new query. 6999. rock crushers. (a) every rock crusher where an employee is required or permitted to be at, or near, an unguarded feed opening, shall be provided with adequate means whereby the power can be quickly disconnected in case of emergency. such means of disconnecting the power shall be located at the crusher feed opening.,ford rock crusher 4 speed,ford rock crusher 4 speed products. as a leading global manufacturer of crushing, grinding and mining equipments, we offer advanced, reasonable solutions for any size-reduction requirements including, ford rock crusher 4 speed, quarry, aggregate, and different kinds of minerals.