GB2124960A - Punch for piercing sheet material - Google Patents

Abstract

A punch for piercing a thick bundle of sheets of paper comprises a gear mechanism 13,15 operationally associated with a handle 11 to move vertically a pair of paper holding plates 20 cooperating with a pair of cylindrical punches 2 provided on a base 1, thereby reducing the force required on the handle for the punching operation. The base plate 7, which has a pair of holes each defining a passage for one of the piercing blades, is pivotally mounted at 8 on the base 1, and is normally biased upwardly by a spring 10 to facilitate removal of the punches from the bundle of sheets of paper after it has been pierced. The punches and the paper holding plates are removably attached to the base and the gear mechanism, respectively, so that both of them can be easily changed to new ones if required. <IMAGE>

Description

SPECIFICATION Punch for piercing sheet material This invention relates to a punch for piercing sheet material such as paper, and more particularly to a large-sized punch for office use.

In a large punch for office use, a large force is required for operating its handle to make holes in a thick bundle of sheets of paper. It has been considered necessary to develop a punch which can be operated with a smaller force. It has also been found necessary to enable easy removal of piercing blades from a bundle of sheets of paper after it has been punched. Moreover, the piercing blades and the paper holding plate cooperating with the blades for punching operation become worn after a long time of use, and it is highly desirable to ensure that any worn blade or paper holding plate can be easily replaced by a new one.

According to the invention, there is provided a punch for piercing sheet material such as paper, comprising a pair of upstanding cylindrical piercing blades attached removably to a base adjacent to one end portion thereof, a base plate pivotally mounted at another end portion of said base for upwards and downwards movement, said base plate being upwardly biased and having a pair of holes each defining a passage for one of said blades, a vertically movable gear assembly provided adjacent to said one end portion of said base and engaged with gear means which are rotatable by means of a handle so that said gear assembly may be vertically moved when said handle is moved, and a pair of plates for holding the sheet material, said plates being attached removably to said gear assembly and each facing one of said blades, said holding plates being formed from a material which is lower in hardness than the cutting edge of said blades, but which is sufficiently hard to hold down the material to be pierced.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a perspective view of a punch embody ing this invention; Figure 1 is an exploded perspective view of the piercing blades and the paper holding plates in the punch shown in Figure 1; Figure 3 is a fragmentary side elevational view, partly in section, of the punch shown in Figure 1; Figure 4 is a fragmentary top plan view, partly in section of the punch shown in Figure 1, in which a handle is shown in its operative position; Figure 5 is an exploded perspective view of the base plate and the vertically movable gear in the punch shown in Figure 1; Figure 6 is an exploded perspective view showing a longitudinal paper positioning member;; Figure 7 is a fragmentary perspective view showing the underside of the base plate; Figure 8 is an exploded perspective view showing a transverse paper positioning member; and Figure 9 is a fragmentary side elevational view, partly in section, showing a modified combination of the vertically movable gear and the paper holding plates.

Referring first to Figures 1,3 and 4 of the drawings, there is shown a punch embodying this invention, and including a base 1 of the steel plate frame construction. A pair of cylindrical piercing blades 2 which are arranged upwardly are attached removably to the base 1 adjacent to one end thereof.

The blades 2 are supported on a blade mounting plate 3 adjacent to the opposite ends thereof, as shown in Figure 2. The mounting plate 3 has a pair of holes 4 in each of which a screw 5 (Figure 1 ) is fitted to secure the mounting plate 3 detachably to the base 1. A base plate 7 is provided on the base 1, and is mounted for rotation in a vertical plane by a pin 8 at the end of the base (remote from the blades 2).

The base plate 7 has a pair of holes 6 each defining a passage for one of the piercing blades 2.

An upstanding structural member 9 is integrally formed on the one end of the base 1. A spring 10 extends between one end of the base plate 7 and an inner wall portion of the upstanding structural member 9 to normally bias the base plate 7, especially the tip side of the base plate, upwardly, as shown in Figure 3. The member 9 is of the inverted L-shaped construction in side elevation. A handle 11 has lower ends attached rotatably to the top of the member 9, and as supported on a shaft 12 having a square cross-section.

A pair of gears 13 are provided on the shaft 12, and a vertically movable gear assembly 14 has a pair of racks 15 each engaged with one of the gears 13, as shown in Figures 3 and 4. Accordingly, if the handle 11 is tilted down, the gears 13 are rotated, and the racks 5 are, therefore, moved vertically to move the gear assembly 14 vertically. A tubular member 16 encircles the shaft 12 and is secured thereto by a screw rod 17. A coiled spring 18 encircles the tubular member 16, and has one end engaged with a portion of the top inner wall 19 of the u pstanding structural member 9 to urge the handle 11 in a counterclockwise direction in Figure 3, i.e., in the direction which causes upward movement of the vertically movable gear assembly 14.The gear assembly 14 is of the frame construction as shown in Figures 3 to 5, and carries a pair of paper holding plates 20 at its lower end.

The base plate 7 comprises a plate having a pair of downwardly bent longitudinal edge portions as shown in Figure 5, and is provided at one end thereof with an upstanding member 21 of inverted L-shaped construction in side elevation. The upstanding member 21 includes a horizontally projecting portion 22 which extends transversely of the base plate 7. The gear assembly 14 is formed adjacent to its bottom with a horizontal projection 23 above which the horizontally projecting portion 22 is positioned engageably therewith when the base plate 7 is in its uppermost position as shown in Figure 3.

The paper holding plates 20 are each a disc of a material of, for example, polyethylene, polypropylene and so on which is lower in hardness than the cutting edges of the piercing blades 2, but which is sufficiently hard to hold under pressure the paper to be pierced. Each disc 20 has a notched circumferential edge, and is formed in the centre of its upper surface with a projection 24 terminating in an upper end having an enlarged diameter, as shown in Figure 2.A disc mounting plate 25 is attached to the bottom of the vertically movable gear assembly 14, and has a pair of holes each formed by a hole segment 26a which enables passage of the projection 24 on one of the paper holding plates 20 when the paper holding plate is attached to the mounting plate 25, or removed therefrom, and another hole segment 26b having a smaller diameter than the hole segment 26a, and joined thereto for holding the projection 24 rotatably with its enlarged upper end resting on the peripheral edge of the hole segment 26b.

The punch also includes a longitudinal paper positioning mechanism 27 as shown in Figure 3. It defines the position of one end of the paper to be pierced. As shown in detail in Figure 6, the mechanism 27 comprises a movable plate 28 positioned on the underside of the base plate 7 adjacent to one end thereof, an upstanding stop member 30 secured to one end of the movable plate 28 by two rivets 29 extending through the base plate 7, and a shaft 31 extending transversely through the base plate 7 and the movable plate 28. The base plate 7 has a pair of elongated holes 7a in its downwardly bent longitudinal edge portions, and the movable plate 28 has a corresponding pair of holes 28a at the other end thereof. The shaft 31 extends through the holes 7a and 28a. The shaft 31 has an enlarged head as a stopper at one end, while a knob 32 is provided on the other end of the shaft 31.The base plate 7 has a pair of elongated holes 7b adjacent to one end thereof, as shown in Figures 3 and 5. The rivets 29 extend through the elongated holes 7b, and are movable therein, while the shaft 31 is movable in the elongated holes 7a, so that the integrated member of the movable plate 28 and the stop member 30 may be slidable longitudinally of the base plate 7. If it is necessary to change the distance between one end of the paper to be pierced, and the position at which a pair of holes are to be made in the paper, the knob 32 is moved to move the shaft 31 in the elongated holes 7a to thereby move the stop member 30 as required.

The punch also includes a transverse paper positioning mechanism 33 provided approximately in the midportion of the base plate 7. The base plate 7 has a pair of slots 7cformed in its downwardly bent longitudinal edge portions approximately in the mid-portion thereof, and a third slot 7dformed close to one of the slots 7c. A positioning strip 34 extends through the slots 7c, and is movable transversely of the base plate 7. A stop lever 35 has one end which projects through the slot 7d, and which is pressed down. One end of the positioning strip 34 is upwardly bent to define an edge support 36 for the paper to be pierced. The strip 34 has a plurality of spaced apart apertures 34a.The lever 35 is disposed behind one of the downwardly bent longitudinal edge portions of the base plate 7, and has another end secured thereto by a pin 40 about which the lever 35 is rotatable. The lever 35 has an upwardly directed projection 37 which is engageable in one of the apertures 34a of the strip 34 located above the lever 35, whereby the strip 34 is locked against movement. The positions of the apertures 34a are so selected that paper of various sizes, such as B4, A4, B5, A5 and B6, to be pierced may be accurately centred between the two piercing blades 2 when one longitudinal edge of the paper is held against the edge support 36. The mechanism 33 further includes a leaf spring 38 covering a portion of the strip 34, and secured to the underside of the base plate 7.The leaf spring 38 has at one end a pair of recesses 38a which define therebetween a hook projection 39 of appropriate strength engaged with a shoulder formed on the lever 35 to urge it upwardly so that the projection 37 thereof may be held in locking engagement with one of the apertures 34a in the positioning strip 34. If the lever 35 is pressed down, its projection 37 is disengaged from the strip 34 to render it movable.

The mechanism 33, thus, facilitates transverse positioning of the paper to be pierced, and is also useful for shifting the paper transversely when it is necessary to form more than two holes therein. In operation, the positioning strip 34 is appropriately moved to suit the paper to be pierced, while the longitudinal paper positioning mechanism 27 is also moved to suit the position at which the paper is pierced. A bundle of sheets of paper to be pierced is placed on the base plate 7, and one longitudinal or transverse edge thereof is held against the edge support 36, while one transverse or longitudinal edge thereof is held against the stop member 30.If the handle 11 is rotated clockwise in Figure 3, i.e., tilted down, the gears 13 are rotated to lower the vertically movable gear assembly 14to cause the paper holding plates 20 to press down the paper to be pierced, and the base plate 7 together, whereupon the piercing blades 2 are pierced through the paper. Small circular fragments or waste of paper, which are produced by the piercing operation, drop along the hollow interiors of the blades 2, and may be collected in a waste tray 44 disposed slidably in the base 1 as shown in Figure 3. Upon penetration of the blades 2 through the entire bundle of sheets to be pierced, their cutting edges abut on the paper holding plates 20. The surfaces of the plates 20, therefore, get worn or damaged after a long time of use of the punch. In such a case, the plates 20 may be slightly rotated to expose an unworn portion for abutment by the blades 2. The plates 20 are, therefore, eccentric to the blades 2. If the whole area of one surface of the plates 20 is worn, they can be reversed, and it their rear surfaces are totally worn, the plates 20 may be changed to new ones.

Referring now to Figure 9, there is shown a modified paper holding plate 41 supported on the vertically movable gear assembly 14 in a different way. The plate 41 is a disc of polyethylene, polypropylene, or the like having a hole 41a in its centre. A plurality of pins 42, which are formed from an elastic material, project downwardly from the bottom of the gear assembly 14, and are positioned to form a circle. The disc 41 is fitted about the pins 42, while a washer 43 is disposed between the assembly 14 and the disc 41.

As is apparent from the foregoing description, the handle and the vertically movable gear assembly operationally associated with the handle enable operation of the punch with a small force to pierce a thick bundle of sheets of paper. After the paper has been punched, it can easily be removed from the piercing blades, since the base plate is raised when the handle is raised. The punch has a long working life since a worn piercing blade or paper holding plate can be easily replaced by a new one.

Claims (6)

1. A punch for piercing sheet material such as paper, comprising a pair of upstanding cylindrical piercing blades attached movably to a base adjacent to one end portion thereof, a base plate pivotally mounted at another end portion of said base for upwards and downwards movement, said base plate being upwardly biased and having a pair of holes each defining a passage for one of said blades, a vertically movable gear assembly provided adjacent to said one end portion of said base and engaged with gear means which are rotatable by means of a handle so that said gear assembly may be vertically moved when said handle is moved, and a pair of plates for holding the sheet material, said blades being attached removably to said gear assembly and each facing one of said blades, said holding plates being formed from a material which is lower in hardness than the cutting edge of said blades, but which is sufficiently hard to hold down the material to be pierced.

2. A punch as claimed in claim 1, wherein each of said holding plates has an upwardly directed projection, and wherein said gear assembly is provided with a pair of holes each formed by a hole segment defining a passage for said projection on one of said holding plates, and another hole segment having a smaller diameter than said first mentioned hole segment, and joined thereto to hold said one holding plate rotatably.

3. A punch as claimed in claim 1, wherein each of said holding plates has a hole in its centre, and wherein said gear assembly is provided with a pair of sets of downwardly projecting pins formed from an elastic material, each of said holding plates being rotatably and removably fitted about one of said sets of pins which extend through said central hole.

4. A punch as claimed in any one of claims 1 to 3, further comprising a mechanism for defining the position of one transverse edge of the sheet material to be pierced, said mechanism being attached to said base plate and including a stop member against which said transverse edge of said paper is held, said stop member being movable toward or away from said blades.

5. A punch as claimed in claim 4, further comprising a mechanism for defining the position of one longitudinal edge of the sheet material to be pierced, said last mentioned mechanism being attached to said base plate and comprising a positioning strip extending transversely of said base plate, and bent upwardly at least at one end thereof, said strip having a plurality of apertures which are spaced apart from one another transversely of said base plate, and a lever provided below said strip, and having a projection which is normally biased by a leaf spring and engaged in one of said apertures, said lever being capable of lowered against the force of said spring to have said projection thereof disengaged from said one aperture to render said strip movable transversely of said base plate.

6. A punch substantially as hereinbefore described with reference to the accompanying drawings.