Patent Application
20060266789
1. Field of Invention
The present invention relates to a stapler and, more particularly, to a stapler capable of cutting staple legs.
2. Background of Invention
WO 03/057417 A1 discloses a STAPLER WITH BENDING ARMS WHICH CUT THE STAPLER LEGS AGAINST A PAD. The stapler includes two bending arms 40 and 41 and a cutter 49. The bending arm 40 is pivotally provided by means of a pin 42. The bending arm 40 includes a lever 45 on a side of the pin 42 and a bending surface 44 on the other side of the pin 42. The bending arm 41 is pivotally provided by means of a pin 43. The bending arm 41 includes a lever 48 on a side of the pin 43 and a bending surface 47 on the other side of the pin 43. The cutter 49 includes two cutting edges 50 and 51. The cutter 49 is located between the bending surfaces 44 and 47. As the levers 45 and 48 are pivoted, the bending surfaces 44 and 47 bend and press stapler legs 53 and 54 against the cutting edges 50 and 51. Thus, the staple legs 53 and 54 are bent and cut. Several problems have been encountered in using this conventional staple. The cutting edges 50 and 51 must be precisely located in the arched tracks of the travel of the ends of the bending surfaces 44 and 47 so that the shearing of the stapler legs 53 and 54 can occur between the cutting edges 50 and 51 and the bending surfaces 44 and 47. However, such precise location requires precise fabrication and assembly and inevitably incurs a high cost. Moreover, even the bending arms 40 and 41 and the cutter 49 are precisely fabricated and assembled at the beginning, the gaps between them will eventually become too large for adequate operation as they wear out after time of service. In that case, a user will have to use a lot of energy and spend a long time to staple a stack of paper with a staple.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.
According to the present invention, a stapler includes a base, a cover put movably on the base, a feeding device for feeding staples, and a bending and cutting device provided between the base and the cover for bending and cutting the legs of each staple. The cutting device includes a seat provided on the base and a housing attached to the cover. The seat includes two pushers of a first type formed thereon and a pusher of a second type formed thereon. A stationary cutting element is provided in the housing. Two movable cutting elements are provided movably in the housing and on the wedges so that they are moved towards the stationary cutting element in order to cut the legs of each staple as they are moved towards the seat together with the housing. A spring is put between the movable cutting elements in a tendency to push the movable cutting elements from the stationary cutting element. Two bending elements are provided movably and pivotally in the housing above the movable cutting elements so that they are pushed by means of the pusher in order to bend the legs of each staple after the stationary cutting element and the movable cutting elements cut the legs of each staple.
The primary advantage of the stapler according to the present invention is its low cost because it does not require high precision in assembly due to the movable cutting elements moved, instead of pivoted, towards the stationary cutting element.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description in conjunction with the attached drawings.
The present invention will be described through detailed illustration of the preferred embodiment referring to the drawings.
Referring to
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The first shell 21 includes a wall (not numbered) and a ceiling (not numbered) formed on the wall. Two slots 211 are defined in the wall of the first shell 21. In the wall of the first shell 21 are defined two slots 212 parallel to the slots 211. In the wall of the first shell 21 are defined two slots 213 parallel to the slots 212. In the wall of the first shell 21 is defined a recess 214 between the slots 212 and between the slots 211. In the wall of the first shell 21 are defined two recesses 215 on opposite sides of the recess 214. In the ceiling of the first shell 21 are defined two recesses 216 for receiving the legs 31.
The second shell 22 includes a wall (not numbered) and a ceiling (not numbered) formed on the wall. In the wall of the second shell 22 are defined two slots 221 corresponding to the slots 211. In the wall of the second shell 22 are defined two slots 222 parallel to the slots 221. The slots 222 are located corresponding to the slots 212. In the wall of the second shell 22 are defined two slots 223 parallel to the slots 222. The slots 223 are located corresponding to the slots 213. In the wall of the second shell 22 is defined a slot 224 corresponding to the recesses 215. In the ceiling of the second shell 22 is defined a slot 225 corresponding to the recesses 216.
Each movable cutting element 23 includes a first side, a second side opposite to the first side, a third side towards the third side of the other movable cutting element 23, and a fourth side opposite to the third side. Each movable cutting element 23 includes slides 231 and 232 on the first side, slides 231 and 232 on the second side, a stem 233 on the third side, a beam 238 on the third side above the stem 233, a shank 237 on the third side above the beam 238, a blade 235 on the shank 237, a recess 236 in the third side, and a slope 234 on the fourth side.
The movable cutting elements 23 are provided between the first shell 21 and the second shell 22. The slide 231 on the first side of each movable cutting element 23 is put in a slot 211. The slide 232 on the first side of each movable cutting element 23 is put in a slot 212. The slide 231 on the second side of each movable cutting element 23 is put in a slot 221. The slide 232 on the second side of each movable cutting element 23 is put in a slot 222.
The spring 27 is put between the movable cutting elements 23. The stem 233 of each movable cutting element 23 is fit in an end of the spring 27. The spring 27 tends to keep the movable cutting elements 23 from each other.
Each bending element 24 includes a hub 241, a groove 242 in the external side of the hub 241, a first arm 247 extended from the hub 241, a recess 244 in the tip of the first arm 247, a groove 245 in an upper side of the first arm 247, and a second arm 246 extended from the hub 241. An angle exists between the first 247 and the second arm 246. The second arm 246 includes a smooth arched profile.
A shaft 243 is inserted in the hub 241 of each bending element 24. Each shaft 243 includes an end inserted in a slot 213 and an opposite end inserted in a slot 223. The ends of the shafts 243 can slide in the slots 213 and 223. The hub 241 of each bending element 24 is put on the recess 236 of a movable cutting element 23. The groove 242 of each bending element 24 receives the shank 237 of a movable cutting element 23. Thus, smooth pivotal of the bending elements 24 on the movable cutting elements 23 about the shafts 243 is ensured even when they are moved together.
The stationary cutting element 25 includes two blocks 251 on a side, a passage 252 between the blocks 251, a ridge 253 on an opposite side, and a cutting face 254 on each of two other sides.
The stationary cutting element 25 is provided between movable cutting elements 23. Each cutting face 254 cooperates with a blade 235 in order to form a pair of shears. The stationary cutting element 25 is provided on the beams 238. The blocks 251 are put in the recesses 215. The ridge 253 is put in the slot 224.
The seat 26 includes two pairs of wedges 261 thereon, a slope 262 on each of the wedges 261 and a pusher 263 thereon. The seat 26 is made of a metal plate, and each wedge 261 is punched from the metal plate. Each wedge 261 is thin and alone cannot provide adequate contact with a movable cutting element 23. Hence, for contact with each movable cutting element 23, a pair of wedges 261 is used. However, each pair of wedges 261 can be replaced with an adequately thick wedge attached to or cast on the seat 26. The pusher 263 includes two chamfers (not numbered) at the tip.
The first shell 21, the second shell 22, the movable cutting elements 23, the spring 27, the bending elements 24, and the stationary cutting element 25 are provided on the seat 26. The slope 234 of each movable cutting element 23 is in contact with the slopes 262 of a pair of wedges 261. The second arms 246 of the bending elements 24 are located above the pusher 263. The pusher 263 is put in the recess 214.
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The stapler according to the present invention exhibits at least one advantage, i.e., its low cost because it does not require high precision in assembly due to the movable cutting elements 23 moved, instead of pivoted, towards the stationary cutting element 25.
The present invention has been described through the detailed description of the preferred embodiment thereof. Those skilled in the art can derive variations from the preferred embodiment without departing from the scope of the present invention. Therefore, the preferred embodiment shall not limit the scope of the present invention defined in the claims.
