1. Field of the Invention
The present invention relates to an apparatus for unrolling and sharpening a cutting edge on a blade that has its edges rolled or dulled. More specifically, the invention is directed toward improvements including top guide rails and the rear spring caps in such an apparatus. The invention includes improvements to the structure of the slot at the opening, including angled guide rails, and also, the resilient springs are more versatile and can be used in both flanges, each rear spring cap is only properly insertable in one side of the base due to their shape, and the pin rods and their relation to the base have been improved.
From time to time it becomes necessary to straighten, realign and sharpen the microscopic edge of a cutting tool such as a knife. During use, the edge of a blade becomes rolled or turned from direct contact with hard objects. It is important to maintain a uniform pressure and a proper even edge angle when sharpening a cutting edge. Previous sharpening devices have involved complex implements that commonly remove material from the cutting edge. Additionally, many of the previous devices are designed for use either only by a right-handed or left-handed person while sharpening one side of the edge at a time, not both. The present invention relates to a sharpener having a substantially enclosed versatile biasing assembly that resists contamination during use and provides for outstanding cleaning.
2. Description of the Prior Art
U.S. Pat. No. 5,478,272 owned by applicant herein describes apparatus for sharpening a cutting edge on a blade. The invention disclosed herein addresses specific improvements to that
U.S. Pat. No. 5,478,272 owned by applicant herein describes apparatus for sharpening a cutting edge on a blade. The invention disclosed herein addresses specific improvements to that apparatus. Although that apparatus successfully sharpens blades, the top portion could become worn through careless contact by the blade to be sharpened. Also, in replacing worn parts, the sharpening members could be installed backwards, and the stop members were difficult to remove because they did not pass through the entire base.
Earlier devices for sharpening blades fall into three broad categories: (a) devices having sharpening elements in permanent fixed relationship such as that disclosed in U.S. Pat. Nos. 578,440; 1,851,520; 1,909,743; 2,767,530 and 5,163,251; (b) devices having sharpening elements in movable relationship to each other with fully exposed biasing assemblies such as that disclosed in U.S. Pat. No. 4,934,110; and (c) devices having sharpening elements in movable relationship to each other with biasing assemblies not shielded from debris such as that disclosed in U.S. Pat. Nos. 1,041,631; 1,570,083; 2,124,646; 2,885,836; 4,550,632; and 4,624,079 as well as Patent Nos. GB 293,785 and GB 517,242.
There are problems and limitations with all of these earlier devices. Devices having sharpening elements in fixed relationship to each other are relatively inefficient, needing considerably more resistance when passing a blade between the elements in order to sharpen the blade and may not provide optimal sharpening of the blade. These arrangements often remove perceptible metal fragments from the blade, which shortens the useful blade life and is undesirable for contamination reasons.
In movable element arrangements, exposed biasing means, such as counterweights, lever arms, springs and the like, are prone to collect food particles and other debris during use. These sharpening devices are often used in food processing plants where the blades to be sharpened are full of meat particles. Where the spring is not shielded from debris that may accumulate during use, this condition can cause related problems of contamination and disease.
In certain food industries, governmental authorities regulate and inspect the processing of food for sale to consumers. While many sharpening devices produce a sharp blade, these prior devices have disadvantages of exposed parts or configurations that collect debris and contribute to the problems of contamination and disease. Additionally, cleaning the exposed parts of known devices is costly as these require specific attention to the meshed windings of springs and counterweights and the like. Cleaning may require disassembly of the housing in order to clean the apparatus and remove the debris. Sometimes when an operator is using prior art devices, the operator may be of the misconception, in not seeing the debris that is collecting, that all is well and the apparatus does not need cleaning, which in fact is not the case. Thus, there is a need for a blade sharpening apparatus of the present invention that eliminates operator error due to unseen contamination, reduces cleaning and maintenance costs, and eliminates contamination thereof.
Accordingly, it would be desirable to provide an improved blade sharpener. It has therefore been found beneficial to produce a blade sharpener with top guide rails at the upper end of the slot opening, springs that are more versatile and can be used in both flanges, improved rear spring caps that are only properly insertable due to their shape, and improved stop members that completely pass through the base.
The present blade sharpening apparatus includes a base member having a front face and a rear face. The base member has a slot adapted to receive and guide a blade to be sharpened. It is a primary objective of the present invention to enhance the durability of the base and the slot opening with top guide rails so a blade approaching the slot cannot cut into the plastic or other material of the base member.
The base member also has first and second apertures, one disposed on either side of the slot. Associated within the apertures are disposed a pair of resilient biasing members, such as springs, with each of the biasing members being substantially entirely enclosed within the base member. A first sharpening member is connected through a rotatable post to one of the resilient biasing members and is rotatable about a central axis of the first aperture with a first stop member adapted to limit the rotational movement of the first sharpening member in one direction. A second sharpening member is connected through a rotatable post to the second resilient biasing member and is rotatable about a central axis of the second aperture having a second stop member adapted to limit the rotational movement of the second sharpening member in one direction. The resilient biasing members are oriented so as to urge the respective sharpening members to a first position in which each of the sharpening members lies across a plane passing through the slot. In a preferred embodiment, the present invention may include two oppositely shaped rear spring caps that can only be installed in one position each for proper alignment of the rotatable posts and the sharpening members. The caps are marked with an indicium that corresponds to an indicium on the base, and if the spring caps are put into the wrong side, it is impossible to assemble the blade sharpener because the flanges will not fit into the base.
The sharpening members when in the first position define a V-shaped intersection overlying the slot. The first and second resilient biasing members are further operative to allow rotation of the respective sharpening members from the first position to a second position as the blade passes from one end of the slot toward the other. The resilient biasing members are enclosed within the base member and protected from debris and contaminants. The biasing members preferably use the same type of resilient biasing member (spring) on each side. The present invention provides improved features, make parts easier to remove and assemble, including stop members with a shoulder, which pass completely through an aperture in the base.
The above mentioned and other features of this invention and the manner of obtaining them will become more apparent, and the invention itself will be best understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings in which:
In the Figures, like reference numerals indicate the same elements throughout. Referring to
The base member 12 is provided with stop members 34, 36 and 38, preferably pins with knobs on the distal ends, which are configured to control and limit the rotation of the sharpening members 34, 36 and 38 between a first “at rest” position, as illustrated by the solid lines in
The base member 12 is generally formed of a hard durable plastic, such as polypropylene, that is easily cleaned by water and/or a cleansing solution. The base member 12 can be formed of any desired shape.
Rotatable posts 44 and 46 extend outwardly from the front face 14 of the base member and are rotatable about a central axis of the apertures 20 and 22 respectively. Sharpening rods 30 and 32 are secured to post 46 for rotation therewith and sharpening rod 28 is secured to post 44. As best shown in
The blade sharpener 10 includes top guide rails 48 and 50 so as to allow a blade to be easily inserted at the upper portion of the slot 18. The guide rails 48 and 50 are preferably formed of metal and angled toward the entrance 19 of the slot 18 to guide a blade into the slot 18 without the blade contacting the base member 12. Alternately, the guide rails 48 and 50 can be offset with one higher than the other as shown in
The sharpening members 28, 30 and 32 are manufactured from suitable material to sharpen a blade, such as, 440 C stainless steel hardened to 59-60 Rockwell C Standard by heat treating or the like. The sharpening members 28, 30 and 32 are illustrated as curved in shape but can also be straight as shown in the embodiments of
The stop members 34, 36 and 38 can be manufactured from steel, plastic, or other suitable material as is known in the art to be durable and to withstand the rigors of use. The stop members 34, 36 and 38 may be pins that have a shoulder that will be flush when the pins are pressed into the base. Since the stop members go all the way though the base member 12, the stop members 34,36 and 38 can be more easily removed and reassembled if the stop members 34, 36 and 38 become worn out.
The biasing members 24 and 26 can be made from rotary coil torsion springs having two free ends. In a preferred embodiment, each torsion spring provides approximately 0.51-0.55 pound-inches of torque to the rotatable posts 44, 46 and the sharpening members 28, 30 and 32 respectively connected thereto. The torsion spring should preferably be selected to provide such biasing torque although other tensions and torque specifications are contemplated depending on the desired application. Other resilient biasing mechanisms capable of accomplishing the same result could be substituted for the torsion spring mechanism.
The base member 12 further includes mounting holes 64 so that the blade sharpening apparatus 10 can be secured to a work station, countertop, machine, assembly line or the like. Bolts can be inserted through mounting holes 64 and mounting surface, and then fastened with nuts and washers as appropriate. Alternately, the blade sharpener 10 can be mounted on the top of a work table or cutting board using grooves 65 in the bottom lip of base member 12.
The posts 44 and 46 can be formed from DELRIN plastic or other suitable material as will be apparent to one skilled in the art. The posts 44 and 46 both include a front cover portion 68 in the form of a skirt that overlies and seals the apertures 20 and 22 on the front face 14 of the base member 12. The front cover portion 68 is rotatably received in a recess 70 (
The caps 97 and 98 seal the apertures (i.e., 20 and 22) on the rear face 16 of the base member 12 similar to the rear cover portions 58 discussed below and illustrated in FIG. 6. The caps 97 and 98 include central bore 62 and a recess 63, which receives a stem 52. The term “rear cover portions” is meant to define caps 97 and 98. A screw 60 passes through the central bore 62 and is secured into the end of stem 52, thereby sealing the apertures 20 and 22 on the rear face 16 thereof and securing the rotatable posts 44, 46, 72 or 74 in place. In this manner, the posts are secured to the base member 12 and are able to rotate with their associated sharpening members.
As shown in
In operation, a blade with rolled edges is positioned at the top of slot 18 and passed downwardly to the bottom of the slot 18 through the sharpening members 28, 30 and 32. The blade is pulled straight down until the sharpening members 28, 30 and 32 contact stop member 36. Then with light pressure, the blade is drawn across the sharpening members 28, 30 and 32 until the tip of the blade clears the sharpening members 28, 30 and 32 and the sharpening members 28, 30 and 32 spring back to the stop members 34 and 38 respectively. This motion unrolls curled edges of the blade.
After the straightening procedure, the blade may also be sharpened. At the top of the slot 18, the handle or hilt end of the blade is positioned close to the front face 14, while the pointed end of the blade extends well beyond the rear face 16, depending on the length of the blade. The blade is ideally pulled about three-quarters of the way down the slot 18 through the sharpening members 28, 30 and 32 in one continuous motion. As the blade is drawn from the top of the slot 18 to the bottom, it is also drawn horizontally through the slot 18 so the entire length of the blade is sharpened from the hilt to the point. The sharpening members 28, 30 and 32 contact and sharpen the cutting edge of the blade. As the blade moves downwardly the sharpening members rotate and move downwardly with the blade against the torque of biasing members 24 and 26. The sharpening members 28, 30 and 32 rotate from the first position as shown in full lines in
Referring to
The base member 12 is provided with stop members 34, 36 and 38 to control and limit the rotation of the sharpening members 34, 36 and 38 between a first “at rest” position, as illustrated by the solid lines in
Rotatable posts 44 and 46 extend outwardly from the front face 14 of the base member and are rotatable about a central axis of the apertures 20 and 22 respectively. Sharpening rods 30 and 32 are secured to post 46 for rotation therewith and sharpening rod 28 is secured to post 44.
The blade sharpener 10 includes top guide rails 48 and 50 so as to allow a blade to be easily inserted at the upper portion of the slot 18. The guide rails 48 and 50 are preferably angled toward the slot 18 to guide a blade into the slot 18 without the blade contacting the base member 12. Preferably, the gap between guide rails 48 is slightly narrower than the slot 18.
As best shown in
The blade sharpening apparatus 10 further includes rear cover portions 58 for sealing the apertures 20 and 22 on the rear face of the base member 12.
The operation of the blade sharpening apparatus embodiment of
In operation, the biasing members of
Referring to
A pair of rotatable posts 92 are provided, with a post extending through each aperture 20B, 22B. Each post is threaded at both ends with a nut 93 secured over the post at the rear thereof, as illustrated in
The operation of the blade sharpening apparatus of
The above description of the invention is intended to be illustrative and not limiting. Although the preferred embodiment of the invention is illustrated and described in connection with a particular type of blade sharpening apparatus, it can be adapted for use with a variety of blade sharpening apparatus. Other embodiments and equivalent tools are envisioned within the scope of the invention. Various features of the invention have been particularly shown and described in connection with the illustrated embodiments of the invention, however, it must be understood that these particular embodiments merely illustrate and that the invention is to be given its fullest interpretation within the terms of the appended claims.
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Number | Date | Country | |
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20040097179 A1 | May 2004 | US |