This invention relates to a door lock comprising a lock body fitted with a front plate and a dual-action bolt. The bolt can be moved with reciprocal linear motion between a withdrawn position and a locking position protruding out from the lock body.
An electrically controlled door lock often uses a solenoid or other actuator to control deadbolting means in the lock as to lock the bolt in the deadbolting position. In the deadbolting position, the bolt is out; in other words, protruding out from the lock body. The solenoid is also used to release the deadbolting means from the deadbolting position, which allows the bolt to move into the lock body to the withdrawn position.
In prior art solutions, the solenoid or other actuator is functionally linked to a deadbolting piece that can be moved so that it locks the bolt in the deadbolting position. In a typical implementation, the deadbolting piece is linked to the solenoid shaft, and a spring is used to arrange the shaft to protrude outwards from the solenoid. When the solenoid is de-energised, the spring holds the deadbolting piece in the deadbolting position, and when the solenoid is energised, the solenoid tries to move the deadbolting piece out of the deadbolting position against the spring force.
The spring must be sufficiently strong to hold the locking piece securely in the deadbolting position. This, in turn, means that the solenoid must be sufficiently powerful to be able to move the locking piece against the spring force.
When the door is closed and the lock is in the locked state, seals between the door and the door frame tend to press the lock bolt against the striker plate in the door frame. In case of a dual-action bolt, the bolt also tends to push into the lock body; in other words, it pushes against the deadbolting piece controlled by the solenoid. These external forces counteract the force of the solenoid or other actuator when the solenoid is operated to move the locking piece out of the locking position.
Thus the solenoid or other actuator must be sufficiently powerful to be able to control the deadbolting piece. If the solenoid/actuator is too weak in power, this will cause disruptions in lock operation such as unwanted locked states.
Exit doors are often also equipped with a mechanical actuator such as a bar that must be able to open the door. The bar is called an emergency exit bar. The emergency exit bar is used by pressing it down to release the locked state of the lock. Being an actuator, the bar is also pushed towards the door, particularly in an emergency. This may impose a great force between the striker plate and the bolt. Therefore the force conveyed from the actuator to the lock can be quite great, which may cause the deadbolting parts of the lock to jam and result in unreliable operation.
The objective of the invention is to reduce the electrical energy needed by a lock body to control the lock and, simultaneously, use a lower-power actuator such as a solenoid. It is desired that operation of the lock is reliable also when using mechanical actuators such as an emergency exit bar. The objectives will be achieved as described in the independent claim. The dependent claims describe various embodiments of the lock according to the invention.
The transfer of external force to the locking piece is reduced, which reduces the power requirement for the electric actuator. The impact of external mechanical force on the operation of the locking piece is smaller. The reduction of external force is arranged in two stages of transmission. At the first stage of transmission, the transmitted force is reduced using a wedge part that is in force transmission contact with a lever. The second stage of transmission consists of different leverages at different points of the lever. The lever has a locking surface that can be arranged to contact the locking piece.
In the following, the invention is described in more detail by reference to the enclosed drawings, where
The door lock usually also comprises other control means for controlling the deadbolting means. The lock may have an auxiliary bolt 16 and/or control spindle means 17. The auxiliary bolt prevents the bolt from moving to deadbolting when the door is open but allows it when the door is closed. The control spindle means 17 comprises, for example, a cylinder body, a handle and/or a knob. The connection from the control spindle means and auxiliary bolt to the locking piece 15 within the deadbolting means is simply marked with dashed lines. Thus in the embodiment of
The lock may also be arranged to receive control from an emergency exit bar. In this case very great external forces may be conveyed to the deadbolting means of the lock. This will happen, for example, if the emergency exit bar is simultaneously pushed, imposing great force between the striker plate in the door frame and the lock bolt. This force tends to push the dual-action bolt intensively into the lock body, which may jam the deadbolting means.
The deadbolting means comprise a wedge 10 between the body part 6 of the bolt and the lock body 3. The wedge is arranged to move transversely to the linear path of the bolt. The deadbolting means also comprise a locking piece 15 and a lever 11 comprising a support point 12, a support surface 13 and a locking surface 14. The lever 11 is pivotably supported on the lock body 3 at the support point 12. The support surface 13 is arranged to cooperate with the wedge 10.
The support surface 13 and locking surface 14 can be turned with the lever in relation to the support point 12 between the lever's outward turning position towards the front plate and inward turning position towards the back edge of the lock body.
The locking surface 14 is farther away from the support point 12 than the support surface 13. The lever 11 is spring-loaded towards the outward turning position. The locking piece 15 can be moved against the locking surface 14 to lock the lever and wedge in a deadbolting position, in which deadbolting position the lever 11 is in the outward turning position and the support surface 13 is against the wedge 10, and the wedge is wedged between the bolt body 6 and the lock body 3.
When the deadbolting piece 15 is driven to the open position and the door is being opened, the bolt 4 tends to push inwards under pressure from the striker plate. When using a dual-action bolt, one of the bolt pieces 7 turns in the same direction as the other bolt piece, making the bevelled surfaces of the bolt pieces congruent. The striker plate in the door frame presses against this congruent bevelled surface while simultaneously pushing the bolt into the lock body. It can be seen in
While the wedge slides away from the path of the bolt, the wedge presses the support surface 13 of the lever, and the lever 11 tends to turn in relation to the support point 12. A support counter surface 23 for the support surface of the lever is arranged in the wedge.
The external force that pushes the bolt 4 inwards into the lock body is divided to different components in the wedge and in the lever. The transfer of external force to the locking surface 14 of the lever can be kept minor. The wedge and its connections with the other parts constitute the first stage of transmission at which the external force imposed on the bolt body 6 can be reduced by a factor of 0.6 to 0.8 at the support surface 13 of the lever. The rest of the external force is directed through the second bevelled surface 20 to the lock body 3. The second stage of transmission consists of different leverages at different points of the lever 11. Due to the external force, the lever tends to turn in relation to the support point 12 towards the back part of the lock body. Because the external force component at the support surface 13 of the lever is closer to the support point 12 of the lever than the locking surface 14 of the lever, less force is required at the locking surface to hold the lever 11 in the desired position compared to the force component at the support surface 13. The second stage of transmission reduces the external force by a factor of 0.2 to 0.4 at the locking surface 14. Both stages of transmission combined reduce the external force by a factor of 0.12 to 0.32. The transmission factors depend on the implementation of the embodiment according to the invention.
It can be seen in
At a certain position, when the bolt 4 pushes into the lock body, the wedge 10 moves completely away from the linear path of the bolt, allowing the bolt to move to the withdrawn position without obstruction from the first counter surface 19. At that time the bolt is allowed to move to the withdrawn position illustrated in
Because the stages of transmission substantially reduce the effect of external force on the lever locking surface 14—that is, at the locking piece 15—it is more reliable to drive the locking piece to the desired position compared to a situation in which the external force would affect the locking piece as such. The solenoid or other actuator is not required to be too powerful, which means that the lock body may include a smaller and less expensive solenoid or other actuator. The lock body may also be smaller, making it easy to install the lock in tight quarters. Therefore the electric current required by the solenoid/actuator may also be smaller.
In the present embodiment, the support surface 13 of the lever is a projection, and the support counter surface 23 of the wedge is a cut-out. The support surface is preferably a circular surface. A projection with a circular surface can be conveniently created so that it is a roller attached to the lever 11 in a rotating fashion and its outer surface is said circular surface. The cut-out 23 in the wedge is preferably shaped so that the circular surface 13 is in contact with the wedge regardless of the position of the lever 11. It is certainly also possible that the connection between the lever and wedge is formed in some other way. The rotating roller may be attached to the wedge, and the curved support surface may be in the lever.
It is preferable to locate the lever locking surface 12 at the end of the lever, which provides the maximum length of leverage in relation to the lever support point 12. The locking surface can be, for example, a shear surface. It is preferable that the locking surface is radial to the shaft formed by the support 12.
It is preferable to create the second counter surface 22 in the lock body using a wedge support piece 24. The wedge support piece is attached to the lock body. The second counter surface 22 can also be formed directly in the lock body but the use of a wedge support piece is preferred for ease of manufacture. Depending on other parts of the lock, the wedge support piece can be shaped in different ways.
Even though the lock in the example described above is fitted with a solenoid, it can be replaced with some other actuator such as an electric motor, piezoelectric motor or smart metal actuator. The smart metal actuator can be, for example, a so-called MSM (Magnetically Controlled Shape Memory) device based on a controlled magnetic field. The magnetic field can be controlled electrically. Another option is that a lock according to the invention has no electric actuator at all. An emergency exit bar can be connected to a lock according to the invention. Because the deadbolting means reduce the effect of external force before the locking piece, the lock is reliable even if the force conveyed to the lock due to the operation of the emergency exit bar was great.
As can be noted, an embodiment according to the invention can be achieved through many different solutions. It is thus evident that the invention is not limited to the examples mentioned in this text.
Therefore any inventive embodiment can be implemented within the scope of the inventive idea.
Number | Date | Country | Kind |
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20075295 | Apr 2007 | FI | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FI08/50170 | 4/9/2008 | WO | 00 | 10/26/2009 |