US1396600A - Rotary cutter - Google Patents

Description

A. M. SIMPSON.

ROTARY CUTTER. APPLICATION FILED auuz21. 1921.

1,396,600. WMNOV. 8,1921.

,Fgz. 2:1 2.

UNITED STATES PATENT OFFICE.

ROTARY CUTTER.

Application filed June 27, 1921.

To all whom it may concern:

Be it known that I, ALFRED M. SIMPSON, a citizen of the United States, residing in the city of Honolulu, Territory of Hawaii, have invented certain new and useful I'mprovements in Rotary Cutters; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains, to make and use the same.

The invention relates to rotary cutters for sugar cane and the like, and has for its object to provide a simple, strong, durable and efficient device of the character indicated, comprising a shaft and a plurality of knives having radial blades spaced along said shaft and rigidly secured thereto by suitable means, which admit of individual knives being readily removed and replaced, and which also prevent the distortion of the knives under heavy stresses imposed thereon in the cutting operation.

The invention is illustrated in the accompanying drawings, in which Figure 1 is a vertical side elevation of a single knife and the associated shaft, the latter being shown in section;

Fig. 2 is a front elevation of a section of the shaft having a number of knives secured thereto; and

Fig. 3 is a horizontal section on line 33 of Fig. 1, with the shaft omitted.

Referring to the drawings, 1 indicates a shaft, which is preferably cylindrical in form and is provided with a series of longitudinal keyways 2, spaced at regular intervals about the periphery thereof and serving as part of the primary means for locking the individual knives to the shaft. In the particular embodiment of the invention illustrated, four of said keyways are shown spaced 90 apart.

Each of the knives comprises a hub section 3, which is relatively thick, terminating body portion of each cutter being formed as an integral casting, which, because of the Specification of Letters Patent.

Patented Nov. 8, 1921.

Serial No. 480,811.

is exceptionally strong and is effective in resisting the tendency of cutters of this character to rupture at the points of juncture between the blades and the hub. The hub 3 is provided with a central shaft-engaging opening 4, the major portion of which hugs the shaft, said opening 4 being extended laterally of one side of the hub, as an open throat to permit the cutter to be passed over the shaft. Formed in the body of the hub at each side of the open throat is a shoulder 7, provided with a generally rectangular recess 8 in the bottom thereof. Each of the shoulders 7 is also provided with a tapped bolt hole 9, which preferably registers centrally with the corresponding recess 8.

The throat or lateral opening in the hub 3 is closed by a cap 10, the inner surface of which conforms with that of the shaft 1, which it closely engages when in position, and is provided with lateral wings 11, which engage the shoulders 7 in the hub, each of said wings being provided with a rib or boss 12, which fits in the recess 8 in the corresponding shoulder 7. The arcuate shaftengaging surface of the cap is provided with a keyway 17, adapted to receive a key 15, which is substantially rectangular in cross section and extends beyond the face of the cap to engage one of the keyways 2 in the shaft 1. The key 15 is provided with a central transverse openin to receive a bolt 16, by means of which the key is securely locked to the cap. It will be particularly noted that the key 15 is of a length slightly greater than the thickness of the hub 3, so that the ends of the key project slightly beyond the lateral faces of the hub. The cap is secured to the hub by any suitable means, but preferably by threaded bolts which are passed through bolt openings in the wings 11 and screwed into the bolt openings 9 in the body of the hub. The outer end of each of the bolts 18 is provided with a double lock nut 1%, by means of which the caps are drawn into close interlocking engagement with the huh, as shown.

In assembling the rotary cutter, the sevcral knives are mounted on the shaft with the radial blades of alternate knives at right angles to each other, which is effected by sliding the knives laterally over the shaft and then applying each cap 10 to its hub, so that the key 15 carried by each cap will engage the appropriate keyway 2 in the shaf The provision of four keyways 2 in the shaft enables the knives tobe so disposed that the key connections between the successive knives of the series will be spaced 90 apart around the shaft, thereby distributing the torsional stressesevenly about the shaft and reducing the tendency of the knives to rupture or twist off, which is a common faultin devices of this character when a single keyway in'the shaft is provided for connecting all the knives thereto. It will alsobe noted that the interlock between the wings 11 of the cap and the shouldered recesses 7 in-the hub, and also between the ribs 12 on the wings 11 and the recesses 8 in the shoulders 7 of the hub, materially strengthens the structure and prevents any opening or distortion of thethroat of the hub due to the heavy" stresses imposed upon the cutters when in operation. Then the caps 10 have beenset firmly inposition by means of the lock nutslelengaging the threaded bolts 13, the concave faces of the caps afford an additional clamping means for securing the cutter'to the shaft and materially lessening the shearing stresses on the keys 15.

"From the foregoing descriptionit will be apparent that the device involves material improvementsancl advantages over former types of rotary cutters,and among the points ofsuperiority in this particular construction maybe mentioned the following :The'hub andthe blades are cast integral, which admits of a relatively wide filleted shoulder, suchas5, being formed between the hub and the knives, which greatly strengthens the individual cuttersandeliminates the tendenc'y to rupture, which is common in the older types of cutters, wherein the knives are either bolted to ahub 'or' clamped between adjacent hubs. Each hub being held in'its position independently of all other hubs, and there being no side strain between adjacent hubs, thetendency of the shaft to twist or distort under the heavy torsional strain is practically eliminated. This matter of distortion of'the shaft'has proven a serious difficulty. in all former types of cutters of this general character, in which the hubs of'the several knives are clamped together by longitudinal bolts or by heavy nuts on the ends of the shaft. The provision of the keys 15 of slightly greater length than the thickness of the hubs, so that the ends of the keys project beyond the lateral faces of the hubs, affords an effective spacing means to hold the knives in proper spaced relation, so that adjacent hubs do not contact and, therefore, do not tra nsinit the strains imposed thereon to adjacent hubs or cutters. Any one of the cuttersmay be readily replaced without moving or in any way interferlng with the adjacent cutters. The perfect balance of the apparatus will-not be disturbed even if one or more of the cutters is removed entirely.

' What I claim is:

1. A rotary cutter comprising a shaft having a series of peripherally spaced longitudinal keyways therein, a series of separate knives mounted on said shaft, each knife including a thick hub section and thinner integral radial blades, and separate keys connecting the knife hubs to the shaft, each key having a length greater than the thickness of the hub and serving to engage and space adjacent knives.

2. A rotary cutter comprising a shaft having a-series of peripherally spaced longitudinal keyways therein, a series of separate knives -mounted on said shaft, each knife including a thick'hub section and integral radial blades having filleted shoulders at their junctions with the hub sections, and separate keys connecting the knife hubs to the shaft, eachkeyhaving a length greater than the thickness of the hub and serving ooenin' a ca closin said 0 enin and radial blades, and keys engaging keyways in the shaft and knivesto lockthe latter to the shaft.

5. A knife forrotary cutters comprising a central hub, integral radial blades of less thicknesshaving filleted shoulders at their junctions withthe hub sections, said hub having a shaft-engaging opening and a lateral opening communicating therewith, shoulders formed adj acent said lateral opening, a cap fitting said lateral opening and engaging said shaft, means for securing the cap to the hub, and a key carried by the hub for locking the knife to a shaft.

6. A knife for rotary cutters comprising a central hub, integral radial blades of less thickness thanthe hub, said hub having a shaft-engagingGopening, a lateral opening communicating therewith and having shoulders formed thereon at the sides of said lateral opening andha'vin'g recesses therein, a cap fitting said 'lateral opening having a shaft-engaging portion andwings engaging said shoulders, lugs on said wings engagin said recesses, and means for locking sai cap to the hub.

7. A knife for rotary cutters comprising a central hub, integral radial blades of less thickness having filleted shoulders at their junctions with the hub section, said hub having a shaft-engaging opening and a lateral opening communicating therewith and shoulders formed thereon adjacent said lateral opening, a cap fitting said lateral opening and engaging said shaft, means for securing the cap to the hub, said cap having a keyway in its inner face, and a key in said keyway to engage the keyway in a supporting shaft.

8. A knife for rotary cutters comprising a central hub, integral radial blades of less thickness than the hub, said hub having a shaft-engaging opening, a lateral opening communicating therewith and having shoulders formed thereon at the sides of said lateral opening and having recesses therein. a cap fitting said lateral opening having a shaft-engag1ng portion and wings engaging said shoulders, lugs on said Wings engaging said recesses, said cap having a keyway on its inner face, and a key in said keyway to engage the keyway in a supporting shaft.

9. A knife for rotary cutters comprising a central hub having a shaft-engaging opening with an open lateral throat, a cap closing said throat and having a keyway in its inner face, a key secured in said keyway means to secure the cap to the hub, and radial blades formed integrally with said hub.

In testimony whereof I aflix my signature.

ALFRED MERVYN SIMPSON.

Images