Abstract:
An armrest of a chair which can be adjusted and which can be moved in a transverse horizontal direction with respect to the longitudinal direction of the armrest. Regardless of the position thus obtained, the armrest is capable of turning on an essentially vertical axis between two extreme positions, so to adapt to the specific needs of the user and to the activities to be performed in an optimal way.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to armrests for chairs, armchairs or similar of the type comprising a supporting column and an armrest body connected to the upper extremity of the supporting column. 
     Particularly in the case of office chairs, a known type presents a mobile armrest in a transverse horizontal direction with respect to the longitudinal direction of the armrest, so to adapt the position of the armrest to the specific requirements of the users and also to the different activities, which the user can carry out. For example, working at the keyboard of a typewriter or computer requires a respectively relative close position of the two armrests of the chair for the purpose of suitably supporting the wrists of the user during work. Conversely, a relaxing position, with the back resting on the backrest of the chair, preferably requires a respectively more distanced positioned of the two armrests. The solutions proposed to date do not always satisfy said needs adequately and, moreover, do not account for the additional need for the user to have a suitable support of the forearms in all the possible positions they can assume. 
     SUMMARY OF THE INVENTION 
     The purpose of this invention is to attain an armrest, which is capable, on one hand, to efficiently solves all said problems, and which, on the other hand, presents a relative simple, cost-effective structure. 
     In order to attain this purpose, this invention relates to an armrest of the type illustrated at the beginning of this description, characterised in that: 
     the armrest body pivots on a first axis, which is essentially vertical on an intermediate supporting element and can assume various angular positions around said first axis, 
     the intermediate supporting element is connected to the armrest supporting column so to move in a direction, which is essentially transverse and horizontal with respect to the longitudinal direction of the armrest, so that the latter can also be positioned in various operative positions with respect to the supporting column, transversely with respect to the longitudinal direction of the armrest. 
     Thanks to these characteristics, the user sitting in a chair provided with two armrests according to this invention can easily space out or bring nearly the two armrests, according to the users preferences or requirements. At the same time, for each transversal position, the armrest can be oriented on said first essentially vertical axis, in such a way to provide a suitable support to the respective forearm, regardless of the position of the latter on the horizontal plane. 
     According to an additional characteristic of the armrest according to the invention, positioning devices for defining at least two extreme angular positions of the armrest body, turned in opposite directions around said first vertical axis, in addition to an unturned neutral position, are arranged between the armrest body and the intermediate supporting element. 
     Furthermore, in the preferred form of embodiment of this invention, said intermediate supporting element is connected to the supporting column by means of an articulated vertical axis parallelogram linkage system, which can pivot between two opposite extreme positions. Preferably, the articulated parallelogram linkage system comprises a pair of arms, articulated both on two vertical axes on the supporting column and on two vertical axes of said intermediate supporting element. 
     In this description and in the claims that follow, the term “vertical” is used with reference to a normal horizontal condition of the armrest. However, the armrest according to this invention can also be used in a chair described in a co-pending patent application by the Applicant, in which the backrest can recline backwards along with the supporting column of each armrest. In the reclined condition, said first axis, on which the armrest body can pivot, is no longer vertical, but remains in any case perpendicular to the general plane of the armrest body. 
     Always in the case of this preferred form of embodiment, the reference devices of the first angular operative angular position on said first axis comprise an engaging element connected to the intermediate supporting element, which is made to co-operate with an elastic element connected to the armrest body and with several reception housings of the engaging element for defining various operative angular positions of the armrest around said first axis. 
     According to an additional preferred characteristic of this invention, said supporting column can be adjusted in length, to allow adjusting the height of the armrest body. For this purpose, the supporting column comprises an internal tube destined to be connected to an element belonging to the structure of the chair, and an external tube fitted so to slide around the internal tube and can be blocked in any position between a plurality of various operative positions, by means of fastening devices which can be released manually. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention will be better explained by the following detailed descriptions with reference to the accompanying figure as non-limiting example, whereas: 
     FIG. 1 is a lateral cross-section view of a preferred form of embodiment of the armrest according to this invention, 
     FIG. 1A is a blown-up view of a detail in FIG. 1, 
     FIG. 2 is a view similar to that of FIG. 1 illustrating the armrest in a position adjusted to a greater height, 
     FIG. 3 is a cross-section view according to the line III—III in FIG. 1, 
     FIGS. 4,  5  are cross-section, scaled-down views, similar to FIG. 3, showing the armrest body in two different operative positions turned on the horizontal plane, 
     FIG. 6 is a cross-section view according to the line VI—VI in FIG. 1, 
     FIGS. 7,  8  are cross-section, scaled-down views, similar to FIG. 6, showing the armrest body in two different operative positions moved in a perpendicular horizontal direction with respect to the longitudinal direction of the armrest, 
     FIG. 9 is a plan view of a chair using two armrests according to this invention, and 
     FIGS. 10,  11  and  12  illustrate a blown-up view of three details of the armrest according to this invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to FIGS. 1,  2 , numeral  1  generally indicates an armrest for an office chair, comprising an armrest body  2  fitted on the upper extremity of a vertical supporting column  3 . The column  3  comprises an internal metal tube  4 , which lower end is destined to be connected in any way to the structure of a chair presenting, in the example shown, a relatively flat cross-section, with two opposite flat faces  4   a,  according to a profile which is essentially similar to that indicated with numeral  5  and illustrated with the dotted line in FIG.  3 . The profile  5  refers, in fact, to the cross-section of an external tube  5 , which is fitted so to slide outside the tube  4 . In this way, the supporting column  3  can assume different operative conditions, including a minimum length position, illustrated in FIG. 1, and a maximum length position, illustrated in FIG.  2 . The relative sliding movement of the two tubes  4 ,  5  is guided by means of a plastic material bushing  6 , which is externally ensured to the upper extremity of the internal tube  4 , and over which the internal surface of the external tube  5  slides. The supporting column  3  is located in the selected condition by engaging a transverse pin  7  connected to the two opposite sides  4   a  for the internal tube  4  in a housing  8 , selected from an aligned set of housings made in an arm, for example made of plastic material (also see FIG.  10 ), which is articulated inside the internal tube  5  by means of a transverse pin  10 , fitted between the two opposite flat sides of the external tube  5 . The arm  9  incorporates, in a single part, the operating lever  11  for controlling the clockwise rotation of the arm  9  (with reference to FIGS. 1,  3 ) to the position illustrated with the dotted line in FIG. 2, in such a way to release the pin  7  from the respective housing  8 , in which it is engaged so to adjust the height of the armrest. The arm  9  also incorporates, in a single part, an elastic reed  12 , which is extended as arm  9  inside the internal tube  4  and is pressed elastically against the internal surface of the tube  4 . When the user operates the lever  11  moving it upwards, so to turn the arm  9  towards the released position shown with a dotted line in FIG. 2, it must overcome the elastic resistance of the reed  12 , which must return the arm  9  to the engaged position as soon as the user ceases to exert an action on the lever  11 . Consequently, to adjust the height of the armrest, the user must pull the lever  11  upwards, against the action of the reed  12 , so to release the pin  7  from the housing in which it is engaged, after which the height of the armrest can be adjusted holding the lever operated, so to permit the free movement of the arm  9  with respect to the pin  7 . Finally, the lever  11  is released when the required height is reached. In this way, the pin  7  will be received in the closest housing  8 , possibly with a slight vertical movement to settle the armrest, under the effect of the recalling action of the reed  12 . A front view of the arm  9  is shown in FIG. 10 of the accompanying drawings. 
     A metal plate  13 , which is visible in the plan view in FIG. 11 of the accompanying drawings, is welded to the upper extremity of the external sliding tube  5 . The plate  13  comprises a central slot  14  to prevent interference with the lever  11  for releasing the height adjustment of the armrest, and two holes  15  in which two vertical axis pins  16  are welded. A plastic material plate  17  is positioned over the metal plate  13 , illustrated in the plan view in FIG. 12, presenting two holes  18  for engaging over the two pins  16 , and two sets of three spherical cavities  19 , each concentric with respect to the respective hole  18 . Furthermore, a hemispherical boot  20  made of plastic material, with a lower aperture encompassing the external tube  5  and an upper mouth  20   a , is fastened to the upper part of the external tube  5 . The boot  20  presents a front slot  20   b  to prevent interference with the armrest height adjustment release lever  11 . 
     Also with reference to FIGS. 6-8, two respectively parallel articulated arms are fitted so to pivot on the two vertical pins  16 , visible in the plan view in FIGS. 6,  7 ,  8 , one of which is visible in the cross-section view in FIG.  1 . Each arm  21  consists of a body made of plastic material fitted so to pivot on two pins  16  projecting vertically from the metal plate  13 . The reference numerals  22  indicate the axes of the two pins  16 . The opposite extremities of the two articulated arms  21  are, in turn, articulated by means of respective pins  23  onto an intermediate supporting element  24 , comprising a metal plate  25 , which shape is essentially triangular, with one side connected to two articulated arms  21  and a front extremity, which is welded to a vertical pin. The set of two articulated arms  21  consequently forms an articulated parallelogram linkage system, which connects the intermediate supporting element  24  to the plate  13  welded to the upper extremity of the supporting column  3 , so that the intermediate supporting element  24  can be moved in the perpendicular horizontal direction with respect to the longitudinal direction of the armrest between two extreme positions, illustrated in FIG.  7  and FIG. 8, respectively. With reference to FIG. 1A, each of the arms  21  presents a vertical cavity  27  opening downwards in which a tip  28  slides. The tip is pushed by a coil spring arranged in the cavity  27  and co-operates with the respective set of three cavities  19  in the plate  17 , for providing a precise reference for the intermediate position, illustrated in FIG. 6, and the extremity positions, illustrated in FIGS. 7,  8 , of the transverse regulation movement of the intermediate supporting element  24 . The articulated parallelogram linkage system consists of two arms  21  and is arranged inside a plastic material box, indicated in general with reference numeral  29 , which consists of a lower casing and an upper casing, joined together, and which is fitted so to turn on the upper mouth of the hemispherical boot  20  and around the two plates  13 ,  17  in such a way to accompany the articulated parallelogram linkage system in its movement, as can clearly be seen in FIGS. 7,  8 . 
     A bushing  30  made of plastic material is fitted so to turn on the vertical pin  26  (which axis is indicated with reference numeral  38 ) which projects from the upper part of the metal plate  30 . The lower part of the bushing presents three axial prongs received in respective cavities by plate  25  so that the bushing  30  is locked in rotation with respect to the plate  25  and the pin  26 . The bushing  30  is an integral part of the a plastic casing, including a plate  31 , which shape is essentially circular (also see FIGS.  3 - 5 ), including a pointed appendix  31   a , which is an engaging element  32 , for co-operating with a plastic material clip  33  (see FIGS.  3 - 5 ), jammed in a housing  34  in the plastic material casing forming the body  2  of the armrest. The body  2  consists of two plastic material casings, which are coupled by means of screws  35 . The upper plate presents a tubular internal appendix  36 , which is fitted so to turn on an extremity of the bushing  30  projecting from the upper part of the plate  31 . Furthermore, the part of the casing forming the armrest body  2  presents a circular circumference side  37  (see FIGS.  1  and  3 - 5 ), extending approximately by approximately 270 degrees, which surrounds the circular edge of the plate  31 , and which thus acts as a fulcrum for the oscillation of the armrest body  2  on the axis  38  of the pin  26 . This axis is positioned essentially perpendicularly to the centre of the armrest, at distances which are essentially equal to that of the two extremities of the armrest (also if, naturally, a different positioning of the axis  38  with respect to the armrest is possible). In correspondence of the appendix  31   a  of the plate  31 , the extremities of the side  37  extend with two parallel sides  39 , which are sufficiently distanced to prevent interference with the appendix  31   a  in the two extreme turned positions of the armrest  2  to the left and to the right (FIGS. 4,  5 ). 
     The clip  33  consists of a plastic material rod wrapped to form a closed ring, defining a central housing  40 , which receives the engaging element  32  in the neutral position not turned in the armrest body  2  visible in FIG. 3, and two lateral sides  41 , which co-operate with the two sides  39  for receiving the engaging element  32  in the two extreme turned positions to the right and to the left of the armrest body  2 , respectively (see FIGS. 4,  5 ). 
     In this description, it appears obvious that the armrest body  2  can be adjusted in the vertical direction, by sliding of the external tube  5  in the internal tube  4  and locked by means of the locking device  7 ,  9 , described above, and in the horizontal direction, transversely with respect to longitudinal direction of the armrest, thanks to the orientation of the articulated parallelogram linkage system consisting of the arms  21  (see FIGS. 7,  8 ). Furthermore, for each position of the armrest in height, and for any position of the intermediate supporting element  24  (consisting of the plate  25 , the pin pivoting on the axis  38 ), between the two extreme positions which are illustrated in FIGS. 4,  5 . 
     FIG. 9 shows a plan view of the a chair according to this invention, incorporating a pair of armrests of the type described above. The dotted lines illustrate all the positions which the armrests can assume. As can be seen, each armrest can be moved transversally between two extreme positions. Furthermore, in each of said extreme positions, and in the intermediate neutral position, each armrest can be oriented by means of oscillations on the axis  38  so to assume an orientation, which is straight or turned either leftwards or rightwards. 
     Thanks to these characteristics, the user can adapt the armrests optimally according to the needs deriving from the user&#39;s build and the specific activity to be carried out (for example, a relaxing position or a position for working on a keyboard). 
     Naturally, numerous changes can be implemented to the construction and forms of embodiment of the invention herein envisaged, all comprised within the context of the concept characterising this invention, as defined by the following claims.