Abstract:
The present invention is related to a height adjustment device adapted in the projection apparatus and projection apparatus comprising the height adjustment device. The projection apparatus has a body and a height adjustment device. The height adjustment device comprises at least one connecting element, a rotary plate, and a screw. The connecting element is connected to the body. The rotary plate meshes with the connecting device for relative rotation, and a threaded hole is formed at the center of the rotary plate. The screw is inserted through the threaded hole to enable the rotary plate to make a linear up-down movement along the axis of the screw when the rotary plate rotates around the screw. Thus, the height adjustment device of the present invention enables a height adjustment without requiring strenuous effort and damaging the projection apparatus.

Description:
This application claims priority to Taiwan Patent Application No. 096212786 filed on Aug. 3, 2007, the disclosures of which are incorporated herein by reference in their entirety. 
     CROSS-REFERENCES TO RELATED APPLICATIONS 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention provides a height adjustment device adapted for a projection apparatus; and more particularly, it provides a height adjustment device for adjusting a slanting angle of a projected image in a projection apparatus by changing the height of the side of the projection apparatus. 
     2. Descriptions of the Related Art 
     With the rapid development of information propagating technologies, projection apparatuses have been used both in home A/V entertainment activities and in meeting presentations of business entities. Meanwhile, the evolvement of associated technologies has made projection apparatuses increasingly lightweight and miniaturized, which further contributes to the increasing popularity of these products. 
     In practice, a projection apparatus frequently needs to be adjusted in terms of the projection angle thereof according to the concrete surroundings of the user. For example, when a projection apparatus is used within a relatively restricted space or installed at a particular location, it would be difficult to position the projection apparatus as far back as possible to zoom in or to improve the quality of an image. In this case, the user may accomplish this goal by elevating the projection side of the projection apparatus to a certain elevation angle. Similarly, when a support or a platform on which the projection apparatus is installed is not leveled, the lateral tilting angle of the projection apparatus has to be adjusted in such a way that distortion will not occur in the projected image, thus ensuring the quality of the image projected. 
       FIG. 1  is a perspective view of a projection apparatus  1  of the prior art. The projection apparatus  1  has a height adjustment device  11  and a body  13  which further has a housing  10 . The height adjustment device  11  is disposed below the front side of the body  13  and extends partially beyond the housing  10 . For further illustration, a perspective view of the height adjustment device  11  is depicted in  FIG. 2 . The height adjustment device  11  has a clamp spring body  110 , a clamp spring controlling element  111  and a screw  112 . The clamp spring body  110  is formed with a hole  110   a  for the screw  112  to insert therethrough. The clamp spring controlling element  111  is connected with the clamp spring body  110  and engaged with a clamp spring (not shown) inside the clamp spring body  110  to fix the screw  112  within the hole  110   a  indirectly. Accordingly, the height adjustment device  11  adjusts the height in the following way: the clamp spring for clamping the screw  112  in the clamp spring body  110  is released by pressing the clamp spring controlling element  111 , and then the projection apparatus  1  is lifted to manually adjust the extended length of the screw  112  to adjust the projection apparatus  1  to an appropriate height. Once the desired height is obtained, the clamp spring controlling element  111  is released and the clamp spring clamps and consequently fixes the screw  112  again. 
     However, in case the projection apparatus has a large weight, strenuous effort is needed to lift it up. Moreover, when the projection apparatus is lowered down, the potential shock or impact may be caused if the projection apparatus is not handled carefully or the clamp spring is not clamped to the screw securely, thus causing damage to the projection apparatus. 
     On the other hand, such height adjustment devices  11  are mostly adapted to change the height of the projected image by adjusting an elevation angle and the depression angle of the projection apparatus. However, the installation of a projection apparatus affects not just the height of an image projected. For example, when the projection apparatus is installed on an unleveled floor or a support, an image projected will be out of level, causing the slanting of the image in the left-right direction. Since the requirements on the slanting adjustment amount are lower than those on the height adjustment, only a fine tuning is required on the slanting angle. In this case, the height adjustment device  11  which delivers a substantial adjustment will not apply. For this reason, none of the projection apparatuses currently available are provided with an adjustment device for adjusting the slanting angle of an image. 
     In view of this, it is highly desirable in the art to provide a novel height adjustment device mainly adapted for the fine adjustment of the slanting angle in the left-right direction without requiring strenuous effort and causing potential damage to the projection apparatus. 
     SUMMARY OF THE INVENTION 
     One objective of this invention is to provide a height adjustment device adapted for a projection apparatus, which adjusts the height of at least one side of the projection apparatus in the left-right direction by using a simple height adjustment means. As a result, the height adjustment device can indirectly change the laterally slanting angle of the projection apparatus without requiring strenuous effort and causing potential shock or impact in lifting the apparatus. 
     This invention discloses a height adjustment device adapted for a projection apparatus. The projection apparatus has a body. The height adjustment device comprises at least one connecting element, a rotary plate, a screw and a stopper. The at least one connecting element is connected to the body. The rotary plate is engaged with the at least one connecting element for the relative rotation with respect to each other, while the rotary plate is provided with a threaded hole at a center thereof. The screw is screwed through the threaded hole to enable the rotary plate to move axially relative to the screw when the rotary plate rotates around the screw. 
     This invention further discloses a projection apparatus incorporating the aforesaid height adjustment device. The projection apparatus comprises a body and a height adjustment device as defined above. The body has a case. The height adjustment device comprises at least one connecting element, a rotary plate, a screw and a stopper. The at least one connecting element is connected to the body. The rotary plate is engaged with the at least one connecting element for relative rotation with respect to each other. The rotary plate is provided with the threaded hole at the center thereof, through which the screw is screwed. When the rotary plate is rotated around the screw to move linearly, it is adapted to drive the body to make a linear movement synchronously relative to the screw. 
     The detailed technology and preferred embodiments implemented for the subject invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a projection apparatus of the prior art; 
         FIG. 2  is a perspective view of a height adjustment device of  FIG. 1 ; 
         FIG. 3A  and  FIG. 3B  are perspective views of this invention at two different perspective angles; 
         FIG. 3C  is an enlarged view of a circled portion in  FIG. 3B ; 
         FIG. 4A  is a perspective view of the height adjustment device in accordance with the first embodiment of this invention; 
         FIG. 4B  is a cross-sectional view of the height adjustment device of  FIG. 4A  taken along line A-A′; 
         FIG. 5A  is a perspective view of a height adjustment device in accordance with the second embodiment of this invention; and 
         FIG. 5B  is a cross-sectional view of the height adjustment device of  FIG. 5A  taken along line B-B′. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The first embodiment of this invention is a projection apparatus  3 , a perspective view of which is shown in  FIG. 3A . The projection apparatus  3  has a body  34  and a height adjustment device  31 . The body  34  has a case  30 . The height adjustment device  31  is disposed on the rear left side of the body  34  with respect to an image projecting end. In other embodiments, the height adjustment device  31  may also be disposed at any location on the left and/or right side of the projection apparatus  3 .  FIG. 4A  depicts a perspective view of the height adjustment device  31 , which comprises a connecting element  40 , a rotary plate  41 , a screw  43 , a stopper  44  and a buffer cushion  45 . 
     The connecting element  40  is connected to and formed integrally with the body  34 . As shown in  FIG. 4B , a cross-sectional view of the height adjustment device  31  of  FIG. 4A  taken along line A-A′ is depicted therein. The rotary plate  41  has a protrusion portion  410 , an annular body  411  and an annular neck portion  412 . The protrusion portion  410  is formed under the annular body  411  and cooperates with the annular body  411  to define the annular neck portion  412 . On the other hand, the connecting element  40  has a recess portion  400  and an annular shoulder portion  401  which defines the recess portion  400 . The recess portion  400  has a shape corresponding to that of the protrusion portion  410 . When the rotary plate  41  and the connecting element  40  are movably engaged to accomplish a rotation relative to each other, the protrusion portion  410  of the rotary plate  41  is engaged in the recess portion  400  of the connecting element  40  and the annular shoulder portion  401  is engaged in the annular neck portion  412  to render the connecting element  40  and the rotary plate  41  inseparable along the axis. In this way, the connecting element  40  and the rotary plate  41  are engaged with and rotated relative to each other. 
     Disposed at the center of the rotary plate  41  is a threaded hole  42 , into which the screw  43  is screwed. When rotated around the screw  43 , the rotary plate  41  moves linearly along the axis of the screw  43 . Because the rotary plate  41  is engaged with the connecting element  40 , the axial movement of the rotary plate  41  along the screw  43  will force the connecting element  40  to move together. As previously described, the connecting element  40  is connected with the body  34  of the projection apparatus  3 , so with the linear movement caused by rotating the rotary plate  41 , the body  34  is elevated by a certain height. Consequently, the horizontal angle, and thereby the slanting angle in the left-right direction, of the image projected by the projection apparatus  3  can be adjusted. 
     To prevent the rotary plate  41  from rotating out of the screw  43  when moving toward the upper side of the screw  43 , the stopper  44  is disposed in the upper region of the screw  43  in this embodiment to stop the rotary plate  41 . In this embodiment, the stopper  44  is a C-shaped clamp spring. However, other kinds of stoppers readily occurring to those skilled in the art may be used in other embodiments. Additionally, the buffer cushion  45 , which is made of an elastic material (e.g., a rubber material), is disposed at the bottom of the screw  43 . This may increase the friction force against the torque of the rotating rotary plate  41  and provide enhanced buffering and support when the projection apparatus  3  is handled to provide better protection and support for the projection apparatus  3  as a whole. 
       FIG. 3B  is a perspective view of the projection apparatus  3  at a different perspective angle. The case  30  of the projection apparatus  3  has a hole  32  and an opening  33 , an enlarged view of which is shown in  FIG. 3C . The hole  32  is disposed at the bottom of the case  30  for the screw  43  to insert therethrough. The lower end of the screw  43  protrudes out of the case  30  and comes into contact with the floor or the support with the buffer cushion  45  thereof. The lower end of the screw  43  has a non-circular cross-section  43   a , while the hole  32  has a shape complementary with the non-circular cross-section  43   a . As shown in  FIG. 3C , in this embodiment, the non-circular cross-section  43   a  is formed by cutting an original circular cross-section along the chord other than the diameter. By inserting the screw  43  with a non-circular cross-section  43   a  into the complementary non-circular hole  32 , the screw  43  is restricted from rotating in company with the rotary plate  41 . Furthermore, the opening  33  is formed on the sidewall of the case  30 , and is adapted to expose a portion of the rotary plate  41  out of the case  30  to facilitate adjustment by the user. Positions of the hole  32 , the case  30 , the opening  33  and the rotary plate  41  relative to each other are illustrated more clearly in  FIG. 4B . 
     The second embodiment of this invention is also a projection apparatus with a height adjustment device. Unlike previous embodiments, the connecting element and the rotary plate in the height adjustment device of this embodiment are engaged with each other in a different configuration. Hence, only the height adjustment device will be particularly described herein.  FIG. 5A  is a perspective view of the height adjustment device  31 ′ in accordance with the second embodiment of this invention, while  FIG. 5B  is a cross-sectional view of the height adjustment device  31 ′ of  FIG. 5A  taken along line B-B′. As shown in both  FIGS. 5A and 5B , the height adjustment device  31 ′ comprises a pair of connecting elements connected with each other, a rotary plate  52 , a screw  54 , a stopper  55  and a buffer cushion  56 . 
     The pair of connecting elements connected with each other are a first connecting element  50  and a second connecting element  51  disposed above and below the rotary plate  52  respectively. Both the first connecting element  50  and the second connecting element  51  are connected to and formed integrally with the body (not shown) of the projection apparatus. As can be seen from  FIG. 5B , the rotary plate  52  are movably engaged with the first connecting element  50  and the second connecting element  51  in a relative rotation manner. The rotary plate  52  is formed with a threaded hole  53  at the center thereof, into which the screw  54  is screwed. When being rotated around the screw  54 , the rotary plate  52  is adapted to move linearly along the axis of the screw  54 . As in the previous embodiment, the rotary plate  52  is partially exposed out of the case  30 ′ through an opening  33 ′, while the screw  54  is inserted through a non-circular hole  32 ′. 
     To prevent the rotary plate  52  from rotating out of the screw  54 , a stopper  55  is also disposed in the upper region of the screw  54  in this embodiment to stop the rotary plate  52 . In this embodiment, the stopper  55  is a C-shaped clamp spring. However, other kinds of stoppers readily occurring to those skilled in the art may be used in other embodiments. Additionally, a buffer cushion  56 , which is made of an elastic material (e.g., a rubber material), is disposed at the bottom of the screw  54 . This may increase the friction force against the torque of rotating the rotary plate  52  and provide enhanced buffering and support when the projection apparatus is handled to provide better protection and support for the projection apparatus as a whole. 
     It should be emphasized that the manner in which the rotary plate and the connecting element are engaged with each other is not merely limited to what described above, and other embodiments in this aspect may readily occur to those skilled in the art. Similarly, in other embodiments, the number and locations of the height adjustment devices are not merely limited to what is described above, while the height adjustment device may also be used to replace devices for adjusting an elevation angle and a depression angle in solutions of the prior art. 
     It follows from the above description that with the height adjustment device of this invention, the height of a screw is adjusted by rotating a rotary plate, and then through the engagement between the rotary plate and the connecting element, the elevated height at the side of the projection apparatus is changed. As a result, no strenuous effort is needed to lift the project apparatus or to prevent potential shock or impact to the projection apparatus. In addition, the slanting angle of the projected images in the horizontal direction can be fine tuned. 
     The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.