Paper Punch With Variable Spacing

The present invention relates to paper punches and particularly to punches which provide for selection of different spacings between the holes punched. While reference is herein made to punching paper, it will be understood that the punch is equally applicable to punching plastic or other sheet material.

Paper punches are widely used for punching holes in paper to be used in ring binders or with various fastening devices used in assembling loose-leaf books or office files. As different numbers of holes and different hole spacing are required for different applications, punches have been provided with a plurality of spaced holes adapted to receive individual punching elements which are removable and interchangeable. By selecting the desired number of punching elements and placing them in suitably spaced holes of the punching device the desired number and spacing of holes can be punched in the paper.

While multiple punching devices of this kind are in general satisfactory, they have been found to be subject to various deficiencies and disadvantages. One difficulty has been in retaining the removable punching elements in the punch in such manner that they will not fall out when the punch is inverted but at the same time can be readily inserted and removed when desired. Another problem that has become more aggravated with increased material and manufacturing costs is that punches of this kind have become expensive to manufacture and hence must be sold at a high price.

It is an object of the present invention to overcome the deficiencies and disadvantages of prior art punches and to provide an improved variable spacing paper punch. In accordance with the invention, the punch comprises a frame, a cooperative base supporting the frame, a plurality of individual punches removably and changeably mounted in the frame and an operating handle for actuating the punches. The frame comprises a single sheet of metal which is bent to form a punch holding section of U-cross section comprising an upper portion, a lower portion and a portion connecting the upper and lower portions and a die section which is joined with the lower portion of the punch holding section by a fold line and underlies the lower portion with an intervening space to receive the material to be punched. The upper and lower portions of the punch holding section have aligned bearing holes to receive and guide the punches while the die section has punching holes aligned with the bearing holes and adapted to receive the lower ends of the punches when actuated by the operating handle. The base is formed of resilient plastic material and comprises a first section which closes the open side of the punch holding section of the frame, a second section which supports the frame and a third section which underlies the die section of the frame and provides a container for receiving punchings. The first and second sections of the base are joined by a fold line of reduced thickness to facilitate bending the first section up to a position for closing the open side of the punch holding section of the frame while the second and third sections of the base are joined by a hinge line of reduced thickness to permit the third section to swing downwardly so as to open the container and permit emptying the punchings therefrom. A further feature of the invention is that flexible edge portions of the first section of the base engage in annular recesses provided in the individual punches so as to retain them removably in the frame while permitting easy insertion and withdrawal of the punches when it is desired to change the spacing or number of the holes to be punched.

The nature objects and advantages of the invention will be more fully understood from the following description of a preferred embodiment illustrated by way of example in the accompanying drawings in which:

FIG. 1 is a front elevation of a preferred embodiment of a punch in accordance with the invention.

FIG. 2 is a plan view with the operating handle removed.

FIG. 3 is a plan view of the base.

FIG. 4 is an end view of the punching device.

FIG. 5 is a cross section taken approximately on the line 5--5 in FIG. 1 but on a larger scale.

FIG. 6 is a fragmentary plan view of the base with one punch shown in section to illustrate a modification and

FIG. 7 is a partial cross section taken approximately on the line 7--7 in FIG. 6.

The punching device shown by way of example in the drawings comprises a frame 1, a plurality of punch assemblies 2, an operating handle 3 and a base 4. The frame 1 comprises a single sheet of metal which is shaped to form a punch holding section 11 and a die section 12. The punch holding section 11 is U-shaped in cross section with an upper portion 11a, a lower portion 11b and a connecting portion 11c. As seen in FIG. 5 the upper portion 11a is approximately parallel to the lower portion 11b but is narrower. The connecting portion 11c is at the front of the punching device, the rear side of the punch holding section 11 of the frame being open. The bend line 13 between the upper portion 11a and the connecting portion 11c of the punch holding section of the frame is of reduced thickness as seen in FIG. 5 so as to facilitate bending of the metal to the configuration shown.

The die section 12 of the frame underlies the lower portion 11b of the die holding section 11 and is in part parallel to the portion 11b. The lower portion 11b of the punch holding section 11 and the die section 12 are joined by a fold line 14 which is of reduced thickness so as to facilitate bending the metal through approximately 180.degree.. The forward portion of the die section 12 is spaced from the lower portion 11b of the die holding section 11 to provide a space S for receiving the paper or other material to be punched. Longitudinally spaced portions 12a of the die section 12 of the frame are partially severed and displaced upwardly into engagement with the lower surface of the lower portion 12b of the die holding section 11. The displaced portions 12a of the die section 12 are spot welded to the lower portion 11 of the punch holding section 11 as indicated at 15 to rigidify and strengthen the frame structure. Forward edges of the offset portions 12a provide abutments which limit the distance of the paper or other material to be punched can be inserted in the space S between the die section 12 and the punch holding section 11. A forward marginal portion 12b of the die section 12 is bent downwardly at an angle to the horizontal as seen in FIG. 5.

The upper and lower portions of the punch holding section 11 are provided with aligned bearing holes 16 to receive the punch assemblies. As seen in FIG. 2 there is a row of holes spaced from one another in a direction longitudinal of the frame. Each of the holes is surrounded by an upstanding collar 16a which provides a longer bearing surface for the punches. The die section 12 is provided with a corresponding number of punching holes 17 which are aligned with the respective bearing holes 16 of the punch holding section. As seen in FIG. 5 the punching holes 17 are flared downwardly so as to provide at the upper surface of the die section 12 shearing edges to facilitate a clean punching operation.

Each of the punch assemblies 2 comprises a punching rod 21 and a conically coiled spring 22. The punching rod 21 has a domed head 21a provided with an annular groove 21b in which seats the upper convolution of the coiled spring 22. This configuration permits assembly of the punching rod 21 and the spring 22 by pressing the spring down over the domed head of the punching rod whereupon the upper convolution of the spring snaps into the groove 21b. The punching rod and spring thereupon remain in assembled relationship. The punching rods 21 are of a diameter to be received with a snug but easily sliding fit in the bearing holes 16 of the frame. The lower convolution of the spring 22 seats on the upper surface of the punch holding section 11 and in relaxed condition as seen in FIG. 5 positions the punching rod with its lower end approximately flush or slightly above the lower surface of the lower portion 11b of the punch holding section 11. The lower end face 21c of the punching rod 21 is preferably shaped as a shallow V as seen in FIG. 5 to provide a better punching operation. The punching device as supplied to a customer includes a suitable number of punch assemblies, for example four or five, which can be placed in selected holes 16 of the frame according to the number and spacing of the holes it is desired to punch.

The operating handle 3 comprises an elongated lever which extends substantially the full length of the punching device and is provided at its forward edge with spaced hook portions 31 which hook into slots provided in upstanding portions 18 of the frame to provide a fulcrum for the lever. The operating handle is formed of sheet metal, plastic or other suitable material. It is shown as being provided with a peripheral rim 32 and with downwardly projecting boss portions 33 which are adapted to engage the domed heads of punching rods 21 assembled in the frame. It will be seen that when downward pressure is exerted on the operating handle 3 so as to pivot it in a counter clockwise direction about its fulcrum, the portions 33 press on the punching rods 21 so as to move them downwardly from the position shown in FIG. 5 and thereby force the lower ends of the punching rods though the material to be punched and into the holes 17 of the die section 12, thereby punching holes in said material. When the operating handle is thereafter released, the springs 22 return the punching rods and the operating handle to the positions shown in FIG. 5.

The base 4 is molded of resilient plastic material, for example polyurethane. It is divided by longitudinally extending hinge lines 41 and 42 of reduced thickness into three sections. An upper rear section 43 slopes upwardly and forwardly from the hinge line 14 and closes the otherwise open rear side of the punch holding section 11 of the frame. A shoulder 43a engages the rear edge of the upper portion 11a of the punch holding section 11. A further portion 43b slopes downwardly and forwardly from the shoulder 43a and is provided at its forward edge with a plurality of slotted fingers 44 which are positioned to engage in annular recessed portions 21d provided in the punching rods 21 between the bearing holes 16 of the upper and lower portions 11a and 11b of the punch holding section 11. When punch assemblies are positioned in the frame as illustrated in FIG. 5, the slotted fingers 44 engage in the recessed portions 21d so as to retain the punch assemblies in the frame and prevent their falling out in the event the punching device is inverted. However, by reason of the resilience of the slotted fingers 44, the punch assemblies can easily be inserted or removed manually from the frame. Moreover, the recessed portions 21d of the punching rods 21 are of sufficient axial length that the slotted fingers 44 do not in any way restrain axial movement of the punching rods during the punching operation and do not act as return springs. Return of the punching rods after a punching operation is effected solely by the conical springs 22.

The upper rear section 43 of the base is also provided with one or more recessed parking holes 43c two such holes being shown in FIG. 3. These parking holes are adapted to receive punch assemblies that are not presently being used for punching. The lower portion 11b and the die section 12 of the frame are provided with aligned holes to permit insertion of the parked punch assemblies as illustrated in FIG. 5.

A lower rear section 45 of the base is of upwardly opening U-shaped cross section comprising a bottom 45a, an upstanding rear portion 45b which joins the upper rear section 43 in the hinge line 41 and an upstanding forward portion 45c which extends up to and assists in supporting the die section 12 of the frame. The upstanding rear portion 45b is provided with two open molded slots 45d to receive lug portions 19 which are dependent from the rear portion of the frame to support the frame and provide attachment between the frame and the base. The lower rear section 45 is further provided with longitudinally spaced transverse wall portions 45e which extend between the rear portion 45b and forward portion 45c and provide further support for the frame.

The third section of the base floor is a front lower section 46 which extends forwardly from the section 45 and underlies the forward portion of the die section 12 of the frame. The section 46 thus underlies the punching holes 17 of the die section and provides a receptacle to receive the punchings. A forward portion 46a of the section 46 underlies the lower edge of the downwardly inclined forward portion 12b of the die section 12 and thereby supports the forward portion of the frame. Moreover the portion 46a of plastic material provides protection for a desk table or other surface on which the punching device is placed to prevent its being scratched or marred by the metal edge of the frame. Just rearwardly of the forward edge portion 46a the section 46 is provided with an upwardly projecting portion 46b of inverted V cross section which engages the inner surface of the downwardly inclined forward portion 12b of the die section 12. Small protuberances 46c on the upwardly projecting portions 46b are received in openings 12c in the downwardly sloping forward portion 12b of the die section 12 to retain the section 46 of the base normally in the closed position shown in FIG. 5. However, the section 46 can be swung downwardly about the flexible hinge 42 in order to open the receptacle formed by the section 46 in order to empty punchings therefrom.

The molded plastic base 4 further has end portions 47 (FIG. 4) which close the otherwise open ends of the frame 1. Moreover, the lower front section 46 of the base has upwardly extending end portions 48 which form ends for the receptacle provided by the section 46.

By reason of the flexible hinge 41 the entire base can be easily molded of plastic material. When molded, the section 43 extends rearwardly from the section 45 and forms in effect a rearward continuation of the sections 45 and 46. After the base has been thus molded, the section 43 is bent upwardly and forwardly about the flexible hinge 41 to the position shown in FIG. 5.

In FIGS. 6 and 7 there is shown a modification in which the forward portion 43b of the upper rear section 43 of the base is provided with a straight edge 44a instead of the fingers 44 shown in FIGs. 3 and 5. The edge 44a engages in the annular recess 21d of the punches 21 to retain the punch assemblies 2 removably in the punch holding section 11 of the frame 1. By reason of the flexibility of the material of the base, the punch assemblies can be readily inserted in and removed from the frame in order to change the number and spacing of holes to be punched. As in the case of the fingers 44 the flexible edge portion 44a of the modification shown in FIGS. 6 and 7 in no way interferes with movement of the punches during a punching operation and does not serve as a return spring, the return of the punches being effected by the conical springs 22.

While the preferred embodiment of the invention has been shown in the drawings and is herein particularly described it will be understood by those skilled in the art that many modifications can be made and that the invention is in no way limited to the illustrated embodiment.