US1685373A - Heinrich ohagen - Google Patents

Description

Sept. 25, 1928. 1,685,373

H. OHAGEN MILLING CUTTER FOR- CUTTING SHARPLY POINTED ANGULAR INCISIONS INTO WOOD Filed A ril 14, 1927 Patented Sept. 25, 1928.

UNITED STATES PATENT OFFICE.

HEINRICH OHAGEN, oF BREsLAU, GERMANY.

MILLING- CUTTER FOR CUTTING SHARPLY-POINTED ANGULAR INCISIONS INTO WOOD.

Application filed April 14, 1927, Serial No. 183,740, and in Germany April 23, 1926.

This invention relates to a milling cutter for making in wood sharply pointed angular incisions. It has been found that incisions in wood in the shape of an acute angle cannot be produced with the aid of a milling-cutter, the

= cutter cuts the incision substantially to about half its depth, the middle-cutter cutting then to about of the depth and the last cutter cutting then the fine point of the incision and giving to the incision the final sharp shape. The milling-cutters are so arranged that they either move the one directly behind the other, or the milling-cutters of different size are arranged on a common disk. When this working method is applied the individual cutters are submitted to such little stress, that no getting hot nor burning of the knives occurs.

in the acccnianying drawing:

Fig. 1 shows in cross section a. piece of wood with an acute-angled incision.

Fig. 2 shows in plan view the piece of wood and the arrangement of the milling cutters for producing the incision, three cutters having knives of different length and thickness 5 running the one behind the other.

Figs. 9, and 11 show each another form of construction of the milling-cutter in which the roughing knives and the finishing knives are united in one single cutter, the longer finishing knives being oscillatably mounted in U the cutter-disk.

As shown in Fig. 2 the three cutters A, B and C are rotatably mounted in the bearings of a common frame D, the cutter A being driven by the belt-pulley 1, the cutter B by the belt-pulley 2 and the cutter C by the belt-pul The knives 6 of the cutter A are shorter than the knives 7 of the cutter B and these are again shorter than the knife 8 of the cutter C. The knives 6 reach to about one half of the depth of the incision to be cut, the knives 7 to about of the depth of the incision, while the knives 8 serve to cut the fine point of the incision.

A special. characteristic feature of the invention consists in the construction of the knives 6,7 and 8. The side-faces of the roughing knives 6 and 7 have sharp edged grooves 9, so that these sidefaccs exert a saw-like effeet. The same saw-like shape might be obtained by composing. as shown in Figs. 4; and 7 withregard to the knives 7, the knives of three or more elements, each element being of trapezoidal cross section. By this arrangement surfaces acting like saws are produced on the side-edges of the knife.

The knives 8 of the finishing cutter C are smooth on the sides, their outer working surfaces are however cut at 10 saw-like so that the side-walls of the incision in the wood and also the point of the incision can be cut easily and cleaning by these saw-like knives. Only the finishing knife 8 possesses in longitudinalsection accurately the shape of the incision to be cut into the wood, the knives 7 being slightly narrower than the knives 8 and the knives 6 being again narrower than the knives 7, so that the roughing knives cut the side-walls of the incision only roughly. these side-walls being out better by the middle knife and the proper shape being given to the side-walls by the finishing knife. All the knives are consequently submitted to the lowest possible stress and any inaccuracies due to eventual giving way of the cutters in lateral direction being avoided so that, at the end of each cutting operation, a perfect acute angled incision has been obtained.

The milling-cutters shown in Figs. 9 to 11 comprise each two groups of knives, the knives of the first group being shorter than the knives of the 2nd group and designed for the rough-cutting, the longer knives of the 2nd group being designed to cut the point of the incision. In this form of construction the longer knives are arranged, so that they can oscillate in the plane of the millingcutter, i. e. give way in rearward direction. Owing to this arrangement the short and the long knives circulate at the same angular speed, i. e. they may be united in one single milling-cutter, the long knives giving way however in rearward direction as soon as they cutinto the wood, so that at the cutting of the wood they retard their movement with regard to the movement. of the stationary knives and when penetrating into the wood they circulate at first with the same circumferential speed as the stationary short knives. The centrifugal force acting upon the long IllVQEs has the tendency to bring these knives into the upright or radial position. Springs might be arranged to assist the action of the centrifugal force upon the knives. The knives are no longer forced through the wood, i. c. they do not strike upon the wood with a hard shock, but their cutting edges are gradually pressed into the wood by the effect of the centrifugal force, eventually assisted by the action of the springs, so that their euttingaction begins when penetrating into the wood with the circumferential speed of the short knives and increases gradually at the cutting through of the wood, so thatconseqnently clear incisions without burr are obtained, burning or breaking of the fine points of the long knives being excluded.

In the form of construction shown in Fig. i) the short roughing knives 11 are rigid with the cutter-disk 12, the finishing knives 13 being oscillatably mounted on bolts 14 of the disk. lhese finishing knives 13 have each an arm 15 by the mass of which the effect of the cei'itrifugal force acting upon the knives 13 and having the tendency to bring these knives into their radial position is increased.

When long knives are used, the centrifugal force of which is sufficiently great, the arms 15 may be omitted.

As shown in Fig. 10 blade'springs 16 are arranged which act upon the oscillatable knives 13 and have the tendency to bring the same into the radial position.

According to Fig. 11 a ring-shaped spring 17 common to all knives 13 is arranged onto which bear flattened portions 18 of the knives 13. The flattened portions 18 terminate in noses 19 by which the ring-shaped spring 17 is compressed as soon as the knives oscillate in rearward direction. The ring-shaped spring 17 is thus put under tension, so that it has the tendency to return the knives 13 into the radial position.

1. A milling-cutter in which the roughing knives and the finishing knives are mounted on one and the same cutter-disk, comprising in combination with the cutter-disk, roughing knives rigid with said disk, and finishing knives mounted in said disk so that they can oscillate in the plane of said disk.

2. A milling-cutter as claimed in claim 1, in which the oscillatable finishing knives have each an arm for increasing the effect exerted by the centrifugal force upon the knives.

3. A milling-cutter as claimed in claim 1, in which blade-springs are arranged in the cutter-disk, one for each oscillatable knife and designed to bring said knives into the radial position.

1. A milling-cutter as claimed in claim 1, in which a ring-shaped spring, common to all oscillatable knives, is arranged in the cutterdisk, each roughing knife having a flattened portion designed to press upon said ringshaped spring. 1

In testimony whereof I affix my signature.

HEINRICH OHAGEN.

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