Abstract:
A ring seal for protecting a designated area from ambient contamination is alternately placeable into its sealing and non-sealing positions. The ring seal permits a limited travel between the sealable surfaces without compromising the seal integrity. The ring seal facilitates an interference-free installation and selective maintenance of the sealable parts.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention pertains to grease seals and more particularly to an elastomeric ring seal facilitating an interference-free installation and maintenance of the parts and areas subject to sealing. 
     2. Information Disclosure Statement 
     The subject invention pertains to a seal which can be placed in its sealing position at will. This is particularly important for the sealable parts which must be assembled and thereafter maintained without interference of permanently embedded seals. 
     A below described embodiment exemplifies an application of the seal to a tracctor axle, which must be attached to an axle support called a bolster. The axle is restrained from moving fore-and-aft by means of thrust washers at both the front and rear of the bolster. The axle pivot bushings and thrust surfaces are lubricated by means of periodic greasing. The life of these elements is greatly increased if contamination by environmental pollution such as dust and moisture can be kept out. Conventional lip seals used at the thrust surfaces cannot be employed, because they interfere with an axle installation and enable keeping both thrust surfaces on the bolster and on thrust washers sealed. The novel seal is intended to keep dust and moisture out and grease in. Also the subject seal is of purgeable design which allows grease to flush out under the seal during the greasing operation, thereby flushing out any contamination that may have entered into pivot bushing or thrust surfaces. 
     SUMMARY OF THE INVENTION 
     According to the present invention, a ring seal for protecting a designated area from ambient contamination is alternately placeable in first and second positions. The ring seal is mounted in the vicinity of the designated area and bares this area in the first position and covers it in the second position. The retaining means for keeping said seal in either position are disposed near the designated area. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partially cross-sectional side view of a ring seal assembly mounted on a vehicle axis. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The invention may be carried into practice in a number of ways but one specific embodiment will be described by way of example only. 
     Referring now to FIG. 1, there is shown a vehicle bolster 8 supporting an axle 10, which can be a shaft or any other tubular member, having a differential 12. The axle 10 has its ends 14 and 16 journalled in two vehicle bolster bearings 18. The axle ends 14 and 16 have a similar diameter than the axle 10 so as to form a transition shoulder 17 at each axle end. The ends 14 and 16 are supported by the bolster half-bearings 20 and 22 coupled with the lower half-bearings or caps 24 and 26, respectively, by bolts 28. A steel bushing 30 separates the axle 10 from the bearing 18. A lip seal 32 mounted on the outer edge of the axle end 14 in a bearing annular rabbet 33 insulates the bearing 18 from the entry of dirt and moisture from the bearing outer side 35a. The thrust washer 34 abuts the shoulder 17, which is located close to the bearing inside surface 35b and limits the axle travel between the bearings 18 after the installation of the axle 10 into the bearings 18. 
     A peripheral circumferential groove 36 running in the axle 10 is disposed near each thrust washer 34. An elastomeric ring seal 38 shaped as a flat washer has a free-standing outer edge 40 and an inner edge 42 inserted into the groove 36. The outer edge 40 of the ring seal 38 is forced to contract by virtue of the rubber-like material compressing the ring toward the axle 10, thus giving the seal a concave or bottomless dish configuration. Prior to the upward mounting of the shaft or axle 10 into the upper half-bearing 20 or 22, the ring seal 38 can be flipped over and away from the bearing 18. In this position the outer edge 40 of the seal 38 rests against the shoulder 17 or differential 12, or any other upright standing part, if any. It must be understood that the seal can operate even without such a supporting part. Both seals 38 are facing each other in this axle pre-assembly or maintenance position. After the axle installation is completed, i.e., the caps 24 and 26 are already attached to the upper half-bearings 20, 22 by bolts 28, the ring seals 38 can be flipped over toward the bearings 18 until the outer edge thereof rests against the inside surface 35b of the bearing 18. In this position the ring seal 38 covers the area of contact between the bearing 18 and the axle 10, as well as between the thrust surface of the washer 34 and bearing inside surface 35b, thereby protecting them from an undesirable environmental contamination and entry of any foreign matter into the grease-full space between the axle 10 and the bearing 18. 
     The afore-described novel ring seal, which is simply a flat washer-shaped piece of elastomeric material, provides a number of important advantages, such as a facile mounting and dismounting from the shaft, extremely low cost of manufacturing, repair and replacement, an assembly time reduction, etc. One of the most important features of the invention is the ability of providing an interference-free installation of the shaft into the bearing means, which would be impossible to achieve with a conventional lip seal design. 
     The novel seal mounts into an axle groove and flips out of the way for an installation or maintenance of the axle into the bolster bearing. When the axle is placed into bolster boster bearing and after lower half-bearing caps are attached to the upper bolster bearing, the seal is flipped into its normal running position. 
     The seal allows the grease to be flushed out from under the seal during the greasing operation. The seal&#39;s ability to restore its original sealing position permits a flush-out of any contamination that may have entered into the bushings or thrust surfaces. Also, this permits to do away with precise manufacturing tolerances and allows a certain longitudinal axial travel of the axle in the bearing without compromising the integrity of the seal. No tools or other parts are needed for the seal alternate positioning, because it is biased to seal the designated area of protection by virtue of the elastomeric quality of the material itself. 
     While one embodiment of the invention has been illustrated as described herein, various changes and modifications may be made therein without departing from the spirit of the invention as defined by the scope of the appended claims.