Boat-detaching hook (Brown & Level’s)
Boat-detaching hook (Brown & Level’s). The upright standard is secured to the boat, and the tongue hinged to its upper end enters an eye in the level which works on a fulcrum at the middle of the standard. A similar apparatus is applied at each end of the boat. The hooks of the tackles hook into the tongues, which are secure until it is desired to detach the boat, when a rope attached to the lower end of each lever is pulled in such a direction as to slip the eye at the upper end of the lever from off the tongue, which being then liberated slips out of the hook of the tackle and detaches the boat.
Only the input is driven; every other part of this model moves by physics (MuJoCo), and its ratios are measured. Run it live, change its parameters, or switch the friction off to see the output stop.
- Modelled as
- Seen from the side, as Brown, gravity on. The upright standard is screwed into the boat (a 5 kg ballast with a strip of gunwale), which hangs from it and can only move up and down. The tongue is hinged at the standard's head and lies out and down to the left through the bight of the tackle's hook; the hook, its swivel and the block above are fixed. The boat's weight draws the hinge down against the bight, so the tongue's tip tries to rise: the eye at the upper end of the lever, which turns on a fulcrum at the middle of the standard, lies over the tip and holds it down. The only input is the rope on the lever's lower end being pulled - the lever turned at a slow steady rate. The fulcrum is placed so the eye slides straight out along the tongue.
- Measured
- The boat hangs still (about 1 mm of give) while the eye slides out along the tongue; when it leaves the tip (lever turned about 0.2 rad) the tongue swings up past upright, slips out of the hook, and the boat drops away clear of the tackle onto the water (a stop 6 cm below).
- Notes
- One end of the boat is shown; the boat is a ballast weight on a vertical slide rather than a hull hung at both ends, the water is a stop 6 cm below, and the rope's pull is a steady turning of the lever.
Film (MP4) · Still (PNG) · Spec (YAML) · Model (MJCF)
