EP2166185B1

EP2166185B1 - Articulated snap hinge

Info

Publication number: EP2166185B1
Application number: EP08425616.3A
Authority: EP
Inventors: Angelo Molteni
Original assignee: System Holz SpA
Current assignee: SYSTEM HOLZ Srl
Priority date: 2008-09-22
Filing date: 2008-09-22
Publication date: 2016-06-08
Anticipated expiration: 2028-09-22
Also published as: CN101684706B; CN101684706A; EP2166185A1

Description

The present invention relates to hinges having a snap-type opening and closing action, wherein a pair of articulated quadrilaterals, respectively secured to the door and to a wall of a piece of furniture, have some elements in common.
This kind of hinge is particularly widespread in those applications where it is desirable that a door can be firmly raised when open.
This is, for example, the typical case of cabinets placed in environments subject to shocks and vibrations, as in vehicles such as caravans and the like; said hinges allow a user to open or close a cabinet by turning the door by 90° with respect to a horizontal axis in order to move it from a raised condition to a lowered condition or vice versa, corresponding to an open or closed cabinet door.
The hinges keep the door stably closed or open by means of a snap mechanism, which includes one or more springs acting upon the articulated quadrilaterals of the hinges.
An example of this state of the art is described in European patent EP 745 172 , which relates to a hinge fitted with a spring that acts upon the ends of the rocker arms of one of the articulated quadrilaterals, which in turn are pivoted to the ends of the rocker arms of the other quadrilateral.
This hinge appears to be unsuitable for larger and heavier doors like those currently required by the market, because the spring can only exert a limited force due to the quite complex shape of the rocker arms of its articulated quadrilateral; therefore, it would in any case be impossible to use a bigger spring capable of exerting a stronger force.
A hinge for this type of application is known from European patent application EP1 138 857 , which hinge is equipped with two springs acting in series upon its articulated quadrilaterals.
In this case, the presence of a double spring allows the hinge to withstand the weight of larger doors, but at the same time it also increases the complexity of the hinge fabrication because of the limited spaces available in the articulated quadrilaterals.
The present invention aims therefore at overcoming what done in the state of the art.
It is therefore an object of the present invention to provide a snap hinge comprising two articulated quadrilaterals having some elements in common, wherein the elastic action of only one spring is sufficient, all other conditions being equal, to keep a cabinet door stably in the open condition.
It is a further object of the invention to provide a hinge that ensures smooth closing and opening actions, so that it can be secured to parallel or perpendicular mounting surfaces, as described below.
These and other objects are achieved through a hinge having the features set out in the appended claims; such features and the effects thereof will become apparent from the following detailed description of a preferred but non-limiting example of the invention, illustrated in the annexed drawings, wherein:

Figs. 1 and 2 show a hinge according to the invention, which for clarity has been depicted without the snap mechanism, in respective operating conditions;
Fig. 3 shows the previous hinge with two articulated levers of the snap mechanism, in an intermediate operating condition between those of Figs. 1 and 2;
Figs. 4, 5 and 6 show the hinge of Fig. 3 with the complete snap mechanism, in respective operating conditions;
Figs. 7 and 8 show the procedure for adjusting the spring pin of a variant of the hinge according to the invention;
Figs. 9, 10 and 11 are perspective views of the hinge of Fig.7 in respective operating conditions;
Figs. 12, 13 and 14 show the hinge of Fig. 4 with a variant of the spring of the snap mechanism, in three operating conditions;
Fig. 15 shows a detailed view of the spring of the hinge of Fig. 12;
Figs. 16 and 17 show the hinge of Figs. 1 and 2 with a variant of the snap mechanism, in respective operating conditions.

With reference to the above-listed drawings, reference numeral 1 designates as a whole a hinge according to the invention, which is a snap-type hinge with two articulated quadrilaterals having some elements in common.
Hinge 1 has two fastening plates 2 and 3 respectively intended to be secured (by means of screws) to a wall P and to door A of a piece of furniture such as a hanging cabinet or the like; in this case, as can be seen, plates 2 and 3 of hinge 1 are parallel to each other when the cabinet is in the closed condition, as shown in Fig. 1; on the contrary, they lie perpendicular to each other when the door is in the open condition, as shown in Fig. 2.
A bracket 4 is integral with plate 2, which bracket represents the frame or fixed side of an articulated quadrilateral that comprises two rocker arms 5 and 7 connected to each other by a connecting rod 6; the latter extends beyond the pivoting point of rocker arm 7, and its extension 8 forms one of the rocker arms of the second articulated quadrilateral of the hinge.
In fact, also the second quadrilateral comprises two rocker arms 8, 10 joined by a connecting rod 9, while a plate 3 represents the last side thereof; as can be seen, the connecting rod 9 is formed by the extension of rocker arm 7 of the first quadrilateral, and therefore the two quadrilaterals have some elements in common which connect them kinematically to each other.
In summary, the first quadrilateral comprises bracket 4, rocker arms 5, 7 and connecting rod 6, articulated at vertexes 11, 12, 13 and 14; the second quadrilateral comprises rocker arms 8, 10 and connecting rod 9, articulated at vertexes 13, 15, 16 and 17.
According to this example of the invention, at the bases of the rocker arms 5 and 7, i.e. at hinging vertexes 11, 14 of bracket 4, there are respective appendixes 18 and 19 which are perpendicular to said rocker arms.
In particular, as shown in Figs. 1 and 2, appendixes 18, 19 protrude from respective rocker arms 5 and 7 on the side towards the inside of the articulated quadrilateral; furthermore, according to the preferred embodiment shown in said figures, when the hinge is open or closed two appendixes 18, 19 are on opposite sides with respect to the horizontal line that joins vertexes 11 and 14 of the first articulated quadrilateral.
It follows therefore that the relative arrangement of appendixes 18, 19 is offset by 180°, so that, although they move jointly with a simultaneous angular rotation (i.e. the same as that of respective rocker arms 5, 7), their peripheral speeds are offset by 180° and are therefore contrary to each other.
According to the embodiment of the invention shown in Fig. 3, two levers 23, 24 articulated at appendixes 18, 19 are pivoted to each other at their connection point 22.
It should be noted that Fig. 3 refers to a transitory operating condition between those shown in Figs. 1 and 2: in this regard, it should be pointed out that in this intermediate condition appendixes 18 and 19 lie substantially in the same straight line, and the distance between one another is therefore the shortest obtainable, due to the geometry of the system.
Referring now to Figs. 4, 5 and 6, there is shown the complete snap mechanism of the hinge, i.e. including a coil spring 20 acting upon articulation point 22 of levers 23, 24; spring 20 is connected on the opposite side to a fixed pin 21 on bracket 4.
In the hinge operating conditions shown in Figs. 4 and 6, spring 20 is idle; so that during the transition from one condition to the other as the door A is being opened or closed, the spring is pulled determining the snap action of the hinge.
In this regard, it can be observed that spring 20 reaches its maximum extension in the intermediate condition shown in Fig. 5, which shows the transition between the condition of Fig. 4 and that of Fig. 6: this is due to the geometry of the system of articulated levers 23, 24, which in this condition are symmetrical with respect to the vertical, while appendixes 18, 19 are aligned horizontally.
In this intermediate condition, which can be called "dead centre", the elastic return force exerted by spring 20 is strongest and the mechanism condition is unstable, in the sense that any slight movement of hinge 1 in either direction will actuate the spring and bring door A from the closed condition to the open condition, or vice versa.
In both cases, the force exerted by the spring counters the weight of door A, which would otherwise cause it to close, thus ensuring that it remains stable in position.
In this connection, it is appropriate to point out, in proper physical terms, that the force of spring 20 is applied to articulated levers 23, 24 and is then amplified by the lever arm of the latter relative to the respective fulcrum.
In particular, levers 23, 24 allow spring 20 to extend up to the condition shown in Fig. 5, so that, all other conditions being equal, the elastic resistance generated in opposition to the door weight is higher than that of any hinges known in the art.
In other words, by increasing the extension of the spring, the elastic force exerted by the latter will be stronger (as stated by the well-known Hooke's law, according to which F = k·X, where k is the elastic constant and X is the spring deformation): therefore, this solution allows to support heavier doors by using the same springs as those currently in use, or even smaller ones.
It is also appropriate to point out that the elastic force of spring 20 actually counters the motion of the crank mechanism formed by two articulated levers 23, 24, the rocker arms 5, 7 and appendixes 18, 19, with respect to vertexes 11, 14 of the articulated quadrilateral.
Since the motion of the crank mechanism is symmetrical with respect to the aforementioned dead centre, the behavior of the opening or closing hinge will be symmetrical as well, so that it can be secured to mounting surfaces (i.e. the cabinet door or wall) which may be indifferently perpendicular or parallel to each other.
It is apparent from the above description that hinge 1 fully achieves the object of the invention.
In fact, as explained above, it allows cabinet door A to be kept stably in the open (or closed) condition by using only one spring, the elastic force of which causes a reaction against the rotation of the door; in particular, the elastic rotation is amplified by articulated levers 23, 24 and by appendixes 18, 19 in a synergic manner.
As aforementioned, this effect allows to use a single spring for keeping larger and heavier doors open; also, the spring can be a normal one, i.e. it does not need to be sized bigger in order to support the weight of the door.
There are also further advantageous aspects of the invention that need to be highlighted. For example, it should be noted that hinge 1 requires no special design measures, since no parts thereof need to be oversized to withstand excessive stresses.
This is also due to the fact that appendixes 18 and 19 are located at the base of rocker arms 5 and 7, i.e. where there are no articulations in common with the other quadrilateral; this also provides symmetry in the system, so that rocker arms 5, 7 turn out to be parallel to each other and the articulated quadrilateral becomes a parallelogram.
It follows that the behavior of the hinge according to the invention is uniform in both the opening and closing actions of the door.
This aspect allows hinge 1 to be used in the case where plates 2, 3 are secured to parallel surfaces, as in the door closed condition shown in Fig. 1, as well as in the case where they are secured to perpendicular surfaces: in fact, there is no need to use an additional spring in order to compensate for an uneven rotation of the rocker arms caused by lack of parallelism.
Of course, the invention may be subject to many variations with respect to the example taken into consideration so far.
According to a first variant, fixed pin 21 on bracket 4 is replaced with a movable pin 21', through which spring 20 is secured to the plate, as shown in Figs. 7 and 8.
These drawings clearly show that movable pin 21' is integral with a slider 39 associated with a threaded sleeve 40, which in turn is engaged by a screw 41: by acting upon the latter (e.g. with a screwdriver, as shown), the reaction on threaded sleeve 40 will move slider 39 axially in the directions indicated by the arrows, thereby moving movable pin 21' closer to or farther from articulation point 22 of levers 23 e 24.
By so doing it is possible to vary the length of spring 20 by changing its preload, thus adjusting the force it will exert on articulated levers 23, 24 adapting it to support doors with different weights.
Figs. 9 to 11 show perspective views of such variant equipped with a movable pin in three operating conditions, i.e. with the door closed, half-open (dead centre), and open, respectively.
A second variant of the hinge according to the invention is shown in Figs. 12 to 14 in three operating conditions, i.e. with the door closed, half-open, and open, respectively.
In the place of coil spring 20, which essentially operates under tension, it uses a flexing spring 27 which is visible in the enlarged frames of the respective figures and in more detail in Fig. 15; spring 27 is located substantially around articulation point 22 of levers 23, 24, with its two ends resting on the latter.
The operation principle of this hinge remains the same as the one already described; therefore, for clarity, reference should be made to the above explanation.
It should only be pointed out that, in this case as well, the operating conditions of Figs. 15 and 17 (corresponding to a closed door and an open door, respectively) are stable balance conditions, whereas the condition of Fig. 16 (corresponding to a transitory intermediate condition between the preceding two) is not stable: spring 27 counters the closing of the angle between two articulated levers 23 and 24, and generates on the articulated quadrilaterals a resistant torque that causes the above-described snap action.
From a general viewpoint, it should also be taken into account that the arrangement of articulated levers 23, 24 and of appendixes 18, 19 at the base of rocker arms 5, 7 is with no doubt to be preferred in view of the implementation of the invention, because it is simple and does not hinder the movement of the articulated quadrilaterals.
From a mechanical viewpoint, it will still be possible to mount the articulated levers at the ends of rocker arms 5, 7, i.e. at vertexes 12, 13 of the articulated quadrilateral.
In such a case, it will be necessary to provide appendixes, like appendixes 18, 19 described above, at the ends of the rocker arms; this solution is however more difficult to implement than the other one, because of the risk of interference between the articulated levers and the hinge movement.
Finally, a further variant of the hinge according to the invention does not comprise the articulated levers 23 and 24: this case is shown in Figs. 16 and 17, wherein those parts being structurally or functionally equivalent to those previously described are designated by the same reference numerals.
In practice, this hinge variant is different in that spring 20 operates directly between the appendixes 18, 19.
In this case, during the transition between the closed and open conditions (or vice versa), the spring is subject to compression and generates the snap action.
This solution offers the advantage that it can be applied to the same appendixes 18, 19 offset by 180° of the previous case, thus requiring no changes to these hinge elements.
In general, it can be stated that the variants of the invention which comprise articulated levers (i.e. those of Figs. 3-15) are more suitable for hinges wherein one of fastening plates 2 has a protruding bracket 4, like the one shown in the drawings: said bracket, in fact, lends itself to be used as a support for spring 20, as already explained.
On the contrary, the variant of Figs. 16 and 17 is more suitable for use in hinges having flat fastening plates.
Lastly, it should be mentioned that appendixes 18, 19 may however be arranged on rocker arms 8 and 10 of the other articulated quadrilateral, together with spring 20.
All of these variants will still fall within the scope of the following claims.

Claims

Snap hinge for furniture, comprising a first and a second articulated quadrilaterals, associated with respective plates (2, 3) for securing it to a wall (P) and to a door (A) of a piece of furniture, each quadrilateral comprising a pair of rocker arms (5, 7; 8, 10), one of which extends beyond the vertex (13) of the respective quadrilateral, thus forming a connecting rod (6, 9) of the other quadrilateral, characterized by also comprising a pair of articulated levers (23, 24) extending between the rocker arms (5, 7) of one of the quadrilaterals, which are subjected to the action of elastic means (20; 27) countering the rotation of the door of the piece of furniture,
wherein the rocker arms (5, 7) comprise appendixes (18, 19) from which the articulated levers (23, 24) extend.
Hinge according to claim 1, wherein the elastic means comprise a spring (20; 27).
Hinge according to claim 2, wherein the spring (20) is a coil spring and operates axially at the articulated connection point (22) of the levers (23, 24).
Hinge according to claim 3, wherein the spring (20) has one end engaged with a pin (21') or the like, the position of which can be adjusted in order to change the spring preload.
Hinge according to claim 2, wherein the spring (27) is a flexing one and acts upon both articulated levers (23, 24).
Hinge according to any of claim 3 to 5, wherein during the transition from a condition corresponding to the closed condition of the door of a piece of furniture to a condition corresponding to the open condition thereof, and vice versa, the articulated levers (23, 24) arrange themselves at an angle and determine the maximum deformation of the spring (20; 27).
Hinge according to claim 6, wherein in the condition of maximum deformation of the spring (20; 27) the appendixes (18, 19) are aligned in reciprocally opposed positions.
Hinge according to claim 1, wherein the elastic contrast means (20) comprise a spring extending between the appendixes (18, 19) protruding from the respective rocker arms (7, 8).
Hinge according to any of the preceding claims, wherein the rocker arms (5, 7) from which the appendixes (18, 19) protrude are parallel to each other, and the respective quadrilateral is an articulated parallelogram.
Hinge according to any of the preceding claims, wherein the appendixes (18, 19) are arranged at the base of the respective rocker arms (5, 7), which is articulated to the side of the respective quadrilateral integral with the wall (P) or the door (A) of the piece of furniture.