Patent attributes
An apparatus includes a roller assembly including a roller frame and ground-contacting roller rotatably coupled with the roller frame. A suspension assembly includes a compressible suspension member operatively coupled with the roller assembly. A flexible rigging assembly includes an upper flexible rigging member and a lower flexible rigging member operatively coupled with the suspension assembly. The flexible rigging assembly is adjustable between a first state in which the upper flexible rigging member is taut and the lower flexible rigging member has a non-zero amount of upper flexible rigging member slack and a second state in which the lower flexible rigging member is taut and the upper flexible rigging member has a non-zero amount of lower flexible rigging member slack.