Inverted Dump Cylinder

Inverted, trunnion style, hydraulic dump cylinder.

Benefits

Lower maintenance and longer service life than an end pin style cylinder.

Dirt wiper seals are on the bottom side of each stage so dirt does not settle and build up over time in the cylinder. The extending stage and gravity tend to keep dirt cleaned off of the cylinder. Pin style cylinders tend to push through the dirt that is held on the cylinder and then work it into the cylinder during retraction.

The inverted cylinder lifts almost vertically through the entire extension eliminating sag and subsequent cylinder bearing wear that occurs with end pin style cylinders. Pin style cylinders typically lean from 30 degree forward at its closed position to 10 degree rearward at full extension.

The cylinder rod end shaft of Anvil is over four feet shorter than the end pin style. This shorter end shaft results in a shorter column and thus a stiffer and more stable column. This results in lower side loads and less lower bearing wear.

The inverted trunnion bearings are located far apart on each side of the cylinder body so the body is very stiff in the lateral direction compared to high clearance end pin style cylinders. This results in increased sideways cylinder stiffness that contributes to less bearing wear and increased lateral body stability.

The cylinder moves away from the body during dumping which results in greater cubic capacity for any length of body the trailer may have. This is because there no space taker for any cylinder intrusion into the body like pin style cylinders require. There is no need for a "dog house" or steeply sloped front bulkhead which takes capacity away from a trailer when a pin style cylinder is used. Without these intrusions the Anvil gains approximately 1 cubic yard more capacity by using the inverted trunnion style dump cylinder and not the end pin cylinder.

The inverted trunnion cylinder design also results in a longer effective bridge length for any length of trailer body. The vertical mounted hydraulic cylinder located out in front of the vertical bulkhead results in a king pin to tandem suspension length of approximately three feet longer than the same length body with an end pin cylinder and sloped front bulkhead or dog house. The additional three feet will increase gross weight and payload from 1,500 to 2,000 lbs. under Federal Formula B Highway Regulations.

The inverted trunnion cylinder design provides greater lift capacity for the same sized cylinder if using the pin style design. The cylinder lifts in nearly a vertical angle so the entire capacity of the cylinder is used to lift the body and the load. A pin cylinder mounted at the typical 30 angle loses about 15% of its capacity to a horizontal component which must be absorbed by the trailer structure.

The inverted trunnion design provides easier hydraulic cylinder maintenance. The vertical mounting of the cylinder has open top access and readily accessible and easy to remove externally mounted trunnion bearings and an independent rod end bearing shaft. This means that the cylinder can be easily disconnected and lifted straight out for repair or replacement and then easily reconnected. This can all be done all without effecting any other part of the trailer.