Abstract:
A safety brake type rollator which is normally in detained state, but it starts to advance when releasing grips installed on both handle bars are gripped, is disclosed. The elaborate utilization of lever principle associated with power transmission between two ratchet wheels realizes innovative effect of the present invention.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to safety brake type rollator, and more particularly, to a rollator which is normally in detained state, but it starts to advance when releasing grips installed on both handle bars are gripped. The elaborate utilization of lever principle associated with power transmission between two follower blocks and ratchet wheels realizes innovative effect of the present invention. 
     2. Description of the Prior Art 
     A conventional rollator is used for helping a patient or disabled person&#39;s activity and assuring his/her security. Accordingly, braking means is indispensable especially for users who are suffering from gout or having trouble in their feet. A rollator should be constructed perfectly firm, secure, and reliable to avoid any possible accident. A braking means like that which applied for a bicycle is generally installed on a conventional rollator for the user to apply a force to braking means to both brake grips at two sides of a handle bar. 
     Incidentally it is hard for such a handicapped person to stop the rollator timely when an emergency arises, on the contrary. He/she might tumble down and involuntarily push forward the rollator in stead of stopping it by holding the brake grips so that causing a deplorable result. Such is the case that is often encountered by a conventionally designed rollator. 
     In order to overcome the shortcomings inherent to the conventional technique described above, the present inventor has delved into this matter with a long time efforts and came to realization of the present invention. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a safety brake type rollator having a stable and reliable structure which is normally in detained state unless releasing grips are gripped so as to ensure security of the rollator. 
     It is another object of the present invention to provide a safety brake type rollator whose braking effect can be adjusted to meet requirements of all kinds of users. 
     The above object can be achieved by a safety brake type rollator mainly comprising two handle bars each with a releasing grip, two foot bars, an arm rest, and a braking mechanism. The braking mechanism is constituted by two pulling wires each of them conjoined to each releasing grip with its upper end being hinged to a transmission rod at its lower end, the transmission rod is tightened to a serrated follower block below, and the follower block is further teeth combined with a ratchet wheel which is installed coaxially with a rear castor. Being exerted by the resilient force of a coil spring situated on the follower block, the follower block engages its teeth with the ratchet wheel so that the rollator can not move. As the releasing grips are gripped so as to release the downward force of the follower block, the engagement between the follower block and the ratchet wheel is loosened so that the rollator can be free to move. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are included to provide a fuller understanding of the invention and incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and together with the description serve to explain the principles of the invention wherein: 
     FIG. 1 is an exploded illustrative view of the present invention; 
     FIG. 2 is an entire contour view of the present invention; 
     FIG. 3 is a view showing that the brake mechanism of the present invention is at the released state by gripping the releasing grip; 
     FIG. 4 is an enlarged view of a part of the brake mechanism of the present invention at braked state; 
     FIG. 5 is a view showing that the rollator of the present invention is at the detained state; and 
     FIG. 6 is an enlarged view of a part of the braking mechanism of the present invention at released state. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2 simultaneously, a safety brake type rollator of the present invention mainly comprises two handle bars  10 ,  11 , two foot bars  12 ,  13 , an arm rest  14 , a brake mechanism  20 , two transmission rods  23 , two saddles  24 , two coil springs  25 , two follower blocks  26 , two ratchet wheels  30 , two front castors  15 , and two rear castors  15 ′. Two handle bars  10 ,  11  and two foot bars  12 ,  13  are hinged together by a hinged arm  32 , and a hinged joint H is formed at the top portion of each of the foot bars  12 ,  13  for engaging the arm rest  14  at both sides thereof. Two front castors  15  are respectively attached to the bottom ends of the handle bars  10 ,  11 ; while two rear castors  15 ′ are respectively attached to the bottom ends of the foot bars  12 ,  13 . 
     The brake mechanism  20  includes two releasing grips  21  installed respectively at the tips of both handle bars  10 ,  11 , each releasing grip  21  is provided with a pulling wire  22  fixed thereon which rests once on the side of the arm rest  14  before extending downward. 
     The transmission rod  23  is fixed at the opposite side of each hinged joint H with its one end, and tunneled through the saddle  24  and the coil spring  25  and finally engaged to the follower block  26  with its other end such that the coil spring  25  is sandwiched between the saddle  24  and the follower block  26  having a serrated bottom edge  27 . 
     Below the follower block  26 , there is a ratchet wheel  30  coaxially hinged together with the rear castor  15 ′, a plurality of teeth  31  are formed around the edge of the ratchet wheel  30 . 
     As shown in FIG. 4, a long guide slot  261  is formed longitudinally along the follower block  26 , and a slider  262  shorter than the guide slot  261  in length is fitted in the guide slot  261  such that it is slidable along longitudinal direction thereby enabling the follower block  26  to linearly reciprocate in the longitudinally direction. In addition, at both sides of the slider  262 , there are respectively provided guard plates  263 ,  264  fixed with fixing element such as set screws on the foot bars  11 ,  12  so as to prevent possible radial excursion of the follower block  26 . 
     FIGS. 4 and 5 are the drawings which illustrate the brake mechanism of the present invention is at the braked state. As shown in FIG. 4, the follower block  26  is pressed down by the coil spring  25  so as to engage its serrated edge  27  with the teeth  31  of the ratchet wheel  30  thereby detaining the rear castor  15 ′ not to move, at this time, the releasing grip  21  remains in undisturbed state without being gripped. 
     On the contrary, as shown in FIGS. 3 and 6, when the releasing grips  21  are gripped, the releasing wires  22  transmit a downward force to both sides of the arm rest  14  such that it is raised up according to lever principle with respect to the hinged joint H as a fulcrum. At this time each transmission rod  23  is also displaced upward with the result that the serrated edge  27  of the follower block  26  is separated from the teeth  31  of the ratchet wheel  30  thus releasing detention of the rear castor  15 ′. 
     Moreover, in order to appropriately adjust resiliency of each coil spring  25  as shown in FIGS. 4 and 6, the present invention further provides an adjustor block  28  for each transmission rod  23  with a through hole  281  for the rod  23  to pass through after the rod  23  tunnels through the coil spring  25  and then is fixed to the follower block  26 . A threaded hole  282  is provided in each adjustor block  28  for tightening it to the transmission rod  23  with a set screw  29 . With this construction, the position of the adjustor block  28  between the saddle  24  and the follower block  26  can be properly set hence in turn determines the position of the coil spring  25  and offer it different resilient force for various users to control the tension of the releasing wire  22  and the force to grip the releasing grip. 
     Besides, the foot bars  12 ,  13  are extendable and can be inclined so as to align the rear castor  15 ′ and the releasing grip  21  in the same vertical line to the ground as shown in FIGS. 3 and 5. By so the gravity center of the entire rollator can be kept stably in a lower position. 
     The safety brake type rollator of the present invention is much more advantageous in comparison with any conventional one in many respects, for example, the rollator of the present invention will never accidentally run uncontrolled even situated on a sloped surface unless the releasing grips  21  are gripped. Especially, when the arm rest  14  is accidentally pressed down, each transmission rod  23  will also displace downward so that it engages with the ratchet wheel  30  thereby detaining the rear castor  15 ′, that means achieving the braking effect. Besides, an adjustor block is provided for controlling the tension of each releasing wire  22  and gripping force of each releasing grip  21  for all kinds of users. In addition, the rear castor  15 ′ and the releasing grip  21  can be aligned in the same vertical line to the ground so that the gravity center of the rollator can be kept stably in a lower position. 
     Many changes and modifications in the above described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claims.