Cutter

Abstract: A cutter (11) for cutting through a thing such as an envelope (13) at a given distance (H) from its edge (17) approximately straight and parallel to the edge. An edge portion of a thing to be cut such as an envelope is put on a sliding surface (16), and then it is slided with its edge remaining in contact with a sliding side (18) perpendicular to the sliding surface. The thing to be cut is pressed against the sliding surface with a press means when cut. And it is slashed with a blade edge at a given distance from the envelope edge approximately straight and parallel to the edge.

Description: [ BACKGROUND OF THE INVENTION] [ FIELD OF THE INVENTION] This invention relates to a cutter for opening an envelope, for example, at a given distance from its edge approximately straight and parallel to the edge. [ DESCRIPTION OF THE PRIOR ART] In order to open an envelope, we conventionally adopt a method of breaking open a fastened flap with a knife, and another method of cutting off the edge portion with a cutter. The former method, as shown in Fig. 11, is of inserting a knife 1 into a gap in the fastened flap 2a of an envelope 2 and breaking open the flap. The latter method, as shown in Fig. 12, is of cutting off the edge portion at the opening side from an envelope with a letter opener. To describe the latter in detail, the edge portion at the opening side is inserted into a sliding groove 4 of a body 3, and it is slided in the right direction in the drawing. After the switching on of a switch 5 by contact with the envelope, a round blade 6 turns round and cuts off the edge portion, which is being carried in the arrow direction by the turning of the blade during the cutting. However, both the methods have the following drawbacks. The former method can not be adopted in the case of no gap in the flap 2a to insert a knife, or in the case of too much time to insert. Furthermore, the knife 1 needs some heed to use or hold and it is unhandy to carry about. In stead of the knife 1 mostly made of metal, a plastic or wooden knife may be blunter under the quality of paper and produce a fluffy and ugly cut opening. The latter method, though automatic ad convenient, has the following problems. When it is cut off with the round or gear-like blade 6, the envelope remains apart from the sliding surface ad unstable to cut owing to no press of the envelope against the sliding surface of the groove 4. Therefore, it is impossible to cut off the enveloppe at a given distance from the edge. Other problems are those of noise by an electric motor and the large-size of the letter opener. An object of the invention is to provide a cutter for cutting through an edge portion of any thing to be cut such as an evelope always at a given distance from its edge straight and parallel to the edge. However, US-A-4 530 154 discloses a cutter for cutting through a enveloppe at a given distance from its edge comprising: a cutter body (14), a sliding floor (36), a sliding side (38) formed approximately perpendicular to said sliding floor, a blade (20) disposed on the ceiling opposite said sliding floor and disposed parallel to said sliding side, and a blade edge facing slantingly downward for pressing said thing against said sliding floor in cutting. SUMMARY OF THE INVENTION A cutter of the invention for cutting through a thing to be cut such as an enveloppe at a given distance from its edge approximately straight and parallel to the edge comprises: a cutter body ; a sliding floor for sliding an edge portion of said thing thereon formed in said body ; a sliding side for keeping said edge in contact therewith and slided thereon formed approximately perpendicular to said sliding floor ; plural blades, for cutting though said thing which are disposed on the ceiling opposite said sliding floor and disposed parallel to said sliding side ; a press means for pressing said thing against said sliding floor in cutting ; and an escape means for escaping said thing toward the side opposite tips of said blades in porportion to the thickness of said thing, being a concave formed in a sliding floor under said tips. It is characterized in that the blades are disposed in series and in that the blades at the upper side in the sliding direction are more distant from said sliding floor than the blades at the down side in the sliding direction. Furthermore, a cutter of the invention is characterized in that the sliding side is curved approximately from a part of the sliding side facing the main blade downward. Furthermore, a cutter of the invention is characterized in that the blade is exchangable. Furthermore, a cutter of the invention is characterized in that the blade can be used both for the downward sliding direction and for the upward. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a letter opener according to a first embodiment of the invention. Fig. 2 is a front view of a letter opener according to a first embodiment of the invention. Fig. 3 is a left side view of a letter opener according to a first embodiment of the invention. Fig. 4 is a top view of a letter opener according to a first embodiment of the invention. Fig. 5 is a perspective view in use of a letter opener according to a first embodiment of the invention. Fig. 6 shows an enlarged partial front sectional view of a letter opener according to a second embodiment of the invention. Fig. 7 shows a part correspondent to that in Fig. 6 of a letter opener according to a third embodiment of the invention. Fig. 8 is a front view of a blade according to a fourth embodiment of the invention. Fig. 9 is a front view of a blade according to a fifth embodiment of the invention. Fig. 10 is a top sectional view of a letter opener according to a sixth embodiment of the invention. Fig. 11 is a perspective view showing a conventional method for opening an envelope. Fig. 12 is a perspective view of a conventional letter opener. [DETAILED DESCRIPTION] The invention is described in greater detail hereinafter in relation to the attached drawings. Fig. 1 through Fig. 5 show a embodiment of the application of a cutter to a letter opener. A letter opener of this embodiment comprises a nearly rectangular resinous body 11, a sliding groove 12 channeled at the side part of the body 11. An edge portion 14 at the opening side of an envelope 13 is inserted into the groove 12 and then slided. And a sliding floor 15 for putting on and sliding the edge portion 14 of the envelope 13 is formed at a lower part of the groove 12. And also a given-thick cushion 16 served as an escape means is attached to the sliding floor 15. A sliding side 18 for remaining in contact and sliding the edge 17 of the envelope 13 is formed at the side wall perpendicular to the sliding floor 15 of the groove 12. A sub blade 19 ( at the upper or left side in the rightward sliding of the envelope ) and a main blade 20 (at the lower or right side ) are disposed on the ceiling of the groove 12. These blades 19 and 20 are paralell to the sliding side 18 and in series. The blades 19 and 20 are shaped almost like triangle and each tip 19a and 20a of the blades juts out toward the cushion 16 or downward. As shown in Fig. 3, a distance H between the blades and the sliding side 18 is predetermined slight ( 1mm to 2 mm, for example ). The tip 20a of the main blade 20 is located approximately in contact with the cushion 16, while the tip 19a of the sub blade 19 is upper than the tip 20a. The blade edges 19b and 20b face slantingly-left-downward as shown in Fig. 2. And next, various advantageous functions of a letter opener constituted as illustrated above will be described. In order to open an envelope 13, an edge portion 14 to be opened of the envelope 13 is inserted into the sliding groove 12 and an edge 17 of the portion 14 is contacted with the sliding side 18 as shown in Fig. 5. With the edge 17 remaining in contact with the sliding side 18, the envelope 13 is slided rightward as shown by the arrow in Fig 5. The tip 19a of the sub blade 19 is first thrust small into the front side of the envelope 13, which is twofold, and then the tip 20a of the main blade 20 is thrust deep thereinto, and the front side of the envelope is cut through. The slantingly-left-downward disposition of the blade edges 19b and 20b makes it possible to cut fixedly, because the edge portion 14 of the envelope 13 is pressed against the cushion 16, not as in the prior art wherein the envelope edge portion 14 remains apart from the sliding surface when cut. In the present embodiment, the blade edges 19b and 20b facing slantingly-left-downward are served as a press means. As a matter of course, a press member such as a spring may be served as a press means except the blades 19 and 20. Since the press member presses the cushion 16, the edge portion 14 of the envelope escapes downward, and accordingly the back side of the envelope is seldom cut through completely. And the thrust of the sub and main blades 19 and 20 into the envelope during the cutting permits to be cut through straight because the envelope 13 is firmly put on the surface and the envelope edge 17 is slided always in touch with the sliding side 18. Furthermore, since the distance H between the blades and the sliding side 18 is predetermined slight (1 mm to 2 mm, for example ), the envelope is opened quickly at a short distance from the envelope edge 17regardless of the tickness of the envelope. And furthermore, the disposition of the tip 19a of the sub blade 19 located upper ( or more distant from the sliding surface ) than the tip 20a of the main blade 20 permits a gradual cutting, namely the first shallow thrust and cutting by the sub blade 19 and the second deep thrust and cutting by the main blade 20. And accordingly, the envelope 13 can be cut through smoothly and quickly regardless of the thickness of the envelope. In the case of the cutting with the main blade 20 only, it is difficult for the sole blade 20 to cut through the front or back side of the envelope completely because of a strong resistance and separation of the envelope edge from the sliding side 18. And thus, since the front or back side only of the twofold envelope 13 is cut through, no cut-off scrap is produced to cast away. And the contents of the envelope are easily taken out from the cut slit by holding the edge portion 14 of the envelope with one's hand. It is of course easy to put back the contents thereinto. Even if the cut slit is turned downward, the contents would not fall off because the edge portion 14 of the envelope is not cut off from the envelope itself. Fig. 6 shows a second embodiment according to the invention. An escape means in the second embodiment is different from that in the first embodiment. A concave 15a is formed in the sliding floor 15 under the blade tips 19a and 20a and an pushing-up member 23 with a spring 22 is disposed therein as shown in Fig. 6. The envelope 13 escapes downward by the descent of the pushing-up member 23 in connection with the shrinkage of the spring when cut, so that the back side of the twofold envelope can not be cut through. Fig. 7 shows a third embodiment according to the invention. An escape means in the third embodiment is different from those in the first and second embodiments. A concave 15b as an escape means is formed in the sliding floor 15 under the blade tips 19a and 20a as shown in Fig. 7. The envelope 13 escapes toward the concave 15b when cut, so that the back side of the envelope can not be cut through. In order to overcome the problem of some abrasion of the blade edge owing to the frequent using and to cut through completely, the tips 19a and 20a can be a little inserted into the cavity of the concave 15b. Fig. 8 shows a fourth embodiment according to the invention. Referring now to Fig. 8, there is disposed a sole triangle-shaped blade 24 having two blade edges 24a and 24a. This blade 24 allows to slide and slash the envelope in both the directions in the groove 12, and it is irrespective of the right-handed or the left-handed. Fig. 9 shows a fifth embodiment according to the invention. In this embodiment, there is disposed a half-round-shaped blade 25 by which the envelope 13 can be slided and slashed either rightward or leftward. Fig. 10 shows a sixth embodiment according to the invention. In this embodiment, a straight sliding side 18 is curved from the nighborhood a little passing the place on the sliding side 18 behind the main blade 20. When the envelope is slided and slashed with the envelope edge 17 remaining in contact with the sliding side 18, the envelope edge 17 receives force clockwise centering around the tip 20b of the main blade 20 in accordance with the sliding at the curved portion 18a. That is, the left side of the envelope edge 17 is pressed against the side 18 and 18a stronger in sliding. And accordingly, the envelope 13 is cut through always at a given distance from the envelope edge without the separation of the edge 17 from the sliding side 18 and 18a. Each blade 19, 20, 24, and 25 as expendables can be made exchangeable to be more economical. Furthermore, the equipment of a weigher, measure, or mirror with the letter opener body 11 makes the application diversified. Besides the cushion 16 and the concave 15b, for example, in the above embodiments, a given gap as an escape means may be formed between the tip 19a and the sliding floor 15. This gap ensures that the edge portion to be opened of the envelope 13 is not completely cut off apart from the envelope. As a matter of course, a cutter of the present invention is not limited to the letter opener in the embodiments mentioned above. To sum up itemizedly, a cutter according to the invention first can press the edge portion of a thing to be cut against the sliding floor and cut it through stably not as in the prior art wherein the edge portion remains apart from the sliding floor and unstable to cut. Second, the disposition of an escape means for escaping a thing to be cut toward the side opposite the tip of a blade permits to slash the front ( or back ) side only of the twofold envelope in proportion to the thickness of the envelope. And consequently, it produces no cut-off scrap to cast away as in the prior art. The contents of the envelope can be easily taken out from the cut slit by holding the edge side with one's hand. And also it is easy to put it back thereinto in the same way. The contents would not fall off from the cut slit even if it is turned downward because the edge portion is not completely cut off apart from the envelope. Third, plural blades are disposed in series and the blade tip at the upper ( or left ) side is located more distant from the sliding floor than that at the down ( or right ) side, so that the envelope is thrust gradually deeply and slashed smoothly. Furthermore, plural blades permits the envelope to be guided straight. Fourth, the formation of the sliding side curved from the neighborhood behind the blade at the down ( or right ) side produces force for pressing the envelope edge against the sliding side, so that the envelope can be cut through always at a given distance from the envelope edge. Fifth, an exchangeable blade is more economical than expendable one. Sixth, the equipment of various functions with the cutter spreads the field of use. Seventh, a blade with two blade edges or round edge permits the envelope to be cut bidirectionally.

Claims: A cutter for cutting through a thing to be cut such as an enveloppe (13) at a given distance from its edge approximately straight and parallel to the edge comprising: a cutter body (11) ; a sliding floor (15) for sliding an edge portion of said thing thereon formed in said body; a sliding side (18) for keeping said edge in contact therewith and slided thereon formed approximately perpendicular to said sliding floor ; a blade with a tip, for cutting through said thing which is disposed on the ceiling opposite said sliding floor and disposed parallel to said sliding side; a press means for pressing said thing against said sliding floor in cutting ; and an escape means for escaping said thing toward the side opposite said tip of said blade in proportion to the thickness of said thing, being a concave formed in a sliding floor under said tip, characterized in that plural said blades (19, 20) are disposed in series and in that the blade at the upper side in the sliding direction is more distant from said sliding floor (15) than the blade at the down side in the sliding direction. A cutter according to claim 1, wherein said sliding side (18) is curved from the neighborhood facing said down blades. A cutter according to claim 1, wherein said blades (19, 20) are exchangeable. A cutter according to claim 1, wherein said blades (19, 20) can cut through said thing bidirectionnally in sliding.

Inventors: IKEDA SHUNSUKE, IKEDA, SHUNSUKE
Applicants: SICO INC, SAIKO INC.
Application year: 1991
Main classification: B43M7
IPC codes: B26D1, B43M7