Caterpillar Inc.

Joseph E Allen

Dean M Peterson

Robert A Lapke

The present invention includes a means of equalizing pressure within a sealed pin joint assembly. The pin joint assembly includes slidably connecting a pin through a bearing assembly fitted within a bore in an equalizer bar. The pin is circumferentially surrounded by a pair of seals disposed on either side of the bearing assembly for sealing within the equalizer bar. The seals are positioned adjacent the bearing assembly to define a pair of cavities therebetween. A receiving passage extends from a counterbore at an outer surface of the equalizer bar and terminates at the bearing assembly and is fluidly connected with the pin joint assembly. A grease zerk is disclosed within the receiving passage as a means to direct fluid into the joint wherein accumulation within the cavities is expected. As the pressure fluctuates within the cavities during operation, the lubricating fluid is free to travel through a pair of discharge passages and an interconnected cross passage therebetween.

Lubricated joint with equalizing pressure zone

The present invention includes a method of relieving pressure within a sealed pin joint assembly so that the seal is protected from excessive pressure. The pin joint assembly includes slidably connecting a pin through a bearing assembly fitted within a bore in an equalizer bar. The pin is circumferentially surrounded by a pair of seals disposed on either side of the bearing assembly for sealing within the equalizer bar. The seals are positioned adjacent the bearing assembly to define a pair of cavities therebetween. A receiving passage extends from a counterbore at an outer surface of the equalizer bar and terminates at the bearing assembly and is fluidly connected with the pin joint assembly. A grease zerk is disclosed within the receiving passage to direct fluid into the joint wherein accumulation within the cavities is expected. As the pressure increases within the cavities either during addition of the lubricating fluid or during operation, a relief valve disposed within a pair of discharge passages in close proximity to the seals opens to relieve the pressure within the cavities. The relief in pressure within the cavities protects the seals from damage or destruction.

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Brimfield, IL, United States of America

Joseph E Allen