Abstract:
An electromotive stapler according is provided with a paper holder, which is linked with a striking block, to press the neighborhood of the place where the staple is driven, whereby binding of many sheets of paper is possible without consuming much power of the motor, the pressing force of the paper holder being obtained by motion of push rod to press the paper holder, and the force of push rod necessary therefor being obtained by a coil spring compressed by the motion of the striking block.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a stapler which binds together papers with a staple, and more particularly to a stapler which is driven by an electric motor. 
     In a conventional electromotive stapler, in order to minimize the load of the motor, a paper holder is not provided. The function of a paper holder is to hold the papers to be bound tightly around the point at which the staple is struck. Without the holder, however, the staple is inclined with respect to the striking block due to paper displacement. This results in binding failure, especially when the papers are thick. To prevent such failure, the striking force of the striking block and, therefore, the power of the motor is increased. 
     SUMMARY OF THE INVENTION 
     An electromotive stapler is provided with a paper holder to press down the area surrounding the point at which the staple is struck. In this manner, more sheets of paper are capable of being bound without increasing the power of the motor. The pressing power of the paper holder is generated by the pushing motion of a push rod which is generated by a coil spring compressed by the motion of the striking block. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view of an electromotive stapler according to an exemplary embodiment of the present invention. 
     FIG. 2 is a plan view of an electromotive stapler with the cover removed according to an exemplary embodiment of the present invention. 
     FIG. 3 (a) is a plan view of an insertion case according to an exemplary embodiment of the present invention. 
     FIG. 3 (b) is a front view of the insertion case which is illustrated by FIG. 3(a). 
     FIG. 4(a) is a plan view of a staple case according to an exemplary embodiment of the present invention. 
     FIG. 4(b) is a front view of the staple case. 
     FIG. 5(a) is a side view of a staple case and an insertion case which has been assembled. 
     FIG. 5(b) is a plan view of the assembled staple case and insertion case which is illustrated in FIG. 5 (a) . 
     FIG. 6 is a perspective view of the electromotive stapler according to an exemplary embodiment of the present invention. 
     FIG. 7 is a perspective view of a striking block according to an exemplary embodiment of the present invention. 
     FIG. 8(a) and 8(b) show a push rod fixed onto a striking block. 
     FIG. 9 shows a push rod pushing a paper holder. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An example of an electromotive stapler according to the present invention is explained below with reference to the drawings. 
     FIG. 1, FIG. 2 and FIG. 6 show an example of a stapler according to the present invention. The driving torque of a motor 1 is transmitted to a driving gear 2 via intermediate gears 22 and 22&#39;. The driving gear 2 is provided on its side with a boss 3 having a rotation-free ring 3&#39; on the periphery. Boss 3 is inserted into a slide slot 4&#39; of a coupling rod 4. The coupling rod 4 is fastened to the main frame by a fulcrum shaft 5. A striking block 9 is attached to the end of the coupling rod 4 through a hole 6, to move reciprocally in the collar of the main frame by rotation of motor 1. 
     FIG. 7 is a perspective view of the striking block 9, which has projections9&#39; on the front surface, and a staple striking blade 30 on the bottom surface. The striking block 9 is further, as shown in FIG. 8, provided with a push rod 7 by the projections 9&#39;. As shown in FIG. 8(a) and FIG. 8(b), the striking block 9 is provided with a projections 9&#39; having a pushrod case 29 for the push rod 7 which is pierced by a pin 6&#39; and surrounded by a coil spring. 
     The push rod 7 being held on the striking block 9 as the pin 6&#39; and a push rod case 29 press the projections 9&#39; therebetween by the force of a spring11, moves downwards, as the striking block 9 moves downwards, to touch a paper holder 8. As shown in FIG. 9, 9 moves downwards, to touch a paper holder 8. As shown in FIG. 9, while the striking block 9 moves down, the push rod 7 remains at the initial place, and the spring 11 is further compressed, so that, the push rod 7 presses the papers through the paper holder 8. That is, the pressure with which the push rod 7 presses the paper holder 8 is obtained by the compression of the coil spring 11. A staple bending plate 10 is provided with a staple bending groove 10a for bending the end of a staple. 
     In FIG. 1 and FIG. 3, an insertion case 12 is held by the main frame so as to be rotation-free around a fulcrum 14. As shown in FIG. 1 and FIGS. 4(a)and 4(b), a staple case 13 is equipped with a paper holder 8. The staple case 13 is inserted slidingly into the insertion case 12, and is supplied with staples while the staple case 13 is drawn from the insertion case 12.In FIGS. 5(a) and 5(b) is shown the staple case 13 at the innermost part ofthe insertion case 12. The B surface (FIG. 4(b)) of the staple case 13 touches on the A surface (FIG. 3a) of the insertion case 12 tightly. Binding of papers is carried out under this condition. A pin 15 coupling the staple case 13 and the insertion case 12 is given a force of upward direction by an end of the spring 28 (FIG. 1), and this upward-directed force works, via D part (FIG. 4) of the staple case 13, to the direction of the arrow i.e. to the direction as to increase the contacting pressure between both parts. 
     In FIG. 5 (b), the narrow space t between both parts is called a stapling gap. The staple striking blade 30 of the striking block 9 moves through inthis stapling gap to strike the staples into the papers. 
     As shown in FIG. 5 (b) , one of the sides of the stapling gap (right side) is made by a part of the insertion case 12, the other side of the staplinggap (left side) is made by a part of the staple case 13. 
     The width t of the stapling gap is precisely determined by precisely manufacturing the distance A&#39; and B&#39;. A&#39; and B&#39; are the distance between the tightly contacted point of both above mentioned parts and each side ofthe stapling gap. 
     Returning to FIG. 1, the coupling of the staple case 13 and the insertion case 12 is released by pushing a release stick 16 to move the pin 15 downwards. The spring 28, as described above, pushes the pin 15 upward by the one end and pushes the staple case 13 to the left side by the other end, and, accordingly, the staple case 13 jumps out to the left as the coupling of the both parts is released, to be easily supplied with staples. The electromotive stapler is further provided with a switch lever17, a printed circuit board 18 involving a control circuit to drive the motor 1, a cover 19, base plate 20, a battery cover 21 and batteries 23, 24, 25, 26. The operation of the stapler is explained below. 
     Initially, both the striking block 9 and the push rod 7 are at the top deadcenter. When the papers to be bound are pushed in, pressing the switch lever 17, the motor 1 rotates. The rotation of the motor 1 is transmitted to the driving gear 2 via the intermediate gear 22 and 22&#39;, the coupling rod 4 is driven by the boss 3, striking block 9 and push rod 7 moves down from the top dead center, and the push rod 7 pushes the paper holder to press the papers to be bound. The striking block 9 further goes down to push down the staple kept between the insertion case 12 and the staple case 13, so that, the end of the staple pierces through the papers to be bound and is bent by the staple bending groove 10a of the staple bending plate 10 to bind the papers. The motor 1, after rotating somewhat further,stops when the striking block 9 and push rod 7 are returned to the top deadcenter to open a microswitch (not shown).