CHAIR WITH VARIABLE PITCH

Abstract: The invention produces a chair (1; 100) with variable pitch that includes: a frame (2; 200) set to rest on the floor; at least one central element (4) that creates a substantially horizontal longitudinal axis (X), supported by the frame (2; 200); a seat (5) supported by the central element (4); one pair of first stiles (3c) parallel to each other and set at the ends of the central element (4); a backrest (6) that has its top (6a) connected to the first stiles (3c) through first flexible couplings (7) and its bottom (6b) connected to the seat (5) through a second flexible coupling (8). The seat (5) is connected to the central element (4) through swivel means (10) that allow the planar rotary-transverse movement of the seat (5), combined with a rotary rocking movement of the backrest (6) around a longitudinal axis (Y) created by the flexible couplings (7).

Description: CHAIR WITH VARIABLE PITCH The invention concerns a chair designed to take on variable pitches or attitudes under the push exerted on the seat and on the backrest by the seated person. The market offers several types of chairs that have a variable pitch obtained by exploiting the flexing deformability of the structure making up the seat or backrest, or otherwise in some cases, fitting flexible parts between the structural components of the chair itself. The pressure that the seated person exerts on the seat or on the backrest, or on both together, modifies the pitch of the chair permitting to change the seating position as desired. It is common knowledge that by frequently changing from a leaning forward position to stretching backwards, the user tends to rub against the surface of the seat with inevitable inconveniences and discomfort. What's more the most natural positions that the user tends to assume are often limited by the sole intrinsic flexing deformability of the components that make up the chair without any possibility of adjustment. With the scope of eliminating these inconveniences, the same depositee of this patent has also registered the patent numbered VI97A000183 which describes a chair with variable pitch that allows the seated person to change from a leaning forward position to more or less stretching backwards by simply pushing on the seat or on the backrest or both together, without having to rub on the surface of the seat. What's more the range in variation of pitch can be modified by regulating special adjustments. However, even the chair with variable pitch described in the aforementioned patent has the inconvenience of only permitting the seat to perform forward or backward linear movements. This invention intends to overcome this limitation. In particular, the scope of this invention is to produce a chair with variable pitch that allows greater degrees of freedom in the seat's movement. Said scope is achieved by producing a chair with variable pitch that in accordance with the main claim includes: - a frame set to rest on the floor; - at least one central element that creates a substantially horizontal longitudinal axis X, supported by said frame; - a seat supported by said central element; - one pair of first stiles parallel to each other and set at the ends of said central element; - a backrest that has its top connected to each of said first stiles through first flexible couplings and its bottom connected to said seat through at least one second flexible coupling, it is characterised in that said seat is connected to said central element through swivel means designed to allow a planar rotary-transverse movement of said seat combined with a rotary rocking movement of said backrest around a longitudinal axis created by said first flexible couplings. According to a preferred form of execution the frame is made up of one pair of front legs connected to the ends of the central element as a continuation of the first stiles and at least one pair of back legs parallel to each other and also each being connected to one of the ends of the same central element. According to a variant in execution the frame consists of a single, substantially upright supporting body that has its top connected to said central element and its bottom provided with a floor standing structure. According to both of said forms of execution, each of the swivel means that allow a rotary-transverse movement of the seat include a first swivel element fixed to the seat and a second swivel element that slides over the central element along the latter's longitudinal axis. The swivel elements are connected together through flexible couplings and have contact surfaces that touch together. By a combination of the reciprocal sliding movement of the contact surfaces over each other in combination with the longitudinal movement of the swivel elements around the central element, a planar rotary-transverse movement of the seat is generated parallel to the level on which the seat rests when in its idle position. The aforesaid scopes shall be better illustrated in the description of a preferred form of execution of the chair invention that is described below and that refers to the attached diagrams, where: - fig. 1 shows an isometric drawing of the chair invention; - fig. 2 illustrates a blown-up isometric view of the central element of the chair in fig. 1 ; - fig. 3 illustrates the front view of the assembled central element in fig. 2; - fig. 4 illustrates a blown-up isometric view of the chair in fig. 1 without its backrest and seat; - fig. 5 illustrates the elements shown in fig. 4 assembled together; - fig. 6 illustrates a blown-up isometric view of the backrest and seat of the chair in fig. 1 ; - fig. 7 illustrates a blown-up view of the first flexible coupling that connects the backrest to its respective first stile; - fig. 8 illustrates a blown-up isometric view of the second flexible coupling that connects the seat to the backrest; - fig. 9 illustrates a view of one of the chair's swivel elements shown in its idle position; - fig. 10 illustrates another view of the swivel element in fig. 9; - fig. 11 illustrates the swivel element in fig. 10 partially sectioned and when in use; - fig. 12 illustrates a view of one of the details that make up the swivel element in fig. 9; - fig. 13 illustrates another view of the detail in fig. 12; - fig. 14 illustrates a cross-section of the detail in fig. 13; - fig. 15 illustrates a longitudinal section of the detail in fig. 12; - fig. 16 illustrates an aerial view of the detail in fig. 12; - fig. 17 illustrates the chair in fig. 1 where a dotted line shows one of the possible positions the seat and backrest may assume while varying pitch; - fig. 18 illustrates a side view of the chair in fig. 17; - fig. 19 illustrates an aerial view of the chair in fig. 17; - fig. 20 illustrates a variant in execution of the chair invention. As can be seen in fig. 1 the chair invention, generally indicated by 1 , includes a frame, generally indicated by 2, consisting of one pair of front legs 3a and one pair of back legs 3b, which rest on the floor and their ends are connected to a central element, generally indicated by 4 and creating a substantially horizontal longitudinal axis X, which supports the seat 5. As a continuation of said front legs 3a there are as many first stiles 3c, also connected to the ends of the central shaft 4, preferably but not necessarily as one with said front legs 3a with which they therefore make a single, linear body. A backrest 6 has its top 6a connected to the first stiles 3c through one pair of first flexible couplings each generally indicated by 7 and creating a longitudinal axis Y around which the backrest rotates, while a second flexible coupling, generally indicated by 8, connects the bottom 6b of the backrest 6 to the back 5a of the seat 5. In this way said seat 5 and said backrest 6 are solidly and flexibly connected together. As a preference, to make the seat more comfortable, the longitudinal axis Y of the first flexible couplings 7 is parallel to the longitudinal axis X of the central element 4. With regards to each first flexible coupling 7 that can be seen in detail in fig. 7, it includes a clamp 9 made up of two halfrings 9a that together create a seating 9b designed to receive its respective first stile 3c and a pliable body 9c coupled to one of the halfrings 9a. A threaded hole 9d made in the pliable body 9c, receives first union means consisting of one pair of screws 9e and 9f, designed to connect the elements together and to the backrest 6. Preferably, as can be seen, a washer 9g is inserted. With regards to the second flexible coupling 8 that can be seen with more detail in fig. 8, it includes a substantially cylindrical element 8a, which can be flexed out of shape, that has a threaded hole 8b through its whole length. It is designed to receive second union means consisting of screws 8c and 8d that allow it to be fixed between the back 5a of the seat 5 and the bottom 6a of the backrest 6. The assembly preferably includes washers 8e and 8f. It is clear that in different forms of execution said first union means and said second union means, instead of being screws and internal threads, they may be other forms of union. What's more these union means may also have washers. Finally, with regards to the central element generally indicated by 4 and seen with more detail in fig.'s 2 to 5, it is preferably but not necessarily consists of a tubular element 4a with a circular section that has holes 4b and 4c at its ends designed to receive the respective couplings of the first stiles 3c with their relative front legs 3a and back legs 3b. The ends of the tubular element 4a are closed by plugs 4d fastened by screws 4e According to the invention, the seat 5 is connected to the central element 4 through swivel means 10 designed to allow a planar rotary-transverse movement of said seat 5 combined with a rotary rocking movement of said backrest 6 around the longitudinal axis Y created by both of said first flexible couplings 7. The swivel means, as can be seen, count two and each of them, as can be seen in figures 9 to 16, include a first swivel element 11 that is solidly fixed to the seat 6 and a second swivel element 12 that is solidly fixed to the central element 4. They are connected together through flexible means consisting of a pliable body 13 attached to both through fixing means preferably being screws 13a. Said swivel elements 11 and 12 also have contact surfaces that touch, 11 a and 12a respectively, designed to work together during the reciprocal movement of the swivel elements to keep the movement of the seat 5 complainer with its original level. In particular the first swivel element 11 includes a cylindrical body 11 b that is fitted into its seating 5b of the seat 5 and has a first blind housing 11c that receives one end of the pliable body 13. On the outer rim 11 d of the cylindrical body 11 b defines the aforementioned contact surface 11 a. The second swivel element 12 is instead made of a tubular element 12b that has a sliding coupling on the outside of the tubular body 4a of central element 4 and has an curved outer rim 12c that defines the aforementioned contact surface 12a. In addition, a second blind housing 12e receives the other end of the pliable body. Between the swivel means 10 there is a spacer sleeve 14 on the outside of the central element 4 and set at its centre, which acts as a travel stop when the swivel means 10 are turning around the longitudinal axis X of the actual central body. The existence of elastic seals 14a between spacer and central element prevent foreign bodies from entering between the coupled surfaces. It works when the seated person pushes against the seat 5 or against the backrest 6 or against both, the force discharged onto the swivel means 10 generates an axial component along longitudinal axis X of the central element 4 that tends to shift the seat 5 in that direction and a tangential component that vice-versa tends to make it turn around the central element 4. A combination of the two movements thereby obtains a planar rotary- transverse movement that, as seen in figures 17 to 19, is developed keeping the seat 5 constantly parallel to plane π as it is found when in its idle position. At the same time as this planar rotary-transverse movement of the seat 5, a rocking movement of the backrest 6 is also obtained around the longitudinal axis Y created by the first flexible couplings 7, which varies its angle as shown in fig. 18. The seat 5 and the backrest 6, with reference to fig. 17, are therefore set in the positions indicated by the dotted line, with respect to the initial idle position that the same diagram shows by plain lines. In this way the seated person can easily change position of the backrest and the seat as desired, by shifting the latter forwards or backwards and at the same time even sideways, always keeping the seating plane quite parallel to its initial position. A variant in execution of the chair invention is illustrated in fig. 20, where it is generally indicated by 100. This differs from the variant in execution just described in that the frame, generally indicated by 200, includes a single, substantially upright supporting body 201 , which has its top 202 connected to the central element 4 of the chair and its bottom 203 provided with a floor standing components 204. Said floor standing components 204 are preferably provided with wheels 205 designed to make the chair mobile. With regards to its top 202, this can be telescopic from within its supporting body 201 thereby also making the chair adjustable in height. It is clear that the chair invention in both the executive variants that have been described and illustrated, may be constructed in any kind of form or size and may also have variations in execution concerning the flexible couplings and union means. Even though the invention has been described with reference to the figures illustrated in the attached diagrams, it may be subject to many changes and variations in execution, all falling under the inventive concept expressed by the attached claims.

Claims: CLAIMS 1 ) Chair (1 ; 100) with variable pitch including: - a frame (2; 200) set to rest on the floor; - at least one central element (4) that creates a substantially horizontal longitudinal axis (X), supported by said frame (2; 200); - a seat (5) supported by said central element (4); - one pair of first stiles (3c) parallel to each other and set at the ends of said central element (4); - a backrest (6) that has its top (6a) connected to each of said first stiles (3c) through flexible couplings (7) and its bottom (6b) connected to said seat (5) through at least one second flexible coupling (8), characterised in that said seat (5) is connected to said central element (4) through swivel means (10) designed to allow a planar rotary-transverse movement of said seat (5), combined with a rotary rocking movement of said backrest (6) around a longitudinal axis (Y) created by said first flexible couplings (7). 2) Chair (1 ) according to claim 1 ) characterised in that said frame (2) includes at least one pair of front legs (3a) connected to the ends of said central element (4) and at least one pair of back legs (3b) also being each connected to one of the ends of said central element (4). 3) Chair (100) according to claim 1 ) characterised in that said frame (200) consists of a single supporting body (201 ) having a substantially upright stature that has its top (202) connected to said central element (4) and its bottom (203) provided with floor standing components (204). 4) Chair (1 ) according to claim 2) characterised in that each front leg (3a) is set as a continuity of a corresponding first stile (3c) with which it creates a single, linear body. 5) Chair (1 ) according to claim 1 ) characterised in that the plane of said rotary-transverse movement made by said seat (5) is substantially parallel to the plane (π) on which said seat (5) rests when in its idle position. 6) Chair (1 ) according to claim 1 ) characterised in that said longitudinal axis (Y) created by said first flexible means (7) is substantially parallel to the longitudinal axis (X) created by said central element (4). 7) Chair (1 ) according to claim 1 ) characterised in that each of said swivel means (10) include a first swivel element (1 1 ) fixed to said seat (5) and a second swivel element (12) that slides over said central element (4) along the latter's longitudinal axis (X), said swivel elements (1 1 , 12) being connected together through flexible means (13). 8) Chair (1 ) according to claim 7) characterised in that each of said swivel elements (1 1 , 12) have contact surfaces (11 a, 12a) that touch together. 9) Chair (1 ) according to claim 7) characterised in that said first swivel element (1 1 ) consists of a cylindrical body (1 1 b) that is received in a seating (5b) made in said seat (5) and has a first contact surface (11a) on its outer rim (1 1 d) and a first blind housing (1 1 c) designed to receive said flexible means (13). 10) Chair (1 ) according to claim 7) characterised in that said second swivel element (12) is made of a tubular element (12b) with its outside having a second contact surface (12a) made on the curved outer rim (12c) and on its outside it has a second blind housing (12e) designed to receive said flexible means (13). 1 1 ) Chair (1 ) according to claim 7) characterised in that said flexible means (13) consist of at least one pliable body inserted between said swivel elements (1 1 , 12) and fixed to both through fixing means. 12) Chair (1 ) according to claim 1 1 ) characterised in that said flexible means (13) are made in elastomer. 13) Chair (1 ) according to claim 2) characterised in that said central element (4) consists of a tubular body (4a) with a circular section that has holes (4b, 4c) at its ends designed to receive said first stiles (3c) and said legs (3a, 3b). 14) Chair (1 ) according to claim 1 ) characterised in that each first flexible coupling (7) includes a clamp (9) coupled to its relative first stile (3c) and a pliable body (9c) inserted between said clamp (9) and said backrest (6), said clamp (9) and said pliable body (9c) having a hole (9d) designed to receive first union means (9e, 9f) to tighten the clamp and lock said backrest (6) to its relative first stile (3c). 15) Chair (1 ) according to claim 14) characterised in that said clamp (9) consists of two halfrings (9a) that together create a seating (9b) that receives said first stile (3e). 16) Chair (1 ) according to claim 1 ) characterised in that said second flexible coupling (8) includes a substantially cylindrical element (8a), which can be flexed out of shape, inserted between the bottom (6a) of said backrest (6) and the back (5a) of said seat (5) to which it is fixed through second union means (8c, 8d).

Inventors: CIONCADA ENRICO, CIONCADA, ENRICO
Applicants: CIONCADA ENRICO, CIONCADA, ENRICO
Application year: 1999
Main classification: A47C1
IPC codes: A47C1, A47C3