitable wired or wireless communication technique. In user-powered locks, produced energy amount may limit the techniques used. Magnetic stripe technology or smart card technology may also be used as the external source. Wireless technologies may include RFID technology, or mobile phone technology, for example. The external source may be a transponder, an RF tag, or any other suitable electronic circuit type capable of storing the data. 
     The data read from the external source is used for authentication by matching the data against the predetermined criterion. The authentication may be performed with SHA-1 (Secure Hash Algorithm) function, designed by the National Security Agency (NSA). In SHA-1, a condensed digital representation (known as a message digest) is computed from a given input data sequence (known as the message). The message digest is to a high degree of probability unique for the message. SHA-1 is called “secure” because, for a given algorithm, it is computationally infeasible to find a message that corresponds to a given message digest, or to find two different messages that produce the same message digest. Any change to a message will, with a very high probability, result in a different message digest. If security needs to be increased, other hash functions (SHA-224, SHA-256, SHA-384 and SHA-512) in the SHA family, each with longer digests, collectively known as SHA-2 may be used. Naturally, any suitable authentication technique may be used to authenticate the data read from the external source. The selection of the authentication technique depends on the desired security level of the lock  300  and possibly also on the permitted consumption of electricity for the authentication (especially in user-powered electromechanical locks). 
     The lock  300  also comprises a support  342  configured to move by electric power to a fulcrum position provided that the data matches the predetermined criterion, i.e. provided that the data is authenticated. The support  342  may be configured to be reset from the fulcrum position with mechanical power when the key is removed from the lock  300 . The mechanical power may be provided by a spring  344 , for example. The lock  300  may be configured so that the key is removable from the lock  300  only in a position where the key is insertable in the lock. An example of this is explained below in connection with  FIGS. 1B and 1C . 
     The lock  300  also comprises a locking pin  318  configured to hold the lock  300 , when engaged, in a locked state, and, when disengaged, in a mechanically openable state. The locking pin  318  may be configured to be engaged with mechanical power when the key is removed from the lock. The mechanical power may be provided by a spring  322 , for example. This is explained below in connection with  FIG. 3J . 
     The lock  300  also comprises a lever  320  coupled with the locking pin  318  configured to receive mechanical power, and to output the mechanical power to mechanically disengage the locking pin  318  provided that the support  342  is in the fulcrum position. 
     The lock  300  may comprise a driving pin  316  coupled with the lever  320  configured to input the mechanical power to the lever  320 . The lever  320  may be configured to receive the mechanical power from insertion of a key. As illustrated in  FIG. 3A , the lever  320  may be a third-class lever: the fulcrum is at the left-hand end of the lever  320 , the mechanical power is inputted into the middle of the lever  320 , and the mechanical power is outputted from the right-hand end of the lever  320 . 
     A coupling  321  between the lever  320  and the locking pin  318  may act as another fulcrum, and the locking pin  318  remains stationary in a locked position provided that the data does not match the predetermined criterion, i.e. provided that the support  342  is not moved to the fulcrum position. 
     The lock  300  may comprise a lock cylinder  120 . The locking pin  318  may be configured to implement the locked state so that, when engaged, the locking pin  318  holds the lock cylinder  120  stationary, and implement the mechanically openable state so that, when disengaged, the locking pin  318  releases the lock cylinder  120  rotatable by mechanical power. In the third-class lever the input effort is higher than the output load, but the input effort moves through a shorter distance than the load, i.e. with such lever  320  the locking pin  318  may securely hold the lock cylinder  120  in place in the locked state as the locking pin  318  penetrates deep enough into the wall of the lock cylinder  120 . A cavity  310  may be formed in the lock cylinder  120  for the locking pin  318 . 
     These embodiments, as well as the cooperation of the support  342 , lever  320  and locking pin  318 , will be explained in greater detail later. 
     The electromechanical lock  300  of  FIG. 3A  is user-powered, i.e. the user generates all the mechanical and electrical power needed for operating the lock  300 . The lock  300  may comprise an electric generator  330  configured to generate electric power from mechanical power. The electric generator  330  may be a permanent magnet generator, for example. The output power of the electric generator  330  may depend on rotating speed, terminal resistance and terminal voltage of the electronic and the constants of the electric generator  330 . The generator constants are set when the electric generator  330  is selected. The electric generator  330  may be implemented by a Faulhaber motor 0816N008S, which is used as a generator, for example. The term electric generator refers to any generator/motor capable of generating electric power from mechanical power. 
       FIG. 3A  illustrates a solution where only one electric generator  330  is used to generate the electric power and feed the electric power to the electronic circuit  326 , and thereupon move the support  342  (to the fulcrum position) with the (generated) electric power. In such a solution, the electric generator  330  is also used as an actuator of the lock; the actuator may put the lock  300  in a mechanically openable state under the control of the electronic circuit  326 . The support  342  may be coupled with a shaft of the electric generator  330 . The shaft may be a moving shaft; a rotating shaft, for example. 
       FIG. 3A  illustrates many other possible components of the lock  300 . The lock  300  may further comprise keyways  122 ,  306 , an electric contact  302 , a key follower  200 , an arm  314 , a spring  324 , a threshold device  332 , a clutch  334 , a main wheel  338 , a stopper  340 , a position switch  328 , and a clutch opener  336 . Furthermore, the lock may be coupled to bolt mechanism  312 . The electric generator  330  may rotate through the main wheel  338  when the threshold device  332  is moving, provided that the clutch  334  is closed. 
     With reference to  FIGS. 1A ,  1 B and  1 C, a key  100  and its positions in the lock  300  are explained. 
     In  FIG. 1A , the key  100  comprises a key grip  101  and a key body  102  (in the form of a bar, for example). The key  100  may also comprise key electronics  106  connected to a sliding contact  108  and the key body  102 . The key electronics  106  may comprise an electronic circuit for storing the data (read by the electronic circuit  326  of the lock  300 ). The key body  102  may comprise different shapes: a rotating position shape  104 , a first shape  118 , a gap  114 , a second shape  110 , and a third shape  116 . The key body  102  may also have axial guides for better positioning control. 
     In  FIG. 1B , the key  100  is shown in a zero position. In the zero position the key  100  may be inserted in or withdrawn from the lock  300  through the keyway shape  122 . 
     In  FIG. 1C , the key  100  is rotated off the zero position. While in the off-zero position, the key body  102  and the keyway shape  122  of the lock prevent removal of the key  100 . 
     Next, with reference to  FIGS. 2A ,  2 B and  2 C a key follower  200  and its positions within the electromechanical lock are explained. The key follower  200  is described in greater detail in another simultaneously filed application: EP 07112676.7. 
     As illustrated in  FIG. 2A , the key follower  200  comprises a first claw  202 , a second claw  204  and a swing lever  206 . The key follower  200  rotates around a shaft  208 . 
       FIG. 2B  illustrates the positions and functions of the key follower  200  when the key  100  is inserted into the lock  300 : 
       FIGS. 3B and 3C  will further illustrate reception of mechanical power with the first shape  118  of the key  100 ; 
       FIG. 3D  will further illustrate the operation allowed by the gap  114  of the key; 
       FIGS. 3E and 3F  will further illustrate the operation of the actuator with the second shape  110  of the key  100 ; and 
       FIGS. 3G ,  3 H and  3 I will further illustrate the operation after the position switch  328  is activated by the second shape  110  of the key. 
       FIG. 2C  illustrates the positions and functions of the key follower  200  when the key  100  is withdrawn from the lock  300 : the key follower  200  may be returned to the gap position by a spring, whereby the position switch  328  is deactivated and the actuator is reset, and after that the third shape  116  of the key  100  may return the key follower  200  to its home position.  FIG. 3J  will further illustrate these operations. 
       FIG. 3B  illustrates the lock status when the first shape  118  of the key  100  is inserted against the first claw  202  in the lock  300 . The key electronics  106  may be connected to the electronic circuit  326  so that one electrical connection is made between the electric contact  302  and the slide contact  108 , and the other electrical connection between the key body  102  and the lock frame  300 . 
     In  FIG. 3C , the key  100  is inserted to a threshold position in the lock  300 : the first shape  118  of the key  100  is still in contact with the first claw  202 . The threshold device  332  is armed by the swing lever  206 . When the key  100  is inserted deeper into the lock, the threshold device  332  is launched and it returns to the home position by a spring. Electric power is produced by the electric generator  330  to the electronic circuit  326  when the threshold device  332  is moving. The threshold device  332  is illustrated in more detail in another patent application by the applicant: EP 05 112 272.9. 
     In  FIG. 3D , the key  100  continues to move into the lock  300 . The key follower  200  is not moving because the second claw  204  is in the gap  114  of the key  100 : delay is made for the electric power generation and the communication. After a sufficient voltage level is reached, the electronic circuit  326  starts, communicates with the key electronics  106  through the electric contacts  302 ,  108 , and authenticates the key  100 . 
     In  FIG. 3E , the second claw  204  is pushed forward by the second shape  110  of the key. The actuator operation is enabled by opening the clutch  334  with the swing lever  206  and the clutch opener  336 . The clutch  334  is described in greater detail in another simultaneously filed application: EP 07112677.5. 
     In  FIG. 3F , the actuator enabling operation is started before the power generation phase is ended, i.e. the key  100  may be inserted too fast into the lock  300 . In such a case, the actuator operation is disabled, because the clutch  334  may only be opened when it is returned to the home position against to the stopper  340 . The lock  300  cannot be opened. 
     In  FIGS. 5A and 5B , the clutch  334  is closed and rotation of the main wheel  338  is blocked by the shapes  504 ,  506 . The main wheel  338  is not rotatable by the electric generator  330 , and the support  342  is not set under the lever  320 . The locking pin  318  is kept in closed position, even though the driving pin  316  is pushed down by the user of the key  100 . 
     In  FIG. 3G , the clutch  334  is opened and the position switch  328  is activated by the second claw  204  and the end of the second shape  110  of the key. The electronic circuit  326  controls the generator  330  as an electric motor when the position switch  328  is activated as follows: the generator  330  is driven in the open direction as illustrated in  FIGS. 5E and 5F , if the key  100  is authenticated, and kept in the closed position as illustrated in  FIGS. 5C and 5D , if the key  100  is not authenticated. 
     In  FIG. 3H , the main wheel  338  is kept in the closed position. The support  342  is not under the lever  320 . The arm  314 , the driving pin  316  and the lever  320  are pushed down by the first shape  118  of the key, but the locking pin  318  is kept in the closed position by the spring  322  and the lock  300  cannot be opened. As shown, the lever  320  misses the support  342  (and hence the fulcrum), if the key  100  is not authenticated. The mechanics of the lock  300  remain secure against malicious manipulation. 
     In  FIG. 3I , the main wheel  338  is driven to the open position by the electronic circuit  326 . The support  342  is set under the lever  320 . The arm  314  and the driving pin  316  are pushed down by the first shape  118  of the key  100 , and the locking pin  318  is pushed down through the lever  320  by the driving pin  316 . As a result, the lock  300  is in the mechanically openable state, and the bolt mechanism  312  may be moved by rotating the key  100 . When the key  100  is rotated, the lock cylinder  120  provides support for the second claw  204  of the key follower  200  so that it keeps its position during rotation. The key  100  has to be returned to the zero position, as illustrated in  FIG. 1B , before it may be withdrawn from the lock  300 . 
     The opening is also illustrated in  FIGS. 5C and 5D . The clutch  334  is opened and rotation of the main wheel  338  is enabled by the shapes  504 ,  506 . As further illustrated in  FIGS. 5E and 5F , the main wheel  338  is rotated by the electric generator  330  to the stopper  508 , the support  342  is set under the lever  320 , and the locking pin  318  may be opened by the user of the key  100  through the arm  314 , the driving pin  316  and the lever  320 . 
     In  FIG. 3J , withdrawal of the key  100  is in progress. The locking pin  318  is returned to the closed position by the spring  322 . The driving pin  316  and the arm  314  are returned to their initial positions by the spring  324 . The lever  320  is returned to initial position together with the driving pin  316  and the locking pin  318 . The clutch  334  is closed by the spring  344  and the main wheel  338  is reset. The second claw  204  is returned into the gap  114  by the clutch opener  336 . The third shape  116  of the key  100  and the second claw  204  return the key follower  200  to the starting position as illustrated in  FIGS. 3B and 2C , when the key  100  is withdrawn from the lock  300 . 
       FIG. 4A  illustrates the order of the lock functions when the key  100  is inserted into the lock  300  in a specified speed. From the key  100  insertion, linear mechanical power is received. Electric power is generated with a part of the received linear mechanical power. A processor of the lock electronics  326  starts when sufficient voltage is generated and it stops when voltage drops below a sufficient level. The key  100  is authenticated with the generated electric power. The actuator is enabled with the mechanical power. The position switch  328  is activated after the key  100  has been inserted in a required depth. Thereupon, the actuator is controlled with the generated electric power, and the lock mechanism is further operated with the mechanical power. If the insertion speed of the key  100  is so slow that the voltage drops below the sufficient level before the position switch  328  is activated, the actuator  330  is not driven, and the lock  300  remains in the locked state. If the key  100  is inserted too fast, the position switch  328  is activated before the key authentication process is ready, and the lock  300  is kept in the closed state. Finally, rotating mechanical power is received and used to operate the bolt mechanism  312 . 
       FIG. 4B  illustrates the lock functions when the key  100  is withdrawn from the lock  300 . Linear mechanical power is received from the key  100  removal. With the received mechanical power, the lock mechanism is operated, and, after the position switch  328  is deactivated, the actuator is reset. Thereupon, the key follower  200  is turned to the start position with the mechanical power. 
     The electromechanical lock may be user-powered, as illustrated in  FIGS. 3A to 3J , but it may also be battery-powered. In both cases, the minimization of electric power consumption is desirable, in the former case for minimizing the amount of electric power that needs to be generated, and in the latter case for maximizing the duration of the battery. 
       FIG. 6A  illustrates the main components of a battery-powered electromechanical lock. The lock  600  may comprise the lock cylinder  120 , the keyways  122 ,  306 , the electric contact  302 , the arm  314 , the driving pin  316 , the locking pin  318 , the lever  320 , the springs  322 ,  324 , a power source  602 , an electronic circuit  604 , an actuator  606 , and a support  608 . Furthermore, the lock may be coupled to the bolt mechanism  312 . Internal or external battery may be used as the power source  602 . An electromagnetic solenoid or a piezoelectric device may be used as the actuator  606  moving the support  608 . 
     In  FIG. 6A , the key  100  is inserted into the lock  600 . The electronic circuit  604  reads data from the key electronics  106  through the electric contacts  302  and  108 . The electronic circuit  604  detects position of the key  100  when the sliding contact  108  ends, and controls the actuator  606  depending on result of the key  100  validation. 
     In  FIG. 6B , the support  608  is not set under the lever  320  before the key  100  is inserted into the bottom of the lock  600 . Even if the arm  314  and the driving pin  316  push the lever  320  down by the first shape  118  of the key  100 , the locking pin  318  is kept in the closed position by the spring  322 , because the support  608  is not under the lever  320  and hence the lever  320  misses its fulcrum. The lock  600  cannot be opened. 
     In  FIG. 6C , the support  608  is set to the open position by the electronic circuit  604 , i.e. the actuator  606  sets the support  608  under the lever  320 . The mechanical power created by the insertion of the key  100  is received by the arm  314 . The arm  314  pushes down the driving pin  316 , whereby the mechanical power is levered by the lever  320  to the locking pin  318 . The lever  320  ejects the locking pin  318  from the cavity  310  in the lock cylinder  120 . In order to open the lock  600 , the bolt  312  may now be moved by rotating the key  100 . 
       FIG. 7A  illustrates an electromechanical lock  700  powered by a battery  706  through key electronics  708  in a key  704 . The lock  700  may comprise the lock cylinder  120 , the keyways  122 ,  306 , the electric contact  302 , the driving pin  316 , the locking pin  318 , the lever  320 , springs  322 ,  324 ,  718 , an electronic circuit  702 , an electric motor  710  coupled to a gearwheel  714 , a support  720 , an arm  712 , and an arm position sensor  716 . Furthermore, the lock may be coupled to the bolt mechanism  312 . 
     In  FIG. 7A , the key  704  is inserted into the lock  700 . The electronic circuit  702  reads data from the key electronics  708  through the electric contacts  302  and  108 . The electronic circuit  702  waits for the arm position sensor  716  to be activated by the arm  712 .  FIGS. 7A and 8A  illustrate an embodiment of reset mechanism of the gearwheel  714 , the gearwheel  714  is kept in a locked state by the arm  712  and its spring  718 . 
     In  FIGS. 7B and 8B , the key  704  is inserted into the lock  700  so that the arm  712  is turned, the gearwheel  714  is released, the arm position sensor  716  is activated and the electric motor  710  may be controlled on the basis of the key authentication by the electronic circuit  702 . 
     In  FIG. 7C , the support  720  is not set under the lever  320  before the key  704  is inserted into the bottom of the lock  700 . So, even if the arm  712  and the driving pin  316  and the lever  320  are pushed down by the key  704 , the locking pin  318  is kept in the closed position by the spring  322 . The mechanical power is not levered to the locking pin  318 , because the lever  320  misses its fulcrum. The lock  700  cannot be opened, i.e. the locking pin  318  prevents the rotation of the lock cylinder  120 , and hence the operation of the bolt  312 . 
     In  FIGS. 7D and 8C , the support  720  is set to the open position by the electronic circuit  702 . The support  720  is set under the lever  320 , the arm  712  and the driving pin  316  are pushed down by the first shape  118  of the key and the locking pin  318  is pushed down through the lever  320  by the driving pin  316 . The lock  700  is in the mechanically openable state, and the bolt  312  may be moved by rotating the key  704 . 
     In  FIG. 8D , withdrawal of the key  704  is in progress. The spring  718  (illustrated in  FIG. 7A ) returns the arm  712  into a shape  800  of the gearwheel  714  and turns it to the locked position as illustrated in  FIG. 8A . 
     Next, a method for operating an electromechanical lock will be described with reference to  FIG. 9 . Other functions, not described in this application, may also be executed between the operations or within the operations. The method starts in  900 . 
     Normally, in  914 , a locking pin is engaged, and the locking pin holds the lock in a locked state. 
     In  902 , data is read from an external source. 
     In  904 , the data is matched against a predetermined criterion. 
     In  906 , the match of the data against the predetermined criterion is checked. 
     If the data matches the predetermined criterion, a fulcrum is provided in  908 . If the fulcrum is provided, mechanical power is levered with the fulcrum to the locking pin to mechanically disengage the locking pin in  910 . In  916 , the locking pin is disengaged, and the locking pin holds the lock in a mechanically openable state. After that, the lock is mechanically opened in  912 . 
     If the data does not match the predetermined criterion, the lock remains closed, i.e. the locking pin remains engaged, and the locking pin continues to hold the lock in the locked state in  914 . 
     The method ends in  918 . 
     The method may be enhanced with the embodiments of the electromechanical lock described earlier. 
     It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.