BACKGROUND OF THE INVENTION 
       [0001]    a) Field of the Invention 
         [0002]    The present invention relates to a multi-purpose adjustable quick expandable installment, and more particularly to an adjustable expandable installment which can be formed integrally, and can save production cost and manual operation fees, thereby constituting a multi-purpose quick and free ascending and descending or expandable installment. 
         [0003]    b) Description of the Prior Art 
         [0004]    Ordinarily, expansion between two expandable objects, such as between two slabs, between two cylindrical objects, within an expandable foot stand, within an expandable table leg or within a foldable bicycle, is carried out by external screws, springs, snaps, collars or additional outer sleeves, so as to change height or length between the two objects or to fix the two objects to prevent from sliding. 
         [0005]    In addition, an existing manhole cover used on a pavement is covered on a through-hole. As it is unable to adjust height of the manhole cover, when the pavement is re-patched, due to that the pavement should be re-paved with asphalt, the patched pavement will have a difference in height as compared to the original pavement that the patched pavement may be higher or lower than the original pavement. 
         [0006]    At this time, as it is unable to adjust the height of the ordinary manhole cover, it will also result in the difference in height between the manhole cover and the re-paved pavement after patching the pavement, causing the pavement to be rough that the pavement may be raised or be provided with pots. This will easily endanger road users; especially that it is a rather severe safety risk to the road users who ride on motorcycles or bicycles. 
         [0007]    Accordingly, in order to improve the aforementioned issues, there are manhole covers with adjustable height on market. However, as the conventional manhole structures are very complicated, they are inconvenient in production and are not easily operated. Moreover, their functions are limited in that they cannot perform quick fine-adjustment to the height, and they are also more expensive in cost. 
       SUMMARY OF THE INVENTION 
       [0008]    The primary object of the present invention is to provide a multi-purpose adjustable expandable installment which is able to save production cost and manual operation fees, and perform quick fine-adjustment to the height. 
         [0009]    To achieve the aforementioned object, the multi-purpose adjustable quick expandable installment of the present invention includes an outer frame and an inner frame, both of which can be formed integrally. A snap design for ascending and descending adjustment is implemented primarily with slopes between the outer frame and the inner frame, such that the inner frame can quickly ascend and descend in fine-adjustment in the outer frame, thereby achieving an effect that the height of the inner frame can be finely adjusted in the outer frame. 
         [0010]    Besides, the present invention can be also combined with the existing manhole cover for use, such that by changing minimally the existing manhole cover, the manhole cover can be assembled with the multi-purpose adjustable quick expandable installment of the present invention. Therefore, cost for replacing the manhole cover can be reduced significantly, and the multi-purpose adjustable quick expandable installment which is provided with economical benefits can be further provided. 
         [0011]    To enable a further understanding of the said objectives and the technological methods of the invention herein, the brief description of the drawings below is followed by the detailed description of the preferred embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  shows a three-dimensional exploded view of the present invention. 
           [0013]      FIG. 2  shows a schematic view of an unfolded outer frame of the present invention. 
           [0014]      FIG. 3  shows a schematic view of an unfolded inner frame of the present invention. 
           [0015]      FIG. 4  and  FIG. 5  show schematic views of an outer frame and an inner frame of the present invention, which are unfolded and overlapped, disclosing a condition that a relative height between the outer frame and the inner frame is adjusted. 
           [0016]      FIG. 6  shows a schematic view of a second embodiment of the present invention, wherein an outer frame and an inner frame are unfolded and overlapped. 
           [0017]      FIG. 7  shows a three-dimensional exploded view of the present invention applying to a circular manhole cover. 
           [0018]      FIG. 8  and  FIG. 9  show cutaway views of the present invention which is applied to a circular manhole cover, disclosing conditions of adjustment. 
           [0019]      FIGS. 10A to 10C  show cutaway views of a saw-tooth design and an ascending or descending operation, of first retainers and second retainers, according to the present invention. 
           [0020]      FIGS. 11A to 11C  show cutaway view of a saw-tooth design of first retainers and second retainers which are arranged oppositely and ascending or descending, according to the present invention. 
           [0021]      FIG. 12  shows a three-dimensional exploded view of the present invention applying to a rectangular manhole cover. 
           [0022]      FIGS. 13 to 15  show cutaway views of the present invention which is applied to a rectangular manhole cover, disclosing conditions of adjustment. 
           [0023]      FIG. 16  shows a schematic view of the present invention which is applied in adjusting a circular manhole cover. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    Referring to  FIG. 1 , in association with  FIG. 2  and  FIG. 3 , it shows a schematic view of a first embodiment of a multi-purpose adjustable expandable installment of the present invention. The adjustable expandable installment comprises an outer frame  10  and an inner frame  20 . 
         [0025]    The outer frame  10  can be an integrally formed hollow tube and an inner wall  11  of the hollow tube is provided with plural first type retainers  12  which are protruded from the inner wall  11 . In association with  FIG. 2  which is an unfolded view of the outer frame  10 , the first type retainers  12  are arranged obliquely from low to high on the inner wall  11 ; whereas on the physical outer frame  10 , the first type retainers  12  are arranged helically. 
         [0026]    The inner frame  20  also can be formed integrally and can be emplaced in an interior of the outer frame  10 . Aside wall  21  of the inner frame  20  is provided with plural second type retainers  22 . In association with  FIG. 3  which is an unfolded view of the inner frame  20 , the second type retainers  22  are also arranged obliquely from low to high on the side wall  21 ; whereas, on the physical inner frame  20 , the second type retainers  22  are arranged helically and correspond to and can be latched with the first type retainers  12 . 
         [0027]    In association with  FIG. 4 , when the inner frame  20  is emplaced inside the outer frame  10 , a relative position and a relative height of the inner frame  20  with respect to the outer frame  10  can be fixed by latching the first type retainers  12  with the second type retainers  22 . In addition, in association with  FIG. 5 , when the inner frame  20  is displaced angularly with respect to the outer frame  10 , the first type retainers  12  can be latched with the second type retainers  22  at different levels, such that a finely adjusted ascending or descending movement can be formed to the inner frame  20  with respect to the outer frame  10 ; that is, when the inner frame  20  rotates with respect to the outer frame  10 , the inner frame  20  can ascend or descend accordingly. 
         [0028]    The first type retainers  12  and the second type retainers  22  can be in a rectangular shape, a tooth shape or an arc shape. As long as that the first type retainers  12  can be latched with the second type retainers  22 , any geometrical shape can apply. 
         [0029]    On the other hand, as shown in  FIG. 6 , it shows a schematic view of a second embodiment of the present invention. The first type retainers  12  manifest primarily a saw-tooth design and the second type retainers  22  also manifest a saw-tooth design corresponding to the first type retainers, whereas, the third type retainers  32  and the fourth type retainers  33  manifest an oppositely arranged saw-tooth design, wherein a proper gap can be provided between the neighboring first type retainers  12  and between neighboring third type retainers  32 ; whereas, a proper gap can be also provided between the neighboring second type retainers  22  and between the neighboring fourth type retainers  33 . The gap between the neighboring first type retainers  12  and between the neighboring third type retainers  32  is larger than the size of the second type retainers  22  and the size of the fourth type retainers  33  and the gap between the neighboring second type retainers  22  and between the neighboring fourth type retainers  33  is larger than the size of the first type retainer  12  and the size of the third type retainers  32 . This design allows that when the outer frame  10  is assembled with the inner frame  20 , each first type retainer  12  and each third type retainer  32  can pass through directly the gap between the neighboring second type retainers  22  and between the neighboring fourth type retainers  33  and each second type retainer  22  and each fourth type retainers  33  can also pass through directly the gap between the neighboring first type retainers  12  and the gap between the neighboring third type retainers  32 ; whereas, the gap between any two retainers is also larger than the size of that retainer. Accordingly, the outer frame  10  and the inner frame  20  can be quickly assembled to a desired relative height, and then, rotate relatively so that the first type retainers  12  can be latched with the second type retainers  22 , thereby accomplishing assembling or adjusting. Furthermore, if the first type retainers  12  and the second type retainers  22  are formed with right-angled triangles, then third type retainers  32  and fourth type retainers  33  are formed with right-angled triangles on opposite oblique surfaces, so as to result in a reaction force to inhibit movement between the outer frame  10  and the inner frame  20 , thereby generating a stable force by which the outer frame  10  and the inner frame  20  can be fixed without any accessories. 
         [0030]    Referring to  FIG. 7 , it shows a schematic view of a third embodiment of the present invention. When the present invention is applied to an existing circular manhole cover, an inner wall of the inner frame  20  is provided with plural second type retainers  22  which constitute a slope and the top end of the slope does not exceed a proper height of the inner frame  20 , with the side wall  21  being attached with a pad to stop water and mud from coming in. 
         [0031]    On the other hand, the inner wall  11  of the outer frame  10  is provided with plural individual first type retainers  12 , which are fixed on the inner wall  11 , the height of the top end does not exceed a proper height of the inner frame  20  and which correspond to the second retainers  22 . 
         [0032]    When the height needs to be adjusted, it only needs to lift up the inner frame  20  and rotate toward left or right a little that the inner frame  20  can ascend or descend with respect to the outer frame  10  by a change of positions of the first and second type retainers. At this time, as the heights of the two type retainers are only a half or less than a half of a height of the manhole cover, an upper part can keep sealed; that is, water and mud can be prevented from coming in. In addition, a side wall and a lower seat of the outer frame  10  are provided additionally with a pad  13  to block noise and to seal. Referring to  FIG. 16  at the same time, by increasing a height of one or plural first type retainers  12 , a manhole cover  30  can be tilted to fit with the slope of the ground surface, such that a special tiltable manhole cover can be replaced without wasting a huge manpower and cost, thereby achieving an object of reducing CO 2  emission to protect environment. 
         [0033]    Referring to  FIG. 8 , when practically applying the present invention that is implemented to the manhole cover  30 , a top surface of the manhole cover  30  should be at the same level as the pavement  40 ; in the mean time, a tolerance of difference in height should not exceed a certain range. Once the pavement  40  is patched and re-paved (as shown in  FIG. 9 ), a difference in height between the new pavement  40 ′ and the manhole cover  30  will usually be larger than the allowable tolerance. At this time, it only needs to lift up the inner frame  20 , allowing the top surface of the cover  30  to be at same height as the new pavement  40 ′. In addition, by latching the first type retainers  12  with the second type retainers  22  for positioning, the cover  30  can be fixed at the same height as the new pavement  40 ′. 
         [0034]    Accordingly, through a simple rotation, a quick ascending or descending fine-adjustment operation can be achieved. Furthermore, the existing manhole cover can be combined with the present invention for use, so as to achieve a manhole cover structure which can be finely and quickly adjusted, without replacing a new manhole cover. 
         [0035]    Referring to  FIGS. 10A to 10C , it shows the cutaway views of the fourth embodiment of the present invention, wherein the inner frame  20  is ascending or descending within the outer frame  10 . As shown in the drawings, the first type retainers  12  and the second type retainers  22  are manifested as another implementation configuration. The first type retainers  12  manifest primarily a saw-tooth design and the second type retainers  22  also manifest a saw-tooth design corresponding to the first type retainers; whereas, the third type retainers  32  and the fourth type retainers  33  manifest an oppositely arranged saw-tooth design. As a result, a reaction force is generated at the first and second type retainers to prevent from sliding and to form a finely adjusted ascending or descending operation to the inner frame  20  of a manhole seat; that is, a single-rail snap is formed by latching the first type retainers  12  with the second type retainers  22 , thereby achieving a positioning effect. In particular, all of the first type retainers  12  and the second type retainers  22  manifest a slope configuration, allowing the inner frame  20  of the manhole seat to ascend or descend in fine adjustment within the outer frame  10  of the manhole seat by rotation. 
         [0036]    As the height of the second type retainer  22  does not exceed a proper height of the whole wall, an upper part will form a sealed state between a shield wall  26  and the outer frame  10  to prevent water and mud from coming in. 
         [0037]    Referring to  FIG. 10A , when the first type retainers  12  are completely latched with the second type retainers  22 , the manhole cover  30  is at the same level with the outer frame  10  and the inner frame  20  of the manhole seat. 
         [0038]    When the height of the manhole cover  30  is to be adjusted, it only needs to rotate the inner frame  20 , allowing the first type retainers  12  to be latched with the second type retainers  22  by a three-quarter of area, as shown in  FIG. 10B , so as to achieve a finely adjusted ascending or descending operation. On the other hand, as the inner frame  20  and the outer frame  10  are assembled together by latching the first type retainers  12  with the second type retainers  22 , when adjusting the height, it only needs to rotate the inner frame  20  directly so that the fine adjustment operation can be achieved. 
         [0039]    Besides, if the height of the cover  30  is adjusted to a higher position, then it only needs to rotate the inner frame  20  further, allowing the first type retainers  12  to be latched with the second type retainers  22  by a half of area, as shown in  FIG. 10C , so as to increase a height difference between the cover  30  and the outer frame  10 . 
         [0040]    As a result, through a simple rotation operation, a quick ascending or descending fine adjustment operation can be achieved. Furthermore, the existing manhole cover can be combined with the present invention for use, so as to achieve a manhole cover structure which can be finely and quickly adjusted. 
         [0041]    Referring to  FIGS. 11A to 11C , it shows schematic views of an ascending or descending operation of the fifth embodiment of the present invention. As shown in the drawings, the saw-tooth design of the first type retainers  12  in the outer frame  10  can be arranged oppositely, whereas the second type retainers  22  on the inner frame  20  correspond to the first type retainers  12 , such that through the opposite arrangement of the first type retainers  12  and the second type retainers  22  relative to the third type retainers  32  and the fourth type retainers  33 , the inner frame  20  can be more stably latched with the outer frame  10 , thereby preventing from slipping off. 
         [0042]    On the other hand, referring to  FIG. 12 , it shows a schematic view of the sixth embodiment of the present invention. When the present invention is applied to a rectangular manhole cover, the outer frame  10  and the inner frame  20  are in a rectangular shape and the first type retainers  12  on the outer frame  10  are made to slide with respect to the outer frame  10 , primarily through providing plural sliding slots  14  on the outer frame  10 . Therefore, the first type retainers  12  can move transversally toward left or right on the outer frame  10  through the sliding slots  14 , so that by collaborating with the second type retainers  22  on the inner frame  20 , the inner frame  20  can be expandable by ascending or descending on the outer frame  10 . 
         [0043]    In addition, the maximum height of the first type and second type retainers does not exceed a proper size of a full height of the wall, and reserved portions will constitute the shield wall  26 , keeping a space between the outer frame  10  and the inner frame  20  at a sealed state; that is, water and mud can be prevented from coming in. Moreover, the side wall  11  or  21  and the bottom seat are additionally provided with the pad  13  to block noise and to seal. 
         [0044]    Referring to  FIG. 13  and  FIG. 14 , when the present invention is applied to a rectangular manhole cover, it only needs to move the first type retainers  12  that a relative height of the inner frame  10  can be adjusted. It is worthy of mentioning that four edges of the rectangular outer frame  10  are all provided with the movable first type retainers  12 . When the first type retainers  12  at the front and rear edges are assembled respectively with the second type retainers  22  of different heights, the inner frame  20  will be tilted forward or backward. Whereas, when the first type retainers  12  at the left and right edges are assembled respectively with the second type retainers  22  of different heights, the inner frame  20  will be tilted leftward or rightward. This feature can be adjusted properly for a rough pavement (as shown in  FIG. 15 ). 
         [0045]    Finally, referring to  FIG. 16 , it shows a schematic view of the present invention which is applied to a circular manhole cover, allowing the manhole cover to be tilted. 
         [0046]    As shown in the drawing, when the present invention is applied to the circular manhole cover, an upper end of one or plural first type retainers  12  of the outer frame  10  is provided with a height extender  15  by which the inner frame  20  is tilted by an angle (as shown in the dotted line) within the outer frame  10  when the inner frame  20  is assembled with the outer frame  10  through the first type retainers  12  and the second type retainers  22 . 
         [0047]    However, as the manhole cover  30  is provided on the inner frame  20 , the manhole cover  30  is also titled by an angle along with the inner frame  20  and this feature can allow the circular manhole cover to be adjusted properly for a rough pavement. 
         [0048]    It is of course to be understood that the embodiments described herein is merely illustrative of the principles of the invention and that a wide variety of modifications thereto may be effected by persons skilled in the art without departing from the spirit and scope of the invention as set forth in the following claims.
The present invention discloses a multi-purpose adjustable quick expandable installment which can be quickly and finely adjusted and ascend or descend freely, by a snap design which adjusts ascending or descending with a slope principle, based on a mechanical principle that a force is constant if acting on a same area and an opposite force compensates with the force. Through a structure which follows the law of action and reaction to compensate with a sliding force which occurs naturally, a stable movement without moving accidentally is formed, so as to increase safety in adjustment of ascending and descending. Therefore, an adjustable expandable installment which is provided with multi-purposes and is able to quickly and freely ascend, descend or expand is provided.