Abstract:
A self-propelled farm machine includes a rotatable air inlet screen assembly having a rotatable member and a surrounding contact surface with a positive seal therebetween. The preferred seal is composed of flexible, resilient material and includes a body portion circumscribing the rotatable member and in sealing engagement therewith, a disk-shaped skirt circumscribing the body portion and flexed into wiping engagement with the contact surface, and a transition section therebetween.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of self-propelled farm machines of the type having a rotatable air inlet screen assembly. More particularly, the invention is concerned with a seal apparatus for providing a positive seal between the rotatable member of the screen assembly and a surrounding contact surface. 
     2. Description of the Prior Art 
     During the operation of farm machines such as tractors and self-propelled harvesters, air-borne debris may be induced onto the engine radiator thereby affecting its cooling capacity. To correct this, the prior art discloses rotating air inlet screen assemblies that filter debris from the radiator air stream. 
     There has been a problem, however, in providing a seal between the rotating member and the body of the machine. One prior art solution has been to provide outward air flow in the area between the rotating member and the vehicle body. Another solution has been to provide brushes in this area. These solutions, however, do not provide a positive air seal between the rotating member and the farm machine body. 
     SUMMARY OF THE INVENTION 
     The present invention solves the prior art problems discussed above and provides a distinct advance in the state of the art. In particular, the seal apparatus hereof provides a positive air seal between the rotating member of a rotating screen assembly and a surrounding contact surface of the farm machine body. 
     The preferred seal apparatus includes a body portion with sufficient length to circumscribe the rotatable member of the screen assembly, a skirt extending along the length of the body portion, and a transition section therebetween. In combination with a farm machine, the seal apparatus circumscribes the rotatable member and is clamped in place with the ends abutting one another. The inboard surface of the body portion engages and provides a positive seal with the rotatable member. In forming the body portion about the rotatable member, the skirt flexes into wiping engagement with a surrounding contact surface and provides a positive seal therewith. Other preferred aspects of the invention are disclosed herein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of the preferred seal apparatus in accordance with the present invention shown in combination with a farm machine; 
     FIG. 2 is a partial exploded view of the rotatable air inlet assembly of FIG. 1; 
     FIG. 3 is a cross-sectional view of the preferred seal apparatus before installation on a farm machine; 
     FIG. 4 is a partial sectional view of the screen assembly of FIG. 1; and 
     FIG. 5 is a partial pictorial view of the preferred seal apparatus illustrating the joining of the ends. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 illustrates preferred seal apparatus 10 in combination with a farm machine 12 such as a tractor in accordance with the present invention. In pertinent part, machine 12 includes engine 14, radiator 16, radiator fan 18, screen assembly 20, and air inlet housing 22 which channels inlet air as induced by the operation of fan 18 through assembly 20 and radiator 16. 
     As shown in FIG. 2, screen assembly 20 includes rotatable member 24, tubular side screen 26, top screen 28 and cleaning assembly 30. Seal apparatus 10 is positioned between side screen 26 and rotatable member 24 as discussed further herein. 
     Rotatable member 24 is preferably in the nature of a bicycle wheel rotatably mounted in a corresponding opening 32 defined in top wall 34 of housing 22. Rotation blades 36 are positioned in the spokes of member 24. Radiator fan 18 induces air flow downwardly through member 24 and across blades 36 which causes rotation of member 24 and thereby rotation of screen assembly 20. 
     As best shown in FIG. 4, the periphery of rotatable member 24 includes spaced, outwardly extending, wheel rims 38a and 38b, and spaced ledges 40a and 40b extending inwardly from rims 38a,b respectively and recessed from the outer edges thereof. 
     Cleaning assembly 30 is conventional in nature and includes baffle 42 and vacuum nozzle 44 connected to the area between radiator 16 and fan 18. This induces a partial vacuum in nozzle 44 during operation. Baffle 42 is positioned adjacent the interior faces of screens 26,28 and prevents air flow through the adjacent portions thereof. This releases debris from the outer faces of these portions for removal by nozzle 44. 
     Top wall 34 of housing 22 includes a contact surface in the nature of an annular, stainless steel wearplate 46 surrounding opening 32 and thereby surrounding rotatable member 24. 
     Referring to FIGS. 3-5, seal apparatus 10 is preferably an extruded construct composed of 60 durometer EPDM rubber presenting a length sufficient to circumscribe rotatable member 24, although other materials may be utilized to form the seal apparatus 10, such as polyurethane or a relatively harder rubber. FIG. 3 illustrates apparatus 10 in profile before installation about rotatable member 24. Seal apparatus 10 integrally includes body portion 48, planar skirt 50 extending along the length of body portion 48, and transition section 52 therebetween. 
     Body portion 48 presents inboard surface 54, outboard surface 56 and includes upper portion 58 and lower portion 60. Upper portion 58 presents upper inboard surface 62, and lower portion 60 presents lower inboard surface 64. Surfaces 62, 64 are sloped in order to conform to the slopes of ledges 40a,b respectively as shown in FIG. 4. Upper portion 58 also includes upstanding bead 66 and lower surface 68. 
     Transition section 52 extends outwardly and downwardly from lower portion 60 of body portion 48 as viewed in FIGS. 3 and 4. Transition section 52 presents shelf 70 and inboard face 72. 
     Skirt 50 extends outwardly from the lower area of transition section 52 at an angle of about 5° below horizontal as viewed in FIG. 3, that is, at an angle of about 95° relative to outboard surface 56 of body portion 48. 
     Referring to FIG. 4, apparatus 10 is installed by inserting body portion 48 between rims 38a,b until upper and lower inboard surfaces 62, 64 engage and thereby seal against ledges 40a,b respectively. In this position, bead 66 engages and seals with the interior of rim 38a and lower surface 68 engages and seals with the interior of rim 38b. Also, inboard face 72 of transition section 52 engages and seals with the periphery of rim 38b. In this way, a positive seal is achieved between seal body portion 48 and rotatable member 24. 
     As illustrated in FIG. 5, seal apparatus 10 presents opposed ends 74a and 74b. At end 74a, body portion 48, transition section 52 and a portion of skirt 50 are cut to present skirt flap 76. During installation around rotatable member 24, ends 74a,b are abutted with skirt flap 76 overlapping and adhered to that portion of skirt 50 adjacent end 74b, as illustrated by the phantom lines in FIG. 5. 
     During the installation process, skirt 50 flexes toward and into contact with wearplate 46 to present an angle between about 15° and 20° below horizontal as viewed in FIG. 4, that is, between about 105° and 110° relative to outboard surface 56. This flexing occurs because the circumference of skirt 50 is greater than that of body portion 48 when formed into a ring about rotatable member 24. The configuration and composition of seal apparatus as described herein are such that lower face 78 of skirt 50 engages wearplate 46 sufficiently to provide a positive seal during rotation without any significant effect on the rotation of screen assembly 20. 
     Next, side screen 26 is slipped over seal apparatus 10 against outboard surface 56 until the lower edge of side screen 26 rests on shelf 70 as shown in FIG. 4. Hose clamp 80 is then installed and tightened about side screen 26 opposite outboard surface 56 and top screen 28 attached to side screen 26. 
     With engine 14 operating, radiator fan 18 induces air flow downwardly through screens 26, 28, through rotatable member 24 and through radiator 16. The air movement over blades 36 induces rotation of rotatable member 24 and thereby screen assembly 20. With seal apparatus 10 in place, the wiping engagement between skirt 50 and wearplate 46 allows rotation of screen assembly 20 while providing a positive seal thereby avoiding the problems of the prior art. 
     Those skilled in the art will appreciate that the present invention encompasses many variations in the preferred embodiment described herein.