Patent Document

BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to fitness machine technology, and more particularly to an incline angle adjustable stair climbing machine. 
     2. Description of the Related Art 
     Because modern people are busy with work and do not have much time to engage in outdoor sports and outdoor sport activities are susceptible to weather, in order not to be constrained by time and weather, office workers who love to exercise usually will prepare a fitness machine at home for use any time when desired to achieve the effect of fitness. In order to meet the needs of different users, various fitness machines with different functions are commercially available for selection, such as treadmills, steppers, elliptical machines, or stair climbing machines. In a stair climbing machine, the circulation of tread boards enables the user to simulate a stair climbing exercise, strengthening the muscle strength and improving the functions of the heart and the lungs. However, the climb gradient of regular stair climbing machines it normally fixed, not adjustable according to user training needs. Therefore, the fitness effect the user can get from a conventional stair climbing machine is very limited. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a stair climbing machine, which allows adjustment of the incline angle to change the climb gradient, satisfying different training needs. 
     To achieve this and other objects of the present invention, an incline angle adjustable stair climbing machine comprises a base frame, a tilting seat, a tilting seat adjuster, a staircase, and a tread board adjuster. The tilting seat has a rear end thereof pivotally connected to a rear end of the base frame. The tilting seat adjuster is mounted between an opposing front end of the base frame and an opposing front end of the tilting seat, and adapted for adjusting the incline angle of the tilting seat. The staircase is mounted at the tilting seat, comprising a plurality of tread boards biasable relative to the tilting seat. The tread board adjuster is mounted at the tilting seat and connected with the tread boards of the staircase, and adapted for adjusting the angle of each tread board relative to the tilting seat, maintaining each tread board constantly in horizontal. Thus, when using the incline angle adjustable stair climbing machine, operate the tilting seat adjuster to adjust the incline angle of the tilting seat and then operate the tread board adjuster to adjust the angle of each tread board, enabling the user to conduct stair-climbing exercises at different climb gradients accurately and comfortably. 
     Preferably, the incline angle adjustable stair climbing machine further comprises a handrail and a handrail adjuster. The handrail has a rear end thereof pivotally connected to the rear end of the base frame. The handrail adjuster is mounted between the front end of the tilting seat and an opposing front end of the handrail, and adapted to adjust the incline angle of the handrail, enabling the handrail to be synchronously adjusted with the tilting seat. 
     Preferably, the staircase further comprises a tread board adjustment frame. The tread board adjustment frame is vertically movably mounted at the tilting seat and connected with each tread board. The tread board adjuster is mounted between the tilting seat and the tread board adjustment frame for enabling the tread board adjuster to adjust the angle of each tread board via the tread board adjustment frame. 
     Other and further benefits, advantages and features of the present invention will be understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference characters denote like elements of structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an oblique top elevational view of an incline angle adjustable stair climbing machine in accordance with the present invention. 
         FIG. 2  corresponds to  FIG. 1  when viewed from another angle. 
         FIG. 3  is a side view of the incline angle adjustable stair climbing machine in accordance with the present invention. 
         FIG. 4  is an elevational view of a part of the present invention, illustrating the structure of the tread board adjuster. 
         FIG. 5  is a partial elevational view of the present invention, illustrating an operating status of the tread board adjuster. 
         FIG. 6  is an enlarged view of a part of the linkage of the incline angle adjustable stair climbing machine in accordance with the present invention. 
         FIG. 7  is a partial sectional view of the present invention, illustrating the structural relationship between the tread board, the tread board adjustment frame and the bracket. 
         FIG. 8  is similar to  FIG. 6 , illustrating the linkages operated and the tread boards lifted. 
         FIG. 9  is similar to  FIG. 3 , illustrating the incline angle of the stair climbing machine adjusted. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1, 2 and 4 , a stair climbing machine  10  in accordance with the present invention is shown. The stair climbing machine  10  comprises a base frame  20 , a tilting seat  30 , a tilting seat adjuster  40 , a handrail  50 , a handrail adjuster  60 , a staircase  70 , and a tread board adjuster  80 . 
     The base frame  20  is adapted to be positioned on a floor to provide a supporting effect. 
     The tilting seat  30  has a rear end thereof pivotally connected to a rear end of the base frame  20 . 
     The tilting seat adjuster  40  comprises a first motor  41 , a first screw rod  42 , and a first sleeve  43 . The first motor  41  is pivotally mounted at an opposing front end of the tilting seat  30 . The first screw rod  42  has a top end thereof connected to the first motor  41 . The first sleeve  43  is threaded onto the first screw rod  42  with a bottom end thereof affixed to the base frame  20 . Thus, when the first motor  41  is started to rotate the first screw rod  42  clockwise or counter-clockwise, the first screw rod  42  causes the first motor  41  to move axially upward or downward along the first screw rod  42 , thereby turning the tilting seat  30  upward or downward relative to the base frame  20 . 
     The handrail  50  has a rear end thereof pivotally connected to an opposing rear end of the base frame  20  for holding by user&#39;s both hands. 
     The handrail adjuster  60  comprises a second motor  61 , a second screw rod  62 , and a second sleeve  63 . The second motor  61  is pivotally connected to an opposing front end of the handrail  50 . The second screw rod  62  has a top end thereof connected to the second motor  61 . The second sleeve  63  is threaded onto the second screw rod  62  with a bottom end thereof pivotally connected to the front end of the tilting seat  30 . Thus, as shown in  FIG. 3  and  FIG. 9 , when the second motor  61  is started to rotate the second screw rod  62  clockwise or counter-clockwise, the second screw rod  61  causes the second motor  61  to move axially upward or downward along the second screw rod  62 , thereby turning the handrail  50  upward or downward relative to the tilting seat  30 . 
     The staircase  70  comprises two opposing front chain wheels  72 , two opposing rear chain wheels  73 , two chains  74 , and a plurality of tread boards  75  that are arranged in a front-rear parallel manner. The two front chain wheels  72  are mounted at the front end of the tilting seat  30  in opposing left and right positions with a front wheel axle  722 . The two rear chain wheels  73  are mounted at the rear end of the tilting seat  30  in opposing left and right positions with a rear wheel axle  732 . Each chain  74  is mounted around one respective front chain wheel  72  and one respective rear chain wheel  73  at one same side, enabling the respective chain wheels  72 , 73  to be rotated synchronously. Each tread board  75  is pivotally connected between the two chains  74  with a respective tread board axle  752  so that each tread board  75  can be carried by the chains  74  to cycle, and can also be biased up and down relative to the tilting seat  30 . The staircase  70  further comprises a tread board adjustment frame  76  (see  FIG. 7 ). The tread board adjustment frame  76  comprises two opposing side plates  77 , and two support rods  78  connected between the two side plates  77 . Each side plate  77  has an elongated slot  772  (see  FIG. 2 ) located near a front end thereof for the passing of the front wheel axle  722 , and a rectangular hole  774  (see  FIG. 1 ) located near an opposing rear end thereof for the passing of the rear wheel axle  732 . The elongated slot  772  is larger than the outer diameter of the front wheel axle  722 . The rectangular hole  774  is larger than the outer diameter of the rear wheel axle  732 . Thus, when the side plates  77  are driven by an external force, they can be moved alternatively up and down relative to the tilting seat  30 . As shown in  FIG. 7 , each side plate  77  further has a guide groove  776  located at an inner wall thereof. Each tread board  75  is coupled between the guide grooves  776  of the two side plates  77  by a guide rod  754 . The guide rod  754  has two opposite ends thereof respectively mounted with a guide roller  756  that is rotatably coupled to the guide groove  776  of one respective side plate  77  to enhance tread board moving stability, allowing the respective tread board  75  to be moved synchronously with the tread board adjustment frame  76 . 
     Referring to  FIGS. 4-8 , the tread board adjuster  80  comprises a third motor  81 , a third screw rod  82 , a third sleeve  79 , and an interlocking seat  83 . The third motor  81  is mounted at the tilting seat  30 . The third screw rod  82  has a front end thereof connected to the third motor  81 . The third sleeve  79  is threaded onto the third screw rod  82  with a bottom end thereof affixed to the interlocking seat  83 . Thus, when the third motor  81  is started to rotate the third screw rod  82  clockwise or counter-clockwise, the third sleeve  79  is caused by the third screw rod  82  to carry the interlocking seat  83  axially forwards or backwards along the third screw rod  82 . The tread board adjuster  80  further comprises two opposing linkages  84 . As illustrated in  FIG. 4 ,  FIG. 6  and  FIG. 8 , each linkage  84  comprises a front sliding rail  85 , a rear sliding rail  86 , a front sliding seat  87 , a rear sliding seat  88 , a bracket  89 , an upper sliding rail  90 , a lower sliding rail  91 , an upper sliding seat  92 , a lower sliding seat  93 , a first link  94 , and a second link  95 . The front sliding rail  85  is affixed to the tilting seat  30 . The rear sliding rail  86  is affixed to the tilting seat  30  opposite to the front sliding rail  85 . The front sliding seat  87  and the rear sliding seat  88  are respectively mounted on the front sliding rail  85  and the rear sliding rail  86 . The bracket  89  comprises a first prop rod  892 , and two second prop rods  894  arranged in parallel. The first prop rod  892  has opposing front and rear ends thereof respectively connected to the front sliding seat  87  and the rear sliding seat  88 . The second prop rods  894  have respective opposing front and rear ends thereof respectively connected to respective outer walls of the side plates  77  of the tread board adjustment frame  76  and the first prop rod  892 . The upper sliding rail  90  is affixed to a bottom side of the first prop rod  892  of the bracket  89  between the front sliding rail  85  and the rear sliding rail  86 . The lower sliding rail  91  is affixed to the tilting seat  30  to face toward the upper sliding rail  90 . The upper sliding seat  92  and the lower sliding seat  93  are respectively mounted at the upper sliding rail  90  and the lower sliding rail  91 . Further, the lower sliding seat  93  is connected to one end of the interlocking seat  83  (see  FIG. 4 ). Thus, the lower sliding seat  93  can be carried to move by the interlocking seat  83 . The first link  94  has opposing top and bottom ends thereof respectively pivotally connected to the first prop rod  892  of the bracket  89  and the lower sliding seat  93 . The second link  95  has opposing top and bottom ends thereof respectively pivotally connected to the upper sliding seat  92  and the tilting seat  30 . Further, the first link  94  and the second link  95  are pivotally connected together in a crossed manner. 
     Based on the above-described structural composition, if the user wishes to adjust the climb gradient, start up the first motor  41  to rotate the first screw rod  42 , thereby biasing the tilting seat  30  relative to the base frame  20 . At this time, subject to angular position change of the tilting seat  30 , the climb gradient is relatively changed. After reached the desired angle, turn off the first motor  41  to keep the tilting seat  30  in the adjusted angular position, and the user can thus step on the tread boards  75  to perform stair-climbing exercises on the desired climb gradient. 
     Because the angular position of the tilting seat  30  can be changed relative to the base frame  20 , in order to let the user hold the handrail  50  with the two hands under the ergonomic posture during the process the user is stepping on the tread boards  75 , the second motor  61  can be started up to rotate the second screw rod  62  in biasing the handrail  50  relative to the tilting seat  30  to a suitable angular position. After the tilting seat  30  reaches the desired angular position, turn off the second motor  61 , keeping the handrail  50  in the optimal angular position suitable for holding by the user&#39;s both hands. 
     On the other hand, the tread boards  75  can be slightly tilted with the change of the tilting seat  30  in the incline angle. In order to let the tread boards  75  to be constantly maintained in horizontal for stepping by the user as the angle of the tilting seat  30  is changed, the third motor  81  can be started up to rotate the third screw rod  82  in moving the lower sliding seat  93  via the interlocking seat  83 . When the lower sliding seat  93  is moved, the first link  94  and the second link  95  are biased relative to each other to move the bracket  89  upwards. At this time, the bracket  89  moves the tread board adjustment frame  76  upwards relative to the tilting seat  30  subject to matching between the front sliding seat  87  and the front sliding rail  85  and matching between the rear sliding seat  88  and the rear sliding rail  86 . During movement of the tread board adjustment frame  76 , the slide plates  77  are forced to bias the tread boards  75  relative to the tilting seat  30 , enabling the tread boards  75  to be maintained in horizontal after change of the incline angle of the tilting seat  30 , and allowing the user to conduct a stepping exercise with less effort. 
     In order to let the stair climbing machine  10  to be operated efficiently and conveniently, the tilting seat adjuster  40 , the handrail adjuster  60  and the tread board adjuster  80  can be controlled to work synchronously through an electronic control measure so that when changing the incline angle of the tilting seat  30 , the tread boards  75  or the handrail  50  can be relatively biased to the optimal angular position suitable for exercise. 
     In conclusion, the stair climbing machine  10  of the invention uses the tilting seat adjuster  40  to adjust the incline angle of the tilting seat  30  and the tread board adjuster  80  to adjust the horizontal angle of the tread boards  75 , enabling the user to conduct stair-climbing exercises at different climb gradients accurately and comfortably. Further, the stair climbing machine  10  uses the handrail adjuster  60  to adjust the incline angle of the handrail  50 , or employs an electronic control measure to actuate the tilting seat adjuster  40 , the tread board adjuster  80  and the handrail adjuster  60  synchronously, enabling the user to get good support in the operation, and achieving the objects of the present invention.

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