"AN ANTI-TAMPERING SELF-BLOCKING DEVICE FOR SPRING LATCH OR HOOK LOCKS"

The present invention concerns an anti-tampering self-blocking device for spring latch or hook locks.

It is known that most of the locks used at present are spring latch or hook, automatic spring locks; while for their opening it is necessary to operate handles, knobs, keys or other control means, by means of which said spring may be released, for the closing it is sufficient to push the door or other mobile object to which the lock is applied, into its closed position or against its pendant as, during said operation, said spring latch or hook is opened by the contact of said pendant and are closed again by said springs.

Usually, said spring latch locks are used in doors or other similar objects rotating on hinges, while the hook locks are generally used in sliding doors and other similar objects.

Above mentioned locks are of comfortable, practical and quick use, but the inconvenience consists in that the spring latchs and the hooks are easy to be opened from outside with the help of any kind of thin sheet introduced in the space between the pendant and the door or other mobile object to which said locks are applied, thus offering a limited safety degree.

For overcoming said inconvenience, said locks are usually not used alone but together with additional safety devices, often consisting of integrative bolts that may be closed with a key, or of blocking devices of the spring latchs and hooks that may be closed with a key, which however at least partially frustrates the convenience, practicality and quick use which are the main purpose of said kind of locks.

All above mentioned inconveniences are definitely overcome by means of the device according to the present invention, which not only prevents the spring latchs or the hooks from being opened from outside with no other means than the provided handles, knobs, keys or other control means, but which also completely saves the convenience, practicality and quick use of the spring latch and hook locks, without interfering with their functioning automatisms.

The anti-tampering self-blocking device for spring latch or hook locks according to the present invention is applicable to locks with spring latchs or hooks or other closing elements which may assume two positions: a closing position, under the action of a spring, and an opening position, under the action of special operating elements like handles, knobs, keys or latches for their control or combinations thereof, or under the action of any other push performed directly onto said spring latchs or hooks or other closing elements.

The anti-tampering self-blocking device for spring latch or hook locks according to the present invention comprises therefore:

- a first means, operated by the elements for operating locks, like handles, knobs, keys, latches for their control or combinations thereof, which may perform two movements: one for opening the spring latchs or hooks and one in the direction opposite to the first mentioned one;

- a second means which may assume two positions, one for blocking the spring latchs or the hooks, assumed under the effect of a spring, and one for releasing said spring latchs or hooks, assumed under the action of said first means during its opening movement of said spring latchs or hooks;

- a third means that may assume two positions, one for blocking said second means, assumed under the action of a spring, and one for releasing said second means, assumed either under the action of said first means by means of a movement opposite to the movement for opening said spring latchs or hooks, or under the action of said spring latchs or hooks when those are solicited by any other push performed on them from outside; furthermore, the position of said second means for blocking the spring latchs or the hooks, also blocks said third means in its position of blocking the second means.

The advantages of the anti-tampering self-blocking device for spring latch or hook locks according to the present invention are evident.

The anti-tampering self-blocking device for spring latch or hook locks according to the present invention will be described more in detail hereinbelow relating to the enclosed drawings in which some embodiments are shown.

Figure 1 shows a lateral, partial section view of a spring latch lock with pendant, operated by means of rotable handle and applied thereto a preferred embodiment of the anti-tampering self-blocking device for spring latch or hook locks according to the present invention, in closed position.

Figures 2 and 3 show the lock according to claim 1 , respectively in a just begun opening and in a completed opening, while figure 4 shows its open position.

Figure 5 shows the device during an automatic closing performed by means of a push of said lock towards the pendant.

Figure 6 shows a partial section plan view of the lock according to figure 5, shown also in figure 7 during a closing performed with the help of a handle.

Figure 8 shows an axonometric view of the first, second and third means.

Figure 9 shows a lateral view in partial section of a spring latch lock complete with pendant, operated by means of a sliding latch, in which also an other embodiment of the device according to the present invention is applied, in closed position.

Figure 10 shows a lateral view in partial section of a hook lock, complete with pendant, operated by means of a rotating handle or key, whereto an other embodiment of the device according to the present invention is applied, in closed position.

The enclosed figures show an anti-tampering self-blocking device for spring latch or hook locks according to the present invention, comprising:

- a box 7 and a pendant 1 ;

- a prismatic shaft rotating around its own longitudinal axis, and a handle 12, integral therewith;

- a spring latch 21 sliding in horizontal sense, provided with a return spring 2 and with ends 20 and 6;

- a first means 11, integral with said rotating prismatic shaft 10 and provided with a return spring 13 and with ends 5 and 14;

- a second means 4, rotating around a pin 8 and provided with a return spring 9 and with ends 3 and 16;

- a third means 17, rotating around a pin 18 and provided with a return spring 15 and with ends 19 and 33;

- a number of arrows, whereof 22 shows the direction of the opening manoeuvres of handle 12, 23 shows the direction of the

opening said spring latch 21, 24 shows the direction of the relative motion of the lock towards said pendant 1 during the closing push, and 26 shows the direction opposite to the opening manoeuvre of said handle 12;

- a sliding latch 27, whereby arrow 28 shows the direction of the opening manoeuvre, with a first, second and third means 35, 34 and 36, in the variant of the device according to the present invention applied to the spring latch lock operated by said sliding latch;

- a movable hook 30, whereby arrow 29 shows the direction of the opening movement, with handle 31, the key cylinder 32, a first means 37, a second means 39 and a third means 38, in the variant applied to the hook lock, operated by rotating handle and key.

Relating now to the details of the enclosed figures, the functioning of the anti-tampering self-blocking device for spring latch or hook locks according to the present invention may be described as follows:

- in the disposition shown in figure 1, the spring latch 21 can not move in the direction of arrow 23 even if directly solicited by an external force operating in such direction, as its end 20 is blocked by end 3 of the second means 1, which in turn is blocked against end 19 of the third means 17 by the action of a spring 9, and said third means in turn is blocked against end 3 by effect of a spring 15, and also the first means 11 does not move because it is kept by a spring 13 so that the door, or other movable object of application, is surely and safely close;

- when the handle 22 is rotated in the direction of arrow 22, involving also said first means 11 in its rotation by means of a shaft 10, first end 14 of said first means 11, pushing end 16, makes said second means 4 move and its end 3, disengaging end 20 of the spring latch 21 from the block performed by said end 3 - as shown in figure 2 — and then end 5 of said first means 11 , moving said end 6, makes said spring latch 21 move in the direction of arrow 23, as shown in figure 3 and the door, or other movable object to which the lock is applied, may be opened;

- when sad handle 22 is released, the parts assume spontaneously , under the push of the springs, the positions shown in figure 4, with the spring latch of the lock projecting but not blocked, as the end 19 of the third means 17, pushed against end 20 of spring 15, prevents end 3 from returning into the position shown in figure 1 ;

- the door, or other movable object, which now is open, may be closed again in two ways: automatically, simply pushing it towards its pendants, or pulling it to by the handle, keeping it turned and the spring latch open during the closing so that, in the first case - shown in figures 5 and 6, the contact with the pendant 1 due to the approaching movement in direction 24, moves said spring latch 21 in direction 23 and consequently end 20 moves end 19 beyond said end 3, thus allowing it to keep said end away from said end 20 so that, once the contact between the pendant and the spring latch is finished, the component part return, under the push of the springs, into their positions shown in figure 1 and the spring latch is blocked again while, in the second case, end 19 is moved beyond end 3 not

by the action of end 20 of said spring latch 21, as in the preceding way, but by the action of end 14 of said first means onto end 33 of said third means, by means of a movement of said handle 12 in the direction of arrow 26, thus obtaining the final blocking of said spring latch 21 so that the door or similar once closed, can be opened again only by means of the handle, as said spring latch 21 ma be operated only by the latter, and it is safely blocked against any other action performed from outside onto it in any way.

The anti-tampering self-blocking device for spring latch or hook locks according to the present invention may be applied to all automatic, spring spring latch or hook locks operated by handles, knobs, keys, control latches or combinations of them all.

For exemplifying purposes, figures 9 and 10 respectively show a variant applied to a spring latch lock operated by means of a sliding latch, and a variant applied to a hook lock operated by a handle as well as by a key.

The considerable advantage of the anti-tampering self-blocking device for spring latch or hook locks according to the present invention consists in that when applied to automatic, spring hook or spring latch locks, it determines that the latter may be opened only by means of fitting handles, knobs, keys, latches or other control means, while they remain blocked under any other action from outside directly operating on the spring latch or the hook, thus

assuring the maximum safety against undesired opening efforts from outside without the need of any other additional means, at the same time saving the comfortable, practical and quick use of this kind of locks, as it allows always the immediate opening by fitting handles, knobs, keys, latches or other control means, and the easy automatic push closing.