Auxiliary Support Installed onto Chair Armrest

Abstract

An auxiliary support to be installed onto a chair armrest is disclosed. The auxiliary support includes a first adjusting arm that is able to pivot up and down and has one end formed as a rotating end that is vertically connected to a connecting end of the armrest, a second adjusting arm that is able to pivot up and down and forward and backward and has one end formed as a rotating end that is transversely connected to a connecting end at an opposite end of the first adjusting arm, and a supporting tray that is connected to an opposite end of the second adjusting arm and is adjustably inclinable for supporting a portable device (e.g. a tablet computer or a book). Thereby, a user sitting in the chair can put the portable device on the auxiliary support and operate it comfortably.

What is claimed is: 
     
         1 . An auxiliary support to be attached to an outer side of a vertically adjustable chair armrest, the auxiliary support comprising a first adjusting arm that is able to pivot up and down and has one end formed as a rotating end that is vertically connected to a connecting end of the armrest, a second adjusting arm that is able to pivot up and down and forward and backward and has one end formed as a rotating end that is transversely connected to a connecting end at an opposite end of the first adjusting arm, and a supporting tray that is connected to an opposite end of the second adjusting arm and is adjustably inclinable. 
     
     
         2 . The supporting device of  claim 1 , wherein the connecting end of the first adjusting arm and the rotating end of the second adjusting arm are connected by a connecting member, the connecting member having one end formed as a rotating end and an opposite end formed as a connecting end, a rotatable positioning unit being provided between the rotating end of the connecting member and the connecting end of the first adjusting arm, and another rotatable positioning unit being provided between the connecting end of the connecting member and the rotating end of the second adjusting arm. 
     
     
         3 . The supporting device of  claim 1 , wherein a rotatable positioning unit is provided between the rotating end of the first adjusting arm and the connecting end of the armrest. 
     
     
         4 . The supporting device of  claim 2 , wherein the rotatable positioning unit comprises a guiding portion that is formed centrally in the connecting end and is for receiving a toothed member pushed outward by a spring, the connecting end and the toothed member both annularly formed with teeth to always engage with each other, the rotating end also having teeth for engaging with the teeth of the toothed member, a fastening member pivotally fastening the rotating end to the connecting end, and a pushbutton having a plurality of pins being attached to an outer side of the rotating end, so that the pins pass through the rotating end and abut against the toothed member, thereby pushing the toothed member to move and making the teeth of the toothed member and the teeth of the rotating end disengage from or engage with each other. 
     
     
         5 . The supporting device of  claim 4 , wherein the connecting end has an outer periphery thereof formed with a limiting recess for providing a predetermined angular range, and the rotating end has a retaining portion to be received in the limiting recess. 
     
     
         6 . The supporting device of  claim 1 , wherein the supporting tray has a lower edge thereof provided with a lower retaining portion, and two lateral retainers are slidably attached a lower surface of the supporting tray so as to be expanded and retracted with respect to two sides of the supporting tray, in which each said lateral retainer has an outer end provided with a holding portion. 
     
     
         7 . The supporting device of  claim 6 , wherein a stationary case is attached to an outer side of the lower retaining portion of the supporting tray. 
     
     
         8 . The supporting device of  claim 6 , wherein each of the lateral retainers has two legs for passing through two through holes formed on the supporting tray and being slidably received in two channels formed at the lower surface of the supporting tray and covered by a covering plate, and each of the two legs is terminated with an inward bent hook portion that is to be retained by a stop portion formed in the channel. 
     
     
         9 . The supporting device of  claim 8 , wherein each of the channels is partially narrowed to provide a narrowed segment for closely fitting the corresponding leg. 
     
     
         10 . The supporting device of  claim 1 , wherein the second adjusting arm has a terminal thereof fixedly connected to a spherical joint that has a ball part, and a universal unit corresponding to the supporting tray is provided to receive the ball part. 
     
     
         11 . The supporting device of  claim 10 , wherein the spherical joint has a lower end thereof provided with a fixing portion to be fixedly connected with the connecting seat at the terminal of the second adjusting arm, the fixing portion has an upper end thereof formed as the ball part, and the universal unit comprising a lower hemispherical recess formed on the supporting tray and a combining member that is fixed to the supporting tray and has a lower surface thereof formed with an upper hemispherical recess so that the ball part is received between the upper and lower hemispherical recesses. 
     
     
         12 . The supporting device of  claim 11 , wherein a raised retaining portion that is formed like a continuous circle near a top of the ball part and defines therein moving area, while two symmetrical raised retaining portions are formed at two sides of a ceiling of the upper hemispherical recess so that the two raised retaining portions are received in the moving area. 
     
     
         13 . The supporting device of  claim 11 , a notch is formed in the lower hemispherical recess of the supporting tray for receiving a pushed member, and a pushing element is screwed into the supporting tray corresponding to the pushed member, so that the pushed member is pressed by the pushing element to tightly abut against the ball part. 
     
     
         14 . The supporting device of  claim 3 , wherein the rotatable positioning unit comprises a guiding portion that is formed centrally in the connecting end and is for receiving a toothed member pushed outward by a spring, the connecting end and the toothed member both annularly formed with teeth to always engage with each other, the rotating end also having teeth for engaging with the teeth of the toothed member, a fastening member pivotally fastening the rotating end to the connecting end, and a pushbutton having a plurality of pins being attached to an outer side of the rotating end, so that the pins pass through the rotating end and abut against the toothed member, thereby pushing the toothed member to move and making the teeth of the toothed member and the teeth of the rotating end disengage from or engage with each other. 
     
     
         15 . The supporting device of  claim 14 , wherein the connecting end has an outer periphery thereof formed with a limiting recess for providing a predetermined angular range, and the rotating end has a retaining portion to be received in the limiting recess.