Sash Lock

This invention relates to a sash lock, particularly to a sash lock, wherein a latch cam may be locked when said latch cam is engaged with a keeper.

An object of this invention is to provide a sash lock which may lock the latch cam and may not easily be opened from outside.

Another object of this invention is to provide a sash lock which may easily be locked or unlocked from inside by means of a key.

Still another object of this invention is to provide a sash lock which has a latch cam of, simple, compact and strong structure while its external appearance is fine and its locking and unlocking is easy.

According to this invention, there is provided a sash lock which comprises a rotatable latch cam pivoted to a base and engageable with a keeper, a locking member for locking and unlocking the latch cam, a rotatable actuating member for shifting the locking member to a locked position or an unlocked position, and a key for rotating the actuating member.

These and other objects as well as characteristics of this invention will be apparent to persons skilled in the art from the study of the following description with reference to the accompanying drawings, in which;

FIG. 1 is a perspective view of a sash lock according to this invention, showing it in a state where it has an unlocked latch cam.

FIG. 2 is a vertical longitudinal section of the lock of FIG. 1, showing it in the same state.

FIG. 3 is an exploded perspective view of the lock of FIG. 1.

FIG. 4 is a perspective view of a cylinder forming part the lock, turned upside down.

FIG. 5 is a perspective view of an actuating member turned upside down.

FIG. 6 is a perspective view of the latch cam turned upside down.

FIG. 7 is a front view, showing various profiles of keys usable in the lock.

FIG. 8 is a sectional view, showing various sectional shapes of such keys.

FIG. 9 is a plan, showing various shapes of upper portions of actuating members according to FIG. 5.

FIG. 10 is an enlarged plan, showing the combination of a key with a key hole of the actuating member.

FIG. 11 is a perspective view, showing another example of an actuating member.

Referring to FIG. 1, there is shown a sash lock comprising a base member (1), having holes for screws (not shown) for securing this member to a first sash member. A latch cam (2) is pivoted to the base member for latching this member to a second sash member. The sash members are well known and are not shown. The latch cam can be engaged with a keeper (not visible in this figure. There is also provided a casing (3) to cover a means for locking the latch cam from rotating relative to the base member. As shown in FIG. 1 the latch cam (2) is in a rotatable state relative to the base member (1), namely in an unlocked state. In this unlocked state, when a key (4) is inserted into a key hole (6) of a rotatable barrier disk (5) lying in the top of the casing (3) as shown, and when the key is turned clockwise, then a locking means within the cylinder acts in such a manner that the latch cam (2) can not be rotated relative to the base member (1). In the so established locked state, when the key (4) is turned counter-clockwise, the latch cam (2) is unlocked so that it may be rotated relative to the base member (1). In the unlocked state of latch cam (2), the latch cam can be turned nearly 180.degree. to engage with the keeper or to disengage therefrom.

Referring to FIG. 2 to FIG. 6 inclusive, latch cam (2) has a shaft (8) integrally formed on and normal to the underside or back of its plate portion (7) and this shaft rotatably passes through a central opening (10) in a top wall (9) of the base member (1), and through a central opening (12) in a washer (11) which closes the back of the base member. by caulking the tip (13) of the shaft, it is pivotally attached to the base member.

Between the base member (1) and the washer (11), there is a space (14), in which two leaf springs (15) are secured to the underside of the base member so as to pinch the rotatable shaft (8) elastically. A flat side face (16) is formed on the rotatable shaft (8) and when the latch cam (2) is located either in engaged position with the keeper or in a position disengaged therefrom, the leaf spring (15) engages with the flat side face (16) of the rotatable shaft to keep the latch cam in the respective positions.

Cylindrical casing (3) has projections (17) on its lower end, and these projections are inserted in openings (18) of the plate portion (7) of the latch cam (2) and are secured by caulking the tip of the projections. Within casing (3), there is provided a locking means as follows. The rotatable barrier disk (5) having the key hole (6) engages with a flange (19) inwardly projecting at the top of the casing (3), and is kept thereby so as not to get out from an opening (20) at this top of the casing. A locking member (21), which can lock latch cam (2) so as not to rotate relative to the base member (1), is located between rotatable barrier disk (5) and the plate portion (7) of latch cam (2), and has a body (33) having an annular (peripheral) face. Two legs (23) extend from said body, parallel to cam shaft 8, at diametrically opposite points of the body. Said legs (23) are always inserted in two guide openings (24) of the plate portion (7) of the latch cam (2), and are slidable in these openings to shift the locking member (21) only in axial directions.

When locking member (21) slides into a lowered position, the two lower ends of the legs (23) engage within two notches or recesses (25), which are symmetrically formed around the central opening (10) of the base member (1), thus to lock the latch cam (2). When the locking member (21) slides into a raised position, the lower ends of the legs (23) do not engage with the recesses (25), and the latch cam (2) is then rotatable, being unlocked. Between the locking member (21) and the latch cam (2), a coiled compression spring (26) is provided and it acts so as to shift the locking member upwards into unlocked position. Between rotatable barrier disk (5) and locking member (21), an actuating member (27) is provided to shift locking member (21) into its locked and unlocked positions by rotation of the actuating member while the spring (26) tends to keep the locking member raised.

To convert the rotary motion of actuating member (27) into the axial rectilinear motion of locking member (21), the actuating member and the locking member are provided with mutually engageable cams. The cam of actuating member (27) comprises two projections on the lower face of the body (28), each having a configuration similar to a saw-tooth, comprising a lower (recessed) flat cam surface (29), an inclined cam surface (30) continuous to said lower flat cam surface (29), a higher (projecting) flat cam surface (31) continuous to said inclined cam surface (30), and an upright cam surface (32) continuous to said higher flat cam surface (31).

The cam of locking member (21) similarly comprises two projections on the upper face of body (33), each having a lower (recessed) flat cam surface (34), which may engage with the higher flat cam surface (31) of actuating member (27), an inclined cam surface (35) which is continuous to lower flat cam surface (34) and may engage with the inclined cam surface (30) of the actuating member, a higher (projecting) flat cam surface (36) which is continuous to inclined cam surface (35) and may engage with the higher flat cam surface (31) and with the lower flat cam surface (29), and an upright cam surface (37) which is continuous to higher flat cam surface (36) and may engage with the upright cam surface (32) of the actuating member.

When the higher flat cam surface (31) of actuating member (27) engages with the lower flat cam surface (34) of locking member (21), as shown in FIG. 2, the locking member (21) is in its higher position, namely its unlocked position, and the legs (23) of the locking member do not engage with the recesses (25) of the base member (1), but engage with the guide openings (24) only, thus the latch cam (2) is unlocked. In this unlocked state, the actuating member (27) is rotated clockwise by inserting the key (4) through key hole (6) of rotatable barrier disk (5) into a key hole (38) of the actuating member and turning the key clockwise. Accompanied with this rotation of actuating member (27), the inclined cam surface (30) of the actuating member (27) slides on the inclined cam surface (35) of locking member (21) to push down this member against elasticity of the spring (26), thus the higher flat cam surface (31) of actuating member (27) is engaged with higher flat cam surface (36) of the locking member (21). The locking member (21) is thereby shifted downwards to the extent of the height of both higher flat cam surfaces (31) and (36), and legs (23) thereof then engage with both of the guide openings (24) of the latch cam (2) and the recesses (25) of the base member. Thus the latch cam (2) is locked.

In this locked state, when the actuating member (27) is turned counterclockwise by the key (4), the higher flat cam surface (31) of actuating member (27) is disengaged from the higher flat cam surface (36) of locking member (21) to engage with the lower flat cam surface (34) of locking member (21) while the higher flat cam surface (36) of locking member (21) will engage with the lower flat cam surface (29) of actuating member (27). Thereby locking member (21) is raised by coiled spring (26) to the extent of the height of both of higher flat cam surfaces (31) and (36) into the original unlocked position, to disengage its legs (23) from the recesses (25) of the base member, thus the latch cam (2) is unlocked.

Actuating member (27) has a shaft (39), which integrally extends axially from the lower face of body (28), and has two projections (40) integrally extending radially from the periphery of the body (28). Shaft (39) is rotatably fitted into a central opening (41) of body (33) of locking member (21) for rotation relative to actuating member (27) and locking member (21) Projections (40) are extending into a space between two raised portions (42), which are disposed on an inside face of the peripheral wall of casing (3). The projections can rotate between these portions to limit rotation of actuating member (27). In the embodiment shown in the drawings, the rotation is limited to 90.degree., and when the projections (40) abut against one of raised portions (42), the locking member (21) is in locked position, when the projections abut against another raised portion (42), the locking member (21) is in unlocked position.

Between actuating member (27) and rotatable barrier disk (5), there is provided a washer (43), which has a central opening (44) for rotation of the key (4) within, and slots or notches (45) on its periphery. Slots (45) fit the raised portions (42) within the casing (3) to prevent the washer (43) from rotation relative to the casing (3). If any improper key, driver, coin, or the like is inserted into the key hole (6) of the barrier disk (5) to turn the actuating member (27) by the mere application of frictional force between the barrier disk and the actuating member (pushing the barrier disk (5) on the actuating member (27) and turning the disk), washer (43) prevents the turning force of the barrier disk (5) from being transmitted to the actuating member (27), and thus the actuating member (27) will not be rotated. Therefore, the latch cam (2) cannot be unlocked by any key other than the regular one, inserted with member (27) itself.

In case that the rotatable barrier disk (5) and the actuating member (27) are made of metallic material and the coefficient of friction between them is relatively large, washer (43) is effectively used to lessen the coefficient of friction. However, in case that the actuating member is made of synthetic resin having self-lubricating property with small coefficient of friction, washer (43) may be eliminated and barrier disk (5) may contact directly the actuating member (27). In addition, the frictional resistance between the cam surface of actuating member (27) and the cam surface of locking member (21) is lessened thereby, and it becomes possible to turn the actuating member (27) lightly.

The tip of key (4) may have various profiles (Fa), (Fb), (Fc) and the like, as shown in FIG. 7, and may be formed with various sectional shapes (Wa), (Wb), (Wc) and the like as shown in FIG. 8, thus a large number of different keys may be provided by combining these profiles and shapes.

The key hole (6) of the barrier disk (5) is formed to tally or correspond with one kind of sectional shape of the key so that it can be traversed only by the key having a corresponding sectional shape, and the key hole (38) of the actuating member (27) is formed into shapes (38a), (38b), (38c) to tally or correspond with the profiles of the key, so that it can only be engaged with the tip of one proper key among a plurality of keys having the corresponding sectional shape as shown in FIG. 9.

The width of the key hole (6) of barrier disk (5) may be made somewhat larger than the thickness of the key (4) so that keys having different sectional shapes may be inserted into said key hole. FIG. 10 shows one such case, wherein either of two different keys, having two kinds of sectional shapes (Wb), (Wc), can be inserted into the key hole (6) of the barrier disk (5).

In case the key hole (38') is not formed directly in body (28) of actuating member (27), but the key hole (38') is formed in a plate (46) which may be separated from body (28) of said actuating member (27), a large number of plates (46) having various key holes may be formed and these plates may be combined with the body (28) of a common actuating member (27), thus the production of actuating member is simple (FIG. 11). Plate (46) may be a rectangular sheet; its key hole (38') may be similar to the key hole (38) of the actuating member (27) as mentioned above; a projection (47) is formed on its periphery. On upper face of the body (28) of the corresponding actuating member (27'), there are formed a groove recess (48) in which said plate (46) will fit notch or recess and a (49) of groove (48), in which projection (47) will fit; and both members (27) and (46) will be integrally joined by inserting said plate (46) into these recesses (48) and (49).

It is to be understood that the present invention is not limited to the above mentioned embodiments thereof, but may be otherwise variously modified within the scope of the invention set forth in the following claims.