Patent Publication Number: US-2010115776-A1

Title: Manual Can Opener Tool

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a hand-operated can opener of simple design, and which does not rely on cranks or gears. The invention is more particularly directed to a hand-held implement for opening a steel can or the like. The invention is especially concerned with a can opener device with a minimum of moving parts, which can be easily adjusted to the size of the can, and which can quickly cut and remove the lid, with either right-handed or left-handed operation, and without relying on the user having to manipulate a twist handle or crank. 
     Currently, portable hand-held can openers require a gripping device that clamps onto the rim of the can, and to move the can when a crank handle is rotated. A knife that is a part of the opener penetrates the can lid near the rim, and makes a circular cut through the rim when the can is rotated. 
     The openers of this type tend to be bulky and have moving parts, typically including a gear drive and a clamp to grasp the rim of he can. These items can wear and can fail. Moreover, some persons, including the elderly and those who experience joint pain, can find it difficult to work the crank handle or winder of the device, or to work the clamp portion. 
     Accordingly, there is a need for a simple can opener device that has a minimal number of moving parts, and which does not require the user to manipulate a winder or crank. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a can opener device of simple construction which overcomes the drawbacks of the prior art. 
     It is another object to provide a can opener that is simple to use and can open the lid of the can in either direction. 
     A further object is to provide a can opener device which is small and portable, and which can be easily used by any person. 
     According to one aspect of the invention, a manual can opener, for cutting through the can&#39;s metal lid is in the form of a tool having an elongated shaft with a proximal end, a distal end, and a profile with at least one non-circular portion adapted to serve as a keyway so that the shaft is blocked against rotation. A handle is mounted onto the proximal end of the shaft, and there is a piercing spear point at the distal end of the shaft. A generally triangular cutting knife is carried on the shaft and can slide along the shaft, so that its position along the shaft can be adjusted. The cutting knife, which is favorably a plate of steel, has a distal face and a proximal face, and a pair of side walls that are tapered from the distal face to the proximal face to form cutting edges. These side walls meet to form a vertex or point that is oriented down, i.e., towards the can lid. There is a shaped passage through the cutting knife, and the passage has a keyed profile that mates with the shaft. Thus, the shaft passes through the passage, and while the cutting knife can be slideably adjusted in position along the shaft, the knife is blocked from rotation about the shaft, and is held so that the vertex remains oriented at one predetermined side of the shaft. 
     Favorably, the cutting knife is in the form of a triangular steel member having a thickness of between 1 mm and 2 mm, preferably about ⅛ cm. 
     The shaft may have a square profile, hexagonal profile, or another polygonal profile, and the passage can have a matching square, hexagonal or other polygonal shape. 
     The spear point is favorably in the form of a flattened pointed spade member, and the distal end of the shaft can have an offset that joins the spade member and displaces it to the one predetermined side of the shaft, i.e., the same direction as the vertex of the cutter blade. 
     The method of manually opening a can may be carried out, using the above-described can opener tool, as follows: The user holds the handle end in his or her hand, and places the spear point of the can opener at a center point of the lid. Then the user pushes the opener against the can lid to pierce the lid at the center point. The position of the cutting knife along the shaft is adjusted, as needed, so that the point or vertex of the cutter blade will come down near the rim of the can. The user rotates the opener downward, using the spear point as a fulcrum, until the vertex of the cutting knife penetrates the can lid, rotating the opener about a vertical axis of the can to cut the can lid. 
     The above and other features and advantages of the can opener tool of this invention will become apparent from the ensuing description of a preferred embodiment, which is to be read in conjunction with the accompanying Drawing figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a perspective view of a can opener tool according to one embodiment of this invention. 
         FIG. 2A  shows the distal end of the shaft and piercing spear point thereof. 
         FIG. 2B  shows a central port of the shaft and cutting knife thereof. 
         FIG. 2C  is a plan view of the cutting knife taken at line  2 C- 2 C of  FIG. 2B . 
         FIG. 2D  is an edge-on view of the cutter knife taken at line  2 D- 2 D of  FIG. 2C . 
         FIG. 3  and  FIG. 4  are perspective views for explaining the operation of the can opener tool of this embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the Drawing,  FIG. 1  and  FIGS. 2A to 2D  illustrate the can opener tool  10  of an embodiment of this invention. 
     As shown in  FIG. 1 , the tool  10  has a handle  12 , which can be molded of a suitable durable plastic material. This handle is favorably about 11 cm long and about 2.5 cm wide, e.g., similar to a conventional screwdriver handle. An elongated steel shaft  14  has its proximal end embedded into the handle  12 , and the shaft projects out about 9 cm to 10 cm to a distal end. The shaft  14  in this embodiment is a square steel shaft, about ½ cm on a side. The shaft can have a different profile, e.g., hexagonal or even round with some non-circular keyway formed in it, if preferred. 
     A piercing head  16  is formed at the distal end of the shaft  14 . Here this head  16  is a flat, spade-like, i.e., generally triangular spearhead, with a pointed tip. There is an offset  18  at the end joining the piercing head  16  to the distal end of the shaft, and displacing the head to one predetermined side of the shaft  14 , i.e., below the lower side of the shaft in this illustration. 
     A cutter blade  20 , which is a generally triangular flat steel plate, is mounted on the shaft  14  and is free to slide along at least a portion of the shaft between the handle  12  and the piercing head  16 . As shown more specifically in  FIGS. 2C and 2D , the cutter blade has a point or apex  22 , also oriented in the direction that is downward in these views, below the lower side of the shaft  14 , i.e., the same direction as the offset  18 . There is a square opening  24  at or near the center of the cutter blade, forming a passage for the shaft  14  with a profile that matches the profile of the shaft. This allows the cutter blade  20  the freedom to slide along the shaft, but blocks it from rotating about the axis of the shaft. 
     The triangular cutter blade  20  has side walls  26  that are tapered from one side to the other, i.e., between the proximal and distal surfaces, so that they the side wall meets one of these, e.g., the proximal wall, at acute angle to form a sharp cutting edges  28 . The two side walls  26  angle toward another and meet at the lower point or vertex  22 . The cutter blade does not have to be a triangle but should have symmetry so that the vertex or point  22  can penetrate the can lid near the rim of the can, and so that the blade can cut in either direction. In this embodiment, the cutter blade is a triangular plate about 19 mm on a side, and has a thickness of about 1.2 mm. In other favorable embodiments, the cutter blade may have a thickness of between 1 and 2 mm. 
     The process for opening a steel can, e.g., a sealed container of a consumable food material, will now be described with reference to  FIGS. 3 and 4 . 
     The typical steel can  30  has a generally cylindrical side wall, and a lid  32  in the form of a disk of sheet steel, joined to the side wall at a rolled rim  34 . It should be noted that the method can be used with cans of oval or other non-circular profile, without much difficulty, but for purposes of simplicity this example shows a can  30  of round profile. 
     The user first picks up the opener tool  10  by the handle  12 , and places the spear point  16  at the center of the lid  32 , as shown in  FIG. 3 . Then, the user presses down, and the spear point  16  penetrates the lid  32  at the center. The user rotates the tool downward, using the spear point against the center hole formed in the lid as a fulcrum, and brings the handle down to the position shown in  FIG. 4 . The position of the cutter knife  20  along the shaft  14  is adjusted, as need be, so that the apex or point  22  of the cutter blade is on the can lid  32  adjacent the rim  34  of the can. Then the user presses down on the handle  12 , and by lever action penetrates the metal of the can lid  32  with the cutter knife  20 . Then the user pulls (or pushes) the handle  12 , and moves the tool  10  in a circle about the center of the can lid  32 , where the head  16  serves as a fulcrum. Here, the offset  18  on the shaft rests against the metal edge of the center hole in the lid. The user rotates the tool  10  around the can, in either direction, to form an arcuate cut  36  as seen in  FIG. 4 . Then the lid can be bent up, or removed, as desired. The tool  10  prevents the lid  32  from falling into the can  30 , so that any dust or other material on the top surface of the lid  32  is prevented from contaminating the can&#39;s contents. The lid can be lifted off the can with the tool, and the lid remains on the shaft  14  of the tool until it is pushed off. This means that the user does not need to grasp the can lid with his or her hand, and there is no risk of injury to the hand from the sharp cut edge of the can lid  32 . 
     As mentioned before, this embodiment is given as an example, and there are many possible variants of the can opener tool. The knife  20  can be of a different shape, and does not need to be strictly triangular. The shaft  14  shown here has a square profile, but in other embodiments, the shaft could have a different cross section, such as hexagonal or another polygon, so long as there is at least one non-circular portion that can serve as a keyway against rotation on the shaft. In this embodiment, the handle  12  is a molded plastic handle, but in other embodiments, the handle may be unitarily formed with the shaft  14 . The cutting knife  20  can have a two-part construction, instead of the single-piece construction shown here. The piercing head and offset can have other shapes, while still serving the same function. 
     While the invention has been described with reference to one embodiment, it should be recognized that the invention is not limited to that precise embodiment. Rather, many modifications and variations will be apparent to persons skilled in the art without departing from the scope and spirit of this invention, as defined in the appended claims