Abstract:
A compact manually operated air compression device for precompressed air guns has been disclosed, wherein two operating levers, positioned on opposite sides of a cylinder, are connected to a piston rod by means of connecting links. Lightweight connection of operating levers to the cylinder provided. Configuration of the device affords adjustment position of the piston in the cylinder.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a manually operated air compression device. 
     Known devices of this type generally are employed for pressurizing pre-compressed air guns, wherein at least one operating lever, swingably mounted with respect to the cylinder of compression assembly, connected to the piston via articulated linkage. Traditionally, some elements of this linkage occupy space, additional to the length of the cylinder, increasing length of the compression device. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a compact air compression device, wherein piston travel is maximal relatively to the device length. 
     According to the invention, an improved symmetrical lever assembly is employed with two operating levers pivoted on the cylinder of compression assembly. A first embodiment represents a high-pressure pump, which may be employed for pressurizing containers of so-called pre-charged air guns. Said pump also can be used outside of air guns class, where high air pressure is needed. A second embodiment of the invention is a pre-compressed air pistol, wherein one of operating levers is associated with a pistol frame. 
     Loading device, valve and trigger mechanism arrangements are out of the scope of this invention, and are not disclosed hereafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of the first embodiment of the invention in closed position; 
     FIG. 2 is a cross-section of the first embodiment in plane I—I of FIG. 1; 
     FIG. 3 is a side view of the first embodiment in open and mid-closed position; 
     FIGS. 4 and 6 are side views of the second embodiment of the invention in closed and open position respectively; 
     FIG. 5 is a cross-section of the second embodiment in plane II—II of FIG. 4; 
     FIG. 7 is a drawing of the connection between the piston rod and the anchor of the second embodiment; 
     FIG. 8 is an isometric view of the front portion of the cylinder of the second embodiment; and 
     FIG. 9 is an isometric view of the guide block of the second embodiment. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1,  2  and  3 , the first embodiment of the invention has a cylinder  11 , a lower end of which is inserted in a base block  14 . Movable in the cylinder  11  a piston  12  rigidly attached to a lower end of a piston rod  13 . Secured in an upper end of the cylinder  11  a guide block  15  serves as a guide for the piston rod  13 . An upper portion of the guide block  15  formed as a bracket for pivot connections  21  and  21   a  of operating levers  18  and  18   a  respectively. 
     An upper end of the piston rod  13  is provided with an anchor  17 . A link  16  is connected with one of its ends to the operating lever  18  by a pivot  20 . The other end of the link  16  is pivoted to the anchor  17  at  19 . A link  16   a  connects the lever  18   a  by a pivot  20   a  to the anchor  17  with a pivot  19   a.    
     Operating levers  18  and  18   a , links  16  and  16   a  preferably are U-shaped in cross-section. Links are wider than levers so that portion of the lever can come inside of the link when they fold along the cylinder. 
     Preferably, all construction is symmetrical with respect to the cylinder axis. 
     Shown additionally (FIG. 3) by phantom lines position of the device intermediate open and closed positions illustrates an advantage represented by the device to the user in overcoming hyperbolically increasing air pressure through a compression stroke. As seen, initial rotation of operating levers at approximately 60-degree angle causes excursion of the piston (piston rod) at ¾ of entire travel; last ¼ of the piston travel is performed by further rotation of operating levers at almost 90 degrees. This way forces exerted on the operating levers being low through the stroke. 
     Length relationships of elements in present embodiment are taken for instance. Practically, dimensioning of the device can be done only as based on or limited by following requirements: 
     air displacement, 
     compression rate or air pressure, 
     swinging angle of operating levers, 
     forces on operating levers, 
     total weight and 
     total length, 
     therefore cannot be disclosed here. 
     Present air compression device can be integrated in different types of pre-compressed air guns. In this case, parts of the device may be associated with parts of the gun and have different configuration. 
     An air pistol, wherein one of the operating levers associated with a pistol frame, represents the second embodiment of the invention. 
     Referring to FIGS. 4,  5  and  6 , the second embodiment has a cylinder  31  mounted on a pistol frame  38  by a pivot  36 . A breech block  34  is secured in a rear end of the cylinder  31 . A guide block  35  mounted in a front end of the cylinder  31 . Upper portions of said blocks  34  and  35  serve as brackets for a barrel  50 , and also for a rear sight  54  and a front sight  55  respectively. 
     An operating lever  39  swingably mounted on the cylinder  31  by a pivot  37 . A pair of links  41   r  and  41   l  is connected to the operating lever  39  with pivots  45   r  and  45   l . As seen, (FIG. 5) the operating lever  39  is formed with brackets  39   r  and  39   l  serving as supports for pivots  45   r  and  45   l . Pivoted on the pistol frame  38  at  46 , U-shapped in cross-section link  42  may have a slot  42   a  for a trigger guard in open position of the pistol. 
     A front end of a piston rod  33  is provided with an anchor  40  for pivot connections of the link  42  at  44  and pair of links  41   r  and  41   l  at  43 . 
     Thread connection between the anchor  40  and the piston rod  33  can be used for adjustment of the piston position in the cylinder. Referring to FIG. 7, the front end of the piston rod  33  is formed with a polygonal socket  33   s  so that piston rod  33  with the piston  32  can be rotated about their axis with a wrench. This feature allows loosening up length tolerances of parts of compression assembly and in certain limits adjustment of compression rate without disassembly of the device. 
     Referring to FIG. 8, the front end of the air cylinder  31  is formed with two flat mounting brackets  31   r  and  31   l  so that guide block  35  (FIG. 9) can be secured between said brackets with pivots  36  and  37 . In comparison with the first embodiment, this type of connection allows saving some space to increase piston travel for given length of the cylinder. The guide block  35  can be fabricated out of lightweight synthetic material, since it is not loaded by air pressure. 
     Although apparent to those skilled in art, some advantages of present air pistol should be mentioned here. 
     First, unusually big swinging angle of the operating lever helps to achieve high air pressure with low force even in very compact pistols. 
     Second, compressed air force is equally divided between two articulated linkages, positioned symmetrically with respect to the cylinder. This advantage positively affects pistol accuracy and gives a good opportunity in utilizing lightweight materials for lever assembly and pistol frame. 
     Third, great air displacement and high pressure afford utilizing big caliber projectiles with sufficient velocity.