Patent Publication Number: US-9417029-B1

Title: Arrow shaft pressing device for crossbow

Description:
BACKGROUND OF THE INVENTION 
     1. Fields of the Invention 
     The present invention relates to a crossbow, and more particularly, to an arrow shaft pressing device for a crossbow. 
     2. Descriptions of Related Art 
     The conventional crossbow is disclosed in  FIGS. 5 to 7 , and comprises a body  5  with a stock  62  connected thereto. The body  5  has a groove  63  defined in a top thereof. A shooting device  64  is connected to the body  6 . An aiming device  65  is connected to the shooting device  64  and located above the groove  63 . A pressing plate  66  is connected to the aiming device  65  and has a pressing end  661  which extends toward the groove  63 . 
     As shown in  FIG. 7 , when the string is pulled and engaged with the shooting device  64 , and an arrow shaft “A” is installed in the groove  63 , the pressing end  661  of the pressing plate  66  presses the shaft of the arrow “A” until the user operates the shooting device  64  to shoot the arrow “A”. However, the pressing plate  66  tends to reach its point of elastic fatigue after frequent uses. 
     The pressing plate  66  is fixed to the aiming device  65  by a bolt  662  which is connected to the aiming device  65  from the underside of the aiming device  65 . Because the space between the groove  63  and the aiming device  65  is so narrow that the screwdriver cannot be operated easily, so that the aiming device  65  has to be removed from the body  6  as shown in  FIG. 6 , such that the pressing plate  66  can be replaced. This is inconvenient for the users. 
     The present invention intends to provide an arrow shaft pressing device for a crossbow to eliminate the shortcomings mentioned above. 
     SUMMARY OF THE INVENTION 
     The present invention relates to an arrow shaft pressing device for a crossbow which has an aiming device connected to a body of the crossbow. The arrow shaft pressing device comprises a sleeve connected to one end of the aiming device and the sleeve has a passage defined axially therein. An aperture is defined through the lower end of the sleeve and co-axially communicates with the passage. A shoulder is formed at the connection portion between the passage and the aperture. A pressing member has a flange and a shank which extends from the underside of the flange. The pressing member is located in the passage of the sleeve and the distal end of the shank extends beyond the aperture. A restriction member is connected to the inside of the top end of the sleeve. A resilient member IS located in the passage and biased between the flange of the pressing member and the restriction member. The distal end of the shank of the pressing member resiliently presses the arrow shaft 
     Preferably, the cross sectional area of the flange of the pressing member is larger than that of the shank. 
     Preferably, the inside of the top end of the sleeve has inner threads, and the restriction member has outer threads which are threadedly connected to the inner threads of the sleeve. 
     Preferably, the distal end of the shank of the pressing member has a pressing portion which is a curved surface. 
     Preferably, the top end of the sleeve is connected to the aiming device by way of threading, snapping, engagement or locking. 
     Preferably, the sleeve has outer threads formed on the outside of the top end thereof. A stop extends radially from the outside of the sleeve and located below the outer threads of the sleeve. The outer threads of the sleeve are connected to a threaded hole of the aiming device, and the stop is in contact with the underside of the aiming device. 
     The primary object of the present invention is to provide an arrow shaft pressing device for a crossbow, and the pressing member is easily replaced without detaching the aiming device. 
     Another object of the present invention is to provide an arrow shaft pressing device for a crossbow, wherein the pressing member is biased by a resilient member which is able to be individually replaced without detaching the aiming device. 
     The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a crossbow with the arrow shaft pressing device of the present invention; 
         FIG. 2  is an exploded view of the arrow shaft pressing device of the present invention and a portion of the crossbow; 
         FIG. 3  is a cross sectional view of the arrow shaft pressing device of the present invention installed to the crossbow; 
         FIG. 4  is a cross sectional view of the arrow shaft pressing device of the present invention wherein the arrow shaft is pressed by the pressing member of the arrow shaft pressing device of the present invention; 
         FIG. 5  shows a portion of a conventional crossbow; 
         FIG. 6  is an exploded view to show the pressing plate and the aiming device of the conventional crossbow, and 
         FIG. 7  is a side view to show that the pressing plate presses the arrow shaft installed to the conventional crossbow. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 to 4 , a crossbow generally comprises a body  1  and a bow is connected to the front end of the body  1 . A string  11  is connected to two cam wheels on two limbs of the bow. A stock  12  is connected to the rear end of the body  1  and has a groove  13  defined in the top thereof. A shooting device  14  is connected to the body  1 . An aiming device  15  is connected to the shooting device  14  and located above the groove  13 . An arrow shaft “A” is installed in the groove  13  to be shot. 
     The arrow shaft pressing device of the present invention comprises a sleeve  2  which is connected to one end of the aiming device  15  of the body  1  of the crossbow. The sleeve  2  has a passage  21  defined axially therein, and an aperture  22  is defined through the lower end of the sleeve  2  and co-axially communicates with the passage  21 . The diameter of the aperture  22  is smaller than that of the passage  21  so as to form a shoulder  23  at the connection portion between the passage  21  and the aperture  22 . The sleeve  2  has outer threads  24  formed on the outside of the top end thereof. A stop  25  extends radially from the outside of the sleeve  2  and is located below the outer threads  24  of the sleeve  2 . The outer threads  24  of the sleeve  2  are connected to a threaded hole  151  defined through one end of the aiming device  15 , and the stop  25  is in contact with the underside of the aiming device  15 . The top end of the sleeve  2  can be connected to the aiming device  15  by way of threading, snapping, engagement or locking. The inside of the top end of the sleeve  2  has inner threads  211 . 
     A pressing member  3  has a flange  31  and a shank  32  which extends from the underside of the flange  31 . The cross sectional area of the flange  31  of the pressing member  3  is larger than that of the shank  32 . The pressing member  3  is located in the passage  21  of the sleeve  2  and the distal end of the shank  32  extends beyond the aperture  22 . The distal end of the shank  32  of the pressing member  3  has a pressing portion  33  which is a curved surface. 
     A restriction member  5  has outer threads  51  which are threadedly connected to the inner threads  211  of the sleeve  2 . A resilient member  4  is located in the passage  21  and biased between the flange  31  of the pressing member  3  and the restriction member  5 . The distal end of the shank  32  of the pressing member  3  extends beyond the aperture  22  of the sleeve  2  so as to resilient press the arrow shaft “A” in the groove  13  of the crossbow. 
     As shown in  FIG. 3 , the arrow shaft pressing device of the present invention is composed of the sleeve  2 , the pressing member  3 , the resilient member  4  and the restriction member  5 . The sleeve  2  is threadedly connected to the aiming device  15 , and the resilient member  4  is installed in the passage  21  of the sleeve  2 . When replacing the resilient member  4 , the sleeve  2  can be unthreaded from the threaded hole  151  of the aiming device  15 , and the restriction member  5  is removed from the sleeve  2  to replace the resilient member  4  individually while no other parts such as the aiming device  15  needs to be detached from the body  1 . 
     While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.