Abstract:
A hand brake device for a wheeled cart includes a pivot pin, and a brake lever including a lever portion, a front lower portion with a rounded integral projection, and a curved slot unit for receiving the pin slidably. Upward movement of the lever portion about the pin can result in braking of the cart, which will be freed upon release of the lever portion. Downward movement of the lever portion about the projection can also result in the braking of the cart, which will be maintained unless an external force is applied to the lever portion.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a hand brake device, more particularly to a hand brake device for a wheeled cart. 
     2. Description of the Related Art 
     Referring to FIG. 1, a conventional hand brake device  1  is shown to be mounted on a handle  2  of a wheeled cart, such as a stroller or a wheelchair (not shown) and comprises a housing  10 , a brake lever  20 , and a cable pull rod  30 . The housing  10  includes a mounting portion  11  sleeved fixedly on the handle  2  of the wheeled cart, and a receiving portion  12  formed integrally with and disposed under the mounting portion  11 . The brake lever  20  has a front end portion that is provided with a fixed positioning member  21  and that is disposed within the receiving portion  12  of the housing  10 , and a lever portion  22  that extends rearwardly from the front end portion and that projects from the housing  10 . The positioning member  21  has one end pivotally connected to the housing  10  by means of a first pivot pin  13 , and the other end formed with upper and lower retaining portions  211 ,  212 . The pull rod  30  is mounted in the receiving portion  12  of the housing  10 , extends transverse to the brake lever  20 , is disposed behind the positioning member  21  of the brake lever  20 , and has an upper end pivotally connected to the housing  10  by means of a second pivot pin  14 , a lower end connected fixedly to a brake cable  3 , and an intermediate portion formed with an upper protrusion  31  and a lower protrusion  32 . 
     In a normal operating condition of the cart, the upper and lower protrusions  31 ,  32  of the cable pull rod  30  are disposed between the upper and lower retaining portions  211 ,  212  of the positioning member  21  of the brake lever  20 , and the lever portion  22  of the brake lever  20  extends parallel to the handle  2  of the cart. 
     Referring to FIG. 2, when the lever portion  22  of the brake lever  20  is turned toward the handle  2  of the cart, the lower retaining portion  212  of the positioning member  21  moves to abut against the lower protrusion  32  of the pull rod  30 , thereby pushing the pull rod  30  to move rearwardly. The pull rod  30 , in turn, pulls the brake cable  3  so as to result in a braking action on the cart. The hand brake device  1  is disposed at a first braking position at this time. When the lever portion  22  of the brake lever  20  is released, the restoring force of the brake cable  3  pulls the pull rod  30  and the lever portion  22  of the brake lever  20  to their original positions shown in FIG. 1, thereby restoring the cart to a normal operating condition. 
     Referring to FIG. 3, when the lever portion  22  of the brake lever  20  is turned away from the handle  2  of the cart, the upper retaining portion  211  of the positioning member  21  moves past the upper protrusion  31  of the pull rod  30 , and is retained in a groove between the upper and lower protrusions  31 ,  32  of the pull rod  30  so as to push the pull rod  30  rearwardly. The pull rod  30 , in turn, pulls the brake cable  3  so as to result in the braking action on the cart. The hand brake device  1  is disposed at a second braking position at this time. Even if the lever portion  22  of the brake lever  20  is released at this moment, the braking of the cart is still maintained until an external force is applied to the lever portion  22  of the brake lever  20 , thereby restoring the pull rod  30  and the lever portion  22  to their original positions shown in FIG. 1, and thereby restoring the cart to its normal operating condition. 
     Although the conventional hand brake device  1  can achieve its intended purpose, however, in actual use, the conventional hand brake device  1  is found to have the following disadvantages: 
     1. Since the brake lever  20  and the pull rod  30  are connected pivotally to the housing  10  at two different positions by two independent pivot pins  13 ,  14  during assembly, elements of the hand brake device  1  are increased. 
     2. Referring to FIG. 4, although the lever portion  22  of the brake lever  20  can be turned to a large extent relative to the handle  2  of the cart, displacement (L) of the lower retaining portion  212  of the positioning member  21  of the brake lever  20  during braking of the cart is relatively small such that rearward displacement of the pull rod  30  and the brake cable  3  is not large, thereby reducing effectiveness of the hand brake device  1 . 
     3. Since the first braking position of the hand brake device  1  is frequently applied to the cart, the lower retaining portion  212  of the positioning member  21  and the lower protrusion  32  of the pull rod  30  are easily susceptible to wearing. 
     SUMMARY OF THE INVENTION 
     Therefore, the object of the present invention is to provide a hand brake device that is capable of overcoming the aforementioned drawbacks of the prior art. 
     According to the present invention, a hand brake device is adapted to be mounted on a handle of a wheeled cart having a brake cable. The hand brake device comprises a housing, a brake lever, and a cable pull rod. The housing includes a mounting portion adapted to be sleeved fixedly on the handle, and a hollow receiving portion connected fixedly to and disposed under the mounting portion. The receiving portion includes a front wall, two opposite lateral walls extending integrally and rearwardly from the front wall, and a pivot pin fixed in the receiving portion. The front wall has an inner wall surface that is formed with a curved limiting groove, and a bottom portion that is formed with a through hole therethrough, which is adapted to permit extension of the brake cable into the receiving portion through the through hole. The brake lever includes a pivot connecting portion, a lever portion, and a positioning block. The pivot connecting portion is disposed within the receiving portion of the housing, and has a front lower portion formed with a rounded integral projection. The lever portion extends integrally and rearwardly from the pivot connecting portion, and projects from the housing. The positioning block is connected fixedly to the front lower portion of the pivot connecting portion. The rounded integral projection of the pivot connecting portion is received fittingly within the curved limiting groove in the front wall of the housing so as to permit rotation of the lever portion of the brake lever about the rounded integral projection in a direction away from the handle. The positioning block has an abutment surface and a retaining groove, which are disposed-above and behind the rounded integral projection of the pivot connecting portion and which define a rearwardly extending protrusion therebetween. The pivot connecting portion is formed with a curved slot unit that is disposed above and behind the rounded integral projection and that has a closed front end and a closed rear end. The pivot pin of the housing extends through the rear end of the curved slot unit such that the brake lever can be turned upwardly and downwardly, thereby moving the lever portion toward and away from the handle. The cable pull rod is disposed within the receiving portion of the housing, and is located behind and abuts against the positioning block. The cable pull rod has a top end sleeved rotatably on the pivot pin of the housing, a lower end adapted to be connected fixedly to and pulled forwardly by an end of the brake cable, and a retaining portion for engaging the retaining groove in the positioning block. When the lever portion of the brake lever is turned upwardly, engagement between the retaining portion of the cable pull rod and the retaining groove and location of the pivot pin within the rear end of the curved slot unit are maintained such that the positioning block pushes the cable pull rod to turn rearwardly so as to rotate the brake lever about the pivot pin, thereby moving the rear end of the brake cable rearwardly for braking the cart, after which, upon release of the lever portion of the brake lever, the brake cable pulls and moves the lower end of the cable pull rod forwardly to engage the rounded integral projection of the brake lever within the curved limiting groove in the front wall of the housing. When the lever portion of the brake lever is turned downwardly, the lever portion of the brake lever rotates about the rounded integral projection of the pivot connecting portion such that the pivot pin slides from the rear end of the curved slot unit to the front end of the curved slot unit so that the retaining portion of the cable pull rod separates from the retaining groove in the positioning block to move past the rearwardly extending protrusion of the positioning block so as to engage the abutment surface of the positioning block, thereby pulling and moving the rear end of the brake cable rearwardly for braking the cart and thereby preventing further rotation of the brake lever about the rounded integral projection, after which the brake lever can be turned upwardly toward the handle only when an external force is applied to the lever portion of the brake lever. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which: 
     FIG. 1 illustrates a handle of a wheeled cart incorporating a conventional hand brake device; 
     FIG. 2 illustrates the first braking position of the conventional hand brake device; 
     FIG. 3 illustrates the second braking position of the conventional hand brake device; 
     FIG. 4 illustrates how the conventional hand brake device operates when braking the cart; 
     FIG. 5 illustrates a handle of a wheeled cart incorporating the preferred embodiment of a hand brake device of the present invention; 
     FIG. 6 is an exploded perspective view of the preferred embodiment; 
     FIG. 7 is a partly sectional view of the preferred embodiment in an assembled state; 
     FIG. 8 illustrates the first braking position of the preferred embodiment; and 
     FIG. 9 illustrates the second braking position of the preferred embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 5 to  7 , the preferred embodiment of a hand brake device  5  according to the present invention is shown to be adapted to be mounted on a handle  7  of a wheeled cart (not shown) having a brake cable  6 , and comprises a housing  50 , a brake lever  60 , a curved cable pull rod  70 , and a cable guiding plug  80 . 
     The housing  50  includes a mounting portion  51  adapted to be sleeved fixedly on the handle  7 , and a hollow receiving portion  52  formed integrally with and disposed under the mounting portion  51 . The receiving portion  52  includes a front wall  521 , two opposite lateral walls  522  extending integrally and rearwardly from the front wall  521 , and a pivot pin  523  fixed between the lateral walls  522  of the receiving portion  52 . The front wall  521  has an inner wall surface that is formed with a curved limiting groove  524  (see FIG.  7 ), and a bottom portion that is formed with a through hole  525  therethrough so as to permit extension of the brake cable  6  into the receiving portion  52  through the through hole  525 . 
     The brake lever  60  includes a pivot connecting portion  61 , a lever portion  62 , a positioning block  63 , and two fixing pins  64 . The pivot connecting portion  61  is disposed within the receiving portion  52  of the housing  50 , has a front lower portion formed with a rounded integral projection  613 , and is formed with a curved slot unit  612  that is disposed above and behind the rounded integral projection  613  and that has a closed front end and a closed rear end. In this embodiment, the pivot connecting portion  61  includes two parallel, vertical plates  611 , each of which is formed with a curved slide slot  612 ′ that has a closed front end  6121 ′ and a closed rear end  6122 ′, and each of which has a front lower portion formed with an integral lobe projection  613 ′ and a pair of aligned pin holes  614 ′. The curved slide slots  612 ′ in the vertical plates  611  constitute the curved slot unit  612 . The closed front ends  6121 ′ of the slide slots  612 ′ constitute the closed front end of the slot unit  612 . The closed rear ends  6122 ′ of the slide slots  612 ′ constitute the closed rear end of the slot unit  612 . The integral lobe projections  613 ′ of the vertical plates  611  constitute the rounded integral projection  613  on the front lower portion of the pivot connecting portion  61 . 
     The lever portion  62  of the brake lever  60  extends integrally and rearwardly from the pivot connecting portion  61 , and projects from the housing  50 . The integral lobe projections  613 ′ of the vertical plates  611  of the pivot connecting portion  61  are received fittingly within the curved limiting groove  524  in the inner wall surface of the front wall  521  of the housing  50  so as to permit rotation of the lever portion  62  about the integral lobe projections  613 ′ in a direction away from the handle  7 . 
     The positioning block  63  of the brake lever  60  is connected fixedly between the integral lobe projections  613 ′ of the vertical plates  611 , and has an abutment surface  631  and a retaining groove  632 , which are disposed above and behind the integral lobe projections  613 ′ of the vertical plates  611  of the pivot connecting portion  61  and which define a rearwardly extending protrusion  633  there between, and two opposite sidewalls  635  (only one is visible in FIG. 6) that abut against the vertical plates  611 , respectively. The positioning block  63  is formed with two spaced-apart holes  634 . 
     The fixing pins  64  are press-fitted respectively within the pin holes  614 ′ in the vertical plates  611 , and extend respectively through the holes  634  in the positioning block  63  so as to connect fixedly the positioning block  63  to the integral lobe projections  613 ′ of the vertical plates  611  of the pivot connecting portion  61 . The pivot pin  523  extends through the rear ends  6122 ′ of the slide slots  612 ′ in the vertical plates  611  of the pivot connecting portion  61  of the brake lever  60  such that the brake lever  60  can be turned upwardly and downwardly, thereby moving the lever portion  62  toward and away from the handle  7 . 
     The curved cable pull rod  70  (see FIGS. 6 and 7) is disposed within the receiving portion  52  of the housing  50  and between the vertical plates  611  of the brake lever  60 , and is located behind and abuts against the positioning block  63 . The cable pull rod  70  has a top end  72  sleeved rotatably on the pivot pin  523  of the housing  50 , a lower end  73  adapted to be connected fixedly to and pulled forwardly by an end of the brake cable  6 , and a retaining portion  71  for engaging the retaining groove  632  in the positioning block  63  of the brake lever  60 . 
     The cable guiding plug  80  (see FIG. 6) is inserted fixedly into the through hole  525  in the bottom portion of the front wall  521  of the housing  50 , and has a guide hole  801  for guiding the brake cable  6  into the receiving portion  52  of the housing  50 . 
     Referring once again to FIG. 7, under normal operating condition of the cart, the pivot pin  523  is positioned at the closed rear ends  6122 ′ of the slide slots  612 ′ in the vertical plates  611  of the brake lever  60 , the integral lobe projections  613 ′ engage the limiting groove  524  in the inner wall surface of the front wall  521  of the housing  50 , and the retaining portion  71  of the cable pull rod  70  engages the retaining groove  632 in the positioning block  63  of the brake lever  60  so that the lever portion  62  of the brake lever  60  is generally parallel to the handle  7  of the cart at this time. 
     Referring to FIG. 8, when the lever portion  62  of the brake lever  60  is turned upwardly toward the handle  7  of the cart, engagement between the retaining portion  71  of the cable pull rod  70  and the retaining groove  632  in the positioning block  63  and location of the pivot pin  523  within the rear ends  6122 ′ (see FIG. 6) of the slide slots  612 ′ in the vertical plates  611  of the pivot connecting portion  61  of the brake lever  60  are maintained such that the positioning block  63  pushes the cable pull rod  70  to turn rearwardly so as to rotate the brake lever  60  about the pivot pin  523  and so as to separate the integral lobe projections  613 ′ of the brake lever  60  from the limiting groove  524  in the inner wall surface of the front wall  521  of the housing  50 , thereby moving the rear end of the brake cable  6  rearwardly for braking the cart. The hand brake device  5  is positioned at a first braking position at this moment. Upon release of the lever portion  62  of the brake lever  60 , the restoring force of the brake cable  6  pulls and moves the lower end  73  of the cable pull rod  70  forwardly so as to engage the integral lobe projections  613 ′ of the brake lever  60  within the limiting groove  524  in the inner wall surface of the front wall  521  of the housing  50 , thereby restoring the lever portion  62  of the brake lever  60  to its original position shown in FIG. 7, and thereby restoring the cart to its normal operating condition. 
     Referring to FIG. 9, when the lever portion  62  of the brake lever  60  is turned downwardly away from the handle  7  of the cart, the integral lobe projections  613 ′of the vertical plates  611  of the brake lever  60  maintain their engagement with the limiting groove  524  in the inner wall surface of the front wall  521  of the housing  50 , and the lever portion  62  rotates about the integral lobe projections  613 ′ such that the pivot pin  523  slides from the rear ends  6122 ′ to the front ends  6121 ′ (see FIG. 6) of the slide slots  612 ′ in the vertical plates  611  of the brake lever  60  so that the retaining portion  71  of the cable pull rod  70  separates from the retaining groove  632  in the positioning block  63  to move past the rearwardly extending protrusion  633  of the positioning block  63  so as to engage the abutment surface  631  of the positioning block  63 , thereby pulling and moving the rear end of the brake cable  6  rearwardly for braking the cart and thereby preventing further rotation of the brake lever  60  about the integral lobe projections  613 ′. The hand brake device  5  is positioned at a second braking position at this time. The lever portion  62  of the brake lever  60  can be turned upwardly toward the handle  7  only when an external force is applied to the lever portion  62 , thereby restoring the lever portion  62  to its original position shown in FIG. 7, and thereby restoring the cart to its normal operating condition. 
     From the above description of the preferred embodiment of the hand brake device  5  of the present invention, some of the advantages of the hand brake device  5  can be summarized as follows: 
     1. Since the brake lever  60  and the cable pull rod  70  are pivotally connected to the housing  10  by only one pivot pin  523 , elements of the hand brake device  5  are reduced. 
     2. When the brake lever  60  is turned from the position shown in FIG. 7 to that shown in FIG. 8, the rotational angle of the cable pull rod  70  is equal to that of the brake lever  60  such that the lower end  73  of the cable pull rod  70  and the brake cable  3  can be moved to a relatively large extent, thereby effectively executing a strong braking action on the cart. 
     3. Since the first braking position of the hand brake device  5  is frequently applied to the cart, and since the retaining portion  71  of the cable pull rod  70  engages fittingly the retaining groove  632  in the positioning block  63  of the brake lever  60  during rotation of the brake lever  60  from the position shown in FIG. 7 to that shown in FIG. 8, the retaining portion  71  and the retaining groove  632  in the positioning block  63  are less likely to quickly wear off. 
     While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.