Latching mechanism for cupboard doors and drawers

The invention relates to a closure device for cabinet doors and drawers, which serves in particular as securement against unauthorized actuation by children. On the outside of a cabinet door or drawer, two push-buttons are herein provided the spacing of which from each other is greater than the distance which can be bridged by the hand of a child. Only if both push-buttons are actuated can the cabinet door or drawer be opened.

BACKGROUND OF THE INVENTION 
The invention relates to a closure device or latching mechanism for cabinet 
doors and drawers. 
As a rule, cabinet doors and drawers can readily be opened from the 
outside. However, this is especially of disadvantage if objects are 
disposed within the cabinets, which are not intended to be accessible to 
everyone, and especially not to children. Among these objects are knives 
and forks, cleaning agents or medications. 
A closure for drawers is already known which is said to ensure that food 
items disposed in the drawer do not dry out (U.S. Pat. No. 1,906,723). In 
the case of this drawer closure, however, a complex and additional 
mechanism is necessary since the drawer is to be closed airtight. 
Furthermore, a securement device for gates or the like is known in which a 
drive with two sides is required (DE 92 14 278.8 U). This securement 
device, moreover, comprises a locking latch movable by the force of a 
spring in a recess. This securement device, primarily intended for gates 
which can be raised and lowered in lateral rails, is not suitable for the 
securement of cabinet doors and drawers. 
In a known childproof closure for cabinets disposed under sinks, which does 
not require a key and yet cannot be opened by children, a snap closure is 
provided which is actuated via a wire pull by means of a pull knob (DE 34 
08 791 A1). The pull knob is disposed such that the distance between pull 
knob and door handle is so large that with an infant's hand, it is not 
simultaneously possible to reach the two, as is required for opening the 
door. 
Further is known a snap latch-bar device for doors and gates which 
comprises a guide housing and an actuation housing connected with each 
other (DE 78 37 900 U). In the guide housing is disposed a latch bar which 
at its one end bears a snap latch-bar which is prestressed into a locking 
position by a helical compression spring. At the other end of the snap 
latch-bar is disposed a yoke which is located in the actuation space. This 
yoke is part of a double-action actuating mechanism, which comprises a 
rotatable press-keyed nut and two press-keyed nut arms. When rotating the 
press-keyed nut, the latch bar is pulled downwardly regardless of whether 
or not the press-keyed nut is rotated in the clockwise or in the 
counterclockwise direction. This known device is too complicated for a 
child safety mechanism since it requires a tool in order to rotate the 
press-keyed nut. 
Furthermore is known a closure for a medicine cabinet which can only be 
opened with the aid of two hands (U.S. Pat. No. 2,759,782). On the 
medicine cabinet are provided two slide levers of which the one must be 
moved horizontally and the other vertically in order to open the door of 
the medicine cabinet. If they are operated with the finger and thumb of 
one hand, the door does not open because the resulting forces are directed 
away from the suspension of the door. In order to open the door, the 
second hand must be used additionally. 
In the case of another known snap-in mechanism for cabinets and the like, 
means are provided which permit adults, but not children, to open a door 
(U.S. Pat. No. 2,924,477). This snap-in mechanism comprises two snap 
elements which are affixed on the cabinet with one of these elements being 
fastened on the housing frame and the other element on the door. In 
addition, this mechanism comprises two actuation members rotatably 
disposed in the cabinet and comprising levers projecting from a side wall 
so that they are accessible from the outside. These levers are partially 
encompassed by a covering with an opening which permits limited access to 
the levers. In order to open a door, thumb and finger of a person must be 
inserted into said openings and the levers must be pressed together. A 
child with smaller fingers is not capable of inserting its fingers 
sufficiently far into said openings. 
Further a security closure for containers, in particular medicine cabinets, 
is known, which makes it impossible for children to open a door (U.S. Pat. 
No. 3,519,299). The security closure comprises a locking as well as an 
unlocking mechanism on the container and a portion of the unlocking 
mechanism projects from the container. The portion of the unlocking 
mechanism disposed in the container is associated with the locking 
mechanism while the other portion comprises an enlarged gripping surface 
which is greater than the normal reach of a small child, but smaller than 
the reach of the hand of an adult. Furthermore, an additional unlocking 
mechanism is provided on the container which cooperates with said 
unlocking mechanism. 
A further safety closure intended for medicine cabinets is used in a 
refrigerator (U.S. Pat. No. 3,603,657). This refrigerator includes a 
safety shelf for medications which must be stored at low temperatures. The 
locking mechanism of this safety shelf is an invisible and integral part 
of the refrigerator door. It is opened by merely touching or pressing one 
or several sites on the door. As actuation elements two push-buttons are 
preferably provided which, upon being actuated simultaneously, close a 
circuit whereby a door is opened. 
Another known securing closure for a medicine box comprises a first and a 
second set of push-buttons and each set comprises two push-buttons and 
each push-button within the set is disposed at an interval from another 
push-button (U.S. Pat. No. 3,893,721). This interval is greater than the 
average interval between the thumb and any other finger at one hand of a 
child but smaller than the average interval between the thumb and any 
other finger of an adult. 
Lastly, a pistol case with a security lock is known which cannot be 
defeated by a child (U.S. Pat. No. 5,172,575). In order to open this case, 
it is necessary to place two of four feet of the case onto a level surface 
so that they are activated. Any person not understanding the role of the 
feet of the case in opening or closing, is unable to open this case. 
SUMMARY OF THE INVENTION 
The invention therefore addresses the problem of creating a latching 
mechanism for cabinet doors, drawers or the like which can be operated 
readily by adults and not at all by children. 
The advantage achieved with the invention resides in particular therein 
that the child-proofing mechanisms does not require any special opening 
aids. Rather, the fact is utilized that a child's hand is smaller than 
that of an adult and, accordingly, does not have a reach greater than a 
specific distance. In practice, this distance marked by two buttons is 
between 0 and 150 mm, preferably between 80 and 130 mm. Moreover, it is 
additionally possible to adjust the force required to overcome the 
securement. This force is adjusted so that it cannot be brought to bear by 
children.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
In FIG. 1 is shown the front of a cabinet under a sink 1, comprising a base 
2, two doors 3, 4, two drawers 5, 6 and a working plate 7. The drawers 5, 
6 as well as also the doors 3, 4 are each provided with a recessed grip 8, 
9; 10, 11. Behind each door 3, 4 one locking device 12, 13 is provided, 
each of which comprises two operating buttons 14, 15 or, respectively, 16, 
17. The spacing of these buttons 16, 17 from each other is therefore 
selected such that they cannot be operated simultaneously by a child's 
hand. A distance of 80 to 130 mm is sufficient for this purpose. The 
buttons 14, 15 also have the same spacing as the buttons 16, 17. It is 
harmless if a child can simultaneously actuate with both hands the buttons 
14, 15 or, respectively, 16, 17, since he needs one more hand in order to 
pull open the door at the recessed grip 10, 11. In order to open one door 
3 or 4 it is required to oppose at the recessed grips 10, 11 the forces 
acting on the buttons 16, 17 with a counterforce. 
In FIG. 2 the door 3 is shown broken at a site 18 so that the locking 
mechanism 12 can be seen clearly. The buttons 14, 15 are herein supported 
in guides 19, 20 in each of which is disposed a compression spring which, 
however, is not visible in FIG. 2. Both buttons 14, 15 are disposed within 
a housing 21 which comprises an opening on one side. This housing 21 is 
shown in further detail in FIG. 3. Under the guides 19, 20 are disposed 
slide bars 22, 23 which are guided on the housing bottom 55 by guide bolts 
24, 25. At the front end of a slide bar 22, 23 where the guide bolts 24, 
25 are disposed, is provided in each case an angled lever 26, 27 rotatable 
about an axle 28, 29 with the aid of the slide bar. The angled levers 26, 
27 are each connected via an articulation 56, 57 with an intermediate 
lever 30, 31 at the ends facing away from the slide bars 22, 23, which 
intermediate lever is coupled via bolts 32, 33 with the ends of a carrier 
34. This carrier 34 comprises an elongated bridge piece with edge 
elevations on both sides which serve for strengthening and stabilizing the 
carriers comprising synthetic material. In the center of the carrier 34 is 
provided a bolt 35 connected with a locking bar 38. A snap-in stop element 
36 is fastened on a strip 37, which engages the locking bar 38. The 
locking bar 38 is additionally connected to a compression spring 39. A 
guide pin 40 is inserted through a slot of the locking bar 38 so that the 
locking bar 38 can be moved back and forth. 
In FIG. 3 the door 3 with the locking device 12 is shown in a view from 
above, i.e. the view corresponds to the direction of arrow 45 in FIG. 2. 
Herein the button 14 with the guide 19 as well as the strip 37 is shown. 
The housing 21 with the housing bottom 55 delimits the mechanism with 
respect to the interior of the cabinet under the sink. On the housing 
bottom 55 are disposed the axle 56, the bolt 32, and the intermediate 
lever 30. The slide bar 22 is disposed next to the axle 56 and under the 
guide 19. The end of the locking bar 38 is also depicted. 
FIG. 4 shows a detailed view of the button 14 disposed in guide 19 of door 
3. In guide 19 is disposed a compression spring 46 which is braced against 
the bottom 47 of guide 19 and which exerts pressure against the underside 
of button 14. Button 14 together with a square bolt forms a common part 
which is bevelled at its lower end. The bevel 49 of the square bolt 48 
corresponds to a bevel 50 of the slide bar 22. If the button 14 is pushed, 
the latter moves within guide 19 in the downward direction and the spring 
46 is compressed. Simultaneously, the square bolt 48 is displaced in the 
downward direction and the slide bar 22 is thereby moved to the left. This 
motion of slide bar 22 is terminated when the pin 24 abuts the wall 51 of 
opening 52. A securement pin 54 is intended to prevent the button 14 from 
popping out in the upward direction. 
The locking device 12 of FIG. 1 is again depicted in FIG. 5 and 
specifically at a point in time at which the button 14 associated with 
slide bar 22 has been depressed. Buttons 14, 15 are not shown herein in 
order to reveal the slide bars 22, 23 associated with these buttons 14, 
15. It can be seen in FIG. 5 that the slide bar 22 has been moved out and 
that in so doing it has rotated the angled lever 27 about the axle 28. 
Locking bar 38 is hereby pulled into housing 21, i.e. it is pulled away 
from the snap-in stop element 36 against the force of spring 39. This 
pulling-away, however, is insufficient to open the door 3 because by 
pressing only button 14, the carrier 34 is rotated about bolt 33 only so 
far that the locking bar 38 coupled via the bolt 35 with the carrier 34 is 
only displaced at the site of bolt 35 by half of the path required for 
unlocking. 
As can be seen in FIG. 5 each of the two slide bars 22, 23 is provided with 
three elongated holes 62, 63, 64 or, respectively, 65, 66, 67, in which 
guide bolts 24, 68, 69 or, respectively, 25, 78, 79 are disposed. 
FIG. 6 shows the same device as FIG. 5, however, at a point in time at 
which both buttons 14 and 15 are depressed. If only button 14 is 
depressed, then--as already described in connection with FIG. 5--only 
slide bar 22 is moved. This slide bar 22 presses against the angled lever 
27 which can be pivoted about axle 28. Since this angled lever 27 is 
connected through an articulation 56 with the intermediate lever 30, 
which, in turn, is connected via a bolt 32 acting as articulation with the 
carrier 34, the carrier 34 is pulled in the direction toward slide bar 22. 
The locking bar 38 coupled with carrier 34 in the process is pulled 
slightly back. The locking bar 38 guided by guide bolts 40, 61, 60 and 
fastened on housing bottom 55, thus leaves its starting position at a 
locking bar stop element 43 whereby, however, no complete unlocking is 
effected. 
But, when pressing the second button 15, the slide bar 23 associated with 
this second button 15--guided by bolts 25, 78, 79--is moved and rotates 
the angled lever 26 in the same way as angled lever 27 is rotated by slide 
bar 22. 
Through this rotary motion of the angled lever 26 the intermediate levers 
31 and the carrier 34 are moved. The carrier 34 is now in its center, 
defined by the carrier bolt 35 for the locking bar 38, displaced by the 
twofold magnitude. This twofold magnitude is sufficient to remove the 
locking bar 38 completely from the snap-in stop element 36. Therewith the 
door 3 is unlocked and can be opened by pulling the recessed handle 10. 
In order to be able to open the cabinet door 3, thus, for one, the distance 
between the two buttons 14, 15 must be bridged with the one hand and with 
the other hand the door 3 must be pulled. As a rule, for bridging the 
distance index finger and thumb are required. If the distance is more than 
130 mm, it can, as a rule, only be bridged by the hand of an adult. It is 
also not sufficient to press buttons 14, 15 only slightly; rather, they 
must be depressed so far that the slide bars 22, 23 can travel the path 
required to unlatch the locking bar 38. Thus, each one of the buttons 14, 
15 contributes to one half of the path of the locking bar 35. If only one 
button is pressed, the locking bar 35 is shifted by only one half out of 
the locking position and the locking system continues to remain locked. 
If both buttons 14, 15 are released after the opening, the locking bar 38 
is pushed back into the starting position by the compression spring 39, 
i.e. the door is locked again. In order to close the cabinet door 3, it is 
simply pushed shut. Hereby, the locking bar 38 snaps into the locking bar 
stop element 43 and locks the door. 
In FIG. 7 and FIG. 7a the carrier 34 is again depicted in a top view (FIG. 
7a) and in a side view (FIG. 7). It is evident that the carrier 34 
comprises at each end a bore 70, 71 and is provided in its center with 
bolt 35. Two reinforcement ribs are denoted by 72, 73. 
Locking bar 38 comprises a bore 74 which bolt 35 of carrier 34 engages. In 
addition, the locking bar 38 is provided with three elongated holes 75, 
76, 77 which the guide bolts 40, 60, 61 engage. The locking bar 38 is 
usefully bevelled at its end so that it can be moved by pushing against 
the snap-in stop element 36. This allows the locking bar 38 to snap in 
when pressure is exerted against door 3. 
The carrier 34 is shown in FIGS. 5 and 6, depicting to view, above the 
locking bar 38 so that its stud 35 projects downwardly and moves through 
hole 74.