GB2032327A - Stapler drive and feed mechanisms - Google Patents

Abstract

The drive plate (6) of a stapler is drawn back from its normal position by a pivoting actuating lever (3), which pivots along a path such that it disengages from the drive plate at a certain point. The drive plate (6) is then thrown back towards its original position by a spring (8), forcefully ejecting from the stapler a staple put in the path of the drive plate. A spring biased head (17) pushes a staple to the drive plate (6) for being ejected. Upon return of the lever (3), it slides over the drive plate (6) until the lever is fully returned when it reengages the drive plate. <IMAGE>

Description

SPECIFICATION Stapler drive and feed mechanisms Background of the invention The present invention relates to staplers and more specifically to power staplers which throw the staples toward the surface to be stapled, so that the penetration of the surface is achieved by the kinetic energy imparted to the staples.

The invention specifically relates to the mechanism for building up the energy to drive the staple with the necessary force. The present invention also relates to the staple feed mechanism.

Summary of the invention It is the object of the present invention to provide a stapler with a simplified drive mechanism that is more reliable than conventional mechanisms.

It is a further object of the invention to provide a stapler with an improved feed mechanism that can be easily and quickly loaded and actuated and that will not come apart during loading.

The stapler of the invention is conventionally actuated by pressing together a grip and an articulated actuating lever. The staple drive plate of the stapler is mounted in the frame of the stapler in such a way that it can slide back and forth in the direction in which the staple is to be ejected and in the reverse direction. The drive plate is driven by a spring which normally seeks to eject a staple. The plate also has drive lever engaging means comprising an aperture to accommodate the actuating head of the drive lever.

Because the manually operable drive lever is pivotally mounted to the frame of the stapler, the actuating head of the drive lever follows a curved path, so that its motion draws the drive plate back from the staple, against the resistance of the storage spring, up to a certain angle at which the lever head slips out of the aperture of the plate, allowing the charged storage spring to drive the plate violently forward against the staple. The stroke of the plate is limited by the storage spring itself, which stops the plate in its original position.

The shifted drive lever is returned to its original position by a coil spring, which may be mounted to work either by extension or by compressiori. The drive lever is able to clear the drive plate as a result of being mounted on an articulation pin by means of orifices larger than necessary to accommodate the pin, permitting a slight translation ofthe lever with respect to the pin and the plate.

It follows from the foregoing that the drive mechanism is extremely simple and effective, and the risk of damage from use and rough handling being practically non-existent.

The staple feed mechanism of the stapler of the present invention has a staple-pushing part with a tongue which emerges to the exterior of the stapler through a longitudinal opening. The tongue allows the entrainment of the staple-pushing part to be effected against the action of a coil spring mounted on a bar which contitutesthe guide for the staplepushing part. This assembly is disposed against the body of the stapler at all times when the stapler is in use since it is connected pivotally to it at the end opposite the positioning end of the staple-pusher head.

The longitudinal opening in the frame of the stapler also permits a view at any time of the number of staples in the machine.

Brief description of the drawings Other objects and features of the stapler of the invention will be apparent from the following description and accompanying drawings in which: Figure 1 is a side view in cross section of the stapler of the present invention; Figure 2 is a side view in longitudinal cross section of the staple-pushing assembly of the stapler of Figure 1; Figure 3 is a top view of the staple-pushing assembly of Figure 2; Figure 4 is a front view of the assembly of Figures 2and3; Figure 5 is a cross section through the staplepushing head of the assembly of Figures 2-4 along the section line A-B of Figure 3; and Figure 6 shows a fragment of a different embodiment of the stapler of the present invention in a view corresponding to that of Figure 1, in which the lever recovery spring works in compression.

Detailed description of the preferred embodiments: The stapler of the invention includes a frame in which there is defined a stationary grip 1. An actuating lever 3 including an actuating head 2 inside the stapler frame 1. The lever 3 is mounted pivotally via the pin 4 on the frame 1. The actuating lever 3 extends to the exterior of the stapler and forms an angle with the grip 1.

The head 2 of the actuating lever 3 is provided with a reinforcement 5 at its working end, comprised of a considerably hardened material. The end 5 of the lever 3 acts on a drive plate 6 which is oriented tO shift left and right in Figure 1. The plate 6 is slidably mounted in a slot 6a in the frame. The purpose of the plate 6 is to supply to each staple (not shown) the blow necessary to drive it into the surface to be stapled.

The drive plate 6 has an aperture 7 in which the end 5 of the lever 3 is usually accommodated, as will be explained below. Upon being depressed toward the grip, the lever 3 rotates clockwise and draws the plate 6 to the right, toward pin 14, against the action of a torsion, storage spring 8, which is intended to store the tension sufficient for the subsequent driving of the plate 6. The middle of spring 8 is wrapped around and is supported by a pin 9 carried on the frame 1. The two ends of the spring 8 extend in opposite directions from the pin 9. One end 8a of the spring 8 rests against the body of the stapler itself while the other end 8b is applied against the drive plate 6 and is accommodated within an orifice 10 in the plate 6.

As the lever 3 is squeezed toward the grip 1 and the plate 6 is thereby moved toward pin 14, the tension of the spring 8 increases. Since the reinforce ment 5 of the lever 3 describes a curved path around pin 4, at a certain point in its path, when the lever 3 is almost to the grip 1, the end 5 is rotated free from the plate 6. The tensioned spring 8 now drives the plate 6 strongly to the left, against a staple (not shown) provided in the path of said drive plate 6 by the feed mechanism of the stapler, described below. The staple is fired out of the machine. The ejection movement of the plate 6 is stopped when the end 8b of the spring 8 is itself stopped by striking the abutment 11 of the stapler frame.

The return of the actuating lever3to its-original position is effected by means of a coil spring 12 which works in traction. One end of spring 12 is attached to a tongue 13 produced in one surface of the lever 3 to the opposite side of the articulation pin 4from the lever's actuating head 5. The other end of the spring -12 is attached to pin 14 in the corner of the frame of the stapler.

This actuating lever return structure can be replaced by that shown in Figure 6, in which the coil spring 12' works in compression, with one of its ends resting against the frame 1 of the stapler and with its other end resting against the actuating lever 3 between the actuating head 5 and the articulation pin 4. The spring 12' is fastened to the lever 3 with the aid of a stud 15 about which the spring 12' is securely wrapped.

In either case, during its recovery through swinging motion the lever 3 strikes the rearwardly facing surface of the drive plate 6. But the lever 3 clears the plate 6 due to the special elongated configuration of the orifices 16 in which the articulation pin 4 is located. The orifices 16 are lengthened in a direction generally perpendicular to the plate 6, so as to permit a slight displacement of the lever 3 with respect to the plate 6 sufficient to enable it to clear the edge of the plate 6 so that it may reach the aperture 7. Then the spring 7 again pulls the reinforcement end 5 into that aperture.

The feed mechanism is shown in detail in Figures 2-5.

The staple feed mechanism includes a bar 22 having a groove along the entire length of its upper surface. One end of bar 22 is provided with a pair of lugs 23, by which it is pivotally mounted in a bay defined by wall 20, by means of pin 24. A stapler pushing head 17 is slidably mounted on bar 22. It is urged toward the free end of the bar 22, i.e. away from lugs 23, by a coil spring 21 that is axially mounted on, e.g. by being wrapped around, the bar 22. The head 17, the cross-section of which is shown most clearly in FigureS, is preferably fitted around bar 22. The head 17 is made of an elastic material and is so shaped that it must be slightly deformed to house the bar 22 in it. Its elasticity prevents it from coming off the bar 22. It may also be kept from sliding off the end of the bar 22 by small teeth on the end of the bar 22. The underside of head 17 is provided with a tongue 18 that extends through slot 19 to the exterior of the stapler housing.

The traction exerted bythetongue 18 permits the displacement of the staple-pushing head 17 to the free end of the bar 22. In addition, opening 19 makes it possible at any time to view the number of staples present in the machine. The feed mechanism of the design is easy to assemble, requiring no complex mechanical operation. Moreover, it is especially reliable, depending for its proper functioning solely on the shape of its parts.

Although preferred embodiments of the invention have been described in detail, many modifications and variations of it will now be apparent to one skilled in the art, and accordingly the scope of the invention is to be limited not by the details of the embodiments described herein, but only by the appended claims,

Claims (16)

1. A stapler comprising: a frame; a drive plate slidably mounted in said frame for sliding between a first for ejecting a staple from said stapler, and a second position away from ejecting a staple; biasing means for urging said drive plate into said first position; actuating lever means swivelably mounted to said frame to move between a third and a fourth position corresponding, respectively, at said third position thereof, said lever means engaging said plate at said first position of said plate, said lever means remaining in engagement with said drive plate as said lever means moves to said fourth position thereof, and said lever means moves said plate to said second position thereof; said lever means being shaped and positioned to dis-engage from said drive plate upon said lever means reaching said fourth position when said drive plate reaches their said second positions, whereupon said drive plate upon reaching its said second position is returned to its said first position by said biasing means.

2. The stapler of Claim 1, wherein said biasing means is a spring which is increasingly charged as said plate moves to said second position.

3. The stapler of Claim 2, wherein said spring is a torsion spring including one end piece that engages said drive plate; and a support on said frame on which said spring is supported.

4. The stapler of Claim 1, wherein said actuating lever means is mounted rotatably to said frame, and said lever means engages said drive plate remotely from the pivot mounting thereof.

5. The stapler of Claim 4, further comprising returning means for returning said lever from its said second to its said first position.

6. The stapler of Claim 5, wherein said pivot mounting of said lever means comprises a pin on said frame and an aperture in said lever means which receives said pin; said aperture in said actuating lever being large enough to allow said actuating lever to translate in a direction generally toward and away from said drive plate a sufficient distance to allow said actuating lever to clear said drive plate in returning from said second to said first position of said lever.

7. The stapler of Claim 5, wherein said returning means comprises a spring having one end attached to said lever and one end attached to said frame.

8. The stapler of any of claims 5,6 or 7, wherein said returning means urges said actuating lever means toward said drive plate.

9. The stapler of Claim 7, wherein said spring returns said lever by exerting a pulling force thereon.

10. The stapler of Claim 7, wherein said spring returns said lever by exerting a pushing force thereon.

11. The stapler of Claim 3, wherein said spring serves to stop the motion of said drive plate in the direction from its said second to its said first position.

12. The stapler of Claims 1,2 or 4, further comprising means for feeding a staple into the path of said drive plate as said drive plate is moving to said first position for causing a staple to be expelled forcibly from said stapler; said feeding means comprising: a bar having one end mounted on said fram; a stapler pushing head mounted on said bar and slidable therealong; and means for urging said head away from said one end of said bar.

13. The stapler of Claim 12, wherein said head has on one side a tongue that at all times extends to the exterior of said stapler.

14. The stapler of Claim 13, wherein said head is made of an elastic material and has a recess in it accommodating said bar, said recess being small enough to require a slight deformation of said head to accommodate said bar.

15. The stapler of Claim 12, wherein said frame has an opening through which the number of staples in said stapler can be seen.

16. A stapler substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 5 of the accompanying drawings or as modified with Figure 6 of such drawings.