Patent Publication Number: US-6663182-B1

Title: Adjustable armrest for chairs

Description:
The invention concerns an adjustable armrest for chairs, especially suitable to be applied to office chairs. 
     As it is known, armrests for chairs are formed by an armrest element that is supported by an upright element connected to the seat through appropriate fixing means. 
     Some types of chairs are provided with armrests that are adjustable in height in order to adapt the rest position of the arm according to the user&#39;s needs. 
     The chairs must have a size and a shape in keeping with specific national and/or international sets of rules. 
     There are for example specific sets of rules concerning the distance of the front end of the armrest element as regards the front end of the seat. 
     In particular the regulation ANSI BIFMA prescribes that such distance must not be shorter than 100 mm. 
     Besides the set of rules NEN, in force in Holland, establishes instead for such distance a minimum value of 200 mm. 
     The necessity of respecting these different sets of rules compels the builders to realize the same chair model with the armrests placed at different distances. 
     In order to obtain these conditions, it is necessary to provide on the seat, or anyway in the hooking points of the armrest fixing means, for differentiated perforations, so that the same chair model can receive the same armrest model however fixed in different positions. 
     The aim the present invention is to obviate to the said drawback. 
     In particular an aim of the invention is that of realizing an armrest allowing the chairs equipped with it, to be in keeping with the sets of rules, in force in the different countries, as for the distance of the front end of the armrest element as regards the front end of the seat. 
     The said aim is attained through the realization of a seat for a chair that according to the main claim, includes an upright element substantially vertical provided in the lower part with fixing means to a seat of said chair and supporting in the higher part an armrest element, and wherein said upright element and said armrest element are coupled through sliding means suitable to allow the movement of said armrest element in order to vary the distance of the front end of said armrest element as regards the front end of said seat. 
     According to a preferred embodiment, said sliding means are formed by an annular edge bordering said higher part of said upright element, which is housed slidingly in a guide track obtained inside said armrest element. 
     Suitable locking means allow to fix the armrest element in the reached position. 
     Advantageously the invention allows to standardize the production without providing for differentiated perforations of the seat in order to fix the armrest at different distances as regards the front end of the seat. In such a way the same chair with the same armrests is in conformity with the different sets of rules in force in different countries. 
     Still advantageously the possibility of regulating the position of the armrest can be useful to insert partially the seat under the desk, when its height is lower than the armrest one. 
    
    
     The said aims and advantages will be better underlined during the description of a preferred embodiment of the invention shown approximately but not restrictively referring to the enclosed drawings where: 
     FIG. 1 shows the armrest of the invention in a perspective view; 
     FIG. 2 shows the armrest of FIG. 1 in an exploded perspective view; 
     FIG. 3 shows the armrest of FIG. 1 in a partially sectioned perspective view; 
     FIG. 4 shows the armrest of FIG. 1 in a cross section; 
     FIG. 5 shows the armrest of FIG. 1 in a longitudinal section; 
     FIG. 5A shows alternative embodiment of the arrangement illustrated in FIG.  5 . 
     FIGS. 6 and 7 show the armrest of the invention applied to a chair in two different positions. 
    
    
     As it can be observed in FIG.  1  and also in FIGS. 6 and 7, the armrest, object of the invention and marked with  1  as a whole, includes an upright element  2  substantially vertical provided in the lower part  2   a  with a bracket  3  for fixing a chair S to the seat L and in the higher part  2   b  of an armrest element  4 . 
     According to the invention, the upright element  2  and the armrest element  4  are coupled through sliding means  5  that are suitable to allow the movement of said armrest element  4  in order to vary the distance of the front end  4   a  of said armrest element  4  as regards the front end A of said seat L. 
     According to the preferred embodiment shown and described, later on, the sliding means  5  are formed, as it is underlined also in FIGS. 2 and 3, by an annular edge  6  bordering the higher part  2   b  of said upright element  2 , which is slidingly housed in a guide track  7 , particularly evident in FIG. 4, obtained inside the armrest element  4 . 
     Such guide track  7  is defined between a couple of overhanging longitudinal ribs  8  present inside said armrest element  4  and an annular flange  9  removably coupled to the armrest element  4 . Such annular flange  9  is opposed to the longitudinal ribs  8  and is placed through a beat below said annular edge  6  and therefore is fixed to the armrest element  4  through fixing means that can be, for example, screws  9   a . Suitable locking means, marked with  10  as a whole in FIG. 2, make the armrest element  4  stable in different adjustment positions. 
     Such locking means  10 , as it can be observed also in FIG. 5, include a lever  11  that is inserted between the longitudinal ribs  8 , developing longitudinally to the armrest element  4  and provided at its end with a fulcrum pin  12  and at the opposite end with a move push button  13 , projecting and accessible for the operator. 
     The lever  11  also has a plurality of hollows or slots  14  placed on its length, each one being suitable to house a tooth  15  belonging to the annular edge  6  of said upright element  2 . 
     As an alternative, a plurality of teeth  14 ′ can be placed along the lever  11 , while a slot  15 ″ suitable to cooperate with them, can be formed on the annular edge  6  of the upright element  2 . 
     Between the lever  11  and the armrest element  4  there are elastic means that preferably are formed by an helical spring  16  with a cylindrical section, connected to the move push button  13 . 
     It is evident that the elastic and locking means could be different from the ones that have been shown. 
     Operationally, when the armrest element  4  is rest position, it made to be fixed by the locking means  10 , since the tooth  15  of the annular edge  6  of the upright element  2 , is housed in one of the hollows  14  of the lever  11 . 
     In order to shift it, it is necessary to press the push button  13 , so as to rotate the lever  11  around the fulcrum  12  and lift it until the tooth  15  is unhooked from the respective hollow. 
     After having placed through a sliding the armrest element  4  in the new wanted position, in order to lock it is sufficient to release the push  13  and automatically the lever  11 , pushed by the elastic element  16 , hooks the tooth  15  in the nearest hollow  14 . 
     Different operational positions of the armrest of the invention assembled on a chair S are shown in FIGS. 6 and 7. 
     In particular, in FIG. 6 it can be observed that the armrest element  4  is placed with the end  4   a  in a totally advanced position, while in FIG. 7 it can be observed that the armrest element  4  is placed with the end  4   a  in a totally rear position, corresponding to the shortest distance d and longest distance D as regards the front end A of the seat L. 
     For example, between the shortest distance d and the longest distance D, the shortest distance of 100 mm provided for by the regulation ANSI BIFMA and the shortest distance of 200 mm provided for by the set of rules NEN can be included. 
     The possibility of moving the armrest element  4  allows, besides respecting the distances forced by the different sets of rules, inserting the chair under the desk too, avoiding the interference of the armrest element with the desk. 
     The armrest of the invention can advantageously be provided with further devices, as for example devices suitable to adjust the height of the armrest element as regards the seat plane. 
     As for the materials, the armrest can be built with any type of material according to the particular use it is intended for. 
     According to what has been described it can be understood that the adjustable armrest, object of the invention, attains the prearranged aim. 
     It is intended that the executive variants that have not been shown and described and that could be brought to the armrest of the invention, since they are based on the same claimed resolving idea, are to be considered all protected by the present patent.