US2997821A - Adapter for grinding planer knives - Google Patents

Description

Aug. 29, 1961 G. A. DIXON ET AL ADAPTER FOR GRINDING PLANER KNIVES 2 Sheets-Sheet 1 INVENTOR 5.

Aug. 29, 1961 e. A. DIXON ET AL 2,997,821

ADAPTER FOR GRINDING PLANER KNIVES Filed June 19, 1958 2 Sheets--Sheet 2 United States Patent 2,997,821 ADAPTER FOR GRINDING PLANER KNIVES George A. Dixon and Theodore F. Millick, Sr., both of Potlatch, Idaho Filed June 19, 1958, Ser. No. 743,199 1 Claim. (Cl. 51-218) The present invention relates to an adapter for grinding planer knives. In the planing mills where the surfaces of wood boards are finished smooth, there are many planer knives to be kept sharp. The necessity for accurate grinding is evident when one considers that in a set of knives for a particular planer head, all knives should be ground down alike. It is the purpose of our invention to provide an adapter which functions to hold a multiplicity of planer knives as a unit, in position so that they may all be ground and sharpened to the same finish.

Our invention is applicable to different lengths of knives. For short knives a single adapter may be suflicient, While for very long knives, a plurality of adapters are used as a means to hold a single set of knives.

The nature and advantages of our invention will appear more fully from the following description and the accompanying drawings. It should be understood, however, that the drawings and description are illustrations of the preferred form of the invention and that minor modifications may be made within the scope of the invention as defined in the claims.

In the drawings:

FIGURE 1 is a somewhat diagrammatic, fragmentary, perspective view, illustrating how the adapter holds a set of planer knives on a work support so they may be sharpened by a grinding wheel;

FIGURE 2 is a face view of a work support having three adapters supporting a set of planer knives; and

FIGURE 3 is a sectional view taken on the line 33 of FIGURE 2.

Referring now to FIGURE 1, our invention is shown in use with a work support which is a magnetic chuck which holds the adapters 11 and knives 12 carried thereby by magnetic attraction. The chuck 10 can be turned on its axis 13 to bring the chuck face horizontal for placing the adapters thereon, and then returned to the position shown, for engaging the knives with a grinder 14. The chuck 10 and grinder 14 are shown diagrammatically, since they are known commercial devices. Our invention is embodied in the adapters 11.

FIGURES 2 and 3 illustrate the construction of the adapter 11. It comprises a steel base 15 which is adapted to be secured to the work support or chuck 10 either by magnetic attraction, or by other suitable means. The base 15 has a toe portion 16 which is threaded to receive bolts 17 that hold a bevelled clamp 18. Extending across the top of the base '15 are parallel inclined ledges 19 which are offset from each other a distance equal to the thickness of one of the knives 12. The angle that each ledge 19 makes with respect to the plane of the chuck engaging face of the base 15 is about 31 degrees. We have found that this gives a good angle to the cutting face of the knife 12. The offset provides an abutment 20 at right angles to each ledge 19 for the back edge of the knife 12 to engage.

At the end opposite the toe portion 16, the base 15 has a wedge shaped heel portion 21, the top surface of which is parallel to the ledges 19. This wedge shaped heel portion 21 is threaded to receive bolts 22 which clamp a series of plates 23 against the inclined face 24 of the heel portion 21. The face 24 is in a plane perpendicular to the ledges 19 and the top surface of the heel portion 2,997,821 Fatented Aug. 29, 1961 21. The parts 21 23 inclusive, provide a support for the surface of the first knife 12, which support can be made longer or shorter, by changing the number of plates 23 used, to give proper backing for the knives while they are being sharpened by grinding. As a set of knives are used and sharpened repeatedly, they become narrower from front to back, so that, in grinding them, the outermost plates 23 have to be removed and the bolts 22 moved down to clear the grinder.

The clamp 18 is bevelled on its knife engaging face 18a at such an angle that the tip 18b of the bevelled face 18a will engage the knives first as the clamp is drawn down. This provides a secure clamping of the knives against each other to keep all of them in the proper position. By moving the group of knives 12 past a grinder 14, all of the cutting edges of the knives will be ground at the same angle and the knives will be of the same width.

The adapter 11 is made to take a multiplicity of knives 12. The number of ledges shown is sufficient to receive 14 knives. Twelve knives are shown in place in FIG- URE 3. If the number of knives to be sharpened is much less than 12, then a longer clamp 18 is used. The width of the knives determines the number of plates 23 to be used to back up or support the knives close to the sharpened edge. The length of blades used determines the number of adapters 11 that will be used to hold the knives on the chuck 10. FIGURE 2 shows three adapters. This is enough for knives of somewhat greater length. Two adapters will hold knives of shorter length.

It is believed to be clear from the foregoing description that we have provided an adapter which enables one to mount a multiplicity of planer knives on a chuck and sharpen them together so that they are all of the same width. They are easily attached to the adapters and can be removed together. By the use of these adapters, the knives of the planers can be kept sharp and uniform as they are worn down.

Having described our invention, we claim:

An adapter for grinding planer knives comprising an integral elongated base having a lower face for resting against a work support and a top face having in the central portion of the base between the ends thereof a series of parallel inclined ledges of equal width equidistant from the lower face, the planes of said ledges being spaced apart an amount equal to the thickness of the knives to be ground, abutments at the edges of the ledges to receive the back edges of knives laid on the ledges, a flat toe portion at one end of the base, an inclined heel portion at the other end of the base, the top surface of which is an extension of the end ledge, the heel portion including separable plates bolted to the base forming extensions of said top surface of the heel portion, a clamp plate overlying the toe portion and having a bevelled face overlying the adjacent ledges, the angle of the bevelled face with respect to the lower face of the clamp plate over the toe portion being less than the angle of the ledges with respect to the lower face of the base so the tip of the clamp plate engages knives on the ledges while the lower face of the clamp plate is inclined to the toe portion, and bolts extending through the clamp plate into the toe portion for holding the clamp in place.

References Cited in the file of this patent UNITED STATES PATENTS 506,401 Hill Oct. 10, 1893 1,867,623 Gouldbourn et al. July 19, 1932 2,056,491 Stimpson Oct. 6, 1936 2,242,887 Holdgate et al. May 20, 1941 2,371,515 Gorman Mar. 13, 1945 2,865,140 Shumway Dec. 23, 1958

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