Abstract:
An assisting ejection device is provided for assisting ejection a hatch of a hatchback. The assisting ejection device includes spring-biased rod to act on the hatch. The spring is in a compressed condition when the hatch is closed so that when the hatch is released from the closed condition, the spring that is allowed to extend provides a springing force to help pneumatic cylinders that are originally provided to automatically lift the hatch to eject the hatch toward a flip-up position. The springing force effectively reduces the load applied to the pneumatic cylinders in opening the hatch so as to extend the service life of the pneumatic cylinders.

Description:
BACKGROUND OF THE INVENTION 
     (a) Technical Field of the Invention 
     The present invention relates generally to the field of automobile, and in particular a hatchback having an assisting ejection device for the hatch to facilitates opening operation of the hatch and extension of the service life of the hatch mechanism. 
     (b) Description of the Prior Art 
     A hatchback is an automobile having a cargo space integrated with a passenger cabin and is accessed through a hatch or a flip-up window. The cargo space of the hatchback is different from that of a truck and must be accessed by flipping upward the hatch that is hinged to a frame of a tail gate of the automobile. 
       FIGS. 1 and 2  of the attached drawings illustrate a hatchback having a hatch, designated at  1 , having an upper edge pivotally connected to a tail gate frame  11  of the hatchback by hinges  12 . Two pneumatic cylinders  13  are arranged on opposite sides of the hatch  1  and have opposite ends pivoted to opposing portions of the hatch  1  and the rail gate frame  11 . A lock  14  is arranged at a lower edge of the hatch  1  and is releasably engageable with a hook  15  provided on the rail gate frame  11  to selectively secure the hatch  1  to the tail gate frame  11 . The lock  14  can be disengaged from the hook  15  to release the hatch  1  and the pneumatic cylinders  13  eject and force the hatch  1  away from the frame  11  to thereby flip the hatch upward. Dampers  16  are often provided between the hatch  1  and the frame  11 . The dampers  16  are made of resilient material or having a resilient function. The steel plate  17  that constitutes the frame  11  is machined to form slots  18  in which the dampers  16  are received and retained. The dampers  16  serve to absorb the shock and impact induced when the hatch  1  is brought into contact with the frame  11  in closing the hatch  1 . 
     The conventional arrangement of the hatch, however, suffers insufficient driving force provided by the pneumatic cylinders  13  to flip the hatch  1  up when the automobile has been used for a long time and parts of the automobile are thus subject to aging problems. The aging of the pneumatic cylinders  13  reduce the driving force acting upon the hatch  1  so that when the lock  14  is released, the hatch  1  cannot automatically move away from the frame  11  and manually flipping the hatch  1  has to be carried out. 
     Although the pneumatic cylinders  13 , as being regular mechanical parts, are subject to limitation of service life, which is determined not only by the nature of the pneumatic cylinders  13  themselves, but also the operation cycle thereof. Excessive numbers and load of opening/closing the hatch  1  often leads to reduced life span of the hatch  1 . Thus, the present invention is aimed to extend the service life of the hatch by reducing the load applied to the pneumatic cylinders. 
     SUMMARY OF THE INVENTION 
     The primary purpose of the present invention is to provide an assisting ejection device that provides additional ejection force that facilitates pneumatic cylinders to open a hatch of a hatchback so as to overcome the conventional drawbacks of insufficiency of hatch opening force from the pneumatic cylinders. 
     To achieve the above described goal of the present invention, an assisting ejection device is provided between a hatch and a tail gate frame of a hatchback. The assisting ejection device comprises a base, a rod, a spring and an enclosure. The base comprises tenon members that are resiliently fit into a slot defined in the hatchback to secure the assisting ejection device to the hatchback. The rod is fit through the spring and is movably coupled to the base. An end of the rod forms a retention section that extends beyond the base and engages a fastener to retain the rod to the base and to define a movement stroke of the rod with respect to the base. An opposite end of the rod, being biased by the spring, acts upon the hatch to help opening the hatch by the biasing force of the spring. The enclosure is in the form of a bellow having an open end fit over and enclosing the rod and the spring and attached to the base. 
     The foregoing object and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts. 
     Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be apparent to those skilled in the art by reading the following description of prefered embodiments thereof, with reference to the attached drawings, wherein: 
         FIG. 1  is a perspective view of a conventional hatchback having a hatch in a lifted condition; 
         FIG. 2  is a side elevational view, partially broken, of the hatch of the hatchback; 
         FIG. 3  is an exploded view of an assisting ejection device constructed in accordance with the present invention; 
         FIG. 4  is a cross-sectional view of the assisting ejection device of the present invention in an assembled form; 
         FIG. 5  is a cross-sectional view illustrating the assisting ejection device of the present invention installed on a hatchback; 
         FIGS. 6 and 7  are cross-sectional views of a rear portion of the hatchback on which the assisting ejection device of the present invention is installed to respectively illustrate opening and closed conditions of the hatch for demonstrating the operation of the assisting ejection device of the present invention; 
         FIG. 8  is a cross-sectional view illustrating an assisting ejection device constructed in accordance with another embodiment of the present invention; 
         FIG. 9  is a perspective view illustrating an assisting ejection device constructed in accordance with a further embodiment of the present invention; and 
         FIG. 10  is a perspective view illustrating an assisting ejection device constructed in accordance with yet a further embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following descriptions are of exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims. 
     With reference to the drawings and in particular to  FIGS. 3 and 4 , an assisting ejection device constructed in accordance with the present invention, generally designated with reference numeral  2  is mounted to a tail gate of a hatchback to assist ejection of the hatch from the tail gate in opening the hatch. The assisting ejection device  2  in accordance with the present invention comprises a base  21 , a rod  22 , a spring  23  and an enclosure  24 . 
     The base  21  has a top face on which an annular slot  211  is formed. The base  21  also defines a bore  212  at a center thereof. The base  21  also has a circumferential side face along which a circumferential groove  213  is formed. The base  21  has a bottom face, opposite to the top face, from which a plurality of tenon members  214  extends axially and arranged around an outer circumference of the bore  212 . The tenon members  214  are configured to form recesses  215  located at the connection between the tenon members  214  and the bottom face of the base  21  and aligned with each other and extending in a circumferential direction. 
     The rod  22  has an upper end forming a cap  221  delimiting an annular slot around the rod  22  and a lower end forming a retention section  222 , which in the embodiment illustrated comprises a circumferential groove. 
     The spring  23 , which is a helical spring in the embodiment illustrated, has an outer diameter sized to substantially fit into the annual slot  211  of the base  21  and the annular slot delimited around the rod  22  by the cap  221  so as to retain the spring  23  between the cap  221  of the rod  22  and the top face of the base  21 . 
     The enclosure  23  is made of a soft and resilient material in the form of a bellow having an open end and an opposite closed end. The open end of the bellow enclosure  23  forms a circumferential flange  241  that projects inward. 
     To assemble the assisting ejection device  2  of the present invention, the rod  22  is put through the spring  23  to be encompassed by the spring  23  and an end of the spring  23  is fit into the cap  221  of the rod  22 . The lower end of the rod  22  is then inserted through the bore  212  of the base  21  so that the opposite end of the spring  23  is received into the annular slot  211  on the top face of the base  21 . The rod  22  is forcibly pushed into the bore  212  of the base  21  to partially compress the spring  23 , causing the lower end of the rod  22  to extend beyond the bottom face of the base  21  and the retention section  222  exposed outside the tenon members  214  that are provided on the bottom face of the base  21 . A clip A is then fit into and engages with the circumferential groove of the retention section  222 . The clip A is allowed to abut against free ends of the tenon members  214  when compressing force of the spring  23  is released. This secures the spring  23  to the base  21 . Thereafter, the open end of the enclosure  24  is fit downward over, in sequence, the cap  221  of the rod  22  and the spring  23  to allow flange  241  of the enclosure  24  to engage the circumferential groove  213  of the base  21  thereby attaching the enclosure  24  to the base  21  and completing the assembling of the assisting ejection device  2 . 
     Referring to  FIG. 5 , to install the assisting ejection device  2  to the hatch  1  or the tail gate frame  11  of a hatchback, an existing damper  16  that is originally mounted to the automobile is removed to expose the damper-mounting slot  18  that is defined in the steel plate  17  of the automobile. The tenon members  214  are put in alignment with the slot  18  and is then forced into the slot  18  by means of deformation facilitated by resilience thereof until the circumferentially extending recesses  215  of the tenon members  214  engage a circumference of the slot  18  to thereby retain the assisting ejection device  2  to the slot  18 . The assisting ejection device  2  is thus installed on the hatch  1  or the tail gate frame  11  of the hatchback. 
     Also referring to  FIGS. 6 and 7 , when the hatch  1  is closed on the tail gate frame  11 , the lock  14  of the hatch  1  engages the hook  15  of the tail gate frame  11  to secure the hatch  1  in the closed position. In the closed condition, the assisting ejection device  2  is pressed by the hatch  1  to move the rod  22  further into the bore  212  of the base  21  so that the spring  23  is compressed and potential energy is stored in the compressed spring  23 . 
     When the lock  14  is unlocked and disengages from the hook  15  of the tail gate frame  11 , the pneumatic cylinders  13  that are originally provided between the hatch  1  and the tail gate frame  11  gradually drives the hatch  1  away from the tail gate frame  11  and at the same time, the compressed spring  23  of the assisting ejection device  2  of the present invention is no longer constrained and the potential energy stored therein is immediately released and a springing force is induced to provide additional force for ejecting the hatch  1  away from the tail gate frame  11 . The rod  22  is now allowed to move outward with the expansion of the spring  23  and the outward movement of the rod  22  is ultimately stopped by the clip A that is brought into contact with the tenon members  214  of the base  21  by the outward movement of the rod  22 . In this open condition, the assisting ejection device  2  of the present invention is again ready for the next operation. 
     Also referring to  FIG. 8 , if necessary, a spring washer  25  is fit over the tenon members  214  and received in the circumferentially extending recesses  215  so that when the assisting ejection device  2  of the present invention is installed to the steel plate  17  of a body of the hatchback, the spring washer  25  is interposed between the bottom face of the base  21  and the steel plate  17  to effect tightness, sound absorption and shock reduction between the assisting ejection device  2  and the steel plate  17  of the automobile body. 
     Referring to  FIG. 9 , which shows a modification of the assisting ejection device  2  of the present invention, the retention section  222  of the modified embodiment of the assisting ejection device  2  comprises a diametrically extending through hole, rather than a circumferential groove, and a cotter pin B can received through the hole to abut against the tenon members  214  of the base  21  for retention purposes. Alternatively, another modification of the assisting ejection device  2  of the present invention is illustrated in  FIG. 10 , wherein the retention section  222  of the rod  22  is formed with thread, which is engageable with a nut C that, similarly, abuts against the tenon members  214  of the base  21  for retention purposes. 
     To summarize, the assisting ejection device  2  of the present invention can be selectively installed in either the hatch or the tail gate frame of a hatchback and the springing force of the spring  23  of the assisting ejection device  2 , when released from a compressed condition, helps the pneumatic cylinders to eject the hatch from the tail gate frame of the hatchback. Further, with the assistance force provided by the spring  23  of the assisting ejection device  2  of the present invention, the load of opening the hatch applied to the pneumatic cylinders can be reduced. Thus, the service life of the pneumatic cylinders  13  can be extended. 
     Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims. 
     It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. 
     While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.