US3278101A

US3278101A - Electric stapler

Info

Publication number: US3278101A
Application number: US343803A
Authority: US
Inventors: Hatazaki Yasuzo
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 1963-02-14
Filing date: 1964-02-10
Publication date: 1966-10-11
Anticipated expiration: 1983-10-11

Description

Oct 11, 1956 YAsUZo HATAZAKI 3,278,101

ELECTRIC STAPLER Filed Feb. lO, 1964 4 Sheets-Sheet 1 F/g/ F/g. 3

ATTORNEYS Oct. 11, 1966 YAsUzo HATAZAKI 3,278,101

ELECTRI C STAPLER Filed Feb. lO, 1964 4 Sheets-Sheet 5 94m F/g. 6 55/6 /0/ 5 u 2Q ATTORNEKS Oct. 11, 1966 YAsuzo HATAzAKl ELECTRIC STAPLER 4 Sheets-Sheet 4 Filed Feb. l0, 1964 ATTORNEYS United States Patent G 3,278,101 ELECTRIC STAFLER Yasuzo Hatazalri, (Esedra, liapan, assigner to Matsushita Electric industrial Co., Ltd., Usaka, Espan, a corporation of .l'apan Fiied Feb. 10, 1%4, Ser. No. 343,863 Claims priority, application tapan, Feb. 14, 1963, 38/ 9,935, .1S/9,939; Apr. 15, 1963, Tait/28,1136, lig/28,041; May 10, 1963, Sti/35,108, Sii/35,113, EHS/35,117; May 16, 1953, SiS/36,734; Dec. 28, 1963, C19/24 2 Ciairns. (Ci. 227-7) This invention relates to ian electric stapler apparatus utilizing electromagnetic force for actuating it in which an electromagnet is magnetized automatically by insertion of sheets of paper to drive a staple into the sheets in order to fasten them together.

A principal featureof the present invention consists in that a relay is actuated, instantaneously by the charging current of a capacitor, thereby energizing an electromagnet instantaneously to produce an impulse of electromagnetic force in the electromagnet to drive a staple.

Another feature of the present invention allows for force control in that said capacitor is either variable in capacitance or intermediate circuit taps may be provided on the coil of the electromagnet over which electrical connection may be changed to adjust the electromagnetic force produced in the electronragnet to drive the staple with proper impulse force depending upon load on the staple, as, for example, thickness of the sheets .to be fastened or number of the sheets.

Still another feature of the present invention is to provide convenient means fior detecting presence of staples within a staple reservoir and indicating means visible from the exterior of the device.

Still another feature of the present invention consists in the provision of a switch which engages the sheets of paper to actuate 1an electromagnet when the sheets are inserted and which switch may be adjusted in its position to adjust the fastening position of the sheets.

Further features of the present invention include: an armature of the electromagnet which is adapted to move horizontally to suppress vibration; the whole apparatus being of a reduced size; resupply of staples being facilitated by providing a push button for making a slide case disposed within the staple reservoir readily extractable, the armature of the electromagnet being operatively connected to the staple magazine and a striking member for `driving a staple by means of a lever and other parts being so arranged iand adjusted as to reduce the size of the apparatus exceedingly.

The present invention will be now described in detail in conjunction with the accompanying drawings in which:

FIG. 1 shows a schematic front elevation of an electric stapler apparatus embodying the present invention;

FIG. 2 shows a schematic side elevation of the apparatus shown in FIG. l;

FIG. 3 shows a detailed ifront elevation of the apparatus shown in FIG. 1, the casing thereof being removed .to show the internal mechanism;

FIG. 4 shows a top plan view of the apparatus shown in FIG. l in detail, the casing thereof being also removed;

FIG. 5 is a side elevation in cross section of the apparatus shown in FIG. l, taken along a line A-A in FIG. 4;

FIG. 6 is ia rear view in cross section of the apparatus shown in FIG. l taken along a line B-B in FIG. 4;

FIG. 7 shows a fragmentary side elevation in cross section of the apparatus shown in FIG. 1 taken along a line C-C in FIG. 4;

FIG. 8 shows an exploded perspective view of principal ICC parts `of the internal mechanism of the apparatus shown in FIG. l; and

FIG. 9 shows an electrical wiring diagram tof the apparatus shown in FIG. l.

Referring to the drawings, particularly to FIGS. 1 to 5, a casing 2 made of synthetic resin is secured to a diecast base member 1 by means ot bolts 3. Between the front part of the base member 1 and the casing 2 there is provided a gap ttthrough which sheets of paper to be fastened together are inserted. The gap 4i presents the bottom Xof a staple magazine 5 containing staples. A staple clincliing anvil 6 is mounted on the base member 1. A lever S for a microswitch '7 for actuating the stapler apparatus protrudes through the gap 4 and a groove 9 for guiding the lever 8 is formed in the base member 1.

in operation, when sheets of paper to be fastened are inserted between the staple anvil 6 and the staple mag-azine 5, the lever 8 is depressed by the sheets and an electromagnet is magnetized by the making of the oontacts of the microswitch 7. At this moment, electromagnetic force of the electromagnet forces the staple magazine to move sharply against the staple anvil 6 while one of the staples contained in the staple magazine 5 is driven into the sheets by the driver. Thus the sheets are fastened together. In order to replenish the staple magazine with staples, a sliding case in the staple magazine 5 is adapted to be withdrawn by pushing a button 11 which projects `from the side of the base member 1. The sliding case may be inserted into and fixed within the staple magazine 5 by pushing the sliding case at its front face 61. Over the side of the base member 1 protrudes a knob 12 for adjusting the fastening position of the sheets. The rnicroswitch 7 and the lever 8 are moved in the direction shown by an arrow D by rotation of the knob 12 and thus the position of contact point between the sheet and the lever' 8 is changed in respect to the staple `anvil 6 so that the fastening position in the sheets may be adjusted. A transparent body 13 is mounted in front of the casing 2 and an indicating lamp 14 is arranged inside the casing near the transparent body 13. This indicating lamp 14 provides a means for indicating the presence of staples within the staple magazine 5. Thus when there are some staples in the staple magazine 5, the indicating lamp 14 is lighted thereby illuminating the transparent body 13. Rubber suction cup feet are mounted on the bottom of the base member 1.

Next the internal mechanism of the apparatus will be described in reference to FIGS. l to 8. The `upper rear portion P of the base member 1 is formed in an open dishlike shape. A xture 16 is secured to the base member, within this portion, by means of screws 17. An electromagnet 19 is secured to the fixture 16 at its upper face 18 by means of screws 211. The electromagnet 19 comprises an iron core 21, a magnetizing coil 22 and an armature 23. When the magnetizing coil 22 is energized, the armature 23 is attracted so that the end 24 of the armature 23 will project from the core 21. The staple magazine 5 is supported in seesaw manner on a support 25 which is secured within the fixture 16 on the base member 1 by means of screws 26 which pass through holes 126. A shaft 29 is mounted through holes 27 in the support member 25 and in alignment with holes 23 in the staple magazine 5. The staple magazine is therefore pivoted about the shaft 29. The staple magazine 5 is formed as an L-shaped member and is provided with a slot 39 in its front wall, locking holes 31 in its bottom wall and a hole 33 in its side wall 32, as shown in FIG. 8. A leaf spring 35 having a paw 34 is secured to the side wall 32 at a point Q, with the paw 34 projecting through the hole 33. A cover 37 having substantially V-shaped cross section and being formed with a guide groove 36 ta along the axis thereof is fitted on the top of the staple magazine 5. Tabs 38 of the cover 37 are inserted into the locking holes 31 and bent to fix the cover 37 to the magazine 5. A staple follower 39 is slidably mounted inside the cover 37 and a `guide piece 40, which is formed of a portion of the staple follower, protrudes slidably through said guide groove 36. A slide plate 43 is provided with a hole 41 and a projection 42 and slides on the upper surface of cover 37 to which it contacts. Namely, the slide plate 43 is mounted on the top of the cover 37, with a guide 44 thereof extending through the guide groove 36 to the back side of the top surface of the cover 37 from above said top surface. A portion 45 at the end of the guide 44 is flexed on the backside and in parallel to the top surface of the cover 37. The aforementioned guide piece 40 projecting from the guide groove 36 engages the hole 41 in the slide plate 43. This engagement of the guide piece 40 with the hole 41 combines the slide plate 43 with the staple follower 49 integrally and the top surface of the cover 37 is placed between the slide plate 43 and the staple follower 49. A guide 44 of the slide plate 43 is tted into the guide groove 36 and a portion 45 of the guide 44 is folded toward inside the cover 37. Thus the staple follower 39 and the slide plate 43 are guided by the guide groove 36 and slide as a unit.

A sliding case 46 having an inner case 48 is inserted into the staple magazine through an opening 47 in the front wall of the magazine 5. The legs 52 of staples 51 and side wall 53 of the staple follower 39 are tted slidably into gaps formed between the side walls of the sliding case 46 and the inner case 48. Thus the front end 54 of the staple follower 39 is adapted to engage with the adjacent end of the group of the staples 51. In this connection, the rear end 58 of a pin 57 which extends through a hole 56 formed in the rear wall 55 of the staple follower is fixed to the rear end of the staple magazine 5. A spring 60, which surrounds the pin 57, is interposed between the rear end 59 and the rear wall 55 of the staple follower 39 to urge constantly the staple follower 39 toward the front wall 61 of the sliding case 46. The side wall 50 is provided with a notch 62 with which the paw 34 of the leaf spring 35 engages. When the paw 34 is disengaged from the notch 62, the sliding case 46 is forced to move outwardly through the front opening 47 of the staple magazine 5 as the front wall of the sliding case 46 is driven by the front end 54 of the staple follower 39 which is urged by the spring 60. For the purpose of releasing the paw 34 of the spring 35 from the notch 62 of the sliding case 46, a pin 63 which is adapted to engage the end of the spring 35 is supported in two

lugs

64 and 65 formed in the base member 1. A stopper 66, mounted on the pin 63, is arranged between said two

lugs

64 and 65, and a spring 67 which is adapted to urge constantly the pushbutton 11 on the pin 63 outward of the base member 1. When the push button 11 is depressed, the pin 63 is displaced axially and the end of the pin 63 forces the spring 35 to disengage the paw 34 to the spring 35 from the notch 62 in the sliding case 46. A guide plate 69 encloses the front wall 68 of the staple magazine 5 and is spaced slightly therefrom. The guide plate is mounted by means of screws 71 and is provided with a slot 70 arranged in alignment with the slot in the front wall 68 of the staple magazine 5. A staple driver 72 having a connecting hole 73 is slidably fitted in the gap formed by the front wall 68 of the staple magazine 5 and the guide plate 69. The bottom face of the staple driver 72 moves inside of the front wall 61 of the sliding case 46 and strikes the top of one of the staples 51 contained within the sliding case 46 to drive the staple from the bottom of the staple magazine 5 toward the staple anvil 6. A microswitch 74 is provided for lighting the lamp 14 for indicating the presence of staples 51 within the sliding case 46. This microswitch 74 is mounted on the side wall of the staple magazine 5 with its button 75 adapted to effect switching action by engaging with the projection 42 upon sliding movement of the slide plate 43. Thus, if any staples are contained within the sliding case 46, the projection 42 of the slide plate 43 does not contact with the button 75 of the microswitch 74 since the front end 54 of the staple follower 39 contacts with the end of the stick of staples 51 and the staple follower 39 and the slide plate 43 are located in the middle of the staple magazine 5. This microswitch '74 is mounted on the side surface at the forward end of the staple magazine 5. On the other hand, the slide plate 43 is guided by the guide groove 36 together with the staple follower 39 and slides on the top surface of the cover 37 which is mounted on the magazine 5. When the slide plate 43 is positioned at the forward end of the top surface of the cover, the projection 42 of the slide plate 43 cornes into contact with the button 75 of the microswitch 74 and brings the microswitch 74 into the open state, whereas the slide plate 43 is not positioned at the forward end of the top surface of the cover 37 (i.e., when the slide plate 43 is positioned to the rear of the microswitch 74), the rffjection 42 does not corne into Contact with the button 75 of the microswitch 74, thus keeping the microswitch 74 in the closed position. This position of the slide plate on the top surface of the cover 37 is variable by the number of staples contained in the slide case 46. In other words, upon charging the staples 51 in the slide case 46 and then placing the slide case 46 in the staple magazine 5, one end the staples 51 contacts the front wall 61 of the slide case 46, while the other end thereof contacts the front end 53 and 54 of the staple follower 39 and, in that position, the staples 51 are pressed by the front end 53 and 54 against the front wall 61 of the slide case 46 by the force of spring 6i). Therefore, when no staples remain in the slide case 46, the staple follower 39 is positioned at the forward end of the staple magazine 5 with its front end 53 and 54 being in contact with the front wall 61 of the slide case 46 and the slide plate 43, connected to the staple follower 39, being positioned at the forward end at the top surface of the cover 37. On the contrary, when staples are present in the slide case 46, the staple follower 39 and the slide plate 43 are located rearwardly at a distance corresponding to the length of the staples, with the projection 42 on the slide plate 43 being located rearwardly of the button 75 of the microswitch 74 without depressing said button 75, i.e., the microswitch 74 is held in a closed position lighting the indicating lamp 14. When the staples within the sliding case 46 have been used up, the staple follower 39 and the slide plate 43 are forced to move forward by the action of the spring 60 and the projection 42 of the slide plate 43 depresses the button '75 of the microswitch 74 to open it. As a result, the indicating lamp is extinguished.

A pin 78 is extended through the hole 77 in the middle portion of a bell crank 76 with the both ends thereof being supported in bores S2 formed in ears 81 of the staple magazine 5 through spacers 79 and 3@ respectively. The bell crank 76 serves to transmit the movement of the armature 23 of the electromagnet 19 to the staple driver '72 and also to transmit the movement of the armature 23 to the staple magazine 5. Thus the bell crank '76 is pivoted about the pin 73. One end 83 of the bell crank 76 extends through the slot 70 to iit into a connecting hole 73 in the staple driver 72 and the other end of the bell crank 76 has a hole S4 through which a pin 85 extends. The ends of the pin 85 are supported by the end 24 of the armature 23 of the electromagnet 19 through the intermediary of spacers 86 and 37. In this connection, a resilient pad 8S is applied to the core 21 in order to obtain shock absorbing effect between the magnetic core 21 and the bell crank 76. A spring 89 is mounted between the bell crank 76 and the staple magazine 5 about the pin 78 and serves to urge constantly the armature 23 and the bell crank 76 in the directions shown by S and R', respectively. A spring 92 which is tensioned between a lug 90, formed by bending a portion of the top 18 of the fixture block 16, and a hole 91 in the ear 81 of the staple magazine forces the front opening 47 of the staple magazine 5 upward. A lever guiding plate 93 is secured to the upper surface 18 of the fixture 16 and has a tab 93. Since the side of the bell crank 76 pivots in contact with the tab 93 of the lever guiding plate 93 when the lever is pivoted about the pin 78 as a result of movement of the armature 23 of the electromagnet, an irregular swing in the direction along the axis of the

78 or 85 in the course of pivoting movement of the bell crank 76 is avoided. Accordingly, the motion of the armature 23 of the electromagnet can be transmitted to the staple driver 72 in a precise manner. Namely, play is provided between the ends 24 of the armature 23 and the core 21 so as to facilitate the movement of the armature 23, the ends 24 are movable somewhat axially of the pin 85. Similarly, in order to ease the movement of the bell crank 76, play is provided between the hole 84 and the pin 85, between the center hole in the spacer 87 and the pin 85 between the spacer 86 and the bell crank 76, between the spacer 87 and bell crank 76, between the end 24 of the armature 23 and the spacer 86, between the end 24 of the armature 23 and the spacer 87, between the hole 77 and the -pin 78, between the center hole in the spacer 79 and the pin 78, between the center hole in the spacer 80 and the pin 78, between the spacer 79 and the bell crank 76, between the spacer 80 and the bell crank 76, between the ears 81 of the staple magazine 5 and the spacer 79, and between the ears 81 of the staple magazine 5 and the spacer 80, wherefore the bell crank 76 is also displaceable axially of the pins '78 and 85. If the lever guiding plate 93 is not present here, the bell crank 76 swings irregularly in a lateral direction axially `of the

pins

78 and 85 along with the movement of the armature 23 and, as a result, the motion of the armature 23 cannot be transmitted to the staple driver 72 with accuracy. Against this, in the embodiment shown in the figures, there is provided the lever guiding plate 93 having a tab 93' and the spring 89 urges the armature 23 as well as the bell crank 76 in the direction shown by arrows S' and R respectively and simultaneously keeps the bell crank 76 always in pressure contact with the tabs 93 of the lever guiding plate 93. Such being the arrangement, the side surface of the bell crank 76 rotates in contact with the tab 93 of the lever guiding plate 93 as the bell crank 76 rotates about the pin 78, the bell crank makes no lateral movement in the axial direction of the pin 79 or 8S. Consequently, the motion of the armature 23 can be transmitted to the staple driver 72 with high accuracy.

The microswitch 7 for actuating the stapler apparatus is mounted on the head of a 'guide plate 94 which has formed in its side a cut bent lug 95 which is slidably fitted into a slot `96 formed in the side wall of the fixture 16. The guide plate 94 is mounted Ion the side wall of the fixture 16 by means of a screw 97 and a nut 98 so that the `guide plate may slide `horizontally with the iug 95 being fitted into the slot 96 las described above. Thus `the screw 97 extends through the slot 96 with the head youtwardly projecting from the side surface of the fixture 16 and further the shaft `101 is inserted in a spring 104 with fthe Iknob 12 fixed to the tip end thereof. In the adjusting shaft l101, there is formed a cutaway portion 105, while the disc 103 is formed at its center with a partiaily flattened surface or circular center hole 106 through which the cutaway portion extends. By the engagement of the cutaway portion =105 on the shaft 101 with the center hole 106, the disc 103 is prevented from rotating with respect #to the shaft 101 and rotates integrally with [the shaft 101 as the latter rotates. The knob 12 has on its peripheral surface a set screw 12a which is screwed in said knob in the direction perpendicular to the axis of the shaft 101. After the knob 12 is mounted to the end extremity of the shaft 101, the set screw 12a is tightened by screwing against Athe cutaway portion 105 of the shaft 101 to thereby -x the knob 12 to the end of the shaft l101 so that the knob 12 rotates integrally with the shaft 101. ABetween the knob 12 and the disc 10'3 is mounted a spring 104, by the force of whichthe disc 103 is pressed against the side surface of `the fixture 16. Since the gear Wheel 100 meshes with the rack 99, when `the -knob y12 is rotated, the gear wheel 100 is rotated and, as a result, the microswitch mounted on the guide plate 94, which is engaged with said gear 100, moves horizontally in the direction shown by arrow D. Moreover, the side wall of the fixture 16 is provided with a plurality -of proje-ctions 108 which are adapted to lit into a plurality `of recesses 107 in the retaining disc 103. As the adjusting shaft is turned, the projections 108 are snap-fitted finto the succeeding recesses 107 so that the angular position of the shaft 101 is prevented from slipping ou-t of any one of predetermined positions under `the influence of vibration.

An electromagnetic relay 121 is secured to the rear portion of .the base member 1 by means of screws 109 and an electric insulator b-oard 110 is mounted on the side yof the electromagnetic relay 121. A resistor 111 and a diode clamp 112 are disposed on the insulator board 110. They are covered by insulating resin to fix them in place. An electric insulator board 114 is secured by a screw 115 Ito an ear 113 formed in the rear end of the fixture 16. `O11 the insulator board 114 there are disposed a capacitor 116, a rectifier 117 and

resistors

118 and 119 and they are covered by insulating resin to fix them in place.

Next the electrical circuit for the electric stapler apparatus will be explained in reference to FIG. 9. The magnetizing coil 22 of the electromagnet 19 is connected across terminals W and W of a power source through a contact 120 of the electromagnetic relay 121. A coil 122 of the electromagnetic relay 121 is connected across the terminals W and W through the capacitor 116, the rectifier 117, the microswitch 74 and the resistor 118 when fthe switch contact `of switch 7 contacts the stationary contact m. Further, the resistors 111 and 118, the indicating lamp 14 and rthe microswitch 74 are connec-ted in series across the terminals W and W of the power source and fthe resistor 119 is connected across the electrodes of the capacitor 116 i-n series with the contact n of the microswitch 74. The diode clamp 112 is connected across the coil 122 of the electromagnetic relay 121 Ito suppress transient high voltage which might be produced across the coil 122 and hence sparking discharge across the contact of microswitch 74.

When there are some staples within the staple magazine 5 the contact of the microswi'tch 74 is closed, the indicating lamp 14 is lighted and the contact of the change lover microswitch 7 is closed on the pole n. But upon `insertion yof the sheets of paper to be fastened into fthe Afront part of the stapler apparatus the lever of the change over microswitch 7 is urged by the sheets to contact against the pole m. As a result, charging current flows to the capacitor 116 through the resistor 118 and the rectifier 117 and through the coil 122 of the electromagnetic relay 121 to magnetize it and thus fthe contact 120 is closed thereby magnetizing the coil 22 of the electromagnet so that one of the staples within the staple magazine 5 is driven into the sheets lof paper by means of the previously mentioned linkage comprising the armature 23, the `lever 76, the staple magazine 5 and the staple driver 72. Since fthe charging current of the capacitor 116 effects magnetization of the coil 122 of the electromagnetic 'relay 121, lthe coil 122 is magnet-ized instantaneously so that closure of the contact 120 is also carried out instantaneously. Thus the staple 51 is driven into `the sheets instantaneously and impulsively. Thus, when sheets of papers to be stapled are inserted in the front portion of the stapler, the lever 8 of the changeover microswitch 7 is pressed by the sheets of paper, whereupon the contact of the microswitch departs from the pole n to come into contact with the pole m and, as a result, `high charging current flows initially, as the capacitor 116 is progressively charged, itsterminal voltage is raised so that the charging current is decreased and magnetization of the coil 122 of the electromagnet 121 is stopped in due time. In this respect, magnetizing time of the coil 122 is -ordinarily desirable to be about 100 milliseconds. This time may he adjusted by changing the capacity of the capacitor 116 and the value of the resistor 118. When the sheets areremoved from the stapler, the con-tact of the microswitch 7 is changed over the contact n to discharge the charge stored in the capacitor 116 through the resistor 119. Thus the stapling device is restored to the original state.

According to the present invention, since one of the staples is driven by an impulsive electromagnetic force produced in an electromagnet by causing current to flow instantaneously through the coil of the electromagnet, the circuit of the stapler apparatus conducts only when the apparatus is operated so that power loss may be reduced. Moreover, when the stapler apparatus is not in operation, a discharging resistance is connected across the capacitor to cause it to discharge rapidly so that repeated driving of the staples may be carried out at high speed and reliably. Furthermore, in the electric stapler apparatus according to the invention, movement of a staple driver serves to open and close a microswitch which is connected in series in the circuit of an electromagnetic relay. Consequently when staples within a staple magazine have been used up the microswitch is opened so that the stapler apparatus does not operate to drive the staples even if the sheets of paper are inserted into the stapler so that not only ineffective operation is prevented but lack of staples may be detected. Since an armature of the electromagnet of the stapler apparatus according to the present invention travels horizontally, the whole structure of the stapler apparatus is subject to lower impulsive vibration than that encountered in the conventional apparatus in which the armature moves vertically and the stapler may be reduced in height. A guide plate is provided for guiding pivotal movement of the bell crank which connects the armature of the electromagnet with a striking member for driving staples. Thus the bell crank pivots in contacting relation with the guide plate, and an irregular transversal swing during the pivotal movement is avoided so that horizontal movement of the armature of the electromagnet is transmitted effectively and uniformly to a staple driver to drive always the staples positively.

In the staple magazine according to the present invention, a leaf spring having a paw is secured at its end on the side wall of the staple magazine and this paw projects inside the staple magazine through a hole formed in its side wall to engage releasably with a notch in the side wall of a sliding case inserted in the staple magazine. A pin of a push button bears against the other end of the leaf spring and the sliding case is urged forward by a coil spring. Thus as the push button is depressed, the paw on the leaf spring is disengaged from the notch of the sliding case so that the sliding case may be removed by the resiliency of the coil spring in front of the staple magazine to facilitate replenishment of the staples. When the slide case is pressed backward against the force of the coil spring, the paw of the leaf spring engages again with the notch in the side wall of the sliding case so that it rests easily in place within the staple magazine.

Further, according to the present invention, a changeover microswitch for operating the stapler apparatus to drive staples into sheets of paper to be fastened is provided with a lever which is pressed by the sheets of paper to switch the contact of the switch to energize the electromagnet for driving the staples. In this connection, the changeover switch is mounted on a guide plate which is slidable axially and the guide plate is provided with a rack which meshes a gear wheel mounted rigidly on the end of an adjusting shaft by rotation of which the change-over switch moves axially along with the lever. Accordingly the distance between the end of the sheets and the position where the sheets are tto be fastened can be adjusted by setting of the position of the lever of the change-over switch by properly rotating the adjusting shaft. Moreover, since the adjusting shaft is prevented from rotating freely by provision of a projection in the side wall of the fixture and recesses in the retaining disc which nonrotatably accommodates the adjusting shaft so that the projection may fit releasably into one of the recesses in the retaining disc, the adjusting shaft does not slip out of the preset angular position by the effect of vibration so that the change-over switch may be positively fixed in any one of the predetermined positions.

IFurthermore, in the electric stapler apparatus according to the present invention since electrical circuit elements such as capacitors, resistors and a rectifier are disposed compactly in a space behind the base member, whole structure of the stapler apparatus can be reduced in size.

What I claim is:

1. An electric stapler apparatus comprising a base member; a fixture mounted substantially in the middle of said base member; an electromagnet mounted on said fixture having an armature which is movable horizontally; a substantially L-shaped staple magazine supported on said base member having a case, adapted to receive a stick of staples, slidably inserted in a front opening thereof; a staple driver slidably fitted to a head portion of said L-shaped staple magazine, said staple driver being actuated to drive one of the staples into sheets of paper to be fastened together; a bell-crank supported by said staple magazine and pivotable about the center thereof, opposite ends of said bell-crank being connected with said armature of said electromagnet and said staple driver, respectively; a leaf spring having a paw and secured at one end to a side wall of said staple magazine; a notch formed in a side wall of said sliding case, said paw eX- tending through a hole formed in said side wall of said staple magazine releasably engaging with said notch; a pin associated with a push button projecting from the side of said base member and bearing against the other end of said leaf spring; a staple follower fitted slidably into said sliding case for pressing an end of said plurality of staples, a spring resiliently bearing against said staple follower; a lamp for indicating presence of the staples within said sliding case; a microswitch for energizing said indicating lamp according to the position of said staple follower in said sliding case; a guide plate mounted on a side wall of said fixture for movement in a horizontal direction; a change-over switch mounted on said guide plate for energizing an electromagnetic relay, a depending lever on said guide plate actuated by the insertion of the sheets of paper to be fastened, said lever actuating said changeover switch upon being actuated, said electromagnetic relay being arranged in the rear portion of said base member; a rack formed in said guide plate; an adjusting shaft having a gear wheel mounted on one end thereof and meshing with said rack, said adjusting shaft being rotatably mounted in said fixture, a locking mechanism for fixing said adjusting shaft in any one of predetermined angular positions; an insulator plate mounted in the rear portion of said base member, a capacitor, a charging resistor, a discharging resistor and a rectifier mounted on said insulator plate, said coil of said electromagnet being connected across terminals of a power source through a contact of said electromagnetic relay, said electromagnetic relay having a coil connected across said terminals of said power source in series with said capacitor, said change-over switch, said rectifier, said microswitch and said charging resistor, said `discharging capacitor resistor being connected across said capacitor through said change-over switch, said lamp for indicating presence of the staples within said sliding case being connected across said terminals of said power source; a transparent body for transmitting light emitted by said lamp and a casing secured to said base member for covering all of the above described components of said electric stapler apparatus.

2. An electric stapler apparatus comprising a base member; a fixture mounted substantially in the middle of said base member; an electromagnet mounted on said fixture having an armature which is movable horizontally; a substantially L-shaped staple magazine supported on said base member and having a oase slidably inserted in a front opening thereof and adapted to receive a plurality of staples; a staple driver slidably fitted to a head portion of said L-shaped staple magazine, said staple driver being actuated to drive one of the staples into sheets of paper to be fastened together; a bell-crank supported by said staple magazine and pivotable about the center thereof, opposite ends of said bell-crank being connected with said armature of said electromagnet and said staple driver respectively; a leaf spring having a paw and secured at one end to a side wall of said staple magazine; a notch formed in a side wall of said sliding case, said paw extending through a hole formed in said side wall of said staple magazine and releasably engaging with said notch; a pin associated with a push button projecting over the face of said base member and bearing against the other end of said leaf spring; a staple follower iitted slidably into said sliding case for pressing an end of said plurality of staples, a spring resiliently bearing against said staple follower; a microswitch adapted to be opened by means on said staple follower when sa-id plurality of staples in said case is exhausted; a guide plate mounted on a side wall of said fixture for movement in a horizontal direction; a changeover switch mounted on said guide plate for selectively energizing an electromagnetic relay; a depending lever on said guide plate movable by the insertion of the sheets of paper to be fastened to actuate said changeover switch; a rack formed in said guide plate; an adjusting shaft having a gear wheel mounted on one end thereof and meshing with said rack, said adjusting shaft being rotatably mounted in said fixture and being provided with a locking mechanism for lfixing said adjusting shaft in any one of a number of predetermined angular positions; an insulator plate mounted in the rear portion of said base member, a capacitor, a charging resistor, a discharging resistor and a rectifier mounted on said insulator plate; and a case to cover all of said elements of said apparatus mounted on said base member, said coil of said elec'tromagnet being connected across terminals of a power source through a contact of said electromagnetic relay, said electromagnetic relay having a coil connected across said terminals of said power source in series with said capacitor, said changeover switch, said rectifier, said microswitch and said charging resistor, said discharging resistor being connected across said capacitor through said changeover switch, and said electromagnetic relay being actuated instantaneously by the charging current of said capacitor to make said electromagnetic coil instantaneously conduct to produce impulsive electromagnetic force to drive the staples into the sheets of paper to be fastened.

References Sited by the Examiner UNITED STATES PATENTS 2,205,861 6/ 1940 VOussani 1-409 XR 2,403,947 7/1946 Oussani 1-409 XR 2,545,397 3/1951 Wampler 1 417 XR 2,643,307 6/1953 Geel 1-409 XR 2,656,537 10/1953 Geel 1-409 2,719,528 10/ 1955 Gabrielsen 221-6 XR 2,801,414 8/1957 vMueller 1-415 XR 2,910,700 11/1959 De Paolo 1-409 XR 2,957,174 10/1960 Oussani 1-409 3,080,036 3/19613 Robbins et al. 221-6 XR 3,141,171 7/1964 Doyle et al. 1-44.6

GRANVILLE Y. CUSTER, JR., Primary Examiner.

Claims

1. AN ELECTRIC STAPLE APPARATUS COMPRISING A BASE MEMBER; A FIXTURE MOUNTED SUBSTANTIALLY IN THE MIDDLE OF SAID BASE MEMBER; AN ELECTROMAGNET MOUNTED ON SAID FIXTURE HAVING AN ARMATURE WHICH IS MOVABLE HORIZONTALLY; A SUBSTANTIALLY L-SHAPED STAPLE MAGAZINE SUPPORTED ON STICK BASE MEMBER HAVING A CASE, ADAPTED TO RECEIVE A STICK OF STAPLES, SLIDABLY INSERTED IN A FRONT OPENING THEREOF; A STAPLE DRIVE SLIDABLY FITTED TO A HEAD PORTION OF SAID L-SHAPED STAPLE MAGAZINE, SAID STAPLE DRIVER BEING ACTUATED TO DRIVE ONE OF THE STAPLES INTO SHEETS OF PAPER TO BE FASTENED TOGETHER; A BELL-CRANK SUPPORTED BY SAID STAPLE MAGAZINE AND PIVOTABLE ABOUT THE CENTER THEREOF, OPPOSITE ENDS OF SAID BELL-CRANK BEING CONNECTED WITH SAID ARMATURE OF SAID ELECTROMAGNET AND SAID STAPLE DRIVER, RESPECTIVELY; A LEAF SPRING HAVING A PAW AND SECURED AT ON END TO A SIDE WALL OF SAID STAPLE MAGAZINE; A NOTCH FORMED IN A SIDE WALL OF SAID SLIDING CASE, SAID PAW EXTENDING THROUGH A HOLE FORMED IN SAID SIDE WALL OF SAID STAPLE MAGAZINE RELEASABLY ENGAGING WITH SAID NOTCH; A PIN ASSOCIATED WITH A PUSH BUTTON PROJECTING FROM THE SIDE OF SAID BASE MEMBER AND BEARING AGAINST THE OTHER END OF SAID LEAF SPRING; A STAPLE FOLLOWER FITTED SLIDABLY INTO SAID SLIDING CASE FOR PRESSING EN END OF SAID PLURALITY OF STAPLE, A SPRING RESILIENTLY BEARING AGAINST SAID STAPLE FOLLOWER; A LAMP FOR INDICATING PRESENCE OF THE STAPLES WITHIN SAID SLIDING CASE; A MICROSWITCH FOR ENERGIZING SAID INDICATING LAMP ACCORDING TO THE POSITION OF SAID STAPLE FOLLOWER IN SAID SLIDING CASE; A GUIDE PLATE MOUNTED ON A SIDE WALL OF SAID FIXTURE FOR MOVEMENT IN HORIZONTALY DIRECTION; A CHANGE-OVER SWITCH MOUNTED ON SAID GUIDE PLATE FOR ENERGING AN ELECTROMAGNETIC RELAY, A DEPENDING LEVER ON SAID GUIDE PLATE ACTUATED BY THE INSERTION OF THE SHEETS OF PAPER TO BE FASTENED, SAID LEVER ACTUATING SAID CHANGEOVER SWITCH UPON BEING ACTUATED, SAID ELECTROMAGNETIC RELAY BEING ARRANGED IN THE REAR PORTION OF SAID BASE MEMBER; A RACK FORMED IN SAID GUIDE PLATE; AN ADJUSTING SHAFT HAVING A GEAR WHEEL MOUNTED ON ONE END THEREOF AND MESHING WITH SAID RACK, SAID ADDJUSTING SHAFT BEING ROTATABLY MOUNTED IN SAID FIXTURE, A LOCKING MECHANISM FOR FIXING SAID ADJUSTING SHAFT IN ANY ONE OF PREDETERMINED ANGULAR POSITIONS; AN INSULATOR PALTE MOUNTED IN THE REAR PORTION OF SAID BASE MEMBER, A CAPACITOR, A CHARGING RESISTOR, A DISCHARGING RESISTOR AND A RECTIFIER MOUNTED ON SAID INSULATOR PLATE, SAID COIL OF SAID ELECTROMAGNET BEING CONNECTED ACROSS TERMINALS OF A POWER SOURCE THROUGH A CONTACT OF SAID ELECTROMAGNETIC RELAY, SAID ELECTROMAGNET RELAY HAVING A COIL CONNECTED ACROSS SAID TERMINALS OF SAID POWER SOURCE IN SERIES WITH SAID CAPACITOR, SAID CHANGE-OVER SWITCH, SAID RECTIFIER, SAID MICROSWITCH AND SAID CHARGING RESISTOR, SAID DISCHARGING CAPACITOR RESISTOR BEING CONNECTED ACROSS SAID CAPACITOR THROUGH SAID CHANGE-OVER SWITCH, SAID LAMP FOR INDICATING PRESENCE OF THE STAPLES WITHIN SAID SLIDING CASE BEING CONNECTED ACROSS SAID TERMINALS OF SAID POWER SOURCE; A TRANSPARENT BODY FOR TRANSMITTING LIGHT EMITTED BY SAID LAMP AND CASING SECURED TO SAID BASE MEMBER FOR COVERING ALL OF THE ABOVE DESCRIBED COMPONENTS OF SAID ELECTRIC STAPLER APPARATUS.