"HINGE FOR DOORS"

[0001] The present invention relates to a hinge for doors, in particular glass doors.

[0002] Hinges, in particular for glass doors, according to the preamble of claim 1, are known. Such hinges are also referred to as snap hinges, since they are suitable for facilitating the positioning of the door in the stop positions, for example corresponding to open door and closed door, and the permanence of the door in said positions. In such known hinges, the cam element has a circular profile, wherein notches or grooves having a substantially semicircular shape are ^* made for stopping the cursor of the mobile part of the hinge in the stop positions. In known hinges of this type, the cursor is shaped as a piston stressed by one or more springs to cooperate with the cam element.

[0003] Figure 8 is a graph showing the pattern of the cursor stroke depending on the rotation angle of the door between 0° and 90°. In the example shown, in the starting position, corresponding to an angle of 0°, the cursor is at a distance of 16 mm from the wall on which the spring element rests, taken as a reference for the cursor stroke.

[0004] As can be seen, the cursor withdraws with a substantially linear motion up to a position of about 11 mm in about the first 30° of door rotation, an angle which causes the exit of the cursor from the first notch. For about the next 40°, i.e. up to about 70°, the cursor stroke remains substantially constant. After 70°, the cursor enters in the second notch and its stroke then increases again.

[0005] Therefore, from about 20° to about 70° the cursor of traditional hinges does not undergo any variation in the stroke, i.e. the door is not decelerated and is subject to the maximum resistance strength by the given spring compression. In this way, the hinge components are always subject to maximum stress in the steps where the door is mostly used, i.e. during the opening between about 20° and 55° .

[0006] In other embodiments, for example described in EP1772578A1 and in DE102005039445A1, the cursor undergoes a substantially linear stroke variation up to an angle of about 70°. In this case, the spring offers an increasing resistance to the door opening, to the detriment of comfort in the door opening step.

[0007] Moreover, when the springs work in high compression conditions, they react violently and instantaneously if the load applied thereon fails, so the door could violently return on the person that is opening it if the opening is not completed and if the person, upon the end of the thrust action, is not swift to move away from the range of action of the door.

[0008] Moreover, the use of the springs does not allow the vibrations to be absorbed or the mobile system to be decelerated in the stopping steps. If the door is moved with a certain acceleration, therefore, the stop may occur after some oscillations.

[0009] Summarising, known hinges have the following limitations or drawbacks:

[0010] - collision of the mobile part in the closed or locked positions;

[0011] - uncontrolled door speed in the opening and/or closing steps or, on the contrary, high resistance in the opening step and thereby, poor comfort;

[0012] - vibrations;

[0013] - need for the springs to be provided with a spring lubrication system for reducing noise and preventing oxidation.

[0014] Especially in the case of glass doors, such drawbacks cause:

[0015] - lower safety of glass doors;

[0016] - presence of noise;

[0017] - possible leaks of oil or grease from the hinge;

[0018] - inability to use 'the hinge in wet environments (such as in bathrooms) ;

[0019] - use of a large number of components for ensuring the correct operation of the spring system;

[0020] - high production costs;

[0021] - linear and constant resistant force not depending on the rotation speed of the door.

[0022] The object of the present invention is to propose a hinge, in particular for glass doors, capable of obviating the drawbacks mentioned above with reference to traditional snap hinges.

[0023] Said object is achieved with a hinge according to claim 1 . The dependent claims describe preferred embodiments of the invention.

[0024] The features and the advantages of the hinge according to the invention will in any case appear more clearly from the following description of preferred embodiments thereof, given by way of a non-limiting example with reference to the accompanying drawings, in which :

[0025] - figure 1 shows an exploded perspective view of the hinge according to the invention;

[0026] - figure 2 shows a perspective view of the assembled hinge;

[0027] - ^" figure 2a shows a view similar to the previous one, with a portion of the mobile part of the hinge removed;

[0028] - figure 3 shows an elevation view of the hinge;

[0029] - figure 4 shows a cross section of the hinge according to line A-A.in figure 3;

[0030] - figure 5 shows an axial section of the hinge;

[0031] - figure 6 shows the hinge applied to a door;

[0032] - figures 7-7e show cross section views of the hinge in as many steps of its rotation between a closed position and an open position;

[0033] - figure 8 shows a graph showing the pattern of the cursor stroke depending on the rotation angle of the door between 0° and 90°, in a hinge according to the prior art; and

[0034] - figure 9 shows a graph similar to the previous one but referred to the hinge according to the invention.

[0035] In said drawings, reference numeral 1 globally indicates a hinge for doors according to the invention. Hinge 1 comprises a fixed part 10, suitable for being attached to a jamb 100 of a door 120, and a mobile part 12, suitable for being attached to door 120, for example consisting of a glass sheet. The mobile part 12 is hinged to the fixed part 10 in such a way as to rotate, for example by an angle substantially equal to 90°, between a first stop position, for example corresponding to closed door, and a ^' second stop position, for example corresponding to open door.

[0036] The fixed part 10 comprises a cam element 14. For example, said cam element 14 is seated in a recess 16 made in body 10' of the fixed part 10 and open towards the mobile part 12. Body 10' of the fixed part 10 is crossed by a pin hole 18 wherein a rotation pin 20 is inserted for rotating the mobile part 12 relative to the fixed part 10. In a preferred embodiment, said rotation pin 20 also crosses the cam element 14.

[0037] At least a first notch 22 and a second notch 24 are made in said cam element 14. Said notches 22, 24 define said first and second stop positions of the door. Said first and second notches 22, 24 are separated by an intermediate sliding surface 26.

[0038] Therefore, in one embodiment, the first and the second notches 22, 24 are angularly spaced from each other by an angle equal to 90°.

[0039] According to an embodiment which allows the door to be opened in both directions relative to the closed position, the cam element 14 has a symmetrical profile relative to the axis which passes by the first notch 22 and by the rotation pin 20. In other words, the cam element 14 has a third notch 24', diametrically opposite to the second notch 24 relative to the rotation pin 18, suitable for determining a third stop position of the door, i.e. an opening position in a direction opposite to the second stop position.

[0040] In one embodiment, the cam element 14 comprises, for example on the diametrically opposite side relative to the first notch 22, a tang 141 inserted in a respective tang seat 142 made in body 10' of the fixed part 10 and locked to said body 10' , for example by means of a pair of opposite side dowels 143 which also allow the cam element 14 to be optionally oriented to a certain angle relative to the vertical symmetry plane of body 10' of the fixed part 10.

[0041] The mobile part 12 comprises a radial control cursor 28 of the rotation of the door. Said radial cursor 28 is elastically influenced to slide along the cam element 14 subsequent to the rotation of door 120 and is suitable for inserting itself in said first and second notches 22, 24 so as to stop the door in said first and second stop positions. During its sliding along the profile of the cam element 14, the radial cursor 28 moves by a rectilinear motion relative to the mobile part of the hinge seating it. Hereinafter, the shifting of said radial cursor 28 is defined as "radial stroke" (to differentiate it from the angular stroke about the cam element 14), or more shortly, "stroke".

[0042] Considering hinge 1 in the vertical assembly position, as shown in figure 6, in one embodiment the mobile part 12 is shaped as a "C", so as to surround the fixed part 10. That is, the mobile part 12 comprises an upper horizontal portion 121 and a lower horizontal portion 122 which are at least partly crossed by the rotation pin 20.

[0043] The mobile part 12 further comprises a central portion 124 wherein a cursor seat 126 is made wherein the radial cursor 28 and a spring means 30 are seated, which spring means keeps cursor 126 pressed against the cam element 14.

[0044] In one embodiment, the radial cursor 28 is shaped as a piston with a contact head 32 with the cam element 14 of a spherical or cylindrical shape. Notches 22, 24 of the cam element 14 have a shape complementary to said head 32, i.e. as a spherical cap or cylindrical surface.

[0045] The spring means 30 is interposed between the radial cursor 28 and a bottom wall 128 of the cursor seat 26.

[0046] According to one aspect of the invention, said spring means 30 is shaped as a block of a damper material, i.e. suitable for absorbing the loads it is subject to. In one embodiment, said material is a visco- elastic material, for example an elastomer in mixed cell polyurethane . In one embodiment, said damper material is marketed by the company Ace Controls International with the trade name of SLAB.

[0047] Such block, which is normally used as a shock absorption mat, is used herein both with the function of spring element for the door return and with the function of decelerator.

[0048] Moreover , the block of damper material has the feature of reacting with a different strength depending on the speed and/or acceleration of the impact, unlike mechanical springs which, upon an equal displacement, always react with the same strength.

[0049] In one embodiment, the central portion 124 of the mobile part is interposed between two fixing plates 130 which retain door 120, in particular a glass sheet, thereinbetween .

[0050] According to one aspect of the invention, the concavity of said first and second notches 22, 24 and the profile of said intermediate sliding surface 26 are chosen in such a way that the radial stroke of the radial cursor 28 depending on the rotation of the mobile part 12 starting from the first stop position:

[0051] - undergoes a first reduction until it reaches a first angle corresponding to the exit of the radial cursor 28 from the first notch 22;

[0052] - undergoes a second reduction, of a smaller entity than the first, until it reaches a second, angle along the intermediate sliding surface 26;

[0053] - undergoes a third reduction, of a greater entity than the second, until it reaches a third angle corresponding to the positioning of the radial cursor on the proximal edge which delimits the second notch 24; and [0054] - undergoes an increase following the insertion of the radial cursor 28 in the second notch 24.

[0055] Considering the overall rotation of the mobile part 12 of the hinge equal to about 90°, in a preferred embodiment the profile of the cam element 14 is chosen in such a way that said first angle is from 15° to 25°, the second angle is from 45° to 55°, and the third angle is from 65° to 75° .

[0056] According to a preferred embodiment, such pattern of the stroke of the radial cursor 28 between the first angle and the third angle is obtained by making the intermediate sliding surface 26 as a flat surface. In particular, the distance between the first notch 22 and the rotation pin 18 is less than the distance between the second notch 24 'and said rotation pin 20.

[0057] With reference to the graph ^' of figure 9, wherein an initial stroke of 16 mm of the radial cursor 28 is indicated by way of an example only, i.e. the distance between the radial cursor 28 and the bottom wall 128 of the cursor seat 126 when the mobile part 12 of the hinge is in the first stop position (figure 7), it is noted that until the first angle (about 20°) is reached, i.e. until the head of the radial cursor exits from the first notch, the radial cursor 28 gradually withdraws, carrying out a stroke of about 3 mm (versus the about 5 mm of a similar traditional hinge) (figure 7a) . In this first step, therefore, through the spring means 30 which is compressed by the radial cursor, the hinge offers a suitable resistance to the displacement from the first stop position.

[0058] Between the first angle and the second angle (about 50°), the radial cursor 28 undergoes a more restrained stroke variation, for example of about 1 mm. In this second step, therefore, the hinge offers a lower resistance to the displacement (figures 7b and 7c) .

[0059] Between the second angle and the third angle (about 65-70°), there is again an increase in the slope of the stroke curve, given by a travel of more than 1 mm in about 20° rotation (figures 7d, 7e) . In this third step of the rotation, the compression of the spring means 30, in particular in the case of the block of damper material, allows an absorption of the door acceleration, thanks to which the door is prevented from slamming in open position or the door is allowed to automatically return to the closed position (i.e. 0°). [0060] Over 70°, the cursor head inserts itself in the second notch 24 of the cam element and therefore, a reversal of the cursor stroke occurs which increases, thus favouring the door stop in the second stop position (about 90°) .

[0061] Therefore, the hinge according to the invention allows the door to be stopped in the closed position, preventing the undesired opening thereof, for example under the action of the wind. In particular, the door is automatically closed after the opening. The opening (or closing) of the door is dampened thanks to the absorption of the door acceleration provided by the compression of the block of damper material, during the third opening step.

[0062] Note the particular synergic effect given by the combination of the particular profile of the cam described above with the use of block 30 of damper material. In particular in the second step, i.e. between the first and the second angle, the stroke variation of the radial cursor 28 is very limited and the compression of block 30 remains at an intermediate level, i.e. it .is lower than the maximum compression that occurs in the third step, although sufficient to cause a return of the door to the closed position. In these conditions, the door is opened without offering a great resistance and the user perceives the feeling of a virtually free movement. On the one hand, this greatly improves the comfort in the door opening step, as compared to the prior art hinges, which in this step oppose a much higher resistance. On the other hand, this poor resistance of the hinge allows the door to be opened with a certain speed and/or acceleration. The use of block 30. in place of one or more traditional springs, in the subsequent third step wherein the stroke variation of the radial cursor 28 increases again, allows the absorption of the kinetic energy of the door and thus the achieving of the fully opened position of the door without collisions or oscillations, or the return to the closed position in a gentle and controlled manner.- [0063] In particular, during the third opening step of the door, block 30 therefore has the function of decelerator.

[0064] A mechanical spring in place of the block of damper material would still provide the same response also in case of high speeds and/or accelerations of the door in the closing step and, since it has no absorption action of the kinetic energy of the door, it would not be able to decelerate the door itself close to the closed position, causing dangerous oscillations or collisions.

[0065] The damper effect of block 30 also implies a reduction of vibrations and noise. Finally, the use of the damper material in place of a spring allows the lubrication to be avoided, the hinge to also be used in wet environments, the hinge components and thereby, also the production and assembly costs to be reduced.

[0066] A man skilled in the art may make several changes, adjustments and replacements of elements with other functionally equivalent ones to the embodiments of the hinge according to the invention in order to meet incidental needs, without departing from the scope of the following claims. Each of the features described as belonging to a possible embodiment can be obtained independently of the other embodiments described.