US1771240A - Thrashing machine - Google Patents

Description

July 22,1930. -w. H. WORTHINGTQN 1,171,240

THRASHING IACHINE Filed Jan. 2l, 1926 2 Sheets-Sheet 1 jizz/@M4021 July 22. 1930. w. H. WQRTHINGTQN 1,771,240

THRASHING MACHINE' rma Jan. 21, 192e 2 snets-sheet 2 @mgm 6;@

Patented JulyV 22, 1930 UNITED STATES PATENT OFFICE i WAYNE I-I. WORTHINGTON, OF BATTLE GREEK, MICHIGANfASSIGNOR TO ADVANCE- RUMELY COMPANY, F LA PORTE, INDIANA, A CORPORATION 0F INDIANA TI'IRASHING MACHINE Application filed January 21, 1926.' Serial No. 82,874.

My invention relates to a method and apparatus for balancing the reciprocating or vibrating parts of a thrashing machine or grainV separator. Y

. In the ordinary grain separator there are generally at least two separate reciprocating racks or tables. One is that usually termed the grain pan or grain conveyor, the other as the straw rack. These two racks are driven from a main crank shaft by pitmen or connecting rods which to accommodate other structural parts are .placed in planes inclined one to the other. Owing to the fact that the racks are supported by swinging links the included angle between the two planes of `these pitmen varies but there is always an average angle between them which may be accurately determined.

Experience shows that when ldriven from atwo-way crank shaft with the two crankV throws in the same plane7 the two vibrating members or racks will most of the time be in balance, theywill be out of balance twice each revolution during a travel of the crank shaft 'subtended by an Yangle substantially equal to the average angle between the two planes of the pitmen and it is this lack of balance of the heavy reciprocating during a part of the crank shaft travelwhich sets up the characteristic vibration in a thrashing machine. I have discovered that if instead of being in the same plane the two throws of the crank shaft are in two planes inclined to each other at an angle equal to the average inclination of the planes of the pitmen, the

two racks will always be in balance.

The reason for this is that when the two throws are in the same plane, one of the racks will still be going forward after the other rack has changed its rearward direction and started forward. When the crankthrows are offset they can be so set that each rack will reverse its direction of movement' at the same time. Other objects will appear from time to time throughout the specication and claims. Y

My invention is illustrated more or less diagrammatically in the accompanying drawings, wherein:

\ Figure l isa fragmentary side'elevation showing a thrasher with my driving mechanism in place;

Figure 2 is a plan view showing the crank shaft;

Figure Sis a vertical cross section on an enlarged scale, taken on line 3 3 of-Figure 2;

Figure 4 is a diagram illustrating the conditions ofbalance in a two throw crank shaft in which the crank pins are 180"` apart and not in balance;

Figure 5 is a similar view showing the crank pins arranged so as to balance;

Figure 6 isa diagram showing a threethrow crank shaft in which the parts are in balance. v

Like parts are illustrated by like characters throughout. Y

Where I have referred to a two throw and three throw crank shaft I mean a shaft in the first cas'eadapted to operate two pitmen or similar devices, and in the second case adapted to operate three.- Such pitmen might be in pairs or singly, or the two throw shaft might as shown have four crank pins operatingin two pairs. Similar conditions might exist in the crank shaft illustrated in Figure 6.

A is the frame of a thrasher. B is a portion of the housing of a thrasher. C is a straw rack and O1 is a'grain pan.

D is a crank shaft having a pair of crank pins D1 D? and. another pair of pins D2 D2. Upon each of the crank pins D1 D1 is mounted one end of a pitman D3, the other end of which is pivoted to the straw rack at D, Mounted at one end on each of the pins D2 is a pitman D5, each of which pivoted at its opposite-end at D6 on the grain pan O1. Y The crank shaft D is carried in bearings D7 supported from a frame A and has at one end a driving pulley D8.

In the diagram shown in Figure t'the crank shaft has a pin X1 and a pin X2. They are placed as shown 180 apart, and the vibrating or reciprocating members of the machine which are driven from these cranks through the two pitmen, do not reach the end of their strokes simultaneously. This is a condition which is essential for proper balancing when two such reciprocating members are employed.

A pitman is attached to each of the crank pins at one end and at the other end to a member which is reciprocated. ln the apparatus to which thepresent application relates generally, the pitmen will be'attached one to a grain pan and the other to a straw rack, the two being mounted to reciprocate along parallel lines. The length of travel of each of the reciprocated parts is indicated by the lines X3 X3 and X4 Xt.

The line X5 indicates diagrammatically the pitman extending to the upper reciproeating member, and the line X6 indicates similarly the pitman extending to the lower reciprocated member. As the crank rotates in the direction of the arrow, the pin X2 moves clockwise, and it is movingaway from the member to which its pitman is attached. Thus this member starts its movement to the left from the point shown in the drawing. The member to which the pitman X6 is attached, which has moved to the right until it has reached the position shown in full lines in the figure, now reverses its direction and moves to the left. The member to which the pitman X5 is attached has been moving to the left until the pin reaches the position shown in full lines. As rotation of the crank continues this member does not yet reverse its direction. ft will not reverse its direction until the line of the pitmen has crossed the center line or axis of the crank, then it will reverse its direction and commence to move to the right. Thus it is obvious that when the crank pins are 180 apart the members to which the pitmen are attached do not reverse their direction of movement at the same time and there is an interval during which the reciprocated members are moving in the same direction and there is therefore an interval of imbalance. lt is one of the objects of this invention to provide a crank arrangement whereby the movement of the reciprocated parts is reversed at the same time so that the two parts are never moving in the same direction and so that they are therefore always in a condition of balance; so that for a brief interval they are standing still, or changing their direction of movement, or else movingl in opposite directions. l

In Figure 5 is shown an arrangement of my invention whereby with a two throw crank shaft two members may be reciprocated in opposite directions and always in balance. While shall describe this form of the invention as having a two throw crank shaft and two pitmen, it is obvious that this number might be multiplied and there might be a pair of throws and pairs of pitmen or any other such arrangement.

In the form shown in Figure 5 the crank 1 corresponds to the crank X2 of Figure t, and

the crank 2 corresponds to the crank X1 of that figure. It will be noticed that the crank 2 has been shifted from its location directly opposite crank 1 so that the angle between the two crank pins 1 and 2 is equal to 180o minus the angle a. This angle a is the angle between the mean center line of the pitmen and cranks 1 and 2. The meaning of the eX- pression mean center line77 will be clear from Figure 5 in which there is shown at the top of the figure a diagram indicating the length of travel of the member to which the pitman, which is attached to crank 2, lis attached. Y represents the left limit of the travel, and Y1 the right limit. It will be seen that Y2 is the mean center line of the angle of travel of the pitman which is attached to the crank 2. The line YS is the mean center line of the angle of travel of the pitman which is attached to the crank 1.

WWhen rotation of the shaft, as shown in Figure 5, takes place in the direction of the arrow, the pin 1 moving clockwise starts its movement to the left and thus the member to which it is attached commences moving to the left. At the same time the pin 2, moving clockwise has already commenced its movement to the right, although the reciproeating member to which it is attached has inst reached its extreme left position and is therefore ready to commence its movement t the right, thus the two reciprocating members reverse their direction. at the same time. This will always take place so that they move in balanced relation.

rlhus the member driven by the pitman attached to crank 2 reaches its inner or left dead center at the same time that the member driven by the pitman attached to the crank 1 reaches its outer or right dead center. This brings the movement of the reciprocating members driven from cach of the two cranks into phase. rlhe only error between their movements and the true sinusoidal movement is that due to the angularity of the respective pitmen, due to their having a finite length, and to the shifting of the reciprocating end of the pitmen, due to snch parts heilig mounted on swinging hangers rather than upon surfaces within the plane of the crank shaft axis. It is this latter component of motion creating, as it does. condition comparable to that in an engine having offset connecting rods, which introduces snch kinematic complications as to cause ns to consider the whole system on the basis of mean center lines of pitmen. rather than upon the inside or outside center lines.

In the form shown in Figure 6 the crank shaft is formed to provide for three reciprocatingmembers which itis desired to balance by having their respective dead centers 120O apart, measured in respect to the crank shaft center. Pitman l is spaced from the mean center line of pitman 3 rby the angle a, and pitman 5 is likewise spaced from the mean center line of pitman 3 by the angle WJ. The order of reciprocation is such that crank 3a shall bring its corresponding reciprocating member to the inside or right dead center, followed by crank da and then by crank 5a. The normal spacing of a three throw crank, is that cranks 3, da, and 52L will'be equally spaced 120 apart. Due to the angles a and b between the several pitman systems, it will be seen that the included angle between cranks 3a and 4a will be equal to the normal angle (1200) minus the angle a between the mean center line of pitman 3 and the mean center lino of pitman 4, when meas ured as described above with reference to Figure 5.

ter line of pitman 3 is spaced 240 minus'the angle b, the angular difference between-the mean center line of pitman 3 and pitman 5.

Although I have shown an operative device, still it will be obvious that many changesl might be made in size, shape and arrangement of parts without departing materially from the spirit of my invention; and I wish, therefore, that my showing be taken as in a sense diagrammatic.

The use and operation of my invention are as follows:

As shown in the first three figures a four throw crank shaft is used, the throws or crank pins being in pairs. Conditions are those described and shown in detail in connection with Figure 5.

There are two reciprocating parts, a straw rack and a grain pan. These two are reciprocated from the crank by means of the pitmen. The balanced condition described in detail in connection with Figure 5 exists in the form ofthe invention shown in Figures 1 to 3, and the straw rack and grain pan thus move in the opposite direction and they reverse their direction of movement at the same time.

I claim:

1. In a thrasher, a plurality of members mounted for reciprocation and means for reciprocating them in balanced relation, said means including a rotating crank shaft, said shaft so formed that the members all reverse their direction of movement at the same time, said members mounted one above the other, the axle of the crank shaft being positioned below the lowest member.

2. In a thrasher, a plurality of members mounted on different levels for reciprocation and means for reciprocating them in balanced relation, said means including a rotating crank shaft, said shaft so formed that the members all reverse their direction of movement at the same time, said members mounted one above the other, the axle of the crank shaft being positioned below `the lowest member.

Likewise pitman 5 which would normally be spaced 2400 from the mean een' 3. In a thrashing machine a plurality of members mounted on different levels for reciprocation, means for reciprocating them and for causing them to move in balanced relation, including a rotating crank shaft from which they are driven, said shaft provided with a plurality of crank pins or throws, the same being so arranged with relation to each other that they cause Vthe members which are driven from them to reverse their Adirection of movement at the same time, said membersmounted one above the other, the axle of the crank shaft being positioned below the lowest member.

4c. In combination a. plurality of parts separately mounted for reciprocation and means for moving them in balanced relation including a rotating crank shaft having a pin or throw for each such part and a pitman connecting each such part to its pin, each throw being spaced from its adjacent throw a distance equal to 360o divided7 by the total number of throws minus the angle included between the mean center line of the two adjoining pitmen, said members mounted one above the other, the axle of the crank shaft being positioned below the lowest member.

5. In combination a plurality of parts separately mounted for reciprocation on Adifferent levels and means for moving them in balanced relation including a rotating crank shaft having a pin'or throw'for each such part Aand a pitman connecting each such part to its pin, each throw being spaced from itsY adjacent throw a distancer equal to 360O1divided by the total number of throws minus the angle included betweenthe mean center line of the two adjoining pitmen, said members mounted one above the other, the axle of the crank shaft being positioned below the lowest member.

6. In combination a pair of parts separately mounted forreciprocation and means for moving them in balanced relation including a rotating crank shaft having a pair of pins or throws and a pitman connecting each part with one of such pins, the pins being spaced apart a distance equal to 180D minus the angle included between the mean center line of the two pitmen, said members mounted one above the other, the axle of the crank shaft being positioned below the lowest member.

7. In combination a pair of parts separately mounted for reciprocation on-different levels, and means for moving them in balanced relation including a rotating crank shaft having a pair of pins or throws and a pitman connecting each part v`with one of such pins, the pins being spaced apart a distance equal to 180o minus the angle included between the mean center line of the two pitmen, said members mounted one above the lli) other, the axle of the crank shaft being positioned below the lowest member.

8. In a. thrasher, a plurality of members mounted for reciprocation and means for reciprocating them in balanced relation, said means including a rotating crank shaft mounted beneath such members, said shaft so formed that the members all reverse their direction 01"' movement at the same time, said members mounted one above the other, the axle of the crank shaft being positioned below the lowest member.

9. In a thrasher, a plurality of members mounted on dii'ferent levels for reciprocation, and means for reciprocating them in balanced relation, said means including a rotating crank shaft mounted below such members, said shaft so formed that the members all reverse their direction of movement at the same time, said members mounted one above the other, the axle of the crank shaft being positioned below the lowest member.

10. In combination, a pluralityT of members separately mounted :for reciprocating movement on different levels and means for moving all of them in balanced relation including a rotary crank shaft ha fing a pin or throw for each such part, and a connecting rod connecting each such part to its throw, each crank throw being formed in a plane inclined to the plane of the adjacent crank throw at an angle equal to the average inclination of the plane of the connecting rod attached to said crank throw throughout the several positions of movement of said connecting rod, said members mounted one above the other, the axle of the crank shaft being positioned below the lowest member.

Signed at Battle Creek, county of Calhoun, and State of Michigan, this 18th day of January, 1926.

WAYNE H. VORTHINGTON.

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