[0001] The present invention regards a support structure for surfaces, in particular for
tables with work surface with variable height.
[0002] Tables are known in which the user, according to his needs, can vary the height of
the work surface from the ground, modifying the configuration of the table legs, which
have, for example, a telescopic or tiltable structure.
[0003] The US patent
US-A-3,738,286 describes a table in which each of the four legs is pivoted on a respective lateral
face of a parallelepiped support, so that each leg can rotate around an axis perpendicular
to its longitudinal axis. On each of the four lateral faces of the support, an eccentrically
pivoted pin or block is present of circular or irregular polygonal shape, on whose
lateral faces each leg can be in abutment. Consequently, according to the configuration
of the block, each leg is positioned according to a different slope, thus also varying
the height of the surface which it supports.
[0004] A table with a device of this type can vary the height of its own surface in a limited
manner, since it is possible to adjust the tilt of the legs only according to restricted
number of positions, or at most within a defined angular interval.
[0005] Moreover, to modify the tilt of the legs and consequently the height of the surface,
one must separately act on each leg, a rather impractical operation and costly in
terms of time. It is also difficult to ensure the perfect horizontality of the supported
surface.
[0006] The main object of the invention is to provide a support structure with adjustable
height according to an unlimited number of possible configurations.
[0007] An equally important object of the invention is to provide a functional adjustment
mechanism such that with only one command, the adjustment is carried out of all legs
simultaneously.
[0008] These and other objects are achieved by an support structure with variable height
for a surface comprising at least two tiltable legs, and a support to which the at
least two legs are pivoted by means of respective pivoting elements, characterised
in that it comprises means for the controlled rotation of each pivoting element by
a desired angle.
[0009] Due to a rotation of the pivoting elements in clockwise or anticlockwise sense, the
tilt of the legs is modified, raising or lowering the work surface of the table sustained
by the support structure.
[0010] The pivoting elements are mechanically connected to each other through gears or other
transmission mechanisms (for example, belts, pulleys or levers), so that with a rotation
of a pin, there corresponds an analogous rotation of the other pins.
[0011] With a handwheel or other appropriate means, the user can drive the gears which rotate
the pivoting elements. Advantageously, the gears are conformed so as to reduce the
transmission ratio and thus diminish the force of the user to rotate the pivoting
elements.
[0012] Advantageously, it is also possible, by rotating one single leg, to tilt all of the
other legs and in this manner vary the height of the work surface. Moreover, the legs
can be tilted according to a wide (substantially infinite) number of configurations,
not limited as with the table described in
US-A-3,738,286.
[0013] The aspects and advantages of the present invention will be more evident from the
following description, given as merely exemplifying, with reference to the attached
drawings in which:
- Figure 1 is a schematic lateral view of a table according to the invention;
- Figure 2 is a top axonometric view of the tilt adjustment mechanism of the legs of
the table of Figure 1;
- Figure 3 is a bottom axonometric view of the mechanism of figure 2;
- Figure 4 is a top axonometric view of the mechanism of Figure 2, without some components
so to better illustrate its structure;
- Figure 5 is a bottom axonometric view of the mechanism of Figure 4;
- Figure 6 is a lateral view of a gear of the mechanism of figure 2.
[0014] The following description, referred to the aforesaid drawings, regards a table 10
with three legs 21, 31, 41, it being understood that the support structure can also
comprise two or more than three legs.
[0015] The table 10 according to the invention comprises a surface 12 supported by the three
legs 21, 31, 41 with perimeter of triangular form with curvilinear sides. The leg
portions corresponding to the three vertices of the triangle are respectively a support
point of the leg on the ground, a point of contact and support between leg and table,
and a connection point to a mechanism 20, illustrated in figure 1 contained within
a spherical cover. The three legs 21, 31, 41 are therefore connected to each other
by means of the mechanism 20 and are each rotatable around its own horizontal axis.
[0016] The mechanism 20, illustrated in figures 2, 3, comprises a carrier structure formed
by a disc 52 and a plate 54, parallel and connected to each other by four spacer columns
56.
[0017] On one axis 18, perpendicular and rotatable with respect to the disc 52 and to the
plate 54, a bevel gear wheel 14 and a gear wheel 70 are rigidly mounted.
[0018] The bevel gear wheel 14 engages three bevel pinions 24, 34 (in figures 2 and 4 only
two pinions are visible and indicated) whose shafts 124, 134 are rotatably mounted
on respective supports 28, 38 rigidly fixed on the face of the disc 52 turned towards
the plate 54. The three bevel pinions 24, 34 and the respective shafts have axis parallel
to the disc 52 and are arranged in rotation symmetry with respect to the axis 18 (120°
angles are formed between the shafts).
[0019] Each shaft of the three pinions 24, 34 in engaged in a respective joint 27, 37 with
adjustable tightening. In turn, a pin 36 is coupled on each joint 27, 37 (in figure
2 only one pin is visible), pin 36 coaxial with the related shaft of the pinions 24,
34 (mounted on the same joint).
[0020] Each pin is rotatably mounted on a support 29, 39 and is integral with a fixing fork
22, 32, 42 arranged outside the edge of the disc 52. Each fixing fork 22, 32, 42 stably
locks one portion (corresponding with one of three vertices) of a leg.
[0021] The shafts of the three pinions are integral by means of the joints 27, 37 to the
respective pins of the forks, so that the same forks (and related legs) are all tilted
at a same angle. Possible adjustments are possible by acting on the adjustable tightening
joints 27, 37.
[0022] Due to the above-described gear complex, the legs of the table 10 rotate simultaneously,
or rather the rotation of the bevel gear wheel 14 leads to a simultaneous rotation
of the three pinions 24, 34 and consequently of the axis of the pin of each fork 22,
32, 42 integral with the respective leg 21, 31, 41.
[0023] As is visible in the figures 4, 5, the gear wheel 70 engages a second gear wheel
170 rigidly mounted on an axis 118. The number of teeth and the diameter of the gear
wheel 170 are less than those of the gear wheel 70.
[0024] With reference to figures 3 and 5, a gear wheel 16 is mounted on the axis 118, gear
wheel 16 arranged on the face of the disc 52 opposite that turned towards the plate
54 (the disc 52 is interposed between the gear wheel 16 and the second gar wheel 170).
The number of teeth and diameter of the gear wheel 170 are less than those of the
gear wheel 16.
[0025] The gear wheel 16 engages a worm screw 62, mounted on two supports 64 fixed to the
disc 52. One end 66 of the worm screw 62 is shaped with polygonal section so to form
a male-female coupling with the bush 68 at one end of a handwheel 60 (bush with section
equal to the end 66). Instead of the male-female coupling described above, other coupling
systems known in the sector can in any case be used
[0026] By rotating the worm screw 62 with the handwheel 60, the gear wheel 16 rotates and,
since it is rigidly pivoted on the axis 118, the second gear wheel 170 also turns.
The second gear wheel 170, in turn, rotates the gear wheel 70, on which it engages,
and consequently also the bevel wheel 14 rotates, it being rigidly mounted on the
same axis 18 of the gear wheel 70. The gear wheel 14 rotates the pinions 24, 34, which,
being connected to the forks 22, 32, 42, vary the tilt of the legs 22, 32, 42 and
the height of the table 10 surface 12 from the ground
[0027] The structure of the gears (diameter and number of teeth of the gear wheel 16, of
the second gear wheel 170, of the gear wheel 70 and of the bevel wheel 14) involves
a reduction of the transmission ratio, so that the user's force for rotating the handwheel
60 is minimal.
[0028] Moreover, unless there are intentional interventions of the worm screw 62, the coupling
of the gear wheel 16 with the worm screw 62 blocks the rotation of the gears formed
by the gear wheel 14 and the position of the pinions 24, 34, maintaining the configuration
of the table 10 according to the pre-selected tilt of the legs.
[0029] The table can comprise a number of legs which is greater than 3. The same form of
the legs can be different from that of the described variant: for example, one leg
can be a simple rod, locked by the corresponding fork (or other locking means).
[0030] Moreover, the simultaneous rotation of the pins connected to the legs (and the related
tilt of the legs) can be obtained with transmission mechanisms which are different
from that described, also using belts, pulleys or gear wheels which are diversely
arranged
[0031] Analogously, variations are also possible of the mechanism driven by the user to
rotate and lock the pins connected to the legs; for example, a worm screw can be coupled
directly to a gear wheel (wheel 14 in the case of table 10) which engages the bevel
wheels connected to the pins of the legs.
[0032] According to one variant of the invention, the mechanism for tilting the legs can
comprise pinions rotating independently from each other (without mechanical interconnection).
An adjustment mechanism of the rotation of each pinion permits rotating each leg by
a different angle, so to be able to not only vary the height of the surface, but also
tilt it according to the desired configuration.
[0033] According to a further variant of the invention, the support structure can comprise
only two legs connected to each other and with adjustable tilt. At least one of the
two legs comprises a base at its abutment end with the ground, such as for example
a bar perpendicular to the leg.
[0034] A further variant of the invention provides that the support structure comprises
a single leg connected in a tiltable manner by means of the same support structure
to the surface to be supported. For example, the load-bearing structure of a table
can be an articulated parallelogram in which an oblique side corresponds to a leg
connected in an adjustable, tiltable manner with the support structure to the surface
or with the side of abutment to the ground
1. Support structure with variable height for a surface (12) comprising at least two
tiltable legs (21, 31, 41), and a support (52, 54, 56) to which the at least two legs
(21, 31, 41) are pivoted by means of respective pivoting elements, characterised in that it comprises means (14, 24, 34) for the controlled rotation of each pivoting element
by a desired angle.
2. Support structure according to claim 1, wherein the pivoting elements comprise mechanical
interconnection means (14, 24, 34), so that with a rotation of one pivoting element
there corresponds a rotation of the other pivoting elements.
3. Support structure according to claim 2, wherein each pivoting element comprises a
pinion (24, 34) with respective pin (124, 134), each pinion (24, 34) being engaged
on at least one gearwheel (14) mounted on a shaft (18).
4. Support structure according to claim 3, comprising adjustment means (16, 18, 62, 70,
118, 170) of the rotation of a pin (124, 134) of the pinions (24, 34).
5. Support structure according to claim 4, wherein the adjustment means comprise a system
of gears (16, 18, 62, 70, 118, 170) which are mechanically connected to the gear wheel
(14).
6. Support structure according to claim 5, wherein the system of gears comprises a worm
screw (62) which engages the gearwheel (14).
7. Support structure according to claim 6, wherein the gear comprises a worm screw (62)
which engages a gear wheel (16) mounted on a shaft (118) on which also a second gear
wheel (170) is rigidly mounted; the second gear wheel (170) being engaged on a gear
wheel (70) having shaft (18) in common with the gear wheel (14).
8. Support structure according to claim 7, wherein the diameter and number of teeth of
the second gear wheel (170) are less than those of the gear wheel (70) on which it
engages.
9. Support structure according to claim 7, wherein the diameter and number of teeth of
the second gear wheel (170) are less with respect to those of the gear wheel (16)
mounted on the same shaft (118).
10. Support structure according to claims 6 or 7, wherein the adjustment means comprise
a handwheel (60), which can be engaged in a removable manner on the worm screw (62).
11. Support structure according to one of the preceding claims, wherein the pins of the
pinion (24, 34) have rotation axes lying on the same plane.
12. Support structure according to one of the preceding claims, wherein the pins of the
pinions comprise fixing forks (22, 32, 42) to the legs.
13. Support structure according to claim 11, wherein the legs are of triangular form with
one vertex integral with the respective fork (22, 32, 42).
14. Support structure according to one of the preceding claims, wherein the support is
covered by a spherical cover.
15. Support structure according to one of the preceding claims, wherein the legs are at
least three.
16. Support structure with variable height comprising:
- a support for a surface,
- at least one tiltable leg connected to the support,
characterised in that it comprises means for the controlled rotation of the at least one leg with respect
to the support by a desired angle.
17. Table (10) comprising at least one support structure according to one of the preceding
claims.