Abstract: A drill rig assembly adapted to be mounted on a vehicle and having a pivotal link assembly mounted to the vehicle. Attached in slidable relationship to the link assembly is a mast assembly containing feed means and rotary means fully enclosed within the mast assembly. An electronic level within the mast assembly automatically maintains the mast assembly in a predetermined, angular position. The drill rig assembly is capable of drilling either vertically or at selected, incremental angles. The drill rig assembly is designed to be safe in operation and lightweight, while providing performance characteristics of larger drill rigs.

Abstract: A rock breaking device adapted to be coupled to the lifting arms of a tractor or similar vehicle is disclosed, the device having an upstanding guide tube with a hammer, chisel, and anvil disposed therein. The hammer can be raised within the guide tube by frictional engagement with a drive member and is then allowed to fall by gravitational force to impact the chisel and/or the chisel and anvil, thereby driving the chisel into the surface to be broken. The device has a shock absorber to minimize the force of impact and as a safety feature, cannot be made operational until actually positioned on the surface to be broken.

Abstract: The customary side hand propulsion ring adjacent to each main wheel of a manual wheelchair is mounted through a lost motion connection between the propulsion ring and main wheel so that the propulsion ring can have limited rotational movement relative to the main wheel. A friction brake drum or partial drum fixed to the wheelchair frame inside of the main wheel is engaged by at least one of a plurality of circumferentially spaced over center friction locking devices pivotally held on the main wheel. Each over center friction locking device is moved by a release element to a non-locking position relative to the drum or partial drum in response to reverse movement of the propulsion ring by a chair occupant. Economy and ease of operation are provided for. The wheelchair occupant need not remove his or her hand from the propulsion ring when operating the anti-rollback mechanism.