The Boler Company

Timothy V Hess

Phillippi R Pierce

Joseph M Ross

Marc A Gibson

An air-free, relatively lightweight lift assembly for an axle/suspension system of a highway/rail convertible semi-trailer, utilizes a transversely-oriented coil torsion spring having a relatively low spring rate. The torsion spring is captured between a stationary plate and a rotatable plate. A flexible link is pivotally attached at its upper end to the rotatable plate and at its lower end to the axle. This assembly results in a variable rate moment arm and continuously increasing leverage when the suspension air spring is overinflated to lower the system for transfer of the trailer from a highway tractor to a rail bogie, thus enabling use of a less robust air spring. The assembly conversely creates a decrease in leverage at the lifted rail transport position, to securely maintain the axle/suspension system in the rail position. For highway use, the lift assembly provides suspension damping without shock absorbers.

Highway/rail trailer axle/suspension lift assembly

A locking mechanism for a movable subframe of a semi-trailer includes at least a pair of transversely spaced pins. Each pin is extendable into and retractable from an opening formed in its respective longitudinally extending main member of the subframe and a selected aligned one of a plurality of openings formed in its respective longitudinally extending rail of the trailer main frame. An elastomeric bladder is disposed between the pins and is operatively connected to one or more cables and/or linkage members which in turn are operatively connected to the pins. When the bladder is voided of air and is in its collapsed state, sufficient slack exists in the bladder, cables and/or linkage members to enable the bias force of a coil spring disposed about each of the pins to independently cause the pins to extend through their respective aligned openings to lock the subframe in a selected longitudinal position with respect to the trailer main frame. When air is introduced into the bladder, it distends or elongates and in turn shortens the length of the portions of the bladder, cables and/or linkage members which are in transverse alignment with the pins, to impart a linear retraction force on the pins which overcomes the bias force of the springs to independently retract each of the pins from its respective main frame opening enabling repositioning of the subframe beneath the trailer frame. The subframe is free of additional structure for bearing reactive forces generated during normal operation of the locking mechanism.

Locking mechanism for movable subframe of semi-trailers

A movable subframe or slider for a semi-trailer is modified to provide a storage bay between the slider and semi-trailer for accommodating a walk ramp and its carrier hardware. A reinforced elongated spacer cap is mounted on the uppermost surface of each main member and associated cross members of the slider. The spaced-apart parallel caps provide sufficient clearance between the bottom surface of the trailer body and the uppermost surface of the slider cross members, for mounting a walk ramp and its carrier hardware on the underside of the trailer body. The pins and coil springs of the retractable locking pin mechanism of the slider are relocated upwardly into the spacers. Rail guides and low frictions strips also are relocated from the slider main members to the spacer caps. This relocation enables the modified slider to be mounted on standard body rails of a semi-trailer, which are mounted on and depend from the underside of the trailer body. The modified slider thus can be efficiently retrofitted on semi-trailers adding a walk ramp but having a prior art slider and standard body rails, merely by replacing the prior art slider with the modified slider, and can also be used on newly manufactured semi-trailers incorporating a walk ramp.

Ramp-accommodating movable subframe for a semi-trailer

A movable subframe for tractor-trailers, commonly referred to as a slider, includes an improved retractable pin mechanism for locking the movable subframe in a selected position relative to the tractor-trailer body. A manually operated handle is used to pneumatically actuate the pin mechanism, or in the event that the mechanism is unable to be pneumatically actuated, to manually actuate the pin mechanism. Conversion between the pneumatic and manual actuation modes is accomplished without modification to the retractable pin mechanism. More specifically, a handle assembly, which in the pneumatic mode operates generally independent of the other parts of the pin mechanism, is manually moved from a starting position in which the pins are in an extended locked position, to a first position to engage a button valve thereby opening the valve to supply air to an air chamber, which in turn causes pneumatic actuation and retraction of the pin mechanism. Alternatively, the handle assembly can be moved directly from the starting position to a second position, bypassing the first position and the pneumatic mode, whereby the handle assembly operates integrally with the other parts of the pin mechanism, which in turn causes manual actuation and retraction of the pin mechanism.

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Smithville, OH, United States of America

Timothy V Hess