Abstract:
Sheet cutter minimizing friction occurred between a slider and a guide rail while transferring the slider along the guide rail in a high linearity. Each of the slider and the guide rail has either a convex or a concave portion up and down to fit each other. In cutting processes only the convex and concave portions are made abutted each other contributing to minimization of the friction and smooth transferability of the slider in a high linearity.

Description:
[0001]     BACKGROUND OF THE INVENTION  
         [0002]     1. Field of the Invention  
         [0003]     This invention relates to cutters for sheet material mainly papers, and more particularly, to a sheet cutter cutting the sheet material by positioning thereof by means of a paper-holding ruler.  
         [0004]     2. Description of the Related Art  
         [0005]     Japanese Patent Application Laid-Open No 11-33978 (hereinafter D1) discloses a sheet cutter in which a slider is movably installed to a guide rail T-shaped in section and provided on a base in such a manner that both a guide groove and a guide surface formed on a guide member of the slider are made fit to the guide rail. Japanese Patent Application Laid-Open No. 6-262586 (hereinafter D2) further relates to a sheet cutter for paper and discloses that a fitting groove for a cutter sheet is formed parallel with a rail provided on a base, and a cutter sheet presser is removably provided at the end of the fitting groove contributing to an easy exchange of the cutter sheet. Japanese Patent Application Laid-open No. 11-309695 (hereinafter D3) then relates to a lock mechanism in a paper-holding ruler and discloses that the paper-holding ruler is movably provided on a guide rail (either concave or convex form) formed on an installation table orthogonal to a cutter rail. A lock member such as a pressure plate is pressed onto the guide rail with a lever provided with the paper-holding ruler thereby locking the paper-holding ruler in a position where a user selects. Lastly, Japanese Paten Application Laid-open No. 5-337879 (hereinafter D4) relates to a sheet cutter for paper and discloses that a guiding foot integrally and orthogonally provided with a paper-positioning member is movably fit to a groove on a paper-seating table orthogonal to a rail. A lock member is pressed onto the interior wall of the groove by operating a lever provided with the paper-positioning member thereby locking the paper-positioning member in optional positions.  
         [0006]     In D1, both the guide groove and guide surface formed on the guide member of the slider are made fit to the T-sectional guide rail so that the slider and the guide rail are abutted nearly in a whole surface making the slider guided in a high linearity. Because its contact surface rate between the slider and the guide rail is high in D1 as discussed above, early abrasion therebetween may occur. In D2, the cutter sheet presser is removably provided at the end of the fitting groove so that it helps relatively easy replacement of the cutter sheet. There however needs further operational improvement regarding how to install the cutter sheet into the fitting groove. In D3, the paper-holding ruler is movably provided on the guide rail formed on the installation table, and the paper-holding ruler is made locked with the lever. In this structure, it is not however applicable to lock the paper-holding ruler where the ruler is placed out of the installation table. In D4, the guiding foot integrally and orthogonally provided with the paper-positioning member is movably fit to the groove formed on the paper-seating table. Since the paper-positioning member is made locked with the lever provided therewith, as same as the D3, it is not applicable where placed out of the paper-seating table.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention has been made in light of the disadvantages described above, and it is a first object of the present invention to provide a sheet cutter with a slider installed to a guide rail minimizing abrasion resistance between the slider and the guide rail and enabling to guide the slider in a high linearity on the guide rail. It is further a second object of the present invention to provide the sheet cutter in which a cutter mat can be easily installed to or removed from a fitting groove on a base. It is still further a third object of the present invention to provide the sheet cutter in which a paper-holding ruler can be locked on the base even if it is placed out of the base. Hereinafter described some aspects of the present invention to achieve the above objects.  
         [0008]     In a first aspect, a sheet cutter comprises: a base; a guide rail provided on the base; and a slider provided with a cutter and movably installed on the guide rail, in which each of the slider and the guide rail has either a convex or a concave portion up and down so as to fit each other. Thus constructed, only the convex and concave portions are made abutted each other in cutting processes so as to minimize friction occurred between the slider and the guide rail. The slider can be also moved smoothly along the guide rail in a high linearity.  
         [0009]     In a second aspect according to the first aspect, two contacts are additionally provided from side to side between the slider and the guide rail, and these contacts are made detached from each other in cutting processes. Because the slider and the guide rail come into contact with not only at the convex and the concave portions provided up and down but also at the two additional contacts provided from side to side, the slider stays with the guide rail even if the sheet cutter is leant in its position. In cutting processes, however, only the convex and concave portions are made contact each other whereby the slider and the guide rail have less friction therebetween.  
         [0010]     In a third aspect, a sheet cutter comprises: a base; a guide rail provided on the base; a slider provided with a cutter and movably installed on the guide rail; and a cutter mat placed on a top surface of the base and installed in a fitting groove formed along the guide rail. A guide portion is provided near the fitting groove so as to guide the cutter mat toward the fitting groove. Thus constructed, when exchanging the cutter mat, a user is only required to place the cutter mat at the guide portion. Once placed at the guide portion, the cutter mat is guided by its own weight into the fitting groove thus simplifying its exchange.  
         [0011]     In a forth aspect according to the third aspect, a rotary end-holder is provided at at least one end of the fitting groove so as to hold the cutter mat in the fitting groove. Even in case the sheet cutter is leant, the cutter mat is still held in the fitting groove by means of the rotary end-holder.  
         [0012]     In a fifth aspect according to the third aspect, an end fastener is also provided at one end of the fitting groove fastening one end of the cutter mat while the rotary end-holder is concurrently provided at the other end of the fitting groove retaining the other end of the cutter mat. The cutter mat can be yet surely retained in the fitting groove, and the exchange of the cutter mat is again simplified.  
         [0013]     In a sixth aspect, a sheet cutter comprises: a base; a guide rail provided on the base; a slider provided with a cutter and movably installed on the guide rail; and a paper-holding ruler provided on a top surface of the base and installed in guide grooves orthogonally provided to the guide rail. The paper-holding ruler has foot portions orthogonally provided thereto thus making thereof movable along the guide grooves. A positioning means is further provided between the foot portions (and the guide grooves) enabling the paper-holding ruler placed in a given position. Thus constructed, even in case the paper-holding ruler is applied out of the top surface of the base, the foot portions are surely made fixed to the guide grooves by means of the positioning means.  
         [0014]     In a seventh aspect according to the sixth aspect, the positioning means comprises: concavities formed on either the foot portions or the base; a protrusion that can be engaged with or removed from the concavities; and a protrusion operating member keeping the protrusion engaged. Thus constructed, it makes easier for the protrusion to be engaged with or removed from the concavities by simply operating the protrusion operation member.  
         [0015]     In an eighth aspect according to the sixth and seventh aspects, the guide grooves concave in section are formed in that the bottom closing width thereof are made wider than the top opening width thereof so that the foot portions are held in the guide grooves. Irrespective of whether the sheet cutter is used or unused, the paper-holding ruler can surely stay with the guide grooves.  
         [0016]     In a ninth aspect according to the sixth aspect, the positioning means comprises: concavities provided on either the foot portions or the top surface of the base; and a protrusion integrally formed with a plate spring and energized toward the concavities. Because the plate spring has the protrusion, the positioning means needs to have fewer components thereby simplifying the structure thereof.  
         [0017]     In a tenth aspect according to the sixth aspect, the positioning means comprises: concavities provided on either the foot portions or a top surface of the base; and a protrusion integrally formed on either the foot portions or the top surface of the base and energized toward the concavities. Since the concavities and the protrusion are both integrally formed on either the foot portions or the base, it succeeds to reduce the number of components that the positioning means requires. The positioning means can be accordingly constructed by simply installing the foot portions into the base.  
         [0018]     In an eleventh aspect according to the sixth aspect, the positioning means comprises: concavities provided on the foot portions; and a protrusion provided on the base and movable toward the concavities through a linkage with an operation member. Comparing with the positioning means having the energizing members such as the plate spring, the foot portions can fix further stably to the base.  
         [0019]     In a twelfth aspect according to the sixth aspect, the positioning means comprises: concavities formed on a top surface of the base; and a protrusion energized toward the concavities by means of an energizing means. Since the positioning means is installed into the foot portions, the structure thereof is further simplified.  
         [0020]     In a thirteenth aspect according to any one of the above aspects, the sheet cutter may have a handle so as to improve portability. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is a perspective view of a sheet cutter according to the present invention in which a paper-holding ruler is fixed in a given position, and a cutter mat is about to install into a fitting groove;  
         [0022]      FIG. 2  is a top plan view of the sheet cutter according to the present invention in which the paper-holding ruler is fixed out of an installation table of a base;  
         [0023]      FIG. 3  is a back view of the sheet cutter according to the present invention;  
         [0024]      FIG. 4  is a cross sectional view taken along line X-X of  FIG. 2  where the paper-holding ruler is fixed on the installation table;  
         [0025]      FIG. 5A  is an enlarged view of a circular region D in  FIG. 4 , and  FIG. 5B  is a schematic diagram showing a slide portion between a slider and a guide rail;  
         [0026]      FIG. 6  is a schematic diagram showing another embodiment of the slide portion between the slider and the guide rail;  
         [0027]      FIG. 7A  is an enlarged view of a circular region A in  FIG. 1 , and  FIG. 7B  is an enlarged schematic diagram showing the cutter mat, the fitting groove and a guide portion;  
         [0028]      FIG. 8  is an enlarged view of a circular region B in  FIG. 2 ;  
         [0029]      FIGS. 9A, 9B  and  9 C are an enlarged view of a circular region C in  FIG. 3 , an exploded view of a positioning member in a first embodiment and a side view of a protrusion member with a protrusion respectively;  
         [0030]      FIGS. 10A and 10B  are structural views of the positioning member in a second embodiment showing engaging and non-engaging states respectively, and  FIG. 10C  is a cross sectional view in  FIG. 10A ;  
         [0031]      FIGS. 11A and 11B  are structural views of the positioning member in a third embodiment showing engaging and non-engaging states respectively;  
         [0032]      FIGS. 12A and 12B  are structural views of the positioning member in a forth embodiment showing engaging and non-engaging states respectively;  
         [0033]      FIGS. 13A and 13B  are structural views of the positioning member in a fifth embodiment showing engaging and non-engaging states respectively;  
         [0034]      FIGS. 14A and 14B  are structural views of the positioning member in a sixth embodiment showing non-fixed and fixed states respectively;  
         [0035]      FIGS. 15A, 15B  and  15 C are structural views of the positioning member in a seventh embodiment.  FIG. 15A  shows a fixed state,  FIG. 15B  is a cross sectional view taken along line Y-Y of  FIG. 15A , and  FIG. 15C  is a cross sectional view showing a non-fixed state;  
         [0036]      FIG. 16A and 16B  are structural views of the positioning member in an eighth embodiment showing engaging and non-engaging states respectively; and  
         [0037]      FIG. 17A and 17B  are structural views of the positioning member in a ninth embodiment showing engaging and non-engaging states respectively. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0038]     Preferred embodiments of the present invention will hereinafter be described with reference to the drawings. A sheet cutter  1  basically comprises a base  2 , a guide rail  30 , a slider  40 , a cutter mat  50  and a paper-holding ruler  60 . First, the base  2 , as shown in  FIGS. 1 and 2 , forms in approximately square and is made of proper materials such as synthetic resin, and the top surface thereof has an installation table  3  on which sheet material such as paper is placed. The guide rail  30  is removably provided at and along either long side of the base  2  as shown in  FIG. 1  while a fitting groove  4  (see  FIG. 7 ) fitting the cutter mat  50  is provided along the guide rail  30 . On the installation table  3  of the base  2 , a pair of guide grooves  8 ,  8  is formed orthogonal to the guide rail  30 . In the guide grooves  8 ,  8 , a pair of foot portions  61 ,  61 , which is integrally formed with the paper-holding ruler  60 , is provided sidably along the guide grooves  8 ,  8 . It may be further provided with a handle  27  at either short side of the base  2 .  
         [0039]     The present invention is not limited thereto above, but the handle  27  may be provided at both short sides of the base  2 , or indication portions such as for ads may be instead provided at at least one of the short sides of the base  2 . Or, a dispenser or like may be provided in lieu of the indication portions for storing replaceable cutters.  
         [0040]     Next, details of the guide rail and the slider are hereinbelow explained. As shown in  FIGS. 1 and 5 , the guide rail  30  has longitudinally-continued chamfers  34  on both upper sides and is removably provided along either long side of the base  2  with an elastic member such as a coil spring (not shown). The top face of the guide rail  30  has a longitudinally-continued concave groove  31 , and both bottom ends of the guide rail  30  have longitudinally-continued and undercut engaged portions  33 ,  33  including top portions  33 A,  33 A and side portions  33 B,  33 B. The engaged portions may have another configurations such as concave grooves.  
         [0041]     The slider  40  has an interior surface analogous to but slightly larger than the exterior surface of the guide rail  30 . The slider  40  accordingly slides on the guide rail  30  with a certain clearance in a high linearity. The inner surface of the slider  40  has a convex slide protrusion  41  corresponding to the place where the concave groove  31  is formed. And, both bottom inner sides of the slider  40  have engaging projections  43 ,  43  comprising top engaging projections  43 A,  43 A and side engaging projections  43 B,  43 B so as to fit to the engaged portions  33 ,  33  of the guide rail  30 . In case the engaged portions  33 ,  33  are made by concave grooves, the engaging projections  43 ,  43  may be protrusions corresponding to the concave grooves.  
         [0042]     When the slider  40  is placed on the guide rail  30 , the slide protrusion  41  comes into contact with the concave groove  31 . However, as said above, because the interior surface of the slider  40  is analogous to but slightly larger than the exterior surface of the guide rail  30 , a certain clearance is formed between side concave grooves  31 A,  31 A of the concave groove  31  and side slide protrusions  41 A,  41 A of the convex slide protrusion  41 . That is, there does not have any surface contact between the side concave grooves  31 A,  31 A and the side slide protrusions  41 A,  41 A except between a bottom concave groove  31 B and a bottom slide protrusion  41 B. This makes the slider  40  moved in a high linearity. In this embodiment, the engaging projections  43 ,  43  and the engaged portions  33 ,  33  are also made non-contact from each other by having a certain clearances therebetween. That is, clearances are respectively given between the top engaging projections  43 A,  43 A and the top engaged portions  33 A,  33 A and further between the side engaging projections  43 B,  43 B and the side engaged portions  33 B,  33 B.  
         [0043]     When sliding the slider  40  along the guide rail  30 , the side slide protrusions  41 A,  41 A and the side concave grooves  31 A,  31 A may happen to have partial contacts with each other, but even in the case the engaging projections  43 ,  43  and the engaged portions  33 ,  33  still keep non-contact from each other. Since the slide protrusion  41  is thus guided along the concave groove  31  in a high linearity, it makes possible to minimize abrasion occurred between the slider and the guide rail. By making the length of both the side slide protrusions  41 A,  41 A and the side concave grooves  31 A,  31 A longer, it is further possible to improve a rate of the linearity.  
         [0044]     In case the sheet cutter is kept or carried with the handle  27  in inclined conditions, either the top engaging projections  43 A,  43 A or the side engaging projections  43 B,  43 B, or both may respectively abut against the top engaged portions  33 A,  33 A or the side engaged portions  33 B,  33 B, or both. The slider  40  can be thus prevented from slipping off from the guide rail  30 .  
         [0045]     As shown in  FIGS. 4 and 5 , the guide rail  30  further has a press member  35  along therewith pressing the sheet material in cutting processes, and there is also provided a certain clearance between the press member  35  and the installation table  3  for the sheet material interposed thereinto. In a non-working condition, the guide rail  30  is made energized upward to form the clearance. In a working condition, on the other hand, the slider  40  provided with a cutter  45  (such as a rotary cutter blade) in a cutter holder  44  is first moved aside to one end of the guide rail  30  for interposing the sheet material into the clearance. The slider  40  is then pressed downward to correspondingly press the guide rail  30 . While having the sheet material been pressed with the press member  35 , the slider  40  with the cutter  45  slides along the guide rail so as to cut the sheet material into optional dimensions.  
         [0046]     In another embodiment, as shown in  FIG. 6 , the top face of a guide rail  30 A may have a convex protrusion  32  while the interior of a slider  40 A may have a concave slide portion  42  corresponding to the place where the convex protrusion  32  is provided. The convex protrusion  32  is thus fitted to the concave slide portion  42 . When the convex protrusion  32  is fitted to the concave slide portion  42 , a top convex protrusion  32 B and a bottom concave slide portion  42 B are made contact; however, side convex protrusions  32 A,  32 A and side concave slide portions  42 A,  42 A facing each other remain non-contact. Between the side convex protrusions  32 A,  32 A and the side concave slide portions  42 A,  42 A, a certain clearance is formed so that the slider  40 A can be slided on the guide rail  30 A in a high linearity. And also, the engaging projections  43 ,  43  interiorly formed at both bottom ends of the slider  40 A and the engaged portions  33 ,  33  formed at both bottom portions of the guide rail  30 A are made non-contact due to a given clearance. This means that between the top engaging projections  43 A,  43 A and the top engaged portions  33 A,  33 A, and also between the side engaging projections  43 B,  43 B and the side engaged portions  33 B,  33 B, the given clearance is provided respectively.  
         [0047]     A cutter mat is next explained. As shown in  FIGS. 1 and 2 , at one end of the fitting groove  4 , an end fastener  6  is integrally provided with the base  2  so as to fasten one end portion  51  of the cutter mat  50 . At the other end of the fitting groove  4 , a rotary end-holder  7  is pivotally provided to the base  2  (vertically rotatable) so as to retain other end portion  52  of the cutter mat  50 . Here, the cutter mat  50  may be any configurations as long as fitted to the fitting groove  4 .  
         [0048]     The end fastener  6  has an approximately inverted L-shape in section. The interior side face thereof abuts on the one end portion  51  of the cutter mat  50  controlling the position in which the cutter mat  50  is installed. On the other hand, the interior upper face thereof presses the one end portion  51  by covering one end of the fitting groove  4 , so that the one end portion  51  is retained in the fitting groove  4 .  
         [0049]     The rotary end-holder  7  as the end fastener  6  has approximately inverted L-shape in section. The fitting groove  4  of one end side can be opened as shown in  FIG. 7A  (in a non-retaining state), so that the cutter mat  50  can be installed thereinto. After the cutter mat  50  is guided with a guide portion  5  toward the fitting groove  4 , the rotary end-holder  7  now in the non-retaining position ( FIG. 7A ) is rotated upward having the inner face thereof abutted against the other end portion  52  of the cutter mat  50 . The rotary end-holder  7  is rotated until reaching to a stopped position where the other end portion  52  is further pressed. Through the above, the cutter mat  50  is securely fixed to the fitting groove  4 .  
         [0050]     When the cutter mat  50  is retained in the fitting groove  4 , the end portions  51 ,  52  of the cutter mat  50  are both constrained with the end fastener  6  as well as the rotary end-holder  7 , both from upper and bilateral sides. Regardless of whether the sheet cutter  1  is kept aslant or carried with the handle  27 , the cutter mat  50  can firmly stay with the fitting groove  4 . When removing the cutter mat  50  from the fitting groove  4 , the rotary end-holder  7  is rotated downward from its retaining position so as to free the one end of the fitting groove  4 . Since the other end portion  52  of the cutter mat  50  has been uncovered, a user can remove the cutter mat  50  simply by hand.  
         [0051]     Next, a guide portion will be explained. As shown in  FIGS. 1, 2 ,  4  and  7 , a pair of the guide portions  5 ,  5 , which guides the cutter mat  50  to the fitting groove  4 , is provided integrally with the base  2 . The guide portions  5 ,  5  are placed at both proximal ends of the fitting groove  4 , but the interval therebetween is made shorter than the length of the cutter mat  50 . The guide portions  5 ,  5  include inclined portions  5 A,  5 A made inclined to the fitting groove  4 . See  FIG. 7B . The inclined angle thereof can be optional, but it may be determined in consideration of that the cutter mat  50  is slided by its own weight into the fitting groove  4  when placed on the inclined portions  5 A,  5 A.  
         [0052]     The configuration of the guide portions is not limited to the aforementioned. It may however have three or more guide portions, or the inclined portions may be any optional value as long as the cutter mat is smoothly guided by hand or any other tools into the fitting groove.  
         [0053]     A paper-holding ruler and a guide groove are explained hereinbelow referring to  FIGS. 1 and 2 . A pair of positioning steps  11 ,  11  positioning the sheet material is provided at both short sides of the base  2  and orthogonal to the guide rail  30 . On the installation table  3  of the base  2  further has a pair of the guide grooves  8 ,  8 , orthogonal to the guide rail  30 , in which the foot portions  61 ,  61  of the paper-holding ruler  60  are sidably guided. These guide grooves  8 ,  8  have a concave form approximately trapezoid in section, and the foot portions  61 ,  61  have a convex form in section to be fitted and held at the guide grooves  8 ,  8 . The sectional configuration of the guide grooves  8 ,  8  may be any inverted T-shapes as long as it has a closing bottom wider than an opening top.  
         [0054]     The section of the foot portions  61 ,  61  of the paper-holding ruler  60  is correspondingly formed to the one of the guide grooves  8 ,  8  having the inverted T-shape. Even though the sheet cutter  1  is placed slantwise, the foot portions  61 ,  61  well fixed to the guide grooves  8 ,  8  are not accordingly pull out from the guide grooves. Although described later, by introducing projections  25 ,  25  into concavities  62 ,  62  on the foot portions  61 ,  61 , the foot portions  61 ,  61  are more stably fixed to the guide grooves  8 ,  8 .  
         [0055]     The paper-holding ruler  60  with a pair of the foot portions  61 ,  61  integrally and orthogonally provided therewith has a side positioning the sheet material while concurrently retaining levers  63 ,  63  at both top end sides. When the paper-holding ruler  60  is placed on the installation table  3 , the levers  63 ,  63  may function with engaging members (not shown) so as to engage with the guide grooves  8 ,  8 . The paper-holding ruler  60  is thus positioned and fixed at a given place.  
         [0056]     Next, a positioning means  12  of a first embodiment is hereinafter explained referring to  FIGS. 2, 3  and  8 . The installation table  3  of the base  2  has hollows  9 , which are orthogonal to the guide grooves  8 ,  8 . The projections  25 ,  25  integrally formed with projection members  24 ,  24  (hereinafter explained in detail) are sidably fitted to the hollows  9 . In case the paper-holding ruler  60  is placed and fixed out of the installation table  3 , the projections  25 ,  25  are engaged with concavities  62 ,  62  of the foot portions  61 ,  61 . A back surface of the base  2  has a pair of bottom face grooves  10 ,  10  in position where corresponding to the guide grooves  8 ,  8 . By fixing the foot portions  61 ,  61  of the paper-holding ruler  60  in the bottom face grooves  10 ,  10 , the paper-holding ruler  60  can be positioned and fixed at a given place.  
         [0057]     The positioning means  12 , as shown in  FIG. 9 , comprises: the pair of projection members  24 ,  24  arranged in a pair of projection guiding-portions  13 ,  13  formed orthogonally to a pair of the bottom face grooves  10 ,  10 ; springs  23 ,  23  energizing the projection members  24 ,  24  to the bottom face grooves  10 ,  10 ; a projection operation member  17  keeping the projections  25 ,  25  engaged with the concavities  62 ,  62  of the foot portions  61 ,  61 ; and a pair of intermediate operation members  21 ,  21  placed between the projection operation member  17  and the springs  23 ,  23 .  
         [0058]     Referring to  FIG. 9 , the pair of projection guiding-portions  13 ,  13  and intermediate operation guides  14 ,  14  are integrally provided at the backside of the base  2  and also placed between the pair of bottom face grooves  10 ,  10 . At the connection between the projection guiding-portions  13 ,  13  and bottom face grooves  10 ,  10 , the hollows  9 ,  9  (see  FIG. 8 ) are formed running through the top face of the projection guiding-portions  13 ,  13  and the installation table  3 . Between the bottom face grooves  10 ,  10 , a retaining portion  15  movably holding the projection operation member  17  is integrally provided on the back face of the base  2 . Here, the retaining portion  15  is provided having a step that the projection operation member  17  can be placed between the retaining portion  15  and the installation table  3 . See  FIG. 4 .  
         [0059]     The projection operation member  17  as shown in  FIGS. 3 and 9  has a pair of pressing portions  19 ,  19  with inclination of approximately 45 degrees to a direction that the projection operation member  17  is moved. The retaining portion  15  has a threaded hole (not shown) that a screw  20  is mounted. The surface of the projection operation member  17  has an operation surface  18  (see  FIGS. 2 and 4 ), and the projection operation member  17  is installed into the retaining portion  15  making the operation surface  18  approximately being on a level with the installation table  3 . Through the mounting screw  20 , the projection operation member  17  can be movably retained along a guiding long-hole  16  formed on the retaining portion  15 . The projection members  24 ,  24  are further integrally provided with the projections  25 ,  25  at one end thereof and have spring holders  26 ,  26  inside thereof. Here, one ends of the intermediate operation members  21 ,  21  are made contact with the springs  23 ,  23 , whereas the other ends thereof have pressed surfaces  22 ,  22  with inclination of 45 degrees.  
         [0060]     The positioning means  12  of the first embodiment is installed in the base  2  in the following steps. The projection operation member  17  is first fitted into the retaining portion  15  provided on the back of the base  2  in such a manner that the pressing portions  19 ,  19  are faced toward the guide rail  30 . The mounting screw  20  is introduced into the guiding long-hole  16  and then installed in the threaded hole of the projection operation member  17 . The projection members  24 ,  24  are placed inside of the projection guiding-portions  13 ,  13  so as to have the projections  25 ,  25  fitted into the hollows  9 ,  9 . The intermediate operation members  21 ,  21  are then introduced into the intermediate operation guides  14 ,  14 . The springs  23 ,  23  are next compressed and installed into the spring holders  26 ,  26  of the projection members  24 ,  24  and the intermediate operation guides  14 ,  14 . The pressing portions  19 ,  19  of the projection operation member  17  are abutted in this condition to the pressed surfaces  22 ,  22  of the intermediate operation members  21 ,  21 . While heading toward the guide grooves  8 ,  8 , the projections  25 ,  25  are engaged with the concavities  62 ,  62  formed on the foot portions  61 ,  61  of the paper-holding ruler  60 . After the positioning means  12  is installed on the back of the base  2 , the positioning means  12  may optionally be covered to avoid external exposure.  
         [0061]     In the first embodiment, when the paper-holding ruler  60  needs to be fixed, the projection operation member  17  is first moved toward the side of the guide rail  30  to give more energy toward the springs  23 ,  23 . The projections  25 ,  25  projected toward the guide grooves  8 ,  8  with the springs  23 ,  23  are engaged with the concavities  62 ,  62  formed on the foot portions  61 ,  61  to be fixed. On the other hand, when changing the position of the paper-holding ruler  60 , the projection operation member  17  is simply moved away from the guide rail  30  lessening the energy toward the springs  23 ,  23 . The foot portions  61 ,  61  become movable along the guide grooves  8 ,  8 . Based on the structure above, time taken for cutting the sheet materials can be notably shortened.  
         [0062]     Next, the positioning means of another embodiments are still explained hereinafter, mainly focusing on structures of foot portions and projections. In the second embodiment of the positioning means, as shown in  FIG. 10 , one end portions of plate springs  70 ,  70  are fastened with screws  73 ,  73  to sides  10 A,  10 A of the bottom face grooves  10 ,  10  formed on the back of the installation table  3 . The plate springs  70 ,  70  have curvatures  71 ,  71  curved toward the guide grooves  8 ,  8 . The curvatures  71 ,  71  project toward the guide grooves  8 ,  8  through openings  10 B,  10 B to engage with concavities  62 ,  62  on the foot portions  61 ,  61 . The other ends of the plate springs  70 ,  70 , plate spring end portions  72 ,  72 , are movably retained to stowing portions  74 ,  74  formed on the sides  10 A,  10 A of the bottom face grooves  10 ,  10 .  
         [0063]     For positioning and fixing the paper-holding ruler  60  in the second embodiment, the steps needed to be taken are: 1] transferring the foot portions  61 ,  61  along the guide grooves  8 ,  8  from the state where the curvatures  71 ,  71  are placed out of the concavities  62 ,  62  as shown in  FIG. 10B  to the state where the curvatures  71 ,  71  are placed facing with the concavities  62 ,  62  as shown in  FIGS. 10A and 10C ; 2) having the curvatures  71 ,  71  being projected toward the concavities  62 ,  62  with elastic force; and 3) having the curvatures  71 ,  71  engaged with the concavities  62 ,  62 . According to the second embodiment explained above, because the projections are replaced by the curvatures of the plate springs, it succeeds to fabricate the positioning means with lesser pieces compared with the first embodiment. Time needed for cutting the sheet materials is further shortened.  
         [0064]     In the third embodiment of the positioning means, as shown in  FIG. 11 , one ends of plate springs  70 A,  70 A are fastened with a screw  73 A on the back of foot portions  61 A,  61 A, for example, on sides  64 A,  64 A of the foot portions  61 A,  61 A. The plate springs  70 A,  70 A have curvatures  71 A,  71 A curved toward the installation table  3 . The curvatures  71 A,  71 A project toward openings  64 B,  64 B so as to engage concavities  62 A,  62 A on the installation table  3 . The other ends of the plate springs  70 A,  70 A, plate spring end portions  72 A,  72 A, are movably retained to stowing portions  74 A,  74 A formed on the sides  64 A,  64 A of the foot portions  61 A,  61 A.  
         [0065]     For positioning and fixing the paper-holding ruler  60  in the third embodiment, the steps needed to be taken are: 1) transferring the foot portions  61 A,  61 A along the guide grooves  8 ,  8  from the state where the curvatures  71 A,  71 A are placed out of the concavities  62 A,  62 A as shown in  FIG. 11B  to the state where the curvatures  71 A,  71 A are placed facing with the concavities  62 A,  62 A as shown in  FIG. 11A ; 2) having the curvatures  71 A,  71 A being projected toward the concavities  62 A,  62 A with elastic force; and 3) having the curvatures  71 A,  71 A engaged with the concavities  62 A,  62 A. According to the third embodiment explained above, the same effect with the second embodiment can be attained.  
         [0066]     In the fourth embodiment of the positioning means, as shown in  FIG. 12 , cut-out portions  75 ,  75  are provided by cutting out the back of the installation table  3 , specifically, the installation table  3  proximal to the bottom face grooves  10 ,  10 . The cut-out portions  75 ,  75  where facing toward the guide grooves  8 ,  8  have swellings  25 A,  25 A at the center thereof and deflection areas  76 ,  76  integrally formed therewith at both sides of the swellings  25 A,  25 A. The swellings  25 A,  25 A are thus engaged with concavities  62 ,  62  formed on the foot portions  61 ,  61 .  
         [0067]     For positioning and fixing the paper-holding ruler  60  in the fourth embodiment, the steps needed to be taken are: 1) transferring the foot portions  61 ,  61  along the guide grooves  8 ,  8  from the state where the swellings  25 A,  25 A are placed out of the concavities  62 ,  62  as shown in  FIG. 12B  to the state where the swellings  25 A,  25 A are placed facing with the concavities  62 ,  62  as shown in  FIG. 12A ; 2) having the swellings  25 A,  25 A being projected toward the concavities  62 ,  62  with elastic force of the deflection areas  76 ,  76 ; and 3) having the swellings  25 A,  25 A engaged with the concavities  62 ,  62 . According to the forth embodiment explained above, further reduction of the parts can be attained compared to the second and third embodiments.  
         [0068]     In the fifth embodiment of the positioning means, as shown in  FIG. 13 , cut-out portions  75 A,  75 A are provided by cutting out the foot portions  61 B,  61 B. The surfaces of the cut-out portions  75 A,  75 A facing toward the installation table  3  have swellings  25 B,  25 B at the center thereof and deflection areas  76 A,  76 A integrally formed therewith at both sides of the swellings  25 B,  25 B. The swellings  25 B,  25 B are thus engaged with concavities  62 A,  62 A formed on the installation table  3 .  
         [0069]     For positioning and fixing the paper-holding ruler  60  in the fifth embodiment, the steps needed to be taken are: 1) transferring the foot portions  61 B,  61 B along the guide grooves  8 ,  8  from the state where the swellings  25 B,  25 B are placed out of the concavities  62 A,  62 A as shown in  FIG. 13B  to the state where the swellings  25 B,  25 B are placed facing with the concavities  62 A,  62 A as shown in  FIG. 13A ; 2) having the swellings  25 B,  25 B being projected toward the concavities  62 A,  62 A with elastic force of the deflection areas  76 A,  76 A; and 3) having the swellings  25 B,  25 B engaged with the concavities  62 A,  62 A. According to the fifth embodiment explained above, the same effect with the fourth embodiment can be attained.  
         [0070]     In the sixth embodiment of the positioning means, as shown in  FIG. 14 , on the back of the installation table  3 , a first hole  82  and second holes  83 ,  83  are provided approximately orthogonal to each other. The first hole  82  is made in the same direction that the foot portion  61  is moved while the second holes  83 ,  83  are made intersecting with the guide grooves  8 ,  8 . At the first hole  82 , a first link  77  and a second link  78  are movably fitted on a pivotable connection  80 . At the second holes  83 ,  83 , axial parts  81 ,  81  provided on each end  79 ,  79  of the first link  77  and the second link  78  are movably fitted. Each of the ends  79 ,  79 , as shown in  FIG. 14B , is projected into the guide grooves  8 ,  8  so as to engage with the concavities  62 ,  62  of the foot portions  61 ,  61 . The pivotable connection  80  further has an operation member (not shown in figures) operating the first link  77  and the second link  78 .  
         [0071]     For positioning and fixing the paper-holding ruler  60  in the sixth embodiment, the steps needed to be taken are: 1) transferring the foot portions  61 ,  61  along the guide grooves  8 ,  8  from the state where each of the ends  79 ,  79  of the first link  77  and the second link  78  is placed out of the concavities  62 ,  62  of the foot portions  61 ,  61  as shown in  FIG. 14A  to the state where each of the ends  79 ,  79  is placed facing with the concavities  62 ,  62  as shown in  FIG. 14B ; 2) moving the operation member attached to the one end of the pivotable connection  80  along the second hole  82 ; 3) having each of the ends  79 ,  79  being projected toward the sides of the guide grooves  8 ,  8 ; and 4) having the ends  79 ,  79  engaged with the concavities  62 ,  62 . According to the sixth embodiment explained above, because no member such as projections or swellings, which is needed to be energized by elastic force, is provided unlike the aforementioned other embodiments, it enables to have the foot portions of the paper-holding means more firmly fixed thus giving more stable cutting operations.  
         [0072]     In the seventh embodiment of the positioning means, as shown in  FIG. 15 , on the back of the installation table  3 , a first hole  82 A is provided perpendicular to the installation table  3  while a second holes  83 A,  83 A are provided parallel to the installation table  3 . The second holes  83 A,  83 A are then formed in the intersectional direction to which the foot portion  61  is moved. The first hole  82 A is provided at the appropriate area on the back of the installation table  3 . At the first long-hole  82 A, a first link  77 A and a second link  78 A are movably fitted on a pivotable connection  80 A. At the second holes  83 A,  83 A, axial parts  81 A,  81 A provided on each end  79 A,  79 A of the first link  77 A and the second link  78 A are movably fitted. Each of the ends  79 A,  79 A, as shown in  FIG. 15A , is projected into the guide grooves  8 ,  8  so as to engage with the concavities  62 ,  62  of the foot portions  61 ,  61 . The pivotable connection  80 A further has an operation member  84  operating the first link  77 A and the second link  78 A.  
         [0073]     For positioning and fixing the paper-holding ruler  60  in the seventh embodiment, the steps needed to be taken are: 1) transferring the foot portions  61 ,  61  along the guide grooves  8 ,  8  from the state where each of the ends  79 A,  79 A of the first link  77 A and the second link  78 A is placed out of the concavities  62 ,  62  of the foot portions  61 ,  61  as shown in  FIG. 15C  to the state where each of the ends  79 A,  79 A is placed facing with the concavities  62 ,  62  as shown in  FIG. 15B ; 2) having the pivotal connection  80 A moved along the second hole  82 A with the operation member  84 ; 3) having each of the ends  79 A,  79 A being projected toward the sides of the guide grooves  8 ,  8 ; and 4) having the ends  79 A,  79 A engaged with the concavities  62 ,  62 . According to the seventh embodiment explained above, the same effect with the sixth embodiment can be attained.  
         [0074]     In the eighth embodiment of the positioning means, as shown in  FIG. 16 , on the back of foot portions  61 C,  61 C such as sides  64 A,  64 A, one ends of plate springs  70 B,  70 B are fastened through screws  73 B,  73 B. The other ends thereof have projections  25 C,  25 C projected toward the side of the installation table  3 . The projections  25 C,  25 C are projected from guiding member  85 ,  85  integrally formed on the sides  64 A,  64 a of the foot portions  61 C,  61 C so as to engage with concavities  62 A,  62 A formed on the installation table  3 .  
         [0075]     For positioning and fixing the paper-holding ruler  60  in the eighth embodiment, the steps needed to be taken are: 1) transferring the foot portions  61 C,  61 C along the guide grooves  8 ,  8  from the state where the projections  25 C,  25 C are placed out of the concavities  62 A,  62 A as shown in  FIG. 16B  to the state where the projections  25 C,  25 C are placed facing with the concavities  62 A,  62 A as shown in  FIG. 16A ; 2) having the projections  25 C,  25 C being projected toward the concavities  62 A,  62 A with elastic force of the plate springs  70 B,  70 B; and 3) having the projections  25 C,  25 C engaged with the concavities  62 A,  62 A. According to the eighth embodiment explained above, time needed for the cutting operation can be shortened as same as another embodiments.  
         [0076]     In the ninth embodiment of the positioning means, as shown in  FIG. 17 , guiding members  85 A,  85 A integrally formed on the back of foot portions  61 D,  61 D are extended from sides  64 A,  64 A facing the installation table  3  to the other sides  64 C,  64 C. The guiding members  85 A,  85 A hold coil springs  86 ,  86  and projections  25 D,  25 D therein, so that the projections  25 D,  25 D are energized toward the side of the installation table  3  with the coil springs  86 ,  86 . The projections  25 D,  25 D are thus made projected from the guiding members  85 A,  85 A so as to engage with concavities  62 A,  62 A formed on the installation table  3 .  
         [0077]     For positioning and fixing the paper-holding ruler  60  in the ninth embodiment, the steps needed to be taken are: 1) transferring the foot portions  61 D,  61 D along the guide grooves  8 ,  8  from the state where the projections  25 D,  25 D are placed out of the concavities  62 A,  62 A formed on the installation table  3  as shown in  FIG. 17B  to the state where the projections  25 D,  25 D are placed facing with the concavities  62 A,  62 A as shown in  FIG. 17A ; 2) having the projections  25 D,  25 D being projected toward the concavities  62 A,  62 A with elastic force of the coil springs  86 ,  86 ; and 3) having the projections  25 D,  25 D engaged with the concavities  62 A,  62 A. According to the ninth embodiment explained above, the same effect with the eighth embodiment can be achieved.  
         [0078]     Although the plate springs  70 B,  70 B and the coil springs  86 ,  86  are explained in the eighth and ninth embodiments respectively, these energized means are not limited thereto but may be any materials or constitutions as long as they have elastic characteristics.