US2136260A - Knife for lumber-dressing machinery - Google Patents

Description

. Nov. 8, 1938. WALTMON 2,136,260

KNIFE FOR LUMBER DRESSING MACHINERY Filed Dec. 30. 1956 INVENTOR. .Z IOMA-S J MLr o/v.

ATTORNEYS.

BY Ma Patented Nov. 8, 1938 UNITED 's'm'rizs PATENT OFFICE KNIFE FOR LUMBER-DRESSING MACHINERY Thomas J. Waltmon, Portland, Oreg., assignor to The Ohio Knife Company, Cincinnati, Ohio, a

corporation of Ohio Application December 30, 1936,.Seiial No. 118,343

1 Claim.

configurations and surfaces; and the appended claims: isintended to relate to the invention broadly and without restriction to the. specific exemplary embodiment herein described.

The dressing of lumber such, by way of example as a 2 x 4, has usually been carried on in two operations, in each of which a pair of opposite faces of the piece are simultaneously dressed by cutter heads opposed to each other. In the usual vertically disposed cutter heads, the knives are fastened in a drum so as to lie at a large angle to the tangent of the drum surface.-

The drum is slotted to receive the knife and suitable clamping means for the knife are provided. The knives have a back which is corrugated to coact with a clamping element, and a face which is normally planar. Knives intended for making a straight out are normally beveled from'the face toward the back so that the face sideof the knife is the longest or deepest side. When the knives are intended to take a shaping or nonplanar cut, it has been the usual practice to groove or machine the back of the knife and then bevel the knife'in the opposite direction, namely, from the back toward the face; there being usually, a meeting bevel of lesser extent in the opposite direction. Therefore, in this form of knife the back face is the longest or deepest face. Such knives, however, cannot be mounted in the cutter heads as hereinabove described, for the reason that their angularity is wrong. They have to be employed in a cutter head in which the knives are mounted much more nearly tangentially since otherwise the knife edge would tend to scrape and tear the wood.

When eased edge lumber began to be important in the market, the only provision the art made was the provision of knives of the shaping variety hereinabovediscussed. These knives cannot be employed in the ordinary cutter heads. New heads ofa different style had to be purchased at considerable expense. This made it impossible for the smaller mills in many instances to make eased edge lumber, where new cutter heads could not be afforded.

It is an object of my invention to provide a type of knife suitable for making a non-planar cut but operable in the ordinary cutter head and interchangeable with the ordinary knives.

It is an object of my invention to provide. a

knife structure capable of adjustment so as to provide on a given face of the lumber rounded edges properly spaced apart.

It is an object of my invention to provide a type of knife for the purpose described which may be sharpened if required without impairing 1 the ability of the knife to make the shaping cut.

It is an object of my invention to provide a knife which will have suitable clearance means for the removal of chips.

These and other objects of my invention, which 1.5:

will be set forth hereinafter or will be apparent to oneupon reading these specifications, Iaccomplish by that certain construction and arrangement of parts of which I shall now describe the aforesaid exemplary embodiment. 20

Reference is now made to the drawing, wherein,

Fig. 1 is a view in perspective showing a piece of lumber being dressed on its opposite sides by a pair of cutter heads. The table of the planer 5 and its appurtenances have not been shown since they are known in the art and do not constitute limitations upon my invention.

Fig.2 shows a blank in perspective from which a knife of my improved type may be produced. 30

Fig. 3 is a perspective View of one of the completed knives, and shows also the filler member.

Fig. 4 is a partial plan View of one of my knives from the face side.

Briefly in the practice of my invention, I pro- 5 vide a knife having a usual corrugated back, and a face side, a portion of which is cut away so as to lie at a lower plane. When this knife is beveled from the face toward the back to give a cutting edge, the cutting edge is characterized by 4 a rounded shoulder as will be more definitely hereinafter described. The raised portion of the face is tapered from the cutting edge of the knife toward the bottom to give a good chip clearance for cutting. There is a filler plate employed with 45 my knife to coact with the clamping means and to fill up the cut-away portion of the face of the knife over the area of engagement of the clamping means with the knife. My knives may be made in rights and lefts and are capable of 0 use in the ordinary way in the ordinary cutter head as distinguished from specially made cutter heads. Being made in rights and lofts, each knife operates to plane the face of a piece of lumber and to produce one eased edge adjacent 5 the face. The next knife also planes the face and produces the other eased edge. The knives may be adjusted in the cutter head by moving alternate knives in opposite directions so as to gauge the proper distance apart of the eased edges.

I have shown in Fig. l a piece of lumber I, being operated upon by two cutter heads 2 and 3. These cutter heads are generally circular in cross section as shown and are removably fixed by suitable means 4 and 5, as well known in the art, to the driving shafts 6 and I. The cutter heads are slotted as at 8 to receive the knives and a side of the slot is corrugated to engage with the corrugations on the back of the knife. A clamping block is shown at 9 operating to hold the knife against the corrugated face of the slot, and controlled by suitable set screws or the like In and II.

The knife is more clearly shown in Figs. 2, 3 and 4. In Fig. 2 a knife blank I2 is shown as having a substantially rectangular body. The back face of the knife is corrugated as shown at 13. The front face of the knife has its larger portion M machined or ground down so as to lie in a lower plane than a triangularly raised face portion l5. The knife blank is rounded as at 16 between the two planes l4 and IS. The portion! 5 tapers as shown, from the cutting edge of the knifetoward the bottom thereof, to give a sufficient clearance for chips. The knife is completed by being ground off on a slanting plane I! from the face toward the back; and. when so ground, the knife will have a cutting edge as shown in'Fig. 4 of which the larger part lies in a line I 8 at one level and a smaller portion in a line [9 at a higher level, there being a rounded portion 20 between the two plane portions.

The profile of the cutting edge of the knife as shown in Fig. 4, clearly indicates the type of cut it will make. The portion 20, of course, makes the eased edge.

I provide, in connection with my knife as shown in Fig. 3, a filler member 2| to fill out the difference between the planes l4 and I5 of the knife. This is a thin, generally rectangular piece of metal, the edge 22 of which, however, is slanted to follow the slant of the rounded portion IQ of the knife and is similarly rounded as at 23. The thickness of the member 2| is sufficient, when the member is laid on the face M, to make the top edge of it co-planar with the face portion l5. In this way, the clamping member 9 is given an adequate purchase on the knife.

As has been indicated, the knives are made and sold in rights and lefts, which are reverse counterparts of each other. The knives are placed in the cutter heads in an arrangement consisting of alternate rights and lefts as illustrated in Fig. 1. It will be seen in this figure that adjustment may readily be made for the dressing of lumber of different widths. Thus the knife A may be moved downwardly as indicated by the dotted lines, while the knife B, which is a reverse counterpart of the knife A may be moved upwardly as indicated by the dotted lines, thus making provision for the dressing of wider lumber.

The knives may be ground or sharpened in the ordinary Way and will retain their ability to dress eased edge lumber. By reason of the slanting disposition of the curved portion N5 of the knife, it will be clear that as the knife is sharpened away, the rounded cutting edge 20 will tend to move somewhat outwardly toward one side of the knife. This, however, is compensated for by adjustment of the knives in the manner last hereinabove described.

Modifications may be made in my invention without departing from the spirit of it; and in particular, as will be apparent, knives of the type herein described and claimed may be used for cutting other types of configurations than the one herein expressly set forth.

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

In combination a knife of generally rectangular form having a corrugated back side and a front side with portions lying at different effective levels, said knife being beveled from the front side toward the back side so that the front side is the longer of the two sides, so that the cutting edge of said knife has a configuration other than that of a continuous straight line, by reason of said different effective levels, and a filler block so shaped that when laid against the front face of said knife it will present an outer surface flush with the highest level of said front face.

THOMAS J. WALTMON.

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