Patent Publication Number: US-7722507-B2

Title: Inclination controlling device of treadmill

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   The present application claims the benefit of Korea Patent application No. 2003-0011094 filed Feb. 21, 2003, which is hereby incorporated by reference in its entirety. 
   BACKGROUND OF THE INVENTION 
   I. Field of Invention 
   The present invention relates to an exercise apparatus in general and, more particularly, to an inclination controlling device of a treadmill and foldable treadmill using the same, the treadmill inclination angle can be controlled more widely including a downward inclination as well as an upward inclination in order to enable users to run or walk on the treadmill in various conditions. 
   II. Description of Related Art 
   A treadmill known as a running machine is widely used indoors such as at home or in a sports center as it allows users to have an effect of exercising while working or running on its endless rotating belt in a narrow space. Recently, the demand for treadmills is drastically increasing due to the advantages of its safety and convenience because users can exercise indoors using the treadmill even in the cold winter. 
   Users of a treadmill can strengthen their cardiopulmonary function and leg muscles, and can control their weight by consuming calories efficiently while running or walking on a treadmill. To maximize this exercise effect, a treadmill with an inclination controlling device has been produced lately. 
   A treadmill comprises a foot plate which upholds load resulting from users, a belt rotating endlessly around the footplate on which users can run or walk continuously, an operating motor for the belt, a holding post used as arm supports while exercising, an inclination controlling device which supports the load of the footplate and controls the inclination. 
   As illustrated in  FIG. 1 , the conventional treadmill  1  includes a support frame  10  which upholds weight or impact by running or walking thereon, a link member  20  pivotally connected to one end  11  of the support frame for rotating relative to the support frame  10 , a fixed member  30  which is connected to the support frame  10  to uphold a rear part of the support frame  10 , a base  40  pivotally connected to one end  21  of the link member  20  for rotating and settling on the ground, an actuator  50  which connects the base  40  with the link member  20 . 
   The fixed member  30  has one end  31  welded to a support frame  10 , the other end  32  which maintains a constant angle with a ground, and a roller  32   a  on the ground movable with a support frame  10  according to an operation of the actuator  50 . 
   The actuator  50  has one end  51   a  pivotally connected to a link member  20  for rotating relative to the link member  20  and can control an inclination angle of the support frame  10  by means of contracting or extending a bar  51  because the bar  51  controls an angle between the link member  20  and the base  40  thereby allowing the link member  2  to rotate relative to the base  40 . 
   In the conventional treadmill shown at  FIG. 1  as described above, the angle θ between the link member  20  and the base  40  gets smaller and the height of the joint  11  gets lower while the bar  51  of the actuator  50  is being contracted. On the contrary, while the bar  51  is being extended, the angle θ gets bigger and the height of a joint  11  gets higher. As a result, the treadmill can have various slope for running or walking. 
   However, the inclination controlling device of the conventional treadmill counts on a height deviation amount of the joint  11  caused by a rotation of the link member  20  in view of controlling the inclination angle of the support frame because the distance from the joint  11  to the ground is consistent regardless of operation of the actuator  50 . Therefore, the conventional treadmill is limited in that it cannot control the inclination angle in a wide range. 
   Besides, the fixed member  30  should be formed short to make a steep inclination angle in the conventional inclination controlling device. But in this case, the conventional treadmill cannot substantially provide a downward inclination because of the short length of the fixed member  30 . Moreover, in the case of the steep inclination of the support frame  10 , moments are concentrated near the actuator  50  thereby causing weakening of the durability of links. 
   SUMMARY OF INVENTION 
   As a solution for the above problem, the present invention is designed to provide an inclination controlling device of a treadmill, having an inclination angle that can be controlled in a wide range including a downward inclination, as well as an upward inclination in order to enable users to exercise in various exercise conditions. 
   Another purpose of the present invention is to provide an inclination controlling device of a treadmill with enhanced durability by means of preventing load or impact by users from being concentrated on a specific member. 
   The present invention also enables protection of joints (such as a knee joint) of users from excessive impact when using a treadmill. 
   To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, an inclination controlling device comprising a belt support frame, a first link member which is pivotally connected to the belt support frame, a second link member which is pivotally connected to the belt support frame and positioned at a regular interval from the first link member, a base which is pivotally connected to both the first link member and the second link member relatively for rotating, and an actuator to let the belt support frame move relative to the base frame is provided. 
   And thus, it enables control of the inclination of the belt support frame with a wider range because the inclination controlling device of the treadmill is formed as a four link structure pivotally connecting the belt support frame, the first link member, the base frame and second link member to one another. That is, a second pivotal joint connecting the belt support frame with the second link member goes down when a first pivotal joint connecting the belt support with the first link member goes up, and, likewise, the second pivotal joint goes up when the first pivotal joint goes down. Accordingly the inclination connecting the first pivotal joint with the second pivotal joint can be realized in a wider range. 
   In addition, due to the four-link structure with four pivotal joints, impact on a footplate during exercise can be absorbed in the pivotal joints or transformed to elastic energy in each member so that reactive impacts on a user&#39;s knee and ankle joint during exercise can be minimized. 
   Herein, it is preferable that the first link member is longer than the second link member because different lengths of the links connecting the belt support frame with the base frame permit the inclination to be controlled widely and easily. 
   It is desirable that the angle between the first link member and the base frame is an acute angle defined between 5° and 60° and the angle between the second link member and the base frame is defined between 75° and 90° when the first pivotal joint is positioned nearest to the base frame. 
   Moreover, when the first pivotal joint is positioned nearest to the base frame, the first pivotal joint is positioned lower than the second pivotal joint so that users can enjoy running or working on a downward inclination condition. 
   Besides, when the first pivotal joint is positioned furthest from the base frame, the first pivotal joint is higher than the second pivotal joint so that users can enjoy running or working on an upward inclination condition. 
   Herein, it is preferable that the angle between the first link member and the base frame is defined either between 35° and 50° or between 75° and 90°. When the angle between the first link member and the base frame is within the range between 0° and 45°, the first pivotal joint can be higher with an efficient rate. And when the angle between the first link member and the base frame reaches 90°, the steepest inclination is embodied. It can suit the user&#39;s taste in exercise through installing of the ranges of the angle in manufacturing process by adjusting the fit with conditions in advance in which the users want to exercise. 
   Also, in view of controlling the inclination angle of the belt support frame, it is desirable that the actuator is operated by contraction or extension of the bar, wherein the actuator is pivotally connected on the base frame and one end of the operating bar can be pivotally connected to one of the first link member, the second link member and the belt support frame. 
   Meanwhile, the actuator includes a motor, a pinion engaged with the motor and driven by the motor, and a transfer gear engaged with both the pinion and the first link member, wherein the transfer gear can be engaged with the second link member instead of the first link member. 
   The treadmill device has a holding post having a handle and the base frame is pivotally connected to the holding post for rotating relative to the holding post thereby enabling users to keep the treadmill folded in a narrow space when it is not in use. 
   On the other hand, the present invention provides a foldable treadmill comprising a footplate; an inclination controlling device including a belt support frame upholding the footplate and controlling an inclination angle of the footplate, a first link member pivotally connected to the belt support frame, a second link member pivotally connected to the belt support frame, a base frame pivotally connected to the first link member and the second link member respectively; a holding assembly including a holding post longitudinally set up, a support connected to the lower end of the holding post; a hinge formed at the holding assembly for letting said inclination controlling device rotate relative to the holding assembly. And thus, users can keep the treadmill folded in a narrow space when it is not in use. 
   It is preferable that the hinge is formed rotatably connecting the holding post with the base frame. 
   The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view illustrating an inclination controlling device of a conventional treadmill. 
       FIG. 2  through  FIG. 8  relates to an inclination controlling device of a treadmill in accordance with the first embodiment of the present invention. 
       FIG. 2  is a perspective view illustrating the inclination controlling device of a treadmill in accordance with the present invention. 
       FIG. 3  is an exploded view illustrating the inclination controlling device of a treadmill in accordance with the present invention. 
       FIG. 4  is a side view illustrating the inclination controlling device of a treadmill in accordance with the present invention. 
       FIG. 5  is a side view illustrating an upward inclination by the inclination controlling device of a treadmill in accordance with the present invention. 
       FIG. 6  is a side view illustrating a downward inclination by the inclination controlling device of a treadmill in accordance with the present invention. 
       FIG. 7  is a perspective view illustrating a treadmill with the inclination controlling device in accordance with the present invention. 
       FIG. 8  is a perspective view illustrating the treadmill folding the inclination controlling device. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
     FIG. 2  through  FIG. 8  illustrate a treadmill with an inclination controlling device in accordance with the first embodiment of the present invention that comprises a footplate  60 , a belt  70  that moves around the footplate endlessly, a motor  80  driving the belt to rotate via a connection belt  81 , and an inclination controlling device that upholds loads or impacts on the footplate  60  and controls an inclination angle of the footplate  60 . 
   Herein, the inclination controlling device  100  thereof has a belt support frame  110  which upholds the footplate  60  loaded by users, a first link member  120  pivotally connected to one side of the belt support frame  110  for rotating, a second link member  130  pivotally connected to the other side for rotating at a regular interval from first link member  120 , a base frame  140  pivotally connected to both the first link member  120  and the second link member  130  respectively, and an actuator  150  pivotally connected to the base frame  140  letting the controlled belt support frame  110  to move relative to the base frame  140 . 
   The belt support frame  110  has a rectangular form to securely hold the footplate  60  from loads and impacts. That is, protrusions  111  around four edges of the rectangular form in the belt support frame  110  are fit to convex portions  61  of the footplate  60 . 
   The first link member  120  includes a first pivot joint  121  which is pivotally connected to one side of the belt frame  110  for rotating, and a third pivot joint  123  which is pivotally connected to one side of the base frame  140  for rotating. 
   The second link member  130  includes a second pivot joint  132  which is pivotally connected to the belt support frame  110  at an interval of d 1  from the first pivot joint  121 , and a fourth pivot joint  134  which is pivotally connected to one side of the base frame  140  at an interval of d 2  relative to the base frame  140  for rotating. 
   Laid on the ground horizontally, the base frame  140  has a foldable hinge pivotally connected to one side of a holding assembly  90  thereby enabling the treadmill to be folded when it is not use. And the base frame  140  is connected to one side to the first link member  120  and to the second link member  130  at the interval of d 2  respectively. 
   The actuator  150  includes a driving part  151  and a bar  152  formed as a leadscrew whose one end is inserted into the driving part  151  and engaged with the driving part  151  in proper length. Therefore, as the driving part  151  rotates, the bar  152  gets contracted or extended according to the rotation direction of the driving part  151 . Herein, one end of actuator  150  (driving part  151 ) is pivotally connected to the base frame  140  and one end  152   b  of the bar  152  is pivotally connected to the belt support frame  110 , so that an inclination angle of the belt support frame  110  can be controlled as the driving part  151  rotates and the bar  152  gets contracted or extended. 
   As described above, the belt support frame  110 , the first link member  120 , the second link member and the base frame  140  make up a trapezoid-shaped four-link structure and rotate relative to each other. Preferably, the first link member  120  is much longer than the second link member  130  in order to control the inclination angle of the belt support frame  110  with a wider range, thereby attaining a steep inclination. 
   In the horizontal condition of the belt support frame shown in  FIG. 4 , it is preferred that the belt support frame  110  poses as low as possible. However, in the case that the belt support frame  110  poses too low in the horizontal condition, excessive stress could be concentrated on the first link member  120  and the bar  152 . Therefore, it is desirable to maintain the proper distance H between the belt support frame  110  and the ground. Concretely, the distance H is preferably 100 mm to 250 mm to satisfy both conditions properly. 
   In addition, during running or walking on a treadmill, most of the loads or impacts by a user are mainly concentrated on a front portion A of the belt support frame  110 . In the conventional inclination controlling devices  1 , such concentrated loads damage or trouble the treadmill, since the loads are transmitted and concentrated on the actuator  50  and the link members  20 . However, in the inclination controlling device in accordance with the first embodiment of the present invention, illustrated in  FIG. 4 , the loads Fp by a user are distributed to the first link member  120  and the bar  152 , respectively, as an amount of reaction force F 1 , Fa of a sine component of the angle α, γ. Furthermore, even though there is a little difference caused by values of angle α and the angle γ, the force component in a horizontal direction is set off and a moment does not work on the base frame  140 . That is, the inclination controlling device of the present invention makes external forces from the user shared effectively, and thus each member  110 , 120 , 130 , 140  making up the four-link structure has an improved durability thereby removing the possibility of breakage. Moreover, the inclination controlling device can be manufactured with reduced cost by applying a lower capacity of actuator  150  thereto, and users can run or walk on the treadmill with the inclination controlling device feeling more comfortable due to properly shared external forces. 
   It is also possible to design the ratio of d 1  over d 2  variously where d 1  is a distance from the first pivotal joint  121  to the second pivotal joint  132 , and d 2  is a distance from the third pivotal joint  123  to the fourth pivotal joint  134 . When d 1  is equal to d 2 , the external force will be distributed effectively, but this will cause the inclination angle to not be able to be controlled. That is, the belt support frame  110  is always parallel to the base frame  140 . When d 1  is much longer than the d 2 , the external force can not be shared effectively while the wide range of an inclination is angle can be controlled. Therefore, there exists an optimized ratio of d 1  over d 2  (d 1 /d 2 ). Preferably, the ratio of d 1  over d 2  is defined between 0.3 and 0.9 to harmonize both the control range of the inclination angle and the effective external load sharing. 
   It is desirable that the second link member  130  is pivotally fixed at a point which is very close to the end of base frame  140 . That is, d 4  shown in  FIG. 4  is defined between 25 mm and 80 mm in view of improving the load sharing characteristics and durability. 
   Referring to the  FIG. 2  through FIG.  6 ., components shown as  71 ,  72  are rollers to guide and drive the belt  70  to rotate endlessly around the footplate  60 , a component shown as  91  is a handle formed at the end of holding post  90 , and a component shown as  92   a  is a control panel showing exercise conditions. 
   Hereinafter, an operation mechanism in accordance with the first embodiment will be readily apparent by the following description referring to  FIG. 4  through  FIG. 6 . 
   Illustrated in  FIG. 6 , when the first pivotal joint  121  is positioned nearest to the base frame  140 , that is, when a length of the bar  152  of the actuator  150  is the shortest, a height of the first pivotal joint  121  is lower than that of the second pivotal joint  132  thereby realizing downward inclination by the inclination controlling device of a treadmill. Herein, an angle β between the second link member  130  and base frame  140  is 90° while an angle α between the first link member  120  and base frame  140  is an acute angle between 5° and 60°. More specifically, it is preferable that the angle α is defined between 5° and 30° in order to realize steeper downward inclination, and that the angle α is defined between 30° and 60° in order to realize steeper upward inclination. 
   Preferably, the angle β is less than 90° in that the second pivot joint  132  is getting higher and then lower when the second link member  130  is rotating over 90° thereby causing the footplate  60  to be fluctuated, which results in an concentration of stresses on the first link member  120  and the second link member  130 , causing unpleasantness to users. 
   As shown in  FIG. 5 , when the bar  152  is extended by operating the actuator  150 , the angle β gets smaller within the range less than 90° and the height of the second pivot joint  132  gets lower. Simultaneously, the angle α gets bigger and the height of the first pivot joint  121  gets higher. Accordingly, the inclination angle of the belt support frame  110  is converted to a plus value (upward inclination) from a minus value (downward inclination) as the bar  152  is extended, and then significantly steep upward inclination can be realized according to the extension amount of the bar  152 . 
   Herein, it is preferable that the angle α is defined either between 35° and 50° or between 75° and 90° when the bar  152  of the actuator  150  is extended maximally. More concretely, the first pivot joint  121  can be higher with an efficient rate for the amount of rotation Δα of the first link member  120  within the range between 0° and 45°. When the angle between the first link member and the base frame reaches 90°, the steepest slope is embodied. It can suit the user&#39;s taste in exercise through installing the ranges of α in the manufacturing process by adjusting the fit with conditions in advance in which users want to exercise. More specifically, when some users want to enjoy running in a downward inclination condition, as well as, an upward inclination, i.e. in the wide range of inclination angles, the maximum value of the angle α is preferably 45°. Likewise, when other users want to enjoy running or walking in a very steep upward inclination, the maximum value of the angle α is preferably 90°. 
   As the bar  152  of the actuator  150  gets extended, the belt support frame  110  moves in the direction of  110   b . That is, the belt support frame moves in the direction of  110   b  by a length of d 3 -d 3 ′ as the second link member  130  rotates by the amount of rotation (β. (Herein, d 3 ′ in  FIG. 5  becomes shorter than d 3  in  FIG. 6 ). Considering that users tend to move forward to grasp a handle  91  when the inclination of the footplate  60  goes up, the inclination controlling device  100  enables users to feel more comfortable and keep exercising on the footplate  60  even when the inclination of the footplate  60  is going up gradually. In general, the treadmill should be equipped with the footplate  60  long enough for the users&#39; exercise radius. Meanwhile the inclination controlling device can have a shorter footplate  60  by the length of d 3 -d 3 ′ when the inclination of the footplate  60  goes up, thereby saving a space for the treadmill. 
   The inclination controlling device  100  in accordance with the present invention provides versatility from a downward inclination to a significant steep upward inclination according to contraction or extension of the bar  152  so that user can feel more satisfaction with enjoying various exercise conditions. 
   As explained above, the inclination controlling device  100  in accordance with the present invention is formed as a four-link structure by pivotally connecting the belt support frame  110 , the first link member  120 , the second link member  130  and the base frame  140  to one another. Therefore, in controlling the inclination angle of the belt support frame, when the first pivot joint  121  is rising from the base frame  140 , the second pivot joint  132  is contrariwise dropping toward the base frame  140 . Likewise when the first pivot joint  121  is dropping toward the base frame  140 , the second pivot joint  132  is contrariwise rising from the base frame  140 , thereby controlling the inclination angle widely. 
   In addition, having the four-link structure with the four pivotal joints  121 , 123 , 132 , 134  pivotally connecting link members  110 , 120 , 130 , 140  to one another can absorb external impacts or forces on the footplate  60  during an exercise by transforming external impacts or forces into elastic energy of link members  110 , 120 , 130  bent slightly or damping on each pivotal joints  121 , 123 , 132 , 134 , thereby minimizing the reactive impacts on user&#39;s knee or ankle joint. 
   The actuator  150  also limits the movement of the four-link structure, as illustrated in the first embodiment where the actuator is pivotally connected to the base frame  140  and one end of the bar  152  is pivotally connected to the belt support frame  110 . Meanwhile, one end of the bar  152 , constituting an actuator, can be connected to either the first link member  120  or the second link member  130 , instead of the belt support frame  110  without any change of effect. 
   Although the current embodiment detailed above deals with inclination controlling device with a bar type actuator, as far as the four-link structure is included in the treadmill inclination controlling device, the present invention also includes an inclination controlling device manually operated with a handle, and an inclination controlling device applying other types of actuators comprising a pinion driven by a motor, a transfer gear engaged with both the pinion and the first link member (or the second link member) instead of bar type actuator. 
   As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.