GB2463871A

GB2463871A - Power assisted stapler

Info

Publication number: GB2463871A
Application number: GB0817516A
Authority: GB
Inventors: David James
Original assignee: RAPESCO OFFICE PRODUCTS PLC
Current assignee: RAPESCO OFFICE PRODUCTS PLC
Priority date: 2008-09-24
Filing date: 2008-09-24
Publication date: 2010-03-31
Also published as: GB0817516D0

Abstract

A stapler 1 comprises a driving member for driving a staple from a magazine 55, an actuator, such as a handle 10, and a power spring 20 arranged to store energy applied to the actuator. A release member 30 is arranged to release the energy from the power spring to the driving member, such as a blade 5, where a portion 21 of the power spring is arranged to move with the actuator and to trigger the release member when the actuator reaches a predetermined position. Preferably, the power spring extends in a longitudinal direction, and the release member is moveable in a lateral direction to release a portion of the power spring (see figs 4b to 9b). A return spring 50 that acts on the power spring may be provided to return the stapler to an operable configuration after a staple has been driven.

Description

POWER-ASSISTED STAPLER

Field of the Invention

The present invention relates to a power-assisted stapler, particularly but not exclusively to a desktop power-assisted stapler.

Background of the Invention

Power-assisted staplers provide a strong staple driving force from a smaller user input force applied 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-A-5,356,063 discloses a power-assisted desktop stapler in which the power spring is connected directly to a push blade for driving staples out of the magazine. A pivotable latch engages with the push blade so as to lock the push blade while the handle is pushed down. The handle then releases the latch and the power spring drives the push blade so as to perform a stapling operation.

Patent publication EP-A-l 733 848 discloses a power-assisted desktop stapler using a more complex power spring mechanism, which is said to improve the stapling power such that additional manual operation is not necessary. However, the power spring mechanism is extremely complex and involves a great many moving parts.

The applicant's earlier patent publication WO-A-2007/107687 discloses a desktop power-assisted stapler, having a handle, a hammer for ejecting staples, and a driver 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 driver spring is compressed until a trigger is brought into contact with the link member, releasing the driver spring to drive the hammer and thus release a staple.

Hence, a large stapling force may be applied accurately and reliably, using a simple mechanism. An embodiment of this stapler has been launched commercially as the Rapesco X5TM stapler, and has enjoyed commercial success. However, there is a constant need to improve such staplers, particularly to simplify their mechanism.

Statements of the Invention

According to one aspect of the present invention, there is provided a stapler having a staple magazine, a driving member for driving a staple from the magazine, an actuator for application of a force to the stapler by a user, an energy storing element, arranged to store energy as force is applied to the stapler via the actuator, and a release member arranged to release the energy from the energy storing element to said driving member for driving the staple.

The energy storing element may comprise a power spring. The release member may comprise a support arranged to be moved so as to release the energy from the power spring when the actuator reaches a predetermined position as force is applied thereto.

The power spring may comprise a first part that moves with the actuator so as to contact and move the support when the actuator reaches the predetermined position. This arrangement simplifies the construction of the stapler, since the power spring itself is used to contact the support, rather than requiring a separate trigger portion as in the

prior art.

The power spring may comprise a second part that is supported by the support until the support is moved, whereupon the second part is released so as to release the energy of the power spring to the driving member. The driving member may be connected directly or indirectly to the second part. This arrangement simplifies the construction of the stapler, since the power spring may contact the support and/or the driving member directly, without requiring additional components therebetween.

The stapler may comprise return means arranged to bias the stapler to an operable position after a stapling operation has taken place. The return means may comprise a return spring. The return spring may contact the power spring directly, so as to reduce the number of components required for the stapling mechanism.

The support may be moveable laterally to release the energy from the power spring.

This lateral movement allows the support to move easily out of the way of longitudinally extending parts, such as the second part of the power spring, during the stapling operation. The lateral movement may comprise a pivoting movement.

S

According to another aspect of the present invention, there is provided a power-assisted stapler having a support member that engages a torsion spring on which a driving blade is mounted, and disengages the spring to release stored energy so as to drive the driving blade and perform a stapling operation. An arm of the torsion spring contacts the support member so as to disengage itself.

Brief Description of the Drawings

There now follows, by way of example only, a detailed description of a stapler in an embodiment of the invention, in which: Figure 1 is a schematic vertical longitudinal cross-section of the stapler with the handle in its rest position, with the staple magazine extended; Figure 2 is a schematic vertical longitudinal cross-section of the stapler with the handle in its rest position, with the staple magazine retracted; Figure 3 is a schematic vertical longitudinal cross-section of the stapler, as the user starts to push the handle down; Figure 4a is a schematic vertical longitudinal cross-section of the stapler, as the handle is pushed down further; Figure 4b is a cross-section through the plane A-A of Figure 4a; Figure Sa is a schematic vertical longitudinal cross-section of the stapler, as the user pushes the handle down yet further; Figure Sb is a cross-section through the plane A-A of Figure Sa; Figure 6a is a schematic vertical longitudinal cross-section of the stapler, as the user pushes the handle down yet further, just before the stapling action is triggered; Figure 6b is a cross-section through the plane A-A of Figure 6a; Figure 7a is a schematic vertical longitudinal cross-section of the stapler, after the stapling action is triggered; Figure 7b is a cross-section through the plane A-A of Figure 7a; Figure 8a is a schematic vertical longitudinal cross-section of the stapler, as the handle is allowed to rise after the stapling action is triggered; Figure 8b is a cross-section through the plane A-A of Figure 8a; Figure 9a is a schematic vertical longitudinal cross-section of the stapler, in which the handle has returned to its rest position; Figure 9b is a cross-section through the plane A-A of Figure 9a; Figure lOa is a schematic vertical longitudinal cross-section of the handle and driver spring; and Figure lOb is a top plan view of the handle and driver spring.

Detailed Description of the Embodiments

An embodiment of a stapler according to the present invention will now be described with reference to Figures 1 to 10; Figure 1 shows the stapler with staple magazine extended; Figures 2 to 9 show successive stages of the stapling action of the stapler; and Figure 10 shows the driver spring of the stapler in more detail.

The stapler 1 comprises abase 2, frame 3 and handle 10. The frame 3 and base 2 are connected by means of a base pin 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 handle pin 60.

An upper face of the base 2 is provided with a plate-like anvil 61, and the frame 3 is provided with a staple magazine 55. The magazine 55 is slidably mounted on a guide bar 57, fixed to the frame 3, and is biased by a magazine spring (not shown) to extend forward for loading, as shown in Figure 1. After loading, the magazine 55 is pushed by the user back into the frame 3, as shown in Figure 2, and is retained in position by a hook 67 that engages a notch 57 in the magazine 55. The hook 67 is rotatably mounted on a hook pin 65 and actuable by a hook lever 69, accessible by the user from the rear of the stapler I. The hook 67 is biased towards the magazine so as to be retained within the notch 57 until the hook lever 69 is actuated to release the magazine 55.

Staples are biased to the front end of the magazine 55, which has an opening 66 from which staples may be ejected by a driver blade 5 driven by a driver spring 20, which together comprise driving means for ejecting staples from the magazine 55. The driver blade 5 is supported above the staples in the rest position, allowing front-loading of the magazine without the need to rotate the handle 10 back to gain access to the magazine 55.

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 to perform a stapling operation, as illustrated in Figures 3 to 7. As will be described in greater detail hereinafter, this action results in a staple being pushed out from the magazine 55 with a strong ejection force by the mechanism of the stapler, as shown in Figure 7. The legs of the ejected staple pierce the loose items being stapled, and subsequently the tips of the staple legs contact the anvil 61. The upper surface of the anvil 61 may be provided with a contoured scoop such that the legs contacting the scoop are bent towards or away from each other, thus fastening the loose items together. The anvil 61 may be provided with a contoured scoop pair (not shown), which is rotatable by the user to determine whether the staple legs are bent towards or away from each other. Once the loose items have been stapled together, the handle 10 is released by the user to return to the rest position as shown in Figures 8 and 9.

The stapling mechanism of the stapler 1 will now be described in detail. The driver spring 20 comprises a torsion spring having an upper arm 21 and a lower arm 22, which extend from opposed ends of a spring coil 70 rotatably mounted on a frame pin 72. The angle between the upper arm 21 and the lower arm 22 is indicated as a, which is reduced as the driver spring 20 is compressed. The distal end 22a of the lower arm 22 extends through an aperture 5a in the driver blade 5, thereby engaging the driver blade 5 and applying a downward force thereto when the driver spring 20 is compressed. The distal end 21a of the upper arm 21 abuts the underside of the handle 10 and is prevented from lateral movement by means of a driver spring retaining portion 13, formed on the inner face of the handle 10. As best shown in Figure lOb, the upper arm 21 is formed with a hairpin bend at the distal end 21a, and the re-entrant portion of the upper arm 21 includes a generally downwardly depending portion 21b which abuts a return spring 50, in the form of a leaf spring mounted on the frame 3.

In this paragraph, particular directions are described with reference to Figures 4b, 5b, 6b, 7b, 8b and 9b. A support member 30 is pivotally mounted to the frame 3 about a substantially longitudinal axis of the stapler 1, by means of a support pin 31, and extends upwardly to one side of the lower arm 22. The support member 30 is biased towards a substantially upright position by a support spring 40, in the form of a coil spring compressed between the left side of the frame 3 and the left side of the support member 30. The support member has a lower arm 30a that projects rightwardly from the support pin 31 and abuts the bottom of the frame 3 when the support member 30 is in an upright position, to prevent the support member 30 pivoting past its upright position under the force of the support spring 40. The right side edge of the support member 30 includes a notch 30b that engages the lower arm 22 in the positions shown in Figures 1 to 6 and 9. The upper end 30c of the support member 30 has an upwardly angled surface arranged to be contacted by the upper arm 21 in the positions shown in Figures 5 to 7.

The operation of the stapler will now be explained. Figures 1 and 2 show the handle 10 and driver spring 20 when the stapler 1 is at rest. To staple items, a user presses down on the handle 10, which results in the driver spring 20 and return spring 50 being compressed and the frame 3 rotating downwardly about the base pin 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, as shown in Figure 4. The driver spring 20 is increasingly compressed by downward movement of the handle 10 and consequent downward movement of the upper arm 21, as shown in Figures 5 and 6. The lower arm 22 of the driver spring 20 is prevented from moving downwards by virtue of its engagement in the notch 30b of the support member 30, which is maintained in its upright position by the support spring 40, The driver blade 5 is also held above the magazine 55 by its engagement with the distal end 22a of the lower arm 22.

S

As the handle 10 is pushed further towards the base 2, the driver spring 20 is compressed further, such that an increasing downward force is applied to the lower arm 21, which is opposed by the upright support member 30. At the position shown in Figure 5, the upper arm 21 comes into contact with the upper end 30c of the support member and begins to pivot the support member 30 sideways against the bias of the support spring 40, away from the lower arm 22, as shown in Figure 6. At that point, only a minimal amount of additional downward force on the handle 10 is required to pivot the support member 30 out of engagement with the lower arm 22. The energy stored in the driver spring 20 is then rapidly released, driving the lower arm 22 and hence the driver blade 5 downwards, causing the driver blade 5 to forcibly eject a staple from the opening 66 at the front of the magazine 55, in the position shown in Figure 7.

The ejected staple then pierces and fastens together the items to be stapled, with a large and substantially constant force for each stapling operation. As the upper arm 21 releases the support member 30 when the handle 10 is in a predetermined position, the amount of energy released by the driver spring 20 is substantially constant. Thus, staples will be reliably ejected from the stapler 1 with the same stapling force.

When the items have been stapled, the user releases the handle 10, which then moves upwardly, away from the base 2, under the action of the return spring 50. As the handle moves upwardly, the upper arm 21 of the driver spring 20 moves upwardly also, and returns to the position shown in Figure 9, which is the same as that shown in Figures 1 and 2. The lower arm 22 rides up the side of the support member 30, under the force of the return spring 50, until the lower arm 22 engages once again in the notch 30b.

The stapling mechanism described above is greatly simplified relative to the power stapling mechanisms of the prior art. In particular, the main driving components comprise only the frame 3, the handle 10, the power spring 20, the support 30 and the blade 5. There is no need for a hammer connected to the blade 5, for example as described in WO-A-2007/107687, nor the complex lever mechanism disclosed in EP-A- 1 733 848, because the power spring contacts the support 30 and the driver blade 5 directly. There is no need for a trigger member attached to the handle 10, because the spring 20 itself acts on the support 30.

Moreover, lateral movement allows the support 30 to release and move out of the way of the power spring 20 with a relatively small degree of movement, and a very simple mechanism.

Alternative or additional features are envisaged within the scope of the invention. For example, the support member 30 may be slidable rather than pivotable in the frame 3, and various other shapes and configurations of the support member 30 are possible. The support member 30 is preferably a unitary member, but may comprise a two-part pivoting link mechanism, with the upper link permanently connected to the lower arm 22 and the lower link connected to the support pin 31.

In the embodiment above, the handle 10 does not directly contact the driver blade 5, such that additional force cannot be applied to the driver blade 5 after the power spring has been released. Alternatively, the driver blade 5 may extend upwardly so that the handle 10 may contact the driver blade directly and apply additional force thereto after the power spring has been released.

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

IClaims I. A stapler having a staple magazine, a driving member for driving a staple from the magazine, an actuator for application of a force to the stapler by a user, a power spring arranged to store energy as force is applied to the stapler via the actuator, and a release member arranged to release the energy from the power spring to said driving member for driving the staple; wherein a portion of the power spring is arranged to move with the actuator and to trigger the release member when the actuator reaches a predetermined position.
2. The stapler of claim 1, wherein the power spring comprises a torsion spring and said portion comprises a first arm of the torsion spring.
3. The stapler of claim 2, wherein the release member is arranged to support a second arm of the torsion spring such that the power spring is compressed as force is applied to the actuator, and to release the second arm when triggered, the second arm being connected to the driving member.
4. The stapler of claim 3, wherein the driving member is mounted on an end of the second arm.
5. The stapler of claim 3 or 4, wherein the release member is moveable laterally so as to release the second arm.
6. A stapler having a staple magazine, a driving member for driving a staple from the magazine, an actuator for application of a force to the stapler by a user, a power spring arranged to store energy as force is applied to the stapler via the actuator, and a release member arranged to release the energy from the power spring to said driving member for driving the staple; wherein a portion of the power spring extends in a substantially longitudinal direction relative to the stapler, and the release member is moveable in a substantially lateral direction to release said portion of the power spring.
7. The stapler of claim 6, wherein the release member is pivotally mounted so as to move in said lateral direction.S
8. The stapler of claim 6 or claim 7, wherein the release member includes a lateral recess for retaining said portion of the power spring.
9. A stapler having a staple magazine, a driving member for driving a staple from the magazine, an actuator for application of a force to the stapler by a user, a power spring arranged to store energy as force is applied to the stapler via the actuator, and to release the energy from the power spring to said driving member for driving the staple; and a return spring arranged to return the stapler to an operable configuration after the staple has been driven, wherein the return spring is arranged to act on the power spring.
10. A stapler substantially as herein described with reference to and/or as shown in the accompanying drawings.