Knife support structure
US 3126931 A
Description (OCR text may contain errors)
March 31, 1964 A. w. BLANSI-IIINE ETAL KNIFE SUPPORT STRUCTURE Filed June 29, 1961 2 Sheets-Sheet 1 INVENTORS ALLISON W BLANSHINE 6ERHARD LOCKER ATTORNEF' March 1964 A. w. BLANSHINE ETAL 3,126,931
KNIFE SUPPORT STRUCTURE Filed June 29, 1961 2 Sheets-:Sheefc 2 INVENIWKS ALLISON W. BLANSHINE GERHARD LOCKER A TTO/Y/YE Y Patented Mar. 31, 1964 3,126,931 KNIFE SUPIQRT STRUCTURE Allison W. Blanshine, Lititz, and Gerhard Locker, Flew Holland, Pen, assignors to Sperry Rand Corporation, New Holland, Pin, a corporation of Delaware Filed June 29, 1961, Ser. No. 12(l,5'7-l 6 Claims. (Q1. l te-4.07)
This invention relates to rotary cutters for forage harvesters and the like, and more particularly to improved support structure for the knives of a rotary cutter.
In one common type of forage harvester, crop material is fed into a housing where a cutter chops the material and then discharges it to a trailing wagon. The cutter rotates about a fixed axis and has a plurality of knives angularly spaced around said axis which successively cooperate with a stationary bar. The knives extend diagonally relative to the cutter axis whereby each knife on passing the stationary bar exerts a shearing action on the material.
If cutterhead knives are straight and diagonally mounted relative to the cutter axis, their cutting edges will generate a hyperboloid, rather than a true cylinder. To achieve a good cutting action it is necessary either to bow the stationary bar to conform to the hyperboloid generated or leave the shear bar straight and bow the cutter knives so that their edges will generate a cylinder. Where the cutter knives are cup-shaped for throwing and blowing purposes, they are commonly bowed and twisted on expensive compound helical dies so that their cutting edges will be properly located. Bowing and twisting the knives makes mounting the knives on cutter structure more complicated.
One object of this invention is to provide supports for cutter knives wherein the knives are segments of true cylinders, all supports being of the same construction and each knife being mounted on a plurality of spaced supports.
Another object of this invention is to provide knife supports for a rotary cutter of the character described, said supports having seats which match with all portions of each knife whereby three or more supports may be used, as desired, for each knife and the engagement of one support with an associated knife will be the same as the engagement of other supports with the knife.
Another object of this invention is to provide knife supports of the character described having improved means for connecting the knives to the supports.
A further object of this invention is to provide knife supports of the character described which are rigid and knives which are resilient, each support having a knife seat specially designed for proper engagement and support of its associated knife.
A still further object of this invention is to provide a knife support structure wherein all knife support members are of the same design and adapted to be speedily and economically manufactured.
Other objects of this invention will be apparent hereinafter from the specification and from the recital in the appended claims.
In the drawings:
FIG. 1 is a longitudinal vertical section through a rotary cutter having knives mounted on supports constructed according to this invention, such section being taken generally on the line 11 of PEG. 2 looking in the direction of the arrows;
FIG. 2 is a section taken on the line 22 of FIG. 1 and showing the rotary cutter in plan and one knife with the supports therefor;
FIG. 3 is a rear perspective view, on an enlarged scale, of one of the knife supports;
FIG. 4 is a side elevation of the support; FIG. 5 is a fragmentary front view of one of the suports; p FIG. 6 is a view showing an opening in one of the cutter knives to receive the fastening means for connecting the knife to the cutterhead supports;
FIGS. 7 and 8 are perspective views showing one of the fastening bolts used in this design, FIG. 8 looking at the bolt ninety degrees from the position shown in FIG. 7; and
FIG. 9 is a generally diagrammatic view illustrating in dotted lines the relationship of a knife and a support prior to connection of the parts and in solid lines the knife and support after connection.
Referring now to the drawings by numerals of reference, and first to FIGS. 1 and 2, Jill denotes a blower housing which is generally cylindrical when viewed in side elevation. The housing 10 has side walls 11 which support a horizontally extending transverse shaft 12 of a rotary cutter 15. Suitable bearings 16 are provided for journalling shaft 12 in side walls 11. The shaft 12 has three radially extending support discs 18, which are normal to the shaft axis and spaced relative to each other along the axis of the shaft. Each disc 18 carries six support members 2% (FIG. 1) for cutter knives 21.
When viewed as shown in FIG. 1, the cutter 15 rotates in a clockwise direction as indicated by the arrow 22. Crop material is fed into the housing through inlet opening 24 in the forward part of the housing. The knives 21 successively cooperate with a stationary shear bar 25 and after materialis severed, it is swept along the arcuate bottom portion 26 of the housing and then thrown and blown through discharge opening 28 and spout 29. The spout 29 usually extends to a point where discharged material will be deposited in a trailing wagon or the like. The housing 10 and the shear bar 25 are supported on frame structure including a cross pipe 30. Forwardly of the inlet opening 24, a pair of infeed rolls, namely upper roll 31 and lower roll 32, are provided. The lower roll 32 is cylindrical and smooth while the upper roll 31 has transverse slats which provide an aggressive feeding action on the incoming material. The material is fed across a support floor 34 and over shear bar 25 where the knives 21 engage it. The rotary cutter 15 rotates at high speed whereby the incoming material is cut in relatively short pieces.
Shear bar 25 has a straight cutting edge. The knives 21 have cutting edges 35 which are so curved that on rotation of the cutter they generate a true cylinder. As shown best in FIG. 2, each knife 21 extends diagonally relative to the axis of the cutter shaft 12. The curved cutting edges 35 eliminate the generation of the hyperboloid on rotation of the cutter, which would be the case if the edges were straight. Each knife 21 is formed of a segment of a true cylinder, all portions of each knife being concentric with the longitudinal axis of such cylinder. After crop material is cut, it is caught in the cup of the knife and thrown and blown through the discharge opening 28.
Each knife 21 is mounted on a set of three supports 20. A greater number can be used if desired, the number required depending upon the axial length of the cutter. As illustrated best in FIGS. 3-5, each support'comprises a body portion 40, shaped as shown, and having two transverse openings 41 for fastening bolts 38 (FIG. 1) whereby the supports may be fastened to the discs 18. At its radial outer end, each support has a seat 42 which is semicylindrical, the curvature matching with the curvature of the knives 21. Each knife has a concave forward face 44, relative to the direction of rotation of the cutter 15, and a convex rear face 45. The rear curved face 45 of 3 each knife fits against the seats 42 of its associated sup ports.
As shown in FIG. 2, the set of three supports 29 for a given knife are angularly displaced relative to each other as well as axially spaced. The three seats 42 of these supports are located contiguous to the segment of a cylinder which the knife comprises.
The knife supports '20 are rigid and made of cast metal. When cast, a depression 46 is formed in the rear of each support and an opening 48- is provided which extends from depression 46 through to the middle of its seat 42.. The opening 48 is located substantially midway between the radial inner end 59' of the seat 42 and the radial outer end 51 thereof. Each knife has three holes 52, each of which is formed as shown in FIG. 6. The holes -2 are rectangular in form and elongate, the elongation being in a radial direction relative to the cutter when the knives are mounted thereon. The knives are fastened to the supports 20 by bolts 55 constructed as shown in FiGS. 7 and 8. Each bolt 55 has a head 56, a threaded shank 58 and a rectangularly shaped neck 59 between the head and shank. When shank 58 is projected through 'an opening 52 in knife 21, and passed :through the opening 48 in the support 40, a nut can be threaded onto the shank to thereby fasten the knife to the support. The nut for the bolt fits into the depression 46. The head 56 of each bolt has a curved inner face as adjacent the neck 59. The curvature 60 matches with the curvature of the concave inner face 44 of each knife 21. The rectangular neck 59 fits snugly into the opening 52 and the bolt is prevented from turning. In like respect, the curved inner face of the head 56- fits snugly against the inner face of each knife and provides a neat, compact structure.
The elongate rectangular openings 52 in the knives provide for radial or outward adjustment of the knives relative to the cutter to compensate for wear. Each support 20' is provided with an adjustment bolt 61 which threads through carrier portion 62 of the support. The end of the adjustment bolt engages the radial inner edge of the knife and can be used to adjust the knife radially outwardly after the fastening bolts 55 have been loosened.
As shown in FIG. 5, each seat 42 is generally ovalshaped, being wider at the middle than at its ends and being elongate in a radial direction. As shown, the opening 52 is of smaller size than its associated wide portion of the seat 42 whereby a good solid seat is provided for the knife.
Theoretically, in manufacture, the knives 21 comprise segments of a true cylinder and the seats 42 are concentric with such cylinders. However, to allow manufacturing tolerances and variations to reduce costs, the knife support seats 42 are so designed relative to the knives 21 that when each knife is initially placed against its three supports, there is engagement first between the knife and the radial inner and outer ends 50* and 51 of the seats 42, as shown in dotted lines in FIG. 9. Some very small spacing may exist between the portion of the knife between these radial ends and the knife seat center. However, the supports are rigid and each knife has some resiliency. Therefore, when the bolts 55 are applied to fasten the knives to the supports, the knives bow inwardly slightly at their middle whereby they have firm engagement with each seat 42 for the full arcuate extension of the seat.
With this structure, all supports are identical and each support has the same engagement with the knives as the other supports. The neck portion 59' of each bolt and the curved inner face 6th of each bolt head 56 prevents each bolt from turning when in mounted position.
While this invention has been described in connection with one embodiment thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as fall within the scope of the invention or the limits of the appended claims.
Having thus described our invention, what we claim is:
l. A device for chopping and throwing forage material comprising a housing having a forwardly located inlet, a rearwardly located outlet and a pair of vertical side walls at opposite sides respectively of the inlet and outlet, a shaft rotatably supported on said side walls and having an axis perpendicular to the walls, a plurality of discs carried on said shaft and spaced from each other along the axis of the shaft, said discs projecting radially from said shaft and parallel ,to said side walls, a plurality of knives anguiarly spaced around said shaft axis and supported on radial outer ends of said discs, said shaft being rotatable in such direction that the knives move past said inlet and then along said housing to said outlet, the portion of said housing between said inlet and outlet being generally concentric to said shaft axis, each knife having a longitudinal axis diagonal to said shaft axis and being so curved about the longitudinal axis that each knife as a whole is in the form of a segment of a true cylinder, each knife having a concave face in the direction of travel of the knives and a convex face away from the travel direc tion, the space in front of each concave knife face from one knife to the convex face of the next being substantially unobstructed and each knife exerting a throwing action on material, and mounting means for each knife comprising a set of rigid supports, one on each of said discs, the supports in each set being angularly spaced relative to each other and all supports being the same, each support having a semi-cylindrical seat having a radial inner end and a radial outer end which engage radial inner and outer ends of the convex face of its associated knife, each support seat having a curvature which substantially matches the knife curvature and forms a segment of the same true cylinder, and means located bet-ween said radial inner and outer knife ends for fastening the knives to the supports.
2. A rotary cutter as recited in claim 1 wherein there are at least three supports for each knife.
3. A rotary cutter as recited in claim -1 wherein said fastening means comprises a fastening bolt for each support, the bolt shank extending through the knife for conneotion to said support and the bolt head engaging the concave forward face of the knife, said bolt head having a knife engaging side curved to conform with the curvature of the knife.
4. A rotary cutter as recited in claim 3 wherein each support seat is of oval shape, eing longer in a radial direction than in an axial direction, and being wider in the middle than at its ends.
5. A rotary cutter as recited in claim 3 wherein each knife has an elongate radial opening for each bolt, and each bolt has a neck which passes through said opening, the size of said neck being such relative to the size of said opening that the knife is adjust-able in a radial direction only relative to the cutter axis.
6. A rotary cutter as recited in claim 5 wherein said opening and bolt neck are rectangular and in such engagement that said bolt is prevented from rotating relative to the knife.
References Cited in the file of this patent UNITED STATES PATENTS 332,854 Woods Dec. 22, 1885 1,076,714 Stanat Oct. 28, 1913 1,639,807 Oppenheim et a1 Aug. 23, 1927 1,929,586 Holland-Letz Oct. 10, 1933 2,450,277 Frudden Sept. 28, 1948 2,573,887 Aas-land Nov. 6, 1951 2,747,634 Klemm et al. May 29, 1956 FOREIGN PATENTS 23,638 Great Britain of 1914