allowed to be engaged with the first slot 113 through the first mounting hole thereby disallowing the first pusher 110 to be pulled out or allowing the second protruding key 131 to be engaged with the second slot 121 through the second mounting hole thereby disallowing the second pusher 120 to be pulled out additionally a preferred embodiment of the present invention allows the first feed tube 11 and the second feed tube 12 to respectively have different sizes of inside diameters thereby allowing the first pusher 110 and the second pusher 120 to be able to extend only into the first feed tube 11 and the second feed tube 12 respectively thus avoiding operating error also referring to fig4 in the case that the present invention is used as a juicer a filter mesh is first installed to the rear of the container of the machine body 20 and then the juicer shredder 230 is directly installed to the drive shaft 22 at this time the upper portion 111 and the lower portion 112 of the first pusher 110 are integrated in becoming one long pusher and the user needs to turn the safety switch 13 to allow the second protruding key 131 to engage with the second slot 121 of the second pusher 120 thereby making the first pusher 110 extending into the first feed tube 11 only after the first protruding key 130 is moved out from the inside diameter of the first feed tube 11 thus to push the vegetables and fruit for extracting the juice also referring to fig5 in the case that the present invention is used as a shredder the filter mesh and the juicer.