| 摘要 |
<p>A safety system (1) comprises right and left tethers (1, 2), one on either side of a drawbar (3) and a PTO shaft (4) of a tractor (100) pulling in this example a slurry spreader (110). The tethers (1, 2) are connected to PTO switches (10) having sockets (11) for engaging ends of the tethers (1, 2). The switches (10) form part of the electrical circuit of the tractor, located at a position in the circuit so that when open power to the PTO is immediately cut off. In order to do any work in and around the PTO shaft (4) the operator leans in over a tether (1, 2). However, if the operator trips or falls towards the PTO shaft (4), or if loose clothing is pulled by the shaft, movement of the person against the tether 1 or 2 causes the tether to pull out of the relevant switch (10). Disconnection of a switch (10) immediately causes the control system to kill power to the shaft (4). The sensitivity of the switches, and/or the tautness (degree of coiling and mechanical properties of the material) of the tethers are chosen to suit the circumstances.</p> |
