Motor driven stapler - Patent Review 5474222

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BACKGROUND OF THE INVENTION

The present invention relates to a staple feeding apparatus for taking out away from a staple cartridge the lowermost sheet-shaped staple among a plurality of sheet-shaped staples received in the staple cartridge in the multi-layered structure wherein the staple cartridge is fitted into a magazine turnably arranged in a motor driven stapler. In addition, the present invention also relates to a staple feeding mechanism for a motor driven stapler which assures that a plurality of sheet-shaped staples, received in a staple cartridge in the multi-layered structure, are successively taken from the staple cartridge to the foremost end of a magazine in order from the lowermost sheet-shaped staple among the foregoing plurality of sheet-shaped staples received in the staple cartridge.

A hitherto known staple feeding apparatus of the foregoing type is constructed such that a feeding unit, including a feeding belt or a feeding roller disposed below the bottom of a staple cartridge, is arranged in such a manner as to allow the lowermost staple, among a plurality of sheet-shaped staples received in a staple cartridge, to come in tight contact with the upper surface of the feeding belt or the Seeding roller of the feeding unit. As the feeding unit is driven by an electric motor, the lowermost staple is taken from the staple cartridge to reach the foremost end of a magazine turnably arranged in a motor driven stapler (see, e.g., a Japanese patent examined. Publication No. 1-25672).

With the conventional staple feeding apparatus constructed in the above-described manner, the intensity of feeding power required to remove each staple usually varies depending on a magnitude of the frictional resistance present between the lowermost sheet-shaped staple and the upper surface of the feeding unit. The larger the frictional resistance, the larger the feeding power required for the foregoing purpose. Thus, the lowermost staple can be reliably fed from the staple cartridge to the magazine in the presence of the high frictional resistance. Since a plurality of sheet-shaped staple cartridges received in the staple cartridge are normally forced from above by the resilient force of a spring means, a large amount of frictional resistance can be present between the adjacent upper and lower staples. Thus, a malfunction can arise where part of an adhesive, that connects adjacent straight staples staple to each other, adheres to the upper or lower sheet-shaped staple or a staple is partially entangled with the upper or lower sheet-shaped staple. In such a case, a higher amount of feeding power must be applied to the lowermost staple in order to reliably feed it to the magazine after this lower staple is separated from a the staple located above it. In practice, the frictional resistance present between the lowermost staple and the upper surface of the feeding unit is sometimes not large enough to reliably feed the lowermost sheet-shaped staple from the staple cartridge.

In addition, with the conventional staple feeding mechanism constructed in the above-described manner, a drawback is that it becomes complicated in structure since the driving power is required for actuating the staple feeding mechanism is typically generated by the electric motor. To obviate the foregoing drawbacks to a staple feeding mechanism for removing a staple from a staple cartridge when the staple comes in contact with a feeding roller in a feeding that has a ratchet mounted on one end of a roller shaft for the feeding roller, and an actuating unit. The actuating unit includes a pulling pawl and a pushing pawl and is mounted on a pair of driving links. The driving links are adapted to drive a magazine in such a manner that when the driving links are turnably displaced in the downward direction, the pulling pawl is engaged with the ratchet, and subsequently, when the driving links are turnably displaced in the upward direction, the pushing pawl is engaged with the ratchet. Thus, the ratchet rotates during the engagement of the pushing pawl with the ratchet and the staple is delivered in the forward direction by a distance corresponding to the rotation of the ratchet.

With the proposed staple feeding mechanism however, there arises a necessity for arranging an additional unit for normally biasing of the actuating unit toward the ratchet so as to allow the pulling pawl to be reliably engaged with the ratchet. In addition, since the ratchet is rotated by a small angle with each working stroke of the driving links the motor driven stapler should be repeatedly actuated until a staple can be struck by a driver when the staple cartridge is replaced with a new one.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the aforementioned background and its object resides in providing a staple feeding apparatus for a motor driven stapler which assures that the lowermost sheet-shaped staple among a plurality of sheet-shaped cartridges received in a staple cartridge is reliably fed to the foremost end of a magazine in the motor driven stapler while a large amount of feeding/driving power is applied to the lowermost sheet-shaped staple.

To accomplish the above object, a first aspect of the present invention provides a staple feeding apparatus for a motor driven stapler wherein a magazine fitted with a staple cartridge is turnably arranged above a base frame to turn about a support shaft in an upward and downward direction. The staple cartridge is such that a plurality of sheet-shaped staples, each having a series of straight staples successively connected to each other side by side are received therein in the multi layered structure, the lower ends of a front wall and a rear wall of the staple cartridge are kept opened, and when the magazine is turned in the downward direction by rotationally driving an electric motor, a straight staple located at the foremost end of each sheet-shaped staple is formed to exhibit substantially inverted U-shaped contour and then struck by a driver toward a stapling board disposed on the base frame so as to allow the foot of the staple to penetrate through the papers that are to be stapled. The staple feeding apparatus comprises a feeding member arranged to slidably move, from an opening portion at the lower end of the rear wall of the staple cartridge, in the direction of the feeding of each sheet shaped cartridge relative to the magazine and including a contact portion adapted to come in contact with the rear end of the lowermost staple among a plurality of sheet shaped staples received in the staple cartridge in the course of the displacement of the feeding member in the forward direction and a supporting portion immovably disposed at the position behind the magazine, that the feeding member includes an engagement portion adapted to be engaged with the supporting portion so as to allow the feeding member to slidably move in the opposite direction to the direction of feeding of each sheet-shaped staple when the magazine is turned in the downward direction, and that spring means is bridged between the magazine and the feeding member so as to allow the feeding member to slidably move in the direction of feeding of each sheet-shaped staple when the magazine is turned in the upward direction and the feeding member is released from the-engaged state caused by the engagement of the feeding member with the supporting portion.

As the magazine is turned in the downward direction, the engagement portion of the feeding member is engaged with the supporting portion of the magazine so that the feeding member is slidably displaced in the opposite direction to the direction of feeding of each sheet-shaped staple. This causes the contact portion on the feeding member, to be displaced in the rearward direction relative to the magazine. On the contrary, when the feeding member is released from the engagement state which is caused by the engagement of the feeding member with the supporting portion as the magazine is turned in the upward direction, the feeding member is slidably displaced in the direction of feeding of each sheet-shaped staple by the resilient force of the tension spring. This causes the contact portion on the feeding member to be displaced in the forward direction relative to the magazine. At this time, the contact portion engages with the rear end of the lowermost staple. Thus, the lowermost sheet-shaped staple is removed from the fore wall of the staple cartridge by a distance equal to the distance of the forward displacement of the contact portion of the staple cartridge inside of the rear wall.

In such manner, each sheet-shaped staple is forced by the resilient power of the tension spring applied to the rear end thereof. Incidentally, the thrusting power given by the tension spring is sufficiently larger than the frictional resistance present between the lower surface of the sheet-shaped staple and the feeding member. For this reason, even in case where the lowermost staple partially adheres to a subsequent staple located above the foregoing one or partial entanglement occurs therebetween, the lowermost sheet-shaped staple can be reliably removed from the staple cartridge by a sufficiently high force extended by the tension spring. Consequently, a plurality of sheet-shaped staples received in the staple cartridge can be successively removed without fail from the staple cartridge by repeating the foregoing steps.

In addition, the present invention has been made in consideration of the aforementioned background and its object resides in providing a staple feeding mechanism or a motor driven stapler wherein the staple feeding mechanism is simple in structure, and moreover, a quantity of feeding of a straight staple attainable per each stroke of driving links can substantially be increased.

To accomplish the above object, a second aspect of the present invention provides a staple feeding mechanism for a motor driven stapler wherein a magazine fitted with a staple cartridge is turnably arranged above a base frame to turn about a support shaft in an upward and downward direction. The staple cartridge is such that a plurality of sheet-shaped staples, each having a series of straight staples successively connected to each other side by side, are received in the multi-layered structure. The lower end of a fore wall of the staple cartridge and the bottom of the same are kept opened and a pair of driving links, disposed on the opposite sides of the magazine, are turnably arranged to turn about the support shaft in the upward and downward directions. When the magazine is turned via the driving links, by rotationally driving an electric motor, a straight staple, delivered to the foremost end of the magazine, is formed by a forming plate to exhibit a substantially inverted U-shaped contour and then struck by a driver so as to allow the feet of the staple to penetrate through the papers to be stapled together. A feeding roller is disposed directly below the bottom of the staple cartridge and a ratchet, operatively associated with the feeding roller, is disposed on the one side of the magazine and a ratchet lever, which is molded of a synthetic resin or the like to exhibit an inverted U-shaped contour while including a fore lever portion and a rear lever portion, is fixedly secured to one of the driving links. A pushing pawl is formed at the foremost end of the fore lever portion of the ratchet lever and at least one pulling pawl is formed at the foremost end of the rear lever portion of the same. When the driving links are turnably driven in the downward direction, the pushing pawl on the fore lever portion of the ratchet lever engages with the ratchet, causing the latter to be stepwise rotated in the forward direction. When the driving links are turnably driven in the upward direction, the pulling pawl on the rear lever portion of the ratchet lever is brought in engagement with the ratchet, causing the latter to be likewise stepwise rotated in the forward direction. As the feeding roller operatively associated with the ratchet is stepwise rotated in the forward direction, each sheet-shaped staple is fed in the forward direction while coming in contact with the feeding roller.

When the driving links are turnably driven in the downward direction, the pushing pawl on the fore lever portion of the ratchet lever in engages with a pawl teeth on the fore side of the ratchet, causing the later to be stepwise rotated in the forward direction. When the driving links are turnably driven in the upward direction, the magazine is turnably driven in the upward direction but the magazine is stopped in the course of the turning movement of the driving links. Since the driving links can be turnably driven further in the upward direction, the upper pulling pawl on the rear lever portion of the ratchet lever engages with the ratchet, causing the latter to be stepwise rotated in the forward direction. The ratchet is repeatedly stepwise rotated in the forward direction every time the magazine is turned in the downward direction and then turned in the upward direction, and the feeding roller is stepwise rotated in the forward direction. Thus, the lowermost staple, received in the staple cartridge, is removed from the staple cartridge and then delivered in the forward direction in the presence of frictional resistance between the lowermost staple and the feeding roller while maintaining the contact state therebetween.

Since the ratchet lever is molded of a synthetic resin or the like to exhibit an inverted U-shaped contour, the there is no necessity for arranging a biasing unit for normally biasing the ratchet lever toward the ratchet side like conventional staple feeding mechanisms. Thus, in addition to an advantageous effect that the staple feeding mechanism is simple in structure. The number of each sheet-shaped staple attainable per single working stroke of the driving links can substantially be increased since the ratchet is stepwise rotated in the forward direction every time the driving links are turnably driven.

It should be noted that when two pulling pawls are formed on the rear lever portion of the ratchet lever, the number of staples attainable per each working stroke of the driving links can substantially be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a motor driven stapler to which the present invention is applied.

FIG. 2 is a side view of the motor driven stapler shown in FIG. 1.

FIG. 3 is a partially cutaway side view of the motor driven stapler.

FIG. 4 is a schematic side view of the motor driven stapler, particularly showing a mode of operation of a mechanism for turnably driving a magazine.

FIG. 5 is an exploded perspective view of a magazine, a pair of driving links and a base frame each of which is shown in the disassembled state.

FIG. 6 is an exploded perspective view of a magazine which is shown in the disassembled state.

FIG. 7 is a perspective view of a staple cartridge.

FIG. 8 is a fragmentary enlarged sectional view of a forming/striking section formed on the magazine.

FIG. 9(a) is a fragmentary illustrative view which shows that a substantially inverted U-shaped staple is struck by a driver in a forming/striking section, and FIG. 9(b) is a fragmentary illustrative view which shows that a straight staple is bent by a forming plate in the forming/striking section to exhibit a substantially inverted U-shaped contour.

FIG. 10(a), FIG. 10(b), FIG. 10(c) and FIG. 10(d) show a mode of operation of a staple feeding apparatus constructed according to the present invention.

FIG. 11(a), FIG. 11(b), FIG. 11(c) and FIG. 11(d) show a mode of operation of a staple feeding mechanism constructed according to the present invention.

FIG. 12 is an exploded perspective view of a magazine and a staple cartridge, showing essential components constituting the magazine and the staple cartridge in the disassembled state.

FIG. 13 is a fragmentary side view of the motor driven stapler to which the present invention is applied.

FIG. 14 is an illustrative side view of the motor driven stapler, schematically showing a mode of operation of the same.

FIG. 15(a) is an enlarged front view of the magazine, showing that the face plate is raised and FIG. 15(b) is a fragmentary side view of the magazine shown in FIG. 15(a).

FIG. 16(a) is an enlarged front view of the magazine, particularly showing that the face plate is forcibly displaced in the downward direction, and FIG. 16(b) is a fragmentary side view of the magazine shown in FIG. 16(a).

FIG. 17 is a side view of the motor driven stapler at the time when a paper stapling operation is started.

FIG. 18 is a side view of the motor driven stapler in the intermediate state of the paper stapling operation.

FIG. 19 is a side view of the motor driven stapler at the time when the stapling operation is completed.

FIG. 20 is a perspective view of a modified stapling board of the motor driven stapler according to the present invention.

FIG. 21(a), FIG. 21(b) and FIG. 21(c) show an operation of the modified stapling board shown in FIG. 20.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference to the accompanying drawings which illustrate a preferred embodiment thereof.

FIG. 1 and FIG. 2 show a motor driven stapler to which the present invention is applied. The motor driven stapler is constructed in such a manner that a magazine 2 fitted with a staple cartridge 4 having a plurality of sheet-shaped staple received therein in a multi-layered structure, is turnably arranged above a base frame 1 to turn about a support shaft in an upward and downward direction, and when the magazine 2 is turned in the downward direction by rotationally driving an electric motor 3, a straight staple located at the foremost end of each sheet is removed from the staple cartridge 4 and formed by a forming plate 31 to exhibit a substantially inverted U-shaped contour and then struck by a driver 32 towards a stapling board 5 disposed at the fore end part of the base frame 1 so as to allow the feet of the substantially inverted U-shaped staple to be penetrated through the papers 6 to be stapled together on the stapling board 5. In other words, the motor driven stapler comprises a magazine driving mechanism for turnably driving the magazine 2 to turn about the support shaft 15 in an upward and downward direction, a staple forming and striking mechanism then forms each straight staple received in the magazine 2 by the forming plate 31 to exhibit a substantially inverted U-shaped contour and then striking the substantially inverted U-shaped staple by the driver 32 toward the stapling board 5, and a staple feeding mechanism for delivering each straight staple received in the magazine 2 to the staple forming/striking mechanism. The foregoing three mechanisms will NDW be described in detail.

First, the magazine driving mechanism for turnably driving the magazine 2 in the upward and downward directions will be described. As shown in FIG. 1, FIG. 2 and FIG. 5, a pair of upright standing pieces 1a are formed on the opposite sides of the base frame 1 at the central part of the latter and a single upright standing piece 1b is formed on the right-hand side of the base frame 1 at the rear part of the latter. An electric motor 3 and a plurality of intermediate gears 7, operatively connected to an output shaft of the electric motor 3, are arranged on the rear upright standing piece 1b. A driving shaft 8 is bridged between both the central upright standing pieces 1a so that a driving gear 9 fixedly mounted on the driving shaft 8, at the right-hand end of the latter meshes with the intermediate gears 7. An eccentric cam 10 fixedly mounted on the driving shaft 8 at the central part of the latter, is located at the intermediate position between the central upright standing pieces 1a. A magazine 2 and a pair of driving links 11 are arranged on the base frame 1 located on the opposite sides of the magazine 2. The support shaft 15 extends through shaft holes 12, at the rear lower end of the magazine 2, and shaft holes 13 at the rear lower ends of the driving links 11, so that the magazine 2 and the driving links 11 turn about the support shaft 15. Additionally, a roller shaft 17 extends through elongated holes 16 at the rear upper parts of the driving links 11 so that a cam roller 18 is rotatably supported on the roller shaft 17. As the eccentric cam 10 is rotated by the driving shaft 8, it is brought in lose contact with the cam roller 18. The eccentric cam 10 ind the cam roller 18 are covered with a cam cover 19. Thus, the eccentric cam 10 operatively connected to the cam roller 18 via the cam cover 19. It should be noted that the roller shaft 17 is normally biased by the resilient power of a tension spring 20 so as to allow the roller shaft 17 to come in contact with the rear ends of the elongated holes 16.

Next, the foremost ends of the driving links 11 are connected to each other via a connecting shaft 21 transversely extending therebetween, and the connecting shaft 21 extends through projections 34 that forward of the magazine 2 (see FIG. 1). Incidentally, the range of the turning movement of the magazine 2 is defined between the position where the lower surface of the magazine 2, at the fore end of the latter, comes in contact with the stapling board 5 and the position where a pair of projections 22, projecting sideward of the magazine 2, are engaged with a pair of arc-shaped arms 23 standing upright from the base frame 1 on the opposite sides of the latter. A driver 32 is displaced in the upward or downward direction relative to the magazine 2, and the working stroke of the driving links 11 is set to be larger than that of the magazine 2. The rear ends of the driving links 11 are connected to each other via a connecting wall 11a transversely extending therebetween (see FIG. 5).

Incidentally, it is not necessary that the driving links 11 are connected directly to the driver 32. For example, the driving links 11 may operatively be connected to a holding member (not shown) adapted to hold the driver 32.

As the electric motor 3 is rotationally driven, the driving gear 9 drives shaft 8 and the eccentric cam 10. As shown in FIG. 3 and FIG. 4, as the eccentric cam 10 is rotated, the outer peripheral surface of the eccentric cam 10 comes in close contact with the outer peripheral surface of the cam roller 18 and this causes the cam roller 18 to move away from the driving shaft 8. Thus, the magazine 2 turns about the support shaft 15 in the downward direction. On the contrary, as the outer peripheral surface of the eccentric cam 10 is displaced away from the outer peripheral surface of the cam roller 18 to vary from the state shown in FIG. 3 to that shown in FIG. The cam roller 18 is pulled by the cam cover 19 to the driving shaft 8 and the magazine 2 turns about the support shaft 15 in the upward direction. Thus, the driving links 11 can be returned together with the magazine 2 without fail.

Since the driving links 11 are reciprocally turnably displaced to turn about the support shaft 15 in the above-described manner, the foremost end of the magazine 2, operatively connected to the foremost ends of the driving links 11, is turnably driven to turn about the support shaft 15 in the upward and downward directions. Since the turnable driving of the driving links 11 is achieved with the aid of the simple structure comprising the eccentric cam 10, the cam roller 18 and the cam cover 19, the whole structure of the magazine driving mechanism can be designed with small dimensions. Additionally, since the eccentric cam 10 and the cam roller 18 are arranged one after another along the center line of the driving links 11, the driving links 11 are always driven in synchronization with the magazine 2. Further, since return of the driving links 11 is achieved with the aid of the cam cover 19, it is not necessary that the resilient power of spring means is taken into account. This is in contrast with cases where the turnable displacement of the driving links 11 in the rearward direction is achieved with the aid of spring means. Thus, stable return of the driving links 11 can be realized with the aforementioned structure without fail.

However, any type of driving mechanism, e.g., a driving mechanism including a grooved cam may be employed in place of the aforementioned driving mechanism, provided that an output from the electric motor 3 can be converted into reciprocable turning movement of the driving links 11 about the support shaft 15.

Next, the structure of the magazine 2 and a staple forming or striking mechanism, for forming each straight staple by a forming plate 31 to exhibit a substantially inverted U-shaped contour and then striking a substantially inverted U-shaped staple by the driver 32, will be described below with reference to FIG. 5 to FIG. 7. As shown in the drawings, a staple cartridge fitting section 25 formed at the central part of a magazine housing 2a of the magazine 2 so as to allow a staple cartridge 4 to be fitted thereinto, and a staple forming/striking section 26 is formed on the downstream side of the staple cartridge fitting section 25. The rear end of the magazine housing 2a is turnably supported to turn about the support shaft 15 which transversely extends through the central upright standing pieces 1a on the base frame 1.

As shown in FIG. 7, a plurality of sheet-shaped staples 27 are received in the staple cartridge 4 in the multi-layered structure, and a pair of inwardly projected support projections 28 are formed along the lower ends of the side walls for holding the lower surface of the lowermost sheet-shaped staple 27a. The bottom of the staple cartridge 4 and the lower ends of both the side walls of the same are kept opened. A pair of inwardly projected guide walls 29 are formed on the inner wall surfaces of both the side walls of the magazine housing 2a for holding the lower surface of each sheet-shaped staple 27a taken out away from an opening portion formed at the lower end of a fore wall of the staple cartridge 4. As is best seen in FIG. 3, the bottom of the staple cartridge fitting section 25 is kept opened, and a staple feeding mechanism for feeding the lowermost sheet-shaped staple 27a among plurality of sheet-shaped staples 27 received in the staple cartridge 4 in the forward direction with the aid of the guide projections 29 is arranged below the bottom of the staple cartridge fitting section 25. As shown in FIG. 12, a cap 4b is placed on the upper end of the staple cartridge 4, and a coil spring is disposed between the cap 4b and the uppermost sheet-shaped staple 27 so as to normally depress the laminated sheet-shaped staples 27 in the downward direction.

As shown in FIG. 12, the staple cartridge 4 is composed of a cartridge housing 4a that has a plurality of sheet-shaped staples 27 received therein in the laminated state and a cap 4b placed on the cartridge housing 4a. An outfeed guide 107 is projected outward of a fore wall 106 of the cartridge housing 4a for successively delivering the sheet-shaped staples 27 via the outfeed guide 107, and four engagement projections 108 are formed on the opposite sides of the fore wall as well, as the rear wall of the cartridge housing 4a. A pair of inwardly projecting edges 28 are formed along the lower ends of both the side walls for holding the lower surface of the lowermost sheet-shaped staple 27 along the opposite side edges of the latter. The bottom of the cartridge housing 4a is kept opened with the exception of both the inwardly projected edges 28. An engagement piece 110 is formed at each corner of the cap 4b, and the engagement pieces 110 are brought in engagement with opening portions 111 formed through both the fore and rear walls of the cartridge housing 4a. A depressing plate 112 and a coil spring 113 are arranged between the cap 4b and the uppermost sheet-shaped staple 27 so that the laminated sheet-shaped staples 27 are normally forced in the downward direction by the resilient force of the coil spring L13.

Referring to FIG. 12 again, a staple cartridge fitting section 25 is formed at the central part of the magazine 2, a staple forming and striking section 26 is formed ahead of the staple cartridge fitting section 25. A staple feeding unit (not shown) for feeding each staple 27 received in the staple cartridge 4 to the forming and striking section 26, is arranged below the cartridge fitting section 25. The magazine 2 is dimensioned to have the same width as that of the staple cartridge. Side walls 2a stand upright on the opposite sides of the cartridge 4 while extending in parallel with each other, and substantially U-shaped cutouts 117, each kept opened in the upward direction, are formed at the central parts of both the side walls 2a corresponding to the geometrical configuration of the staple cartridge fitting section 25. In addition, recessed engagement portions 118, are adapted to receive the engagement projections 108 on the staple cartridge 4 and are formed at the upper open ends of the cutouts 117 on both the fore and rear sides of the latter.

When the staple cartridge 4 is fitted into the staple cartridge fitting section 25 of the magazine 2, as shown in FIG. 13, the staple cartridge 4 is first fitted into the cutouts 117. The engagement projections 108, on the cartridge housing 4a, are then brought in engagement with the recessed engagement portions 118 on the side walls 2a.

With the mechanism constructed in the above-described manner the turning movement of the magazine is stopped especially in the course of the turning movement of the same in the upward direction from below. At this time, the driver plate is actuated relative to the magazine in the upward direction. For example, the magazine is clogged with a staple due to incorrect stapling, there typically arises a malfunction such that the driver plate cannot be actuated in the magazine, and in an extreme case, the driver plate is integrally seized by the magazine. Since the magazine is forcibly raised up together with the driver plate in this case, a large force is exerted on the magazine, and stress is concentrated along the cutouts on the side walls of the cartridge. However, since the staple cartridge fitted into the staple cartridge is fitting section and is additionally fitted into the cutouts on the side walls a part of the load effective for bending the magazine can be borne by the staple cartridge. Consequently, there does not arise malfunctions that affect the rigidity of the magazine, and moreover, the magazine is no longer bent or broken when an excessively high intensity of force is applied to the magazine.

In addition, according to the present invention, a part of the magazine is cut out so that the foregoing part is utilized as a part of the staple cartridge fitting section, whereby the whole structure of the mechanism can be designed with small dimensions.

As shown in FIG. 6, a guide plate 30 is fixedly secured to the foremost end of the magazine 2, and a face plate 33 is disposed on the downstream side of the guide plate 30 while the forming plate 31 and the driver 32 are interposed between the guide plate 30 and the face plate 33.

The face plate 33 is disposed at the foremost end of the magazine 2 to slidably move in the upward and downward directions, while the driver 32 is disposed behind the face plate 33 to slidably move along the rear surface of the face plate 33 in upward and downward directions. A staple receiving portion 212 is formed at the lower part of the rear surface of the face plate 22 for receiving a substantially inverted U-shaped staple, and a projection 213 for raising up the face plate with users fingers is formed on the front side of the face plate 33. In addition, a pair of slit-shaped opening portions 36, each having a considerably large length as seen in the vertical direction, are formed through the face plate 33.

A pair of projection pieces 34 each extending in the forward direction and are formed by bending a part of the driver 32, while a projection piece 35 extending in the rearward direction is formed by likewise bending a part of the driver 32. When rear projection place 35 passes through an opening portion on the forming plate 31, while the fore projection pieces 34 pass through the opening portions 36 on the face plate 33 to project forward of the face-plate 33. As shown in FIG. 1, a connecting shaft 21 extends through the fore projection pieces 34 at a right angle relative to the magazine 2 to serves as connecting means for connecting the foremost ends of the driving links 11 to the magazine 2. Thus, the foremost end of the magazine 2 is operatively connected to the driving links 11 via the connecting shaft 21. As shown in FIG. 8, an anvil 37 is disposed below the forming plate 31, and a certain gap for enabling the driver 32 to slidably move therethrough in the downward direction is formed between the anvil 37 and the face plate 33. Thus, a staple 27 delivered in the forward direction with the aid of the staple feeding mechanism is caused to intermittently move between the forming plate 31 and the anvil 37.

As shown in FIG. 14(b), a pair of retaining portions 220 are adapted to be engaged with the upper end of the face plate 33 and to retain the latter which are formed at the upper end of the guide plate 30 while extending forward of the latter. A retaining piece 221, for releasing the face plate 33 from the retained state, is likewise formed at the upper end of the face plate 33 while extending rearward of the latter. As is best seen in FIG. 2, the retaining portions 220 and the retaining piece 221 are integrated with each other. As shown in FIG. 14(t), the retaining portion 220 is turnable in the arrow-marked direction by depressing the retaining piece 221 with a user's finger so that it is displaced away from the uppermost end of the face plate 33.

While the