Abstract:
An elevating mechanism for furniture installed in a height adjustable article of furniture comprises a transmission unit and a rotary handle. The transmission unit utilizes a plurality of cylindrical gears mounted on respective shafts, whereby the cylindrical gears will be engaged and rotate simultaneously.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to elevating mechanisms for furniture, more particularly to an elevating mechanism for furniture utilizing a plurality of cylindrical gears mounted on respective shafts for a multi-directional motion control.  
       BACKGROUND OF THE INVENTION  
       [0002]     The invention of the prior art disclosed by R.O.C. (Taiwan) patent number 595342 and patent name office desk structure, issued to the applicant, is for adjusting the height of the desk top of an office desk. The invention comprises a desk top, a base frame having a base and a sleeve mount, and a synchronic elevating mechanism installed at a selected place within the desk body. The bolt of the invention is inserted in the sleeve mount of the base frame. The transmission shaft of the invention comprises a bevel gear fro transmission and a bevel gear for elevation. The invention further includes a turning handle for driving the elevating mechanism whereby height adjustment of a desk can be realized.  
         [0003]     The elevating mechanism of the prior art, which utilizes the engagement of a bevel gear fro transmission and a bevel gear for elevation, has the following disadvantages.  
         [0004]     1. The engagement of the bevel gears has a small interface and therefore is easy to collapse.  
         [0005]     2. The combination of the bevel gears may contain an error in the engagement, which will result in noises when operated. It may also cause off-axis of at least one bevel gear and consequently a collapse of the engagement.  
         [0006]     3. The handle is installed at a fixed position, and therefore the operation of the handle may be hindered in a tight space.  
       SUMMARY OF THE INVENTION  
       [0007]     Accordingly, the primary objective of the present invention is to provide an elevating mechanism for furniture utilizes a plurality of cylindrical gears mounted on respective shafts, whereby the cylindrical gears will be engaged and rotate simultaneously. The innovative functions of the elevating mechanism for furniture are listed as follows.  
         [0008]     1. An elevating mechanism for furniture according to the present invention is a combination of cylindrical gears; the engagement of the gear teeth is more secure. Therefore, the transmission unit thereby formed can sustain larger loads without enhancing the material strength of the gears.  
         [0009]     2. The elevating mechanism for furniture comprises three cylindrical gears, and therefore has a stable structure and is immune from misalignment. The assembly of this mechanism to an article of furniture will not produce much noise.  
         [0010]     3. The rotary handle can be applied to several places in the elevating mechanism for furniture, which makes the elevating operation very flexible.  
         [0011]     4. Two sets of the elevating mechanism for furniture can be combined by sharing a common transmission shaft, and therefore the motions of two sets are collateral, allowing a stable elevation for larger articles of furniture.  
         [0012]     The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a perspective view of an elevating mechanism for furniture according to the present invention installed within a table.  
         [0014]      FIG. 2  is an exploded perspective view of the elevating mechanism for furniture in  FIG. 1 .  
         [0015]      FIG. 3  is a perspective view of the elevating mechanism for furniture in  FIG. 1 .  
         [0016]      FIG. 4  is another perspective view of the elevating mechanism for furniture in  FIG. 1 .  
         [0017]      FIG. 5  is a top cross sectional view of the elevating mechanism for furniture in  FIG. 1 .  
         [0018]      FIG. 6  illustrates the elevation of a desk equipped with the elevating mechanism for furniture.  
         [0019]      FIG. 7  is another perspective view of the elevating mechanism for furniture.  
         [0020]      FIG. 8  is an exploded perspective view of the second preferred embodiment of the present invention.  
         [0021]      FIG. 9  is a perspective view of the elevating mechanism for furniture in  FIG. 8 .  
         [0022]      FIG. 10  is another perspective view of the elevating mechanism for furniture in  FIG. 8 .  
         [0023]      FIG. 11  is a top cross sectional view of the elevating mechanism for furniture in  FIG. 8 .  
         [0024]      FIG. 12  illustrates the elevation of a desk equipped with the second preferred embodiment. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]     Referring to  FIGS. 1 and 2 , the first preferred embodiment of the present invention as an elevating mechanism for furniture comprises a transmission unit, a rotary handle  60  and a box  10 . The transmission unit further comprises a bolt  30  vertical to the ground, a first cylindrical gear  31  coaxially secured along a section of the bolt  30 , a nut  20  engaged with a threaded section of the bolt  30 , a horizontal transmission shaft  40  and a second cylindrical gear  41  coaxially secured along a section of the transmission shaft  40  and coupled with the first cylindrical gear  31  of bolt  30 . The top end of the bolt  30  forms a short post  61  with a polygonal cross section, and two ends of the transmission shaft  40  form other two short posts  61  with the same polygonal cross section. The rotary handle  60  is provided with a polygonal hole taking substantially the same shape as the cross section of the short posts  61 . The hole is for receiving either one of the short posts  61  so as to rotate the first cylindrical gear  31  or the second cylindrical gear  41 . The box  10  houses the first cylindrical gear  31  and the second cylindrical gear  41 .  
         [0026]     Referring to  FIGS. 4 and 5 , since the first cylindrical gear  31  and the second cylindrical gear  41  are coupled, the rotation of the transmission shaft  40  will cause the bolt  30  to rotate simultaneously, whereby the rotary handle  60  will activate a rotation of the bolt  30  with respect to the still nut  20  and a upward or downward motion of the article connected to the bolt  30  with respect to the article on which the nut  20  is mounted.  
         [0027]     Referring to  FIG. 7 , two sets of the elevating mechanism for furniture are installed within two table legs  71  of a table so that the height of table top  70  of the table can be adjusted, in which process the table top  70  keeps horizontal. The nut  20  of each elevating mechanism for furniture is secured within a corresponding table leg  71  for receiving the insertion of the bolt  30 ; other parts of the elevating mechanism for furniture is then mounted on the top end of each table leg  71 . The table top  70  is supported by two boxes  10  of two sets of elevating mechanism. Two sets of elevating mechanism share the same transmission shaft  40  so that they move collaterally.  
         [0028]     Referring to  FIG. 12 , the rotary handle  60  is connected to any of the short posts  61 , whereby an external agent can urge a bolt  30  to rotate with respect to the associated nut  20 . Because of the transmission unit, the other bolt  30  will move simultaneously with the bolt  30  being driven; therefore, the other bolt  30  will perform substantially the same rotation with respect to its associated nut  20 . Thereby, two table legs  71  will be changing height at the same time.  
         [0029]     Referring to  FIGS. 8 and 9 , the second preferred embodiment of the present invention as an elevating mechanism for furniture comprises a transmission unit, a rotary handle  60  and a box  10 . The transmission unit further comprises a bolt  30  vertical to the ground, a first cylindrical gear  31  coaxially secured along a section of the bolt  30 , a nut  20  engaged with a threaded section of the bolt  30 , a horizontal first transmission shaft  40 , a second cylindrical gear  41  coaxially secured along a section of the first transmission shaft  40 , a horizontal second transmission shaft  50  and a third cylindrical gear  51  coaxially secured along a section of the second transmission shaft  50 . The second transmission shaft  50  is disposed between the bolt  30  and the transmission shaft  40  and perpendicular to the first transmission shaft  40 , whereby the third cylindrical gear  51  is engaged with both of the first cylindrical gear  31  and the second cylindrical gear  41 . The top end of the bolt  30  forms a short post  61  with a polygonal cross section, and the first transmission shaft  40  and the second transmission shaft  50  each forms two short posts  61  with the same polygonal cross section at either side thereof. The rotary handle  60  is provided with a polygonal hole taking substantially the same shape as the cross section of the short posts  61 . The hole is for receiving either one of the short posts  61  so as to rotate one of the first cylindrical gear  31 , the second cylindrical gear  41  and the third cylindrical gear  51 . The box  10  houses the first cylindrical gear  31  and the third cylindrical gear  51 .  
         [0030]     Referring to  FIGS. 10 and 11 , the rotation of either of the first transmission shaft  40  and the second transmission shaft  50  will drive the bolt  30  to rotate, since the first cylindrical gear  31 , the second cylindrical gear  41  and the third cylindrical gear  51  are coupled. Therefore, with the engagement of the rotary handle  60  and either of the short post  61 s, an elevation of the bolt  30  with respect to the nut  20  can be achieved.  
         [0031]     Referring to  FIG. 7 , two sets of the elevating mechanism for furniture are installed within two table legs  71  of a table so that the height of table top  70  of the table can be adjusted, in which process the table top  70  keeps horizontal. The nut  20  of each elevating mechanism for furniture is secured within a corresponding table leg  71  for receiving the insertion of the bolt  30 ; other parts of the elevating mechanism for furniture is then mounted on the top end of each table leg  71 . The table top  70  is supported by two boxes  10  of two sets of elevating mechanism. Two sets of elevating mechanism share the same transmission shaft  40  so that they move collaterally.  
         [0032]     Referring to  FIG. 12 , the rotary handle  60  is connected to any of the short posts  61 , whereby an external agent can urge a bolt  30  to rotate with respect to the associated nut  20 . Because of the transmission unit, the other bolt  30  will move simultaneously with the bolt  30  being driven; therefore, the other bolt  30  will perform substantially the same rotation with respect to its associated nut  20 . Thereby, two table legs  71  will be changing height at the same time.  
         [0033]     The present invention is thus described, and it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.