Abstract:
Support structure for a projector. The projector includes an optical engine, a lens sleeve and a support structure. The lens sleeve has an end connected to the optical engine, like a cantilever beam. The support structure supports the lens sleeve in such a manner that the lens sleeve can be rotated.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to a support structure for a projector. 
     2. Description of the Related Art 
     Referring to FIG. 1, a conventional lens sleeve  12  has an end fixed to an optical engine  10  via screws  11 , and other portions extending out from the optical engine  10  like a cantilever beam. In operation, the lens sleeve  12  is rotated to adjust the focus or zoom. 
     The lens sleeve  12  bends due to its own weight. The above support structure supports the lens sleeve  12  well when the lens sleeve  12  is small, however, a large lens sleeve bends significantly, so that the lenses therein tend to deviate from predetermined positions. Thus, adjusting the focus is difficult. More seriously, the lens sleeve  12  cannot be rotated to adjust the focus and zoom. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to improve the support structure for a projector. The improved support structure prevents the lens sleeve from bending, allowing the lens sleeve to be freely rotated. 
     The projector of the present invention includes an optical engine, a lens sleeve and a support structure. The lens sleeve has an end connected to the optical engine, like a cantilever beam. The support structure supports the lens sleeve via rollers or pads so that the lens sleeve can be rotated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
     FIG. 1 is a schematic diagram of a conventional support structure for a projector; 
     FIG. 2 depicts a support structure of a projector in accordance with a first embodiment of the present invention; 
     FIG. 3 is an exploded diagram of a lower support frame of the support structure of FIG. 2; 
     FIG. 4 is an exploded diagram of an upper support frame of the support structure of FIG. 2; 
     FIG. 5 is a sectional view of FIG. 2, along line V—V; 
     FIG. 6 depicts a support structure of a projector in accordance with a second embodiment of the present invention; and 
     FIG. 7 is a sectional view of FIG. 6, along line VII—VII. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 2 depicts a support structure of a projector in accordance with a first embodiment of the present invention, wherein a lens sleeve  22  is screwed to an optical engine  20 . To prevent the lens sleeve  22  from bending due to its own weight, the lens sleeve  22  is supported by a support structure  23 . 
     The support structure  23  of the present invention includes an upper lens support frame  231  and a lower lens support frame  232 , both of which have semicircular configurations so that the lens sleeve  22  can be held by the upper lens support frame  231  and the lower lens support frame  232 . Referring to FIG. 3, the lower lens support frame  232  has a body  2321  and a cover  2322 . Two recesses  2325  are provided on the body  2321 . The body  2321  and the cover  2322  are fixed together by screws  2329 , with two resilient pieces  2323  and rollers  2324  disposed in the recesses  2325  of the body  2321 , wherein the screws  2329  are twisted through the holes  2329 ′ of the cover  2322  into the holes  2329 ″ of the body  2321  to fix the body  2321  and the cover  2322  together. Furthermore, two slits  2327 ,  2327 ′ are provided on the body  2321  to communicate with the recess  2325 . A grooved hole  2326  is provided in the recess  2325  on the body  2321 , while a slot  2328  is provided on the cover  2322  corresponding to the grooved hole  2326  of the body  2321 . In assembly, the ends of the resilient piece  2323  are fitted into the slits  2327 ,  2327 ′ so that the resilient piece  2323  is fixed. The shaft of the roller  2324  is disposed in the grooved hole  2326  at one end and disposed in the slot  2328  at the other end, with the resilient piece  2323  pushing against the roller  2324  (a pre-load). 
     Referring to FIG. 4, the upper lens support frame  231  has a structure similar to the lower lens support frame  232 . The upper lens support frame  231  has a body  2311  and a cover  2312  fixed together via screws  2319 . The resilient pieces  2313  and the rollers  2314  are housed in the recesses  2315 , while the resilient pieces  2313  apply a pre-load on the rollers  2314 . The resilient pieces  2313  are made of, for example, metal. The upper lens support frame  231  is aligned with the lower lens support frame  232  by pins  2310  of the upper lens support frame  231  fitting into holes  2320  of the lower lens support frame  232 . Then, screws (not shown) are twisted through holes  2310 ′,  2320 ′ to fix the upper and lower lens support frames  231 ,  232  together. 
     Referring to FIG. 5, the upper and lower rollers  2314 ,  2324  are pushed by the resilient pieces  2313 ,  2323  to support the lens sleeve  22 . In operation, the upper and lower rollers  2314 ,  2324  rotated according to the rotation of the lens sleeve  22 . 
     FIG. 6 depicts a support structure of a projector in accordance with a second embodiment of the present invention, wherein a support structure  63  includes an upper lens support frame  631  and a lower lens support frame  632 , both of which have concave configuration so that a lens sleeve  62  can be held by the upper lens support frame  631  and the lower lens support frame  632 . 
     Referring to FIG. 7, the upper lens support frame  631  and the lower lens support frame  632  are integrally formed parts, with through holes therein to form a plurality of curved ribs  6311 ,  6321  to improve the elasticity thereof. Pads  6312 ,  6322  are respectively glued to the upper lens support frame  631  and the lower lens support frame  632  to contact the lens sleeve  62 . The pads  6312 ,  6322  are made of material with low friction coefficient. In operation, the rotating lens sleeve  62  directly rubs the pads  6312 ,  6322  without impediment. 
     In conclusion, the present invention provides an improved support structure to prevent the lens sleeve from bending, without locking the rotation of the lens sleeve. The conventional problem is effectively solved. 
     While the invention has been described by way of example and in terms of the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.