Scissors having rustproof blades |
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申请号 | EP06122802.9 | 申请日 | 2006-10-24 | 公开(公告)号 | EP1795316A1 | 公开(公告)日 | 2007-06-13 |
申请人 | Ryota, Kusanagi; | 发明人 | Hirai, Akira; | ||||
摘要 | When ceramic is used for blades of scissors, shear stress is concentrated on a pivot, and when the blades are fixed by a typical metal bolt, the bolt becomes worn out causing the scissors to rattle, due to the ceramic having hardness larger than the metal bolt, which affects the durability of the scissors. The present invention provides a pair of scissors 1 that includes a pivot 2 rotatably supporting top and bottom blades 1A and 1B, in which the blades 1A and 1B are made of a sintered ceramic, through holes lAa and 1Ba are formed at the pivot 2, a ceramic ring 2a is rotatably inserted in the through holes 1Aa and 1Ba, a fixing shaft 2a passes through the ceramic ring 2a to be fixed, and the ceramic ring 2a contains CuO. |
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权利要求 | |||||||
说明书全文 | The present invention relates to a pair of scissors including rustproof top and bottom blades and a pivot rotatably supporting the blades to cut a material by a shearing operation between the blades, more particularly, to a pair of scissors in which top and bottom blades are formed of a rustproof metal and a ceramic ring is inserted into the pivot to increase the durability. In the related art, a pair of scissors is used for cutting a material, such as a sheet, and also for various purposes such as gardening, cooking, etc. A thread fastening means using a bolt is widely used as a fixing mechanism at a pivot. However, since a thread fastening force affects the opening/closing force during cutting a material, when a bolt is firmly fastened so as to prevent loosening, the two blades become too close due to the thread-fastening force to operate. Accordingly, a method using a shoulder screw to fix a fastening position has been used. However, when a ceramic is used for blades of scissors, the shear stress of the scissors is concentrated on the pivot. When the blades are fixed by a typical metal bolt, a hardness of the ceramic is larger than that of the metal bolt. Therefore, the bolt becomes worn out, which causes the scissors to rattle, and affects the durability of the scissors. Further, the metal bolt is worn out and rusted allowing rust to adhere to the ceramic blades, which affects the appearance and maintenance of sanitation of the ceramic that is esthetic in itself. For example, in However, as for the scissors disclosed in Furthermore, as for the bipolar clamp 10 disclosed in In order to overcome the above problems, a pair of scissors having rustproof blades according to the embodiment of the invention includes a pivot rotatably supporting top and bottom blades to cut a material by the blades' reciprocal shearing, in which the blades are made of Ti alloy or sintered ceramic having Vickers hardness of 1000 Hv or more, through holes are formed at the pivot, a ceramic ring is rotatably inserted in the through holes, a fixing shaft passes through the ceramic ring to be fixed, and the ceramic ring contains CuO to improve antibiotic function. The above and other features and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which:
Hereinafter, detailed description will be given of a pair of antirusting scissors according to an embodiment of the present invention with reference to accompanying drawings. The present invention relates to a pair of scissors including rustproof top and bottom blades 1A and 1B and a pivot 2 rotatably supporting the blades to cut a material by a shearing operation between the two blades, in particular, to a pair of scissors in which top and bottom blades are formed of a rustproof metal and a ceramic ring 2a is inserted in the pivot to increase the durability. According to an embodiment of the invention, a pair of scissors 1 includes a pivot 2 rotatably supporting the top and bottom blades 1A and 1B to cut a material by using shearing operation between the blades. In this case, the blades 1A and 1B are formed of a Ti alloy, through holes 1Aa and 1Ba are formed at each pivot 2, and the ceramic ring 2a is rotatably inserted in the through holes 1Aa and 1Ba while a fixing shaft 2b passes through the ceramic ring 2a so as to be fixed. According to another embodiment of the invention, a pair of scissors 1 includes a pivot 2 rotatably supporting the top and bottom blades 1A and 1B to cut a material by shearing operation between the blades. The blades 1A and 1B are made of a sintered ceramic having Vickers hardness of 1000 Hv or more, through holes 1Aa and 1Ba are formed at the pivot 2, and a ceramic ring 2a is rotatably inserted in each of the through holes 1Aa and 1Ba, while a fixing shaft 2b passes through the ceramic ring 2a so as to be fixed. According to another embodiment of the invention, in the above-mentioned scissors, the ceramic ring 2a contains CuO to maintain an antibiotic function. Known scissors generally use quench-hardened blades, but a fixing shaft that is inserted into through holes formed through blades for different types of scissors for gardening, cooking, etc. is generally formed of a material having hardness lower than the blades. Because the entire shear stress in the scissors is applied to the fixing shaft, as the scissors are used repeatedly, the fixing shaft is worn out by sliding between the fixing shaft and the inner surfaces of the through holes of the blades having higher hardness than the fixing shaft, which causes rattling. As a result, the gap between the two blades is increased and thus it becomes difficult to cut material with the scissors. When a pair of scissors is used for cutting plants such as garden shears or for cutting meat, etc. such as cooking scissors, acid, base, or salt contained in sap or meat juice exuded by cutting permeates into the pivot of the two blades and corrodes or rusts the blades and the fixing shaft, so that they shorten the durability of the scissors. In addition, the pivot of the scissors is exposed to an unsanitary environment where various bacteria can easily propagate due to remaining water or sap. Therefore, scissors having rustproof blades according to an embodiment of the invention is provided to increase the durability while keeping the pivot sanitized, which are the most important parts in the structure of the scissors. The scissors according to an embodiment of the invention includes rustproof top and bottom blades 1A and 1B that are longitudinally provided with cutting portions 1Aa and 1Bb for cutting a material, handles 1Ac and 1BC that are provided at the ends of the blades for holding and providing shear force to the cutting portions, and a pivot 2 that are formed in the middle portion of each blade where the blades symmetrically cross to rotatably support the blades. The top and bottom blades 1A and 1B are made of a Ti alloy and through holes 1Aa and 1Ba into which a ceramic ring 2a (described below) is inserted are formed at each pivot 2. As shown in FIGS. 2 and 3, the ceramic ring 2a is a ring made of a ceramic having inner and outer diameters, whose thickness is the same or larger than the sum of the thicknesses of the top and bottom blades 1A and 1B at the pivot. Further, the outer diameter of the ceramic ring is smaller than the inner diameters of the through holes 1Aa and 1Ba, and the fixing shaft 2b (described below) can pass through the inner diameter of the ceramic ring. The through holes 1Aa and 1Ba are formed through the top and bottom blades 1A and 1B, respectively, and the ceramic ring 2a is inserted into the through holes. The fixing shaft 2b passes through the ceramic ring 2a inserted in the through holes 1Aa and 1Ba of the top and bottom blades 1A and 1B so as to be fixed thereto. In the present embodiment, a shaft portion 2bb protrudes from the center of a circular plate flange 2ba and is fixed by a nut 2bc that is fastened to the screw threaded at the end portion of the shaft portion 2bb, and flat washers 2bd are interposed between the flange 2ba and the top blade 1A, and the nut 2bc and the bottom blade 1B. However, the fixing shaft 2b is not specifically limited to the above-mentioned shaft as long as the shaft passes through the ceramic ring 2a. According to another embodiment of the invention, the top and bottom blades 1A and 1B are made of a sintered ceramic having Vickers hardness of 1000 Hv or more instead of a Ti alloy, and the other characteristics are the same as in the above embodiment, thus the description will be omitted. Further, the ceramic ring 2a may contain CuO that has an antibiotic function as well-known in the art to add the antibiotic function to the pivot 2 which are easily dirty. The hardness of the blades made of a carbon steel of known scissors depends on the manufacturing conditions, and the Vickers hardness thereof is generally 800 Hv or less, while the Vickers hardness of a fixing shaft used in related art is 500 Hv or less. However, Vickers hardness of alumina ceramic for the ceramic ring 2a according to the embodiments of the invention, i.e. 1200 Hv or more and Vickers hardness of oxidized zirconium ceramic is 1600 Hv or more, which are considerably larger than that of known blades. Therefore, abrasion due to sliding on the insides of the top and bottom blades 1A and 1B at the pivot is not caused in the ceramic ring 2a. The hardness of the Ti alloy used for the top and bottom blades 1A and 1B according to the embodiments of the invention, which has a rustproof characteristic, is substantially the same as carbon steel and 800 Hv or less, thus does not wear out the ceramic ring 2a. The ceramic ring 2a is mainly formed of a sintering-bonded structure of sub micron particles and the surface after the sintering-bonding is smooth and does not cause abrasion and sticking due to sliding on a metal surface, thereby allowing the ring to maintain accuracy for a very long time due to corrosion resistance. Further, when the ceramic ring 2a is used, the inner diameter of the ring is larger than the fixing shaft 2b passing through the ring, as a result the shear stress is dispersed due to the diameter being larger than the shaft. Accordingly, the abrasion is reduced by the increased diameters of the through holes 1Aa and 1Ba and the ceramic ring 2a. Because the fixing shaft 2b just fixes both ends of the ceramic ring 2a, it does not affect the gap, i.e. clearance, between the top and bottom blades 1A and 1B. Further, because the fixing shaft 2a is securely fastened to the ends of the ceramic ring 2a regardless of the thread-fastening position unlike the scissors in the related art, it does not become to loose and is useful to maintain the shearing capability of the scissors. Furthermore, the antibiotic treatment of the ceramic ring 2a is effective in use of cutting food. According to the scissors having rustproof blades of the invention, the ceramic ring used for the pivot has a rustproof characteristic and a considerably higher hardness, as compared with the metal of the blades or the fixing shaft, the blades are made of rustproof material, such as a Ti alloy or stainless steel, and the entire scissors is made of an rustproof material, so that the hardness of the ring and the scissors' durability can be increased. According to the scissors of the invention, the ceramic ring used for the pivot has high hardness, as compared with the metal of the blades or the fixing shaft and rustproof characteristic, so that it is not easily worn due to high hardness and also not corroded by acid, alkali, or salt from general usage. Further, because the blades are made of a rustproof Ti alloy or sintered ceramic and the ring used for the pivot is also made of a ceramic and the entire scissors are made of a rustproof material, the ring has high hardness and the durability of the scissors can be increased. Furthermore, the ceramic ring containing CuO prevents contamination from various bacteria, so that sanitation is improved and a pair of remarkably practical scissors is achieved. |