Patent Publication Number: US-6217056-B1

Title: Walking aid

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an improvement in a walking aid provided with wheels at the lower end of a stick. 
     2. Description of the Prior Art 
     A walking aid is known, comprising a stick body inclined in the forward-and-backward direction so that its lower end is positioned forward, a support rod installed so as to be branched from behind the stick body and inclined so that its lower end is positioned backward, and wheels provided on both sides of the lower end of the stick body and on both sides of the lower end of the support rod, steering being carried out by turning the stick body (refer to Japanese Laid-open Utility Model Application No. Sho 64-14019, for example). 
     In the case of the above-mentioned walking aid, the axle of the wheels of the stick body is secured to the stick body. Therefore, when the stick body tilts right or left, one of the wheels floats, and the stability of the stick body is Impaired. Furthermore, when the stick body is turned to perform steering operation, the inner wheel on the turning side is lowered, and the outer wheel is raised, since the stick body is inclined in the forward-and-backward direction. For this reason, when the steering operation is performed while the walking aid stands upright, the outer wheel floats. If the entire walking aid is tilted outward at this time, the outer wheel can make contact with the ground. However, in either case, the stability of the walking aid in the right-and-left direction is impaired, whereby the walking aid becomes difficult to use and unstable. In particular, tilting the walking aid outward is an unnatural action causing anxiety for the user. In addition, the stick body mainly has the walking aid function of the stick, and the support rod is used as an auxiliary member. Therefore, the ground contact conditions of the wheels on the support rod side have little effect on the above-mentioned stability. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a walking aid being stable and easy to use, without causing a problem of floating of the right and left wheels even when the stick body is tilted or steered. 
     In order to attain the above-mentioned object, the walking aid of the present invention comprises a stick body inclined in the forward-and-backward direction so that its lower end is positioned forward, a support rod installed so as to be branched from behind the stick body and inclined so that its lower end is positioned backward, and wheels provided on both sides of the lower end of the stick body and on both sides of the lower end of the support rod, steering being carried out by turning the stick body, wherein an axle installed at the lower end of the stick body and provided with the wheels on both sides thereof is supported rotatably with respect to its axis in the forward-and-backward direction. Therefore, even when the stick body is tilted or steered, the axle rocks automatically so that the wheels on both sides remain contact with the ground at all times, thereby not causing instability. 
    
    
     The specific structures of the walking aid in accordance with the present invention will be made clear by the explanations regarding embodiments described below. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view showing an embodiment of the walking aid of the present invention; 
     FIG. 2 is a partially cut-away front view showing the rocking mechanism of the walking aid; 
     FIG. 3 is a side view showing the rocking mechanism; 
     FIG. 4 is a vertical sectional front view showing the cylinder of the rocking mechanism; 
     FIG. 5 is a vertical sectional side view showing the cylinder; 
     FIG. 6 is a perspective view showing the rocking shaft of the rocking mechanism; 
     FIG. 7 is a perspective view showing the rocking stopper of the rocking mechanism; and 
     FIG. 8 is a side view showing the main portions of the link of the walking aid. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIG. 1, the numeral  1  represents a stick body inclined in the forward-and-backward direction so that its lower end is positioned forward, the numeral  2  represents a support rod installed so as to be branched from behind the stick body  1  and inclined so that its lower end is positioned backward, the numeral  3  represents front wheels disposed on both the right and left sides of the lower end of the stick body  1 , and the numeral  4  represents rear wheels disposed on both the right and left sides of the lower end of the support rod  2 . The numerals  5   u  and  5   d  represent brackets disposed at the upper and lower portions of the stick body  1 , respectively, the numeral  6  represents a bracket secured to the lower portion of the support rod  2 , and the numeral  7  represents a link formed of two members  7   a  and  7   b  connected with a pin shaft  9 . The upper end of the support rod  2  is rotatably connected to the bracket  5   u  with a pin shaft  10 , whereby the support rod  2  can be folded and unfolded with respect to the stick body  1 , and the link  7  is disposed between the bracket  5   d  and the bracket  6  and connected thereto with pin shafts  11  and  12 . Therefore, as a whole, a triangle, extending upward, is formed of the stick body  1 , the support rod  2  and the link  7 . By moving the portion around the pin shaft  9  upward so as to fold the link  7  in the reverse V-shape, the support rod  2  can be folded to the position wherein the support rod  2  becomes nearly parallel with the stick body  1 . 
     The numeral  13  represents a grip disposed at the upper end of the stick body  1 , and the numeral  14  represents a hook. The user holds the grip  13  with a hand, and moves as the wheels  3  and  4  rotate. The stick body  1  is made rotatable with respect to the brackets  5   u  and  5   d . By turning the stick body  1  right and left, steering can be carried out. The stick body  1  shown in FIG. 1 is turned left. The numeral  15  represents a walking aid having the above-mentioned structure. 
     A rocking mechanism  21  is disposed at the installation portion of the front wheels  3 . In FIG.  2  and the following figures, the numeral  22  represents a cylinder, the numeral  23  represents a rocking shaft, the numeral  24  represents an axle, the numeral  25  represents a rocking stopper, and the numeral  26  represents a fixture pin. 
     As shown in FIGS. 4 and 5, the inner upper portion of the cylinder  22  is a large-diameter portion  22   a , and the inner lower portion thereof is a small-diameter portion  22   b . The large-diameter portion  22   a  has a size into which the stick body  1  can be fitted. A pair of rocking shaft support holes  22   c  passing crosswise through the small-diameter portion  22   b  and a pair of axle insertion holes  22   d  also passing crosswise therethrough are formed so as to be perpendicular to each other in the small-diameter portion  22   b . The support holes  22   c  are round holes having a diameter aligned to the outer diameter of the rocking shaft  23 . The insertion holes  22   d  are slot holes extending vertically, and the short diameter of the insertion hole  22   d  is slightly larger than the outer diameter of the axle  24 . As shown in FIG. 6, at the center of the rocking shaft  23 , an axle hole  23   a  is disposed so as to pass through the rocking shaft  23  in a direction perpendicular to the longitudinal direction of the rocking shaft  23 . 
     At the time of assembly, first, the lower end of the stick body  1  is inserted into the large-diameter portion  22   a  of the cylinder  22  until it makes contact with the small-diameter portion  22   b . At this time, the orientation of the cylinder  22  is selected so that the axle insertion holes  22   d  are directed in the right-and-left direction of the stick body  1 . The stick body  1  is secured by using fixture holes  22   e  formed in the large-diameter portion  22   a  and the fixture pin  26  passing through a through hole  1   a  formed in the stick body  1  in the right-and-left direction so as to be aligned with the fixture holes  22   e . This pin  26  is also used to install the rocking stopper  25  as described later. 
     Next, the rocking shaft  23  is inserted into the support holes  22   c  of the cylinder  22 . The axle  24  is passed through the axle insertion holes  22   d  and the axle holes  23   a  so that both ends of the axle  24  evenly project on both sides of the stick body  1 . The wheels  3  and  3  are then secured to both ends of the axle  24 . As a result, the rocking shaft  23  can rock freely in the range wherein the axle  24  is restricted by the axle insertion holes  22   d . Therefore, the axle  24  of the front wheels  3  is supported rotatably with respect to its axis in the forward-and-backward direction. Even when the stick body  1  is tilted or steered, the axle  24  rocks automatically so that the wheels  3  and  3  on both sides remain in contact with the ground at all times. This does not cause instability due to floating of one of the wheels, whereby it is possible to obtain a stable, easy-to-use walking aid  15 . 
     The above-mentioned embodiment is an example of a rocking mechanism for rotatably supporting an axle with respect to its axis in the forward-and-backward direction. It is thus possible to use mechanisms having other appropriate structures. 
     In the case when baggage is hung on the hook  14  of the stick body  1 , or when the walking aid  15  is desired to remain standing upright, for example, the rocking function can be stopped by using the rocking stopper  25 . In other words, as shown in FIG. 7, the rocking stopper  25  is provided with an operation lever  25   a  and a pair of installation pieces  25   b  disposed on both sides of the lever  25   a  so as to hold the cylinder  22  therebetween. The installation piece  25   b  is provided with a fixture hole  25   c , and a dent portion  25   d  for holding the axle is formed at the lower fringe of the installation piece  25   b . This rocking stopper  25  is rotatably installed on the stick body  1  by using the fixture pin  26  inserted through the holes  25   c  as shown in FIG.  2 . When the operation lever  25   a  is pushed down as shown in solid lines in FIG. 3, the dent portion  25   d  makes contact with the axle  24 . Therefore, the axle  24  is stopped from moving in the vertical direction, and cannot rock. On the other hand, when the operation lever  25   a  is pushed up as shown in chain lines, the axle  24  is released from the dent portion  25   d , and can rock. As a result, even when the user has baggage, he can hang it on the stick body  1 , and can walk while being supported by the walking aid  15 . In this respect, it is also possible to obtain an easy-to-use walking aid. 
     The above-mentioned embodiment is an example of a structure for temporarily stopping the rocking function. It is thus possible to use other appropriate structures. 
     The walking aid  15  of the present invention is used while the support rod  2  is unfolded backward as shown in FIG.  1 . In the case when the walking aid  15  is not used or in other cases, the support rod  2  can be folded by bending the link  7  in the reverse V-shape. In the present invention, the link  7  is improved to enhance usability. FIG. 8 shows an example of the structure. 
     In other words, the upper fringe  7   c  of the member  7   b  is bent toward the member  7   a , and a projection  7   d  for angular adjustment is formed at the end of the upper fringe  7   c . With this structure, even when the support rod  2  is unfolded, the projection  7   d  makes contact with the upper fringe of the member  7   a , and the link  7  is not made completely straight, but remains in a gently-sloped reverse V-shape with the portion of the pin shaft  9  raised slightly. For this reason, in the present invention, it is not necessary to use a spring to fold the support rod  2 . When all the wheels  3  and  4 , or the wheels  3  or  4  are detached from the ground by lifting the stick body  1  or by tilting it forward or backward, a force pushing the portion of the pin shaft  9  upward is applied because of the weights of the portions detached from the ground, whereby the support rod  2  is folded spontaneously. 
     However, if the height of the reverse V-shape is set too high, the support rod  2  is folded unintentionally even when the wheels are detached slightly from the ground. This makes the walking aid difficult to use, and makes the user feel restless, and causes an adverse mental effect. To solve this problem, the structure is designed so that the support rod  2  is not folded immediately after the wheels are detached from the ground, and so that the support rod  2  is folded only when the support rod  2 , the link  7  and the like are slightly tapped in the folding direction. This can be achieved by properly selecting the size of the projection  7   d  in consideration of the balance among the weights of the components and the friction at the shaft portions. As a result, an easy-to-use walking aid can be obtained by using a simple mechanism. This feature cannot be achieved by a structure using a spring for folding. 
     The above-mentioned embodiment is an example of a mechanism for maintaining the link  7  in a gently-sloped reverse V-shape. It is thus possible to use other appropriate structures.