The invention can be applied to a large range of applications, but is particularly useful for securing sliding doors and windows, and therefore mainly described in that context.

Presently, locks for slidable doors can be used only in the completely locked position where the door is tightly shut against the door jamb, requiring high precision matching of the contacting surfaces.

It is however sometimes desirable to lock one member against the other in a certain, small distanced relation to each other. For example, in the case of slidable windows, say during summertime, one would sometimes wish to leave the windows slightly open, allowing a breeze of air to flow between the wings (or wing and window jamb), but still to maintain security against burglary.

It is therefore the general object of the invention to provide a device for locking to each other a pair of members that need to not be, when in the locked position, tightly engaged to each other.

It is a further object of the invention to provide a locking device of a universal nature, namely that can be useful for various purposes and applications.

It is a still further object of the invention to provide a locking device based on enhanced friction engagement between a male and a female members securable at different relative locations.

SUMMARY OF THE INVENTION It is thus provided according to the invention a locking device for locking a first member to a second member comprising: a male lock member comprising a spindle formed with a first flat friction surface and means for mounting the spindle onto one of the members; a female lock member comprising a prismatic friction member nested within a first cavity formed in the block-like lock member, the cavity having opposite side surfaces configured to support a reciprocating sliding movement of the prismatic friction member thereinside, means for guiding the reciprocating sliding movement of the prismatic friction member, a second cavity formed in the block-like lock member, merging from the first cavity and configured to freely receive the spindle of the male lock member, spring means urging the prismatic friction member in the direction of the second cavity, a second flat friction surface, mating the first friction surface formed at the side of the prismatic friction member facing the second cavity, so that during insertion of the spindle into the second cavity, the first and the second

friction surfaces slide one on the other against the urge of the spring means and locking means for arresting the prismatic friction member against the reciprocating movement thereof in the friction surfaces mating relations.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more clearly understood in the light of the ensuing description of few preferred embodiments thereof, given by way of example only with reference to the accompanying drawings, wherein: Fig. 1 a is a perspective view of a female lock member provided according to the teachings of the present invention; Fig. 1 b is perspective view of a male lock member of the lockingdevice; Figs. 1 c, 1 d and 1 e represent alternative designs of friction engaging surfaces of the male and female lock members ; Fig. 2 is a fragmental section taken along line ll-ll of Fig. 1a; Fig. 3 is a sectional view taken along line Ill-Ill of Fig. 2; Fig. 4 is a cross-sectional view of the female device member of Fig. 2 in the engaged, locked position; Fig. 5 illustrates the application of the locking device according to the invention to a slidable door or window closing against a door or window jamb ;

Fig. 6 illustrates the mounting of the locking device for the application of the embodiment of Fig. 5; Fig. 7 is a cross-sectional view illustrating the partly locked position of the device of the example of Figs. 5 and 6; Figs. 8 and 9 are modifications of the embodiments of Figs.

2-4; Figs. 10 and 11 illustrate the application of the locking device according to the present invention to lap-top computers; and Fig. 12 is a modification of the embodiment of Figs. 10 and 11.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to Fig. 1 a there is shown a female locking member generally denoted 10 of a block configuration 12. Block 12 has right and left sides 12a and 12b, and panel side denoted 12c, and is formed with a first, throughgoing rectangular passage 14, merging into a second, mostly circular passage 16.

Within the passage 14, a prismatic lock member 18 is freely seated, recipocable in the up and down directions. The lock member 18 is provided at its bottom side with a friction surface denoted 18a, which may be of various types--see Figs. 1 c-1 e.

The reciprocating movement of the lock member 18 can be blocked by the operation of a standard push-in lock designated 22,

using a key 23 (see Fig. 4), a rotatable cylinder lock (see Fig. 8), or any other suitable key-operated locking devices.

The counter-part of the female lock member 10, namely the male locking member 24 of Fig. 1 b comprises a generally circular spindle-like member 26, being formed with a flat surface 28 bearing thereon a complementary friction surface 28a as will be described below. A facet 28b is preferably formed as shown. The diameter of the spindle 26 is slightly less than that of the circular passage portion 16 of the female member 12, so as to be freely insertable thereinside.

The spindle 26 is carried by a mounting bracket generally denoted 30 of any suitable shape which may be changed according to the application of the locking device (e. g. see Fig. 12). In the described example, the bracket 30 is provided with mounting legs 32a and 32b with suitable screw openings as shown.

Preferably, for neutralizing altogether the application of the lock, the spindle 26 may be pivotally mounted to the bracket 30 e. g. by a pin 34.

As shown in more detail in Figs. 2 and 3, the reciprocable friction member 18 is held between walls 14a and 14b of the rectangular passage 14 in a freely slidable manner, guiding means being provided in the form of at least one--but preferably two-- guide pins 40a and 40b (Fig. 3), passing through guide slots 42a

and 42b, respectively, for allowing a limited up and down movement of the friction member 18. In the non-operative position shown in Fig. 2, the friction member 18 is urged by one or more springs 44 pushing from above so that the friction surface 18a bulges or projects into the circular passage portion 16. The spring 44 may be installed and supported by press-fit insert pin 45 as shown.

The friction member 18 is further formed with a bore 46, of such location and size as to cooperate with the push-in lock device 22 (or equivalent thereof--see Figs. 8 and 9) which is installed as shown.

As already mentioned, the mating friction surfaces 18a and 28a may take several forms. Thus, in Fig. 1 c the surfaces are simply zig-zaged; in Fig. 1 d--there is provided one (or more) rounded rib, adapted to snap into any of the series of grooves constituting the friction surface 28a; and Fig. 1 e shows the reverse arrangement.

As evident from Fig. 4, presenting the operative, locked position of the device, the insertion of the spindle 26 into the passage 16 will cause the frictional engagement of the surfaces 18a and 28a, while the member 18 clicks up and down over the friction surface 28 of the spindle 26, and against the bias of the spring 44. At any selected location, namely any depth of insertion of the spindle 26 into the cavity 16, a locking position is attainable by pushing the locking detent 22a of the push-in lock 22 into the bore 46 of the friction member 18. This arresting or fixation will prevent further insertion or,

more importantly, retrieval of the spindle 26, since the frictional movement of the friction member 18 over the spindle 26 will be blocked.

While the locking device so far described may be used for general applications, it is particularly useful for locking sliding (and also hinged) doors or window-wings, as will be now exemplified with reference to Figs. 5-7. As schematically shown, a slide door (or window) generally denoted D is closable against jamb J. The female locking device generally denoted 110 is mounted to a side frame member F1 of the door D, whereas the male member 124 is mounted to frame member F2 as clearly seen in Fig. 6. The female member 110 is mounted by screws fitting into suitable bores formed in the block-like casing 112 of the female member 110 and the male member is mounted by screws as shown in Fig. 6.

The unique feature achieved by the locking device of the present invention is vividly illustrated in Fig. 7, namely that an intermediate locking position is attained where a gap L is left between the door D and door jamb J for the free flow of air in-between even though the locking device is in its locked position protecting against unauthorized, forceful intrusion.

In the embodiment of Figs. 8 and 9, the push-in lock 22 is replaced by a common, cylinder-type, eccenter-pin mechanism.

Hence, it will be readily understood that the off-center pin 222a of

the lock 222, through rotation by the key 223, changes its location from the operative, locking position shown in Fig. 8, where the female lock member 118 is locked by the friction engagement with the spindle 226, into an unlocked position by rotating the pin 222a by 180° (shown in dashed-lines in Fig. 9).

In the application of the invention exemplified in Figs. 10 and 11 there is shown a lap-top computer generally denoted 300 with female locking member 310 and male locking member 324 mounted at the base and cover of the computer, respectively. The female, block-shaped member 312 is mounted by a base plate 350, and the male member--by a base plate 352.

In the locking position (Fig. 11) the spindle 326 may form an anchor for tying the computer to an immovable object 354, against theft thereof, by a cable 356.

According to the modification of Fig. 12, the male friction member 424 comprises spindle 426 which is detachable from the cover of the computer 400. This will enable the use of safety cable 456 also when the computer is in its operative, open-cover position.

Those skilled in the art will readily understand that numerous changes, modifications and variations and additional applications may be applied to the invention as hereinabove exemplified without departing from the scope of the invention as defined in and by appended claims.