Abstract:
An adjustable armrest assembly comprises a supporting tube having a chamber and a plurality of positioning grooves formed within the chamber, and a height control member slidably engaged along the chamber of the supporting tube; the height control member is connected to a armrest and provided with a positioning block, wherein the positioning block can be selectively driven to disengage from or engage with any one of the positioning grooves such that the armrest can be adjusted and fixed to a desirable height.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention generally relates to an armrest assembly, and more particularly to an adjustable armrest assembly.  
         [0003]     2. Description of the Related Art  
         [0004]      FIGS. 1 and 2  show a conventional adjustable armrest assembly  10 . The adjustable armrest assembly  10  comprises an L-shaped supporting member  12 , a vertical sleeve  14 , a lever body  16 , and an armrest  18 .  
         [0005]     The L-shaped supporting member  12  has a horizontal part  20  fixed on a chair (not shown), and a vertical part  22  extending upward from the proximal end of the horizontal part  20  and having a plurality of positioning grooves  24  formed thereon. The vertical sleeve  14  is slidably sleeved on the vertical part  22  and defines a space  26  for receiving the vertical part  22 . The vertical sleeve  14  has a plurality of limiting ribs  28  formed within the space  26 , and the limiting ribs  28  slidably contact the vertical part  22  so as to prevent wobbling of the vertical sleeve  14  relative to the vertical part  22 . The lever body  16  has an upper block portion  30  pivoted to the vertical sleeve  14 , an engaging portion  32  extending downward from the upper block portion  30  into the space  26  to releasably engage one of the positioning grooves  24 , and an operating portion  34  connected to the upper block portion  30  and exposed from the vertical sleeve  14 . The armrest  18  is disposed on the vertical sleeve  14 .  
         [0006]     When the operating portion  34  is lifted upward as shown in  FIG. 2 , the engaging portion  32  disengages from the positioning groove  24  and then selectively engages with any other positioning groove  24  such that the armrest  18  can be adjusted to a suitable and desired height.  
         [0007]     However, the engaging portion  32  may disengage from the selected positioning groove  24  due to an unexpected touch at the operating portion  34 , such that the user needs to reset the armrest  18  to the suitable height. In addition, it is relatively inconvenient and laborious to operate and assemble the armrest assembly  10 .  
         [0008]     Accordingly, the present invention provides an adjustable armrest assembly to overcome the above-mentioned problems.  
       SUMMARY OF THE INVENTION  
       [0009]     It is an object of the present invention to provide an adjustable armrest assembly, which can be conveniently operated and assembled.  
         [0010]     It is another object of the present invention to provide an adjustable armrest assembly, in which an armrest can be easily and quickly adjusted to a suitable and desired height.  
         [0011]     In order to achieve the above object, the present invention provides an adjustable armrest assembly, which comprises a supporting tube having a chamber and a plurality of positioning grooves formed within the chamber, and a height control member slidably engaged along the chamber of the supporting tube; wherein the height control member comprises a first controlling part having a first end defining a fixing slot and a second end for being connected to an armrest, and a second controlling part having a first end provided with a positioning block movably embedded in the fixing slot of the first controlling part.  
         [0012]     According to the adjustable armrest assembly of the present invention, the second controlling part is coupled with the first controlling part and movable relative to the first controlling part between an engaging position and a disengaging position; wherein the positioning block is driven to eject from the fixing slot and engage with one of the positioning grooves while the second controlling part is moved to the engaging position, and the positioning block is driven to draw back into the fixing slot and disengage from each of the positioning grooves while the second controlling part is moved to the disengaging position.  
         [0013]     The adjustable armrest assembly according to the present invention further comprises a rotatable indicator, which is attached to the height control member and rotatable according to the sliding position of the height control member relative to the supporting tube whereby showing the height of the armrest relative to the supporting tube. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     Other objects, advantages, and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.  
         [0015]      FIGS. 1 and 2  show a conventional adjustable armrest assembly.  
         [0016]      FIG. 3  is an exploded view of an adjustable armrest assembly according to one embodiment of the present invention.  
         [0017]      FIG. 4  is a perspective view of the guiding frame of the supporting tube according to the present invention.  
         [0018]      FIG. 5  is a cross-sectional view of the adjustable armrest assembly according to the present invention, in which the second controlling part is moved to an engaging position.  
         [0019]      FIG. 6  is a cross-sectional view of the adjustable armrest assembly according to the present invention, in which the second controlling part is moved to a disengaging position.  
         [0020]      FIG. 7  is another cross-sectional view of the adjustable armrest assembly according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]      FIG. 3  is an exploded view of an adjustable armrest assembly  100  according to one embodiment of the present invention. The armrest assembly  100  comprises a supporting tube  102 , a height control member  104  and a housing  106 . The supporting tube  102  is fixed on one side of a chair (not shown) and defines a chamber  108  for receiving the height control member  104 . The height control member  104  is slidably engaged along the chamber  108  of the supporting tube  102 . The housing  106  houses the supporting tube  102  and the height control member  104 , and has an opening  109   a  and an opening  109   b  respectively formed on two opposite sides. In addition, the housing  106  and the height control member  104  are slidable together relative to the supporting tube  102 . The supporting tube  102  has a guiding frame  110  fixed on the inner wall  108   a  of the chamber  108  for guiding the height control member  104  into the chamber  108 . The guiding frame  110  has a plurality of positioning grooves  112  arranged in a row along one of its inner surfaces and a rack gear  114  provided along another one of its inner surfaces as shown in  FIG. 4 . The guiding frame  110  further has a receiving slit  110   a  formed thereof.  
         [0022]     The height control member  104  includes a first controlling part  116  and a second controlling part  118  coupled with the first controlling part  116 . The first controlling part  116  has a guide gear  120 , three transmission gears  122 ,  124 ,  126 , and a driving gear  128 , which are rotatably installed on the side  129   a  through four fixed pins  130   a,    130   b,    130   c,    130   d  and a rotatable pin  132 , respectively. The guide gear  120  is engaged with the rack gear  114  and rotatably travels along the rack gear  114  such that the height control member  104  is slidably engaged along the chamber  108  of the supporting tube  102 . A fixing element  134  is coupled to the four fixed pins  130   a,    130   b,    130   c,    130   d  and the rotatable pin  132  and fixed to the side  129   a  through two screws  136  such that the guide gear  120 , the three transmission gears  122 ,  124 ,  126 , and the driving gear  128  can be rotatably fixed between the fixing element  134  and the side  129   a  of the first controlling part  116 .  
         [0023]     The fixed pins  130   a,    130   b,    130   c,    130   d  are integrally formed on the side  129   a.  The rotatable pin  132  is rotatably mounted on the side  129   a  and engaged with the driving gear  128 , such that the rotatable pin  132  can rotate in accordance with the rotation of the driving gear  128 . The rotatable pin  132  passes through a hole  138  formed on the fixing element  134  and connected to a rotatable indicator  140 . The rotatable indicator  140  is disposed at the opening  109   a  of the housing  106  and has several different numerals  142  marked around the surface  140   a.  The supporting tube  102  further has a receiving slit  111  corresponding to the receiving slit  110   a  of the guiding frame  110  for receiving the rotatable pin  132 .  
         [0024]     In addition, the first controlling part  116  has one end  116   a,  which defines a fixing slot  144  and a receiving slot  146  across the fixing slot  144 . The first controlling part  116  further has one end  116   b,  which is provided with a supporting plate  147  for being connected to an armrest (not shown). The supporting plate  147  has four fixing holes  147   a  formed thereof and respectively corresponding to four screw holes  106   a  formed on the housing  106 . Four screws (not show) can pass through the four fixing holes  147   a  of the supporting plate  147  and screw into the four screw holes  106   a  of the housing  106 , respectively, such that the first controlling part  116  can be firmly fixed to the housing  106 . The second controlling part  118  has one end  118   a,  which includes a bent portion  148  and is provided with a positioning block  150  having an opening  150   a  defined thereon. The bent portion  148  includes an upper segment  148   a,  a lower segment  148   b,  and a shifting segment  148   c  therebetween, and passes through the opening  150   a  such that the positioning block  150  can slide along the segment  148   a,    148   b  and  148   c.  The second controlling part  118  is coupled with the first controlling part  116  on the side  129   b,  such that the positioning block  150  is embedded and movable horizontally in the fixing slot  144  while the bent portion  148  is positioned and movable vertically within the receiving slot  146 . The second controlling part  118  further has one end  118   b  provided with an operating element  152 , and the operating element  152  is attached to the end  118   b  of the second controlling part  118  while passing through the opening  109   b  of the housing  106 .  
         [0025]     The first controlling part  116  has a groove  154  formed on the side  129   b,  and the second controlling part  118  has a groove  156  formed corresponding to the groove  154  of the first controlling part  116 . The groove  154  of the first controlling part  116  and the groove  156  of the second controlling part  118  together define a spring chamber  158  for accommodating a spring  160 .  
         [0026]     Now referring to  FIG. 5 , the spring  160  applies an elastic force E to a side surface  156   a  of second controlling part  118  such that the second controlling part  118  is moved to an engaging position, in which the bottom surface  118   d  of the second controlling part  118  contacts and stops at the positioning block  150 . When the second controlling part  118  is moved to the engaging position, the bent portion  148  is moved downward and drives the positioning block  150  to the upper segment  148   a  such that the positioning block  150  ejects from the fixing slot  144  and engages with one of the positioning grooves  112 .  
         [0027]     Now referring to  FIG. 6 , when the armrest (not shown) connected to the supporting plate  147  is required to be adjusted to a desired height relative to the supporting tube  102 , the operating element  152  is lifted upward by the user with an applying force F opposing the elastic force E such that the second controlling part  118  is moved to a disengaging position, in which the top surface  118   c  of the second controlling part  118  contacts and stops at the bottom  147   b  of the supporting plate  147 . When the second controlling part  118  is moved to the disengaging position, the bent portion  148  is moved upward and drives the positioning block  150  to the lower segment  148   b  such that the positioning block  150  draws back into the fixing slot  144  and disengages from the one of the positioning grooves  112 . When the positioning block  150  disengages from the one of the positioning grooves  112 , the guide gear  120  can rotatably travel along the rack gear  114  (as shown in  FIG. 7 ) such that the height control member  104  is movable relative to the supporting tube  102 ; that is, the armrest (not shown) is movable relative to the supporting tube  102 . When the armrest (not shown) is moved/adjusted to the desired height relative to the supporting tube  102 , the applying force F can be released such that the second controlling part  118  is returned to the engaging position by the elastic force E; meanwhile, the positioning block  150  ejects from the fixing slot  144  again and engages with a selected positioning groove  112 .  
         [0028]     Now referring to  FIGS. 1 and 7 , the guide gear  120  is engaged with the first transmission gear  122 , the first transmission gear  122  is engaged with the second transmission gear  124 , and the second transmission gear  124  is engaged with the third transmission gear  126 . The third transmission gear  126  has a concentric pinion gear  127  integrally formed thereon and engaged with the driving gear  128 . When the positioning block  150  disengages from the one of the positioning grooves  112 , the guide gear  120  can rotatably travel along the rack gear  114  and drive the transmission gears  122 ,  124 ,  126  and the driving gear  128  to rotate simultaneously. In another word, the transmission gears  122 ,  124 ,  126  and the driving gear  128  rotate in accordance with the rotation of the guide gear  120 . As noted above, there are three transmission gears  122 ,  124 ,  126  in this embodiment. It should be appreciated that the number of the transmission gears mainly depends on the stroke of the adjustable height. The longer the stroke is, the more transmission gears are required.  
         [0029]     According to the armrest assembly  100  of the present invention, the rotatable indicator  140  can rotate in accordance with the rotation of the guide gear  120  since it is connected to the rotatable pin  132  engaged with the driving gear  128 . Further, the peripheral surface around the opening  109   a  of the housing  106  is marked with at least a sign, e.g. an arrow  162  as shown in  FIG. 3 . When the guide gear  120  travels along the rack gear  114 , that is, the height control member  104  is moved relative to the supporting tube  102 , the rotatable indicator  140  rotates at the opening  109   a  in accordance with the rotation of the guide gear  120  such that the numerals  142  is moved relative to the arrow  162 . In this manner, the position of the height control member  104  relative to the supporting tube  102 , i.e. the height of the armrest (not shown) relative to the supporting tube  102 , can be presented/indicated while the numerals  142  is pointed by the arrow  162 .  
         [0030]     Although the invention has been explained in relation to its preferred embodiment, it is not used to limit the invention. It is to be understood that many other possible modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the invention as hereinafter claimed.