Electric lock provided with an opening handle which acts directly on the spring latch

Abstract: The electric lock comprises a spring latch (11), a reloading piston (12) and an element (14) which is guided in said casing parallel to said piston. The spring latch (11) comprises a stem (32) which is guided in said sliding element and has an end provided with engagement means (34) for said sliding element (14) which are suitable to pull the spring latch (11) into the casing (1) during the opening step. Spring means (39) act on said spring latch to keep said sliding element in abutment against a fixed stroke limiter (33) at which said spring latch protrudes from said casing (1). The stem (32) connects to the hub (42) of the handle so that actuation of the handle causes retraction of the spring latch (11) in contrast with the action of said spring means (39).

Description: The present invention relates to an electric lock provided with an opening handle which acts directly on the spring latch. As is known, electric locks are provided with a spring latch and with a reloading piston provided with a tang being guided in a slot of an element which can slide inside the lock casing and can be blocked by means of a ratchet system controlled by an electromagnet. The reloading piston is coupled to the sliding element by means of a spring which remains compressed when the reloading piston, in door closure position, abuts against the doorjamb, whereas the ratchet system keeps the sliding element blocked. When the ratchet system is released by actuating the electromagnet, the spring acts on the sliding element which, in its movement, pulls the spring latch into the casing, allowing to open the door. When one wishes to open an electric lock by means of its handle, one acts on the ratchet system, releasing the sliding element and causing the retraction of the spring latch indirectly by means of the compressed spring of the reloading piston, exactly as occurs with electromagnet-based actuation. The drawbacks of this opening system are excessive noise and the mechanical stresses to which the elements are subjected; these stresses are due to the impact of the sliding element on the spring latch and on the reloading piston at the end of the retraction stroke. Opening is furthermore controlled by the force of the spring, which is often not sufficient to overcome friction especially if the lock is rarely used or is exposed to external factors which tend to jam it. The preamble of claim 1 is known from FR-A-1 484 810 which describes an electric lock comprising a casing provided with a front wall, a spring latch which is guided in an opening of said front wall, said spring latch comprising a stem, spring means which act on said spring latch to bring it into a position in which it protrudes from the front wall, a slider which is slideably guided in said casing parallel to said stem, means for blocking said slider, said means being controlled by an electromagnet between a position for blocking said slider and a position for releasing it, a reloading piston which is slideably guided parallel to said slider in an opening in said front wall, said piston being elastically connected to said slider by means of a spring, said spring being stronger than the spring means of the spring latch, said spring latch being provided with engagement means for said slider, and an element rigidly coupled to said spring latch. The technical aim of the present invention is a general improvement of such a lock, and in particular improvement relating to the manufacturing, versability and reliability of the lock. This aim is achieved with an electric lock as defined in claim 1. Further peculiarities will become apparent from the following description of a preferred embodiment, illustrated only by way of non-limitative example in the accompanying drawings, wherein: the figure is a partially sectional side view of an electric lock according to an embodiment of the invention. With reference to the above figure, the numeral 1 generally designates the lock casing, which comprises a back wall 2 around which a peripheral wall extends; said peripheral wall is composed of an upper wall 3, a lower wall 4, a front wall 5 and a rear wall 6. The numeral 7 designates the closure cover of the casing, which is fixed by means of screws which engage in threaded bushes 9a, 9b, 9c, 9d which are rigidly coupled to the back wall 2. Three openings are formed in the front wall 5, and the bolt 10, the spring latch 11 and the reloading piston 12 protrude outside the casing through said openings. The reloading piston 12 has a cylindrical stem 13, one end of which engages a sliding element 14, hereinafter termed slider. Said slider 14 is constituted by an L-shaped strip which has one portion 15 adjacent to the upper wall 3 and the other portion 16 normal to said wall 3. The end of the stem 13 is guided in a hole of the portion 16 and is provided with a ring 17 which is meant to abut on the portion 16 so as to act as a shoulder. A collar 18 is formed on the stem 13 and acts as rest for an end of a spring 19 which is fitted on the stem 13; the opposite end of said spring 19 abuts against the portion 16 of the slider 14. An elastic connection is thus provided between the piston 12 and the slider 16; by virtue of this connection, the spring 19 keeps the portion 16 in abutment against the ring 17, nonetheless allowing the stem 13 to move with respect to the portion 16 in contrast with the action of the spring 19. The portion 15 of the slider is guided along the wall 3 of the casing by a pin 20 which slides in a slot 21 of the portion 15; the portion 15 is furthermore provided, at the end of the edge adjacent to the back wall 2, with a tooth 22 which slides on the back wall 2. The tooth 22 is suitable to engage a notch 23 formed on the edge of a pawl 24 which is articulated about a pivot 25 which protrudes from the back wall 2. The pawl 24 can oscillate between a position which blocks the slider 14, which occurs when the tooth 22 engages the notch 23 (the position shown in the figure), and a position for the release of the slider 14, which occurs when the pawl 24 is turned by an angle at which the tooth 22 disengages the notch 23 to allow the portion 15 to slide toward the rear wall 6. The pawl 24 is retained in the blocking position by a lever 26 which is pivoted in a rocker-like manner on a pivot 27 and is subjected to the action of an electromagnet 28 installed in the casing 1. The electromagnet 28 is provided with a core 29 which is actuated outward by an internal spring, so that it is in contact with the lower arm 30 of the lever 26. When the electromagnet 28 is not energized, the core 29 acts, by virtue of the internal spring, on the lower arm 30 of the lever 26, so as to make the upper arm 31 oscillate into abutment against the bush 9b in the position for retaining the pawl 24. Vice versa, when the electromagnet 28 is energized, the lever 26 turns in the opposite direction, allowing the pawl 24 to oscillate downward until it abuts against the bush 9b; in this condition, the tooth 22 is disengaged from the notch 23. The spring latch 11 is also provided with a stem 32 which is guided through a plate which is blocked between the back wall 2 and the cover 7 of the casing and constitutes a fixed stroke limiter 33. The end of the stem 32 is slideably guided through the portion 16 of the slider, and a lug 35 is coupled to said end by means of a ring 34; said lug is folded at right angles to the back wall 2 and belongs to a bar which forms an element (36) which is rigidly coupled to the stem 32 and which extends next to the side 15 of the slider 14. A slot 37 is formed in the bar parallel to the portion 15 of the slider 14 and is engaged by the pivot 25, which thus keeps the bar guided. A collar 38 is formed on the stem 32, and an end of a spring 39 rests against it; the spring 39 is fitted on the stem 32, and its opposite end rests against the plate. The spring 39 is less rigid than the spring 19 and keeps the spring latch 11 in a position in which it protrudes from the front wall; this position is defined by the abutment of the lug 35 against the plate with the interposition of the portion 16, which remains clamped between the plate and the lug 35. The end of the bar which is opposite to the lug 35 has a wing 40 which is also folded at right angles to the back wall 2 and on which a lever 41 can act; said lever 41 is radially coupled to the hub 42, to which the handle for manual actuation of the lock is rotationally coupled. The bar 36 is used to operatively connect the lever 41 to the stem 32 of the spring latch. The hub 42 is rotatably supported in circular seats of the back wall 2 and of the cover 7 of the casing, and is provided with a square hole 43 in which the square pivot of the handle engages with a side fit. The hub 42 is provided with two lugs 44, 45 which are arranged diametrically. A strut 46 acts on the lug 44; it is loosely guided in the bush 9c and actuated by a spring 47 which acts between said bush 9c and a shoulder 48 of the strut 46. By virtue of the spring 47, the hub 42 is kept in an angular position defined by the abutment of the lug 45 against the bush 9d; in this position, the lever 41 is disengaged from the wing 40. The operation of the described lock is as follows. In the door closure position, the spring latch 11 is engaged in the related selvage and thus protrudes from the front wall 5. At the same time, the piston 12 abuts against the doorjamb and is arranged inside the casing. Since the electromagnet 28 is not energized, the core 29 pushes the lever 26 so that it abuts against the bush 9b, so as to prevent the oscillation of the pawl 24 and block the sliding of the slider 14. As a consequence of this, during door closure, when the piston 12 retracts into the casing, the stem 13 slides with respect to the portion 16 of the slider and the spring 19 is compressed. If one wishes to open the door by electrical actuation, energization of the electromagnet 28 turns the lever 26, so that the pawl 24 is free to rotate. Due to the compression of the spring 19 which occurred during door closure, the slider 14 acts with the tooth 22 against the edge of the notch 23, forcing the pawl 24, which is no longer blocked by the lever 26, to rotate into the position which allows the slider 14 to slide freely. The sliding of the slider 14 pulls the spring latch 11 by means of the coupling of the portion 16 on the stem 32. Retraction of the spring latch 11 entails the compression of the spring 39, since said spring, as mentioned, is less rigid than the spring 19. If instead one wishes to open the door manually, clockwise rotation of the hub 42 by means of the action of the handle engaged in the square hole 43 makes the lever 41 pull the bar and therewith the stem 32, which is rigidly coupled in the lug 35. The movement of the bar occurs independently of the movement of the slider 14, which remains blocked, since the pawl 24 is kept in blocking position by the lever 26. The pulling of the stem 32 causes the retraction of the spring latch 11 and the compression of the spring 39 against the plate, so that when the action of the handle ends, the spring 39 returns the spring latch to its protruding position. As can be seen, the electric lock according to the invention perfectly achieves the intended aim. In particular it is possible to control the actuation of the spring latch, avoiding snap-acting movements such as those which occur with electric actuation, thus obtaining gentler and less noisy opening. The positive action applied with the handle furthermore allows to compensate for the force applied by the spring 19 during opening, which may not be sufficient due to increases in internal friction. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims: Electric lock comprising: a casing (1) provided with a front wall (5); a spring latch (11) which is guided in an opening of said front wall (5), said spring latch (11) comprising a stem (32); spring means (39) which act on said spring latch (11) to bring it into a position in which it protrudes from the front wall (5); a slider (14) which is slideably guided in said casing (1) parallel to said stem (32); means (22-26) for blocking said slider (14), said means being controlled by an electromagnet (28) between a position for blocking said slider (14) and a position for releasing it; a reloading piston (12) which is slideably guided parallel to said slider (14) in an opening in said front wall (5), said piston being elastically connected to said slider (14) by means of a spring (19), so as to allow the retraction of said piston (12) into the casing (1) when said blocking means (22-26) is in the position for blocking the slider (14), said retraction of the piston (12), which occurs when it abuts against the door jamb, compressing said spring (19) between the piston (12) and the slider (14); said spring (19) being stronger than the spring means (39) of the spring latch (11); said spring latch (11) being provided with engagement means (34) for said slider (14) which are adapted to allow said slider (14) to pull the spring latch (11) into the casing (1) when said means (22-26) release the slider (14) thereby permitting it to slide due to the compression of said spring (19) between the piston (12) and the slider (14), said engagement between the spring latch (11) and the slider (14) also being such that the spring latch (11) can be retracted into the casing (1) even when the slider (14) is in the blocked position; an element (36) being rigidly coupled to said spring latch (11); characterized in that the stem (32) is guided in said slider (14); said spring means (39), which act on the spring latch (11), tends to keep said slider (14) in abutment against a fixed stroke limiter (33) in the form of a plate which is blocked between the back wall (2) and the cover (7) of the casing (1), said spring latch (11) protruding from said front wall (5) when said slider (14) abuts said fixed stroke limiter (33); a hub (42) which is rotatably supported in said casing (1) and is provided with a hole (43) for the rotary engagement of an actuation handle; said rigidly coupled element being coupled to the stem (32) and operatively connects said stem to the hub (42) of the handle so that actuation of the handle causes movement of said element (36) and retraction of spring latch (11) in opposition to the action of said spring means (39). Electric lock according to claim 1, characterized in that said slider (14) is L-shaped with a first portion (15) which is guided parallel to the sliding direction of the piston (12) and a second portion (16) which is at right angles to said direction; said stem (32) being guided through the fixed stroke limiter (33); said second portion (16) being slideably arranged on said stem (32) between said fixed stroke limiter (33) and a lug (35) of a bar which constitutes said rigidly coupled element (36), said bar being guided parallel to said spring latch (11), and said lug (35) of said element (36) being rigidly coupled to the end of stem (32). Electric lock according to claim 2, characterized in that said hub (42) has a radial arm (41) which acts on a wing (40) of said bar in the direction for the retraction of the spring latch (11). Electric lock according to one of claims 1 to 3, characterized in that said spring means are constituted by a spring (39) which is fitted on said stem (32) and acts between said fixed stroke limiter (33) and a collar (38) of said stem.

Inventors: ERRANI DEO, ERRANI, DEO
Applicants: ITALIANA SERRATURE AFFINI, COSTRUZIONI ITALIANE SERRATURE AFFINI C.I.S.A. S.P.A.
Application year: 1993
Main classification: E05B47
IPC codes: E05B47, E05B15