Multi-gear-ratio portal gear box

A method for changing a transmission ratio of a gear box, the method comprising:

• providing a removable adaptor;
• providing a housing that defines an input gear indent, an output gear indent, and an idler-gear indent, wherein the input gear indent is configured to receive an input shaft, wherein the output gear indent is configured to receive an output shaft and wherein the idler-gear indent is configured to receive the removable adaptor;
• providing an input gear that is configured to be connected to the input shaft;
• providing an output gear that is configured to be connected to the output shaft;
• providing an idler gear that is configured to be connected to the removable adaptor positioned within the idler-gear indent defining a first position of the idler gear, wherein, in the first position, the idler gear is configured to transfer power between the input gear positioned on the input shaft and the output gear positioned on the output shaft;
• removing at least one of the input gear and/or the output gear;
• replacing the at least one removed gear with a different gear;
• moving the removable adaptor to move the idler gear to a second position, wherein, in the second position, the idler gear is configured to transfer power between the gear on the input shaft and the gear on the output shaft, wherein a transmission ratio between the input shaft and the output shaft with the idler gear in the first position is different than with the idler gear in the second position.

A kit for providing a gear box with an adjustable transmission ratio, the kit comprising:

• a housing defining an input gear indent, an output gear indent, and an idler-gear indent, wherein the input gear indent is configured to receive an input shaft, and wherein the output gear indent is configured to receive an output shaft;
• a first input gear connectable to the input shaft;
• a first output gear connectable to the output shaft;
• a removable adaptor selectively positionable in more than one configuration within the idler-gear indent;
• and
• a first idler gear connectable to the removable adaptor;
• wherein changing the position of the removable adaptor within the idler-gear indent changes a position of the idler gear relative to the input shaft and output shaft, thereby permitting use of input and output gears with different diameters or swapping the position of gears to alter a transmission ratio between the input shaft and the output shaft.