US2147079A

US2147079A - Apparatus for grinding curved blades

Info

Publication number: US2147079A
Application number: US187739A
Authority: US
Inventors: Harlin W Barnard
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-01-29
Filing date: 1938-01-29
Publication date: 1939-02-14
Anticipated expiration: 1956-02-14

Description

Feb. 14,1939. -H W BARNARD 1 2,147,079

APPARATUS FOR GRINDING CURVED BLADES Filed Jan. 29, 1938 Patented Feb; 14, 1939 UNITED STATES PATENT OFFICE 2,147,079 APPARATUS FOR. GRINDING CURVED BLADES Harlin W. Barnard, Olean, N. Y. 7 Application January 29, 1938, Serial No. 187,739

3Claims. (01. 51-100) This invention relates to means for grinding cutting blades and its principabobiect is to pro-- vide means of uniformally beveling the surface of the blade terminating in the cutting edge, of 5 blades having compound edge curvature, that is to say, blades having difierent portions of their edges curved on different centers of curvature.

The primary object of this invention is to provide means for grinding a knife blade with a bevel edge wherein the line of bevel will be substantially concentric with the varying curvature of the cutting edge by the use of a specially designed blade holder adapted to be moved in fixed relation to the grinding means and bringing all points 15 of the edge of a compound curved blade progressively into bevel forming positions, in relation to the grinding means whereby a bladehaving an edge formed in two or more curves, a curve of short radius near the blade point, merging into *a curve, or curves of long radii in the body of the blade, will be provided. with a uniform bevel throughout its cutting edge.

The apparatus herein shown comprises as its principal units, a blade holder with a controlling factor for accurately determining the path and position of the blade holder at various points in its movement with relation to the grinding and sharpening means.

These and other features of the invention will be more clearly understood from the following description thereof, together with the accompanying drawing, in which- Fig. 1 is a view in side elevation of the blade holder assembled with a knife blade positioned therein.

' Fig. 2 is a plan view of the outline of a blade blank adapted to be positioned in the blade holder.

Fig. 3 is a plan view of one of the pair of side plates forming the blade holder.

Fig. 41s a plan view of the bottom element of the blade holder adapted to be positioned intermediate of the side plates in theblade holder I Y assembly.

Fi 5 shows a cross section view of the blade holder and blade shown in Fig. 1 on the line 5-5.

Fig. 6 shows a cross section view of the blade holder and blade on the line 6-8. s

Fig. 7 is a view in-side elevation of the blade holder with a blade positioned therein preparatory to the grinding operation.

Fig. 8 is an end view of the companion grinding disk with the blade holder with blade therein positioned for the grinding operation.

In the drawing Figs. 1 to 4 inclusive, are shown 05 the component parts of the blade holder assembly 5, wherein l0 designates the bottom part of the blade holder, ll designates one of the companion side plates adapted to be riveted together with the bottom element l0 interposed therebetween to form a troughinto which the blade is 5 positioned.

The bottom element I0 has a definitely shaped outline on both edges, the object of which will be more fully explained.

As shown in Fig. 2 the knife blade blank [2 10 is formed with a contour at its back edge providing shoulders formed at I and 2. This contour conforms to the shape of the blade contacting edge of the bottom element Ill shown in Fig. 4. As the back of the blade blank l2 rests upon the bottom element ill, the shoulders I and Zwill maintain the blade blank l2 against lateral movement within the blade holder 5 by the shoulders I and 2 registering in the

depressions

3 and 4 of the bottom element l0.

Further resistance to lateral movement of the blade 12 is provided by the extension l3 of the member l0 which engages the end of the tang portion of the blade .To afford suitable grinding means there is provided, as shown in Fig. 8, a pair of companion grinding disks l5 and I5 formed of any suitable abrasive medium, mounted upon suitable arbors, rotatively mounted in bearings well known in the art (not shown) the arbor of the one companion disk l5 being held in a fixed position, and the arbor of the other companion disk I 5, being adapted to move in a horizontal plane toward and away from the companion disk l5 mounted on the fixed positioned arbor, by means well known Y in the art (not shown).

Positioned in a vertical plane on a line between the peripheries of the companion disks l5 and I5 is an adjustable standard or post id, upon which the back of the knife blade holder I0 is adapted to contact in its movement duringthe grinding operation.

The form of the blade holder element l0 forms an important part of this invention, as will be appreciated as the grinding operation is more fully described as follows:

With the blade blank l2, positioned inthe blade holder 5, as shown in Fig. 1 the blade holder with the blade therein is placed in position between the grinding disks l5 and IS with the back member In of the blade holder resting upon the support H as shown in Figs. 7 and 8.

With the edge of theblade blank l2 interposed between the companion disks l5 and I5 in a grinding contact therewith, the .blade holder element l resting upon the supportingelement M, which so guides the topedge of the blade blank 12, with respect to its relation with the grinding disks that the line of bevel shown as It in Fig.1 will be substantially parallel with the outline of the bottom edge of element It! contacting the top of the supporting element ll.

It will be obvious that other forms of curved surface elements III may be provided to form other contours of the line of bevel as well as the contour of the cutting edge of blades of other shapes.

In the movement of the *blade holder as shown in Fig. 7 from right to left, as the element l0 moves on top of the supporting element It, the declining curve formed in the terminal of the elem nt l0 willcause the. blade holder 5 to change ts path on movement to apply the cutting edge of the knife blade to the abrasive means along a line of curvature determined by the arc of the curve formed in the terminal of the element "I. It will be obvious from the foregoing description of its operation, that with my improved apparatus, knife blades having curved cutting edges may be readily ground by inexperienced operators to produce a line of bevel extending back from the cutting edge, a predetermined distance and concentric with the cutting edge.

It will be obvious to those skilled in the art, that a uniform bevelwill be formed on both sides of the blade in the one operation.

Having thus described my invention, what I claim as new and desire to secure by Letters Patcut is: v

1. In a grinder for knives having compound 2,147,079 '5, is moved horizontally with the blade holder curved cutting edges, the combination with a pair of grinding wheels, a support intermediate thereof, a portable blade holder associated with said support and adapted for lateral movement thereon with its support contacting surface formed in a compound curve whereby successive portions of the curved cutting edge of the knife may be selectively applied to the grinding wheels during a lateral movement of the blade holder.

2. In a grinding device for knives having compound curved cutting edges, the combination with a frame of a. pair of grinding wheels mounted for adjustable relation therein, a support intermediate of said wheels, a portable blade holder associated with said support and adapted for lat eral movement thereon having its support contacting. surface formed in a compound curve whereby in its lateral movement, successive portions of the compound curved cutting edge of the knife may be selectively applied to the grinding wheels.

3. In a grinder for knives having compound cutting edges, the combination with a frame of a pair of grinding wheels mounted in said frame to be moved in adjustable relation to each other, and adjustable support intermediate of said wheels, 9. portable knife blade holder associated with said support and adapted for lateral movement thereon formed with its contacting 'surface in a compound curve whereby in its lateral movement, successive portions of the compound curved cutting edge of the knife may be selec tlvely applied to .both grinding wheels during the lateral movement of the blade holder.

. HARLIN W. BARNARD