US2475371A - Sharpener for blades - Google Patents

Description

July 5, 1949. P. D. BROWN 2,475,371

SHARPENER FOR BLADES Filed Feb. 19, 1949 Fig. 7

Pau/ 0 BMW/7 IN VENTOR.

BY Wm ATTORNEY.

Patented July 5, 1949 Mrs!) 'rrn'r rose-ice 1 This invention relates to sharpeners' for. :blades of various kinds including: razor blades as well as knives and other cutters and it has for its principal object. the provision -of"a =compact and simple device capable of producing cuttingedges I having diiferentdegreesof angularity as desired.

A second object is to avoid thecreatioh of feather edges, a previous defect in ballatypelsharpeners.

Fmother object is to clamp the-Lballs or'bosses firmly: for: th sharpening operation" while-permitting them to be readily cleaned. Other detail objects will become apparent as the description proceeds. While the invention may take various forms, the preferred form here illustrated is a handy pocket type convenient for either the home or traveling.

Referring now to the drawings forming part of this specification,

Fig. 1 is a plan view of the device, showing how it is applicable to blades of different cutting angularity.

Fig. 2 is an end view of the device.

Fig. 3 is a side view showing the sharpening bosses clamped in position for sharpening.

Fig. 4 is a side view showing the sharpening bosses released for cleaning.

Fig. 5 is a detail side view of one sharpening boss, showing its flattened dome and minimum radius of sharpening curvature.

Fig. 6 is a side or front view of the same boss illustrated in Fig. 5, showing its oval or ovate configuration, which provides sharpening arcs of minimum radius of curvature on the line A-A and less curved arcs having greater radii of curvature in other positions such as along the line Bl3.

Fig. 7 is a greatly enlarged view of the faces of the sharpening bosses in conjunction with the edge of a razor blade if held in the position 8 of Fig. l-the curvature corresponding to the plane A--A of Fig. 6.

Fig. 8 is a similarly enlarged view of the faces of the sharpening bosses in conjunction with the edge of a razor blade when held in the position 9 of Fig. 1-the curvature then corresponding to the plane B-B of Fig. 6.

Similar reference numerals refer to similar parts thruout the various views, except that the reference numeral 8 applies to a razor blade with one type of edge and the reference numeral 9 applies to another razor blade having a more acute type of edge.

Referring now to Fig. 1, Fig. 2 and Fig. 3, the sharpener consists of a handle or body 1 against which normally abuts a slidable ring 2 when the sharpener is in usei When the sharpener is 'being cleanedtherihg. 2 is-slid down against-the fixed. collar 3 which is securely attached tc-"the rigidjaws 3, shown in side view in 3 and Fig. 4. The jaws 'i-are preferably made-integral with the handle l, as shown Fig. l,-and-are kept from springing apart both by their rigidity and by the encircling collar or band 3.

Attached to the slidable' collar 2 are a pair of spring leaves? having .oval o-r ovate sharpening bosses 6 with flat contacting surfaces -l which meet when the bosses 6 are clampedtogether in sharpening position; The bosses .fihave and their shorter or minor axes longitudina1 of the blades 5, as along the line AA of Fig. 6. Consequently the curvature of the sharpening bosses 8 is more pronounced on the minor axis line A-A than elsewhere.

Fig. '7 shows on an enlarged scale this more pronounced curvature as would be found on the line A-A, with the flats l in contact and the sharpening surfaces 6-6 curving away quite abruptly. When a blade has its edge rubbing on this region of abrupt curvature, as shown in Fig. 1 at 8, the sharpenin effect is to give an edge with an angle such as 8 in Fig. '7.

On the other hand, if a blade 9 is sharpened by motion along an oblique angle such as shown in Fig. 1, it naturally rubs on portions of the bosses 6 where the radius of curvature is greater and the divergence of the bosses less pronounced. This then produces a more acute angle as shown at 9 in Fig. 8. Various other angles may be obtained at intermediate points.

In any event, the fiat surfaces 'I-laeing the flattened tops of the domes 6- prevent the curves of the domes 6 from meeting tangentially as has been common in the past where two balls met at a point to form a sharpener. In the present device, the flat surfaces insure a definite angle at the cutting edge, as distinguished from the indefinite or feather edge produced when two arcs meet at a mere point, tangentially. Theoretically when two curves meet at a point they approach or reach parallelism and so tend to produce an edge of infinit thinness, which while theoretically sharp, is in practice a poor cutting edge, since it will not stand up. The fiat surfaces '5 as shown in Fig. 7 and Fig. 8 overcome such a defect.

The blades 5 may be attached to a pin ID by being bent in the form of an eye ll-the pin it! with its blades 5 sliding in the slot 12 between the jaws 4 as shown in Fig. 4. When the slide 2 is at the right as shown in Fig. 4 the blades 5 are less constrained and spring slightly apart so that the surfaces between the bosses 6 can be cleaned. When in use for sharpening, the slide 2 is at the left as shown in Fig. 1 and Fig. 3, as the bosses 6 are then clamped together as previ ously described.

It will be seen from the foregoing that the device readily provides for diiferent types of sharpening of more or less angularity, and in any event the result is always an edge of sufllcient angularity to insure a strong cutting edge. This therefore gives an improved result unobtainable in previous ball-type sharpeners. The device may be easily and inexpensively manufactured and produced in very simple forms.

While I have in the foregoing described a certain specific embodiment of the invention, it will be understood that it is merely by way of example to illustrate the principle of the device, which is not necessarily limited to the particular form shown, but is susceptible to various modifications and adaptations in different installations as will be apparent to those skilled in the art, without departing from the scope of the invention as stated in the following claims.

I claim:

1. In a sharpener, the combination of a pair of rigid jaws, a pair of flexible leaves slidable in said jaws to various degrees of divergence, a pair of sharpening bosses on said leaves, said bosses having various radii of curvature on divergent sharpening faces and also having flat surfaces where the bosses come in contact with each other,

so that different angles of sharpness may be produced by rubbing blades on difierent sides of the bosses, the flat surfaces insuring an appreciable angularity.

2. In a sharpener, the combination of a pair of rigid jaws, a collar slidable on said jaws, a pair of leaves attached to said collar and located between the jaws, oval sharpening bosses on said leaves, said bosses having flattened faces where they come in contact with each other, the bosses being clamped together by movement of the slidable collar, whereby different angles of sharpness may be produced by rubbing blades on different portions of the ovals.

3. In a sharpener, the combination of a pair of rigid jaws, slidable extensions between said jaws, sharpening bosses on said extensions, said bosses having sharpening surfaces with various degrees of curvature so that different angles may be produced by rubbing blades to be sharpened on different portions of them, said surfaces meeting at angles greater than tangency.

4. In a sharpener, the combination of a pair of flattened dome shaped sharpening bosses having sharpening surfaces of various degrees of curvature so that different angles may be produced by rubbing blades to be sharpened on different portions of the dome shaped bosses, and clamping means for holding the flattened portions of said dome shaped bosses together.

PAUL D. BROWN.

No references cited.

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