GB2364742A

GB2364742A - Electric strike arrangement

Info

Publication number: GB2364742A
Application number: GB0117194A
Authority: GB
Inventors: Yvind Andreassen
Original assignee: Trioving AS
Current assignee: Trioving AS
Priority date: 2000-07-14
Filing date: 2001-07-13
Publication date: 2002-02-06
Anticipated expiration: 2021-07-13
Also published as: DK176175B1; DE10134551B4; NO20003628L; NO312558B1; NO20003628D0; GB2364742B; SE523433C2; DK200101100A; DE10134551A1; GB0117194D0; SE0102504D0

Abstract

An electric strike comprises a bolt keeper (1) which is pivotal between a locking and an opening position and which may be blocked in locking position by means of a blocking element (2) movable in the direction of the pivot axis of the bolt keeper. The movability of the blocking element (2) is determined by a lever (3), which is supported pivotally about a fixed axis (15). On one side of the pivot axis (15), the lever has a relatively short arm portion with a cam surface (17) for cooperation with a surface portion (16) on the blocking member (2). On the other side of the pivot axis, the lever has a relatively longer arm portion for cooperation with a detent member (4), which is movable out of the detent position with respect to the lever (3) when the solenoid (5) of the strike is made dead.

Description

<Desc/Clms Page number 1> The present invention relates to an arrangement in an electric strike, comprising a bolt keeper which is pivotal about an axis between a locking and opening position and which may be locked in the locking position by means of a blocking element which is lockable in a blocking position through the intervention of a solenoid, and is releasable therefrom when the solenoid becomes dead, where the arrangement further comprises a lever which is supported pivotally about a fixed axis, said lever having on one side of the pivot axis a first arm portion provided with a cam surface or the like for cooperation with a surface portion of the blocking element, and having on the other side of the pivot axis a second arm portion which, through the intervention of the solenoid, may be held in such a position that the cam surface or the like on the first arm portion holds the blocking element in a position which blocks the bolt keeper. Such an arrangement is known from US 5,439,262. In this arrangement, the two portions of the lever. are approximately of the same length and form an angle of about 90 between them. At its free end, the first arm portion has an abutment surface in the form of a roller which cooperates with the free end of a pivotal safety catch serving as a blocking element for the bolt keeper. The second arm portion of the lever forms the armature for an electromagnet and is biased by two opposed springs so as to be held in a middle position when the electromagnet is dead. In this intermediate position, the roller at the free end of the first arm portion is supposed to assume a position which is just about eccentric with respect to the end of the blocking element arm. The longitudinal axis of both the first arm portion and the electromagnet extend transversely of the longitudinal direction of the lock case, necessitating a larger than desirable depth dimension of the strike housing for certain door installations, particularly where the door frame is made of a metal section. Also, the location of the blocking element behind the bolt

keeper contributes in this respect. The function of the lock in an emergency situation where the bolt keeper is subjected to pressure may easily become uncertain, i.a. due to problems in making the two springs acting upon the second arm portion of the lever balance each other in the exact desired position. Furthermore, friction in the pivot point of the lever and in the roller at the end of the second arm portion may prevent the roller from reaching said eccentric position, the result being that the bolting keeper remains blocked.

The purpose of the present invention is to provide an arrangement of the type mentioned in the introductory paragraph, which ascertains that there will be no risk that the door serviced by the strike cannot be opened in an emergency situation, not even in the case where several persons press against the door to escape at the moment the solenoid is made or becomes dead. Concurrently, the strike should have a sufficiently narrow and shallow form that it will fit into relatively narrow metal doorframe sections. This is obtained according to the invention in that the first arm portion is substantially shorter than the second arm portion, in that the second arm portion extends substantially in the same direction as the axis of the solenoid, and in that the second arm portion is held in said position by a detent member which is movable into and out of decent position with respect to the lever by interaction of the solenoid.

Further preferred features of the invention are recited in the dependent claims.

For better understanding of the invention, it will be described more closely with reference to the exemplifying embodiment illustrated in the appended drawings, where: - figure 1 shows a side view of the parts of a strike according to the invention without the enclosing housing,

where the strike is in locking position, - figure 2 shows the parts in figure 1 seen from above, - figure 3 shows a detail of figure 2 at a larger scale, - figure 4 shows a perspective view of the parts of figure 1, - figure 5 shows a cross-section along the lines A-A in figure 1, - figures 6-9 show the same as figures 1, 2, 4 and 5, respectively, but with the solenoid dead, and - figures 10.-13. show a situation corresponding to that of -figures 6-9, but after an opening force has moved the bolt keeper to an opening position. In the arrangement shown in the figures, the strike housing has been omitted for clarity. The arrangement comprises a bolt keeper 1, also called a cradle, which has a support 8 in order to pivotbetween a locking (figure 5) and an opening (figure 13) position. The bolt keeper is held in locking position by means of a blocking element 2, which is movable in a direction parallel to the direction of the pivot axis of the bolt keeper. The blocking element 2 and keeper 1 have cooperating inclined surfaces 13, and 14, respectively, which cause the keeper to be jammed in locking position when the blocking element is in a position as close as possible to the keeper, as is shown in e.g. figure 1. The blocking element 2 is biased towards this position by means of a spring 9 acting between the blocking element and a fixed abutment 11. A lever 3 is supported pivotably about an axis formed by a bolt 15 in a fixed bracket 6. The lever 3 has a first, shorter arm portion, which in the figures lies to the left of the bolt 15 and is provided with a cam surface 17 (figure 3).. To the right of the bolt 15, the lever has a sec-

ond, relatively longer arm portion, which is defined i.a. by an inclined surface 18. The lever is biased in the clockwise direction by means of a spring 10. When the lever 3 assumes the position shown e.g. in figures 2-4, the cam surface 17 will cooperate with a surface portion or recess 16 on the blocking element 12 in such a way that the blocking element will not be able to move towards the right from its blocking position. The lever 3 may be blocked in this position by means of a detent member 4, shown in the form of a pin extending from a detent plate 12. The latter is in turn movable by means of a solenoid 5 between the detent position shown in figure 2, where the solenoid 5 is live, and the releasing position shown in figure 11, where the solenoid is dead so that its core and the plate 12 have been moved towards the right by a spring 7. When the lever 3 is in the blocking position as shown in e.g. figure 2, the moment arm through which the .contact force against the surface portion 16 on the blocking element 2 is acting about the pivot axis 15, is considerably smaller than the corresponding moment arm for the contact force against the pin 4. The relationship between these moment arms may advantageously lie in the area 0.1-0.4. Due to this large ratio, a small force from the pin 4 is sufficient to hold the blocking lever 3 in blocking position. Furthermore; the inclined surface on the blocking lever, which is in contact with the pin 4, has an angle which preferably is larger than the friction angle between the blocking lever and the pin 4. As a result, when the solenoid spring pulls the pin 4 out of decent contact with the lever, the inclined surface 18 on the lever will provide a positive force contribution to this movement. Since both the lever 3 and the pin 4 typically will be made of steel, the angle of the inclined surface 18 should be at least 20 .

The function of the strike according to the invention will be described more closely below.

When the keeper 1 is in the locking position, as shown in figures 1-5, the lever 3 cannot pivot due to the pin 4, and the blocking element 2 will not be able to move towards the right and release the keeper because the surface 16 on the blocking element abuts the immobilized cam surface 17 on the blocking lever. In this position, current is continuously supplied to the solenoid 5.

If it is desired to open the door (not shown) serviced by the strike, the current to the solenoid 5 is cut, whereupon the core of the solenoid and the plate 12 with the pin 4 are pulled towards the right by the spring 7 of the solenoid to the position shown in figures 6-8. If somebody tries to open the door in this situation, the keeper 1 will be pivoted to the position shown in figure 13. As a result, the cooperation between the surfaces 13 and 14 on the blocking element and keeper will push the blocking element 2 towards the right. This is possible since the surface 16 on the blocking element now will be able to push the cam surface 17 on the lever 3 out of the way because the detent pin no longer hinders the necessary pivoting of the lever 3 counterclockwise. once the small protrusion on the blocking element 2 carrying the surface 16 has passed the cam surface 17 on the lever, the spring 10 will bring the lever back to its initial position, as shown e.g. in figure 11.

Next, when the door is closed, the door will bring the bolt keeper 1 from the position shown in figure 13 back to its initial position in figure 9. The spring 9 will now be able to push the blocking element 2 to its blocking position as shown e.g. in figure 7, the lever 3 being permitted to perform the pivoting movement necessary in order for the protrusion with the surface 16 on the blocking element to pass the cam surface 17. When the parts have

resumed the position shown in figure 7, a suitable control system, which the skilled person easily can envision, can cause current once more to be supplied to the solenoid, the result being that the detent plate 12 with the pin 4 moves back to the detent position shown in figures 1-4. It will be understood that the design of the strike according to the invention, with the direction of motion of the solenoid being parallel to the pivot axis of the keeper and motion of the blocking element 2, and the orientation of the lever 3 in the same direction, facilitate making the strike quite narrow both with respect to height and width, in order to permit to installing it in narrow metal sections. Furthermore, the skilled person will understand that the invention is not limited to the exemplifying embodiment disclosed, but may be varied and modified in a number of ways within the scope of the appended claims.

Claims

CLAIMS 1. An electrical strike, comprising a bolt keeper (1) which is pivotal about an axis between a locking and an opening position and which may be blocked in the locking position by means of a blocking element (2), which is lockable in a locking position through the intervention of a solenoid (5) and releasable therefrom when the solenoid becomes dead, further comprising a lever (3) which is supported pivotally about a fixed axis (15), said lever (3) having on one side of the pivot axis (15) a first arm portion with cam means (17) for cooperation with a surface portion (16) on the blocking element (2), and having on the other side of the pivot axis (15) a second arm portion (18) which, through intervention of the solenoid (5), may be kept in such a position that the cam means (17) on the first arm portion holds the blocking element (2) in a position which blocks the bolt keeper (1)@, characterized in that the first arm portion is substantially shorter then the second arm portion; in that the second arm portion extends substantially in the same direction as the axis of the solenoid (5); and in that the second arm portion is held in said position by a detent member (4) which is movable into and out of detent position with respect to the lever (3) through intervention by the solenoid (5).
2. An electrical strike according to claim 1, characterized in that the detent member (4) is arranged on a plate (12) which is movable by means of the solenoid (5).
3. An electrical strike according to claim 1, characterized in that the direction of motion of the solenoid is parallel to the direction of motion of the blocking element.
4. An electrical strike according to one of the

<Desc/Clms Page number 8>

preceding claims, characterized in that the direction of motion of the solenoid (5) is parallel to the pivot axis of the bolt keeper (1).
5. An electrical strike according to one of the preceding claims, characterized in that the bolt keeper is a pivotal cradle (1) equipped with an inclined surface (14) for cooperation with an inclined surface (13) on the blocking element (2).
6. An electrical strike according to claim 5, characterized in that the direction of motion of the blocking element is parallel to the direction of the pivot axis of the bolt keeper (1).
7. An electrical strike according to one of the preceding claims, characterized in that the force acting between the surface portion (16) on the blocking element (2) and the cam means (17) on the lever (3) attempts to pivot the lever to a position where it releases the blocking element (2).
8. An electrical strike according to claim 2, characterized in that the second arm portion has an inclined surface (18) which forms a contact point with the detent member (4) and which in contact with the detent member forms an angle with the direction of motion thereof which is somewhat larger than the angle of friction between the materials meeting in said contact point.
9. An electrical strike according to claim 8, characterized in that said angle is at least 20 .
10. An electrical strike according to one of the preceding claims, characterized in that the ratio between the moment arms of the first and second arm portions lies in the range 0.1 - 1.4.

<Desc/Clms Page number 9>
11. An electric strike constructed and adapted to operate as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

11. An electrical strike constructed and adapted to operate as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

<Desc/Clms Page number 10>

CLAIMS 1. An electric strike, comprising a bolt keeper (1) which is pivotal about an axis between a locking and an opening position and which may be blocked in the locking position by means of a blocking element (2), which is lockable in a locking position through the energisation of a solenoid (5) and releasable therefrom when the solenoid becomes de-energised, further comprising a lever (3) which is supported pivotally about a fixed axis (15), said lever (3) having on one side of the pivot axis (15) a first arm portion with cam means (17) for cooperation with a surface portion (16) on the blocking element (2), and having on the other side of the pivot axis (15) asecond arm portion (18) which, through intervention of the solenoid (5), may be kept in such a position that the cam means (17) on the first arm portion holds the blocking element (2) in a position which blocks the bolt keeper (1), characterized in that the first arm portion is shorter than the second arm portion; in that the second arm portion extends substantially in the same direction as the axis of the solenoid (5); and in that the second arm portion is held in said position by a detent member (4) which is movable into and out of detent position with respect to the lever (3) through intervention by the solenoid (5). 2. An electric strike according to claim 1, characterized in that the detent member (4) is arranged on a plate (12) which is movable by means of the solenoid 3. An electric strike according to claim 1, characterized .in that the direction of motion of the solenoid is parallel to the direction of motion of the blocking element. 4. An electric strike according to one of the

<Desc/Clms Page number 11>

preceding claims, characterized in that the direction of motion of the solenoid (5) is parallel to the pivot axis of the bolt keeper (1). 5. An electric strike according to one of the preceding claims, characterized in that the bolt keeper is a pivotal cradle (1) equipped with an inclined surface (14) for cooperation with an inclined surface (13) on the blocking element (2). 6.. An electric strike according to claim 5, characterized in'that the direction of motion of the blocking element is parallel to the direction of the pivot axis of the bolt keeper (1). 7. An electric strike according to one of the preceding claims, characterized in that the force acting between the surface portion (16) on the blocking ,element (2) and the cam means (17) on the lever (3) attempts to pivot the lever to a position where it releases the blocking element (2). . 8. An electric strike according to .claim 2, characterized in that the. second arm portion has an inclined surface (18) which can contact the detent member (4) and which, when in contact with the detent member, forms an angle with the direction of motion of the detent member which is larger than the angle of friction between the respective materials of the inclined surface and the detent member at the point of said contact. 9. An electric strike according to claim 8, characterized in that said formed angle is-at least 20 . 10. An electric strike according to one of the preceding claims, characterized in that the ratio between the' moment arms of the first and second arm portions lies in the range 0.1 - 0.4.

<Desc/Clms Page number 12>