Abstract:
A flexible transmission device utilizes two flexible cables or ropes to pass through a narrow passage and connect two operating elements. An extendable mechanism is an intermediate of the two flexible elements. The extendable mechanism includes two tubes co-axially linked to each other. The two flexible elements overlap in the extendable mechanism in a free moving condition, which allows the relative distance between the two operating elements changing. When a flexible element is pulled from an operating member, a slider connected between the two flexible elements will be biased to fasten the two flexible elements so that the drag force can be transmitted to the second operating member.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention generally relates to a flexible transmission device, and more particularly relates to a flexible transmission device in which a cable or rope is used to pass through a narrow passage and connect two operating elements, so that a drag force can always be transmitted even when the relative distance between the two operating elements being changed. 
     2. Related Art 
     Using a flexible element, such as a cable or rope, to transmit a drag force is a well-known art. For example, a brake for a bicycle or a motorcycle generally uses a steel cable to transmit an operation force from a brake lever. Many foldable baby strollers, such as disclosed in U.S. Pat. Nos. 5,765,885; 5,769,447; 5,882,030; 5,622,377 and so on, use a similar flexible transmission device for releasing a latch mechanism for the folding-up purpose. The flexible device includes a steel cable for remotely pulling a latch mechanism or the like and releasing a foldable portion of the stroller. 
     In the aforesaid prior arts, the steel cable is loosely enclosed in a flexible tube, such as a plastic tube or a scrolled-wire tube. The flexible tube is fixed at both ends to the frame structure for guiding the steel cable moving therein responding to the operation. The two ends of the cable link respectively to an operation lever and an actuating member, such as a brake or latch. Since the elements on both ends of the cable are generally adjustable with relative positions, for instance, the brake lever of a bicycle will change its relative position or distance to the brake along with the height adjustment of the handle. Likewise, the control lever of a stroller will change its relative position or distance to the latch mechanism along with the folding operation of the frame. In the prior arts, the change of relative distance or position makes the flexible tube change its shape, such as the curve thereof. The different curve bending won&#39;t influence the function, but it requires a certain length and space for the bending. Therefore, in the prior arts, the flexible cable and tube has to be long enough and loosely fixed outside the frame. 
     The aforesaid flexible cable and tube fixed outside a frame will not suitable for some foldable devices, especially when a compact structure is an important objective. For example, a foldable stroller is intended to be smaller when being folded. The length of the tube has to be shortened, which may constrain the operation of cable when being bent too much. Or, the bending causes inconvenience and bad looks of folding. 
     If we try to enclose the flexible cable and tube in the frame, such as the tube of the bicycle or stroller, then the limited space of the tube will constrain the bending of the cable, and make the solution unworkable. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a flexible transmission device, which allows the change of length in the flexible elements. 
     Another object of the present invention is to provide a flexible transmission device, which can be enclosed in a limited space, such as a tube, and allows the change of length in the flexible elements. 
     The present invention uses flexible elements to link two operating members. When the relative distance between the two operating members changes, the flexible elements are still workable for transmitting a drag force. 
     To achieve the aforesaid objects, a flexible transmission device according to the present invention includes two flexible elements each having one end linking to an extendable mechanism, and each other end linking to a remote operating member respectively. The extendable mechanism includes a first tube and a second tube coaxially linking with each other so that the second tube is movable inside the first tube for changing the relative position or length of the two tubes that connect to the aforesaid two flexible elements respectively. In other words, when the two operating members linking at ends of the flexible elements change their relative positions, the extendable mechanism will change its length accordingly. The two flexible elements are defined as a first and a second flexible element. The first flexible element fixedly mounted along the axial direction of the extendable mechanism, with one end fixed to a first operating member, and the other end fixed to a slider movable along the second flexible element. The slider will be temporarily tilted to fix on the second flexible element when being pulled by the first flexible element so as to transmit the drag force. The second flexible element is fixed inside the extendable mechanism with one end fixed to the movable second tube, and the other end to the second operating member. The second flexible element can be moved in the axial direction of the extendable mechanism along with the axial length change of the extendable mechanism. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow illustration only, and thus are not limitative of the present invention, and wherein: 
     FIG. 1 is an exploded view of a flexible transmission device according to the present invention; 
     FIG. 2 is a sectional view of the present invention showing the components in a normal state; 
     FIG. 3 is a sectional view of the present invention showing the components in another normal state where the length of the extendable mechanism is shortened; 
     FIG. 4 is a sectional view of the present invention showing the components in a working state where the flexible elements are seized and moved to transmit drag force; and 
     FIG. 5 is an exploded view of another embodiment of a flexible transmission device according to the present invention showing another kind of a retaining element. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention uses flexible elements, such as cables, ropes or the like, to link two operating members. When the relative distance between the two operating members changes, the flexible elements are still workable for transmitting a drag force. 
     As shown in FIG.  1  and FIG. 2, a flexible transmission device according to the present invention mainly includes an extendable mechanism  10 , a first and a second flexible element  20 ,  30  each having one end linking to the extendable mechanism  10 , and the other end linking to the remote operating members  60 ,  70  respectively. The extendable mechanism  10  includes a first tube  11  and a second tube  12  coaxially linking with each other so that the second tube  12  is movable inside the first tube  11  for changing the relative position or length of the two tubes  11 ,  12 , that connect to the aforesaid two flexible elements  20 ,  30  respectively. In other words, when the two operating members  60 ,  70  linking at ends of the flexible elements  20 ,  30  change their relative positions, the extendable mechanism  10  will change its length accordingly. 
     There are means for adjusting the length of the extendable mechanism  10 , i.e., the relative position of the first tube  11  and the second tube  12 . The adjusting means include a plurality of positioning holes  81  formed on the second tube  12 ; a movable pin  80  radially passing through a hole formed on the first tube  11  and being selectively fixed into one positioning hole  81  of the second tube  12 ; and a retaining element  82  for normally keeping the movable pin  80  in any a positioning hole  81 . 
     The first and second flexible elements  20 ,  30  are steel cables, ropes or other similar elements. The first flexible element  20  is fixed with one end to a first operating member  60 , and the other end to a slider  40 . The slider  40  is sleeved on and movable along the second flexible element  30 . One end of the second flexible element  30  is fixed to the second operating member  70 . The slider  40  will be temporarily tilted to grasp the second flexible element  30  when being pulled by the first flexible element  20 . So that, the drag force of the first operating member  60  can be transmitted, via the first flexible element  20 , the slider  40  and the second flexible element  30  to the second operating member  70 . 
     The first flexible element  20  is movable inside the first tube  11  of the extendable mechanism  10 . The second flexible element  30  is fixed inside the extendable mechanism  10  with one end fixed to the movable second tube  12 , and the other end to the second operating member  70 . When the drag force is applying from the first operating member  60 , the first flexible element  20  and the second flexible element  30  will seize together for transmitting the force to the second operating element  70 . 
     In a normal condition, the second flexible element  30  and the slider  40  can be relatively moved since there is a suitable gap between the second flexible element  30  and a through hole of the slider  40 . A retaining element  50  mounting on the second flexible element  30  is used to press the slider  40  and always straighten the overlapped length of the two flexible elements  20 ,  30  for being ready to transmit drag force. The retaining element  50  normally supports the slider  40  in an idle position free from firm contact with the flexible element  30  by maintaining a circular gap between the two. The retaining element  50  is a resilient element, such as a spring as shown in FIG. 1, or a plurality of resilient pearls as shown in FIG.  5 . One end of the retaining element  50  is fixed to a portion, for example on one end of a core  111 , of the first tube  11 , which is relatively fixed to the first operating member  60 . The other end of the retaining element  50  is fixed to the slider  40  to normally support it in an straightened position as shown in FIG.  2 . One end of the second flexible element  30  is fixed to and pulled by the second operating member  70 . The other end of the second flexible element  30  is mounted through a sleeve  121 , which is fixed to one end of the second tube  12 . So that, the second flexible element  30  is straightly extended and can be moved in the axial direction of the extendable mechanism  10  along with the axial length change of the extendable mechanism  10 . 
     The slider  40  is sleeved on the second flexible element  30 . The slider  40  can be freely moved on the second flexible element  30  so as to adjust itself and maintain the straight extending conditions of the first flexible elements  20  when the first tube  11  and the second tube  12  of the extendable mechanism  10  are relatively changed of their positions. As shown in FIG. 3, when the user releasing the movable pin  80  and moving the second tube  12  inwards the first tube  11  to shorten the length of the extendable mechanism  10 , the retaining element  50  will support the slider  40  moving along the second flexible element  30  so as to maintain the first flexible element  20  in the straightened position. 
     In the same way, when the user releasing the movable pin  80  and moving the second tube  12  outwards the first tube  11  to lengthen the length of the extendable mechanism  10 , the retaining element  50  will also support the slider  40  moving along the second flexible element  30  so as to maintain the first flexible elements  20  in the straightened position. 
     As shown in FIG. 4, when the user operating the first operating member  60 , for example, moving a trigger  61 , to apply a drag force to the slider  40  through the first flexible element  20 , the slider  40  will be biased to catch the second flexible element  30  and pull it moving. In this moment, the retaining element  50  is pressed and bent since the drag force of the first flexible element  20  generating a moment to the slider  40 , which is caused by the different centering lines of the two flexible elements  20 ,  30  passing through the slider  40 . When the slider  40  is biased on the second flexible element  30 , the sharp rims of the hole of the slider  40  where the second flexible element  30  passing through will seize on the flexible element  30  and firmly grasp it. Therefore, the first flexible element  20  will pull the second flexible element  30  and the second operating member  70  to achieve a certain function, such as releasing a latch  71  as shown. 
     The aforesaid embodiments of flexible transmission device according to the present invention can be applied to a device having a foldable frame or an adjustable frame. For example, the first and second tubes  11 ,  12  of the extendable mechanism  10  can be the handle bar and the main frame of a stroller. In a bicycle, the first and second tubes  11 ,  12  can be the brake handle and the main frame of the bicycle where the two elements are relatively adjustable with their positions. 
     In conclusion, the present invention uses flexible elements, such as cables, ropes or the like, to link two operating members. When the relative distance between the two operating members changes, the flexible elements are still workable for transmitting a drag force. The flexible transmission device can be applied to a device having a foldable frame or an adjustable frame, for example, a handle bar and a foldable frame of a stroller, or a brake lever and the frame of a bicycle, where a drag force can still be transmitted when the two elements are relatively adjustable with their positions. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.