Patent Publication Number: US-11026514-B2

Title: Adjustment device for a chair with rocking mechanism

Description:
The present invention relates to an adjustment device for a chair that has a rocking mechanism. 
     Nowadays it is known to provide chairs that are fitted with a mechanism the function of which is to enable for example the height adjustment of a seat and the adjustment of the rocking, or the locking in place, of a backrest. 
     An example of the mentioned prior art is disclosed in U.S. Pat. No. 6,120,096, where the activation of the mechanisms which interact with the seat and with the backrest are activated by way of using a first lever, the rotation of which leads to the packing or otherwise of special slats, and also a second lever, the lifting of which leads to its terminal end interacting with a gas-filled piston present on a central gas-operated post. 
     Such rocking mechanisms are structurally complex and require a certain force of the user in order to activate the packing of the slats, which may also be subject to possible seizing. 
     EP 2554075B1 is also known, which relates to a chair with a rocking mechanism,
         wherein the rocking mechanism has a fixed base support with a conical receptacle, said fixed base support being placeable by means of the conical receptacle on a chair pillar of the chair,   wherein the base support is connected pivotably to a mechanism upper part, which forms a housing at least partially enclosing the base support,   wherein the pivot axis of the mechanism upper part, which pivot axis runs transversely with respect to the chair longitudinal direction, is arranged next to the conical receptacle, as seen in the chair longitudinal direction,   wherein at least one spring element, interacting on the one hand with the mechanism upper part, and on the other hand with the base support is provided in order to return the mechanism upper part, from a pivoted position into a starting position, and   wherein the rocking mechanism is fastened by means of the mechanism upper part to a seat, a seat support or a frame of the chair, or the rocking mechanism is integrated into the seat, the seat support or the frame of the chair, in such a manner that the mechanism upper part is formed by part of the seat, of the seat support or of the chair frame,       

     characterized in that a valve pin for triggering a pneumatic spring placed in the interior of the chair pillar is located in the region of the conical receptacle, and, in order to trigger the pneumatic spring, a pivot lever interacting with at least part of the rocking mechanism is provided for actuating the valve pin, 
     and in that the pivot lever is placed in such a manner that the axis of rotation of the pivot lever coincides with the pivot axis of the mechanism upper part. 
     This solution also has drawbacks: the fact that the rotation axis of the rocking lever is identical to the orientable axis of the upper part of the mechanism entails a compaction of the positioning of the components which compromises the achievement of an optimal rocking and of the optimal activation of the gas-filled post, given that the rocking lever, in order to actuate the pin of the valve of the pneumatic or gas-filled shock absorber, must interact with at least a part of the rocking mechanism. 
     In such solution, furthermore, there is a device for preventing the tilting function, to which movements can be imparted on both a vertical plane and on an oblique plane, making it rather unreliable owing to possible sticking or malfunction. 
     The aim of the present invention is to solve the above mentioned technical problems, eliminating the drawbacks in the cited known art, by providing a device that makes it possible to achieve at the same time, rapidly, simply and optimally, both the activation and prevention of rocking for a chair, and also the activation of the raising of said chair. 
     Within this aim, an object of the invention is to provide a device that, in addition to the foregoing characteristics, is also structurally simple and free from sticking. 
     Another object is to provide a device that is low cost and which can be made with the usual conventional systems. 
     This aim and these and other objects which will become better apparent hereinafter are achieved by an adjustment device for a chair which comprises a rocking mechanism composed of a first plate, which is fixed to a central gas-operated post for the height adjustment of a seat and to which a second plate is articulated, about a first axis that is transverse thereto and so that it can rock, said second plate being fixed to a seat or being integral with a seat and interacting with means which are adapted to contrast the rocking of a backrest, 
     characterized in that a first cable is slideably associated with said first plate and is adapted to activate a lever which is articulated internally to said first plate at a second, different axis and is adapted to activate the height adjustment of said seat, a second cable being furthermore slideably associated with said first plate and being adapted to activate a mechanism which allows or prevents the rocking of said second plate. 
    
    
     
       Further characteristics and advantages of the invention will become better apparent from the detailed description of a particular but not exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein: 
         FIG. 1  is a perspective view from below of the device applied to a central gas-operated post; 
         FIG. 2  shows the device, without the plate associated with a backrest; 
         FIG. 3  is a different view of the device of the previous figure; 
         FIG. 4  is a view from above of the device of the previous figure in the free-rocking condition; 
         FIG. 5  is a cross-sectional view of the device taken along the line V-V of  FIG. 4 ; 
         FIG. 6  shows the device of the previous figure in the condition of activation of the central gas-operated post; 
         FIG. 7  is a cross-sectional view of the device taken along the line VII-VII of  FIG. 4 ; 
         FIG. 8  is a cross-sectional view of the device taken along the line VIII-VIII of  FIG. 4 ; 
         FIG. 9  shows the device of the previous figure in the free-rocking condition; 
         FIG. 10  shows the device of  FIG. 4  in the rocking-prevented condition; 
         FIG. 11  shows the device of  FIG. 8  in the rocking-prevented condition; 
         FIG. 12  shows the first plate with some components inserted; 
         FIG. 13  is a perspective view of the mechanism that allows or prevents the rocking of the second plate. 
     
    
    
     In the exemplary embodiments that follow, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments. 
     Moreover, it is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer. 
     With reference to the figures, the reference numeral  1  generally designates an adjustment device for a chair (not shown) which comprises a rocking mechanism composed of a first plate  2 , which has a substantially C-shaped box-like shape so as to define a flat first base  3  and two first side wings  4   a ,  4   b ; at the first base  3  there is a protruding bushing  5  at which the end of a stem  6  of a central gas-operated post  7 , mounted on a footing and used for the height adjustment of a seat (not shown), is associated. 
     A second plate  10 , which is fixed to a seat (not shown) or can be constituted also by a component integral with the seat, is articulated to the first plate  2  so that it can rock, by virtue of first pivots  8   a ,  8   b  which lie on a first axis  9  which is transverse and eccentric with respect to the first plate  2 . 
     The first plate  2  interacts with means adapted to contrast the rocking of the backrest, such means being constituted by a pair of first springs  11   a ,  11   b  which protrude from the first base  3  and are interposed between the latter and the second plate  10 . 
     At one side of the first plate  2 , directed toward the front part of the seat, a first cable  12  is slideably associated and is adapted to activate a lever  13 , which is articulated internally to the first plate  2  at a second axis  14 , different from the first axis  9 , and arranged at an angle to the longitudinal axis of the first plate  2 . 
     The lever  13  is L-shaped so as to define a first wing  15 , which is directed toward the first base  3 , and a second wing  16 , which is adjacent to and lies above the central gas-operated post  7 , and such lever is pivoted, in the connecting region between the first wing and the second wing  15 ,  16 , to a second pivot  17  arranged at the second axis  14 . 
     One end of the first cable  12  is connected to the free end of the first wing  15  so that a traction imposed on the first cable  12  is followed by a rotation of the lever  13  so as to make the terminal end of the second wing  16  interact with the central gas-operated post  7 , so as to activate the height adjustment of the seat. 
     Advantageously a tab  18  protrudes radially to the second wing  16  and interacts with a second spring  19  which is interposed between the tab  18  and the underlying first base  3  of the first plate  2 . 
     Such second spring  19  allows the return to a neutral position of the lever  13  once the first cable  12  has been released so as to not activate the central gas-operated post  7 . 
     A second cable  20  is further slideably associated with a side of the front part of the first plate  2  which lies opposite the side for inserting the first cable  12 , the second cable being adapted to activate a mechanism  21  which allows or prevents the rocking of the second plate  10 . 
     Such second cable  20  is guided inside the first plate  2  so that its terminal end  22  arranges itself proximate to the bottom of a first cavity  23  which is provided inside and longitudinally to the first plate  2 , on a side thereof which lies opposite the entry side of the first cable  12 . 
     Such mechanism  21  is constituted by a slider that has a substantially S-shaped plan configuration so as to define a first arm  24  which is shaped like a parallelepiped and is accommodated inside the first cavity  23  with the possibility to slide axially with respect to the first cavity  23  in contrast with a third spring  25  which is interposed between the vertical rear wall  26  of the first arm and a facing wall  27  of a block  28  which is associated internally with the first plate  2  in front of the first cavity  23 . 
     A bridge  29  is connected to the upper end of the first arm  24  and is arranged along an axis that is inclined with respect to the longitudinal axis of the first plate  2 ; a second arm  30  is connected in a lower region to the terminal end of the bridge  29 , which lies substantially at the longitudinal central axis of the first plate  2 , the second arm being parallelepiped-shaped, having a substantially T-shaped plan configuration, and being accommodated inside a second cavity  31  which is provided in the rear region of the first plate  2  where the first springs  11   a ,  11   b  also are arranged. 
     The second arm  30 , which slides freely and axially with respect to the second cavity  31  along an axis that is longitudinal to the first plate  2 , has a first shank  32 , with a rectangular plan shape, which is arranged in the interspace between the first springs  11   a ,  11   b , and the upper surface  33  of which is arranged on a plane that lies lower than the plane of arrangement of the bridge  29 . 
     The axial movement of the second arm  30  is guided, since that arm lies between a pair of shoulders  34   a  and  34   b , which are mutually parallel and protrude at right angles to the second cavity  31 ; the longitudinal extension of each one of the pair of shoulders  34   a  and  34   b  is substantially equal to the length of the shank  32 . 
     A first head  35  is connected to the first shank  32  and has a rectangular plan shape with dimensions such that its third wings  36   a ,  36   b  protrude laterally beyond the space occupation of the pair of shoulders  34   a  and  34   b : this determines the point of maximum retraction of the first head  35 , and therefore of the mechanism  21 , within the second cavity  31 . 
     In this condition an empty space  37  is defined, between the terminal end of the first head  35  and the bottom wall  38  of the second cavity  31 , which constitutes a temporary seat for a tooth  39  which protrudes internally and downward with respect to the second plate  10 . 
     This condition corresponds to the possibility for the second plate  10  to rock with respect to the first plate  2 , as shown in  FIGS. 8 and 9 . 
     The first shank  32  and the first head  35  advantageously interact with adapted guides, such as a T-shaped bar  40 , the second head  41  of which is arranged transversely so as to connect the upper terminal ends of the pair of shoulders  34   a  and  34   b  which are directed away with respect to the bridge  29 . 
     The second head  41  lies above the underlying upper surface  33  of the first shank  32 . 
     The bar  40  has a second shank  42  which arranges itself along the longitudinal axis of the first plate  2  in the direction of the bottom wall  38  and surmounts, in the free-rocking condition for the second plate  10 , the entire thickness of the first head  35 . 
     An additional guide for the sliding of the first shank  32  and the first head  35  is provided by the presence of a longitudinal ridge  43  which protrudes from the bottom of the second cavity  31  and is accommodated inside a complementarily-shaped seat  44  which is provided below the first shank  32  and optionally also below the first head  35 . 
     The third spring  25  pushes the mechanism  21 , bringing the second head  35  adjacent to the bottom wall  38  of the second cavity  31 , thus preventing the rocking of the second plate  10 . 
     The activation of the second cable  20  causes the retraction of the mechanism  21  until the second head  35  is brought into abutment against the end of the pair of shoulders  34   a  and  34   b , thus freeing up the empty space  37  in order to temporarily accommodate the tooth  39  thereat. 
     Thus it has been found that the invention fully achieves the intended aim and objects, an adjustment device for a chair that has a rocking mechanism having been obtained that makes it possible to achieve at the same time, rapidly, simply and optimally, both the activation and prevention of rocking for a chair, and also the activation of the raising of that chair. 
     Furthermore the device is structurally simple and free from sticking. 
     Naturally the materials used as well as the dimensions of the individual components of the device according to the invention may be more relevant according to specific requirements. 
     The characteristics indicated above as advantageous, convenient or the like, may also be missing or be substituted by equivalent characteristics. 
     The disclosures in Italian Patent Application No. 102017000057341 from which this application claims priority are incorporated herein by reference.