ELECTRICAL DOOR STRIKE FUNCTIONING UNDER PRESSURE

Description

Field of the invention

[0001] This invention relates to locking mechanisms, more particularly to an electrical door strike which tolerates pressure against the door in which it is mounted.

Background

[0002] The part of a door's open and close mechanism that is positioned in the door frame is called a door strike. This is traditionally shaped as a rigid metal bracket with one or more holes, shaped so that a latch bolt or a dead bolt attached to the door blade can be inserted into them. Since such door strikes do not include any moving parts, the opening mechanism is limited to reside in the door blade itself. This mechanism consists, for example, of a door handle mechanically connected with a latch bolt, or a door knob or a key attached to a bolt.

[0003] Electrical door strikes differ from common door strikes by acting as an electronic opening mechanism for the door to which they are mounted. This mechanism usually consists of a movable, springloaded, metallic flap, also known as a strike keeper, latch keeper or strike keeper, which can be locked (the door strike is locked) or released (the door strike is released) by an electronic locking mechanism. The door blade is locked to the door strike by, for example, a latch bolt attached to the door blade, being trapped behind the strike keeper. If the latch bolt cannot be opened in other ways, the door will be closed as long as the strike keeper remains in the locked state. To open the door, the strike keeper must be released so that the fall can slip past.

[0004] One problem with existing electrical connectors is that they have problems with triggering when the door they belong to is put under pressure. A pressure against the door creates frictional forces in the locking mechanism of the door strike, which causes the latter to wedge and not be released. As a consequence, problems arise with the doors not being open in different situations. This may occur, for example, due to large internal or external air currents, sealing strip effects, panic evacuation, or vent-induced pressure differentials. The latter is a rapidly growing problem today in view of the emergence of energy-efficient houses which, due to their air tight construction, often give rise to large pressure differences.

[0005] Producing a door strike that can be released under pressure is unproblematic if there are no space restrictions. But since the door strike is often needed in door frames where space is limited, there is a advantage during mounting if the door strike is small. Assa Abloy and also Step have some automatic door strikes that release under pressure, but these are large, contain many parts and are expensive. The object of the present invention is to provide a compact and inexpensive electrical door strike which releases under pressure.

[0006] DE 10 2017 202376 B3 and US 4 056 277 A both disclose electrical door strikes that are compact and can operate under pressure.

Summary

[0007] The general embodiment of the invention comprises an electrical door strike which can be manufactured compactly and inexpensively and whose locking mechanism can be released even when the door it is mounted to is put under pressure. The door strike comprises a door strike house, a movable strike keeper which rotates in a movement space about an axis substantially parallel to the longitudinal direction of the door strike and a locking mechanism for the strike keeper. The door strike locking mechanism itself is characterized in that it comprises a barrel in the door strike house, a first movable member, a second rotatable member and a rotational mechanism for rotating the second member.

[0008] The barrel in the door strike house has a central axis which is substantially parallel to the axis of rotation of the strike keeper, and that it has an opening adjacent the movement space of the strike keeper. The first movable member is placed in the barrel near this opening, while the second member is placed further away from the movement space of the strike keeper than the first member, in a position where it intersects the central axis of the barrel. The first member is shaped like a ball with radius r, while the second member is characterized as being rotatable. The axis of rotation of the second member is normally on and intersects the central axis of the barrel in a point a which lies in a distance I from the said opening of the barrel. The second the member is shaped such that it has an extent in the radial direction from its axis of rotation (i.e. along the central axis of the barrel) which varies gradually with its angle of rotation ϑ. The total extent from the point a of the two members, along the central axis of the barrel when they rest against each other, is defined by the variable x. x is smaller or equal to l at a rotation angle ϑ2 and greater than l at a different angle of rotation ϑ1. Consequently, the ball will be forced to stay in a position where it protrudes from the opening of the barrel when the second portion has a rotation equal to ϑ1, while being free to be completely within the barrel at a rotation ϑ2. As a consequence, the strike keeper and thus the door strike are locked in a closed state for a rotation ϑ1, while the strike keeper is open (free to move) at a rotation ϑ2.

Brief description of the figures

[0009] The attached figures are intended to clarify the invention. Equal numbers in different figures indicate the same features of the invention.

Figure 1 shows a principle drawing of the door strike.

Figure 2 shows a principle diagram of the door strike locking mechanism.

Figure 3 shows a principle diagram of an embodiment of the said rotatable member.

Figure 4 shows a principle drawing of an embodiment of the said rotation mechanism, the purpose of which is to control the angle of rotation of the said rotatable member.

Detailed Description of Preferred Embodiments of the Invention

[0010] The invention includes a new type of electrical door strike 1 having an opening mechanism which can be easily released even when under pressure.

[0011] More precisely, the electrical door strike (hereinafter called the door strike) comprises a door strike house 2, a movable strike keeper 3 and a strike keeper locking mechanism 4 which can be easily released even when the strike keeper is under pressure. An example of a door strike is shown in figure 1.

[0012] The movable strike keeper is attached to the door strike house, and is allowed to rotate in a movement space 5 about an axis 6 which is substantially parallel to the longitudinal direction of the door strike 7. The longitudinal direction of the door strike is here defined in relation to the door frame to which the door strike is mounted, and always corresponds to the direction of the side of the frame where the door strike is mounted. The strike keeper lock mechanism itself is embedded in the door strike house and includes a barrel 8, a first movable member 10, a second rotatable member 11, and a rotary mechanism for rotating the second member (an example of a rotation mechanism is shown in Figure 4).

[0013] In its preferred embodiment shown in FIG. 2a and b, the barrel is formed in the door strike house itself, with a central axis 13 running parallel to the axis of rotation of the strike keeper, and with an opening 9 which is adjacent the movement space of the strike keeper. The first movable member 10 is located inside this barrel, close to the said opening, and is shaped like a ball with radius r. The barrel must be shaped so that the center of the ball follows approximately the central axis of the barrel.

[0014] The second rotatable member 11 is positioned so as to cut off the central axis of the barrel at a greater distance from the movement space of the strike keeper than the extent of the first movable member. The second member may be positioned inside or outside the barrel itself, but must be positioned so that it can come into direct contact with the first member.

[0015] More precisely, the second member is positioned so that its axis of rotation 16 is at a right angle to and crosses the central axis 13 of the barrel, at the same time as the member 11 itself intercepts the central axis of the barrel. The intersection between the two axes is defined as point a and lies at a distance l from the said opening, as shown in FIG. 2b. For practical and geometric reasons, the axis of rotation of the second member will preferably also be at a right angle to the plane of the door blade.

[0016] The second member has a radial extent 19 from its axis of rotation which varies gradually with its angle of rotation θ. Because this member is positioned such that its axis of rotation crosses othogonally the central axis of the barrel, so its extent along the central axis of the barrel will also vary gradually with θ.

[0017] As the two members can rest against each other, the total extent x of the two members from the point a, along the central axis of the barrel when they rest against each other, varies with. The angle of rotation ϑ can therefore determine the position of the first member along the central axis of the barrel.

[0018] In its preferred embodiment, the second member is shaped such that x is smaller or equal to I at an angle of rotation ϑ 1 (Fig. 2a), and greater than l at a second angle of rotation ϑ2 (Fig. 2b). A rotation angle ϑ2 will cause the strike keeper to move freely and the door strike is in the open position, while a rotation angle ϑ1 will cause the strike keeper, and consequently the door strike, to be locked.

[0019] The locking mechanism is closed and opened by controlling the rotation angle ϑ, and according to the said description can be in two states:

i. The ball is inside the barrel without protruding from said opening. The strike keeper can now move freely and the door strike / door is open (see Fig. 2b, ϑ2).

ii. Less than half of the bullet protrudes from said opening. The strike keeper movement is prevented by the ball and the door strike / door is locked (see Fig. 2a, ϑ1).

[0020] In closed state, the movement of the strike keeper is blocked by the ball protruding into the movement space of the strike keeper. The contact point itself between the strike keeper and the ball will be on the outermost half of the ball so that subsequent orthogonal force 24 between the two will have a component along the central axis of the barrel. The fact that this component will be smaller than the force (from the door) on the strike keeper itself causes the force directed towards the locking mechanism itself to be reduced in relation to other locking mechanisms for electrical door strikes.

[0021] In order to open the door strike, the second member is rotated from an angle til ϑ1 to an angle ϑ2, making it fit inside the barrel for the ball to be pushed into it. Any pressure on the strike keeper will mainly help push the ball into this barrel instead of providing large amounts of unwanted friction in the locking mechanism.

[0022] The force of the strike keeper against the ball surface will also help to provide a rotation of the ball itself in which the lock is opened. Therefore, since the ball rests against the rotatable portion, it is desirable that the direction of rotation required by the second member is oppositely directed than the direction in which the ball rotates upon opening. In this way, the pressure (from the strike keeper on to the ball) helps to reduce the force required to open the lock.

[0023] Furthermore, both the inward pressure against the rotatable member and the rotational force on the ball are affected by how far out in the strike keeper's movement space the ball is in the locking position. Experience has shown that a functioning balance of these variables will be that between 2/3 and 4/5 of the radius of the ball protrudes into the movement space of the strike keeper. The edge of the strike keeper that go against the ball should be rounded with a convex surface with a radius between 1/4 and 1/10 of the radius of the ball.

[0024] It is important that the ball does not protrude too far out of the barrel, as this will cause the lock to wedge permanently. This will happen if the ball protrudes a length close to r or more out of the barrel, as the force of the strike keeper on the ball parallel to the barrel in these cases will be equal to or close to zero. It is desireable to keep the friction between the ball and the barrel as low as possible such that the friction force between the two always are less than the component along the central axis of the barrel of the orthogonal force 24 between the two. If the friction force is bigger the door will not open.

[0025] In order to prevent the ball from protruding too far out of the barrel, either the barrel can be formed with a constriction 28 against the movement space of the strike keeper or the strike keeper can be arranged so that it constantly blocks for members of the barrel's mentioned opening.

[0026] In order to prevent the lock from being shaken open or shut, it is important that the ball and the second rotatable member experience some resistance when moving from one position to another. In this context, the design of the rotatable member is important. (For example, this can be done by designing the surface of the rotatable member so that the ball can rest on this surface rather than wanting to slide over it).

[0027] In one embodiment of the invention shown in fig. 3, the rotatable member comprises a spherical recess 28 with radius r facing the first movable portion at an angle of rotation ϑ2. The rotable member may in this embodiment have a cylindrical half 29 with radius r and a cylindrical side sector 30 on either side of the recess with radius r / 2. In the same embodiment, the cylindrical half has a flat sector 31 which spans 1 to 5 degrees adjacent to a side sector (30) at the angle of rotation ϑ1.

[0028] Locking mechanisms for door strikes will in many applications be opened and closed countless times a day and must therefore be able to withstand wear without the functionality of the locking mechanism failing. The wear itself will mainly pass on the points subjected to strong forces, and in the mentioned invention this is typically at the point of contact between the ball and the barrel, the strike keeper and the ball, as well as between the ball and the rotatable member. In order to reduce the wear at the above-mentioned points, in one embodiment of the invention, the barrel will be shaped as a cylinder with a radius of the order of 5% greater than r. Pressure from the ball towards the barrel will then be distributed on the interior surface.

[0029] In one embodiment of the invention, the angular distance between ϑ1 and ϑ2 is between 60 and 120 degrees, more preferably about 90 degrees.

[0030] In another embodiment of the invention, the rotatable member is shaped such that its extent approximately follows the shape of an arkimedian spiral between the angles ϑ1 and ϑ2. By following this shape, the pressure created against the rotatable member when the locking mechanism is released will be reduced. The power needed to perform the rotation is also reduced, which gives more flexibility in the choice of driving mechanism.

[0031] The rotatable member can be driven, either directly by the driving mechanism, or indirectly via a rotary mechanism. The driving mechanism for the rotation mechanism may, in one embodiment of the invention, consist of a motor, while in another embodiment of the invention it may consist of a solenoid.

[0032] In one embodiment of the invention, the locking mechanism is driven by a solenoid 32, while the rotation mechanism comprises a rotary plate 33, a actuator arm 34 attached to the solenoid, a rotatable release arm 35, a rotation pin 36 and two stoppers 37, 38 attached to the door strike as shown in fig. 4.

[0033] The rotary plate 33 is directly or indirectly rotationally locked to an end 39 of the rotatable member and shaped with two rounded teeth 40 having a U-shaped recess 41 therebetween, as well as a first 42 and a second 43 sector stop.

[0034] The rotatable release arm is shaped to include a rotation hole 44, a sector stopper 45, a head 47 adapted to the U-shaped recess of the rotary plate, and a carrier opening 46. The carrier opening is adapted to be significantly larger than the pin 49 attached to the solenoid actuator arm 34 so that the solenoid moves a distance before it activates the trigger arm. This is because a solenoid is usually weak at the start of its movement. The release arm 35 is attached to the door strike house via a rotary pin adapted to the rotating hole of the release arm.

[0035] The rotation of both the rotary plate and the release arm is limited by the two stops attached to the door strike house. The rotary plate stop 37 is adapted to the two sector stoppers of the rotary plate, while the trigger arm stop 38 is adapted to the sector stop of the trigger arm.

[0036] The rotation of the release arm at the locked position of the strike keeper is limited to a position 48 where the tangent of the contact points between the rotary plate and the release arm is perpendicular to the axis between the point of contact and the axis of rotation of the trigger arm, and where the tangent approximately passes through the axis of rotation of the second rotable member. In this state, the rotational forces applied to the second rotatable member when the strike keeper is shaken or attempted to be opened will be stopped by the trigger arm and passed through the rotary pin and the door strike without causing rotation and subsequent opening of the strike keeper. At the same time, it is possible, by a slight force applied by the solenoid, to open the strike keeper by turning the release arm.

Claims

1. Electrical door strike (1) having a locking mechanism (4) operating under pressure, comprising:

a door strike house (2),

a movable strike keeper (3) which rotates in a movement space (5) about an axis (6) substantially parallel to the longitudinal direction (7) of the door strike,

a strike keeper locking mechanism, comprising:

a barrel (8) in the door strike house with a central axis (13) and with an opening (9) adjacent the movement space (5) of the strike keeper;

a first movable member (10), shaped like a ball with radius r, located inside the barrel near the said opening (9);

a second rotatable member (11) positioned so as to cut off the central axis of the barrel, with a rotational axis (16) substantially orthogonal to and crossing the central axis (13) of the barrel at a point a at a distance l from the said opening of the barrel, and extending a distance (19) in a radial direction from its axis of rotation which varies gradually with its angle of rotation ϑ, so that the total extent x of the two members, from point α, along the central axis of the barrel, when resting against each other, is smaller or equal to l at an angle of rotation ϑ2 (open strike keeper) and greater than l at another rotation angle ϑ1 (locked strike keeper), and

a rotation mechanism for rotating the second member, characterized in that the central axis (13) of the barrel is substantially parallel to the axis of rotation of the strike keeper.

2. Electrical door strike according to claim 1, wherein the barrel is formed with a constriction (27) against the movement space of the strike keeper so that the first movable member cannot fall completely out of the said opening.

3. Electrical door strike according to claim 1, wherein the strike keeper constantly blocks members of the said opening such that the first movable member cannot completely fall out of this opening.

4. Electrical door strike according to any one of the preceding claims, wherein the second member comprises:

a spherical recess (28) with radius r facing the first movable member at an angle of rotation ϑ1,

a cylindrical half (29) with radius r, a cylindrical side sector (30) on either side of the recess with radius r/2.

5. Electrical door strike according to claim 4, wherein the cylindrical half has a flat sector (31) which spans 1 to 5 degrees at an angle of rotation ϑ 2 adjacent to a side sector (30).

6. Electrical door strike according to claim 1, wherein the barrel is shaped like a cylinder having a radius of the order of 5% greater than r.

7. Electrical door strike according to claim 1, wherein the radial extent of the second member follows approximately an arkimedian spiral between the angles ϑ1 and ϑ2.

8. Electrical door strike according to claim 1, wherein the rotation mechanism is driven by a motor.

9. Electrical door strike according to claim 1, wherein the angular difference between ϑ1 and ϑ2 is between 60 and 120 degrees, more preferably about 90 degrees.

10. Electrical door strike according to claim 1, wherein the rotation mechanism is driven by a solenoid.

11. Electrical door strike according to claims 1 and 10, wherein the rotation mechanism comprises:

a rotary plate (33), directly or indirectly rotationally locked to one end of the second member, the rotation plate comprising two rounded teeth (40) with a U-shaped recess (41) therebetween, and a first (42) and a second (43 ) sector stop,

a actuator arm (34) attached to a solenoid (32),

a rotatable release arm (35) comprising a rotation hole (44), a sector stopper (45), a head (47) adapted to the U-shaped recess (41) of the rotation plate, and a carrier opening (46) adapted to be substantially larger than the pin ( 49) attached to the solenoid carrier arm,

a rotary pin attached to the door strike adapted to the rotation hole,

a stopper attached to the door strike, adapted to the two sector stoppers of the rotation plate,

and a stopper attached to the door strike such that the rotation of the release arm at the locked position of the strike keeper is limited to a position where the tangent of the contact points between the rotary plate and the release arm is perpendicular (48) to the axis between the point of contact and the axis of rotation of the release arm, and the tangent approximately passes through the axis of rotation to the second rotable member.

Ansprüche

1. Elektrischer unter Druck arbeitender Türöffner (1) mit einem Verriegelungsmechanismus (4), der umfasst:

ein Türöffnergehäuse (2)

ein bewegliches Öffneraufschraubstück (3), das sich rin einem Bewegungsraum (5) um eine Achse (6) dreht, die im Wesentlichen parallel zu der Längsrichtung (7) des Türöffners verläuft,

einen Öffneraufschraubstück-Verriegelungsmechanismus, der umfasst:

einen Zylinder (8) in dem Türöffnergehäuse mit einer Mittelachse (13) und mit einer Öffnung (9), die an den Bewegungsraum (5) des Öffneraufschraubstücks angrenzt;

ein erstes bewegliches Element (10), das wie eine Kugel mit einem Radius r ausgebildet ist, das sich im Inneren des Zylinders nahe der Öffnung (9) befindet;

ein zweites drehbares Element (11), das so positioniert ist, dass es die Mittelachse des Zylinders absperrt, mit einer Drehachse (16), die im Wesentlichen orthogonal zu der Mittelachse (13) des Zylinders verläuft und diese an einem Punkt α in einem Abstand/von der Öffnung des Zylinders kreuzt, und sich um einen Abstand (19) in einer radialen Richtung von seiner Drehachse erstreckt, der schrittweise mit seinem Drehwinkel ϑ variiert, so dass sich die Gesamterstreckung x der zwei Elemente von einem Punkt α entlang der Mittelachse des Zylinders, wenn sie aneinander anliegen, kleiner gleich l in einem Drehwinkel ϑ2 (offenes Öffneraufschraubstück) ist und in einem anderen Drehwinkel ϑ1 (verriegeltes Öffneraufschraubstück) größer als l ist, und

einen Drehmechanismus zum Drehen des zweiten Elements, dadurch gekennzeichnet, dass die Mittelachse (13) des Zylinders im Wesentlichen parallel zu der Drehachse des Öffneraufschraubstücks verläuft.

2. Elektrischer Türöffner nach Anspruch 1, wobei der Zylinder mit einer Verengung (27) gegen den Bewegungsraum des Öffneraufschraubstücks ausgebildet ist, so dass das erste bewegliche Element nicht vollständig aus der Öffnung fallen kann.

3. Elektrischer Türöffner nach Anspruch 1, wobei das Öffneraufschraubstück Elemente der Öffnung konstant blockiert, so dass das erste bewegliche Element nicht vollständig aus dieser Öffnung fallen kann.

4. Elektrischer Türöffner nach einem der vorstehenden Ansprüche, wobei das zweite Element umfasst:

eine kugelförmige Aussparung (28) mit einem Radius r, der dem ersten beweglichen Element in einem Drehwinkel ϑ1 zugewandt ist,

eine zylindrische Hälfte (29) mit einem Radius r, einem zylindrischen Seitensektor (30) auf jeder Seite der Aussparung mit einem Radius r / 2.

5. Elektrischer Türöffner nach Anspruch 4, wobei die zylindrische Hälfte einen flachen Sektor (31) aufweist, der 1 bis 5 Grad in einem Drehwinkel ϑ2 an den Seitensektor (30) angrenzend überspannt.

6. Elektrischer Türöffner nach Anspruch 1, wobei der Zylinder wie ein Zylinder mit einem Radius in der Größenordnung von 5 % größer als r ausgeformt ist.

7. Elektrischer Türöffner nach Anspruch 1, wobei die radiale Erstreckung des zweiten Elements in etwa einer archimedischen Spirale zwischen den Winkeln ϑ1 und ϑ2 folgt.

8. Elektrischer Türöffner nach Anspruch 1, wobei der Drehmechanismus durch einen Motor angetrieben wird.

9. Elektrischer Türöffner nach Anspruch 1, wobei der Winkelunterschied zwischen ϑ1 und ϑ2 zwischen 60 und 120 Grad beträgt, stärker bevorzugt ungefähr 90 Grad.

10. Elektrischer Türöffner nach Anspruch 1, wobei der Drehmechanismus durch eine Magnetspule angetrieben wird.

11. Elektrischer Türöffner nach den Ansprüchen 1 und 10, wobei der Drehmechanismus umfasst:

eine Drehplatte (33), die an einem Ende des zweiten Elements direkt oder indirekt drehverriegelt ist, wobei die Drehplatte zwei abgerundete Zähne (40) mit einer U-förmigen Aussparung (41) dazwischen und einen ersten (42) und einen zweiten (43) Sektoranschlag umfasst,

einen Betätigungsarm (34), der an einer Magnetspule (32) angebracht ist,

einen drehbaren Freigabearm (35), der ein Drehloch (44), einen Sektorstopper (45), einen Kopf (47), der an die U-förmige Aussparung (41) der Drehplatte angepasst ist, und eine Trägeröffnung (46), die so ausgelegt ist, dass sie im Wesentlichen größer als der Stift (49) ist, der an dem Magnetspulenträgerarm angebracht ist,

einen Drehstift, der an dem Türöffner angebracht und an das Drehloch angepasst ist,

einen Stopper, der an dem Türöffner angebracht und an die beiden Sektorstopper der Drehplatte angepasst ist,

und einen Stopper, der an dem Türöffner angebracht ist, so dass die Drehung des Freigabearms in der verriegelten Position des Öffneraufschraubstücks auf eine Position begrenzt ist, wobei die Tangente der Kontaktpunkte zwischen der Drehplatte und dem Freigabearm normal (48) zu der Achse zwischen der Kontaktstelle und der Drehachse des Freigabearms verläuft, und die Tangente in etwa durch die Drehachse zu dem zweiten Drehelement verläuft.

Revendications

1. Gâche électrique (1) présentant un mécanisme de verrouillage (4) fonctionnant sous pression, comprenant :

un logement de la gâche (2),

une gâche mobile (3) qui tourne dans un espace de mouvement (5) autour d'un axe (6) sensiblement parallèle à la direction longitudinale (7) de la gâche, un mécanisme de verrouillage de la gâche, comprenant :

un barillet (8) dans le logement de la gâche avec un axe central (13) et avec une ouverture (9) adjacente à l'espace de mouvement (5) de la gâche ;

un premier élément mobile (10), en forme de boule de rayon r, situé à l'intérieur du barillet à proximité de ladite ouverture (9) ;

un second élément rotatif (11) positionné de manière à couper l'axe central du barillet, avec un axe de rotation (16) sensiblement orthogonal et traversant l'axe central (13) du barillet en un point α à une distance I de ladite ouverture du barillet, et s'étendant sur une distance (19) dans une direction radiale à partir de son axe de rotation qui varie progressivement avec son angle de rotation ϑ, de sorte que l'étendue totale x des deux éléments, à partir du point α, le long de l'axe central du barillet, lorsqu'ils reposent l'un contre l'autre, est inférieur ou égal à I à un angle de rotation ϑ2 (gâche ouverte) et supérieur à I à un autre angle de rotation ϑ1 (gâche verrouillée), et

un mécanisme de rotation pour faire tourner le second élément, caractérisé en ce que l'axe central (13) du barillet est sensiblement parallèle à l'axe de rotation de la gâche.

2. Gâche électrique selon la revendication 1, dans laquelle le barillet est formé avec un étranglement (27) contre l'espace de mouvement de la gâche de sorte que le premier élément mobile ne puisse pas tomber complètement hors de ladite ouverture.

3. Gâche électrique selon la revendication 1, dans laquelle la gâche bloque constamment les éléments de ladite ouverture de telle sorte que le premier élément mobile ne puisse pas tomber complètement hors de cette ouverture.

4. Gâche électrique selon une quelconque des revendications précédentes, dans laquelle le second élément comprend :

un évidement sphérique (28) de rayon r faisant face au premier élément mobile selon un angle de rotation ϑ1,

une moitié cylindrique (29) de rayon r , un secteur latéral cylindrique (30) dans les côtés de l'évidement de rayon r/2 .

5. Gâche électrique selon la revendication 4, dans laquelle la moitié cylindrique présente un secteur plat (31) qui s'étend de 1 à 5 degrés selon un angle de rotation ϑ2 adjacent à un secteur latéral (30).

6. Gâche électrique selon la revendication 1, dans laquelle le barillet a la forme d'un cylindre présentant un rayon de l'ordre de 5 % supérieur à r.

7. Gâche électrique selon la revendication 1, dans laquelle l'étendue radiale du second élément suit approximativement une spirale arkimédienne entre les angles ϑ1 et ϑ2.

8. Gâche électrique selon la revendication 1, dans laquelle le mécanisme de rotation est entraîné par un moteur.

9. Gâche électrique selon la revendication 1, dans laquelle la différence angulaire entre ϑ1 et ϑ2 est comprise entre 60 et 120 degrés, plus préférablement d'environ 90 degrés.

10. Gâche électrique selon la revendication 1, dans laquelle le mécanisme de rotation est entraîné par un solénoïde.

11. Gâche électrique selon les revendications 1 et 10, dans laquelle le mécanisme de rotation comprend :

une plaque rotative (33), directement ou indirectement verrouillée en rotation sur une extrémité du second élément, la plaque rotative comprenant deux dents arrondies (40) avec un évidement en forme de U (41) entre elles, et une première (42) et un second (43) arrêt de secteur,

un bras d'actionnement (34) fixé à un solénoïde (32),

un bras de déverrouillage rotatif (35) comprenant un trou de rotation (44), une butée de secteur (45), une tête (47) adaptée à l'évidement en forme de U (41) de la plaque rotative, et une ouverture de support (46) adaptée pour être sensiblement plus grand que la broche (49) fixée au bras support de solénoïde,

une broche rotative fixée à la gâche adaptée au trou de rotation, une butée fixée à la gâche, adaptée aux deux butées sectorielles de la plaque rotative,

et une butée fixée à la gâche de telle sorte que la rotation du bras de déverrouillage à la position verrouillée du gâche est limitée à une position dans laquelle la tangente des points de contact entre la plaque rotative et le bras de déverrouillage est perpendiculaire (48) à l'axe entre le point de contact et l'axe de rotation du bras de déverrouillage, et la tangente passe approximativement par l'axe de rotation jusqu'au second élément rotatif.

Drawing