Patent Publication Number: US-9839571-B2

Title: Foldable rollator

Description:
FIELD 
     The present disclosure relates generally to the technical field of rehabilitation-assisted instrument, and specifically to a foldable rollator. 
     BACKGROUND 
     At present, with the population aging in China, the aged people are increasing gradually. For these aged people, especially those suffering from mobility problems caused by disease, they have more and more difficulties in walking since their physical functions are gradually decreasing. In this case, there is an increasing demand for a portable and sturdy walker which is convenient to park. However, most walkers on the market are only able to be folded only once, causing huge sizes, so these walkers are not convenient for carrying, transportation and storage. In order to address the above problem, some walkers that can be folded secondly are presented. However, for such walker, the secondary folding generally requires the user to bend down and squat to adjust a switch to do the folding operation. Such action is very difficult for normal users, especially aged people who have difficulties in walking, and meanwhile, there is a potential safety problem. 
     SUMMARY 
     Based on this, an objective of the present disclosure is to provide a foldable rollator, which is convenient for secondary folding, and easy to operate to save physical power, with safety and durability, in order to overcome the defects in the prior art. 
     According to the objective of the present disclosure, a foldable rollator is provided, including a folding device, a first rollator body and a second rollator body both of which are arranged in a mirror mode with respect to each other and movably connected with each other through the folding device, wherein each of the first and second rollator bodies includes a gripping part, a drawing device and a supporting fastener, the gripping part includes a supporting bar, the drawing device is arranged on the supporting bar and positioned away from the supporting fastener, the gripping part is rotatably connected to the supporting fastener, the supporting fastener is provided with a first clamping groove and a second clamping groove, the gripping part is perpendicular to and fixed to the supporting fastener when the drawing device is clamped in the first clamping groove, and the gripping part is rotationally connected to the supporting fastener when the drawing device is clamped in the second clamping groove. 
     The technical solution according to the present disclosure will be further explained as below. 
     In one embodiment, the folding device includes a first connecting rod, and a second connecting rod rotatably fixed to the first connecting rod, the first connecting rod and the second connecting rod are arranged to cross each other, both ends of the first connecting rod are rotatably fixed to the first rollator body and the second rollator body respectively, and both ends of the second connecting rod are rotatably fixed to the first rollator body and the second rollator body respectively. 
     In one embodiment, the gripping part includes a hand grip, the supporting bar includes an inner supporting bar and an outer supporting bar, the outer supporting bar is a hollow tubular structure, the inner supporting bar is slidably fixed inside the outer supporting bar, and the hand grip is fixed on the inner supporting bar and positioned on an end of the inner supporting bar away from the outer supporting bar. 
     In one embodiment, the gripping part further includes a rotating member detachably fixed on an end of the outer supporting bar, the rotating member is provided with an annular slot, the annular slot is arranged on an end of the rotating member close to the outer supporting bar, and the outer supporting bar is clamped in the annular slot. 
     In one embodiment, the rotating member is provided with a long hole and a sliding groove, the drawing device includes a drawing handle fixed on the outer supporting bar, a drawing bar arranged inside the sliding groove and connected to the drawing handle, a spring arranged inside the long hole and connected to the drawing bar, and a detent connected to the spring. 
     In one embodiment, the supporting fastener is provided with a curved groove fitted with the rotating member, each of both inner walls of the curved groove is provided with the first clamping groove and the second clamping groove respectively, each of the both inner walls of the curved groove is further provided with an arc segment, and the first clamping groove and the second clamping groove are connected with each other through the arc segment. 
     In one embodiment, each of both outer sides of the rotating member is provided with a convex part respectively, a side wall of the curved groove is provided with a mounting through hole, and the convex part is rotatably fixed inside the mounting through hole. 
     In one embodiment, a long groove penetrating the rotating member is arranged near the convex part, the detent is slidably arranged in the long groove, both ends of the detent extend out of the long groove, and the long hole, the sliding groove and the long groove are in communication with each other sequentially. 
     In one embodiment, the foldable rollator further includes a supporting platform including a first supporting tube, a second supporting tube arranged oppositely to the first supporting tube, and a flexible supporting member fixed on the first supporting tube and the second supporting tube, the first supporting tube and the second supporting tube are fixed on the folding member, and the flexible supporting member is provided with a drawing part. 
     In one embodiment, the foldable rollator further includes wheels, and a braking device arranged on the gripping part, the gripping part further includes a braking handle, and the braking device includes a braking housing, a clamp housing, a clamp, a limit push rod, a braking rod, a braking pad and a braking component; 
     one end of the braking component is connected to the braking handle, the other end of the braking component is connected to the clamp housing, the braking pad cooperates with the wheels, the clamp housing is arranged inside the braking housing, the clamp is arranged inside the clamp housing, the clamp housing includes a first housing and a second housing in threaded connection with each other, an inverted-conical cavity is arranged at the bottom of the interior of the clamp housing, the clamp is provided with an inverted-conical part matching with the inverted-conical cavity, the limit push rod is arranged at the bottom of the interior of braking housing, one end of the braking rod is arranged inside the clamp housing, and the other end of the braking rod is connected to the braking pad; when the braking device is in a first state, one end of the limit push rod abuts against the clamp, and is positioned inside the clamp housing, the inverted-conical cavity is separated from the inverted-conical part, and the clamp is opened; and when the braking device is in a second state, the limit push rod is separated from the clamp and positioned outside the clamp housing, the inverted-conical cavity matches with the inverted-conical part, and the clamp is closed to clamp the braking rod. 
     In one embodiment, a clamp pressure bar and a first compression spring are further arranged inside the clamp housing, the clamp pressure bar is arranged between the clamp and the first compression spring, and both ends of the first compression spring abut against the clamp pressure bar and the second housing respectively. 
     In one embodiment, a second compression spring is further arranged inside the braking housing, the second compression spring is sleeved on the second housing, and both ends of the second compression spring abut against the first housing and the braking housing respectively. 
     In one embodiment, a limit step is arranged inside the braking housing, one end of the limit push rob abutting against the clamp is arranged above the limit step, and the bottom of the first housing abuts against the limit step. 
     In one embodiment, a flange is provided on the periphery of the limit push rob, and a fixing groove matching with the flange is arranged at the bottom of the interior of the braking housing. 
     In one embodiment, the clamp includes a first clamping part and a second clamping part arranged in a symmetrical manner, a clamping portion is arranged on an opposite side of each of the first clamping part and the second clamping part respectively, and the first clamping part and the second clamping part match with each other to clamp the braking bar. 
     In one embodiment, the braking housing includes a first braking housing and a second barking housing arranged in a symmetrical manner. 
     The present disclosure has the following advantages. 
     The primary folding of the above foldable rollator in the transverse direction can be implemented by the folding device. Then the secondary folding of the above foldable rollator can be implemented by a user who is in standing through operating the drawing device fixed on the gripping part with the user&#39;s fingers so that the gripping part rotates from the first clamping groove to the second clamping groove about the supporting fastener to engage with the supporting fastener. In this way, it avoids the requirement of the user to bend down and squat to do the similar operations, which spends too much physical power. The folding operations of such foldable rollator is very convenient for the user, especially aged people who have difficulties in walking, which saves physical power and is safe and reliable, to remove potential security problems. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a structural schematic diagram illuminating a foldable rollator according to one embodiment of the present disclosure. 
       FIG. 2  is a side view showing a first rollator body according to one embodiment of the present disclosure. 
       FIG. 3  is a partial enlarged view showing the A portion of the foldable rollator according to one embodiment of the present disclosure. 
       FIG. 4  is structural schematic diagram illuminating a first rollator body according to one embodiment of the present disclosure. 
       FIG. 5  is a partial enlarged view showing the B portion of the foldable rollator according to one embodiment of the present disclosure. 
       FIG. 6  is a schematic diagram illuminating a first folding state of the foldable rollator according to one embodiment of the present disclosure. 
       FIG. 7  is a schematic diagram illuminating a second folding state of the foldable rollator according to one embodiment of the present disclosure. 
       FIG. 8  is an exploded diagram of a braking device according to one embodiment of the present disclosure. 
       FIG. 9  is a schematic diagram illuminating a first state of the braking device according to one embodiment of the present disclosure. 
       FIG. 10  is a schematic diagram illuminating a second state of the braking device according to one embodiment of the present disclosure. 
    
    
     DESCRIPTION OF REFERENCE SIGNS 
       100  folding device,  120  first connecting rod,  130  second connecting rod,  140  supporting platform,  150  first supporting tube,  160  second supporting tube,  170  flexible supporting member,  180  drawing part,  200  first rollator body,  300  second rollator body,  400  gripping part,  420  hand grip,  440  inner supporting bar,  460  outer supporting bar,  480  rotating member,  482  convex part,  484  long groove,  485  annular slot,  486  long hole,  487  sliding groove,  490  braking handle,  500  drawing device,  520  drawing handle,  540  drawing bar,  560  spring,  580  detent,  600  supporting fastener,  620  fixed part for front-wheel,  640  fixed part for rear-wheel,  660  curved groove,  662  first clamping groove,  664  arc segment,  666  second clamping groove,  670  mounting through hole,  680  wheel,  700  braking device,  712  second compression spring,  714  limit step,  720  clamp housing,  722  inverted-conical cavity,  724  clamp pressure bar,  726  first compression spring,  727  first housing,  728  second housing,  730  clamp,  732  inverted-conical part,  734  first clamping part,  736  second clamping part,  740  limit push rod,  750  braking rob,  760  braking pad, and  777  braking component. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following description of embodiments, reference is made to the accompanying drawings which form a part hereof, and in which it is shown by way of illustration specific embodiments of the disclosure that can be practiced. It is to be understood that other embodiments can be used and structural changes can be made without departing from the scope of the disclosed embodiments. 
     As shown in  FIGS. 1 and 4-6 , a foldable rollator is provided, including a folding device  100 , a first rollator body  200  and a second rollator body  300  both of which are arranged in a mirror image orientation with respect to each other and movably connected with each other through the folding device  100 . Each of the first and second rollator bodies  200 ,  300  includes a gripping part  400 , a drawing device  500  and a supporting fastener  600 , the gripping part  400  includes a supporting bar, the drawing device  500  is arranged on the supporting bar and positioned away from the supporting fastener  600 , the gripping part  400  is rotatably connected to the supporting fastener  600 , the supporting fastener  600  is provided with a first clamping groove  662  and a second clamping groove  664 , when the drawing device  500  is clamped in the first clamping groove  662 , the gripping part  400  is perpendicular to and fixed to the supporting fastener  600 , and when the drawing device  500  is clamped in the second clamping groove  600 , the gripping part  400  is rotationally connected to the supporting fastener  600 . 
     The primary folding of the above foldable rollator can be implemented by the folding device. Specifically, the first rollator body  200  and the second rollator body  300  may be folded and fit together in the transverse direction through the folding device  100 , when the user only draws the middle position of the folding device  100 . Since the drawing device  500  is arranged on the supporting bar and positioned on one end of the supporting bar away from the supporting fastener  600 , that is, the drawing device  500  is arranged at a position very close to the hand of the user, when the gripping part  400  is clamped in the first clamping groove  662 , that is the gripping part  400  is perpendicular to and fastened on the supporting fastener  600 , the foldable rollator is in use, and when the user is in a standing posture, the secondary folding of the foldable rollator in the longitudinal direction can be implemented by drawing and operating the drawing device  500  fixed on the gripping part  400  with the user&#39;s fingers so that the gripping part  400  rotates from the first clamping groove  662  to the second clamping groove  66  about the supporting fastener  600  to be close to the supporting fastener  600  and engage with the supporting fastener  600 . In this way, it avoids the requirement of the user to bend down and squat to do the similar operations, which spends too much physical power. The folding operations of such foldable rollator is very convenient for the user, especially aged people who have difficulties in walking, which saves physical power and is safe and reliable, to remove potential security problems. 
     As an alternate embodiment, the drawing device for the secondary folding of the foldable rollator may be arranged on the hand grip  420 , which may further facilitate the standing operation, to improve the convenience of the use of the foldable rollator, leading to a better user experience. 
     The folding device  100  includes a first connecting rod  120 , and a second connecting rod  130  rotatably fixed to the first connecting rod  120 . The first connecting rod  120  and the second connecting rod  130  are arranged to cross each other, both ends of the first connecting rod  120  are rotatably fixed to the first rollator body  200  and the second rollator body respectively  300 , and both ends of the second connecting rod  130  are rotatably fixed to the first rollator body  200  and the second rollator body  300  respectively. In this preferred embodiment, each of the first connecting rod  120  and the second connecting rod  130  is composed of segments of certain rod pieces. The connection of these rod pieces may be implemented through pins in a rotatable manner. The first connecting rod  120  and the second connecting rod  130  intersect one another to form an X shape The first connecting rod  120  and the second connecting rod  130  are connected and held together using the pins inserted through each of the first connecting rod  120  and the second connecting rod. Meanwhile both ends of each of the first connecting rod  120  and the second connecting rod  130  are fixed on the first rollator body  200  and the second rollator body  300  respectively. When a user draws the middle position of the folding device  100 , the first rollator body  200  and the second rollator body  300  may be folded and fit together in the transverse direction through the rotation and fitting of the first connecting rod  120  and the second connecting rod  130  with respect to each other. The advantage of such design is that it is very convenient for folding and fitting the first and second rollator bodies together through the connecting rod structure to achieve the primary folding of the foldable rollator in the transverse direction, without assembling and disassembling any member. In addition, such folding structure is easy for operation, and low in cost. 
     The above folding device further includes a supporting platform  140  including a first supporting tube  150 , a second supporting tube  160  arranged oppositely to the first supporting tube  150 , and a flexible supporting member  170  fixed on the first and second supporting tubes  150 ,  160 , the first and second supporting tubes  150 ,  160  are fixed on the folding member  100 , and the flexible supporting member  170  is provided with a drawing part  180 . The primary folding may be implemented by the user through drawing the drawing device  180  to drive the first and second supporting tubes  150 ,  160  so that the first connecting rod  120  and the second connecting rod  130  move towards each other to close up. When the foldable rollator is in the folding state, the flexible supporting member  170  is fixed between the first and second supporting tubes  150 ,  160 , so as to hang below the first and second supporting tubes  150 ,  160  or lie on the first and second supporting tubes  150 ,  160 . This allows greatly saving space. When the foldable rollator is unfolded in use, the flexible supporting member  170  is rotatably unfolded through the first and second supporting tubes  150 ,  160 , to become a form of supporting structure for the supporting platform  140 , which facilitates the user who is tired after a long walk to take a rest through sitting on the supporting platform  140 , or facilitates the storage of some everyday items, such as water bottle, key and access card, without carrying them, so as to lighten loads. 
     As shown in  FIG. 2 , the gripping part  400  further includes a hand grip  420 , the supporting bar includes an inner supporting bar  440  and an outer supporting bar  460 , the outer supporting bar  460  is a hollow tubular structure, the inner supporting bar  440  is slidably fixed inside the outer supporting bar  460 , and the hand grip  420  is fixed on the inner supporting bar  440  and positioned on an end of the inner supporting bar  440  away from the outer supporting bar  460 . The hand grip  420  is fixed on the end of the inner supporting bar  440 , and the inner supporting bar  440  slidably fixed inside the outer supporting bar  460  to scale, so it is convenient to adjust the height of the hand grip  420  according to the height of the user, and the user can use the foldable rollator in a comfortable position, to avoid bending down for operation which may cause physical power consumption and thus body aches and pains. 
     The gripping part  400  further includes a rotating member  480  detachably fixed on an end of the outer supporting bar  460 , the rotating member  480  is provided with an annular slot  485 , the annular slot  485  is arranged on an end of the rotating member  480  close to the outer supporting bar  460 , and the outer supporting bar  460  is clamped in the annular slot  485 . The steady engagement between the rotating member  480  and the outer supporting bar  460  can be implemented by providing the annular slot  485  on the end of the rotating member  480  facing towards the outer supporting bar  460 , so that the foldable rollator has good overall structural strength. 
     As shown in  FIG. 3 , the rotating member  480  is provided with a long hole  486  and a sliding groove  487 , the drawing device  500  includes a drawing handle  520  fixed on the outer supporting bar  460 , a drawing bar  540  arranged inside the sliding groove  487  and connected to the drawing handle  520 , a spring  560  arranged inside the long hole  486  and connected to the drawing bar  540 , and a detent  580  connected to the spring  560 . It is convenient for the foldable rollator to use in practice that the drawing handle  520  is arranged at a height for the convenience of touching when the user is in a standing posture. That is, the drawing handle  520  may be drawn by the user to drive the drawing bar  540  to move upwards, the spring  560  may be driven by the drawing bar  540  to be under compression, and the detent  580  may be driven by the elastic force of the spring  560  to slide inside the long groove  484 , so that each of the rotating member  480  and the supporting fastener  600  is in an active state, to rotate with respect to each other. Such transmission structure is simple and reliable, and easy to implement. 
     A long groove  484  penetrating the rotating member is arranged near the convex part  482 , the detent  580  is slidably arranged in the long groove  484 , both ends of the detent  580  extend out of the long groove  484 , and the long hole  486 , the sliding groove  487  and the long groove  484  are in communication with each other sequentially. The detent  580  is slidably fixed inside the long groove  484 , and both ends of the detent  580  extend out of the long groove  484 , so when the foldable rollator is in use, the relative positions of the gripping part  400  and the supporting fastener  600  can be fixed to prevent the separation between the gripping part  400  and the supporting fastener  600  caused by mis-shifted which may affect the normal use and cause a security problem. Meanwhile, the long hole  486 , the sliding groove  487  and the long groove  484  are in communication with each other sequentially to form a channel, so it is convenient to mount the drawing device  500 , and it makes various components of the drawing device  500  move accordingly, to implement the folding of the foldable rollator in the longitudinal direction. 
     As shown in  FIG. 5 , the supporting fastener  600  is provided with a curved groove  660  fitted with the rotating member  480 , each of both inner walls of the curved groove  660  is provided with the first clamping groove  662  and the second clamping groove  666  respectively, each of the both inner walls of the curved groove  660  is further provided with an arc segment  664  respectively, and the first clamping groove  662  and the second clamping groove  666  are connected with each other through the arc segment  664 . In this preferred embodiment, each of the both inner walls of the curved groove  660  is provided with the first clamping groove  662 , the arc segment  664  and the second clamping groove  666  respectively, and are symmetrically arranged in a mirror image orientation with respect to one another, so that both sides of the detent  580  can be fixed to ensure the stability of the connection. In practice the rotating member  480  is inserted into the curved groove  660 , and at this time, the detent  580  is inserted into the first clamping groove  662 , that is the gripping part  400  is perpendicular to the supporting fastener  600 . When the foldable rollator needs to be folded after using, the drawing handle  520  may be drawn upwards to drive the detent  580  to move upwards to disengage from the first clamping groove  662 , and then the gripping part may be rotated, so that the detent  580  slides along the arc segment  664  to slowly move to the second clamping groove  666 . The detent  580  then may be clamped in the second clamping groove  666  through the resilience force of the spring  560 , so that the rotating member  480  and the supporting fastener  600  can be fixed with respect to each other. Due to the elastic force of the spring  560 , the detent  580  may be ensured to slide along the arc segment  664  with closely fitting with the arc segment  664 , to complete the secondary folding. The above operations are convenient and efficient, and save both time and effort. 
     Each of both outer sides of the rotating member  480  is provided with a convex part  482  respectively, a side wall of the curved groove  660  is provided with a mounting through hole  670 , and the convex part  482  is rotatably fixed inside the mounting through hole  670 . The rotating member  480  is arranged at the end of the outer supporting bar contacting with the supporting fastener  600 , and the convex part  482  is arranged on the side of the rotating member  480  contacting with the supporting fastener  600  to fit and be connected to the mounting hole provided on the supporting fastener  600 , so it can achieve the rotation of the gripping part  400  to complete the secondary folding. In this preferred embodiment, the convex part  482  is provided with a threaded hole. The convex part  482  may be inserted into the mounting through hole  670  to be fastened with a screw or bolt, to ensure high stability of the connection between the rotating member  480  and the supporting fastener  600 , to guarantee high overall strength of the foldable rollator. In other embodiments, other connection modes can be used, within the scope of the present disclosure. 
     Further, as shown in  FIGS. 8-10  with continued reference to  FIGS. 1 and 2 , in one embodiment, the above foldable rollator further includes wheels  680 , and a braking device  700  arranged on the gripping part  400 , the gripping part  400  further includes a braking handle  490 , and the braking device  700  includes a braking housing  710 , a clamp housing  720 , a clamp  730 , a limit push rod  740 , a braking rod  750 , a braking pad  760  and a braking component  770 . 
     One end of the braking component  770  is connected to the braking handle  490 , the other end of the braking component  770  is connected to the clamp housing  720 , the braking pad  760  cooperates with the wheels  680 , the clamp housing  720  is arranged inside the braking housing  710 , the clamp  730  is arranged inside the clamp housing  720 , the clamp housing  720  includes a first housing  727  and a second housing  728  in threaded connection with each other, an inverted-conical cavity  722  is arranged at the bottom of the interior of the clamp housing  720 , the clamp  730  is provided with an inverted-conical part  732  matching with the inverted-conical cavity  722 , the limit push rod  740  is arranged at the bottom of the interior of braking housing  710 , one end of the braking rod  750  is arranged inside the clamp housing  720 , and the other end of the braking rod  750  is connected to the braking pad  760 ; when the braking device  700  is in a first state, one end of the limit push rod  740  abuts against the clamp  730 , and is positioned inside the clamp housing  720 , the inverted-conical cavity  722  is separated from the inverted-conical part  732 , and the clamp  730  is opened; and when the braking device  700  is in a second state, the limit push rod  740  is separated from the clamp  730  and positioned outside the clamp housing  720 , the inverted-conical cavity  722  matches with the inverted-conical part  732 , and the clamp  730  is closed to clamp the braking rod  750 . 
     When the foldable rollator is travelling, the braking device  700  is in the first state, and at this time, the inverted-conical cavity  722  is separated from the inverted-conical part  732 , and the clamp  730  is in an opening state; and when the foldable rollator is braked, the braking handle may be turned upwards under external force, the braking component  770  may move upwards with the braking handle, and the clamp housing  720  may move upwards with the action of the braking component  770 . After a certain displacement of the clamp housing  720 , the inverted-conical cavity  722  of the clamp housing  720  may contact the inverted-conical part  732  of the clamp, and may continue to move upwards with the clamp housing  720 , and the braking device  700  is in the second state (i.e., braking state). In this state, the clamp  730  may be under the action of the first compression spring, the inverted-conical cavity  722  may quickly fit the inverted-conical part  732 , the clamp housing  720  may clamp the clamp  730 , the clamp  730  may move upwards with the clamp housing  720 , the limit push rod  740  may be separated from the clamp  730 , the clamp  730  may clamp the braking rob  750  to move upwards together, and the braking rob  750  may act on the braking pad  760  to stop the wheels, achieve the purpose of quick braking. Due to the action of the resilient of both of the second compression spring  712  and the first compression spring  726 , the clamp housing  720  and the clamp  730  may move downwards quickly, the clamp  730  may contact the limit push rod  740  firstly, the limit push rod  740  may stop the movement of the clamp  730 , the clamp housing  720  may continue to move downwards to the limit step under the action of the second compression spring  712 , the clamp  730  may be separated from the clamp housing  720  quickly, the clamp  730  may be opened, the braking rob  750  may be released, and the foldable rollator may continue to run. 
     As shown in  FIG. 1 , the above wheels  680  include a front wheel and a rear wheel. The supporting fastener  600  further includes a fixed part for front-wheel  620  and a fixed part for rear-wheel  640 . The front wheel may be rotatably fixed on the fixed part for front-wheel  620 , and the rear wheel may be rotatably fixed on the fixed part for rear-wheel  640 . Two front wheels and two rear wheels are symmetrically mounted on the first rollator body  200  and the second rollator body  300 , to ensure the travelling of the foldable rollator more steadily. In other embodiment, a structure with two wheels, three wheels or other appropriate numbers of wheels may be used, within the scope of the present disclosure. For the structure with three wheels, it includes one front wheel and two rear wheels arranged in a triangular configuration. The front wheel may be rotatably fixed on supporting fastener  600  through mounting a bearing, so that it is convenient to change the traveling direction of the foldable rollator with more convenience and less physical power, which is convenient for the operation of the aged people. In addition, in order to avoid the collision between the braking pad  760  and the feet during travelling, the braking pad  760  is preferably mounted on the fixed part for rear-wheel  640 . 
     As shown in  FIGS. 9 and 10 , in one embodiment, a clamp pressure bar  724  and a first compression spring  726  are further arranged inside the clamp housing  720 , the clamp pressure bar  724  is arranged between the clamp  730  and the first compression spring  726 , and both ends of the first compression spring  726  abut against the clamp pressure bar  724  and the second housing  728  respectively. When the braking handle is adjusted to turn upwards for braking, the clamp housing  720  may move upwards under the action of the braking component  770 . Since the first compression spring  726  is under compression, the first compression spring  726  may apply downward pressure on the clamp  730  through the clamp pressure bar  724 , to make the inverted-conical part  732  of the clamp  730  quickly fit the inverted-conical cavity  722  of the clamp housing  720 , to achieve the closure of the clamp  730  so that the clamp  730  clamp the braking rod  750  to move upwards together. The braking rod  750  may act on the braking pad  760  to stop the wheels, to achieve quick braking. When the braking handle is released, since the first compression spring  726  is under compression, the first compression spring  726  may move downwards quickly. The first compression spring  726  may apply downward pressure on the clamp  730  through the clamp pressure bar  724 , making the clamp  730  move downwards quickly so that the clamp  730  contacts the limit push rod  740 , and the clamp  730  may be separated from the clamp housing  720  quickly, to achieve the opening of the clamp  730 . The braking rod  750  may be released to improve the sensitivity of the braking device  700 . 
     In one embodiment, a second compression spring  712  is further arranged inside the braking housing  710 , the second compression spring  712  is sleeved on the second housing  728 , and both ends of the second compression spring  712  abut against the first housing  727  and the braking housing  710  respectively. Since the second compression spring  712  is under compression, when the braking handle is released, the second compression spring  712  may apply downward pressure on the clamp housing  720 , the inverted-conical cavity  722  of the clamp housing  720  may fit the inverted-conical part  732  of the clamp  730 , to make the clamp housing  720  and the clamp  730  quickly move downwards together. The clamp  730  may contact the limit push rod  740  firstly, the clamp  730  may stop moving, the second compression spring  712  may make the clamp housing  720  continue to move to the limit step, the clamp  730  may be separated from the clamp housing  720  quickly to achieve the opening of the clamp  730 , and the braking rob  750  may be released to improve the sensitivity of the braking device  700 . 
     Referring back to  FIG. 8  with continued reference to  FIGS. 9 and 10 , the clamp  730  includes a first clamping part  734  and a second clamping part  736  arranged in a symmetrical manner, a clamping portion is arranged on an opposite side of each of the first clamping part  734  and the second clamping part  736  respectively, and the two clamping parts match with each other to clamp the braking bar  750 . The closure or opening of the clamp  730  may be implemented by the first clamping part  734  and the second clamping part  736 . The clamping portion is arranged on an opposite side of each of the first clamping part  734  and the second clamping part  736  respectively, and each of the two clamping portion is preferably a symmetrical groove matching with the periphery of the braking rob  750 , to prevent the braking rob  750  from swinging freely within the clamp  730 . The opposite side of each of the first clamping part  734  and the second clamping part  736  does not pass through the center of the inverted-conical part  732 , to improve the clamping force of the clamp  730  on the braking rob  750 , to make the braking system more stable. 
     Further, the clamp housing  720  may include a first housing  727  and a second housing  728 . One end of the first housing  727  is provided with a inverted-conical cavity  722 . One end of the second housing  728  is arranged on the other end of the first housing  727 . The clamp housing  720  is composed by the first housing  727  and the second housing  728 . The first housing  727  and the second housing  728  are connected through a screw thread, to facilitate the disassembling and replacing of the braking system. 
     In addition, in one embodiment, a limit step  714  is arranged inside the braking housing  710 , one end of the limit push rod  740  abutting against the clamp  730  is arranged above the limit step  714 , and the bottom of the first housing  727  abuts against the limit step  714 .When the braking handle is released, both of the clamp housing  720  and the clamp  730  move downwards. Since the end of the limit push rod  740  abutting against the clamp  730  is arranged above the limit step  714 , the clamp  730  may contact the limit push rod  740  firstly, the limit push rod  740  may stop the movement of the clamp  730 , the clamp housing  720  may continue to move downwards, the clamp  730  may be separated from the clamp housing  720 , the clamp  730  may be opened, the braking rod  750  may be released, and the clamp housing  720  may stop move after moving to contact the limit step  714 . The periphery of the limit push rod  740  is provided with a flange, and a fixing groove matching with the flange is arranged at the bottom of the interior of the braking housing  710 . When the clamp  730  moves downwards to abut on the limit push rod  740 , due to the limit function of the limit push rod  740 , the clamp  730  may be stopped to move downwards, so that the clamp  730  is separated from the clamp housing  720 . In another embodiment, the braking housing includes a first braking housing and a second barking housing arranged in a symmetrical manner, so it is convenient for the disassembling and replacing of the braking device  700 . 
     Technical features of the above embodiments may be combined arbitrarily. For brief description, not all of the possible combinations of the technical features of the above embodiments are described, but it will be appreciated that these possible combinations belong to the scope of the present disclosure once there is no conflict between the technical features. 
     The above are embodiments of the present disclosure described in detail, and should not be deemed as limitations to the scope of the present disclosure. It should be noted that variations and improvements will become apparent to those skilled in the art to which the present disclosure pertains without departing from its spirit and scope. Therefore, the scope of the present disclosure is defined by the appended claims.