WO2001078952A1

WO2001078952A1 - Rotating knife for cutting paper etc

Info

Publication number: WO2001078952A1
Application number: PCT/KR2001/000637
Authority: WO
Inventors: Gil-Ho Jung
Original assignee: Jung Gil Ho
Priority date: 2000-04-18
Filing date: 2001-04-17
Publication date: 2001-10-25
Also published as: KR100370971B1; KR20010000633A; AU5272401A

Abstract

The present invention relates to a rotating knife for cutting paper etc. which is configured such that a user can conveniently use it by selectively fixing or rotating a blade of the knife in accordance with a required shape to be cut upon cutting of the paper etc. To this end, the present invention provides a rotating knife for cutting the paper etc. comprising a body; a rotating shaft rotatably installed within the body; a blade which is detachably coupled with the rotating shaft and exposed to the exterior in front of the body, and has a leading end disposed at an eccentric position spaced apart at a predermined distance from a center of rotation; and a means for supporting the rotating shaft so than the rotating shaft can be smoothly rotated within the body.

Description

ROTATING KNIFE FOR CUTTING PAPER ETC.

FIELD OF THE INVENTION The present invention relates to a rotating knife for cutting paper etc., and more particularly, to a rotating knife for cutting paper etc., wherein a user can conveniently utilize it by selectively rotating or fixing a blade of the knife in consideration of a cutting form when cutting the paper etc.

BACKGROUND OF THE INVENTION Generally, a knife for cutting paper etc. is a stationery knife which is used for cutting the paper etc. by changing the length of its blade according to the thickness of the paper etc. to be cut. In addition to the cutting of the paper etc., the stationery knife is commonly used for various uses.

Such conventional knife for cutting the paper etc. will be described with reference to FIG. 1.

The conventional knife for cutting the paper etc. includes a holding portion 4000 serving as a grip, a blade 1000 for cutting the paper etc. placed within the holding portion 4000 and formed with a coupling aperture 2000 at one end thereof, and an adjustor 3000 coupled with the coupling aperture 2000 of the blade 1000 for controlling the length of the blade 1000.

At this time, a cut-away portion at the center of the holding portion 4000 is formed with convex and concave portions 5000 for controlling the length of the blade 1000 upon operation of the adjustor 3000. A rear portion of the holding portion 4000 is provided with a breakaway preventer 6000 which performs a function of preventing the adjustor 3000 from coming out when assembled thereinto and simultaneously allows the blade 1000 to be replaced when demounted from the holding portion 4000.

However, as for the conventional knife for cutting the paper etc. constructed as such, there are limitations and problems in use in view of its structural characteristics, as follows.

That is, the conventional knife for cutting the paper etc. did not generally give rise to a problem when cutting the paper etc. in a straight line. However, when the knife is used for cutting the paper etc. in a curved line, a circle or the like, a user should cut the paper while continuously turning the paper or the Icnife in accordance with cutting directions.

On the other hand, if the cutting operation is performed in this way, but goes wrong contrary to user's wishes, there was a disadvantage in that an additional auxiliary means such as a curve ruler must be used. Therefore, in a case where the paper etc. are cut in a curved or circular line by using the conventional knife for cutting the paper etc., there are problems in that efficiency of the cutting operation is lowered, and at the same time, the user is subject to repeated trial and error and the material of paper etc. is wasted since the paper etc. are not easily cut in a desired form. On the other hand, since the conventional Icnife for cutting the paper etc. takes the shape of a thin plate as a whole, it is difficult to grip the knife, and thus, the efficiency of the cutting operation is further lowered. Therefore, there is a structural problem with the conventional Icnife. SUMMARY OF THE INVENTION The present invention is contemplated to solve the above problems in the conventional knife for cutting paper etc. as mentioned above. An object of the present invention is to provide a Icnife for cutting paper etc., wherein its structure is improved in such a manner that a blade of the Icnife can be selectively fixed or rotated, so that the paper etc. can be cut in a straight line, and at the same time, can be easily cut in a desired form by means of rotation of the blade when a user simply and smoothly moves the knife in a direction of cutting the paper etc. in the same way that the user draws a line with a pencil upon cutting the paper etc. in the curved line. According to the present invention for achieving the object, there is provided a rotating knife for cutting paper etc. comprising a body; a rotating shaft rotatably installed within the body; a blade which is detachably coupled with the rotating shaft and exposed to the exterior in front of the body, and has a leading end disposed at an eccentric position spaced apart at a predetermined distance from a center of rotation; and a means for supporting the rotating shaft so that the rotating shaft can be smootlily rotated within the body.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of one example of a conventional knife for cutting paper etc.

FIG. 2 is a longitudinal sectional view of a rotating knife for cutting paper etc. according to a first embodiment of the present invention. FIG. 3 is an exploded perspective view of FIG. 2.

FIG. 4 is a longitudinal sectional view showing a state where the rotating knife for cutting paper etc. according to the first embodiment of the present invention is used. FIG. 5 is a conceptual view taken along line I-I in FIG. 4 for illustrating changes in positions of a blade of the rotating knife while cutting the paper etc.

FIG. 6 is a longitudinal sectional view showing the interior constitution of the rotating nife for cutting paper etc. according to a second embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing the interior constitution of the rotating knife for cutting paper etc. according to a third embodiment of the present invention.

FIG. 8 is a sectional view taken along line II-II in Fig. 7. FIG. 9a is a perspective view showing a button for locking a rotating shaft in

FIGS. 7 and 8.

FIG. 9b is a perspective view showing a leaf spring in FIGS. 7 and 8.

FIG. 10 is a partially sectioned perspective view showing the interior constitution of a rotating knife for cutting paper etc. according to a fourth embodiment of the present invention.

FIG. 11 is a longitudinal sectional view showing the interior constitution of a rotating Icnife for cutting paper etc. according to a fifth embodiment of the present invention.

FIGS. 12a and 12b are perspective views showing other examples of the blade employed in the rotating Icnife for cutting paper etc. of the present invention.

FIG. 13 is a longitudinal sectional view showing the interior constitution of a rotating knife for cutting paper etc. according to a sixth embodiment of the present invention.

FIG. 14 is a longitudinal sectional view showing the interior constitution of a rotating Icnife for cutting paper etc. according to a seventh embodiment of the present invention.

DETAILED DESCRIPTION FOR PREFERRED EMBODIMENT Hereinafter, preferred embodiments of the present invention will be explained in detail with reference to FIGS. 2 to 12b of the accompanying drawings.

First, a first embodiment of the present invention will be described with reference to FIGS. 2 to 5.

FIG. 2 is a longitudinal sectional view showing the constitution of a rotating lαiife for cutting paper etc. according to the first embodiment of the present invention, and FIG. 3 is an exploded perspective view of FIG. 2.

In addition, FIG. 4 is a longitudinal sectional view showing a state where the rotating Icnife for cutting paper etc. according to the first embodiment of the present invention is used, and FIG. 5 is a conceptual view taken along line I-I in FIG. 4 for illustrating changes in positions of a blade of the rotating Icnife while cutting the paper etc. The rotating Icnife 1 according to the first embodiment of the present invention includes a body 4 serving as a grip; a rotating shaft 31 rotatably installed within the body 4; a blade 2 which is detachably coupled with the rotating shaft 31 and exposed to the exterior in front of the body 4, and has a leading end disposed at an eccentric position at a predetermined distance from a center of rotation; and a means for supporting the rotating shaft so that the rotating shaft 31 can be smoothly rotated within the body 4.

At this time, a bearing 32 as the means for supporting the rotating shaft is installed between an inner periphery of the body and an outer periphery of the rotating shaft.

Further, the rotating knife 1 of the present invention is further provided with a means for locking the rotating shaft so that a user can selectively restrain the rotation of the rotating shaft.

At this time, the means for locking the rotating shaft includes a fixing member 35 for preventing the rotation which is installed movably along a longitudinal direction within the body 4 and has a polygonal through-hole formed at the center thereof; and a tapered portion 34 which is formed at a distal end of the rotating shaft 31 so that the rotating shaft 31 is constrained in the fixing member 35 when the tapered portion 34 is fitted into the polygonal through-hole of the fixing member 35.

At this time, a rear portion of the body is formed with a rectangular guiding groove 41 having a predetermined length along the longitudinal direction of the body. A rear end of the rectangular guiding groove 41 is formed with a fixing groove 45 extending in a direction perpendicular to the longitudinal direction of the body 4. One side of an outer periphery of the fixing member 35 is further provided with an operating knob 351 which protrudes through and moves along the rectangular guiding groove 41 formed in the body 4 in the longitudinal direction thereof. Thus, when the operating knob 351 is positioned at a front portion of the rectangular guiding groove 41, the rotation of the rotating shaft is prevented and the blade 2 is constrained. When the operating knob 351 is positioned in the fixing groove 45, the blade 2 can freely rotate.

On the other hand, according to the present invention, a safety cover 7 is additionally provided so that the blade 2 is prevented from being exposed to the exterior when coupled with a front portion of the body 4. Thus, the user is not injured by the blade 2 when carrying the rotating Icnife.

The rotating Icnife according to the first embodiment of the present invention constructed as such operates as follows.

First, if the user intends to cut the paper etc. in a curved line, the operating knob 351 is retracted toward the rear end of the rectangular guiding groove 41 and then laid aside so that the operating Icnob 351 is positioned within the fixing groove 45 which is formed at the rear end of the guiding groove 41 and extends in the direction perpendicular to the longitudinal direction of the body 4, as shown in FIG. 4.

In this way, when the operating Icnob 351 is positioned within the fixing groove 45, the operating Icnob 351 is caught in inner walls of the fixing groove 45 and the fixing member 35 is kept sufficiently spaced apart from the tapered portion 34 formed in a rear portion of the rotating shaft 31. Thus, the rotating shaft 31 can be released from the constraint of the fixing member 35 so as to freely rotate.

In such state, if the user cuts the paper etc., for example, in a curved line, as shown in FIG. 5, the user holds the rotating Icnife 1 in the same manner as a ballpoint pen or a pencil, brings a leading end of the blade 2 of the rotating knife 1 into close contact with a surface of the paper etc., and moves the rotating knife 1 along the cutting direction while applying predetermined force to the rotating knife in a direction perpendicular to the surface of the paper etc. At this time, the paper etc. are cut while the blade 2 is smoothly rotated to conform to the cutting direction.

That is, according to the rotating knife 1 of the present invention, the leading end of the blade 2 is offset at a predetermined distance from the center of rotation of the rotating shaft 31 , and the rotating shaft 31 coupled with the blade 2 is supported by the bearing 32 within the body 4 so as to be smoothly rotatable. Therefore, when the center of rotation of the body 4 moves with the leading end of the blade 2 pressed against the surface of the paper etc., the blade 2 is subject to a rotational moment by which the blade tends to rotate about the leading end abutted on the surface of the paper etc. Due to the rotational moment, the blade 2 tends to position in such a manner that its orientation conforms to a direction in which the center of rotation of the body 4 moves. Accordingly, the orientation of the blade 2 of the rotating Icnife 1 always conforms to the direction in which the center of rotation of the body 4 moves.

Therefore, as shown in FIG. 5, when the body 4 of the rotating knife 1 moves along the cutting line so that the center of rotation of the body 4 conforms to a line to be cut on the paper etc., a edge 3 of the blade 2 continues to move along a locus on which the center of rotation of the body 4 moves with the edge 3 pressed against the surface of the paper etc. Consequently, the paper etc. are cut in a desired form.

On the other hand, if the user intends to cut the paper etc. in a straight line other than the curved line exemplified in FIG. 5, the user causes the operating knob 351 positioned within the fixing groove 45 to come off the fixing groove 45 and to be positioned at a front portion of the rectangular guiding groove 41.

In this way, when the fixing member 35 is fitted over the polygonal tapered portion 34 formed at the rear portion of the rotating shaft 31, the rotating shaft 31 is prevented from rotating due to interference between the through-hole of the fixing member 35 and the tapered portion 34. Consequently, since the rotation of the rotating shaft 31 is prevented due to the constraint of the fixing member 35 and the rotation of the blade 2 coupled with the rotating shaft is also prevented, the paper etc. can be conveniently cut in a straight line in the same manner that the paper etc. are cut by a conventional non-rotational Icnife for cutting paper etc. On the other hand, when the rotating Icnife of the present invention is not in use, the safety cover 7 is coupled with the front portion of the body 4 to prevent the blade 2 from being exposed to the exterior, so that accidents such as injury to the hands of the user by the edge 3 due to carelessness or the like can be prevented beforehand.

Hereinafter, a rotating Icnife for cutting paper etc. according to a second embodiment of the present invention will be described with reference to FIG. 6. In the same way as the above first embodiment, the rotating knife 1 according to the second embodiment of the present invention also includes the body 4; the rotating shaft 31 rotatably installed within the body 4; the blade 2 which is detachably coupled with the rotating shaft 31 and exposed to the exterior in front of the body 4, and has the leading end disposed at the eccentric position at the predetermined distance from the center of rotation; and the means for supporting the rotating shaft so that the rotating shaft 31 can be smoothly rotated within the body 4.

In addition, the second embodiment is identical to the first embodiment in that there are provided the fixing member 35 and the operating Icnob 351 so that the rotation and fixation of the rotating shaft 31 can be selectively made in accordance with the operation of the user; and in that there is provided the tapered portion 34 fitted into the through-hole of the fixing member 35 at the rear portion of the rotating shaft 31.

On the other hand, the means for supporting the rotating shaft of the rotating Icnife according to the second embodiment of the present invention consists of the rear distal end of the rotating shaft 31 and a concave or convex spherical support 6 provided at the rear portion of the body 4. The rear distal end of the rotating shaft 31 is in point contact with the support 6. The point contact reduces friction therebetween, so that the rotating shaft 31 can smoothly rotate.

Moreover, an annular catching ledge 311 is formed on an outer peripheral portion of an axially predetermined portion of the rotating shaft 31, and projections 44 are formed on an inner peripheral portion of the body 4 so that the catching ledge 311 of the rotating shaft 31 can be caught by the projections 44. Thus, when the Icnife 1 is stood vertically, the rotating shaft 31 is prevented from coming off the body 4.

Since the cutting operation of the rotating knife according to the second embodiment of the present invention constructed as such is identical to that of the rotating knife according to the first embodiment, the description thereof will be omitted.

On the other hand, contrary to the first and second embodiments, instead of the rectangular guiding groove 41 and the fixing groove 45 formed in the body 4, only the rectangular guiding groove 41 is formed and a boss of a predetermined length is formed on one side of the rear portion of the rectangular guiding groove 41 to protrude toward the center of the guiding groove. Thus, when the operating knob 351 of the fixing member 35 is snap-fitted over and behind the boss serving as a critical point, the fixing member 35 is prevented from interfering with the rotating shaft 31. When the operating Icnob 351 gets over the boss to be positioned at the front portion of the rectangular guiding groove 41, the tapered portion 34 at the rear portion of the rotating shaft 31 is constrained in the fixing member 35 so as to prevent the rotation of the rotating shaft 31.

Hereinafter, a rotating Icnife for cutting paper etc. according to a third embodiment of the present invention will be described with reference to FIGS. 7 to 9b.

FIG. 7 is a longitudinal sectional view showing the interior constitution of the rotating lαiife according to the third embodiment of the present invention, and FIG. 8 is a sectional view taken along line II- II in FIG. 7.

Additionally, FIG. 9a is a perspective view showing a button for locking a rotating shaft in FIGS. 7 and 8, and FIG. 9b is a perspective view showing a leaf spring in FIGS. 7 and 8. The rotating knife according to the third embodiment of the present invention is identical to that of the first and second embodiments in that it includes the body 4 serving as the grip; the rotating shaft 31 rotatably installed within the body 4; the blade 2 which is detachably coupled with the rotating shaft 31 and exposed to the exterior in front of the body 4, and has the leading end disposed at the eccentric position at the predetermined distance from the center of rotation; and the means for supporting the rotating shaft so that the rotating shaft 31 can be smoothly rotated within the body 4, except the constitution of a means for locking the rotating shaft.

That is, in this case, the means for locking the rotating shaft includes serrations 310 formed on an outer peripheral surface of the front portion of the rotating shaft 31 to be detachably coupled with the blade 2; a locking button 315 installed through the body 4 and formed with serrations 320 at an inner end thereof so as to be mated with the serrations 310 of the rotating shaft 31; and an annular leaf spring 33 installed within the body 4 and spaced apart at a distance radially and outwardly from the rotating shaft 31.

Both sides of the locking button 315 are formed with protruding press pieces 350 for pressing both ends of an opening in the annular leaf spring 33.

The rotating Icnife according to the third embodiment of the present invention constructed as such can cut the paper etc. in a straight or curved line, as follows.

First, when the paper etc. are required to be cut in a straight line, the rotating knife is used for cutting the paper etc. with the locking button 315 pressed so as to constrain the rotating shaft 31.

That is, when the user grips the rotating knife and presses the locking button 315 with a certain force, the locking button 315 moves into the body 4 against restoring force of the leaf spring 33.

At this time, the press pieces 350 formed on both the sides of the locking button 315 press outer surfaces of both the ends of the opening in the annular leaf spring 33.

As described above, when the locking button 315 moves into the body 4 against the restoring force of the leaf spring 33, the serrations 320 formed on the inner end of the locking button 315 are mated with the serrations 310 formed on the outer peripheral surface of the rotating shaft 31. Accordingly, when the rotating shaft 31 of the rotating knife for cutting the paper etc. is in a state where it cannot rotate, the blade 2 is also fixed. Thus, the Icnife is in a state where the paper etc. can be easily cut in a straight line.

On the other hand, if the paper etc. are required to be cut in a curved line, the user releases the pressing force acting on the locking button. When the pressing force acting on the locking button is released as aforementioned, the locking button 315 moves outside of the body 4 due to the restoring force of the leaf spring 33. Thus, the serrations 320 formed on the inner end of the locking button 315 are disengaged from the serrations 310 formed on the outer peripheral surface of the rotating shaft 31. Consequently, the rotating shaft 31 is free of the constraint of the locking button

315 and can freely rotate. Thus, the paper etc. can be easily cut in a curved line in the same way as the above embodiments.

On the other hand, the press pieces 350 formed on both sides of the locking button 315 on which pushing force of both ends of the opening in the annular leaf spring 33 upon restoration thereof acts, also prevent the locking button 315 from coming off the body 4.

A fourth embodiment of the present invention will be henceforth described.

FIG. 10 is a partially sectioned perspective view showing the interior constitution of a rotating Icnife for cutting paper etc. according to the fourth embodiment of the present invention. The rotating Icnife according to the fourth embodiment of the present invention is constructed such that the body 4 thereof is bent at an angle suitable for facilitating easy grip of the user.

At this time, the bent angle of the body 4 may be any angles as far as they make the rotating shaft 31 perpendicular to a surface of the paper etc. to be cut when the user comfortably grips the body 4 of the rotating Icnife. It is desirable that the angle a between the surface of the paper etc. and the rear portion of the body 4 be set within a range of 45 to 75 degrees , and most preferably, on 60 degrees.

On the other hand, the fourth embodiment of the present invention proposes another configuration and coupling structure of the cover which prevents the blade 2 from being exposed in front of the body 4. That is, in this case, grooves 450 between two ridges are formed on upper and lower portions of the outer peripheral surface of the front portion of the body 4, respectively. An inner surface of the cylindrical safety cover 7 is provided with a protruding ledge 700 which can be snap-fitted into each of the grooves 450. Thus, when the safety cover 7 is pulled toward the front portion of the knife, the protruding ledge 700 formed on the inner surface of the safety cover 7 is snap-fitted into the lower groove 450 in the front portion of the body 4 so as to prevent the exposure of the blade 2.

On the other hand, in order to use the knife, when the safety cover 7 is retracted in a direction opposite to the aforementioned direction, the protruding ledge 700 of the safety cover 7 is snap-fitted into the upper groove 450 in the front portion of the body 4 so as to expose the blade 2. Thus, the knife is ready to perform the cutting operation.

Further, although it is not shown in FIG. 10 for illustrating the fourth embodiment of the present invention, it is, of course, also possible to selectively fix and rotate the blade 2 in the rotating Icnife according to the fourth embodiment when the constitution of the third embodiment is applied to the rotating shaft. Next, a fifth embodiment of the present invention will be described.

FIG. 11 is a longitudinal sectional view showing the interior constitution of a rotating nife for cutting paper etc. according to the fifth embodiment of the present invention. In this case, instead of the safety cover for preventing the exposure of the blade 2 of the rotating knife, as a push button installed in the rear portion of the body 4 is pressed, the blade 2 protrudes out of the body 4 so that it is ready to cut the paper etc. in a curved line, or the blade 2 is retracted into the body 4 so as not to be exposed to the exterior.

That is, the rotating knife according to the fifth embodiment of the present invention includes the body 4 serving as the grip; the rotating shaft 31 rotatably installed within the body 4; the blade 2 which is detachably coupled with the rotating shaft 31 and exposed to the exterior in front of the body 4, and has the leading end disposed at the eccentric position at the predetermined distance from the center of rotation; the means for supporting the rotating shaft so that the rotating shaft 31 can be smoothly rotated within the body 4; and a means for retracting the blade 2 into the body 4 or advancing the blade 2 to be exposed in front of the body 4.

At this time, the means for supporting the rotating shaft includes a cylindrical bearing sleeve 8 installed on the inner peripheral surface of the front portion of the body 4 so as to move by a predetermined distance along the longitudinal direction of the body 4; and a bearing 32 installed between the bearing sleeve 8 and an outer peripheral surface of a portion of the rotating shaft 31.

Further, the means for advancing or retracting the blade 2 in the longitudinal direction of the body 4 includes a spring pressing projection 500 formed at a portion of an inner peripheral surface of the bearing sleeve 8 so as to constitute the means for supporting the rotating shaft; an elastic member such as a coil spring 5 fitted over the rotating shaft 31 so as to be positioned between the spring pressing projection 500 and the leading end of the body 4; a stopper 410 provided on a portion of the inner peripheral surface of the body 4 so as to define a retracted position of the bearing sleeve 8 toward the rear portion of the body 4; a thrust apparatus installed at the rear portion of the body 4; and a push button 9 coupled with a thrust shaft 80 of the thrust apparatus. At this time, the thrust apparatus is a well-known apparatus which is generally applied to a ballpoint pen or the like. In the thrust apparatus, fixing projections 420 are formed on the inner peripheral surface of the body 4 to be circumferentially spaced at a constant interval, and a catching projection 800 to be caught in the fixing projections 420 is formed on the thrust shaft 80. Thus, according to the number of times the push button 9 is pressed, the catching projection 800 can be alternately restrained or released.

In addition, a clip 10 is provided on the outer peripheral surface of the body 4 so that the user can put the knife in his/her pocket or between the leaves of a book in a state where the blade is not exposed to the exterior. It is apparent that the clip 10 may also be applied to the rotating knives 1 according to the first to fourth embodiments described above.

The rotating knife according to the fifth embodiment of the present invention constructed as such operates as follows.

First, if the user presses the push button 9 in order to use the rotating knife in a state where the blade is not exposed to the exterior, the rotating shaft 31 moves toward the front portion of the body 4, and then, the bearing 32 coupled with the rotating shaft, and the bearing sleeve 8 into which the bearing 32 is forcibly fitted are moved toward the front portion of the body 4.

Accordingly, the spring pressing projection 500 formed on the inner peripheral surface of the bearing sleeve 8 compresses the coil spring 5. At the same time, the catching projection 800 of the thrust apparatus moves toward the front portion of the body by means of the operation of the thrust apparatus provided within the body 4 of the rotating Icnife 1. Once the catching projection 800 is positioned in front of the fixing projections 420, the catching projection 800 is kept caught in front of the fixing projections 420 within the body 4 even though the pressing force acting on the push button 9 is eliminated. When the catching projection 800 is kept caught in front of the fixing projections 420 by means of the operation of the thrust apparatus as aforementioned, the blade 2 is kept exposed to the exterior in front of the body 4.

In the state where the blade 2 of the rotating Icnife 1 is exposed to the exterior in front of the body 4, when the user presses the push button 9 again, the catching projection 800 is released from the fixing projections 420 by means of the operation of the thrust apparatus.

In this way, when the catching projection 800 is released from the fixing projections 420, the coil spring 5 simultaneously pushes the spring pressing projection 500 formed on the inner peripheral surface of the bearing sleeve 8 by means of the restoring force thereof. At this time, the bearing sleeve 8, the bearing 32 forcibly fitted into and fixed to the bearing sleeve 8, and the rotating shaft 31 coupled with the bearing 32 are retracted together toward the rear portion of the body 4.

Accordingly, the rotating shaft 31 coupled with the bearing 32 is also retracted toward the rear portion of the body 4, and consequently, the blade 2 coupled with the front portion of the rotating shaft 31 is positioned within the body 4.

Here, since a portion of the inner peripheral surface of the body 4 is provided with the stopper 410 for defining the retracted position of the bearing sleeve 8, the retracted position of the blade 2 is also defined within the body 4. With the above operation of the rotating knife for cutting the paper etc. according to the fifth embodiment of the present invention, since the blade 2 is prevented from being exposed by means of the coil spring 5 and the thrust apparatus without an additional safety cover, the user can safely and conveniently use the rotating knife.

On the other hand, FIGS. 12a and 12b are perspective views showing other examples of the blade 2 employed in the rotating knife for cutting paper etc. of the present invention. In this case, the back of the blade 2 is also provided with an edge 3b.

That is, both upper and lower ends of the blade 2 take edges 3 a, 3b, respectively. If the blade 2 having such structure is applied to the above embodiments, the edge 3b on the side of the back of the blade can be usefully utilized when sharpening a pencil in a state where the blade 2 is fixed.

Here, the blade 2 may take the shape of a rhombus in section, as shown in FIG.

12a. Alternatively, it may take the shape of a plate in section which is edged at upper and lower ends thereof, as shown in FIG. 12b. As far as the leading end of the blade 2 is positioned at an eccentric position offset from the center of rotation, it is apparent that various modifications can be made to the shape of the blade.

In this case, as the push button 9 of a rear moving means 1000 installed in the rear portion of the body is turned, the blade 2 can be advanced toward the exterior of the front portion of the body so as to be able to cut the paper etc. in a straight or curved line, or can be retracted into the body so as not to be exposed to the exterior.

Further, in a state where the catching projection 800 formed in the rear moving means 1000 is positioned on a catching portion 1003 formed in a front moving means 1001, when the push button 9 is pressed, the rotating shaft 31 is pushed out of the -front portion of the body and a groove 1013 for detachably attaching the blade is flared so as to exchange the blade 2.

Hereinafter, the constitution of the rotating Icnife for cutting the paper etc. according to the sixth embodiment of the present invention will be described in detail. The rotating Icnife of the sixth embodiment is identical to that of the first embodiment in that it includes the body 4; the rotating shaft 31 installed rotatably within the body; the blade 2 detachably coupled with the rotating shaft 31 ; and the bearing for supporting the rotating shaft 31.

However, in the sixth embodiment, the groove 1013 for detachably attaching the blade is formed so as to easily and detachably attach the blade 2 by applying and releasing strangling force to and from the front portion of the rotating shaft 31.

Furthermore, a leading end of the rotating shaft 31 is formed with a tapered end 1012. Here, the diameter of the tapered end 1012 is gradually enlarged while extending toward the front portion of the body. On the other hand, the bearing for supporting the rotating shaft 31 is installed on the rear portion of the rotating shaft 31 and is in close contact with the outer peripheral surface of the rotating shaft 31 so as to ensure the rotation of the rotating shaft 31. The bearing includes a rear bearing 32 which moves together with the rotating shaft 31 in an axial direction of the body 4, and a front bearing 1010 which is installed in the front portion of the rotating shaft 31 and is coupled with the outer peripheral surface of the rotating shaft 31 with a predetermined gap therebetween.

Here, since the front bearing 1010 is spaced apart at the predetermined gap from the outer peripheral surface of the rotating shaft 31, the movement of the rotating shaft 31 in the axial direction of the body can be allowed. However, since the leading end of the rotating body 31 is formed as the tapered end 1012 of which diameter is gradually increased while extending toward the front portion of the body, when the rotating shaft 31 is moved toward the rear portion of the body by means of predetermined force, the tapered end 1012 comes into close contact with the front bearing 1010 and is subject to the strangling force from the front bearing so as to the compress the groove 1013 for detachably attaching the blade. Moreover, the inner surface of the body 4 is formed with an axial guide way 1016, and the leading end of the body is formed with a breakaway preventing projection 1014 for preventing the front bearing 1010 from coming off the interior of the body. The breakaway preventing projection 1014 is formed to extend radially toward the interior of the body 4.

On the other hand, the sixth embodiment further includes additional components, which are not included in the first embodiment, in order to advance or retract the blade 2 within the body and to easily exchange the blade 2.

That is, the rear portion of the rotating shaft 31 is provided with the front moving means 1001 coupled with the rear bearing 32 in order to move axially the rotating shaft 31 within the body.

Here, the front moving means 1001 is provided with the catching portion 1003 on the outer peripheral surface thereof, and a forward-sloped portion 1004 which forwardly slopes and extends from both ends of the catching portion 1003. The front moving means 1001 is guided by the axial guide way 1016 formed on the inner surface of the body so as to be moved in the axial direction of the body 4.

Further, the additional rear moving means 1000 for moving the front moving means 1001 is provided in the rear of the front moving means 1001.

The rear moving means 1000 is provided with the catching projection 800, which is formed to be caught on the catching portion 1003 and the forward-sloped portion 1004 formed in the front moving means 1001, and the push button 9 which protrudes beyond the rear portion of the body.

Moreover, a first spring 1006 is installed between the front bearing 1010 and the front moving means 1001. The first spring 1006 applies restoring force to the rotating shaft 31 when the rotating shaft 31 is moved forwardly in order to exchange the blade 2.

In addition, a second spring 1008 is installed between the front moving means 1001 and the body.

The second spring 1008 applies force for retracting the blade 2 into the body. The rotating Icnife according to the sixth embodiment of the present invention constructed as such operates as follows.

When the push button 9 is turned, the catching projection 800 formed in the rear moving means 1000 turns along the forward-sloped portion 1004 formed on the outer peripheral surface of the front moving means 1001. At this time, the forward-sloped portion 1004 is formed to slope forwardly on the outer peripheral surface of the front moving means 1001 as described above, and the catching projection 800 is caught on the forward-sloped portion 1004.

When the catching projection 800 is turned from the position thereof as shown in FIG. 13, a position where the catching projection 800 is caught on the forward-sloped portion 1004 is changed and the front moving means 1001 is moved axially toward the rear portion of the body 4 by means of the restoring force of the second spring 1008.

Accordingly, the rear bearing 32 coupled with the front moving means 1001 is also moved toward the rear portion of the body 4. Further, the rotating shaft 31 is also moved toward the rear portion of the body since it is closely coupled with the rear bearing 32.

As a result, the blade 2 installed in the front portion of the rotating shaft 31 is retracted into the body.

On the other hand, when the push button 9 is rotated with the blade 2 retracted into the body, the blade 2 is advanced to be exposed in front of the body, contrary to the retracting operation of the blade 2. Further, the push button 9 is pressed with the catching projection 800 positioned on the catching portion 1003, the front moving means 1001 is moved forwardly.

Accordingly, the rear bearing 32 coupled with the front moving means 1001 is also moved toward the front portion of the body 4. Further, the rotating shaft 31 closely coupled with the rear bearing 32 is also moved toward the front portion of the body.

As a result, the tapered end 1012 strangled with the front bearing 1010 is released forwardly from the front bearing 1010 and the groove 1013 for detachably attaching the blade is opened so that the blade 2 can be exchanged.

Next, a seventh embodiment of the present invention will be described. FIG. 14 is a longitudinal sectional view showing the interior constitution of a rotating knife for cutting paper etc. according to the seventh embodiment of the present invention.

According to the seventh embodiment, a rear body 5 is turned in order to retract the blade 2 into the body and to advance it to the exterior of the front portion of the body, contrary to the sixth embodiment in which the turning of the push button 9 causes the blade 2 to be retracted into the body or to be advanced to the exterior of the front portion of the body.

To this end, the seventh embodiment is constructed by making modifications to the constitution of the sixth embodiment as follows. That is, the body consists of a front body 6 and the rear body 5, which are coupled rotatably with each other.

Further, an inner surface of the rear body 5 is formed with an axial guide groove 351, and the rear moving means 1000 is formed with a rotating projection 1020 which is caught in the guide groove 351. The rotating projection 1020 is rotated together with the rear moving means 1000 upon turn of the rear body 5. However, since the guide groove 351 guides the axial movement of the rear moving means 1000, the rear moving means 1000 can be moved in the axial direction of the body by pressing the push button.

With such constitution, since the rotating knife according to the seventh embodiment is operated such that by turning the rear body 5 instead of the push button 9 in the sixth embodiment, the blade 2 can be retracted into the body or be advanced to the exterior of the front portion of the body in the same way as the sixth embodiment, detailed description of the operation of the seventh embodiment will be omitted.

Furthermore, since the opening operation of the groove 1013 for detachably attaching the blade is identical to that of the sixth embodiment, detailed description thereof will be omitted.

As described above, the present invention improves the structure of a knife for cutting paper etc. such that it can be conveniently used for cutting the paper etc. in a straight and curved line by selectively fixing or rotating the blade in accordance with a required shape to be cut.

Accordingly, upon cutting of the paper etc. in a curved line having a certain curvature or a circular line, the rotating knife for cutting the paper etc. according to the present invention allows only the blade to be moved smoothly with the paper etc. remained stationary, so that the paper etc. can be conveniently cut in a desired form. Thus, workability and safety thereof in operation can be enhanced.

That is, the rotating lαiife for cutting the paper etc. according to the present invention can cut the paper etc. in a curved line without an additional auxiliary means, contrary to a conventional stationery knife. Therefore, a user can experience a high feeling of satisfaction particularly when cutting the paper etc, in a curved line. In addition, if the body of the rotating Icnife according to the present invention takes the shape of a circle in section, since the user can easily handle it and does not suffer from a pain resulted from work for a long time, the user can have an advantage of convenience.

On the other hand, although it has not separately shown and illustrated, the rotating Icnife for cutting the paper etc. of the present invention is provided with the conventional rotary-type pencil sharpener at the rear portion of the body.

The present invention is not limited to the above embodiments, and it is apparent that various modifications and changes can be made thereto without departing from the scope of the invention.

Claims

What is claimed is:

1. A rotating knife for cutting paper etc., comprising: a body; a rotating shaft rotatably installed within said body; a blade which is detachably coupled with said rotating shaft and exposed to the exterior in front of said body, and has a leading end disposed at an eccentric position spaced apart at a predetermined distance from a center of rotation; and a means for supporting said rotating shaft so that said rotating shaft can be smoothly rotated within said body.

2. The rotating Icnife for cutting the paper etc. as claimed in claim 1, wherein said means for supporting said rotating shaft is at least one bearing installed in an axial direction of said body between an inner peripheral surface of said body and an outer peripheral surface of said rotating shaft.

3. The rotating knife for cutting the paper etc. as claimed in claim 1, wherein said means for supporting said rotating shaft includes a rear distal end of said rotating shaft; and a spherical support provided in a rear portion of said body so as to be in point contact with said rear distal end of said rotating shaft.

4. The rotating knife for cutting the paper etc. as claimed in claim 1, further comprising a means for locking said rotating shaft so that a user can selectively constrain rotation of said rotating shaft.

5. The rotating knife for cutting the paper etc. as claimed in claim 4, wherein said means for locking said rotating shaft includes a fixing member for preventing said rotation which is installed movably along an axial direction of said body within said body and has a polygonal through-hole formed at the center thereof; and a tapered portion which is formed at a distal end of said rotating shaft so that said rotating shaft is constrained in said fixing member when said tapered portion is fitted into said polygonal through-hole of said fixing member.

6. The rotating Icnife for cutting the paper etc. as claimed in claim 5, wherein a rear portion of said body is formed with a rectangular guiding groove having a predetermined length along said axial direction of said body; a rear end of said rectangular guiding groove is formed with a fixing groove extending in a direction perpendicular to said axial direction of said body; and one side of an outer periphery of said fixing member is further provided with an operating knob which protrudes through and moves along said rectangular guiding groove formed in said body in said axial direction; whereby when said operating Icnob is positioned at a front portion of said rectangular guiding groove, said rotation of said rotating shaft can be prevented and said blade can be constrained; and when said operating knob is positioned in said fixing groove, said blade can freely rotate.

7. The rotating knife for cutting the paper etc. as claimed in claim 4, wherein said means for locking said rotating shaft includes serrations formed on an outer peripheral surface of a front portion of said rotating shaft to be detachably coupled with said blade; a locking button installed through said body and formed with serrations at an inner end thereof so as to be mated with said serrations of said rotating shaft; and an annular leaf spring installed within said body and spaced apart at a distance radially and outwardly from said rotating shaft so as to push said locking button radially and outwardly.

8. The rotating Icnife for cutting the paper etc. as claimed in claim 7, wherein both sides of said locking button are formed with protruding press pieces for pressing both ends of an opening in said annular leaf spring as said user presses said locking button.

9. The rotating knife for cutting the paper etc. as claimed in claim 1, wherein a rear portion of said body serving as a grip is bent with respect to a front portion of said body so that an angle between a surface of said paper etc. and said rear portion of said body is set within a range of 45 to 75 degrees in a state where said blade and said rotating shaft are perpendicular to said surface of said paper etc. with said body gripped by the user.

10. The rotating Icnife for cutting the paper etc. as claimed in claim 1, further comprising a safety cover which can be detachably attached to said body and prevent said blade from being exposed to the exterior when coupled with said body.

11. The rotating Icnife for cutting the paper etc. as claimed in claim 10, wherein an inner surface of said safety cover is provided with a protruding ledge; and grooves into which said protruding ledge can be fitted are formed on upper and lower portions of an outer peripheral surface of a front portion of said body, respectively, whereby when said safety cover is pulled toward a front portion of said rotating knife, said protruding ledge formed on said inner surface of said safety cover is snap-fitted into said lower groove in a front portion of said body so as to prevent the exposure of said blade.

12. The rotating Icnife for cutting the paper etc. as claimed in claim 1, wherein both upper and lower ends of said blade take cutting edges, respectively.

13. The rotating Icnife for cutting the paper etc. as claimed in claim 12, wherein said blade takes the shape of a rhombus or a plate in section taken along a center line of said blade.

14. A rotating Icnife for cutting paper etc., comprising: a body serving as a grip; a rotating shaft rotatably installed within said body; a blade which is detachably coupled with said rotating shaft and exposed to the exterior in front of said body, and has a leading end disposed at an eccentric position spaced apart at a predetermined distance from a center of rotation; a cylindrical bearing sleeve installed on an inner peripheral surface of a front portion of said body so as to move by a predetermined distance along a longitudinal direction of said body; a bearing installed between said bearing sleeve and an outer peripheral surface of a portion of said rotating shaft; and a means for retracting said blade into said body or advancing said blade to be exposed in front of said body.

15. The rotating Icnife for cutting the paper etc. as claimed in claim 14, wherein said means for advancing or retracting said blade includes a spring pressing projection formed at a portion of an inner peripheral surface of said bearing sleeve; an elastic member such as a coil spring fitted over said rotating shaft so as to be positioned between said spring pressing projection and a leading end of said body; a stopper provided on a portion of an inner peripheral surface of said body so as to define a retracted position of said bearing sleeve toward a rear portion of said body; a thrust apparatus installed at said rear portion of said body; and a push button coupled with said thrust apparatus for activating it.

16. The rotating Icnife for cutting the paper etc. as claimed in claim 15, wherein a groove for detachably attaching said blade is formed at a front portion of said rotating shaft; a leading end of said rotating shaft is formed with a tapered end of which diameter is gradually increased while extending forwardly; said bearing includes a rear bearing which is closely coupled with an outer peripheral surface of a rear portion of said rotating shaft, and a front bearing which is coupled with an outer peripheral surface of said front portion of said rotating shaft with a predetermined gap therebetween, allows said rotating shaft to be moved in an axial direction of said body and applies strangling force to said tapered end; an inner surface of said body is formed with an axial guide way, and said leading end of said body is provided with a breakaway preventing projection which is formed to extend radially toward the interior of said body and prevents said front bearing from coming off the interior of said body; and said rotating knife further includes a front moving means which is coupled with said rear bearing, is provided with a catching portion on an outer peripheral surface thereof and with a forward-sloped portion that forwardly slopes and extends from both ends of said catching portion, and is guided by said axial guide way so as to be moved in said axial direction of said body; a rear moving means which is provided with a catching projection formed to be caught on said catching portion and said forward-sloped portion and with said push button protruding beyond said rear portion of said body; a first coil spring positioned between said front bearing and said front moving means and fitted over said rotating shaft; and a second spring positioned between said front moving means and said body; whereby when said push button is turned, said catching projection formed in said rear moving means turns along said forward-sloped portion formed on said outer peripheral surface of said front moving means, so that said front moving means is moved in said axial direction of said body and said blade is thus retracted into said body or advanced to be exposed in front of said body; and when said push button is pressed with said catching projection positioned on said catching portion, said front moving means is moved forwardly and said tapered end strangled with said front bearing is released from said front bearing so that said groove for detachably attaching the blade is opened so as to be able to exchange said blade.

17. The rotating Icnife for cutting the paper etc. as claimed in claim 16, wherein said body consists of a front body and a rear body, which are coupled rotatably with each other; an inner surface of said rear body is formed with an axial guide groove; and said rear moving means is formed with a rotating projection which is caught in said guide groove; whereby when said rear body is turned, said catching projection formed in said rear moving means turns along said forward-sloped portion formed on said outer peripheral surface of said front moving means, so that said front moving means is moved in said axial direction of said body 4 and said blade is thus retracted into said body or advanced to be exposed in front of said body; and when said push button is pressed with said catching projection positioned on said catching portion, said front moving means is moved forwardly and said tapered end 1012 strangled with said front bearing is released from said front bearing so that said groove for detachably attaching the blade is opened so as to be able to exchange said blade.