Mechanical device, particularly for the movement and selective locking of a chair

Abstract: The mechanical device, particularly for the movement and selective locking of a chair, comprises a pair of arms (3a,3b) to be fastened to the chair and consists of a swivel boxlike element (5) associated with a pivoting pin (4) integral with said pair of arms (3a,3b), which contains a molding box (20) integral with said pin (4). The molding box (20) interacts both with means of resilient opposition (24,25) to said boxlike element and with a separate means for the selective locking of the position of the chair with regard to the boxlike element (20) and for the control for a gas piston. This mechanical device makes it possible to achieve an optimal adjustment of the chair by directly acting on the selective locking means which interacts with the molding box (20).

Description: The present invention relates to a mechanical device particularly for the movement and the selective locking of a chair. Currently there are well-known mechanical devices, which are used to adjust the tilt of a chair. One well-known type consists of a chair whose seat is fixed with regard to the column projecting from a swivel base, with the possibility of tilting the back in relation to the seat. This type, however, presents an annoying drawback whenever the user shifts his position on the seat as a result of the natural stretching of the user's body. As a partial solution to this drawback, it is common to make a seat and back connected to each other so that a tilt of the back is accompanied by a shift or tilt of the seat: therefore, below the seat there is usually a first lever used to control a gas piston that lifts the seat to a greater or lesser degree and another lever used to operate a mechanism installed for tilting to a greater or lesser degree. This well-known type presents some drawbacks: the use of two levers forces the user to seek specifically the one he wants with the result that many times the wrong control is used requiring the user to go back to the former condition. Furthermore, a certain amount of dexterity is required from the user who must seek out the two levers without being able to see them. Lastly, the mechanisms that interact with the two levers are of necessity complex and therefore their construction is expensive. Known from EP-A-0,392,984 is a mechanical device, particularly for the movement and the selective locking of a chair as defined in the preamble of claim 1. However, this known device has two levers for the control of the chair, which requires a certain dexterity on the part of a user. Also known from FR-A-2,075,176 is a single-lever device for the movement and the selective locking of a chair, however, this known device is structurally complex and expensive to manufacture. The main aim of the present invention is therefore to eliminate the above-mentioned drawbacks in well-known types by devising a mechanical device that, once it has been attached to a chair will make it possible to attain an optimal adjustment in the positioning of said chair by performing operations that are quick and easy for the user. Within the scope of the above-mentioned aim, another important object is to provide a mechanical device that will make it possible for the user to obtain these adjustments selectively and, therefore, according to specific requirements. Yet another important object is to provide a device which is structurally simple and easy to manufacture. A further object of the invention is to provide a mechanical device which will prove reliable and safe to use, with rather limited costs that will increase its application even on chairs whose overall value is not high. The above-mentioned aim and objects, as well as others which will become apparent hereinafter, are achieved by a mechanical device, particularly for the movement and selective locking of a chair, as defined in the independent claim 1. Various embodiment of the device according to claim 1 are defined in the dependent claims 2 to 8. Further characteristics and advantages of the invention will become apparent from the detailed description of a particular but not exclusive embodiment, illustrated only by way of non-limitative example in the accompanying drawings wherein: Figure 1 shows the device in an exploded view; Figure 2 shows the device in a three-quarter partially cross-sectional view; Figure 3 shows the device in the non-tilting condition for the chair if the shaft 18 is inserted in the third hole 16c made on the tab 16b; Figure 4 shows the device in the condition of possible tilting for the chair if the shaft 18 is withdrawn from the third hole 16c. With reference to the above figures, the mechanical device, identified by reference sign 1, proves particularly usable for the movement and selective blocking of a chair 2 attachable at the upper part to a pair of arms 3a and 3b integrally connected transversely and at one end to a pivoting pin 4. A first boxlike element 5 is attached in a swivel fashion to said pivoting pin 4 proximate to the ends integral with the pair of arms 3a and 3b. From this boxlike element which, when viewed from above, has a triangular shape, there project laterally a pair of first appendages 6a and 6b equipped with preformed first holes 7a and 7b for the fastening by means of the first and second screws, indicated by the reference numerals 8a and 8b respectively, and two pairs of sleeves 9a, 9b and 10a, 10b. Alternatively, the connection between both pairs of sleeves may be made by gluing them or by means of a recess or other equivalent solution. These last items are preferably made of self-lubricating plastic material, such as nylon, and can be closed up between each other by means of the first and second screws in order to allow the swivel connection to the pivoting pin 4 of the boxlike element 5. Advantageously, a U-channel 11, can be temporarily associated at the back with the two pairs of sleeves in order to conceal them. The boxlike element has in connection with its vertex a conical bushing 13, fitted for receiving the end of a column 14, provided with a control 15 for the gas supply. The boxlike element 5 has laterally a second hole 16a and, in connection with a preformed tab 16b, projecting internally, a third hole 16c, these second and third holes having the same axis transversal to the boxlike element 5 in relation to them, which can be positioned, and with the end 17 of an accessible shaft 18 passing through to the other end to the user. In the interspace between the second holes there projects, from the end 17 of the shaft 18, a second appendix 19 able to interact, by turning the shaft, with the control 15 for the gas supply. Furthermore, there is a box-shaped lever or molding box 20, with an essentially trapezoidal shape, whose larger end 21 is linked to the pivoting pin 4, that can be associated with said boxlike element 5. This molding box 20 has a longitudinal extension lower than that of the boxlike element 5, which extension is provided laterally with a third appendage 22 which extends beyond the smaller end 23. This third appendage 22 is located in the interspace between the planes in which the tab 16b and the adjacent lateral surface of the boxlike element lie. Below the molding box 20 there are means of resilient opposition comprising a small pin 24, around which there is a spring 25 to which it is associated and a knob 26 at one end, which passes through the molding box 20 and the boxlike element 5 at the fourth and fifth holes made therein and indicated by the reference numerals 27 and 28. The shaft 18 is a means which is able to permit the selective locking of the position of the chair with regard to the boxlike element and which is for operating the gas control. The use of the mechanical device 1 is as follows: once the user has seated himself on the chair, he may easily modify its disposition, predetermining both its height above the floor and its tilt, doing so by merely acting on the single shaft 18, which projects laterally from the mechanical device 1. Advantageously, the action of the user on said shaft 18 may be divided into two phases, depending on whether he wants to act on the locking or the activation of the tilt or on the gas-piston control. Starting with the condition shown in figure 2, wherein the shaft 18 engages both the second hole 16a and the third hole 16c and the third appendage 22 of the molding box 20 presses against the far end of the shaft 18 from below, the chair is permitted to tilt against the spring 25. Grasping the shaft 18 and pulling outward, the user can withdraw said shaft and free its far end from the third hole 16c; by so doing, the condition of free tilting is obtained for the chair. If the user reinserts the end of the shaft 18 in the third hole 16c, two different situations can be obtained: if the third appendage 22 is lodged between the upper surface of the molding box 20 and the end of the shaft 18, as illustrated in figure 3, the user may remain seated in a working position since it is not possible for the chair to revolve around the pin. If, instead, the end of the shaft 18 is lodged between the upper surface of the molding box 20 and the third appendage 22, as illustrated in figure 4, the user may remain seated in a relaxed position since the chair is slightly inclined backwards. If, instead, the user wants to operate the gas-piston control 15, he should grasp the end fin 29 of the shaft 18 pulling it upward: by so doing, the second appendage 19 squeezes the aforesaid control 15 activating the gas supply and thereby varying the height position of the chair. These operations may, furthermore, be done "blindly", in view of the extreme operating simplicity and the accessibility of the shaft which, since there is only one, is easy for the user to locate. It is thus observed how the invention achieves the above-mentioned aim and objects, there being provided a mechanical device that makes it possible to achieve an optimal positioning of the chair by means of directly acting on the only locking means, consisting of the shaft 18 which interacts with the molding box 20. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims: Mechanical device (1), particularly for the movement and the selective locking of a chair, comprising a pair of arms (3a,3b) to be fastened to said chair, a boxlike element (5), attached in a swiveling fashion to a pivoting pin (4) integral with said pair of arms (3a,3b), and a lever (20), integral with said pin (4) and interacting through resilient means (24,25) with said boxlike element (5), characterized in that the device comprises a shaft (18) for the selective locking of the position of said chair with regard to said boxlike element (5) and for the control of a gas piston, a pair of first appendages (6a, 6b) projecting laterally from said boxlike element (5), and sleeves (9a, 9b, 10a, 10b) connected to said appendages (6a, 6b) for swivelling connection of said boxlike element (5) to said pin (4). Device according to claim 1, characterized in that said boxlike element (5), comprising with regard to its vertex a conical bushing (13) fashioned to receive the end of a column (14) provided with a control (15) for the gas supply, has laterally a second hole (16a) and, in relation to a predisposed tab (16b) projecting internally, a third hole (16c), said second and third holes (16a,16c) having the same axis transversal to said boxlike element (5); with regard to said holes (16a,16c), there is the end (17) of said shaft (18) which can be positioned and passes therethrough, which shaft (18) is accessible at the other end by the user. Device according to claim 2, characterized in that in an interspace between said second and third holes (16a,16c), there projects from said end (17) of said shaft (18) a second appendage (19) designed to interact, when said shaft (18) is turned, with said control (15) for the gas supply. Device according to claim 3, characterized in that said lever (20) has an essentially trapezoidal shape defining a smaller end (23) and a larger end (21), said larger end (21) being linked to said pivoting pin (4), said lever (20) extending longitudinally below said boxlike element (5) and presenting laterally a third appendage (22) which extends beyond said smaller end (23). Device according to claims 2 and 4, characterized in that said third appendage (22) is positioned in an interspace defined between the planes in which lie said tab (16b) and the adjacent lateral surface of said boxlike element (5). Device according to claim 1, characterized in that said resilient means (24, 25) are located below said lever (20) and comprise a small pin (24), a spring (25) extending around said pin (24), and a knob (26) located at one end of said pin (24), said pin (24) passing through said lever (20) and said boxlike element (5) in fourth (27) and fifth (28) holes provided therein. Device according to one or more of the preceding claims, characterized in that the end (17) of said shaft (18) inside said boxlike element (5) is insertable in said third hole (16c) for positioning said third appendage (22) above or below the shaft (18), said shaft (18) permitting tilting of said chair upon withdrawal of said end (17) from said third hole (16c). Device according to one or more of the preceding claims, characterized in that it comprises a U-channel (11) temporarily rearwardly connectable to said two pairs of sleeves (9a,9b,10a,10b) to conceal them.

Inventors: MIOTTO BENIAMINO, MIOTTO LORIS, MIOTTO, BENIAMINO, MIOTTO, LORIS
Applicants: MIOTTO INT COMP, MIOTTO INTERNATIONAL COMPANY
Application year: 1992
Main classification: A47C3
IPC codes: A47C3