Power stapler

A power stapler including a cover shell, a base, a frame, a circuit board assembly, an electromagnetic valve, a magazine and tie plate assembly, an anvil, a micro-switch, a presser case assembly, a staple magazine constraint control device, an adjusting rod, and a linkage, wherein the valve block of the electromagnetic valve is controlled by the circuit board to drive the linkage causing the presser case assembly reciprocated to achieve a striking in driving a staple through the sheets of paper to be fastened; the adjusting rod is turned to move the circuit board assembly in changing the position of the micro-switch so that the binding position is adjusted.

BACKGROUND AND SUMMARY OF THE INVENTION 
The present invention relates to staplers, and more particularly to a power 
stapler for bookbinding. 
FIG. 1 shows a power stapler according to the prior art which comprises a 
motor, a transmission gear coupled to the motor, a driven gear wheel 
meshed with the transmission gear and having an eccentric rod, a forked 
link, a striking plate pulled by a spring and stopped by the forked link, 
and an anvil. When the motor is turned on, the driven gear wheel is turned 
by the transmission gear to move the forked link by the eccentric rod 
thereof, causing the forked front end of the forked link released from the 
striking plate, and therefore the spring immediately pulls down the 
striking plate causing a staple driven through the sheets of paper being 
placed on the anvil. This structure of Dower stapler is not suitable for 
fastening a thick stack of paper because the striking plate is not forced 
downward to strike the staple by a high pressure from the top but simply 
pulled down by the spring. When the striking plate is pulled to driven a 
staple through a thick stack of paper, the driven gear wheel or its 
eccentric rod or the transmission gear may be damaged easily. Another 
drawback of this structure of power stapler is that the binding position 
is not adjustable. Still another drawback of this strucutre of power 
stapler is its complicated structure. 
The present invention has been accomplished to provide a power stapler 
which eliminates the aforesaid drawbacks. According to one aspect of the 
present invention, the power stapler including a cover shell, a base, a 
frame, a circuit board assembly, an electromagnetic valve, a magazine and 
time plate assembly, an anvil, a micro-switch, a presser case assembly, a 
staple magazine constraint control device, an adjusting rod, and a 
linkage, wherein the valve block of the electromagnetic valve is 
controlled by the circuit board to drive the linkage causing the presser 
case assembly reciprocated to achieve a striking in driving a staple 
through the sheets of paper to be fastened. 
According to another aspect of the present invention, the adjsuting rod can 
be turned in either direction to move the circuit board assembly in 
changing the position of the micro-switch so that the binding position is 
adjusted. 
According to still another aspect of the present invention, the staple 
magazine is automatically pushed out of the magazine seat by a spring for 
loading staples when the link is rotated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 2 through 7, the power stapler of the present invention 
comprises mainly a cover shell (not shown), a base 101, a frame 2 mounted 
on the base 101, a circuit board assembly 4 mounted on the frame 2 at the 
bottom near the front end, an electromagnetic valve 3 mounted on the frame 
2 at the bottom near the rear end, a magazine and tie plate assembly 6 
mounted on the frame 2 at the top near the front end, an anvil 21 mounted 
on the frame 2 at the top below the front end of the magazine and tie 
plate assembly 6, a micro-switch 5 mounted on the circuit board assembly 4 
and having a switching lever 51 projecting out of the top surface of the 
frame 2 for triggering by the sheets of paper 10 to be fastened, a presser 
case assembly 7 disposed above the magazine and tie plate assembly 6 and 
operated to move the striking plate 71 thereof into the magazine and tie 
plate assembly 6 to achieve a binding action, a staple magazine constraint 
control device 8 for pushing the staple magazine 61 of the magazine and 
tie plate assembly 6 into the binding position, an adjusting rod 9 for 
adjusting the position of the circuit board assembly 4, and a linkage 1. 
The frame 2 comprises a front support 22, a first pivot axle 24 
transversely supported on the front support 22 pivotally coupled with the 
two opposite middle portions 11 of the linkage 1, a rear support 23, a 
second pivot axle 25 transversely supported on the rear support 23 and 
pivotally coupled with the front end 72 of the presser case assembly 7 and 
the channel plate 811 of the magazine constraint plate 81 of the staple 
magazine constraint control device 8 and the coupling portion 621 of the 
magazine seat 62 of the magazine and tie plate assembly 6, a slot 26 for 
passing the two opposite rear ends 12 of the linkage 1, a hook 27 at the 
top for fastening one end of the spring 83 of the staple magazine 
contraint control device 8, and a sliding way 28 at the bottom. 
The electromagnetic valve 3 comprises a valve block 31 connected to the two 
opposite bottom ends 12 of the linkage 1 and controlled by the circuit 
board assembly 4 to move back and forth. When the valve block 31 is 
reciprocated, the linkage 1 is oscillated on the first pivot axle 24. 
The circuit board assembly 4 comprises a box 41 and a circuit board 
received inside the box 41. The box 41 has two opposite side rails 411 
made to slide in the sliding way 28 (see FIGS. 5 and 6). One of the side 
rails 411 has a toothed bottom wall 4111 meshed with a driving gear 91 on 
the adjusting rod 9. Therefore, the position of the circuit board assembly 
4 in the sliding way 28 can be changed by turning the adjusting rod 9 in 
either direction. 
The micro-switch 5 is installed in the circuit board of the circuit board 
assembly 4 with its switching lever 51 extended out of the box 41 and 
projecting over the frame 2. 
The magazine and tie plate assembly 6 comprises a magazine seat 62 having a 
coupling portion 621 coupled to the channel plate 811 of the magazine stop 
plate 81 of the staple magazine constraint control device 8 by the second 
pivot axle 25 on the rear support 23 of the frame 2 and a bottom wall 620 
supported on a spring plate 29 above the frame 2 in an oblique position 
sloping upwards forwards, a spring plate 622 fixed to the rear end of the 
magazine seat 62, a staple magazine 61 made to slide on the magazine seat 
62 and having a rear end 611 stopped at the spring plate 622, a projecting 
block 612 raised from the rear end 611 of the staple magazine 61 and 
constrained by the bottom end 812 of the magazine constraint plate 81 of 
the staple magazine constraint control device 8. As shown in FIG. 4, the 
projecting block 612 is constrained by the magazine contraint plate 81, 
therefore the staple magazine 61 is prohibited from being pushed forward 
by the spring plate 622. 
The presser case assembly 7 has a rear end pivotally connected to the 
second pivot axle 25 and a front end 72 spaced above the magazine and tie 
plate assembly 6 and linked to the front cross rod 13 of the linkage 1. 
The presser case assembly 7 further comprises a first hook 73 and a second 
hook 76 at the top, a spring 74 having one end fastened to the first hook 
73 and an opposite end inserted through a hole 75 on the casing of the 
presser case assembly 7 and connected to a hook 625 on the magazine seat 
62 (see FIG. 3). 
The staple magazine constraint control device 8 comprises a magazine 
constraint plate 81, a link 82, and two spirngs 83 and 84. The magazine 
constraint plate 81 comprises a channel plate 811 at the top pivotally 
coupled to the coupling portion 621 of the magazine seat 62 by the second 
pivot axle 25, a bottom end 812 stopped against the projecting block 612 
of the staple magazine 61 at the front. The spring 84 has one end fastened 
to the top end 813 of the magazine constraint plate 81, and an opposite 
end fastened to the second hook 76 of the presser case assembly 7. The 
link 82 is coupled to the frame 2 at the back, having a driving plate 821 
at the front. By turning the link 82, the magazine constraint plate 81 is 
moved away from the projecting block 612 of the staple magazine 61 by the 
driving plate 821, thereby causing the staple magazine 61 pushed forward 
by the spring plate 622 of the magazine seat 62 (see FIG. 4). The spring 
83 has one end connected to the link 82 and an opposite end connected to 
the frame 2 at a suitable location. 
Referring to FIGS. 3 and 6, the adjusting rod 9 is mounted on the frame 2 
at the bottom near the front end thereof, having a driving gear 91 meshed 
with the toothed bottom wall 4111 on one side rail 411 of the box 41 of 
the circuit board assembly 4. By turning the adjusting rod 91, the box 41 
is moved in the sliding way 28, and therefore the position of the 
switching lever 51 of the micro-switch 5 is adjusted. 
Referring to FIG. 5, the linkage 1 comprises two opposite middle portions 
11 pivotally coupled to the two opposite ends of the first pivot axle 24, 
two opposite rear ends 12 inserted through the slot 26 on the frame 2 and 
coupled to two opposite sides of the valve block 31 of the electromagnetic 
valve, a front cross rod 13 linked to the front end 72 of the presser case 
assembly 7, and a striking plate 71 perpendicularly downwards extended 
from the front end 72. When the linkage 1 is oscillated to move the front 
corss rod 13 downwards, the striking plate 71 of the presser case assembly 
7 is forced into the staple magazine 61 of the magazine and tie plate 
assembly 6 causing a staple driven through the sheets of paper 10. 
Referring to FIG. 7, the circuit board of the circuit board assembly 4 
comprises a power switch SW1, a diode D1, two resistors R1 and R2, a 
central processing unit U1, a transistor Q1, and a diode TR1. When the 
switching lever 51 of the micro-switch 5 is touched, the power switch SW1 
is switched on to let electric current pass. Electric current from the 
power switch SW1 is filtrated through the diode D1 and then dropped by the 
resistors R1 and R2 to proivde a working voltage to the central processing 
unit U1. The central processing unit U1 has one contact pin constantly 
maintained at HI state. When the power switch SW1 is switched on, the 
transistor Q1 is turned on causing the diode TR1 to drive the valve block 
31 of the electromagnetic valve 3 for one stroke. Upon each triggering, 
the valve block 31 is reciprocated for one stroke and then immediately 
returned to the former position for a next stroke upon further triggering.