CA2619806A1

CA2619806A1 - Low friction hole punch element

Info

Publication number: CA2619806A1
Application number: CA002619806A
Authority: CA
Inventors: Joel S. Marks
Original assignee: Individual
Current assignee: WorkTools Inc
Priority date: 2005-08-30
Filing date: 2006-08-16
Publication date: 2007-03-08
Also published as: WO2007027444A3; WO2007027444A2; EP1919676A4; EP1919676A2

Abstract

A hole punch device that reduces the force required to create a hole in papers or other sheet media. A punch element of the hole punch device includes a locally sloped or indented floor to create a bend in the sheet media as it is punched to create an enlarged, oval hole. The punch pin may include an expanding sleeve surround the pin that forms a larger diameter during the cutting stroke and springs back to a smaller diameter during a pull out stroke. A coiled torsion return spring is positioned remotely from and non-coaxially with the punch pin. A keyed pin and support frame arrangement ensures a predetermined rotational orientation of the pin for sequential cutting for reduced cutting force. The pin and/or other components optionally include electroless nickel plating to reduce friction and wear at the component or pin sliding and cutting surfaces.

Description

LOW FRICTION HOLE PUNCH ELEMENT
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation-in-part application of co-pending parent application having serial no. 11/215,423, filed August 30, 2005, whose entire contents are hereby incorporated by reference.
FIELD OF THE INVENTION
The present invention relates to hole punching devices used to cut holes in sheet material. More precisely, the present invention relates to a punch pin and support stnicture.
BACKGROUND OF THE INVENTION
A paper punch is a coinmon device found in offices and schools. It is used to cut holes in paper under finger or hand pressure. Typically, a paper punch element includes a pin, and a fraine to support the pin over a paper slot. The pin moves axially, or vertically, into the papers. It is desirable to minimize the force required to cut a hole into a stack of papers since these tools are usually operated ttnder hand or finger pressure.
To be sttre, even a motorized paper punching device benefits from reduced force since a smaller motor may be used.
One method to reduce this force is to cut progressively around the periineter of a hole rather than to cut the entire perimeter of the hole all at once. A well-lcilown method for making a progressive cut is with a "V" cut notch in the end face of the pin. This creates more than one cutting point. The notched end cuts from two opposed sides of the hole toward the center of the hole. The notched end provides two eelual pointed ends of the pin that press the paper stack simultaneously. Other designs use asyinmetrical points or three or more cutting points.
Another concern is jamming of the pin in the paper. Typically, as the pin advances into the hole, the inside diameter edge of the paper is stretched and dragged down into the hole along witll the pin. Then as the pin is withdrawn out of the hole, the edges tend to flip upward and press hard around the pin in a cam action. The hole effectively acts as a one-way cleat, with the hole imler diameter serving as a diaphragm to hold the pin in the hole.
The hole diameter cut in the paper is in fact smaller than the diameter of the pin.
Tlie prior art paper hole puncl7es typically conteinplate a eompression type die spring strong enough to overcome the highest anticipated pull out or retraction force. The pin can typically be retracted only by the spring. Therefore, the spring must provide that - 2 _ PCT/US2006/032151 ftuiction tulder all circtunstances. United States Patent No. 4,757,733 (Barlow) shows a typical arrangement in Fig. 6. Ridge 40 transmits pressure to cap 47 atop each pin (cutting tool 15). Helical spring 45 surrounds the piii. When the pin does not retract in this type of design, the paper becomes jainined in the punching device since there is no fiirther way to force the pin out. This situation is familiar to most users of paper punches.
Also, the force needed to coinpress the die spring directly adds to the hand or operating force required to cut the hole. When a small stack of papers is being cut, the spring force is often greater than the actual cutting force.
There are many hole punch tool and pin designs. For exainple, U.S. Patent No. 5,730,038 (Evans et al.) shows a punch pin cutting end with specified groove depth in relation to a paper stack height, and a force sequence profile. U.S. Patent No. 5,243,887 (Bonge, Jr.) shows a rectangular punch 18 fitted in the rectangular guide hole of a fraine.
The punch is pivotably attached to a lever and secured axially by pin 24. U.S.
Patent No.
4,763,552 (Wagner) discloses a punch pin with a syrmnetric angled cutting end.
U.S.
Patent No. 4,713,995 (Davi) shows a conventional punch element design, including a helical return spring around the pin, and a lever that can only press, not pull, the pin. U.S.
Patent No. 4,449,436 (Semerjian, et al.) shows a cylindrical punch pin that includes a slotted top. A lever rib normally engages the top of the punch pin. An inoperative position for the sheet punch is achieved by rotating the punch pin so that the slot aligns with the lever rib. The rib then moves into the slot rather than pressing the top of the pin.
No apparerit mechanism is disclosed to keep the punch pin in its operative rotational position. The Semerjian '436 patent furthers shows an asyinmetrical pin with one cutting point longer than another.
U.S. Patent No. 4,257,300 (Muzik) discloses a cylindrical punch pin where the pin is secured axially at an aimular groove. A key fitted in a radial slot of the pin positions the pin rotationally. U.S. Patent No. 3,721,144 (Yainainori) shows a tubular punch die element with thin walls and a sharpened lower end. U.S. Patent No. 3,320,843 (Schott, Jr.) shows a tubular punch element that is grotuid shaip at its cutting end.
U.S. Patent No.
4,594,927 (Mori) shows a punch pin held axially in two ways. In one embodiment, a rod 10 passes tluough a drilled hole in the upper body of the punch pin.
Alternatively, an amlular groove fits in a slot of a pressing plate. With the amzular groove, the punch pin is not rotationally fixed in position. The Mori '927 patent shows an inclined base where the pins cut holes in a progressing sequence. The angle is very slight, just adequate to create the sequential cuts while maintaining a reasonable heiglit to the punch device. U.S. Patent No. 4,656,907 (Hymmem) shows a paper punch that may be disassenlbled for, ainong other reasons, to fix jainmed pins. U.S. Patent No. 4,240,572 (Mitsuhashi, et al.) shows a multi-pointed punch pin including a discussion of a punching sequence. U.S.
Patent No.
5,463,922 (Mori) shows a roller system for pressing ptuich pins in a sequence.
Japanese Patent Publication No. 64-087192 (Izumi, et al.) shows a punch pin with elongated cutting points, and a graph showing two force pealcs during the punching operation. Japanese Patent Publication No. 61-172629 (Yulcio) shows different cutting end profiles for a punch pin, including an asymmetrical end. U.S. Patent No.

4,829,867 (Neilsen) shows a fixed diameter sleeve type punch pin with a helical cutting end. U.S.
Patent Nos. 6,688,199 (Godston, et al.) and 4,077,288 (Holland) disclose punches with a vertically oriented or upright paper slot. In the Godson '199 patent, the surrounding stn.icture 532 holds the papers away from the user. As illustrated in Figs. 4 and 9, slot 62 including floor 64 and ceiling 68 are peipendicular to the punch pin axis 50.
Conventional paper punches use hardened, non-coated or non-surface treated steel for the pins. The wear resistance and lubricity of the pin against paper are liinited by inherent sttrface properties of the steel material.
SUMMARY OF THE INVENTION
It is desirable to minimize the pealc forces to ctit a hole or holes in papers or other sheet media in a finger- or hand-pressure operated tool or in a coinpact motorized tool.
The shape at the end of the punch pin is important. One approach is to cut the notch so that the pointed cutting ends are at different levels. Then the lowest pointed end cuts into the paper or sheet first before the higher pointed end, so the force required is less than that with two equal elevation ends cutting into the paper or sheet simultaneously.
One approach to creating different levels for the cutting points is to locate tlie notch in between the cutting points off-center. Another approach is to provide an uneven punch base so that the pointed ends cut into the sloped sheet differently.
To ftu-t11er improve the efficiency of a hole punch, the pull out force of the pin must be reduced. One way to reduce the force is to malce the hole in the paper larger than the pin diameter. A non-circular imler circtunference can make it easier to expand the hole about a circular pin. For example, an oval hole in a sheet with its largest diameter sized greater than the punch pin diameter would allow the punch pin to pull out easily. To create an oval hole with a circular pin, in one embodiment, the base or anvil of the frame should be stibstantially uneven or angled. The paper flexes out of a flat plane at the anvil.
The pin thereby presses the paper at a substantial angle off peipendicular to the punch pin creating a sliglitly ovoid hole. With such an arrangemen.t, the smaller dianleter of the ovoid hole reinains equal or smaller than the pin diaineter, while the larger diaineter of the ovoid hole is larger than the pin diameter. The pin can easily force open the nan-ow direction of the hole when the paper is repositioned peipendicular to the pin since the loose fitting larger diaineter direction can flex toward the pin. The ovoid hole becomes slightly distorted into a round shape that is larger than the simple round hole that is ordinarily made by the pin.
Aiiother approach to ease the pin reinoval is to use an expanding pin. In such an exemplary embodiment, a thin-walled sleeve includes an angled cutting end. The end is ground to a sharp edge and may cut progressively from one side of a hole toward the opposite side. In a preferred einbodiment, the sleeve is formed from a sheet metal blailk into a hollow cylinder, and includes a longitudinal gap between the two opposed edges of the fonned blailk.
The sleeve is expandable whereby it has a larger diameter as it is forced into the paper and a smaller diameter as it is pulled out. The longitudinal gap becomes larger allowing the sleeve to expand. The sleeve at least partially surrounds a punch pin. The punch pin includes a head at the top. Once assembled, the pin is slidable within the sleeve wherein the head is normally spaced above the top of the sleeve. Pressing the pin/sleeve assembly at the pin head into the paper sheet causes the pin to slide down with the head moving toward the sleeve. A groove around the circumference of the pin receives a radially inward facing rib formed in the sleeve, or equivalent structure, so that as the pin slides within the sleeve, the rib slips out of the groove and expands the diaineter of the sleeve. During the downward cutting stroke, the expanded sleeve cuts a hole with a larger diaineter than the sleeve diaineter during the pull out stroke.
Al.i approach to reduce punching effort is to minimize the retuni spring force. A
return spring is coirnnonly used to return the actuation handle back to the start position and to withdraw the punch pin from the pLuiched hole in the sheet material. A
first way to achieve a lighter spring force is to reduce the pull out force described above. A lighter spring provides a particular advantage in liglit duty use, but is also advantageous in any type of punching application. A second way to reduce return spring force is a simplified linlcage that enables a user to directly pull out a pin from a punched hole.
The return spring may then be just strong enough to retract the pin in most circumstances; the retui7l spring need not be so strong that it caiz retract the pin under the worst case. Examples of such worst cases include when ptuzching through a very thick stack of papers when the WO 2007/027444 - $ - PCT/US2006/032151 papers have some glue or other containination, or when the pin has become dull and draws more paper edge into the hole. Iii such worst case instances, the user can augment the return spring power by pulling up upon an operating handle to retract the pin.
Accordingly the spring force may be substantially reduced.
It is desirable to reduce friction and wear in the operation of the pin through a low friction interface. One exainple of such an interface includes a lubricant such as grease.
More pennanent approaches include plating and surface treatments. Ainong surface treatments are polyiner iunpregnated resin coatings, titaniiun nitride, carbon, and metal plating. The treatinents may be applied electrically, chemically, electro-statically, by ion implantation, vapor deposition and other processes. Certain processes such as ion implantation do not change the dimensions of the coinponent being treated.
Other processes add to the thicla-iess of the material to fihe component. Galvanic electroplating, such as nickel or chrome, provides some corrosion protection and limited friction reduction in some cases. However, electroplating does not precisely reproduce the parent surface.
Electroless nickel is a chemically based process that provides low friction, low wear properties on steel and other surfaces. It is especially economical on a small part such as the punch pin of a hole punch for instance, since electroless nickel can be a batch process with ininimal haridling of the small parts. Electroless nickel accurately reproduces the underlying surface too. For exainple, the cutting point may be ground before the plating is added so that the sharp cutting edges are substantially preserved.
In contrast, galvanic electroplated nickel creates an uneven layer; in particular, shaip outside edges such as the cutting points of the pins cause concentration of material wherein an enlarged, rounded bulb or globule of niclcel or other plated metal grows at the edge or corner. Such a roLulded, distorted, blunted corner caiu-iot cut papers well.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a side elevational view of a punch eleznent with a pin shown in hidden view.
Fig. 2 is a partial cross-sectional front view of the punch element taken along line 2-2 of Fig. 1.
Fig. 3 is a side, top perspective view of a pin and retaining clip assenibly.
Fig. 3A is a detail view of an alternative embodiment pin cutting end with a "W"
shaped profile.
Fig. 4 is a side, bottom perspective view of a pin.

Fig. 5 is a side, bottom perspective view of the punch element frame of Fig.
1.
Fig. 6 is a cross-sectional view of the pin within an oval hole formed in a stack of papers.
Fig. 7 is a partial cross-sectional view of the element of Fig. 1 with the pin moved down to an intermediate position.
Fig. 8 is a cross-sectional view of an altenlative embodiment hole punch element assembly.
Fig. 8A is a detail view of Fig. 8, showing the top portion of a ptulch sleeve against a pin head.
Fig. 8B is a detail view of Fig. 8, showing a rib of the sleeve pressing a groove in the pin.
Fig. 9 is a side elevational view of a pin and sleeve assembly.
Fig. 10 is a side, bottom perspective view of the pin and sleeve asseinbly of Fig. 9.
Fig. 11 is a side elevational view of an altenlative embodiment punch element wit11 an actuating bar engaging a pin and a retunz spring in hidden view, with the assembly in an intermediate position.
Fig. 12 is a partial cross-sectional view of the punch element of Fig. 11.
Fig. 13 is a rear, side perspective view of the punch element of Fig. 11.
Fig. 14 is a side elevational view of the punch eleinent of Fig. 11.
Fig. 15 is a rear side view of the punch pin of Figs. 11 to 14.
Fig. 16 is a perspective view of a double torsion return spring.
Fig. 17 is a detail view of a pin wit11 electroless nickel plating.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is directed to a hole punch element. A hole ptnlch element may be defined as the punch pin, or as the stntcture within the inunediate region of the hole punch device near the pin including the structures that guide the pin and the sheet media or substrate to be punched, sttch as a stack of papers. For exainple, a die cast punch suppoi.-t stntcture may guide pins as well as support an operating handle.
Figures 1 to 7 show one exeinplary embodiment of an improved punch element.
Pin 20 is vertically slidable and guided in fraine 10 along a longitudinal pin axis, depicted as a vertical, dashed line. In Fig. 1, pin 20 is shown in an intennediate position between an uppennost position and a lowennost position. Lower cutting point 21a of pin 20 is just protruding into anvil cavity 13. Upper cutting point 21b of pin 20 has not entered cavity 13 in Fig, 1.

Tie bar 100 is linked to pin 20. Tie bar 100 is preferably a side facing "U"
chamlel in the illustrated embodiment. Linlcages acting as the tie bar of other shapes aside from a "U" chamlel are coritemplated. 1ii a inultiple hole punch, such as a three hole punch, tie bar 100 actuates tllree punch elements spaced along a lengtll of tie bar 100.
Tie bar 100 links the pins to a ftu-ther actuating mechanism shown schematically as handle 107.
Handle 107 is pivotably attached to frame 10, either directly as shown at pivot 104 or to a housing body (not shown) that supports one or more fraines or punch element portions and an actuating lever system. Handle 107 is also pivotably attached to tie bar 100. Some optional sliding motion is allowed at pivot 103 in the instance that handle 107 moves by rotation as shown. lii the preferred embodiment, handle 107 can press downward upon tie bar 100 and optionally pull up on tie bar 100 via pivot 103.
Pin 20, tie bar 100, handle 107 or any combination of these components or equivalent stilictures may be driven not only by direct manual force of a user's hand but also by a motor or by hydraulics. For example, a motor (not shown) may rotate an eccentric cam and the cam selectively engages tie bar 100 from above to force tie bar 100 downward as in Fig. 1.

When a user depresses handle 107 which rotates about pivot 104, pivot 103 translates the rotational handle motion into a vertical translation of tie bar 100. Upper wall 102 of tie bar 100 presses atop pin 20 to urge pin 20 into papers 51 or otller sheet material, as seen Fig. 2. Still in Fig. 2, lower wall 104 includes recess 105 formed into the lower edge of tie bar 100 to at least partially sLu-round lower body portion 24 of pin 20. Spring clip 70 fits into circmnferential groove 25 of pin 20. Lower wall 104 of tie bar 100 fits under spring clip 70 at recess 105. Wit11 the contacts at pivot 103 and/or spring clip 70, tie bar 100 can press pin 20 in a downward stroke in response to a user's pressing action upon haiidle 107. Moreover, as tie bar 100 is raised by handle 107 via pivot 103, tie bar 100 also lifts pin 20 in an upward stroke through the spring clip 70 liiikage at recess 105.
Therefore, a user may easily lift pin 20 directly if the pin becomes stuck in a hole that the pin cut into the stack of papers 51. This capability contrasts with the conventional light duty hole punch where an operating handle can only press punch pins, but camlot lift the pins since there is no tensile liiAc to the pin to enable a retracting stroke.
The present invention exeinplary embodiment provides a much simpler lifting mechanism than, for example, a pin that has a cross drilled hole holding a dowel used to attach the pin to a lifting arm to enable the lifting stroke. Cross drilling a cylindrical pin through its centerline is costly and difficult to manufacture.

WO 2007/027444 - 8 _ PCT/US2006/032151 hi Figs. 2 and 5, shelf 17 provides an optional upper stop for spring clip 70.
Ii-i Fig.
2 it is seen that shelf 17 is similar in thiclaiess to lower wall 104 of tie bar 100. As pin 20 inoves up to its upper niost position, spring clip 70 contacts shelf 17. A gap remains to allow lower wall 104 of tie bar 100 to fit in between ceiling 11 of frame 10 and spring clip 70. Therefore, if the punch element is removed, for exainple to change its position from two hole punching to tluee hole punching, the gap between ceiling 11 and spring clip 70 remains so that the punch element can be reinstalled into recess 105 and liiilced to tie bar 100. The present einbodiment thus benefits from quick and easy interchangeability of the punch elements. The gap also helps in initial manufacturing assembly of tie bar 100 about pin 20.
Frame 10 includes side walls and an opening facing rearward, in the leftward direction in Fig. 5, to create an optional, partially enclosed space. Pin 20 is therefore exposed rearward in frame 10. As best seen in Fig. 5, rearward is defined as the direction in which slot 19 tei7ninates, which is opposite to the direction toward which slot 19 opens.
This arrangement allows lower wall 104 of tie bar 100 to engage pin 20 using a simple recess 105 foi7ned in an edge of tie bar 100. Accordingly, the aforementioned einbodiment provides a punch pin that can be botli pressed into and pulled out of sheet media via a siinple lii-Acage systeiu.
Aiother feature of the prefeiTed embodiment is a reduction in force needed to pull out a pin from a hole the pin has made in a stack of papers 51. In the embodiinent shown in Fig. 2, slot 19 has upper floor 18a and lower floor 1 Sa'. Slot 19 includes anvil cavity 13 fonned in angled section floor 18c. Angled section floor 18c stu-rounds or nearly surrounds anvil cavity 13. Collectively, the floor sections 18a, 18a' and 18c forin ai1 uneven or stepped punch element floor. Preferably, angled section floor 1 8c is at a slope angle of about 5 to 25 inclusive across a diameter of pin 20, including all angles therebetween, relative to generally level floor 18a or l8a'. According to basic trigonometry, an angle of 25 across the pin diameter corresponds to an elevation change of about 50 % of the pin diameter. An angle of 5 corresponds to an elevation change of about 8 % of the pin diameter. A1tenlatively, the uneven or stepped floor may be locally steeper than the given range of 5 to 25 . In such an embodiment, a nearly vertical or entirely vertical region of anvil cavity 13 can be formed in an area sinaller than the diameter of pin 20 in combination with or in place of the larger-area, 5 -to-25 sloped section floor 18c. According to the trigonometric relationship described above, in this smaller area, the elevation change across the pin diaineter preferably ranges inclusively fioin about 8 % to 50 % of the pin diaineter. In still other alten7ative embodiments, sloped section floor 18c may be angled anywhere from about 2 to 90 inclusive.
The distance between upper floor 18a and ceiling 18b may be a paper thicl(lzess limit. More generally, the smallest height of slot 19 can serve as the paper thiclcness limiter, and in Fig. 2, this is the height at the left side of slot 19 or the distance between 18a and 18b. The paper thiclcless limit defines the capacity of the punch element or hole punch device and restricts the punch element or hole punch device to use with a pre-detennined nunlber of sheets of a given thiclaless paper. The capacity may be selected to match available leverage or pressing force, or for marlceting reasons.
Aiiother way to describe the locally angled or stepped section floor is in relation to a paper guide slot in a multi-element hole punch. In such an asseinbly of a hole punch structure (not shown), two or more punch elements are spaced side-by-side.
Each punch element appears as in Fig. 2 to provide for separate holes in a stack of papers. Slots 19 of the two punch elements define the paper guide slot, with co-planar floors 18a or 18a' being the bottom of the slot. The paper normally lies in the plane defined by floors 18a or 18a'.
This plane may be called the "slot plane." This plane may be visualized in its relevant direction by extending the opposed edges of papers 51 of Fig. 2. It may be described by a general level for floors of adjacently spaced punch elements that liold the position of papers 51 as defined by the same position on each punch element, for example, floor 18a' of each punch element. Angled section 18c is therefore described as a bent area local to pin 20 that is sloped at about 5 to 25 out of plane, or comparably, an elevation change of about 8 % to 50 % of the pin diameter across pin 20. This local bent area in floor 18c guides and offsets the paper stack out of the slot plane near pin 20 when the paper stack is compressed by pin 20. In an alternative einbodiment, the slot floor may include local arcuate portions to create such an offset.
Notably, the term "plane" is intended to include a non-linear, sloped, and/or arcuate floor for the in and out direction, or left to right in Fig. 1. The "paper path" defined by floor 18a, 18a' and angled section floor 18c may alternatively be described as a bent line bisecting the respective pin axes of the multiple elements rather than a bent plane comlecting the nlultiple elements. The paper is bent to follow the uneven or kinked paper path as pins 80 of multiple punch elements press the paper against respective bases of the elements.
In a conventional, multiple punch element design, the floors define a straight, smooth, and slightly inclined path. hi contrast, angled or stepped section floor 18c or equivalent structtue in the preferred embodiment of the present invention defines an offset, out-of-plane or out-of-line section from the generally straight inclined path to create a local bend in papers proximate to each pin. fi1 the instance of a smootll inclined path, if ceilings 18b of the respective elements are at the saine level, then the slot heigllt is different for each element. Typically, the smallest height portion of the smallest slot 19 defines the maximum paper thickness in the multiple-element hole punch device.
As seen in Fig. 2, when pin 20 presses on papers 51 held in slot 19, the papers are forced to bend to follow the surface contour of angled section 18c. As a result, the angled entry of pin 20 into the papers causes the apparent shape of pin 20 at the papers to be an oval. The resulting hole created by pin 20 in papers 51 is also an oval with its long axis or diaineter slightly larger than the actual diameter of pin 20.
Optionally, the entire surface of the floor may be angled as with angled section floor 18c to foim the out of path section. In this einbodiment, the fonnerly level surfaces of floors 18 and 18a' would now be sloped. This worlcs best if the floor stuface generally underlying the punch element is narrow from side to side to avoid a large elevation change from one side of the pin to the other. That local area generally underlying the pin may span a width of just smaller than the pin diameter to a width of up to about 5 pin diameters.
By fiirther extending the size of the angled section of floor 18a and 18c --higher on the left in Fig. 2 and lower on the rigllt -- papers 51 will be offset more than necessary. The extreme offset may be apparent to a user who might find the appearance peculiar, and may hinder the ease with which papers can be fed into slot 19. Consequently, the extreme offset requires an excessively tall slot 19 for clearance, which carries over into undesired increased bulk of the hole punch device.
Similarly, a highly inclined path coiulecting together multiple punch elements can provide oval holes. However, the resulting slot height at the lowest area of the floor would be unsatisfactory for typical spacing between multiple punch elements. It is thus desirable to have a substantially inclined floor or path, but with a size limited to the immediate vicinity of the pin. With this aiTangement can the hole be usefiilly oval while maintaining a reasonable slot height for all punch elements and suiTounding support stnictures.
The force of adhesion of pin 20 wit11 the inside wall of the punched hole is reduced when the hole is oval shaped and the pin cross-section is a circle. The benefit is greatest if papers 51 are tilted from the angled position to a peipendicular position about pin 20 before the pin is withdrawn. In the angled position, the oval hole remains tightly fit around the pin since the hole was created in this condition. But if the paper is tilted to be substantially perpendicular to pin 20, the hole effectively expands to be larger than the pin diameter along the long axis of the oval hole. The short axis remains the salne size relative to the pin. As mentioned above, the slope of angle section 18c relative to tlie liorizontal floor 18a should preferably be greater than about 5 or the oval shape will be too subtle to be very effective. If the angle is greater than about 25 across the pin diameter, pin 20 might slide along papers 51 more than actLially cutting through the papers.
Also, the pin will be too strongly biased off the pin axis by the angled entry into the papers and might not properly enter anvil cavity 13. Through empirical observations, the slope angle is more preferably about 10 to 15 111cILlslve lllcludlllg all values between the limits and most preferably about 11 to optimize the above-mentioned benefits.
In Fig. 2, floor section 18c is angled off the perpendicular with respect to the pin axis, while ceiling 18b is horizontal. As pin 20 is withdrawn in an upward stroke, papers 51 tend to adliere to the pin. The papers are pulled up against ceiling 18b.
At this moment, papers 51 are tilted and re-oriented toward the perpendicular since ceiling 18b is perpendicular to the axis of pin 20. As a result and as shown in Fig. 6, oval hole 50 then has a loose fit about the circular cross-section of pin 20. In its more flat orientation, oval hole 50 is generally larger in area than pin 20 and contacts the pin only at the two tangential areas shown in Fig. 6. The hole is thus easily distorted toward a round shape to fit loosely about pin 20, enabling a low force withdrawal of pin 20 out of the punched hole.
A conventional round hole or near-round hole that fits tightly around the entire circtmzference of the pin has no ability to be distol-ted for a loose fitment around the pin, other than by stretching or tearing the paper material. Hence, the force needed to witlldraw the present invention pin from the punched hole is thus reduced significantly.
An oval shaped pin with an oval anvil cavity 13 creates an oval hole in a conventional punch device, but unless the hole is actually larger than the pin as disclosed here, there is minimal advantage in reducing pull out force. Thus, in one alternative embodiment, an oval pin (not shown) installed in the asselnbly of Figs. 1 and 2, with anvil cavity 13 being similarly oval shaped would provide reduced pull out force.
Ili general, it is not required that the pin be precisely round according to the present invention.
The present invention fiu-ther colitelnplates an efficient hole pullcll design that enjoys reduced cutting forces. In particular, it is preferred that the pealc forces are reduced.
In a preferred embodiment, an asynunetrical cutting end of the pin enables such reduced peak forces. In Figs. 2 and 4, it is seen that in the asyinlnetrical cutting end, lower cutting point 21a cuts papers 51 before upper point 21b by virtue of the cutting poilits being at different heights or levels. Therefore, the two cutting points 21a, 21b cut into papers 51 via different approaches and at different moments in time at any position of pin 20. The different engaging cuts of ctitting points 21a, 21b reduces the overall pealc forces since the pealc force is the sum of the forces acting on cutting points 21a, 21b and upper vertex 21c, and at a given position of lower point 21 a, its cutting action occurs vvllen upper point 21b is not perfoi7ning a difficult cutting action. In Fig. 2, lower poin.t 21 a has broken through the last page of papers 51 and entered anvil cavity 13. The force from lower point 21 a is past the break-through peak. At this moment, upper cutting point 21b is perfonning the pealc force entry cut. So the required force on pin 20 is primarily from only one of the two points, namely, upper point 21b in the position shown in Fig. 2.
Sequentially, the cutting force peaks when the point 21a first enters papers 51, then second point 21b engages the papers, and finally when upper vertex 21c first enters the papers. In the interim, as the inteimediate pages are being cut, the force encotultered by pin 20 is lower. As lower point 21a cuts througli the intei7nediate pages, upper point 21b enters the first page. The two cutting points meet at upper vertex 21c. Upper vertex 21c may be off center as shown in Fig. 4 so that the two cutting points are at the respective high and low positions while the angle of the cut notch to make the points is the saine to each side of upper vertex 21c. Cutting points 21a and 21b are a specified axial distance from vertex 21c to define a groove height. Cutting forces may be minimized if the groove heigllt is preferably at least twice the miniinum slot height between floor 18a and ceiling 18b.
Figure 3a shows an alternative embodiment pin cutting end. Center point 21d provides an additional cutting point and additional vertices to create an approximate inverted "W" profile as depicted in the drawing. The "W" profile provides a smooth cutting action near the end of a stroke of pin 20 since the additional vertices are available to shear papers. Also, the center vertex of the "W" profile is preferably slightly off the center axis of pin 20. hi various altenzative embodiments, the "W" profile may be modified with fewer or additional vertices with peaks of tulifonn or varying amplitudes, creating a serrated surface. The "W" profile of Fig. 3a optionally includes asyinmetrical outer cutting points 21a and 21b similar to the asyinmetrical ctitting points 21a, 21b of pin 20 shown in Fig. 4. , In Fig. 2, angled floor 18c may serve an additional fi.ulction to the redtlced pin pull out force discussed above. If a syinmetrical cutting end is used for pin 20 where cutting points 21a and 21b are at the saine axial position or height on pin 20, the syirunetrical cutting points can still cut sequentially, i.e., at different moments in time since the point adjacent to the higher level of floor 18a -- the left side in Fig. 2 -- cuts first before the other point. Therefore, the use of angled floor section 18c provides reduced cutting force even with syinmetrical cutting points. A syminetrical pin may then be used in combination with angled floor 18c to provide sequential cutting end action. Or a slightly asynuiietrical pin may be used and the angled floor eiillances the sequential cutting action.
It is desirable that pin 20 maintain a fixed rotational position in fraine 10, especially when the floor of slot 19 is not peipendicular to the pin axis.
With a fixed rotational pin position, a particular cutting point, 21a in this example, always faces left in Fig. 2 and into the page in Fig. 1 where the point is adjacent to the highest part of anvil cavity 13. One advantage of a fixed rotational position is to ensure the sequential cutting action described above. In Fig. 2, cutting points 21a and 21b are held to each side of the step in the floor of slot 19. So even if the cutting ends are at the same level, the points still cut in sequence: point 21a first and point 21b next.
In the Figs. 3 and 4 einbodiments, pin 20 has an optional flat outer surface 22.
Thus, pin 20 includes a wide, D-shaped transverse cross-sectional area in the portion with flat side surface 22 where flat surface 22 transitions to a curved outer surface of pin 20.
Top hole 15 of frame 10 includes substantially flat interior surface 16 acting as a keyway, as best seen in Fig. 5. Surface 16 may be slightly arcuate. The respective flats 16, 22 are thus keyed to each other. When assembled together, pin 20 slides axially in frame 10 while supported by top hole 15 and guide hole 14. Pin 20, however, caiulot rotate because the keyed flat side 22 engages corresponding flat surface 16.
In an alternative einbodiment, pin 20 may be keyed to frame 10 by means of a protrusion fitted to a longitudinal groove of the pin (not shown). For exainple, top hole 15 may have an inward extending tab and pin 20 may have a coiTesponding longitudinal groove to receive the tab. The keyed flats 16, 22 of the illustrated einbodiment are easier to manufacture than a groove machined into a pin since flat 22 is a single surface extended to connect two edges of the cylindrical outer surface of pin 20. Flat surface 22 can be cut in a direction peipendicular to the pin axis. In contrast, a longitudinal groove or keyway must be milled along the direction of the pin axis increasing manufacturing cost and complexity.
When papers 51 are inconipletely punched, a paper chip can remain attached or dan.gling from the stack of papers. In the prior art hole punches, this condition often causes a ja1n; the chip becomes wedged in slot 19 and the papers caiuiot be removed from WO 2007/027444 _ 14 _ PCT/US2006/032151 the hole punch device. The present invention, on the other hand, contemplates that if the circular chip is cut in a predetermined direction, this ensures that the cllip caiu-iot become wedged.
To illustrate, in Fig. 7, a partially punched stack of papers is shown. Chip represents the small, stacked, circle of paper that is to be cut out. The individual chips are incompletely severed from the stack of papers and are attached by tabs 52 dangling the chips. In the exemplary embodiinent of the present invention, upper vertex 21c is rotationally oriented as shown witli the lowest part of vei-tex 21c preferably positioned away from the open end of slot 19, i.e., to the left in Fig. 7. The highest end of vertex 21c is thus rotationally oriented nearest tab 52. If there is incoinplete cutting, tab 52 is most likely located near the open end of slot 19. With this pin 20 and vertex 21c orientation, if chip 53 remains attached to the stack of papers at tab 52, papers 51 can still be forcibly removed from slot 19 after pin 20 is raised since tab 52 caiulot catch on any part of pin 20 or the surrounding hole punch stitiicture. Further, cliip 53 flexes about tab 52 and swings back in plane with the surrounding paper material as the papers are pulled from slot 19, i.e., toward the right in Fig. 7.
On the other hand, if vertex 21c were angled oppositely to that shown in Fig.
7, with the lower part of vertex 21c located nearest to the open end of slot 19, then chip 53 can becoine jainmed after a partial cut. Specifically, the chip edge presses inside anvil cavity 13 and the ch.ip may bend over into the 11ole. This can be visualized by assunling papers 51 are forced to move to the left in Fig. 7 (disregarding the tenninating left side wall of slot 19). Chip 53 would fold downward into cavity 13 and backward to effectively double the thiclu-less of the papers. The papers will no longer fit in slot 19 and will become jammed. Empirical testing has confinned this jamming behavior.
The cutting end of pin 20 may coinprise different configurations beyond that shown. For exainple, syinmetrical cutting ends may be used. If tlle floor of slot 19 were angled as discussed below for Fig. 14, then a symmetrical pin has the same benefit as that discussed for Fig. 7. To provide the anti jamming benefit, the last area to be cut, and therefore the highest cutting edge of pin 20 or lowest area of the floor, should be facing at least generally toward the open end of slot 19. To maintain this orientation of the cutting edge, a rotational positioning feature such as flats 22, 16 described above may be used.
In summary, there are various possible cutting end designs for pin 20 including syinmetrical and asyminetrical cutting points. These cutting ends may be used with various designs for the angled seginents in the floor of slot 19 such as different angles or shapes as discussed above. For each coinbination of these variables, an optinlum rotational position for pin 20 may be empirically detennined where januning as described in the preceding paragraph is minimized. Figure 7 shows one such combination and rotational orientation for pin 20. hi any combination, the stiLicture described at the upper portion of the pin can hold the pin cutting end in a selected orientation as required.
In an alteniative embodiment, an expanding sleeve is used to redtice the pull out force of the pin. Figure 8 shows coinponents of a paper punch element according to this alternative einbodiment. Housing 160 includes slot 165 to fit an edge of a stack of papers.
A pin assembly is slidably fitted in chainber 164. According to this embodiment, the pin assembly includes two components, central pin 120 fitted within sleeve 110.
Pin 120 at the top end has pin head 124 with a slightly enlarged diameter and near the bottom groove 122 forined around the circumference of the pin. Sleeve 110 has a loiigitudinal gap 115 sparuiing end-to-end and an inward extending rib 113 fonned in the circumference near the bottom thereof.

Norinally, pin 120 is in a rest position witll a sliglltly raised position relative to sleeve 110 as seen by the space between sleeve top edge 114 and head lower face 124a in Fig. 8A. Also while in the rest position, rib 113 fits into groove 122, and gap 115 is closed or nearly closed. Pressing down upon pin head 124 forces sleeve cutting end 112 into the papers (not shown). The resulting upward axial force on sleeve 110 and downward force on pin 120 cause pin 120 to slide farther down into sleeve 110, and the space at edge 114 is reduced or eliminated. When the space at edge 114 is reduced or eliininated, continuing to drive down on head 124 concurrently displaces sleeve 110 downward.
Groove 122 of pin 120 includes top wall 123 and lower wall 126. As pin 120 slides down within sleeve 110, top wall 123 presses circuinferential rib 113.
The resulting wedge action, as best seen in Fig. 8B expands sleeve 110 into a slightly enlarged diameter.
Gap 115 splits farther open enabling the diametrical increase, as seen in Figs. 9 and 10.
This diametrical expansion via increased gap 115 ranges between about 1% to 3 %
inclusive of the sleeve diameter. During the upward, pull out stroke, sleeve 110 is retained on pin 120 by rib 113 engaging groove lower wall 126.
Sleeve cutting end 112 may be continuously cuigled so that the hole is cLlt progressively from one side of the hole diameter to the opposite side. Or cutting end 112 may include two or more cutting points. Sleeve 110 may be formed from sheet steel, where the sharp cutting edge shown is ground before the sleeve is rolled into the tubular shape shown. The sheet steel preferably has some elasticity or resilience.
Tllus, as the pin assembly of pin 120 and sleeve 110 is pressed tlirough the papers, sleeve 110 easily expands. When the downward pressure is relieved, sleeve 110 contracts to its rest position due to springback, forcing pin 120 upward, restoring space at top edge 114, and closing gap 115. Sleeve 110 is then smaller in diaineter than the hole it just created in the paper enabling a low fiiction pull out of the pin assembly from the hole in the paper. By maintaining preferably about a 1 % to 3 % dialnetrical enlargeinent, gap 115 will not become so large to inhibit cutting action of the lower edge of sleeve I10.
Lastly, it is contemplated that the locations of the rib and the groove can be reversed so that the groove is fonned in the sleeve and the rib is fonned in the pin.
Figures 11 to 16 show an altenlative einbodiment of the solid-pin based punch element of Figs. 1 to 7. In this einbodiinent as seen in Fig. 15, pin 80 includes transverse slot 84 with step 83. Fraine 60 includes 'a hollow interior to fit retunz spring 90. Retunl spring 90 is preferably a torsion spring. The spring has upper end 91 and lower end 93 and preferably dual coils 92. Coils 92 are positioned remotely from pin 80 rather than coaxial with or adjacent to the pin as with prior art helical return springs. As illustrated, coils 92 are housed within an enclosed space of frame 60 for improved appearance and protection of the spring. Of course, frame 60 may optionally include openings in front wall 65 and/or in one or more of the side walls. Face 85 of pin 80 contacts edge 61 of frame 60 in an uppennost position of pin 80 (not shown) according to one einbodiznent of a stop structure.
Upper spring end 91 engages slot 84 against step 83. As seen in Fig. 12, lower end 93 fits into recess 62 of fiame 60. Lower end 93 preferably includes an optional bent segment as shown to extend into recess 62. Upper end 91 presses ceiling 84c of slot 84 in pin 80. Ceiling 84c is optionally angled as shown in Fig. 14 so that return spring 90 is biased to press against vertical shelf 83, to the left in Fig. 14. Retlinl spring 90 therefore provides a lifting bias to pin 80, which must be countered by the user during a downward punching stroke of the pin.
In a preferred enibodiment, return sprin.g 90 is a double torsion spring including two substantially concentric coils 92, but other spring configurations such as a leaf spring or cantilevered spring can be used. The fiuzction of coils 92 is provided by the helical coiled portion of the spring, wliere the helical coil for this puipose is the coil of a torsion spring. In the return spring 90 of Fig. 16, two arms 95 are joined by a com.-iecting segment at upper end 91. Anns 95 angle toward each other moving from upper end 91 toward coils 92. Anns 95 may then wrap circuinferentially around a portion of the body of pin 80 to retain the spring against the pin. This wrapping retention may act in addition to or instead WO 2007/027444 _ 17- PCT/US2006/032151 of the angle bias discussed for ceiling 84c. Anns 95 inay include fiu-ther distinct bends (not shown) to more completely suiTound or wrap pin 80 from behind the pin.
Using the upper and lower fi'tment of return spring 90 to frame 80 as described, the spring is securely held in the assembly.
Torsion spring coils 92 can store substantial energy in a coinpact space in contrast to conventional return springs. Such conventional springs have typically been simple colnpression springs sun'ounding the pin and pressing a spring clip that is fitted around tlie pin. With a lower energy helical compression spring as in the prior art, the bias force increases greatly as the pin is pressed downward. But the conventional compression spring camiot fit a large nuna.ber of coils in the limited space surrounding the pin, and fewer coils mean a higher spring constant k and a stiffer action. An inescapable result of a stiff action is that the force to operate the conventional hole punch is needlessly high as an operating handle is pressed downward toward its limit. This effect is particularly evident when fewer stacked paper sheets are being punched. With conventional hole punches then, most of the effort is used merely to overcome the force of the return spring in many applications. This is best obseived by pressing a conventional punch with no papers inserted yet the downward force on the handle is uiuiecessarily high.
In contrast, torsion spring coils 92 are positioned remotely from and are not placed coaxially with pin 80, as seen in Fig. 14. Aims 95 of spring 90 may be relatively long.
Then a given pin displacement causes a relatively small angular deflection of coil 92 resulting in a small increase in spring bias. This is a specific advantage of a torsion spring functioning as a return spring over a helical conlpression spring fitted coaxially or in parallel to the ptuich pin.
Optionally, a long, flat bar or other elongated, axially bendable spring may be attached to the punch device at a location remote from pin 80 and extended to pin 80 to bias the pin upward out of the punched hole. In still another alternative embodiment, a helical compression type spring may be remotely mounted from pin 80 with extended upper and lower arms stretching radially from the spring (not shown). More precisely, a helical spring coil may be situated axially parallel along side pin 80 but not be mounted coaxially to pin 80, while the coil tenninates in stranded wire arins at respective upper and low ends with the ternninal wires extending radially outward toward pin 80.
Here, the helical spring is not placed primarily Lulder coinpression but rather bends along its axis during deflection as the extended anns move toward each other with pin 80. The bending WO 2007/027444 - 1 g_ PCT/US2006/032151 and biasing action of the helical spring as applied to this embodiment is tllus similar to coiled torsion spring 90.

As similarly discussed above for Figs. 1 to 7, pin 80 is axially movable or slidable in frame 60 within lower guide opening 68 and tipper gitide opening 64. The pin is rotatably fixed by flat 82 of pin 80 abutting flat 66 of opening 64, as best seen in Fig. 13.
For manufacturing efficiency, slot 84 and flat surface 82 may extend transversely in a parallel direction as shown.
Pin 80 is further rotatably positioned by engagement with spring 90 as described above. The coiulecting seginent at upper end 91 optionally includes two corners as shown.
As spring 90 wraps around pin 80, these two spring conzers of upper end 91 engage step 83 to hold pin 80 rotationally. In an alternative embodiment, pin 80 may be positioned primarily or entirely by engagement with spring 90. Other geometries may be used to rotatably lii-ik pin 80 to spring 90 or other type of rettun spring. For example, a helical spring may include one or more wires extending radially to engage recesses or slots in a pin and in frame 60. Alternatively, a flat leaf spring may contact pin 80 at an edge of the flat spring.
There are various constructions for lii-ilcing a punch pin to an actuating mechanism such as a lever or handle. For example, an aiulular groove on the pin may fit into a slot of an actuating meinber. However, the groove caiulot rotationally secure or immobilize the pin. To address this rotation, the pin may be notched as a keyway to accept an extension or key from the supporting fraine. This then rotationally fixes the pin. But such a notch is difficult to cut into the cylindrical surface of a typical pin. A dowel may bisect the pin through a drilled hole in the pin. This can rotationally secure the pin, but again it is difficult to manufacture. In particular, it is a complicated process to drill through a cylindrical part, and tedious to assemble a dowel into such an assembly.
In Figs. 12 and 14, tie bar 200 is shown with optional leg 201 extending into slot 84. See also Fig. 15. Tie bar 200 is part of a hole punch device that includes an actuating handle (not shown) similar to handle 107 of Fig. 1. The handle is linlced to tie bar 200 to press downward upon the tie bar. The handle is also preferably linlced to tie bar 200 so that the tie bar may be pulled upward through, for example, a linkage shown as lever 107 in Fig. 1. Other actuating devices may be used to move tie bar 200 such as a cam, l~lob, motor, or other user interfaces lczown in the art. Other configurations for tie bar 200 may be used as well, such as a "U" chaiuzel, "Z" fonn, a bent rod, or flat fonn.

WO 2007/027444 _ 19_ PCT/US2006/032151 As tie bar 200 presses pin 80 downward, leg 201 presses lower horizontal wall 84a of slot 84. When pulling upward upon pin 80, leg 201 presses upper horizontal wall 84b of slot 84. As discussed above, return spring 90 presses ceiling 84c immediately above upper wall 84b. The tenn "slot" is intended to encolnpass the various structures just described that provide the ftulctions of walls 84a and 84b and ceiling 84c. b1 alteniative embodiments, the slot may be in the form of steps, ridges, teeth, serrations, indentations, grooves, or the like. Optionally, ceiling 84c and upper wall 84b may be a coinlnon surface. Then leg 201 reinains under retunl spring 90, but presses upward on upper end 91 of spring 90 directly. Or alternatively, return spring 90 could be located tuldenleath leg 201, and leg 201 presses lower wall 84a via a thickness or diameter of return spring 90.
Spring 90 then biases pin 80 upward through a thiclc-iess of leg 201.
Slot 84 and flat 82 are preferably cut to a depth of about halfway througli the diameter of pin 80. This provides a substantial surface for the respective actions of flat 66 and leg 201, as seen in Fig. 13. Flat 82 and slot 84 may be cut from the same direction as shown so that the tenninating wall of slot 84 and flat 82 face the same radial direction.
Such a structure may be optimal for production since a single machining operation can cut all such features. Alteniatively, flat 82 and slot 84 may face opposite or different radial directions. Flat 82 may be modified to include an arcuate portion, curved either along the axial direction (side view) or along the radial direction (end view).
In another embodiment, spring 90 does not engage an individual pin 80. Rather, a return spring acts to bias tie bar 200 upward. The tie bar in tuni biases pin 80 upward by pressing upper wall 84b. The retunl spring may be a torsion, helical, flat or bar spring.
Tie bar 200 preferably links to and actuates more than one punch element. Of course, the tie bar may optionally be linked to and operate a single punch element. Lever 107 of Fig. 1 or like actuating devices operate tie bar 200 and tie bar 200 in tuni actuates either a single or nzultiple punch elements. The pullch elements are supported by stu-rounding hole punch structtues (not shown). Such stn.tctures normally include, for instance, an attaclunent member to hold the punch elenient or elements to the device, a lil-Jcage to an actuating handle or lever, a ruler with detents for precisely spacing the punch elements a specific distance apart, and a receptacle to receive cut out paper chips.
In Figs. 11 to 13, frame 60 includes feed slot 69 with floor 69a and ceiling 69b.
Floor 69a may have a locally angled portion as described in colnlection with Figs. 1 to 7.
Ti7 the embodiment shown in Fig. 12, however, the locally angled portion includes a"V"
shaped indentation in floor 69a having sides 67 angled off the perpendicular to the pin axis and meeting at vertex 67a. The "V" shaped indentation is foi7ned with opposed sides 67 bending downward froin the generally flat surface of floor 69a; the legs of the "V" span the area of floor 69a local or proximate to each pin 80. In various preferred embodiments, the span of the legs of the "V" shaped indention falls within a range of about just under 10 % of the pin diaineter up to 5 pin diameters. The indented sides 67 are partly visible in Fig. 13. In Fig. 12, papers 51 are deflected out of plane to approximately follow the "V"
profile. As pin 80 is retracted after cutting a hole in papers 51, the papers are slightly lifted and flattened against ceiling 69b; this lifting and flattening re-orients the angle of the papers in the area of the pin to be approximately perpendicular to the pin's elongate axis.
The punched hole is elongated on each side of the basic circular opening to forin an oval shaped hole similar to that shown in Fig. 6. The retraction or pull out force is thus reduced as discussed earlier. A1tenlatively, the indentation in floor 69a may be a "U"
shape, a groove, a dip, a channel, a step down or other profile including simply a lowered central,area. For best performance, it has been enipirically detennined that the angle of sides 67 should be preferably between about 5 to 25 inclusive, includiiig all angles therebetween, relative to the surrounding floor 69a or relative to a perpendicular off the pin's elongate axis. hi still other altei77ative embodiments, the angle of sides 67 may fall within a range of about 2 to 90 inclusive. As discussed for Fig. 2, the preferred angle corresponds to a change in elevation. Across the pin diaineter the indented design of Fig.
12 includes half the elevation change coinpared to a single angled seginent for an eclual angle of the segments. This is because the angle extends for half the distance, one half the pin diameter according to the current trigonometric relationships. Therefore, to use the figures from the discussion of Fig. 1 to 7, the angular range of 5 to 25 coiTesponds to a vertex 67a that is lower than floor 69a by a depth ranging fiom about 4 % to 25 % of the pin diameter.
Another way to describe the angled floor section is in relation to a paper guide slot in a multi-element hole ptulch. In an assembly of a hole punch structure (not shown), two or more punch eleinents like that shown in Fig. 12 are spaced side-by-side to provide for separate holes in a stack of papers. liidividual feed slots 69 of the two punch elements collectively define the paper guide slot, with at least one portion of floor 69a being the bottom of the slot. The paper nonnally lies in the plane defined by a sanie portion of the floor 69a on each spaced punch element. This plane may be called the "slot plane." The slot plane may be visualized in its relevant direction by the extended direction of papers 51 in Fig. 12. It is described by a general level for floors of adjacent spaced elements to define the position of papers 51. Indented and sloped sides 67 have a local, approximately to 25 out of plane area or bend near to each pin 80. This local slope or bend guides the paper out of plane, or offset, near pin 80 when the paper is pressed by pin 80. The tenn "plane" is intended to include a non-linear floor for the in and out direction, i.e., left to 5 right in Fig. 11. The path defined by floor 69a and indented sides 67 may alternatively be characterized as a bent line bisecting the respective pin axes of the multiple punch elements rather than a bent plane comlecting the multiple punch elements.
A fiirther altenzative embodiment of the present invention is shown in Fig.
14.
Floor 369 is angled front-to-back into feed slot 69, i.e., side-to-side in the profile view of Fig. 14 or between closed rear end 69c of feed slot 69 and the opposed open front end.
The angle of floor 369 may slope from low to high in the left-to-right direction in Fig. 14 to provide a large open front end, or be sloped from high to low (not shown) to provide a small open front end.
Several benefits are realized with front-to-back angled floor 369. In Fig. 14, pin 80 is shown in an intermediate position. In this exemplary embodiment, cutting points 21 are syinmetrical meaning that they are at the same axial position of pin 80.
However, for the selected rotational position of pin 80 shown, the cutting points press into the papers (not shown) held in feed slot 69 in a sequence of right to left due to the angled or sloped floor 369. The required force to cut a hole with this symmetrical pin is thereby reduced comparably as with an asyinmetrical pin.
A reduced cutting force can also be achieved if the "V" indentation of sides 67 of Fig. 12 is located off center (not shown) with respect to the pin axis. In such an arrangement, a syinmetrical pin presses each side 67 and then the papers upon the sides 67 in this sequence. These effects are similar to that discussed earlier for angled floor section 18c in coiui.ection with Fig. 2. As suggested by the preceding discussion, points of a punch pin may cut in sequence througll one or a combination of an asyimnetrical pin and/or a non-perpendicular floor of a paper slot with respect to the pin axis. To provide a distinct sequence in pin cutting with a syininetrical pin, the angle of floor 369 slaould preferably be greater than about 5 .
Another benefit of inward angled floor 369 is realized when the punch element is used with feed slot 69 in a vertical orientation. The angle of floor 369 makes the fiill depth of feed slot 69 more visible to a user when angled floor 369 optionally tilts toward a user.
For example, a punclling device may be designed to fit the element in a position rotated 90 clockwise froin the position shown in Fig. 14. The device may be designed for use witli cutting points 21 nonnally facing the user. With this arrangement, feed slot 69 extends and opens upward. Feed slot 69 also angles toward the user t11us ei-diancing the convenience for the user. Optional surrounding stntctures may ftu-ther guide papers toward and within feed slot 69.
In the exemplary embodiment of the present invention in Fig. 14, ceiling 69b is perpendicular to the pin axis. Optionally, ceiling 69b may angle in the same direction as floor 369 to more clearly define an insertion orientation for papers. Or ceiling 69b of Fig.
14, or any other illustrated punch element, may angle away from floor 369, or 69a, to provide a wider opening for feed slot 69 to facilitate inserting papers. In either of these examples, ceiling 69b is not perpendicular to the pin axis.
A still further benefit of angled floor 369 of feed slot 69 is that pin 80 creates an oval hole in papers if the angle off perpendicular from the pin axis is greater than about 5 and less than about 25 . The front-to-back angle of floor 369 may rise upward toward rear closed end 69c as shown in Fig. 14, or floor 369 may altenlatively angle downward toward closed end 69c. The cutting and pull out benefits as described are equal. This pin pull-out force reduction is analogous to the force benefits discussed in coiulection with Fig. 2 and side-to-side angled floor 18c, and with the indentation with sides 67 in the Fig. 12 embodiinent. If ceiling 69b is perpendicular to the pin axis, then the pin pull out force is reduced as discussed in coiulection with Figs. 2 and 12.
Creating the oval hole using angled base 369 also allows a shaip angle while maintaining a compact slot height because there is no cumulative increase in height over a long distance. As with angled section 18c of Fig. 2 or "V" sides 67 of Fig.
12, the angle of base 369 and the associated elevation change are localized to each punch element.
In Figs. 11 and 14, frame 60 includes an outer, upper, lead-in surface 65 that is angled and a lower lead-in surface 63. Upper lead-in surface 65 angles closer to pin 80 when moving toward a tennination at slot 69. In Fig. 14, lead-in surface 65 provides a paper lead-in guide into slot 69. hnportantly, lead-in surface 65 is angled for substantially the ftill height of franie 60 above slot 69. By contrast, conventional punch element frames include such a lead-in surface only as a filleted transition between the paper slot and the outer surface, similar to the area shown in Fig. 11 as the comer where upper lead-in surface 65 joins ceiling 69b. But upper lead-in surface 65 includes an angled or curved profile along most or all of the length of pin 80, unlike conventional designs. Indeed, frame 60 includes lower guide opening 68 and upper guide opening 64. Upper lead-in surface 65 includes a length parallel to the pin axis extending between near the levels of these respective openiulgs 68, 64. Along the length of upper lead-in surface 65, tlie surface angles closer to pin 80 moving from the level of upper guide opening 64 down toward lower guide opening 68. Lead-in surface 65 may alteniatively form an enclosing wall of the enclosed space of fiaine 60 as shown. The upper lead-in stuface 65 tlius provides an effective guide to help position papers within slot 69 at tlie location of the punch element.
In various alternative einbodiments, a low friction coating or material may be added to pins 20 or 80. Pins 20 and 80 are preferably made from hardened steel.
Electroless nickel optioiially coats the pin at least in the areas below groove 25 (Fig. 3) or slot 84 (Fig. 15). hi Fig. 17, plating 300 coats pin 20, 80.
Electroless ilickel plating is also known in the industry as cheinical or autocatalytic nickel plating. Unlike an electroplating (i.e., galvanic plating) teclulique, electroless nickel plating involves chemical nickel plating batlls that work without an extenlal current source. The plating operation is based on the catalytic reduction of nickel ions on the surface being plated. Electroless nickel has one advantage for plating tiny contours of a cutting pin: the coating grows at unifonn speed over the surface of the component. Precise contours can be covered evenly and those surface contours followed fairly precisely.
Subsequent machining is not necessary.
Three common types of electroless nickel coatings are nickel-phosphorus, nickel-boron, and poly alloys. Nickel-phosphorous is the preferred type to plate hole punch coznponents. Typically, electroless nickel plating is deposited by the catalytic reduction of nickel ions with sodiuin hypophosphite in acid baths at pH 4.5-5.0, aiid at a temperature of about 85-95 C. The plating alloy obtained is dependent upon the chemical composition of the solution and the operating conditions. The phosphoitits content significantly influences its chemical and physical properties in both the as-plated condition and after optional heat treatment.
Electroless nickel plating with low phosphorus contents between about 3 % - 7 %
have high wear resistance and high surface hardness (e.g., up to 60 Roclcwell C). A
phosphorus content of about 9 % - 12 % exhibits corrosion and abrasion resistance, and lower surface hardness (about 45-50 Rockwell C). Finally, a phosphoitits content of about 10 % - 13 % produces a coating that is very ductile and corrosion resistant.
The higher phosphorus content plating meets the demands for corrosion resistance against chlorides and simultaneous mechanical stresses.
Thus, electroless nickel when alloyed with or coii.taining phosphorus, exhibits increased wear resistance and chemical resistance. In the application for a paper punch, wear resistance is of interest. Percent phosphorus may range from about 2 % -13 %, inclusive of the upper and lower limits and all ainounts therebetween, with lower ranges tending to manifest better wear resistance aii.d lubricity. In the present hole punch application, the phosphoitiis content is more preferably about 4 % - 6 %.
Other hard low friction surface treatments may be applied to the pin to provide a low friction, low wear interface between steel of the pin and edges of paper.
Electroless niclcel is preferably applied in a thickness of about 0.0001 -0.001 inch, inclusive of the upper and lower limits and all amounts tllerebetween, although other thiclalesses outside this preferred range are possible. The specified range of thiclulesses provide the desired improved properties without increasing the part dimension excessively or causing processing difficulties. More preferably, the electroless nickel on a pin has a plated thiclaless of about 0.0003 - 0.0006 inch.
Once the pin is plated, the electroless nickel provides an interface between the pin body and the edges of the paper at a punched hole. For example, the partial hole of Fig. 2 in papers 51 includes paper edges pressing pin 20. As described above, electroless nickel is a low friction material, especially compared to the bare surface steel of the pin.
Therefore, as plated pin 20, 80 slides within the hole, it moves into the hole and retracts out from the hole with reduced friction. With easier moveinent of plated pin 20, 80, the handle force is redticed and the force of rettull spring 90 or the other spring may be reduced.
Cutting points 21a and 2lb of the pin 20, 80 remain shaip at plating edges or points 320 in Fig. 17. Iii contrast, galvanic plating on a ptulch pin creates a concentration or globule of plating at edges 320, resulting in a rounded or blunted point. The rounded point reduces the effectiveness of the cutting action of the pin. Another advantage of having a hard, IUbrlclous, electroless nickel plating covering the sharp points is reduced wear at those points. The electroless nickel fonns a sharp cutting edge at the cutting points as shown in Fig. 17. Optionally, the pin may be ground or machined to create the shaip cutting points after the plating is applied. Sleeve 11'0 (Figs. 8-10) may also be electroless nickel plated, resulting in cutting end 112 remaining sharp and the sleeve sliding more easily on central pin 120.
It is understood that various changes and modifications of the preferred embodiments described above are apparent to those skilled in the art. Such chailges and modifications can be made witllout departing from the spirit and scope of the present WO 2007/027444 _ 25 _ PCT/US2006/032151 invention. It is therefore intended that such changes and modifications be covered by the following claims.

Claims

1. A hole punch element of a hole punch device, comprising:
a frame guiding a plurality of punch pins along respective pin axes;
wherein the frame includes a slot, and the pin axes extend along a height of the slot from a ceiling of the slot to a floor of the slot; and wherein the slot floor defines an uneven paper path including locally bent portions adjacent to the punch pins.

2. The hole punch element of claim 1, wherein the floor of the slot includes an upper floor portion, a lower floor portion, and an angled portion of the floor between the upper and the lower portions of the floor.

3. The hole punch element of claim 1, wherein the floor of the slot includes an indented portion adjacent to the pin.

4. The hole punch element of claim 1, wherein the paper path of the slot adjacent to the pin is angled off perpendicular from a pin elongate axis by an angle of between about 5° to 25° inclusive.

5. A hole punch device including a punch element, the punch element comprising:
a punch pin having a pin axis;
a frame guiding the punch pin to move along the pin axis, the frame having a slot with a closed end, an opposed open end, a ceiling, and a floor;
wherein the pin axis extends along a height of the slot from the slot ceiling to the slot floor; and wherein the slot floor is angled off perpendicular relative to the pin axis from the closed end of the slot toward the open end of the slot.

6. The punch element of claim 5, wherein the slot floor is angled off perpendicular by an angle of between about 5° to 25°.

7. The punch element of claim 5, wherein the frame includes an anvil cavity, and the pin includes first and second cutting points, and wherein the pin is rotationally positioned so that the first cutting point enters the anvil cavity before the second cutting point.

8. A hole punch element of a hole punch device, comprising:
a punch pin extending along a punch pin axis, wherein the pin includes a cylindrical outer surface and a flat outer surface that connects on two edges with the cylindrical outer surface;

a frame having a hole to slidably receive the punch pin therein and guiding the punch pin to move along the pin axis; and wherein the hole of the frame includes a flat interior surface that contacts the flat outer surface of the pin to hold the pin in a predetermined rotational orientation.

9. The punch element of claim 8, wherein pin includes a "D" shaped transverse cross-sectional area at the flat surface.

10. The punch element of claim 8, wherein the frame includes an anvil cavity and the pin includes first and second cutting points, wherein the pin is rotationally positioned within the frame so that the first cutting point enters the anvil cavity before the second cutting point.

11. A hole punch element of a hole punch device, comprising:
a punch pin having an elongate axis;
a frame guiding a punch pin to traverse along the pin axis, wherein the frame includes a sheet media slot terminating toward a rear of the frame and open toward a front of the frame, and wherein the frame includes a partially enclosed space so that the pin is positioned at a rearward facing opening of the partially enclosed space; and a tie bar engaging the pin at the rearward facing opening.

12. The hole punch element of claim 11, wherein a transverse slot extends into and forms an upper wall within the pin, the frame includes an anvil cavity such that the pin is extendable therein, and the tie bar presses the upper wall of the pin slot to retract the pin from the anvil cavity.

13. The hole punch element of claim 12, wherein the pin includes a cylindrical outer surface transitioning into a flat outer surface, and the frame includes a hole slidably supporting the pin therein, and wherein the hole of the frame includes a flat interior surface that fits against the flat outer surface of the pin to hold the pin in a predetermined rotational orientation.

14. The hole punch element of claim 12, wherein the pin slot includes a ceiling and a return spring presses the ceiling to bias the pin to retract the pin from the anvil cavity.

15. The hole punch element of claim 14, wherein the return spring includes a torsion spring.

16. The hole punch element of claim 14, wherein the ceiling of the pin slot and the upper wall of the pin slot coincide in a common surface.

17. The hole punch element of claim 12, wherein a return spring biases the tie bar away from the anvil cavity.

18. The hole punch element of claim 14, wherein a segment of the return spring contacts the pin to hold the pin in a predetermined rotational position of the pin.

19. A hole punch device including a punch element, the punch element comprising:
a pin having a pin axis and an upper end;
a frame guiding the punch pin along the pin axis, and the frame having an anvil cavity wherein the pin extends into the anvil cavity; and a return spring biasing the pin to retract the pin from the anvil cavity, the return spring including a torsion spring having an upper end that presses the upper end of the pin, and a coil of the return spring that is positioned remotely from the pin.

20. The punch element of claim 19, wherein the coil is positioned within an enclosed space of the frame.

21. The punch element of claim 19, wherein the pin includes a slot and the upper end of the return spring engages the slot.

22. A hole punch device including a punch element, the punch element comprising:
a punch pin including a pin axis;
a frame having a upper guide opening and a lower guide opening wherein the pin extends therethrough so that the frame guides the punch pin for movement along the pin axis; and a lead-in surface of the frame having a length parallel to the pin axis extending between near a level of the upper guide opening to a level of the lower guide opening, wherein the lead-in surface extends closer to the pin starting from the upper guide opening level toward the lower guide opening level.

23. The punch element of claim 22, wherein the lead-in surface terminates in a sheet media slot formed in the frame.

24. The punch element of claim 22, wherein the lead-in surface forms an enclosing wall of an enclosed space formed in the frame.

25. A hole punch device including a punch element, the punch element comprising:
a pin assembly having a pin axis, the pin assembly including a central pin slidable within an expandable sleeve;

a circumferentially inward extending rib formed in the sleeve;
a groove formed in the central pin receiving the rib therein;
a frame guiding the punch pin assembly along the pin axis into and out of an anvil cavity;
wherein a pressing force on the pin assembly moves the pin assembly into the anvil cavity of the frame; and wherein the pressing force causes the rib to slip out of the groove to expand the diameter of the sleeve, and the sleeve diameter contracts upon removal of the pressing force when the rib slips back into the groove.

26. A hole punch device for minimizing punching force having a punch element, the punch element comprising:
a punch pin with at least two cutting points and having an elongate axis;
a support for guiding the punch pin for movement along the elongate axis;
an anvil for holding sheet media; and means for creating sequential cutting action disposed proximate to the punch pin including at least one of (i) a locally angled floor in the anvil proximate the pin, (ii) a local indentation in the anvil proximate the pin, (iii) a keyway in the support that engages a flat in the punch pin to rotationally affix the pin orientation, and (iv) a feed slot in the support containing the anvil wherein the anvil surface slopes toward an opening in the feed slot.

27. The punch element of claim 26, wherein the punch pin includes a pin diameter, and the at least one of the locally angled floor and the local indentation spans a width of about 10% under the pin diameter up to about 5 pin diameters.

28. The punch element of claim 26, wherein the two cutting points are located asymmetrically relative to the pin axis.

29. The punch element of claim 26, wherein the two cutting points include unequal heights.

30. The punch element of claim 26, wherein the two cutting points include a W-shape profile.

31. The punch element of claim 26, wherein the punch element further comprises a coiled torsion spring biasing the punch pin away from the sheet media.

32. The punch element of claim 31, wherein the coiled torsion spring is not coaxially disposed around the punch pin and a coil thereof is located remotely from the punch pin.

33. The punch element of claim 26, wherein the locally angled floor is sloped at an angle of about 5° to 25°.

34. The punch element of claim 26, wherein the means for creating sequential cutting action includes a sleeve having a longitudinal gap and a radially inward-extending rib slidably disposed over the punch pin such that the rib selectively engages the groove.

35. A paper hole punch device, comprising:
a frame guiding a punch pin along a pin axis;
wherein the pin is coated chemically with electroless nickel, the electroless nickel providing an interface between steel of the pin and edges of paper.

36. The hole punch device of claim 35, wherein the pin includes cutting points, and the electroless nickel coats the pin at the cutting points to form a sharp cutting edge at the cutting points.

37. The punch device of claim 35, wherein the electroless nickel includes an alloy of nickel and about 2 to 13 percent inclusive of phosphorus.

38. The punch device of claim 35, wherein the electroless nickel includes a thickness of about 0.0001 to 0.001 inch inclusive.

39. A paper hole punch device, comprising:
a frame guiding a punch pin along a pin axis;
wherein the pin includes a low friction surface treatment providing an interface between steel of the pin and edges of the paper.

40. The hole punch device of claim 39, wherein the surface treatment includes electroless nickel plating.

41. The hole punch device of claim 39, wherein the pin includes cutting points, and the surface treatment includes the cutting points to form a sharp cutting edge at the cutting points.

42. The punch device of claim 40, wherein the electroless nickel includes an alloy of nickel and about 2 to 13 percent inclusive of phosphorus.

43. The punch device of claim 40, wherein the electroless nickel includes a thickness of about 0.0001 to 0.001 inch inclusive.

44. A punch pin of a paper hole punch device, comprising:

a cylindrical body including a first end having sharp cutting points at different heights;
a second end of the cylindrical body having formations for engaging the punch device;

a surface plating that at least covers a portion of the cutting points, wherein the surface plating include electroless nickel of a thickness ranging between about 0.0001 to 0.001 inch inclusive.

45. The punch pin of claim 44, wherein the electroless nickel plating includes an alloy of nickel and about 2 to 13 percent inclusive of phosphorous.

46. The punch pin of claim 44, wherein the electroless nickel plating includes an alloy of nickel and about 4 to 6 percent inclusive of phosphorous.

47. The punch pin of claim 44, wherein the electroless nickel plating includes a thickness of about 0.0003 to 0.0006 inch.

48. The punch pin of claim 44, wherein the electroless nickel plating covering the sharp cutting points does not form globules thereon.