Patent Application
20110181060
1. Field of the Invention
This invention relates to strikes for doors, and in particular for electric strikes that are operable and can be changed to operate in fail-safe and fail-secure modes.
2. Description of the Related Art
Door locking mechanisms and security doors to prevent theft or vandalism have evolved over the years from simple doors with heavy duty locks to more sophisticated egress and access control devices. Hardware and systems for limiting and controlling egress and access through doors are generally utilized for theft-prevention or to establish a secured area into which (or from which) entry is limited. For example, retail stores use such secured doors in certain departments (such as, for example, the automotive department) which may not always be manned to prevent thieves from escaping through the door with valuable merchandise. In addition, industrial companies also use such secured exit doors to prevent pilferage of valuable equipment and merchandise.
Electric strikes are a class of door mechanisms that have been developed to control access to buildings or areas. An actuator (e.g. an electrically driven motor or solenoid) is used to move a blocking element to block or release a keeper to either prevent or allow release of a door's latch bolt. This keeps the door latched and in the locked position or allows the door to be opened. Typically, electric strikes have two modes, namely a “fail-secure” mode (where the door is locked with the power removed, i.e. the actuation means must be triggered to allow the door to be opened), and a “fail-safe” mode (where the door is unlocked with the power removed, i.e. the actuation means must be triggered to prevent the door from being opened). Some strikes on the market have only one-mode capability, while others are dual mode allowing the installer to select which mode is desired at the time of installation.
Different dual-mode electric strikes have been developed such as the commercially available GEM model GK-300 and ROFU 2400 series models. Each model has a solenoid mounted on a holder, which is movable within the strike housing. A blocking element is directly attached to the plunger of the solenoid, to block movement of the keeper when the strike is in its locked position. A first screw, reachable from outside the housing, cooperates with a slot or elongated opening in the housing, to define the path along which the holder is movable. The strike can be changed between fail-safe to fail-secure modes by loosening the first screw and moving it to one of the ends in the slot. The first screw can then be tightened to fasten the holder to the housing, i.e. the holder cannot move. First and second holes are arranged on the housing, to alternately align with a second screw, also reachable from outside the housing. At each end position along the holder path of movement one of a threaded third or fourth holes, both arranged on the holder, is aligned with either the first hole or the second hole, and the second screw can be inserted into the appropriate first or second hole and screwed into the visible third or fourth hole. This second screw arrangement helps hold the holder in its selected one of the end positions. The installer can configure the GEM and ROFU strikes in either the fail-safe or fail-secure mode by positioning the screw at one of the ends of the slot, and the second screw helps hold the strike in that mode. A similar arrangement is also reflected in U.S. Pat. No. 6,299,225 to Chang.
U.S. Pat. Nos. 6,874,830 and 7,144,053 to Bashford describe an electric strike having a housing, a keeper pivotally arranged in the housing, and a holder slidably arranged in the housing. The electric strike also includes a blocking element slidably arranged in the holder. The blocking element is configured to selectively prevent a rotation of the keeper and allow the rotation of the keeper. The electric strike also includes a two-position mode selector operable from outside the housing, and the selector is configured to selectively move the holder from a first position to a second position and vice versa. The electric strike also includes an actuator configured to selectively move the blocking element. Specifically, when the holder is in the first position, the blocking member allows the rotation of the keeper when the actuator is energized and prevents the rotation of the keeper when the actuator is not energized, and when the holder is in the second position, the blocking member prevents the rotation of the keeper when the actuator is energized and allows the rotation of the keeper when the actuator is not energized.
U.S. Pat. No. 7,540,542 to Geringer et al. describes an electric strike comprising a housing and a keeper pivotally mounted to the housing. A solenoid is arranged internal to the housing and movable between fail-safe and fail-secure positions. A two position mode control slot comprising two counter-bores is included in the housing and a mode control screw is included in the mode control slot. The screw is capable of being tightened in each of the two counter-bore positions in the control slot. The screw is changeable between the two of the positions without removal of the screw. The solenoid is in the fail-safe position when the screw is in one of the two positions and in the fail-secure position when the screw is in the other of the two positions.
The present invention comprises an improved electric strike to provide efficient, reliable and robust operation. One embodiment of an electric strike according to the present invention comprises a housing, and an actuator mounted to the housing to switch operation of the strike between open and locked modes. In changing the modes the actuator provides lateral motion. A blocking element is also mounted to the housing and cooperates with the actuator. The actuator's lateral motion causes rotational movement in the blocking element to switch between the open and locked modes.
One embodiment of a dual mode electric strike comprises a housing and an actuator mounted to the housing and movable between fail-safe and fail-secure positions. The actuator is also operable to switch between lock and unlock. A keeper is rotationally mounted in the housing and blocked from rotating when in the lock mode, and free to rotate when in the unlocked mode. A first bolt paddle monitors for the presence of a latch bolt and a first switch monitors the location of the keeper.
Another embodiment of a dual mode electric strike comprises a housing and a keeper movably mounted to the housing. A blocking element is rotatably mounted to the housing at a plurality of rotation mounting points with the blocking element rotationally movable between locked and unlocked positions. The blocking element comprises a plurality of blocking surfaces to block movement of the keeper when in a locked rotational position.
Another embodiment of an electric strike according to the present invention comprises a housing and an actuator mounted to the housing to switch operation of the strike between open and locked modes, with the actuator providing lateral motion. A blocking element is mounted to the housing and cooperates with the actuator. The actuator's lateral motion causes movement of the blocking element in a direction different than the actuator lateral motion.
Still another embodiment of an electric strike according to the present invention comprises a housing and a keeper rotationally mounted to the housing. An actuator is mounted to the housing to switch operation of the strike between open and locked modes. A blocking element is mounted to the housing and cooperates with the actuator. The actuator causes movement in the blocking element to switch between open and locked modes, with the blocking element having one or more blocking surfaces to contact and block movement of the keeper when the actuator is in lock mode. At least one of the one or more blocking surfaces have a pre-load movement mechanism to reduce friction with the keeper.
The strikes according to the present invention can comprise many different features as described below. These and other aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings which illustrate by way of example the features of the invention.
a is a partial exploded view of the electric strike in
b is a sectional view of the mode position tray on the housing;
FIG.
The present invention provides an improved dual mode electric strike that can be changed in the field to be operable in both the fail-safe and fail-secure modes. In some embodiments according to the present invention, the mode is changed by a simple manipulation of the internal component of the strike through a window in the housing or cover of the strike. In one embodiment this manipulation comprises sliding a mode position tray between two positions corresponding to the fail-safe and fail secure modes. The tray also comprises an improved arrangement for imparting a mode change on the stop lever or blocking element (“blocking element”) that blocks motion of the keeper to prevent the door from opening. The improved arrangement efficiently moves the position of the blocking element in response to movement of the tray to the other one of the positions, or by the solenoid changing from energized to unenergized, or vice versa. In other embodiment this sliding of the mode position tray can be accomplished by removing a cover of the electric strike and manually sliding the tray or the solenoid on the tray.
Different embodiments according to the present invention can also be arranged to provide heavy duty operation that allows for the keeper to withstand elevated forces. In one embodiment, the blocking element that blocks rotation of the keeper to prevent opening of the door is arranged to move between blocking and unblocking position through rotational movement. That is, the blocking element is such that it can axially pivot or rotate within the electric strike to move between the different modes. In still other embodiments, the blocking element provides two blocking points adjacent to the blocking elements mounting points to the housing. This also allows for the electric strike to withstand elevated forces on the keeper when in the keeper blocking position.
Different embodiments according to the present invention can also comprise additional features to provide for improved operation. Some of these include features that allow for the keeper to open when intended even if the keeper is experiencing a “pre-load” force. In prior electric strikes, this pre-load can result in the keeper not opening when in the open mode. Different electric strikes according to present invention can also comprise adjust plates that can be mounted to the keeper to adjust the size of the strike opening for the lock bolt. In still other embodiments, the electric strike can comprise one or more switches to monitor the location of the various internal moving parts of the strike, to monitor the strikes operation and mode.
The present invention is described herein with reference to certain embodiments, but it is understood that the invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In particular many the internal components of the electric strikes according to the present invention can be arranged in many different ways and different embodiments can comprise different internal components. The fail-safe/fail-secure mode selector can be arranged in many different ways, different blocking elements can be used, different pre-load features can be used, and different switches in different locations can be used.
It is also understood that when an element or component is referred to as being “on”, “connected to” or “coupled to” another element, it can be directly on, connected to or coupled to the other element or intervening elements may also be present. Furthermore, relative terms such as “front”, “back”, “inner”, “outer”, “upper”, “above”, “lower”, “beneath”, and “below”, and similar terms, may be used herein to describe a relationship of one component of element to another. It is understood, however, that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures.
Although the terms first, second, etc. may be used herein to describe various elements or components these elements and components should not be limited by these terms. These terms are only used to distinguish one element or component from another element or component. Thus, a first element or component discussed below could be termed a second element or component without departing from the teachings of the present invention.
Embodiments of the invention are described herein with reference to certain illustrations that are schematic illustrations of idealized embodiments of the invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances are expected. Embodiments of the invention should not be construed as limited to the particular shapes of the elements or components illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of an element or component and are not intended to limit the scope of the invention.
Referring now to
As best shown in
The solenoid 26 is mounted to the tray 22 at the tray tab 20. The elements and operation of solenoids is generally known in the art and is not discussed in detail herein. A plunger 52 (best shown in
With this arrangement, the extension of retraction of the plunger 52 in the solenoid 26 causes rotation of the lever 24 about the sleeve 48. This causes rotation of the lever 24 relative to the tray 22. This arrangement also causes sliding of the lever 24 with the tray 22, as the tray 22 is moved between the fail-safe and fail-secure positions.
In different embodiments according to the present invention, the tray 22 can be held in the fail-safe and fail-secure positions using many different holding mechanisms. Referring now to
In strikes according to the present invention, the blocking element 28 is arranged to cooperate with the mode selector to operate the strike in fail-safe or fail-secure modes. In the embodiment shown, the blocking element 28 is mounted within the housing 12 so that it can rotate within the housing 12. Two retaining pins 68 (best shown in
The blocking element 28 has a blocking element finger 78 that is inserted in the slot 80 in the lever 24. The slot 80 can have many different shapes and sizes and can be arranged in many different ways. In most embodiments the slot has multi-angular sections and in some embodiments it can be V or U-shaped. It is understood, however, that the slot can be many other shapes. The slot 80 cooperates with the finger 78 such that movement of the lever 24 relative to the finger 78 causes the finger 78 to change locations within the slot. The multi-angular sections of the slot 80 cause rotation of the blocking element 28 about the retaining pins 68. For example, when the finger 78 moves from the base of the slot 80 to the end of one of the legs in the slot, the blocking element 28 rotates about the pins 68. This movement of the finger 78 in the slot can be caused be sliding the tray 22 or by rotation of the lever 24 through action of the solenoid 26.
Referring again to
As is apparent from the description above and the accompanying figures, the present invention proves a unique mechanism that transfers the lateral motion caused by extension and retraction of the solenoid plunger 52 and sliding of the tray 22 into rotational motion of the blocking element 28. That is, the unique combination of tray 22, lever 24, solenoid 26 and slot 80 translates the lateral motion of the tray 24 and plunger 52 into rotation motion of the blocking element 28. It accomplishes this in both fail-safe and fail-secure modes.
It is understood that many different mechanisms and arrangements can be used to translate this motion in strikes according to the present invention. Some of these include, but are not limited to, cams, gears, pulleys, etc., and the mechanisms can comprise any combination of the devices described herein. It is also understood that different embodiments need not translate lateral movement to rotation movement, but can translate the lateral movement of the solenoid plunger into many different directions other than in the same direction as the plunder.
The blocking element 28 also provides the advantage of two blocking surfaces 84a, 84b (best shown in
It is understood that the blocking element have only one blocking surface or can have more than two, and can be mounted in or to the housing using many different arrangements. For example, the blocking element can be mounted to the housing using a single pin that runs between the first and second pin holes. Another example can comprise a single mounting point that can either be at the end of the blocking element or at a location off the end, such as near the middle of the blocking element. Those skilled in the art would be aware of other alternative arrangements and these are only a few of the arrangements that can be used in strikes according to the present invention.
The electric strike 10 is described above with reference to changing modes by manipulating the strike's internal components through the mode control access window 18. It is understood, however, that the strike's internal components can be manipulated using many different methods and arrangements. Some embodiments can be provided without an access window and the internal component of the strike can be manipulated after removal of the strike cover. In other embodiments, the strike cover can be partially removed to access the internal components. For example, the strike cover can have a hinge along one of its surface or edges that allow for all or part of the cover to rotate away from the strike about the hinge to reveal the strike's internal components. Once the change is made between fail-safe and fail-secure modes, the cover can be returned to its position on the strike. The cover can then be held in place by tabs or screws. In still other embodiments, levers, knobs, handles, switches, screws, bolts or rivets can be used to manipulate the strikes internal components either through the cover or after removal of the cover.
The present invention also provides other features that allow for efficient operation under different circumstances. In most cases strikes can efficiently and reliably change modes from blocking the keeper to unblocking the keeper. This reliability, however, can be reduced in some strikes when the keeper experiences pre-loading in the form of an opening force being applied to the door and the keeper. This pre-loading can cause an increased friction between the contacting surfaces of the blocking element and keeper. This in turn can result in hang-up of the blocking element on the keeper, which can prevent it from reliably changing to the unblocking position.
To reduce pre-loading hang-up, different embodiments of the strikes according to the present invention can comprise features to allow the blocking element to more easily move to the unblocking position. Referring now to
The blocking element 28 has surfaces that contact the keeper when in the blocking position, and in this embodiment each of the surfaces has a roller 94 mounted at its end by an axel pin 96. The roller 94 contacts the keeper 82 and when the blocking element 28 is moved from the blocking to unblocking position, the roller 94 rolls along the contact surface with the keeper 82. This rolling action allows the blocking element 28 to move to the unblocking position while experiencing reduced friction with the surface of the keeper 82. This in turn allows the blocking element 28 to move positions more easily, even when under pre-load. It is understood that many other elements can be included to reduce friction between the blocking element 28 and the keeper 82. These can include but are not limited to bearings or layers of non-stick materials such as commercially known Teflon. It is also understood that these friction reducing structure and materials can also be included on the keeper or both the blocking element and the keeper.
The strikes according to the present invention can also provide for certain adjustment features to compensate for variances in different door and lock arrangements.
The strikes according to the present invention can also comprise mechanisms to monitor the state of the strike. Referring now to
Referring now to
The strike 10 is described above with reference to mode position tray 22, solenoid lever 24, and solenoid 26 imparting movement on the finger 78, which in turn causes rotation of the blocking element 28. As discussed above, different arrangements can be utilized to impart this movement on the finger 78 and rotation of the blocking element 28.
When the solenoid plunger 151 moves between the retracted and extended positions it laterally moves the solenoid bar 150. This in turn causes the first and second levers to rotate about their respective one of the screws 156. The forked ends 158 of the levers 154, 156 form a slot for the blocking element finger, the rotation of the first and second levers causes the forked ends 158 of the levers 154, 156 to move in opposing directions. For example, if the bar 150 moves in direction of arrow 160, the first lever 152 moves in direction of arrow 162 and the second lever 154 moves in direction of arrow 164. This action causes a change in the shape of the slot formed by the forked ends 158, which in turn causes movement of the blocking element finger. This in turn causes rotation of the blocking element between blocking and unblocking of the keeper depending on whether in the fail-safe or fail-secure mode. This is only one of the many different alternative mechanisms that can impart the desired movement of the finger and rotation of the blocking element.
Although the present invention has been described in detail with reference to certain preferred configurations thereof, other versions are possible. Therefore, the spirit and scope of the invention should not be limited to the versions described above.
This application claims the benefit U.S. Provisional Patent Application Ser. No. 61/228,830 to Geringer et al., entitled “Electric Strike”, and filed on Jul. 27, 2009.
| Number | Date | Country | |
|---|---|---|---|
| 61228830 | Jul 2009 | US |
