Joint device and table comprising that device

Abstract

 A four-bar linkage joint device (10) for pivotably connecting two structures comprises an additional rod for keeping aligned the two main rods (13,14) of said four-bar linkage in order to prevent fortuitous movements of the joint when it is in its open configuration. Release means favourably arranged allows misaligning the rods for closing the joint device. A table, in particular for campers or camping provides foldable legs which can be closed under the table top thanks to joint devices according to the invention which pivotably connect the legs to the top.

Description

TECHNICAL FIELD

[0001] The present invention concerns a four-bar linkage device for connecting two structures which have to mutually rotate of an angle of about 90°.

[0002] The invention also concerns a table, in particular for campers or camping, with legs hinged to the table top and foldable under the table top by a four-bar linkage.

STATE OF THE ART

[0003] Tables are known, in particular camping or camper tables, in which the legs can be folded under the table top to reduce the table overall dimensions when not in use.

[0004] In this kind of tables the legs are often connected to the top by four-bar linkages. Practically the legs are hinged to the top and the maximum rotation angle is determined by two more rods, which also give steadiness to the table, hinged together and also hinged to the table top and to the leg. The table top, the leg and the above rods form a four-bar linkage that, when between the top and the leg there is a certain open configuration angle, become a triangle since the above rods form an angle of 180°. In such configuration the angle between the top and the leg is maximum since the opposite ends hinge points of the rods cannot be set further apart, and it is also a stable configuration since the rods, which are subject only to compression, do not change their mutual angle as not torque applies to the hinge joint connecting them, so that also rotation of the legs is prevented. Obviously, such equilibrium condition with the rods aligned is unstable and an excessive load could bend the rods causing them to mutually rotate.

[0005] To prevent the rods from taking a position in which the angle between them is greater than 180° they are usually partially overlapping so that the end of one rod abuts the end of the other one.

[0006] When the table has to be closed it is needed to exert a force on at least one rod for misaligning them, and then the table can be closed by acting on the legs for folding them.

[0007] The use of a simple four-bar linkage, though it is cheap due to its simple structure, has, as above underlined, evident limits concerning the stability of the open configuration. In fact, if the alignment of the rods is accidentally lost, the legs are free to rotate, for instance under the weight of the top.

[0008] As it would be clear, the use in camper or camping tables is just one of the possible utilizations of four-bar linkage systems in which, anyway, they have the same advantages and limits.

SUMMARY OF THE INVENTION

[0009] Object of the present invention is to propose a four-bar linkage for pivotably connecting two structures in which the maximum open configuration is very safely kept.

[0010] Further object of the invention is to propose a four-bar linkage with the above features which can be disengaged from the open configuration in a very simple and easy way.

[0011] Another object of the present invention is to propose a linkage for pivotably connecting structures that need to assume a very stable open configuration with the linkage that has a simple structure and low costs.

[0012] Another object of the present invention is to propose a table, in particular a camper or camping table, with foldable legs in which the open configuration is stably and safely kept.

[0013] Another object of the present invention is to propose a table with the above features which can be disengaged from the open configuration in a very simple and easy way.

[0014] The above object are attained through a four-bar linkage joint device for pivotably connecting structures comprising a first supporting bar, a second supporting bar, a first rod and a second rod, said members being connected each other so that they form a four-bar linkage wherein said bars are adjacent members of said four-bar linkage apt to be bound to said structures to be pivotably connected, and wherein the total amounts of the lengths of the members being said supporting bars is on a ratio with the total amount of the lengths of the members of said four-bar linkage being said rods so that when said supporting bars form between them a given maximum angle said rods form between them an angle of about 180°, characterized in that it comprises a third rod hinged to said first rod and further bound to said first supporting bar by a roller bearing constraint apt to allow pivoting around the constraint point and sliding of the constraint point along said first supporting bar, the distance and position of the constraint points of said third rod being such that, when said first and second rods are aligned forming between them an angle substantially of 180°, said third rod is positioned substantially perpendicular to the direction of sliding of its roller bearing constraint.

[0015] Then angle between the first and second rods can be at most 180° due to one rod that abuts the other. When the two rods form the angle of 180° so that they are aligned the mutual rotation of the two supporting bars is prevented and for disengaging the mechanism it is needed to misalign the two rods. With the joint of the present invention this last is prevented by the third rod which avoid fortuitous misalignment of the first and second rods and then also the mutual rotation of the supporting bars until it keeps its position substantially perpendicular to the direction of sliding of its roller bearing constraint.

[0016] In particular, said roller bearing constraint is composed of a slide member sliding along said first supporting bar and the third rod is hinged to it. Release means integral to the slide member are apt to slide it along said first supporting bar in order to move the third rod from its equilibrium state and to consequently also misalign the first and second rods.

[0017] Still advantageously elastic means are provided acting between the slide member and the first supporting bar for keeping the slide member in the position in which the third rod is substantially perpendicular to the direction of sliding of the slide member.

[0018] The above described joint device can be coupled to a mirrored further joint device according to the present invention, integral to the first joint device through the second supporting bar which is a common member of both the joint devices.

[0019] The above objects are also attained through a table, in particular for campers or camping, in which the legs are hinged to the top of the table so that they are foldable under the top, and the table comprises a joint device as above described for connecting the legs to the top in which, in particular, the first supporting bar is integral to, or it is itself, a leg of the table, and the second supporting bar is integral to, or it is itself, the top of the table.

[0020] The advantages of a joint device or a table according to the invention are clear in view of the stable mutual position of the two hinged members connected by the joint device, that is, in a table, the legs and the top. In fact the third rod prevents the fortuitous misalignment of the first and second rods.

[0021] In addiction, the release means, which can be arranged in a safe but easily reachable position, allows disengaging the mechanism in a very simple way so that, in case of a table, the legs can be promptly folded under the table top.

BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and more advantages of the present invention will be better understood by way of embodiment examples, that will be described in the followings with reference to the accompanying drawings, in which:

• figure 1 shows a perspective view of a joint device according to the invention;
• figure 2 shows the kinematic scheme of joint device according to the invention;
• figure 3 shows a perspective view of a table according to the invention with legs in open configuration;
• figure 4 shows a perspective view of the table of fig. 3 in a configuration in which the legs are folded under the table top.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0023] With reference to fig. 1 it pointed as a whole with 10 a joint device according to the invention comprising a first supporting bar, 11, a second supporting bar, 12, a first rod, 13 and a second rod, 14.

[0024] The four above members are mutually connected by hinge means, 15, 16, 18, 19 so that they form a four-bar mechanism in which, as shown in figure, when the first supporting bar forms an angle of about 90° with the second supporting bar, the two rods are substantially aligned, that is they form an angle of 180°.

[0025] The first supporting bar and the second support bar comprise holes, 20, for connecting, for instance by screw means, respective structures that must be pivotably connected each other by the joint device 10 and that have to mutually rotate about the hinge means 15.

[0026] The first and second rod are partially overlapped so that abutting surfaces, 21, are provided for preventing the two members from forming an angle greater than 180°. In this way from the aligned configuration the angle between the two members can only decrease, bringing the hinge means 18 closer to the hinge means 15.

[0027] A third rod, 22, is bound at one end, by hinge means, 23, to the first rod 13, and at its other end, by a further hinge means, 24, to a slide member, 25, longitudinally sliding along the first supporting bar 11.

[0028] At the lower end of the slide member 25 constrained between the surface of the first supporting bar 11 and the hinge means 19, there are release means, 26, composed of an "L" shaped protuberance that can be handled for moving the slide member along the first supporting bar.

[0029] At its upper end the slide member is connected to the first supporting bar by hinge means, 27, for biasing the slide member upwards in the represented position.

[0030] With reference to fig.2 the joint device form a kinematic mechanism with one degree of freedom whose way of working can be easily understood.

[0031] The position of fig.1 corresponds to the one shown with solid line in fig.2 and it represents the maximum open angle between the first supporting bar 11 and the second supporting bar 12 as being the two rods 13 and 14 aligned the hing means 16 and 19 are prevented from further being spaced. In addiction, In such position the angle between the two supporting bars cannot be modified by directly acting on them as to do that the angle between rods 13 and 14 has to be previously decreased. Nevertheless, thanks to the rod 22, perpendicular to the direction of sliding of the slide member 25 and than in its equilibrium position, it is not possible to perform the disengaging by directly acting on the rods 13 and 14 and the slide member has to be previously moved in order to move the rod 22 away its equilibrium position.

[0032] By downward translating the slide member 25 the third rod is moved from its equilibrium position and the first rod 13 is rotated so decreasing the angle between the first rod 13 itself and the first supporting bar 11 and the angle between the first and second rods 13 and 14. Once moved the mechanism from its equilibrium position, for instance reaching the position shown in fig.2 with dash line, the joint device can also be rotated by directly acting on the supporting bars 11 and 12, up to close the supporting bar 11 on the supporting bar 12, with the other rods 13, 14 and 22 comprised between the two supporting bars. In the closed position the joint device is comprised within the overall dimensions of the first supporting bar 11, that is, exactly, with a length and width defined by the size of the first supporting bar flat surface, 28, and thickness defined by the height of its side walls, 29.

[0033] In fig. 3 is shown a table, 30 , comprising a table top, 31, and two supporting structures, 32 and 33, centrally placed close to opposite ends of the top and each comprising two legs, 34, and a legs connecting plate, 35.

[0034] The supporting structures 32 and 33 are hinged to the top 31 by joint devices 10 in which the first supporting bar 11 is integral to the plate 35 and the second supporting bar 12 is integral to the top 31.

[0035] When the table is open, with the supporting structures 32 and 33 substantially perpendicular to the top 31 the joint devices 10 are in the open position of fig. 1, so that the legs are prevented from being folded even if the rods 13 are accidentally hit.

[0036] By downward pulling the release means 26 the rods 13 and 14 are misaligned and it become possible to fold the legs 34 under the top 31 in the table closed configuration shown in fig. 4.

[0037] It has to be noted that the release means 26 can be easily reached but at the same time they are in a position in which fortuitous pulling is prevented. In addiction, the position and the way of operating the release means is much safer for the user with respect to the conventional four-bar linkages where the user has to directly push the rods 13 and 14 with the risk of having his fingers injured by the members of the four-bar linkage.

[0038] The closed configuration can be firmly kept by providing conventional rest means acting between the two supporting structures 32 and 33 or between the supporting structures and the top 31. In addiction, as shown in figure, in the closed configuration the table has minimum overall dimensions and it can be comfortably transported for instance through a handle, 36.

[0039] Obviously, changes or modification could be carried out to what above disclosed.

[0040] For instance, in a table according to the invention the legs 34 could be directly hinged to the top 31. In this case the rod 14 can be directly hinged to the top and the rod 13 could be directly hinged to the legs 34 with the sliding member to which is hinged the rod 22 moving along the legs themselves.

[0041] Alternatively, stiffening bars could be integral to the top and the second supporting bar 12 of the joint device could be bound to a stiffening bar.

[0042] The number of foldable legs and joint devices according to the invention could be from 1 to 4 or even more as a function of specific needs and number of legs. For instance, tables for campers one edge of the table top could be directly hinged to a camper wall and close to the opposite edge a single foldable leg comprising the joint device of the invention could be provided. In a different embodiment, in case the table has two joint device of the invention, for instance as shown in fig.3, they could be integral one to the other, placed mirroring each other, and connected by the second supporting bar which is a common member of both the joint devices. They could also be pre-assembled using auxiliary structures before being connected to the table top.

[0043] The joint device itself could be changed or modified with respect to what above disclosed.

[0044] The supporting bars, the rods and the hinge means could be differently shaped and dimensioned from the members shown in fig. 1, remaining unchanged their function of providing a kinematic mechanism as shown in fig. 2.

[0045] The elastic means 27 could be of a different type, they could be bound to the connected members in a different way, or they could also be replaced by different means adapted to define the position of the slide member 25 along the first supporting bar 11.

[0046] The release means 26 could be placed at any position suitable for causing the slide member 25 to slide, and they could also be motorized for instance by using a solenoid able to pull downwards the slide member. They could also be completely removed as the joint device can be moved from the position of fig. 1 also by directly acting upon the third rod 22.

[0047] The maximum open angle between the first supporting bar 11 and the second supporting bar 12 could be very different from the angle of 90° shown in figures, and it could be both lower and greater, the angle being determined by the length of the rods 13 and 14 and by the position of the hinge means 16 and 19.

[0048] Finally, many other changes could be carried out to the four-bar joint device of the invention and/or to the table comprising foldable legs of the invention remaining within the ambit of protection defined by the following claims.

[0049] In fact, the above disclosure of specific embodiments is useful to understand the field and scope of the present invention, so that people skilled in the art is able to put it into practice by modifying and adapting the above disclosed embodiments; such modifications will be then considered as equivalent of the disclosed embodiments. The numbers and terminology used are to be intended merely for disclosure and for comprehending the scope of the invention and then they do not limit the invention.

Claims

1. Four-bar linkage joint device (10) for pivotably connecting two structures, said joint device comprising a first supporting bar (11), a second supporting bar (12), a first rod (13) and a second rod (14), said members being connected each other so that they compose a four-bar linkage wherein said supporting bars (11, 12) are adjacent members of said four-bar linkage and wherein the total amounts of the lengths of the members being said supporting bars (11, 12) is on a ratio with the total amount of the lengths of the members of said four-bar linkage being said rods (13, 14) so that when said supporting bars (11, 12) form between them a given maximum angle said rods (13, 14) form between them an angle of about 180°, characterized in that it comprises a third rod (22) hinged to said first rod (13) and further bound to said first supporting bar (11) by a roller bearing constraint apt to allow pivoting around the constraint point and sliding of the constraint point along said first supporting bar (11), the distance and position of the constraint points of said third rod (22) being such that, when said first and second rods (13, 14) are aligned forming between them an angle of about 180°, the axis connecting the constraint points of said third rod (22) is substantially perpendicular to the direction of sliding of said roller bearing constraint.

2. Joint device (10) according to claim 1 characterized in that it comprises release means connected to said third rod (22) apt to move away the axis connecting the constraint points of said third rod (22) from said position substantially perpendicular to the direction of sliding of said roller bearing constraint.

3. Joint device (10) according to the previous claim characterized in that said roller bearing constraint comprises a slide member (25) longitudinally sliding along said first supporting bar (11), said third rod (22) being hinged to said slide member (25), said release means (26) being integral to said slide member (25) and apt to slide it along said first supporting bar (11).

4. Joint device (10) according to the previous claim characterized in that it comprises elastic means (27) acting between said slide member (25) and said first supporting bar (11).

5. Joint device (10) according to one of the previous claims characterized in that it is coupled with a mirrored second joint device (10) according to one of the previous claims, integral to the first joint device through said second supporting bar (12) which is a common member of both the joint devices.

6. Table (30), in particular for campers or camping, comprising at least one leg (34) hinged to a top (31) of said table so that it is foldable under said top, a first rod (13) and a second rod (14) hinged together, to said leg (34) and to said top (31) so that said members form a four-bar linkage wherein said leg (34) and said top (31) are adjacent members of said four-bar linkage and wherein the total amounts of the lengths of the members being said leg (34) and said top (31) is on a ratio with the total amount of the lengths of the members of said four-bar linkage being said rods (13, 14) so that when said leg (34) and said top (31) form between them a given maximum angle said rods (13, 14) form between them an angle of about 180°, characterized in that it comprises a third rod (22) hinged to said first rod (13) and further bound to said leg (34) by a roller bearing constraint apt to allow pivoting around the constraint point and sliding of the constraint point along said leg (34) , the distance and position of the constraint points of said third rod (22) being such that, when said first and second rods (13, 14) are aligned forming between them an angle of about 180°, the axis connecting the constraint points of said third rod (22) is substantially perpendicular to the direction of sliding of said roller bearing constraint.

7. Table (30) according to the previous claim characterized in that it comprises release means connected to said third rod (22) apt to move away the axis connecting the constraint points of said third rod (22) from said position substantially perpendicular to the direction of sliding of said roller bearing constraint.

8. Table (30) according to the previous claim characterized in that said roller bearing constraint comprises a slide member (25) longitudinally sliding along said leg (34), said third rod (22) being hinged to said slide member (25), said release means (26) being integral to said slide member (25) and apt to slide it along said leg (34).

9. Table (30) according to the previous claim characterized in that it comprises elastic means (27) acting between said slide member (25) and said leg (34).

10. Table (30) according to one of claims 6 to 9 characterized in that said legs (34) foldable under the top (31) of said table are at least two, pre-assembled together and to joint devices (10) according to one of claims 1 to 5 thanks to an auxiliary frame and bound to the plane (31) of said table (30) by said auxiliary frame.

Drawing