Patent Publication Number: US-10765218-B2

Title: Chair or armchair with adjustable backrest

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is the 35 U.S.C. § 371 national stage application of PCT Application No. PCT/IB2017/053036, filed May 23, 2017, where the PCT claims the priority to and benefit of Italian Patent Application No. 102016000053316, filed May 24, 2016, both of which are herein incorporated by reference in their entireties. 
     The object of the present invention is a chair or armchair, of the type provided with an adjustable backrest. 
     As is known, there are jobs that require the worker to sit for hours, sometimes in limited spaces. For example, one might think of a cashier in a supermarket sitting during the hours of the shift, but constantly moving towards the conveyor belt during code scanning operations for products, sometimes heavy ones, and then toward the cash register during payment operations. 
     It is therefore essential to provide workers with a comfortable seat and proper posture, first of all in order to safeguard their health, but also in terms of better working performance, linked to personal wellbeing. 
     For this reason, there are countless chairs with adjustable seating options that are more or less effective, such as seat height, backrest height and/or inclination. 
     In the specific case of the chairs provided with an adjustable inclination backrest, the Applicant has found that in the different angular positions of the backrest, the worker&#39;s back support is not always optimal. 
     The object of the present invention is to provide a chair or armchair with adjustable backrest that meets the above requirements and overcomes the disadvantages of the known art. 
     Such object is achieved by a chair according to claim  1 . The dependent claims describe further embodiments of the invention. 
    
    
     
       The features and advantages of the chair according to the present invention will be apparent from the description given below, provided by way of non-limiting example, in accordance with the appended figures, wherein: 
         FIG. 1  shows a chair assembly according to an embodiment of the present invention, with the backrest in a raised limit configuration; 
         FIG. 2  shows the chair assembly of  FIG. 1 , with the backrest in a lowered limit configuration; 
         FIG. 3  illustrates a cross-sectional view of the chair assembly with the backrest in an advanced limit position; 
         FIG. 4  illustrates a cross-sectional view of the chair assembly with the backrest in an intermediate position; 
         FIG. 5  illustrates a cross-sectional view of the chair assembly, with the backrest in a retracted limit position; and 
         FIG. 6  is an overall view of a locking and adjusting device of the chair assembly according to an embodiment of the invention. 
     
    
    
     With reference to the accompanying figures, at  1  is collectively indicated a chair assembly, suitable to be applied to a support and a base, and possibly provided with armrests, to constitute a chair or an armchair. 
     The chair assembly  1  comprises a seat consisting of a suitably shaped seat body  2 , provided with an upper face  2   a  and a lower face  2   b , and padding (not shown) applied to the seat body  2 . 
     The chair assembly  1  further comprises a locking and adjusting device  4 , applied to the lower face  2   b  of the seat body  2 . 
     Furthermore, the chair assembly  1  comprises a backrest consisting of a backrest body  6 , provided with a front face  6   a  and a rear face  6   b , and has padding (not shown) applied to the backrest body  6 . 
     The chair assembly  1  further comprises a back support  10  which connects the locking and adjusting device  4  to the backrest body  6  to support it at the desired height and angular position. 
     The back support  10  comprises a lower engagement portion  12  attached to the seat body  2 , for example part of the locking and adjusting device  4 , and an upper engagement portion  14  attached to the backrest body  6  which, for example, forms a support element for the backrest body  6 . 
     The backrest support  10  further comprises a first arm  16  or rear arm, hinged to the lower engagement portion  12  in a first lower axis  18 , and a second arm  20  or anterior arm, hinged to the lower engagement portion  12  in a second lower axis  22 , preferably distinct from and parallel to the first lower axis  18 . 
     Moreover, the first arm  16  is hinged to the upper engagement portion  14  in a first upper axis  24 , and the second arm  20  is hinged to the upper engagement portion  14  in a second upper axis  26 , also separate and distinct from each other. 
     The lower engagement portion  12 , the upper engagement portion  14 , the first arm  16 , and the second arm  20 , together, provide an articulated parallelogram that allows the backrest body  6  to be positioned angularly causing it to always remain parallel to itself. 
     Advantageously, this makes it possible to place the backrest in different positions, in a way, however, that always provides the most suitable surface for the back so as to have optimal contact and support. 
     This is evident from the sequence of  FIGS. 3, 4 and 5 : in  FIG. 3 , the backrest support  10  is in the upper limit position, i.e. where the backrest has the greatest overlap to the seat; in  FIG. 4 , the backrest support  10  is in an intermediate position; in  FIG. 5 , the backrest support  10  is in the retracted limit position, i.e. the one in which the backrest has the least overlap with the seat. In all the positions of the backrest support  10 , however, the backrest body  6  is parallel to itself. 
     The backrest support  10  comprises return means suitable to operate permanently to bring the backrest support  10  towards a retracted limit position. 
     Said return means are elastic and comprise at least one spring  30 , or equivalent component, operating on one of said arms  16 ,  20 , for example on the first arm  16 . 
     Said spring  30 , permanently in traction, is fastened to the first arm  16  at a first coupling point  32  and further coupled to a fixed stop, for example on the lower engagement portion  12 , in a second coupling point  34 . 
     Preferably, the second coupling point  34  coincides with the second lower axis  22 . 
     Preferably, furthermore, the second coupling point  34  is separate and distinct from the first lower axis  18 , and preferably placed below the same. 
     Preferably, furthermore, the first arm  16  has an extension  40  opposite to the end linked with the upper engagement portion  14  relative to the first lower axis  18 ; said extension  40  is hinged to a main bar  50  of the locking and adjusting device  4  in a locking axis  42 . 
     Defining a longer length L, such as the distance between the first lower axis  18  and the first upper axis  24 , and a shorter length  1 , such as the distance between the locking axis  42  and the first lower axis  18 , the L/1 characteristic ratio is preferably between 3 and 6, more preferably between 4 and 5, and preferably equal to 4.7. 
     Preferably, furthermore, the first coupling point  32 , to which the spring  30  is coupled, is located between the locking axis  42  and the first lower axis  18 . 
     Preferably, furthermore, the first arm  16  and the second arm  20  also have an arched, frontally concave trend, that is, towards the seat, to optimize the position of the backrest relative to the seat. This is particularly advantageous, moreover, in the advanced limit position of the backrest support. 
     The locking and adjusting device  4  preferably comprises a main body  60  constituted by a central portion extending longitudinally from a front end  62   a  to a rear end  62   b , and a plurality of wings protruding transversely on one side and on the other of the central portion  62 . Said wings are suitable for the mechanical connection of the main body  60  to the seat body  2  of the seat, and for the attachment of any armrests. 
     For example, the main body  60  has a pair of front wings  64  and a pair of rear wings  66 . 
     Preferably, furthermore, the lower engagement portion  12  protrudes behind the central portion  62 . 
     The locking and adjusting device  4  comprises locking means suitable to lock the backrest support  10  in a desired angular position. 
     Said locking means comprise the main bar  50 , extending predominantly along a bar axis Z, a locking element  52 , and a release lever  54 . 
     The block element  52  is hinged to the central portion of the main body  60  in a secondary axis  56  and is provided with a through-hole  57  having a predefined hole axis; the main bar  50  crosses the block element  52  through said hole  57 , dimensionally with radial play. 
     Preferably, furthermore, said locking element  52  is housed in a compartment  58  made in said central portion  62 . 
     Preferably, the locking element  52  comprises a block plate  52   a , provided with a hole  57 , and an engagement flap  52   b  protruding from the locking plate  52   a  and suitable to engage with the release lever  54  to cause the rotation of the locking element  52  around the secondary axis  56 . 
     The release lever  54 , engageable with the locking element  52 , is also hinged to the central portion  62  of the main body  60  and protrudes transversely between two wings  64 ,  66  so that it may be actuated by a user, by placing his/her hand under the seat. 
     In a rest configuration, the main bar  50  has a predefined position, which corresponds to a predefined angular position of the backrest support. For example, the chair assembly is in an intermediate configuration ( FIG. 4 ). 
     In this rest configuration, the hole axis  57  is incident to the bar axis Z of the main bar  50 , by virtue of the play between the bar and the hole  57 . 
     Consequently, the main bar  50  is frictionally engaged in the hole  57  and therefore maintains its predefined position. 
     Consequently, since the main bar  50  is engaged with the backrest support  10 , and in particular hinged to the first arm  16 , also said backrest support is maintained in the predefined angular position. 
     If, from the rest configuration described above, the user, typically remaining seated, acts on the backrest by pulling it or pushing it toward the advanced limit position, the action exerted on the main bar  50  is transmitted to the locking element  52  by pulling it back, i.e. such that the hole axis  57  tends to align with the axis bar Z until the main bar  50  undergoes a translation, creeping into the hole  57  of said block element  52 . 
     When the wearer&#39;s action on the backrest ends, the same remains in the new position, since the main bar  50 , under the counter action of the return means, re-engages in the locking element  52 . 
     If, instead of the rest configuration described above, the user, typically remaining seated, acts on the backrest by pulling it or pushing it toward the retracted limit position, the action exerted on the main bar  50  is transmitted to the locking element  52  by pushing it forward, i.e. such that the hole axis  57  tends to misalign with the axis bar Z; the main bar  50  engages therefore deeper into the hole  57  and does not undergo any translation. 
     Advantageously, this allows the user to quickly adjust the position of the backrest so that it is well positioned against the back. 
     In particular, the user, remaining seated, may bring both hands behind the backrest and push it toward the advanced limit position, thus adjusting it optimally. If, on the other hand, the user rests his/her back on the backrest and pushes it, the same does not change its position. 
     From the rest configuration, the actuation of the release lever  54  causes a rotation of the locking element  52  in the direction of aligning the hole axis  57  with the bar axis Z, thus allowing the sudden and free sliding of the main bar  50  into the locking element  52 , under the action of the spring  30 . 
     Consequently, the backrest support is released and is brought abruptly to the retracted limit position under the action of the return means. 
     Advantageously, this allows the user to release the back support by means of the release lever  50 , avoiding blows to the back, since the backrest is brought back to the retracted limit position. 
     According to a preferred embodiment, the locking and adjusting device  4  further comprises a lever  70  for operating the seat&#39;s vertical adjustment means. 
     Said auxiliary lever  70  preferably protrudes transversely from the central portion  62  of the main body  60 , from the opposite side relative to the release lever  50 , and ends at the mouth of a vertical adjustment hole  72  through the central portion  62 . 
     The seat&#39;s vertical adjustment means typically comprise a gas piston, intended to be inserted through the vertical adjustment hole  72 , being thus engageable by the additional lever  70 . 
     According to a preferred embodiment, furthermore, the chair assembly  1  also comprises backrest vertical adjustment means for adjusting the vertical position of the backrest. 
     For example, said backrest vertical adjustment means comprise said upper engagement portion  14 , in which the backrest body  6  is slidably engaged, directly or indirectly. 
     For example, said upper engagement portion  14  comprises a plate  80  slidably inserted in guides  82  formed in an auxiliary plate  84  applied to the rear face  6   b  of the backrest body  6  or directly in the rear face of the backrest body  6 . 
     Innovatively, the chair assembly described above allows the disadvantages of the prior art to be overcome, since it allows the optimal backrest position for the user to be maintained in any angular position of the backrest. 
     Advantageously, furthermore, the user, while remaining seated, may use both hands to operate the backrest, since it is not necessary to release any locking device. 
     According to an equivalent embodiment, the second arm of the backrest support is engaged with the main bar of the locking means. 
     According to a further embodiment, the spring of the return means is placed between the second arm and a fixed corresponding part. 
     Such variants are also contained within the scope of protection as defined by the following claims.