HAND KNOBS AND LEVERS

Packaging machines use lots of hand knobs and hand levers to facilitate adjustment. To some extent I find them incorrectly used.

Hand levers and knobs eliminate the need for tools. Hand knobs are symmetrical. They can be rounded, triangular or polygonal. Some, like wing nuts, have two tabs. Hand levers are asymmetrical with a single horizontal or angled arm to the side.

When I improve changeover I frequently replace nuts and bolts (requiring tools) with knobs and levers. I do this systematically. If the fastener normally requires complete removal, I use a knob, if it only requires loosening, I use a lever. If this concept can be applied consistently, it provides a memory aid to the operator or technician. This prevents the unnecessary removal of a fastener that only needs loosening and vice-versa. It is also preferable ergonomically.

I believe that knobs and levers are used too much as well as too little. One of my goals is always elimination of tools in changeover. Anywhere there is a nut or bolt, I replace it with a knob, lever or other toolless fastener. Some exceptions are necessary for safety reasons. On the other hand, anything that is not to be routinely adjusted or removed should require a tool. It may be possible to adjust only one side rail of a conveyor. If so, that side should have hand levers. The other, non-adjusted side, should have setscrews or bolts requiring a tool. This helps prevent unnecessary adjustment.

Finally, in keeping with my philosophy of making everything as visible as possible, I recommend that when using knobs and levers, they should be safety orange to make them stand out.