WO2007107687A1

WO2007107687A1 - Stapler

Info

Publication number: WO2007107687A1
Application number: PCT/GB2006/004671
Authority: WO
Inventors: Yoshiyuki Ebihara
Original assignee: Rapesco Office Products Plc.
Priority date: 2006-03-17
Filing date: 2006-12-14
Publication date: 2007-09-27
Also published as: GB0605471D0; CA2645866A1; GB2436081A; TW200800521A; CN101466502A

Abstract

A stapler (1) has a handle (10), a hammer (9) for ejecting staples, and a hammer spring (20) for driving the hammer when released. The hammer (9) is prevented by a link member (30), held in place by a spring (40). As the handle (1) is depressed, the hammer spring (20) is compressed until a trigger (12) is brought into contact with the link member (3), releasing the hammer spring (20) and driving the hammer to release a staple. Hence, a large stapling force may be applied accurately and reliably.

Description

STAPLER

Field of the Invention

The present invention relates to a stapler.

Background of the Invention

"Power-assisted" staplers are known, which provide a strong staple driving force from a smaller user input force made to the stapler. Typically, "power-assisted" staplers use a power spring which stores energy as a result of a handle of the stapler being actuated by a user. The stored energy is then released to drive staples from the stapler. Patent publication US 6 145 728 applies the so-called "tucker" construction to a stapler. Staples are ejected from the stapler with a strong force by means of the stapler mechanism, which involves the simultaneous lifting of a plunger by a pivoting lever and compression of a power spring. After the plunger has been lifted a certain distance, the pivoting lever arm slips out of engagement with the plunger, which then descends rapidly under the action of the power spring so as to eject a staple from the stapler. The mechanism is not always reliable, however, and there is a risk that staples might be forced out of the stapler unexpectedly if the lever disengages from the plunger prematurely. Although attempts have been made to improve on the design to avoid this risk, these have resulted in complicated stapler structures. Furthermore, the points of the plunger which receive the lever can suffer from wear, owing to the large amounts of friction which are created when the lever slips out of engagement with the plunger.

A different problem encountered with typical "desk-top" staplers is that to replace staples, a user must turn and open the base and frame of the stapler over a wide angle, which is a cumbersome operation. Statement of the Invention

According to the present invention, there is provided a stapler comprising: (a) an actuator for application of a force to the stapler by a user; (b) a staple ejector, movable from a first position to a second position to eject a staple from the stapler;

(c) an energy storing element, arranged to store energy as force is applied to the stapler via the actuator, and to release said energy by moving the staple ejector from the first position to the second position; and (d) a resistive element, movable between a first condition in which it maintains the staple ejector in the first position as the force is applied via the actuator, and a second condition in which it permits the staple ejector to move to the second position under the action of the energy storing element.

Embodiments of staplers according to the present invention may provide a reliably actuated staple driving power, as the staple ejector is held in place in the first position until the resistive element moves into the second condition. Embodiments may be made of a small number of parts and be of simple construction. In particular, the resistive element used to block movement of the staple ejector during a stapling operation may be a simple structure. Hence, the manufacturing of embodiments of the present invention may be simplified and the associated costs reduced, in addition to the reliability of the stapler being increased.

In one embodiment, a stapler has a handle, a hammer for ejecting staples, and a hammer spring for driving the hammer when released. The hammer is prevented from descending by a link member, which is held in place by a spring. As the handle is depressed, the hammer spring is compressed until a trigger is brought into contact with the link member, releasing the hammer spring to drive the hammer and thus release a staple. Hence, a large stapling force may be applied accurately and reliably.

Brief Description of the Drawings There now follows, by way of example only, a detailed description of preferred embodiments of the present invention in which:

Figure 1 is an external side elevation view of a first embodiment of a stapler according to the present invention, at rest;

Figure 2 is an external view of the stapler of Figure 1 during a stapling operation;

Figure 3 is a cross-sectional view of the stapler of Figure 1 in an "at rest" condition; Figure 4 is an exploded perspective view of part of the stapler of Figure 1 ;

Figure 5 is a top view of a hammer of the stapler of Figure 1 ; Figure 6 is a side view showing parts of the stapler of Figure 1 in more detail; Figure 7 is a front view of a link member of the stapler of Figure 1; Figure 8 is a cross-sectional top view of the inner structure of the stapler of Figure 1;

Figure 9 is a cross-section though the inner structure of the stapler of Figure 1; Figures 10 to 14 are cross-sectional views showing the inner structure of the stapler of Figure 1 during a stapling operation;

Figure 15 shows the stapler of Figure 1 with a magazine of the stapler extended from the stapler;

Figure 16 is a cross-sectional view showing the inner structure of a stapler according to a second embodiment of the present invention at rest, omitting views of a link spring and hammer spring for clarity; and

Figure 17 is a cross-sectional view showing the stapler of Figure 16 during a stapling operation.

Detailed Description of the Embodiments

A first embodiment of a stapler according to the present invention will now be described with reference to Figures 1 to 15. Figures 1 and 2 illustrate the first embodiment at rest and in use, respectively. As shown in Figure 1, the first embodiment of a stapler 1 comprises a base 2, frame 3 and handle 10. The frame 3 and base 2 are connected by means of a frame base shaft 59, such that the frame 3 may pivot relative to the base 2. Similarly, the handle 10 is pivotally mounted to the frame 3 by means of a frame handle shaft 60. An upper face of the base 2 is provided with a plate-like anvil 61, and the frame 3 is provided with a magazine 55 which can be loaded with staples.

Items to be stapled together, such as loose sheets of paper, are inserted into the gap between the anvil 61 and the magazine 55 at the front of the stapler 1, and the handle 10 is pushed downwardly by a user towards the base 2, as illustrated in Figure 2. As will be described in greater detail hereinafter, this results in a staple being pushed out from the magazine 55 with a strong ejection force by the mechanism of the stapler. Legs of the ejected staple pierce the loose items being stapled, and subsequently tips of the staple legs contact the anvil 61. The upper surface of the anvil 61 is provided with a contoured scoop (not shown) such that the legs contacting the scoop are bent towards each other, thus closing the staple and fastening the loose items together. The anvil 61 is also provided with a contoured scoop pair (not shown), which cause the staple legs to be moved apart, rather than together, to secure the loose items. Whether the staple legs are brought into contact with the contoured scoop or the contoured scoop pair is determined by the user, who may rotate the anvil 61 relative to the base 2 to position the scoop or scooped pair appropriately. Once the loose items have been stapled together, the handle 10 is released by the user to return to the "at rest" condition shown in Figure 1 , as described in greater detail later.

The inner structure of the stapler 1 will now be described with reference to Figures 3 to 9. As indicated above, the handle 10 is pivotally mounted to the frame 3 by means of a frame handle shaft 60. The handle 10 itself comprises two downwardly- depending sidewalls 62 linked by a joining wall 63, which is angled upwardly relative to the base 2. As seen from Figure 3, the internal surface of the joining wall 63 is provided with a downwardly-depending trigger 12, the purpose of which will become clear further on, and a hammer spring holder 13, in the form of a rounded protrusion. A handle spring 50 is connected to the frame 3 by means of a shaft 51. The handle spring 50 comprises an upper arm 64 and a lower ami 65 which extend from opposed ends of a coil 66 of the hammer spring 50. The lower arm 64 contacts an abutment on the frame 3. The upper arm 64 contacts the internal surface of the joining wall 63, and biases the handle 10 upwardly, away from the base 3.

A lower portion of the frame 3 is provided with an elongate magazine 55 for staples. The magazine 55 is slidably mounted on the frame 3, and the front end of the magazine 55 has an opening 66 from which staples may be ejected.

The frame 3 is also provided with a hammer 9, which is located on the frame 3 above and towards the front of the magazine 55. The hammer 9 is pivotally mounted to the frame 3 by means of a hammer frame pin 25, as described in greater detail below.

The hammer 9 itself is shown in more detail in Figures 4 and 5. The hammer comprises a frame formed of two substantially "L"-shaped side walls 67, which are joined together by a horizontal bottom wall 4 and a vertical end wall 68 provided at the front of the hammer 9. Each of the side walls 67 is provided with a pair of holes 7, 8; each hole of each side wall 67 is positioned so as to be in alignment with the corresponding hole formed in the other side wall. Each side wall 67 is also provided with a hammer spring stopper 6 in the form of a horizontal plate, disposed at the top of each side wall 67 at the rear of the hammer 9. At the front of the hammer 9, a blade mounting protrusion 5 projects forwardly from the vertical end wall 68. The cross- section of this protrusion 5 is such that a blade 45 may be mounted on the protrusion 5, by inserting the protrusion 5 through a correspondingly-shaped hole 69 formed in the blade. As will become clear, the hammer 9 and the blade 45 comprise a staple ejector for ejecting staples from the magazine 55.

As shown in Figure 5, the bottom wall 4 of the hammer 9 is provided with a central rectangular opening 16. The width of this opening 16 is narrowed towards the front of the hammer 9 by link stopper portions 15 formed on the bottom wall 4. As shown in Figure 3, the hammer 9 is pivotally mounted to the frame 3 by means of a hammer frame pin 25, which protrudes through the aligned rear-most holes S of the hammer side walls 67 and projects into receiving portions (not shown) formed in the frame 3. The hammer frame pin 25 also protrudes through, and thus provides a mounting for, the coil 70 of a hammer spring 20, which is located in the region between the hammer side walls 67 at the rear end of the hammer 9. The hammer spring 20 comprises an upper arm 21 and a lower arm 22, which extend from opposed ends of the hammer spring coil 70. The extent of upward movement of the upper arm 21 is restricted by the hammer spring stopper 6 of the adjacent hammer side wall 67. The lower arm 22 of the hammer spring 20 lies on the bottom wall 4 of the hammer. When the hammer 9 is mounted to the frame 3, as shown in Figure 3, an upper side of the upper arm 21 contacts the hammer spring holder 13, formed on the inner face of the

^■ handle 10. In this "at rest" condition, the angle between the upper and lower arms of the hammer spring 20 is α°.

Also connected to the hammer 9 is a link member 30, which protrudes through the opening 16 formed in the bottom wall 4 of the hammer 9. As illustrated in Figure 4, the link member 30 comprises an upper member 31 and a pair of lower members 32. The upper member 31 is in the form of a plate having a trigger receiving portion 36 protruding forwardly of the upper member 31 at its lower end. The upper member 31 is pivotally connected, at its lower end, to each of the plate-like lower members 32 by a connection pin 33.

The link member 30 is pivotally mounted to the hammer 9 by mounting pins

34, which project from either side of the upper end of the upper member 31 and protrude through the foremost aligned holes 7 of the hammer side walls 67. Similarly, the lower members 32 are pivotally mounted to the frame 3 by means of mounting pins

35, which project outwardly from lower ends of the lower members 32 and are received in holes (not shown) formed in the frame 3. Thus, it is to be understood that the link member 30 is connected between the hammer 9 and the frame 3. A link spring 40 is mounted to the frame by means of a shaft 41. The link spring 40 comprises a lower arm 71 and an upper arm 72 extending from opposed ends of a link spring coil 73. The lower arm 71 contacts an abutment provided on the frame 3, and the upper arm 72 of the link spring 40 contacts an upper portion of a rear face of one of the lower members 32 of the link member 30. The link spring 40 thus provides a bias which acts to push the link member 30, and in particular the connection pin 33, in a forward direction, i.e. in a direction towards the front of the stapler 1. As a result of this bias, front faces 37 of the lower members 32 are brought into contact with the link stopper portions 15 formed on the bottom wall 4 of the hammer 9 when the stapler 1 is at rest, as illustrated in Figure 6. Thus, when the stapler 1 is at rest, the link member 30 is maintained in an upright position, with the axes of the connection pin 33 and mounting pins 34, 35 lying substantially in the same plane.

The operation of the first embodiment will now be explained, with reference to Figures 9 to 14. Figure 9 shows the frame 3, magazine 55 and hammer 9 of the stapler 1 when the stapler 1 is at rest. To staple items, a user presses down on the handle 10, which results in the handle spring 50 being compressed and the frame 3 rotating downwardly about the frame base shaft 59, such that the items to be stapled become trapped between the anvil 61 of the base 2 and the forward end of the magazine 55. In addition to compression of the handle spring 50, the hammer spring 20 is also increasingly compressed by downward movement of the handle 10. The upper arm of the hammer spring 20 is prevented from moving upwards to release this compression owing to its contact with the hammer spring holder 13. The lower arm 22 of the hammer spring therefore applies a generally downwardly-directed force, substantially parallel to the plane in which the axes of the connection pin 33 and mounting pins 34, 35 lie, to the bottom wall 4 of the hammer 9. Despite the application of this force to the hammer, however, the hammer 9 is prevented from moving downwardly towards the base and frame 3 by the upright link member 30, which is connected between the hammer and the frame. The link member is maintained in its upright position by the link spring 40 and link stopper portions 15 of the hammer 9, which resist lateral movement of the connection pin 33. As the handle 10 is pushed further towards the base 2, the hammer spring 20 is compressed further, such that an increasing downward force is applied to the hammer 9, which is opposed by the upright link member 30. Eventually, at a predetermined position of the handle 10, the trigger 12 is brought into contact with the trigger receiving portion 36 of the upper member of the link member 30, as shown in Figure 10. At that point, only a minimal amount of additional downward force on the handle 10, moving the handle beyond the predetermined position, is required to push the connection pin 33 rearward, out of the plane in which the mounting pins 34, 35 lie, against the bias of the link spring 40. When this occurs, the link member 30 can no longer sustain the downward force being applied on the hammer 9 by the hammer spring 20, and the link member 30 collapses into a reversed L-shape as the front of the hammer 9 rapidly descends under the action of the compressed hammer spring 20. As may be seen from Figures 11 and 12, which show sequential stages in the stapling process, the rapid descent of the hammer 9 causes the blade 45 installed on the front of the hammer 9 to forcibly eject a staple from the opening 66 at the front of the magazine 55. The ejected staple then pierces and fastens together the items to be stapled, as described with reference to Figure 2 above.

Thus, moving the handle 10 downwardly causes continued compression of the hammer spring 20, until a trigger point is reached at which the trigger 12 contacts the trigger receiving portion 36 of the link member 30. A small further downward movement of the handle 10 then results in rearward movement of the connection pin 33.

This, in turn, results in the simultaneous descent of the hammer 9, under the action of the compressed hammer spring 20, and collapse of the link member 30, and subsequent staple ejection.

As the trigger 12 contacts the trigger receiving portion 36 when the handle 10 is in a predetermined position, it is thus to be understood that the amount of energy stored in the hammer spring 29 at the time that the hammer 9 is released may also be predetermined, as the hammer spring will have undergone a given amount of compression once the trigger point is reached. Thus, staples will be reliably ejected from the stapler 1 with the same stapling force. When the items have been stapled, the user simply removes their hand from the handle 10 to release the downward force on the stapler. The handle 10 then moves upwardly, away from the base 2, under the action of the compressed handle spring 50. As the handle moves upwardly, the upper arm 21 of the hammer spring 20 moves upwardly also, and in so doing reaches the position shown in Figure 13. In the position of Figure 13, the upper arm 21 of the hammer spring 20 contacts an adjacent hammer spring stopper 6, and the angle subsumed by the upper arm 21 and lower arm 22 of the hammer spring 20 is again α°. This angle of separation is maintained until the handle 10 returns to its pre-stapling position, indicated "A" in Figure 14.

As indicated in Figure 13, the link spring 40 applies a continual forward bias to the link member 30. This causes the link stopper portions 15 to ride up the inclined front faces of the lower members 32 of the link member 30, resulting in the simultaneous raising of the hammer 9 and alignment into the same vertical plane of the axes of the connection pin 33 and mounting pins 34, 35, until the hammer 9 and link member 30 are restored to the configuration illustrated in Figure 3. It will be appreciated, therefore, that the stapler 1 simply and automatically reverts to its "at rest" condition once downward pressure is removed from the handle 10.

As shown in Figure 15, the sliding mounting of the magazine 55 enables the magazine 55 to be pulled forwardly of the frame 3 to replace ejected staples. This functionality is enabled by the fact that the stapler 1 uses a resistive element, in the form of a link member 30, to block the descent of the hammer 9 and blade 45 until the block is released, rather than using a blade 45 mounted on the front of the magazine 55. Thus, the magazine 55 can be pulled forwardly to exchange staples, meaning that the replacement of staples is simple and convenient, and does not require relative rotation of the base and frame.

Figures 16 and 17 show a second embodiment of the invention, wherein the same staple ejection mechanism as described above with reference to the first embodiment is applied to a more compact stapler. As the configuration of the stapler mechanism is the same, like parts are indicated by like numerals and further description thereof is not given here.

The embodiments described above are illustrative of rather than limiting to the present invention. Alternative embodiments apparent on reading the above description may nevertheless fall within the scope of the invention.

Claims

C L A I M S

1. A stapler comprising:

(a) an actuator for application of a force to the stapler by a user;

(b) a staple ejector, movable from a first position to a second position to eject a staple from the stapler;

(c) an energy storing element, arranged to store energy as force is applied to the stapler via the actuator, and to release said energy by moving the staple ejector from the first position to the second position; and

(d) a resistive element, movable between a first condition in which it maintains the staple ejector in the first position as the force is applied via the actuator, and a second condition in which it permits the staple ejector to move to the second position under the action of the energy storing element.

2. A stapler according to claim 1, wherein said resistive element is connected between the staple ejector and another part of the stapler relative to which the staple ejector is movable.

3. A stapler according to claim 2, wherein said resistive element has a rotatable connection to at least one of the staple ejector and said another part of the stapler.

4. A stapler according to claim 3, wherein the resistive element is rotatably connected to the staple ejector about a first axis of rotation and is rotatably connected to said another part of the stapler about a second axis of rotation.

5. A stapler according to claim 4, wherein the resistive element comprises first and second elements, rotatably connected to each other about a third axis of rotation.

6. A stapler according to claim 5, wherein the resistive element is arranged such that the first, second and third axes of rotation all lie in substantially the same plane when the resistive element is in the first condition, and wherein the energy storing element applies a force, having a component parallel to the plane, to the staple ejector when a force is applied to the stapler via the actuator.

7. A stapler according to claim 6, wherein the stapler further comprises an alignment element which acts to maintain the first, second and third axes of rotation in substantially the same plane.

8. A stapler according to claim 7, wherein the alignment element comprises a deformable, resilient element.

9. A stapler according to any one of claims 2 to 8, wherein said another part of the stapler is a frame to which the staple ejector is movably mounted.

10. A stapler according to claim 9, wherein said staple ejector is pivotally mounted to said frame.

11. A stapler according to claim 9 or 10, wherein the stapler further comprises a staple magazine mounted to said frame.

12. A stapler according to claim 11 , wherein said staple magazine is slidably mounted to said frame.

13. A stapler according to claim 11 or 12, wherein at least part of the staple ejector is arranged to enter the staple magazine to eject a staple therefrom.

14. A stapler according to claim 13, wherein the staple ejector comprises a blade which is arranged to enter the staple magazine to eject a staple therefrom.

15. A stapler according to any preceding claim, wherein said resistive element protrudes through an aperture formed in the staple ejector.

16. A stapler according to claim 15, wherein said resistive element abuts at least a portion of a perimeter defining said aperture when said resistive element is in the first condition.

17. A stapler according to any preceding claim, wherein said resistive element is movable between the first and second conditions by means of a trigger element.

18. A stapler according to claim 17, wherein said trigger element is connected to the force actuator so as to cause the resistive element to move to the second condition when the force actuator is moved beyond a predetermined position.

19. A stapler according to any preceding claim, wherein said energy storing element comprises a deformable, resilient element.

20. A stapler according to any preceding claim, wherein said stapler further comprises a restoring element arranged to restore at least part of the stapler to a pre- stapling state after a stapling operation has been completed.

21. A stapler according to claim 20, wherein said restoring element contacts said force actuator so as to restore the force actuator to its pre-stapling state.

22. A stapler according to claim 20 or 21, wherein said restoring element comprises a deformable, resilient element.