Abstract:
An adjustable-height stand that attaches to a device and allows for rough and fine adjustment of the height of the device. The stand has a screw rod, an adjusting mechanism, and a supporting mechanism. The supporting mechanism attaches to the device. The adjusting mechanism is connected to the supporting mechanism and the screw rod and has two states. In the fine adjustment state, the height is adjusted by turning the screw rod. In the rough adjustment state, the contact between the screw rod and the adjusting mechanism can be broken so that the supporting mechanism can slide up and down the length of the screw rod without turning the screw rod.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an adjustable-height stand. More specifically, the present invention discloses a stand with fine adjustment and rough adjustment functions.  
           [0003]    2. Description of the Prior Art  
           [0004]    In a common projector or a related product, an adjustable-height stand is used to adjust the height or angle of elevation of the projector to aim an image onto a screen or wall. Therefore, designing an easy-to-use adjustable-height stand is an important goal for designers.  
           [0005]    Please refer to FIG. 1 FIG. 1 is a structural diagram of a stand  10  of a prior art projector. The stand  10  is used to support a projector  12 . As shown in FIG. 1, the stand  10  of the prior art projector comprises a screw rod  14 , and an adjusting mechanism  16  for supporting the projector  12 . The adjusting mechanism  16  comprises a screw hole  18  through which it is installed on the screw rod  14 . Users rotate the screw rod  14  to drive the adjusting mechanism  16  up and down so as to adjust the height or the angle of elevation of the projector.  
           [0006]    However, the design of the stand of the prior art projector is inconvenient for large adjustments. To make an adjustment to the height of the adjusting mechanism  16 , users must rotate the screw rod  14  until the adjusting mechanism  16  is at the desired height. For small adjustments, this is a fairly quick operation, but large adjustments can take a long time, as there is no quick way to change the height of the adjusting mechanism  16 . In other words, the stand  10  of the prior art projector has a fine adjustment function but does not have a rough adjustment function.  
         SUMMARY OF INVENTION  
         [0007]    It is therefore a primary objective of this invention to provide a stand that has both fine adjustment and rough adjustment functions.  
           [0008]    The claimed invention, briefly summarized, discloses a stand for supporting a predetermined device. The stand comprises a screw rod, a supporting mechanism, and an adjusting mechanism. The supporting mechanism supports the predetermined device. The adjusting mechanism is installed on the screw rod and connected to the supporting mechanism for adjusting the height of the supporting mechanism. The adjusting mechanism comprises a hole portion through which the adjusting mechanism is installed on the screw rod. The hole portion comprises an upper U-shaped wall and a lower U-shaped wall. The upper U-shaped wall is positioned on a front-upper region of the hole portion, the upper U-shaped wall having a first screw thread. The lower U-shaped wall is positioned on a back-lower region of the hole portion, the lower U-shaped wall having a second screw thread. The upper and lower U-shaped walls are positioned opposite each other and can separate from the screw rod. When the upper and lower U-shaped walls contact with the screw rod, the adjusting mechanism is moved up and down by rotating the screw rod, and when the upper and lower U-shaped walls separate from the screw rod, the adjusting mechanism is capable of sliding along the screw rod.  
           [0009]    It is an advantage of the claimed invention that the adjusting mechanism can tilt at an angle in order to separate from the screw rod. This allows the supporting mechanism to slide along the screw rod. The claimed invention stand provides both fine adjustment and rough adjustment functions.  
           [0010]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0011]    [0011]FIG. 1 is a structural diagram of a stand of a prior art projector.  
         [0012]    [0012]FIG. 2 is an assembly diagram of a stand according to the present invention.  
         [0013]    [0013]FIG. 3 is a component diagram of the stand shown in FIG. 2.  
         [0014]    [0014]FIG. 4 is a structural diagram of the adjusting mechanism shown in FIG. 3.  
         [0015]    [0015]FIG. 5 and FIG. 6 are operational diagrams of the stand in FIG. 2.  
         [0016]    [0016]FIG. 7 and FIG. 8 are operational diagrams of another stand according to the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0017]    Please refer to FIG. 2 and FIG. 3. FIG. 2 is an assembly diagram of a stand  30  according to the present invention. FIG. 3 is a component diagram of the stand  30  shown in FIG. 2. The stand  30  is used to support a predetermined device (such as projector, etc.)  31  and to adjust the height or the angle of elevation of the predetermined device. As shown in FIG. 2 and FIG. 3, the stand  30  comprises a screw rod  32 , a supporting mechanism  34  installed on the screw rod  32  for supporting the predetermined device  31 , an adjusting mechanism  36  installed on the screw rod  32  and connected to the supporting mechanism  34  for adjusting the height of the supporting mechanism  34 , a key portion  38  positioned on the adjusting mechanism  36 , and a spring  40  installed between the supporting mechanism  34  and the adjusting mechanism  36 . The supporting mechanism  34  comprises an upper housing  42  and a lower housing  44 . The stand  30  further comprises a base  46  installed on the bottom side of the screw rod  32  with which users can rotate the screw rod  32 .  
         [0018]    Please refer to FIG. 4. FIG. 4 is a structural diagram of the adjusting mechanism  36  shown in FIG. 3. As shown in FIG. 4, the adjusting mechanism  36  comprises a hole portion  48 . The adjusting mechanism  36  is installed on the screw rod  32  through the hole portion  48 . The hole portion  48  comprises an upper U-shaped wall  50  positioned on a front-upper region (left region of FIG. 4) of the hole portion  48 , and a lower U-shaped wall  52  positioned on a back-lower region (right region of FIG. 4) of the hole portion  48 , opposite to the upper U-shaped wall  50 . The upper and lower U-shaped walls  50 ,  52  have a first screw thread  50   a  and a second screw thread  52   a,  respectively, which mate with the screw rod  32 . This design of the hole portion  48  is able to make the adjusting mechanism  36  tilt at a certain angle over the screw rod  32 , causing the upper and lower U-shaped walls  50 ,  52  to separate from the screw rod  32 . FIG. 5 and FIG. 6 will illustrate this operation in detail.  
         [0019]    The adjusting mechanism  36  can rotate on an axis  54  and connect with the supporting mechanism  34 . The axis  54  is perpendicular to the screw rod  32 . The axis  54  and the lower U-shaped wall  52  are on the same side of the hole portion  48  (left side of the hole portion shown in FIG. 4). The adjusting mechanism  36  further comprises two axles  56  installed on the axis  54 , and the supporting mechanism  34  comprises the corresponding hole  58  (formed by the upper and lower housing  42 ,  44 , please refer to FIG. 3) for engaging with the axle so that the adjusting mechanism  36  can rotate over the supporting mechanism  34 .  
         [0020]    Please refer to FIG. 5 and FIG. 6. FIG. 5 and FIG. 6 are operational diagrams of the stand  30 . FIG. 5 shows that the stand  30  is in a steady and fine-adjustable state. As shown in FIG. 5, when users do not depress the key portion  38 , the spring  40  will exert pressure on the left side of the adjusting mechanism  36  so that the upper and lower U-shaped walls  50 ,  52  contact the screw rod  32 . In this state, a thread of the screw rod  32  is engaged with the first and second screw thread  50   a,    52   a  of the upper and lower U-shaped wall  50 ,  52 . The supporting mechanism  34  and the adjusting mechanism  36  are fixed to the screw rod  32  and will not accidentally slide. To adjust the height of the supporting mechanism  34 , users rotate the base  46  and the screw rod  32 .  
         [0021]    [0021]FIG. 6 shows the stand  30  in a rough adjustable state. As shown in FIG. 6, when the key portion  38  is depressed, the adjusting mechanism  36  is able to rotate along the axis  54 . The screw threads  50   a,    52   a  of the upper and lower U-shaped wall  50 ,  52  of the hole portion  48  do not make contact with the screw rod  32  so that the adjusting mechanism  36  can tilt at a predetermined angle over the screw rod  32 . When the adjusting mechanism  36  tilts, the upper and lower U-shaped walls  50 ,  52  will separate from the screw rod  32  allowing the adjusting mechanism  36  and the supporting mechanism  34  to slide along the screw rod  32 . In this state, users are able to rapidly and conveniently adjust the height of the supporting mechanism  34 .  
         [0022]    Please refer to FIG. 7 and FIG. 8. FIG. 7 and FIG. 8 are operational diagrams of another stand  60  according to the present invention. The stand  60  is also capable of fine adjustment and rough adjustment. FIG. 7 shows that the stand  60  is in a fine adjustable state. FIG. 8 shows that the stand  60  is in rough adjustable state. Users can do rough adjustment by depressing the key portion  68 . The operational principles are similar to the stand  30  mentioned above. The difference between this stand  60  and the stand  30  mentioned above is that the axis  84  and the upper U-shaped wall  80  of this stand  60  are on the same side of the hole portion  68  (the right side of the hole portion  68  shown in FIG. 7). In the state shown in FIG. 7, if users push down on the supporting mechanism  64  directly, the supporting mechanism  64  and the adjusting mechanism  66  will slide downward. As shown in FIG. 7, when users push down on the supporting mechanism  64  (as F 1  shown in FIG. 7), pressure will be exerted on the axle  86  of the adjusting mechanism  66  (as F 2  shown in FIG. 7) so that the adjusting mechanism  66  tilts at a certain angle over the screw rod  62 . This will cause the upper and lower U-shaped walls  80 ,  82  to separate from the screw rod  62 , and allow the adjusting mechanism  66  and the supporting mechanism  64  to slide downward along the screw rod  32 . When users stop pressing the supporting mechanism  64 , the spring  70  will make the upper and lower U-shaped walls  80 ,  82  contact the screw rod  62 . This will cause the supporting mechanism  64  and the adjusting mechanism  66  to remain fixed on the screw rod  62 . This design allows users to press down directly on the supporting mechanism  64  in order to quickly lower its height. Of course, the elastic force of the spring  70  must be sufficiently strong to prevent the supporting mechanism  64  from sliding down as a result of the weight of the predetermined device (such as a projector).  
         [0023]    The present invention is not only limited to the embodiments mentioned above. All similar designs that use the opposed position of the upper and lower U-shaped walls  50 ,  52 ,  80 ,  82  to make the adjusting mechanism  36 ,  66  tilt at a certain angle over the screw rod  32 ,  62  and slide along the screw rod  32 ,  62  conform to the essence of the present invention.  
         [0024]    In contrast to the prior art stand  10 , the upper and lower U-shaped walls  50 ,  52 ,  80 ,  82  of the present invention stand  30 ,  60  do not entirely cover the screw rod  32 ,  62  allowing the adjusting mechanism  36 ,  66  to tilt a certain angle over the screw rod  32 ,  62  and separate from the screw rod  32 ,  62 , so that the supporting mechanism  34 ,  64  is able to slide along the screw rod  32 ,  62 . In this manner, the stand  30 ,  60  according to the present invention allows for both fine and rough adjustment functions. Users can rapidly and conveniently adjust the supporting mechanism  34 ,  64  to the desired height.  
         [0025]    Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.