US2179159A - Tractor - Google Patents

Description

Nov. 7, 1939. J H. MCCOLLOUGH TRACTOR Filed April 21, 1957 4 Sheets- Sheet 1 N NE: wik m IN VENT OR yowczeazlli l A-r'rorzu Y Nov. 7, 1939. .1. H. McCOLLOUGH TRACTOR 4 Sheets-Sheet 2 Filed April 21, 1937 rlqunzz 4 @Iffl'fon flaw ATTORIYEY Patented Nov. 7, 1939 UNITED STATES rA-TENT OFFICE 'rnaoron' James H. McCullough, Alameda, Califl, assignor to Universal. Engine & Propeller Companma corporation of California Application April 21, 1937, Serial No. 138,160 2 Claims. (o1. 1s0- 1 f The present invention relates particularly to the single track type of tractor such as disclosed in my Patent No. 1,738,784, dated December 10, 1929.

In tractors of this class, where the whole pulling unit is adapted to be steered by the operator from an attached vehicle, it is essential that the total weight of the pulling unit be kept to a minimum, while still allowing the same pulling capacity, and this can only be accomplished by moving the center of Weight of the pulling unit forward and placing the pivotal point of attachment of the pulling unit to the vehicle as close to the ground as possible. Such an arrangement would result in securing the greatest pulling capacity with the least amount of forward weight, and the tractor could be relied upon to pull its full track capacity while keeping the track fiat upon the ground. Furthermore, when the tractor is operated in reverse, with the pivotal point of connection between the pulling unit and the vehicle as close as possible to the ground, it does not have as great a tendency to raise the track at the rear, which allows the forward weight to be effec- 5 tive in rotating the weight down in front and the rear of the track up approximately about the center of the front track idler.

It is, therefore, one object of the present inven tion to provide a tractor of the character indi- 30 cated wherein the center of weight of the pulling unit is moved forwardly and the point of connection between the pulling unit and the vehicle is moved downwardly close to the ground to attain the desired results set forth.

5 It is another object of the invention to provide means for controlling the relative movements of the pulling unit and vehicle when the tractor-is moved either forwardly or in reverse over uneven ground. .1

40 It is still another object of the invention to provide engine controls operative from the vehicle and so arranged as to be always effective regardless of the relative angular positions of the pulling unit and vehicle.

45 It is also an object of the invention to provide a novel and compact transmission between the engineand track with, of course, suitable clutch and reverse mechanism.

Finally, it is an object of the invention to pro- 50 vide a tractor of the character indicated that will be economical to manufacture, simple in form and construction, light in weight without sacrifice of pulling capacity, and highly efficient in its practical application. I.

55 In the drawings:

Figure 1 is a perspective illustration of a tractor embodying my invention, with parts broken away. Figure 2 is a detail illustration of the clutch pull assembly, partly in section. Figure 3' is a side elevation of a portion of the 5 tractor.- 1 Figure 4.- is a side elevation of a portion of the pulling unit, enlarged, and showing a part of the clutch operating means and'governor control. Figure 5 is'a half-section, enlarged, through a 10 portion of the transmission mechanism, taken on line 5-5 of Figure l, the central portion being broken away. a

Figure 6 is an enlarged section on line 66 of Figure 1 a Figure is an enlarged section on line l-1-of Figure 1.

Figure 8 isan enlarged illustration of the clutch operating means, with a part broken away. Figure 9 is a diagrammatic illustration showing 20 the track-carrying sprockets and their cooperating elements.

The pulling unit comprises the structure indicated generally at I, with side plates 2-2a between which are journaled sprockets 3 and 4 carryingftrack 5, and driven by a chain and sprocket drive 6 from sprocket l on shaft 8 of engine 9.

That portion of the'tractor which I term the vehicle, or pulled unit, comprises a fork l0 having a wheeled structure I I pivotally connected thereto as at' l2, with the steering gear indicated generally at [3." 1 As hereinbefore stated an important feature of the invention is the position of the pivotal connection between the pulling unit and the vehicle. The ideal position of this connection would be at the rear end of the pulling unit andat the bottom level of the track, but since it cannot be placed that low I carry the side plates 2-2a as close to that level as possible and then mount the fork ill 40 as low as possible on these plates.

' The mounting of each leg of the fork on its adjacent'plate is shown clearly in Figure .7 where a bearing [4 is inserted in the lower end of the leg and on a stub shaft l5. The shaft i5 is fixedly mounted in plate 2 by means of a collar l6 seated on its bevelled portion l1 and having a flange 18 engaging a plate I!) on the inside of. plate 2. A nut Zllis threaded on to the end of the shaft to bear against the inner portion of bearing lkand ring 2| on fork I0 supports the outer race of bearing M. 'A cap 22 is mounted on the leg to cover the end of shaft [5.

The engine in its entirety is mounted forwardly oflthe axis of the front track sprocket with its shaft 23 lying approximately in the plane of the top of the track and carrying a gear 24 meshing with an idler gear 25 mounted in the engine casing 26 as at 21. This idler is provided with a clutch member 28 engageable with a secand clutch member 29 on a crank 30 and through the medium of which the shaft 23 may be turned over to start the engine.

When the tractor is in operation power is transmitted from the engine shaft 23 and gear 24 through idler 25 to drive shaft 8 in the following manner.

On the engine casing 26 is formed a housing 3| and in this housing the shaft 8 is rotatably mounted as at 32. On the end of this shaft remote from sprocket 9 with its hub portion inserted between bearing 32 and the shaft, is a gear 33 carrying pins as 34 which in turn support a plate 35 in parallel and spaced relation to the gear. This gear 33 meshes with idler gear 25 and of course is driven continuously when the engine is in operation.

In order to effect a driving connection between gear 33 and shaft 8 when the tractor is to be put in motion, a disc clutch 36 is inserted between the shaft 8 and the pins 34. A plate 31 is slidably mounted on the pins to overlie the clutch plates and is normally urged to bring the plates into driving contact by springs as 38 inserted between the plate 3'! and plate 35. The plate 31 is mounted on a worm shaft 39 through the medium of ball bearing 45 because it rotates with respect thereto.

The worm shaft 39 operates in a worm nut 4| in housing 3| and is advanced or retracted as desired by means of an arm 42. When the arm 42 is moved in the direction indicated by arrow 43 by means of spring 44, then the plate 37 is allowed to be moved by the urge of springs 38, thereby engaging the clutch and effecting the drive to shaft 8. When the arm 42 is moved in the opposite direction as hereinafter described the springs 38 are compressed by plate 37 to disengage the clutch from drive shaft 8.

Since the clutch is automatically moved into an operative position by the action of spring 44 the following mechanism is provided for moving it into an inoperative position.

A lever 45 is mounted on a pin 46 which in turn is rotatably mounted in a sleeve 41 on housing 3|. This lever has a foot 48 engaging a roller 49 on arm 42, the foot having an arcuate edge 50 so that when the lever is pulled to swing foot 48 upwardly it operates to move the arm 42 to disengage clutch 35. The lever is connected to the housing by spring 5i operative to move foot 48 downwardly and allow spring 44 to function as described.

When, therefore, the lever 45 is in a vertical position spring 44 swings arm 42 to the limit of its movement in the direction 43 and the clutch is engaged. When the lever is pulled into the position shown in the drawings, Figure 4, the arm 42 is operated to disengage the clutch as described.

While the lever 45 is moved in one direction by the pull of spring 5i, it is moved in the other direction, that is to disengage the clutch, by means of a cable operated from the vehicle part of the tractor. Since the cable must operate over sheaves, and since the pulling unit and vehicle are subject to relative movement about their pivotal connection at I 5, it became necessary to provide means to keep the cable tight at all times on the sheaves, regardless of the fact that the relative motion of the tractor unit and vehicle causes a lightening or slackening of the cable on the sheaves. This was accomplished in the following manner.

To the outer end of lever 45 is pivotally connected a bracket 52 as at 53, the bracket having an outwardly extending finger 54 to which is connected a spring 55, the other end of which is connected to the lever as at 56. In the bracket 52 is secured'one end of an eyebolt 51 to which the operating cable is connected. The cable 58 passes over sheaves as 59 on the vehicle part of the tractor and is fastened as at 60 to a hand-grip 6i slidably mounted on around bar 62. The bar 62 has an aligned row of notches 63 formed in one side thereof, and the grip has a pin 64 mounted therein and urged into engagement with the bar by a spring 65. The grip may be turned to move the pin out of engagement with any notch, and it may then slide freely back and forth on the bar. When so positioned the spring 5| operates to swing lever 45 upwardly about its axis and permit the engagement of the clutch 36 as described, the grip then being turned so that the pin 64 will engage a notch.

Since, due to the position of the point 53 relative to the point 54, the pull of the spring 55 increases as the angle between the lever 45 and eyebolt 57 becomes smaller it operates to hold the cable taut regardless of changes in the angular relationship between the pulling unit and vehicle unit.

The bar 62 is mounted on the steering wheel assembly by means of a bracket 66 and a balland-socket joint 5? so that the cable may be adjusted in alignment whenever the steering gear is changed in position on account of a change in the vehicle used. It is to be understood that various farming implements may be substituted for the wheeled structure shown, the change being made adjacent the fork Iii as at 6B.

In order to operate the tractor in reverse I provide a clutch drive spider 69 which is keyed to the shaft 8 adjacent the end carrying sprocket 5, and is provided with pins as 75.

A reverse clutch gear fl is rotatably mounted on sleeve 42 on shaft 3 adjacent spider 69, and this gear meshes with an idler pinion 73 which in turn meshes with a pinion l4 keyed to a shaft 15 mounted in bearings H6 in housing 3!. The shaft 15 carries the fan belt drive pulley TI on one end and a gear 78 at the other end meshing with gear 33. Since gear 33 rotates continuously in one direction it follows that gear H is driven continuously in the opposite direction.

Slidabl mounted on shaft 8 and pins 70 is a clutch member 19 movable into and out of engagement with the clutch gear ll. This member is normally held out of engagement with the gear by a spring 83 inserted between the spider 69 and shoulder 8! on member 15. To move the member into engagement with the gear I provide a collar 82 seated against the outer shoulder 83 on the member 79 and carrying pins as 84. Engaging the pins 84 is a yoke 85 pivotally mounted on housing 3! as at 35 and having a bell-crank arm 87 with a head 83. On the sleeve 45 carrying lever 45 is mounted an arm 83 fitted with a pin 93 engageable with the head 88.

The result of the above described mechanism is that when the cable 58 is pulled while the engine is idling the member 79 is moved into engagement with the clutch gear H and the shaft is operated in reverse through the medium of the pins l0 and spider 63. It is also particularly pointed out that by means of the simple necting the said pulling unit and the vehicle as hereinbefore set forth accomplished certain most desirable results, certain undesirable character istics, both when pulling and when operating in reverse, were still apparent when the tractor was being operated over uneven ground. There was a tendency for it to operate with the forward end bobbing up and down, resulting'in an operation of the track not at all times in full contact of its length upon the ground. And when the tractor was operated under light load conditions this objectionable movement was the more noticeable. When the tractor was operated in reverse, in spite of the lowered position of attachment of the fork to the frame, the rear end of the track would rise to an objectionable degree.

Both of the disabilities above described have been overcome by the use of a heavy coil spring 9| attached to one side fork ID by means of a strap 92 engaging a bolt 93, and to the pulling unit at 94. Whenever the angularity between the fork I8 and the pulling unit increases for any reason, the spring operates to pull the fork and its load forwardly on its pivotal point i5 and so throw an increasingly heavy weight on the pulling unit at this point, this automatic increase in weight on the rear end of the tractor steadying the machine and holding the rear end down.

The above described arrangement of the spring allows the track unit to rise until the forward edge of the fork I0 contacts stop 95'. With the strap in this position there is no action of the spring since the strap slides on bolt 93, but when the front end lowers the strap engages bolt 93 and the spring progressively tightens to prevent a further downward movement of the front end of the pulling unit, and transfers weight tothe rear portion of the track as above set forth.

This action also comes into play when the tractor is operated in reverse to the end that the track is kept nearer to a level position on the ground when operated in reverse.

It is, of course, to be understood that while I have herein shown and described one specific embodiment of the invention, changes in form, construction, and method of assembly and operation may be made within the scope of the appended claims. J

I claim:

1. A tractor comprising, a track-laying pulling unit having a forwardly overhanging power plant operatively associated therewith, an up- "in one direction, and resilient means inserted between the column and pulling unit operative to resist their relative angular movement in the other direction.

JAMES H. MCCOLLOUGH.

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