Abstract:
A cabinet door buffer bar includes a hollow tube, a shaft, an elastic element and a sliding member. The sliding member and the inner wall of the hollow tube form different intervals there between so that a resilient member mounted thereon receives varying constraints and generates different buffer forces in different moving directions thereby provides the cabinet door a required buffer force to avoid generating annoying noise and incurring damages during closing of the cabinet door.

Description:
This nonprovisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 92113592 filed in Taiwan on May 20, 2003, which is herein incorporated by reference. 
   FIELD OF THE INVENTION 
   The present invention relates to a cabinet door buffer bar for controlling moving speed of a moving mechanism and serving as a damping buffer and particularly to a buffer bar to prevent a cabinet door from generating annoying noise and being damaged while closing. 
   BACKGROUND OF THE INVENTION 
   A buffer bar generally is used to control the speed of door opening/closing and a moving mechanism. The most common application is a door check for automatically and slowly closing the door without generating a big noise or damaging the door or door frame. It also may be adopted on other movable mechanisms that have a returning force and also need a resistant force against the movement to serve as a damping buffer. In general, the buffer resistant force generated by the buffer bar has two types of sources: a pneumatic type and an oil pressure type, or the so-called air pressure bar and oil pressure bar. 
   The conventional buffer bar has a big drawback, i.e. oil leakage or air leakage. This problem could cause dysfunction of the buffer bar. When used on cabinet windows or doors, in addition to the aforesaid problem, the factors of outside appealing and ornamental effect also have to be considered. The huge noise of the pneumatic bar and oil leakage of the oil pressure bar are problems not acceptable for general cabinets. While the huge noise of the pneumatic bar makes the cabinet not appealing, oil leakage of the oil pressure bar tends to smear the cabinet and articles held in the cabinet. 
   Hence the cabinet generally is not equipped with the buffer bar. As a result, a big noise is generated when the cabinet door is closed, and the cabinet door or cabinet is easily damaged. Because of the appealing consideration, someone introduced a buffer bar in a conventional hinge. However, while the hinge thus made has a buffer function, it is still not effective. And the problems mentioned above still exist. 
   SUMMARY OF THE INVENTION 
   Therefore the present invention aims to resolve the aforesaid problems and provide a cabinet door buffer bar that has a required buffer force to prevent the cabinet door from generating annoying noise and being damaged while closing. 
   The cabinet door buffer bar according to the invention includes a hollow tube, a shaft and an elastic element. The hollow tube is to house the shaft and enables the shaft to be movable therein. The elastic element provides a returning force for the relative movement. The buffer resistant force is generated by the interference between a resilient member located outside the shaft and the inner wall surface of the hollow tube. 
   In one aspect, the front end of the shaft and the inner wall of the hollow tube have a gap, which varies in the axial direction of the shaft. Hence the resilient member on the front end of the shaft can generate a different degree of friction when it slides in different directions, thereby it creates a buffer effect desired. 
   In another aspect, a coupling ring made from a buffer material is provided that has one end fastened to the shaft and another end coupled with a sliding member. The sliding member is made of a hard material so that when the shaft is moved relative to the hollow tube, the sliding member is slid through the coupling ring, and the coupling ring is extended without generating friction with the inner wall surface of the hollow tube. When the shaft is moved inwards, the coupling ring compresses the sliding member and results in deformation and radial expansion of the coupling ring. As a result, interference occurs between the coupling ring and the inner wall surface of the hollow tube, to provide a buffer resistant force. 
   Another object of the invention is to provide a buffer bar that has an adjustable buffer resistant force. 
   The damping unit includes an adjustment element for adjusting the moving interval of the sliding member. Thus the movable range of the sliding member is altered when the buffer bar returns to enable the coupling ring to generate a different degree of expansion, thereby changing the buffer resistant force of the buffer bar. 
   The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
       FIGS. 1A and 1B  are schematic views of the invention in use conditions. 
       FIG. 2  is a schematic view of a first embodiment of the invention. 
       FIGS. 3A and 3B  are schematic views of the first embodiment in operating conditions. 
       FIG. 4A  is a schematic view of a second embodiment of the invention. 
       FIG. 4B  is a schematic view of a third embodiment of the invention. 
       FIGS. 5A and 5B  are schematic views of the third embodiment in operating conditions. 
       FIG. 6  is a schematic view of a third embodiment of the invention including an adjustment mechanism. 
       FIG. 7  is a schematic view of a fourth embodiment of the invention. 
       FIG. 8  is a schematic view of the invention in use. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The cabinet door buffer bar  1  according to the invention aims to be installed on a cabinet wall  72  of a cabinet door  71  (referring to  FIGS. 1A and 1B ) to provide a buffer when the cabinet door  71  is closed (referring to  FIG. 1A ). When the cabinet door is closed in normal conditions, it provides an elastic force smaller than the closing force of the cabinet door  71  (referring to  FIG. 1B ), to maintain the cabinet door in the closed condition. 
   Refer to  FIG. 2  for a first embodiment of the invention. It includes a hollow tube  10 , a shaft  20 , an elastic element  30  (mostly a spring, the drawing shows merely an example) and a resilient member  221 . The hollow tube  10  has a housing compartment  11  to house the shaft  20 . The shaft  20  has a tongue  21  located at the bottom end and is extended outside. The elastic element  30  is housed in the housing compartment  11 , pressing the bottom of the shaft  20  to provide a returning elastic force. The hollow tube  10  has a bottom end to allow the tongue  21  to be extended and exposed without the entire shaft  20  escaping. The shaft  20  has a front end forming a housing section  22 , which has a top end close to the inner wall of the hollow tube  10  to form different gaps G 1  and G 2  in the axial direction of the shaft  20 . The resilient member  221  is located on the housing section abutting the gaps and is in contact with the inner wall of the hollow tube  10  in normal condition, and is made from a resilient and cushion material such as rubber, which is deformable. 
   When in use, and the cabinet door  71  is opened (referring to  FIG. 1A ), the shaft  20  is pushed by the elastic element  30  and the tongue  21  is extended and exposed outside the hollow tube  10  (referring to  FIG. 3B ). When the shaft  20  is moved outwards, a friction force occurs between the resilient member  221  and the inner wall of the hollow tube  10 . As the gap G 2  between the housing section  22  and the inner wall of the hollow tube  10  is greater, the resilient member  221  is deformed with relatively less constraint, and the friction force is smaller. Hence the tongue  21  reaches a desired position quickly. 
   On the other hand, when the cabinet door  71  is closed (referring to  FIG. 1B ), the tongue  21  is compressed by the cabinet door  71  and moved inwards (referring to  FIG. 3A ). The contact between the tongue  21  and the cabinet door  71  generates a friction. Hence the distal end of the tongue  21  is formed with a curved shape to avoid damaging the cabinet door  71 . Meanwhile, a friction occurs between the resilient member  221  and the inner wall of the hollow tube  10 . As the gap G 1  between the housing section  22  and the inner wall of the hollow tube  10  is smaller, the space for deformation of the resilient member  221  is limited. Hence the friction force is much greater, thus a buffer effect is achieved. Of course, the forces of the elastic element  30  and the resilient member  221  have to be smaller than the force of closing the cabinet door  71 , to allow the cabinet door  71  to be closed as desired. 
   Refer to  FIG. 4A  for a second embodiment of the invention. A sliding member  23  is located on the outer side of the shaft  20 . The sliding member  23  also forms different gaps with the inner wall of the hollow tube as the previous embodiment does. It also is coupled with the resilient member  221 . And it is connected to the shaft  20  through a flexible element  24  which may be made from plastics, steel wire, or the like so that the shaft  20  is connected to the sliding member  23  without restricting its motion. Refer to  FIG. 4B  for a third embodiment. In this embodiment, the flexible element  24  is replaced by a coupling ring  25  made from a buffer material (such as rubber). 
   The coupling ring  25  has one end fastened to the shaft  20  and the other end connected to a sliding member  23 . When the cabinet door  71  is opened as shown in  FIG. 1A , it is pushed by the elastic element  30 , and the tongue  21  is exposed outside the hollow tube  10 , and the coupling ring  25  is driven to move the sliding member  23  (referring to  FIG. 5B ). As the sliding member  23  is rigid and only connected to the coupling ring  25 , when the coupling ring  25  moves the sliding member  23 , the coupling ring  25  is extended and deformed and its outer diameter shrinks slightly, therefore the friction between the coupling ring and the inner wall of the hollow tube  10  decreases. Thus the tongue  21  may return easier. In order to protect the coupling ring  25  from being damaged because of over extension, a hard circular ring  27  may be fastened to the top end of the shaft  20  to limit the maximum extension length of the coupling ring  25 . When the cabinet door  71  is closed as shown in  FIG. 1B , the tongue  21  will be pushed and the shaft  20  will slide inwards in the hollow tube  10 . The sliding member  23  remains stationary, due to its rigidity when the shaft  20  is just moved inwards. The coupling ring  25  is pushed by the shaft  20  and the front side is stopped by the sliding member  23 , thus the coupling ring  25  is compressed and deformed to slightly expand its outer diameter (referring to  FIG. 5A ), and an interference occurs in the interior of the hollow tube  10  to generate a required buffer resistant force. In this embodiment, both the resilient member  221  and the coupling ring  25  provide buffer forces. The shaft  20  has a neck section  222  to couple with an adjustment member  26  to adjust the sliding distance of the sliding member  23  as shown in  FIG. 6  so that the deformation of the coupling ring  25  may be altered to adjust the buffer force. 
   Refer to  FIG. 7  for a fourth embodiment of the invention. The resilient member  221  is dispensed with. The buffer force is provided by the coupling ring  25  only. Of course an adjustment mechanism may also be provided. On the other hand, also see  FIG. 2 , the gaps G 1  and G 2  on two sides may also be altered to adjust the buffer force generated. In applications, besides being fastened directly to the cabinet wall  72 , the invention may also be mounted on a bracket  42 (not shown in  FIG. 7 ). Referring to  FIG. 8 , a bracket  42  is mounted on a hinge seat  73 , which has an annular member  41  on one side. The annular ring  41  is hollow to house and fasten a cabinet door buffer bar  1 . The bracket  42  has a hook section  421  to couple on the hinge seat  73 . Then screws  51  through fastening holes  422  fasten the bracket. Such a design is more convenient. 
   While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments, which do not depart from the spirit and scope of the invention.