Patent Publication Number: US-8122805-B2

Title: Paper processing tool with three-lever actuation

Description:
BACKGROUND 
     The present invention relates to paper processing tools often used in an office environment for trimming and punching paper or other sheet material. Such paper processing tools known in the prior art are either compact with very little mechanical advantage or alternately are provided with undesirable bulk and/or complexity in order to obtain a greater mechanical advantage, which makes the working operation easier for the user, but increases the amount of desktop/storage space needed and/or increases the number of parts along with manufacturing and assembly costs. 
     SUMMARY 
     In one embodiment, the invention provides a paper processing tool including a base having a receiving area for selectively receiving a sheet of paper. The tool further includes a first lever having a handle portion, the first lever being pivotable relative to the base about a first axis. An intermediate lever is pivotable relative to the base about a second axis in response to movement of the first lever. At least one cutting element is arranged along a cutting plane, the at least one cutting element being configured to selectively engage the sheet of paper. A drive lever is actuable by the intermediate lever to move the at least one cutting element relative to the base. The drive lever is pivotable relative to the base about a third axis parallel to the cutting plane. 
     In another embodiment, the invention provides a paper processing tool including a base defining a sheet insertion area. At least one cutting element is arranged within a cutting plane and movable relative to the base to perform a cutting operation. A first lever is pivotably coupled to the base and rotatable about a first axis, the first lever including a handle portion remote from the first axis. An intermediate lever is pivotably coupled to the base and rotatable about a second axis, the intermediate lever being actuable by the first lever. The first and second axes are positioned on opposite sides of the cutting plane. A drive lever is coupled to the intermediate lever and rotatable about a third axis parallel to the first and second axes. The drive lever is actuable by the intermediate lever to drive the at least one cutting element. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a paper processing tool embodying the invention. 
         FIG. 2  is another perspective view of the paper processing tool of  FIG. 1 . 
         FIG. 3  is a front view of the paper processing tool of  FIG. 1 . 
         FIG. 4  is a cross-section view of the paper processing tool of  FIG. 1  taken along line  4 - 4  of  FIG. 3 . 
         FIG. 5  is a front view of the paper processing tool of  FIG. 1  in an actuated operating condition. 
         FIG. 6  is a cross-section view of the paper processing tool of  FIG. 1  taken along line  6 - 6  of  FIG. 5 , the paper processing tool being in the actuated operating condition. 
         FIG. 7  is a top view of the paper processing tool of  FIG. 1 , having a sheet object inserted therein. 
         FIG. 8  is a perspective view of a second paper processing tool embodying the invention. 
         FIG. 9  is another perspective view of the paper processing tool of  FIG. 8 . 
         FIG. 10  is a front view of the paper processing tool of  FIG. 8 . 
         FIG. 11  is a rear view of the paper processing tool of  FIG. 8 . 
         FIG. 12  is a side view of the paper processing tool of  FIG. 8 . 
         FIG. 13  is a side view of the paper processing tool of  FIG. 8  in an actuated operating condition. 
         FIG. 14  is a cross-section view of the paper processing tool of  FIG. 8 , taken along line  14 - 14  of  FIG. 10 . 
         FIG. 15  is a cross-section view of the paper processing tool of  FIG. 8 , taken along line  15 - 15  of  FIG. 10 . 
         FIG. 16  is a top view of the paper processing tool of  FIG. 8 , having a sheet object inserted therein. 
         FIG. 17  is a perspective view of a paper processing tool similar to the tool shown in  FIGS. 1-7  having an alternate tool element. 
         FIG. 18  is a cross-section view of the paper processing tool of  FIG. 17 , taken along line  18 - 18  of  FIG. 17 . 
     
    
    
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
     DETAILED DESCRIPTION 
       FIGS. 1 and 2  illustrate a paper processing tool  20  operable to perform an operation on one or more sheets of paper or other material. The illustrated paper processing tool  20  is a three-hole punch having a set of punch pins  24 A,  24 B,  24 C positioned adjacent a sheet insertion area  28  and spaced equal distances W apart. The paper processing tool  20  may alternately take the form of another type of apparatus for punching (having more or less than three punch pins), trimming, cutting, etc. In a punching apparatus, tool elements may be similar to the punch pins  24 A-C shown, and in other types of apparatuses, alternate types of tool elements may be provided. In the illustrated embodiment, the paper processing tool  20  is particularly adapted for manual operation by a human hand. In other embodiments, the paper processing tool  20  may be configured for automated actuation. 
     The paper processing tool  20  includes a base  32  having a first end  32 A and a second end  32 B opposite the first end  32 A. Each of the punch pins  24 A-C is supported for reciprocable movement relative to the base  32  along a respective axis D 1 , D 2 , D 3 . The punch pins  24 A-C are substantially aligned, such that a cutting plane D 4  ( FIG. 7 ) contains each of the punch pin axes D 1 , D 2 , D 3 . The base  32  includes a punch frame or housing  36  for each punch pin  24 A-C which mounts the punch pins  24 A-C to the base  32  and guides the movement of the punch pins  24 A-C. One or more of the punch frames  36  may be movable within the cutting plane D 4  to vary the spacing between the punch pins  24 A-C. A biasing element such as a coil spring  40  is engaged with each of the punch pins  24 A-C and with the corresponding punch frame  36 . Each punch frame  36  defines an insertion slot  42  positioned along the sheet insertion area  28 . The coil springs  40  bias the punch pins  24 A-C generally upward out of the insertion slots  42 . 
     The paper processing tool  20  further includes a first lever  46 . The first lever  46  is an input member of the paper processing tool  20  and as such, is configured to receive an input force incident on the paper processing tool  20 . The first lever  46  includes an attachment portion  50  mounted to the base  32 , and the first lever  46  is pivotable relative to the base  32  about a first axis A. The first axis A is located adjacent the first end  32 A of the base  32 . The first axis A is defined by an axle or pin  54  and by coaxial holes in the attachment portion  50  and the punch frame  36  nearest the first end  32 A of the base  32 . The pin  54  is axially positioned by a retaining element such as an E-ring  56  on each end. The first lever  46  includes a handle portion  58  remote from the attachment portion  50  and the first axis A. The handle portion  58  is configured to receive a manual input from a user&#39;s hand, although the first lever  46  may be actuated in an automated manner in some embodiments. 
     A sliding joint  62  is provided between the first lever  46  and an intermediate lever  64 . The sliding joint  62  includes a pin  62 A movable with the intermediate lever  64  and a slot  62 B in the first lever  46 . The pin  62 A is axially positioned by a retaining element such as an E-ring  65  on each end. The sliding joint  62  is located adjacent the attachment portion  50  on the first lever  46 . On the intermediate lever  64 , the sliding joint  62  is located adjacent a first end  66 , which is opposite a second end  68  of the intermediate lever  64 , where the intermediate lever  64  is coupled to the base  32 . The intermediate lever  64  is pivotable relative to the base  32  about a second axis B. The second axis B is located adjacent the second end  32 B of the base  32 . The second axis B is defined by an axle or pin  72  and by coaxial holes in the second end  68  of the intermediate lever  64  and the punch frame  36  nearest the second end  32 B of the base  32 . The pin  72  is axially positioned by a retaining element such as an E-ring  74  on each end. The intermediate lever  64  is a transmission member configured to receive a force from the first lever  46  and transmit an equal or greater force to the punch pins  24 A-C through at least one additional transmission member. 
     The illustrated intermediate lever  64  includes two spaced-apart parallel links  64 A,  64 B and a drive member such as a drive pin  78  extending between the links  64 A,  64 B at a location between the first and second ends  66 ,  68 . In the illustrated embodiment, the drive pin  78  is substantially centered between the first and second ends  66 ,  68  of the intermediate lever  64 . The drive pin  78  is axially positioned relative to the links  64 A,  64 B by a retaining element such as an E-ring  80  on each end. In the illustrated embodiment, the drive pin  78  includes a roller  78 A having a rounded or cylindrical drive surface  84  configured to engage a drive lever  88 . In some embodiments, the roller  78 A spins on a shaft  78 B of the drive pin  78 , such that the roller  78 A is pivotably coupled to the links  64 A,  64 B. 
     The drive lever  88  extends between the first end  32 A and the second end  32 B of the base  32 . In the illustrated embodiment, the drive lever  88  is coupled to a first end plate  92  of the base  32  at the first end  32 A and to a second end plate  94  of the base  32  at the second end  32 B. The drive lever  88  is positioned relative to the base  32  by a pin  98  at each of the first and second end plates  92 ,  94  or by a single shaft (not shown). The pins  98  define a third axis C about which the drive lever  88  is pivotable relative to the base  32 . The third axis C extends between the first and second ends  32 A,  32 B of the base and is substantially perpendicular to both of the first and second axes A, B, which are substantially parallel with each other. The drive lever  88  is configured to engage and actuate the punch pins  24 A-C as described in further detail below. 
     As shown in at least  FIGS. 4 and 6 , the drive lever  88  includes a first cam surface  102  engageable with the intermediate lever  64  and a second cam surface  106  ( FIG. 6 ) engageable with the punch pins  24 A-C. The first cam surface  102  includes a rounded profile configured to be engaged and driven by the drive surface  84  of the drive pin  78 . The two rounded surfaces (i.e., the drive surface  84  of the drive pin  78  and the first cam surface  102 ) define a sliding cam engagement or sliding joint between the intermediate lever  64  and the drive lever  88 . In some embodiments, the drive pin  78  rolls on the drive lever  88  or an additional rolling member (not shown) is provided between the drive pin  78  and the drive lever  88  so that a rolling cam engagement or rolling joint is provided. The second cam surface  106  of the drive lever  88  is configured to engage an upper drive surface  110 A-C of each of the punch pins  24 A-C ( FIGS. 4 and 6 ). The second cam surface  106  includes a rounded profile engaged with the upper drive surfaces  110 A-C, which are substantially flat in the illustrated embodiment. The second cam surface  106  of the drive lever  88  actuates all three punch pins  24 A-C for synchronized movement of the punch pins  24 A-C (within the cutting plane D 4 ) towards and into engagement with a sheet object  114  ( FIG. 7 ) in the insertion area  28 . 
     In other embodiments, more or fewer than three punch pins similar to the punch pins  24 A-C are provided, and the second cam surface  106  of the drive lever  88  engages the punch pins  24 A-C for synchronized movement thereof. Furthermore, the punch pins  24 A-C may be actuated sequentially by the drive lever  88 . In yet other embodiments, the paper processing tool  20  is provided with one or more alternate tool elements instead of the punch pins  24 A-C as illustrated. For example, a planar cutting or trimming blade (having a linear or non-linear profile) may be actuable by the drive lever  88  in a manner similar to that described above with respect to the punch pins  24 A-C. 
     In operation, the sheet object  114  to be processed (e.g., cut, trimmed, punched) is inserted into the insertion area  28  along an insertion direction perpendicular to the cutting plane D 4 . A force is then applied to the handle portion  58  of the first lever  46 . The first lever  46  rotates relative to the base  32  about the first axis A. The force applied to the first lever  46  is multiplied as it is transferred to the intermediate lever  64  via the sliding joint  62 . During transfer between the first lever  46  and the intermediate lever  64 , the handle portion  58  moves towards the base  32  and the pin  62 A slides within the slot  62 B. As the pin  62 A slides in the slot  62 B toward the first axis A, the mechanical advantage or force multiplication between the first lever  46  and the intermediate lever  64  is increased due to the increased lever arm distance between the handle portion  58  and the pin  62 A. The sliding joint  62  provides a variable mechanical advantage by allowing the point of contact between the first lever  46  and the intermediate lever  64  (defined by the point on the slot  62 B that is in driving contact with the pin  62 A) to move relative to the first axis A. 
     As force is transmitted from the first lever  46  to the intermediate lever  64  through the sliding joint  62 , the first end  66  of the intermediate lever  64  moves towards the base  32  as the intermediate lever  64  rotates about the second axis B. The drive pin  78  moves towards the base  32  such that the drive surface  84  engages the first cam surface  102  of the drive lever  88 . As the intermediate lever  64  rotates about the second axis B, the drive pin  78  drives the drive lever  88  to rotate about the third axis C. Some amount of sliding occurs between the cylindrical drive surface  84  of the drive pin  78  and the rounded profile of the first cam surface  102  as the drive lever  88  is rotated generally downward towards the base  32 . Alternately or in addition, sliding may occur between the drive pin  78  and each of the first and second links  64 A,  64 B of the intermediate lever  64 . In some embodiments, some amount of rolling occurs between the drive pin  78  and the drive lever  88 , whether directly between the drive surface  84  and the first cam surface  102  or alternately, through an additional roller (not shown) therebetween. 
     As the drive lever  88  rotates towards the base  32  under force from the intermediate lever  64 , the second cam surface  106  of the drive lever  88  actuates the punch pins  24 A-C to drive the punch pins  24 A-C along their respective axes D 1 , D 2 , D 3 . In the illustrated embodiment, the punch pins  24 A-C are actuated synchronously from fully inoperative positions ( FIG. 4 ) outside of the insertion slots  42  to fully operative positions ( FIG. 6 ) in which the punch pins  24 A-C extend entirely through the insertion slots  42 . In some embodiments, the punch pins  24 A-C are actuated asynchronously. The punch pins  24 A-C remain in the cutting plane D 4  ( FIG. 7 ) at all times. 
     In order to generate a large mechanical advantage for performing the desired action on the sheet object  114  within an efficient and small size or “foot print” (i.e., the area of the base  32 ), the paper processing tool  20  includes a specific arrangement with respect to the levers  46 ,  64 ,  88  and the respective axes of rotation A, B, C. The first axis A is positioned just outside the punch pin  24 A adjacent the first end  32 A of the base  32 . Specifically, the first axis A is positioned a distance X between about 9 percent and about 12 percent of the distance W (between adjacent punch pins  24 A-C) from the first punch pin  24 A. In the illustrated embodiment, the first axis A is positioned a distance X that is about 10 percent of the distance W from the first punch pin  24 A. Furthermore, the second axis B is positioned just within the punch pin  24 B adjacent the second end  32 B of the base  32 . Specifically, the second axis B is positioned a distance Y between about 9 percent and about 12 percent of the distance W from the second punch pin  24 B. In the illustrated embodiment, the second axis B is positioned a distance Y that is about 10 percent of the distance W from the second punch pin  24 B. The first and second axes A, B are fixed pivots, which are fixed relative to the base  32 . As mentioned above, the point of contact between the slot  62 B and the pin  62 A of the sliding joint  62  is a variable, non-fixed pivot that increases the mechanical advantage of the paper processing tool  20  during the downward stroke of the first lever  46 . The paper processing tool  20  has a mechanical advantage of at least  15  between the force applied at the first lever  46  and the force applied to the sheet object  114  by the punch pins  24 A-C. The particular arrangement illustrated and described above generates a mechanical advantage of about  20  between the force applied at the first lever  46  and the force applied to the sheet object  114  by the punch pins  24 A-C. 
     Furthermore, and as shown in  FIGS. 4 and 7 , the punch pins  24 A-C define a cutting length L (from the first punch pin  24 A to the second punch pin  24 B). As illustrated, the cutting length L is equal to twice the spacing distance W. In other embodiments, the cutting length L may be defined by the overall or cumulative length of a continuous blade or alternate configurations of spaced apart cutting elements. The first axis A is spaced apart from the second axis B by a distance Z ( FIGS. 1 and 7 ) equal to between about 35 percent and about 115 percent of the cutting length L. In the illustrated embodiment, the distance Z between the first axis A and the second axis B is equal to about 100 percent of the cutting length L. 
     A paper processing tool  220  according to another embodiment of the invention is illustrated in  FIGS. 8-15 . The paper processing tool  220  is operable to perform an operation on one or more sheets of paper. The illustrated paper processing tool  220  is a three-hole punch having a set of punch pins  224 A,  224 B,  224 C positioned adjacent a sheet insertion area  228  and spaced equal distances W 2  apart. Thus, an overall cutting length L 2  is defined between the first punch pin  224 A and the second punch pin  224 B that is equal to twice the spacing distance W 2 . The paper processing tool  220  may alternately take the form of another type of apparatus for punching (having more or less than three punch pins), trimming, cutting, etc. In a punching apparatus, tool elements may be similar to the punch pins  224 A-C shown, and in other types of apparatuses, alternate types of tool elements may be provided. In the illustrated embodiment, the paper processing tool  220  is particularly adapted for manual operation by a human hand. In other embodiments, the paper processing tool  220  may be configured for automated actuation. 
     The paper processing tool  220  includes a base  232  having a first end  232 A and a second end  232 B opposite the first end  232 A. Each of the punch pins  224 A-C is supported for reciprocable movement relative to the base  232  along a respective axis D 11 , D 12 , D 13 . The punch pins  224 A-C are substantially aligned, such that a cutting plane D 14  ( FIGS. 12-16 ) contains each of the punch pin axes D 11 , D 12 , D 13 . The base  232  includes a punch frame or housing  236  for each punch pin  224 A-C which mounts the punch pins  224 A-C to the base  232  and guides the movement of the punch pins  224 A-C. One or more of the punch frames  236  may be movable within the cutting plane D 14  to change the spacing between the punch pins  224 A-C. Each punch frame  236  defines an insertion slot  242  positioned along the sheet insertion area  228 . One or more biasing elements  240  bias the punch pins  224 A-C generally upward out of the insertion slots  242  as described in further detail below. 
     The paper processing tool  220  further includes a first lever  246 . The first lever  246  includes a first link  246 A, a second link  246 B, and a pair of connecting links  246 C extending between the first link  246 A and the second link  246 B. The first lever  246  is an input member of the paper processing tool  220  and as such, is configured to receive an input force incident on the paper processing tool  220 . The first and second links  246 A,  246 B of the first lever  246  are substantially identical mirror images of one another and each includes an attachment portion  250  mounted to the base  232 . The entire first lever  246  is pivotable relative to the base  232  about a first axis A 2 . The first axis A 2  is defined by an axle or pin  254  engaged with each attachment portion  250 . The first axis A 2  is further defined by two pairs of coaxial holes, one hole through each attachment portion  250  and one hole through the base  232  immediately adjacent each attachment portion  250 . The first lever  246  includes a handle portion  258  remote from the attachment portion  250  and the first axis A 2 . The handle portion  258  is configured to receive a manual input from a user&#39;s hand, although the first lever  246  may be actuated in an automated manner in some embodiments. In the illustrated embodiment, the handle portion  258  includes the connecting links  246 C and portions of both the first and second links  246 A,  246 B (opposite the attachment portions  250 ). 
     One or more sliding joints  262  are provided between the first lever  246  and an intermediate lever  264 . In the illustrated embodiment, both the first and second links  246 A,  246 B of the first lever  246  are coupled to the intermediate lever  264  via sliding joints  262 . Similar to the first lever  246 , the intermediate lever  264  includes a pair of spaced-apart, parallel links. The intermediate lever  264  includes a first link  264 A and a second link  264 B. The first and second links  264 A,  264 B are coupled together as described in further detail below. 
     Each sliding joint  262  includes a pin  262 A movable with the corresponding intermediate lever  264  and a slot  262 B in the corresponding link  246 A,  246 B of the first lever  246 . The sliding joints  262  are located adjacent the attachment portions  250  on the first and second links  246 A,  246 B of the first lever  246 . On the intermediate lever  264 , the sliding joints  262  are located adjacent a first end  266  of each of the links  264 A,  264 B, which is opposite a second end  268  of each of the links  264 A,  264 B of the intermediate lever  264  where the intermediate lever  264  is coupled to the base  232 . The intermediate lever  264  is pivotable relative to the base  232  about a second axis B 2 . The second axis B 2  is defined by an axle or pin  272  engaged with the second ends  268  of the first and second links  264 A,  264 B and by coaxial holes in the second ends  268  and axially aligned slots  276  in the base  232 . The intermediate lever  264  is a transmission member configured to receive a force from the first lever  246  and transmit an equal or greater force to the punch pins  224 A-C through at least one additional transmission member. 
     The intermediate lever  264  includes not only the first and second links  264 A,  264 B, but also a drive member such as a drive pin  278  extending between the first and second links  264 A,  264 B at a location between the respective first and second ends  266 ,  268 . In the illustrated embodiment, the drive pin  278  is substantially centered between the first and second ends  266 ,  268  of each of the first and second links  264 A,  264 B of the intermediate lever  264 . The drive pin  278  includes a rounded or cylindrical drive surface  284  configured to engage one or more drive levers  288 . In some embodiments, the drive pin  278  may include a roller similar to the roller  78 A of the paper processing tool  20  illustrated in  FIGS. 1-7 . 
     In the illustrated embodiment, three drive levers  288  are actuable by the drive pin  278 . In the illustrated embodiment, each drive lever  288  is coupled to a respective one of the punch frames  236 . The drive levers  288  are pivotably coupled to the punch frames  236  (and thus, relative to the base  232 ) by respective pins  298 . The pins  298  define a third axis C 2  about which the drive levers  288  are pivotable relative to the base  232 . The third axis C 2  is substantially parallel to both of the first and second axes A 2 , B 2 . The third axis C 2  is also substantially parallel to the cutting plane D 14 . The drive levers  288  are configured to engage and actuate the punch pins  224 A-C as described in further detail below. 
     As shown in  FIGS. 8-11 , each of the drive levers  288  includes a pair of flange portions  302  and a connecting portion  306 , each of the flange portions  302  having an opening formed therein to receive the drive pin  278 . The drive pin  278  is engaged with the drive levers to rotate the drive levers  288  about the third axis C 2  and reciprocate the punch pins  224 A-C along their respective axes D 11 , D 12 , D 13  within the cutting plane D 14 . A secondary drive pin  308  extends between each pair of flange portions  302 . The punch pins  224 A-C are mounted to respective punch blocks  310  ( FIG. 15 ), each of which includes a slot  310 A in which one of the secondary drive pins  308  is engaged. The punch pins  224 A-C are directly connected to the punch blocks  310  (in the sense that each punch pin  224 A-C is fixed relative to the respective punch block  310 ). In the illustrated embodiment, a single set screw  310 B couples the punch pins  224 A-C to the respective punch blocks  310 . All three of the drive levers  288  are actuated by the drive pin  278  so that the drive levers  288  actuate all three punch pins  224 A-C for synchronized movement of the punch pins  224 A-C (within the cutting plane D 14 ) towards and into engagement with a sheet object  314  in the insertion area  228 . In some embodiments, the drive levers  288  actuate the punch pins  224 A-C sequentially. 
     In other embodiments, more or fewer than three punch pins similar to the punch pins  224 A-C are provided, and one or more drive levers  288  engage the punch pins  224 A-C for synchronized movement thereof. In yet other embodiments, the paper processing tool  220  is provided with one or more alternate tool elements (see  FIGS. 17-19 ) instead of the punch pins  224 A-C as illustrated in  FIGS. 8-16 . 
     In operation, the sheet object  314  to be processed (e.g., cut, trimmed, punched) is inserted into the insertion area  228  along an insertion direction perpendicular to the cutting plane D 14 . A force is then applied to the handle portion  258  of the first lever  246 . The first lever  246  rotates relative to the base  232  about the first axis A 2 . The springs  240  are torsion springs in the illustrated embodiment and each spring  240  is wound around a respective one of the pins  254  connecting the first lever  246  to the base  232 . An extending leg  240 A of each spring  240  rests against the adjacent sliding joint pin  262 A and also upon a pin  292  extending from an interior side of the adjacent link  246 A,  246 B such that the extending leg  240 A is trapped between the pins  262 A,  292 . An opposite extending leg  240 B of each of the springs  240  rests against the base  232  such that rotation of the first lever  246  (moving the handle portion  258  towards the base  232 ) loads the springs  240 . The springs  240  are sufficient to hold the first lever  246  in the fully inoperative or “up” position (see  FIG. 12 , for example) at rest, but is easily overcome by the user to operate the paper processing tool  220 . 
     The force applied to the first lever  246  is multiplied as it is transferred to the intermediate lever  264  via the sliding joints  262 . During transfer between the first lever  246  and the intermediate lever  264 , the handle portion  258  moves towards the base  232  and the pins  262 A slide within the slots  262 B. As the pins  262 A slide in the slots  262 B toward the first axis A 2 , the mechanical advantage or force multiplication between the first lever  246  and the intermediate lever  264  is increased due to the increased lever arm distance between the handle portion  258  and the axis of the pins  262 A. The sliding joints  262  provide a variable mechanical advantage by allowing the point of contact between the first lever  246  and the intermediate lever  264  (defined by the point on the slot  262 B that is in driving contact with the pin  262 A) to move relative to the first axis A 2 . 
     As force is transmitted from the first lever  246  to the intermediate lever  264  through the sliding joints  262 , the first end  266  of the intermediate lever  264  moves towards the base  232  as the intermediate lever  264  rotates about the second axis B 2 . The drive pin  278  moves towards the base  232  such that the drive surface  284  engages the drive levers  288 . As the intermediate lever  264  rotates about the second axis B 2 , the drive pin  278  drives the drive levers  288  to rotate about the third axis C 2 . The generally downward (towards the base  232 ) rotation of the drive levers  288  causes some amount of sliding contact between the cylindrical drive surface  284  of the drive pin  278  and the openings in the drive levers  288 . Alternately or in addition, the drive pin  278  can rotate with the drive levers  288 , and some amount of sliding may occur between the drive pin  278  and each of the first and second links  264 A,  264 B of the intermediate lever  264 . In some embodiments, rolling contact occurs between the drive pin  278  and the drive levers  288  and/or between the drive pin  278  and the intermediate lever  264 , for example by one or more roller bearings or other rolling elements (not shown). 
     As the drive levers  288  rotate towards the base  232  under force from the intermediate lever  264 , the secondary drive pins  308  exert a downward force upon the slots  310 A in each of the punch blocks  310  to drive the punch pins  224 A-C along their respective axes D 11 , D 12 , D 13 . The slots  310 A allow the secondary drive pins  308  to slide relative to the punch blocks  310 , which is necessary to have both pivotal movement of the drive levers  288  and reciprocal movement of the punch blocks  310  and the punch pins  224 A-C. In the illustrated embodiment, the punch pins  224 A-C are actuated synchronously from fully inoperative positions ( FIG. 12 ) outside of the insertion slots  242  to fully operative positions ( FIG. 13 ) in which the punch pins  224 A-C extend entirely through the insertion slots  242 . In some embodiments, the punch pins  224 A-C are actuated asynchronously. The punch pins  224 A-C remain in the cutting plane D 14  at all times. 
     In order to generate a large mechanical advantage for performing the desired action on the sheet object  314  within an efficient and small size or “foot print” (i.e., the area of the base  232 ), the paper processing tool  220  includes a specific arrangement with respect to the levers  246 ,  264 ,  288  and the respective axes of rotation A 2 , B 2 , C 2 . The first axis A 2  is positioned on one side of the cutting plane D 14 , and the second axis B 2  is positioned on an opposite side of the cutting plane D 14 . Specifically, the first axis A 2  is positioned a distance X 2  equal to between about 35 percent and about 45 percent of the distance W 2  (i.e., half the cutting length L 2 ) rearward of the cutting plane D 14 . In the illustrated embodiment, the first axis A 2  is positioned a distance X 2  equal to about  40  percent of the distance W 2  rearward of the cutting plane D 14 . Furthermore, the second axis B 2  is positioned a distance Y 2  equal to between about 30 percent and about 45 percent of the distance W 2  forward of the cutting plane D 14  (in a direction from which the sheet object  314  is inserted). In the illustrated embodiment, the second axis B 2  is positioned a distance Y 2  equal to about  38  percent of the distance W 2  forward of the cutting plane D 14 . Typically, prior art devices have not located a pivot axis forward of the cutting plane as it presents a restriction in access to the sheet insertion area  228 , opting instead to provide a small mechanical advantage or a large footprint area of the device. By locating the second axis B 2  forward of the cutting plane D 14 , the paper processing tool  220  suffers only a slight restriction in accessibility to the sheet insertion area  228  while providing an exceptional mechanical advantage for the small size of the footprint area. 
     The first axis A 2  is a fixed pivot, which is fixed relative to the base  232 , and the second axis B 2  is a movable axis, which is not fixed relative to the base  232 . As mentioned above, the points of contact between the slots  262 B and the pins  262 A of the sliding joints  262  define a variable, non-fixed pivot that increases the mechanical advantage of the paper processing tool  220  during the downward stroke of the first lever  246 . The paper processing tool  220  has a mechanical advantage ratio of at least 15 between the force applied at the first lever  246  and the force applied to the sheet object  314  by the punch pins  224 A-C. The particular arrangement illustrated and described above generates a mechanical advantage ratio of about 20 between the force applied at the first lever  246  and the force applied to the sheet object  314  by the punch pins  224 A-C. 
     Furthermore, in the illustrated embodiment, the cutting length L 2  (from the first punch pin  224 A to the second punch pin  224 B) is equal to twice the spacing distance W 2 . In other embodiments, the cutting length L 2  may be defined by the overall or cumulative length of a continuous blade or alternate configurations of spaced apart cutting elements. The first axis A 2  is spaced apart from the second axis B 2  by a distance Z 2  equal to between about 35 percent and about 115 percent of the cutting length L 2 . In the illustrated embodiment, the distance Z 2  between the first axis A 2  and the second axis B 2  is equal to about  40  percent of the cutting length L 2 . 
       FIGS. 17-18  illustrate a paper processing tool  320  similar in many aspects to the tool  20  illustrated in  FIGS. 1-7 . Like reference characters are used where applicable. However, in place of the punch pins  24 A-C, the paper processing tool  320  of  FIGS. 17-18  includes a trimmer blade  324  arranged along the cutting plane D 4  (not shown). The trimmer blade  324  has a cutting length L 3  and is actuated to reciprocate in the same manner as described above with reference to the punch pins  24 A-C of the paper processing tool  20 . For example, the drive lever  88  actuates upper surfaces  110 A-C of respective mounting blocks or blade extensions  328 . Trimmer guide frames  336  are slotted to allow passage of the trimmer blade  324  therethrough. The trimmer blade  324  is angled (i.e., non-parallel) with respect to the horizontal base  32  and interacts with a lower stationary blade  340  to shear sheet material when the first lever  46  is depressed. 
     The geometry and function of the first lever  46 , the intermediate lever  64 , the sliding joint  62 , and the drive lever  88  is unchanged from the paper processing tool  20  of  FIGS. 1-7 , and thus, the same advantages are provided. Although the cutting length L 3  of the trimmer blade  324  is illustrated as being relatively longer than the cutting length L of the paper processing tool  20  of  FIGS. 1-7 , it should be noted that the cutting length L 3  may be longer or shorter than shown in  FIG. 18 . For example, the cutting length L 3  can be substantially equal to the cutting length L of the paper processing tool  20  of  FIGS. 1-7  such that the ratios relating the distances X, Y, and Z thereto are substantially the same as described above with respect to the paper processing tool  20  of  FIGS. 1-7 . Where dimensions are related to the spacing distance W, it is understood that they may be considered as being related to one half of the cutting length L or L 3 . 
     Thus, the invention provides, among other things, a compact paper processing tool with a large mechanical advantage, which includes a first lever, an intermediate lever, and a drive lever. Each lever rotates relative to the base about a separate axis, and the axis of the drive lever is parallel to a cutting plane of the paper processing tool. Various features and advantages of the invention are set forth in the following claims.