US2719396A

US2719396A - Rotary power lawn mower with lateral discharge

Info

Publication number: US2719396A
Application number: US301262A
Authority: US
Inventors: Curtis T Morris; Thomas E Coners
Original assignee: Outboard Marine & Manufacturing Co
Current assignee: Lawn Boy Inc
Priority date: 1952-07-28
Filing date: 1952-07-28
Publication date: 1955-10-04
Anticipated expiration: 1972-10-04

Description

c. T. MORRIS L-:T AL

ROTARY POWER LAWN MOWER WITH LTERL DISCHARGE Filed July 28, 1952 3 Sheets-Sheet l Caer/5 7T Maele/5 7740/14/95 E. CsA/@.95

ML,MML

A T roze NE V5 Um.. 4, 1,955 C. T. MORRIS ET AL Zfw RGTARY POWER LAWN MOWER WITH LATERAL DISCHARGE Filed July 28, 1952 3 Sheets-Sheet 2 lllllll llllll IULIII Illlll I 4 INVENTORS MGT/5 7.' Mae/5 BY '717/001145 .5. oA/5,95

A T roe/VE V5 C. T. MORRIS ET AL ROTARY POWER LAWN MOWER WITH LATERAL DISCHARGE Filed July 28, 1952 3 Sheets-Sheet 3 INVENTOR5 y/ 60,6775 7.A Maele/5 United States Patent ina RUTARY PWER LAWN MWER WITH LATERAL DISCHARGE Curtis T. Morris and Thomas E. Cnners, Lamar, Mo., assignors, by mesne assignments, to Gutboard, Marine 81; Manufacturing Company, Waukegan, Ill., a corporation of Delaware Application July 28, 1952, Serial No. 301,262

9 Claims. (Cl. 56--25.4)

This invention relates to a rotary power lawn mower with lateral discharge.

The teaching of the art has been to keep the grass clippings within the cutter housing of a rotary mower to cause them to be struck again and again by the blades with a View to thorough comminution. The present invention is based upon my discovery of the unexpected fact that the power absorbed by repeated action of the blades upon the clippings is far out of proportion to any result achieved and I am able, by lifting the clippings out of contact with the growing grass and immediately discharging the clippings from the mower housing, to effect power savings of 30 to 50%. For example, actual tests of a .9 H. P. power engine on a mower having an eighteen inch cutting blade and a lateral discharge opening from its forward side show better grass clipping results than were formerly accomplished with the same cutting blade using 11/2 H. P.

To achieve these results, the motor base and blade housing are so formed as to provide an upwardly convex channel of progressively increasing height which starts near one side of the housing forwardly of the cutter axis and continues upwardly and laterally to provide a laterally directed opening at the side toward which the forward part of the blade turns in operation. In the device disclosed, in which blade rotation is clockwise, the channel starts at the front left portion of the housing and discharges to the right, as viewed toward the direction of housing advance. The cut grass is raised and ejected in the same semi-circular traverse of the blade in which it is cut.

Substantially all of the grass cutting is done in the 180 degrees of cutter rotation which lies forwardly of the axis of rotation. This is true in any rotary mower, but in the present mower the axis of rotation is desirably slightly tilted so that the path of travel of the blade is slightly lower in this forward sector than in the sector behind the axis, whereby the blade is removed from frictional contact with the growing grass from which the tips have already been cut. The cut tips are thereby swept continuously to the side and out of the housing without repeated contact with the blade and even without the forward tilting of the axis of rotation, the lateral discharge alone is sufficient to affect the power economies above described.

A further feature of the invention consists of the arrangement whereby the housing has a cavity which accommodates the engine muller, the muer discharging into the laterally opening channel through which the grass clippings are moving laterally, the arrangement being such that the muffler blast is commingled with, and dissipated by, the clippings and gives up its energy to the clippings, to promote their flow and to reduce its own noise.

In the drawings:

Fig. 1 is a view in right side elevation of a mower embodying the invention.

Fig. 2 is a view of the mower on enlarged scale in longitudinal section, substantially along the line 2 2 in Fig. 3.

Fig. 3 is an enlarged plan view of the mower shown in Fig. 1.

Fig. 4 is an inverted plan view of the mower.

Fig. 5 is a view of the mower in front elevation, portions of the housing being broken away and shown in section to expose the mufller discharge.

Fig. 6 is a detailed View on the line 6--6 of Fig. 3.

Fig. 7 is a plan view of a modified embodiment of the invention, the motor being removed to expose the frame housing in plan.

Fig. 8 is an inverted plan view of the embodiment shown in Fig. 7, portions of the muffler being broken away.

Fig. 9 is a view in front elevation of the embodiment shown in Figs. 7 and 8, portions of the frame housing being broken away.

A casting 7 provides a frame and motor base. It has a central opening at 8 through which projects the lower crank shaft bearing 9 and the shaft 10 upon which the blade assembly 11 is mounted for rotation. At several points about the central opening 8 there :are seats 13, 14 for the motor, the motor crank case 15 including

arms

16, 17 which rest upon these seats. The seat 14 may optionally comprise a slightly elevated boss in order that the crank shaft axis may be slightly tilted upwardly and forwardly so that the path of travel of the blades is slightly lower forwardly of the axis than rearwardly thereof. This is shown in Fig. 2 by comparison of the blade tip 110 with blade tip 111.

The engine has an air cooled cylinder which projects forwardly at 18, a spark plug 19 provided with current by a fly wheel magneto 20, and a carburetor 21 supplied with fuel from a tank 22. The whole engine is unitary and is assembled on the frame base 7 simply by bolting the

arms

16 and 17 to the seats 13, 14.

F orwardly of the seats 13 the frame base has a further aperture at 24 through which projects a box like muffler 25 which is in unitary connection with the engine and supported entirely therefrom. Exhaust. gases escape from the mufer through the discharge port 26 which is illustrated in Figs. 4 and 5 and discharges into the inverted grass flow channel hereinafter to be described.

The propelling and guiding handle 27 is pivoted to

brackets

28 and 29 mounted on the upper surface of frame base 7 near the rear thereof as shown in Figs. 2 and 3.

The frame base 7 has a downwardly turned margin at 30 which is nearly continuous, as is clearly shown in Fig. 4. To the generally parallel portions 31 of the downwardly turned marginal flange 30 are bolted the

axle studs

32, 33 for the

rear wheels

34, 35. To the generally parallel and somewhat more widely separated

portions

36, 37, of the downwardly turned flange 30, are bolted the

axle studs

38, 39 of the

forward wheels

40, 41, these being somewhat more widely spaced apart than the rearward wheels. Transversely of the housing and frame base '7, at the forward end of the housing, there is a finished surface at 43 to which is bolted a comb plate 44 having depending teeth 45 through which the grass tips pass into the path of the rotating cutter blade tips and 111.

Commencing between the fore and aft center line of the cutter housing and frame base 7, and the left hand side thereof, as viewed toward the direction of advance, the housing is formed to provide an upwardly convex channel 50 which, as clearly shown in Figs. 2 and 5, is of progressively increasing height, terminating at its maximum elevation in the delivery port 51. The top of this port is materially above the level of the

wheels

40 and 34, as is clearly evident in Figs. 1, 2, and 5.

At the rear side of the inverted channel, the casting which forms the housing and base plate 7 includes a flange at 54 which delineates the rear wall of the clipping discharge passage leading to port 51. This wall, which clearly appears in Figs. 2, 4, and 5, assures the movechannel.

3 ment of the grass clippings laterally and outwardly from the housing, and tends to Apreclude the possibility that any of such clippings will pass rearwardly to whirl about the housing with the blades. We believe that most of the `grass clippings have but a single 4contact with the blade, that being at the `instant Vof severance from the growing grass, after which the clippings tend to move upwardly and laterally along .the wall `of the inverted `channel to the point of discharge. Their lateral movement is zassisted `by the .outward ilow of .air set in motion by the blades and centrifugally discharged through the It is yalso expedited by the intermittent blast of exhaust 5gasses which .opens into the channel from muffler `2.5. Incidentally, this arrangement -substantially :completely -relieves the operator of the exhaust fumes by which he has heretofore been annoyed. The noise of the .exhaust .is also minimized.

.Instead of the clippings being discharged in rows upon .the lawn, Las usually happens when they are deposited from `a conventional housing, the lclippings .discharged -through the .port 51 are very widely dissipated and do not form any discernible windrow. It will be observed that the wider spacing of the front vwheels and the result- .ant rearward inclination of the discharge -port in this embodiment causes .the clippings to be hurled somewhat rearwardly, as well as laterally.

vAs a .guard against possible injury to the loperator Vor ,to bystanders, Vone `or more bafes 55 desirably span the discharge port 51 and are desirably set at a slight upward inclination as shown in Figs. 1 and 6 to assure the ,upward vand youtward projection of the clippings, while offering Amaximum protection against contact with the knives.

In the modified embodiment shown -in Figs. 7, 8, and 9, the frame housing 70 is quite similar to that above described but the wheels have a different arrangement in order that the clipping discharge channel 500 may open directly `to .the side instead rearwardly as in the previously described embodiment. It will be observed in Fig. 9 that the inverted channel 500 commences immediately adjacent the left lfront wheel 410 and continues nearly rectilinearly to the discharge port 510, there being but a slight forward convexity at 501 to clear the path of the blade 11. The teeth 45, along the front of the channel, serve :as guard teeth while admitting the Ygrass to the path of the blade just as previously described in the embodiment of Figs. 1 to 5. The rear wall of the channel comprises a rectilinear flange S40 which may be cast integrally with the base frame 70. At its inner end flange 540 merges with .the mufer 250, likewise desirably -cast integrally with the base frame and covered by a covervplate v251. The muffler is vented through a verticalrow of ports 260 which are desirably bored through the 4casting to direct the exhaust gases longitudinally ,of the 4channel 50d. The front wall of the muffler may be curved `in conformity with the front wall portion 501 of the channel.

Fig. 7 shows a manifold fitting 252 having an exhaust pipe 254 opening downwardly from the engine into the mufer 250. .As in the previously described embodiment, the engine 18 is mounted on a spider 17 which is bolted at three points to the frame casting 7l).

Instead of lhaving the channel 500 at right angles to the path of movement of the mower, it may be directed slightly forwardly in order to provide an optimum location for the .right front wheel 460. lt has been found that there is an advantage in the staggered wheel aropening slot at 311 in its side flange 310. This slot is located outside the path of travel of the wheel 410 and it will be observed in Fig. 8 that the radius of the path of travel of the blade 11 is greater than the lateral distance of the slot from the cutter axis. Accordingly, the provision of this slot is a great aid in trimming. It enables the mower to be operated at no greater distance from a tree or building or stake or other obstructions than the thickness of the ange 310. Grass growing in immediate proximity to such an obstruction enters the slot into the path of the blade and is immediately cut.

As in the previously described device, the clippings are discharged from the base housing in the same sweep of the blade by which they are severed vand without any movement circumferentially of the housing. It is important that such clippings are elevated from the uncut grass of the lawn and immediately discharged.

`Ejection of the clippings is promoted by a strong blast of air set in motion by the blades and discharged tangentially vfrom .the base housing. We have found improved results in establishment of such ablast when the housing is spanned by an integral flange 312 substantially `concentric with the axis of the cutter, .such flange merging lat its ends with the side flange 31() and being `approximately equal thereto in vertical height.

We claim:

l. A motor base and blade housing for a rotary mower blade, said housing comprising a top wall integrally provided at its forward end with a traversely extending inverted channel opening laterally at the side of the housing toward which the mower rotates in traversing the front of the housing, said channel being approximately at rightangles to the direction .of travel, the front wheel at the side to which the `channel opens being behind the channel, and the front wheel at the other side projecting ahead of the channel whereby said wheels are offset to the front and rear of a transverse line through the housing.

2. A motor base and blade housing for a rotary mower blade, Vsaid housing comprising a top wall integrally provided at its .forward end with a transversely extending vinverted channel opening laterally at the side ofthe housing toward which the mower rotates in `traversing the front of the housing, said channel opening being provided with baille means comprises atleast one baffle plate extending fore and `aft across said opening and having a laterally upward inclination.

3. A rotary mower comprising the combination with a generally .upright power shaft and sickle blade means mounted thereon for rotation on a generally horizontal path, lof a downwardly open housing provided with front and rear wheels and enclosing the path of sickle blade rotation, said housing comprising a depending skirt with a lateral opening from said housing at .the forward end thereof and at the side toward which said sickle blade means rotates in the forward portion of its path, ,the other side vof -the housing having ,a lateral projection with a forwardly opening slot immediately ahead of a portion of the path ofsaid blade means in which said .blade means is moving forwardly.

4. The ,device of claim 3 in which said housing comprises inits ,top wall an inverted channel having a lateral extension past' said skirt at said opening for discharge of blade cuttings fromgrass entering said housing lthrough said slot.

5. The device .of claim 4 in which -the housing wall portion comprising said .channel kis extended .downwardly at the rear yof -said channel for Aguiding said kclippings through said opening.

6. In a rotary mower, the combination lwith a generally upright power shaft and sickle `blades mounted thereon for cutting grass, of a housing comprisinga top walland depending skirtenclosing the path `of Vsickle 4blade `rotation, said housing having in .said top wall an `inverted channel and said skirt having .an opening `through which said channel opens in a forward portion of the housing and at the side thereof toward which said blades rotate, and an engine in operative connection with said shaft and having exhaust means with a discharge port opening into said channel in the general direction of grass clipping discharge therethrough.

7. The mower of claim 6 in which the exhaust means comprises side and top wall portions integral with the housing, together with a bottom closure plate fitting such portions and attached to the housing.

8. The device of claim 6 in further combination with wheels connected with said housing for the support thereof, said engine being mounted on said housing to receive support thereby from said wheels, the housing having an opening through which said engine exhaust means bodily projects, and said housing being provided with a flange depending from its top wall and extending at the rear of said channel from said exhaust means to the lateral opening aforesaid.

9. The device of claim 6 in which said housing comprises a relatively wide portion forwardly of said lateral opening and a relatively narrow portion rearwardly thereof, and forward and rearward wheels having axle studs connected with the housing at the relatively wider and narrower portions aforesaid.

References Cited in the le of this patent UNITED STATES PATENTS 1,588,745 Kear et al. June 15, 1926 1,899,564 Frey Feb. 28, 1933 2,071,872 Cockburn Feb. 23, 1937 2,491,544 Arkenberg Dec. 20, 1949 2,504,416 Hlernan Apr. 18, 1950 2,531,081 Shippey Nov. 21, 1950 2,559,897 Phelps July 10, 1951 2,675,661 Titzer Apr. 20, 1954