slot 90 having wider and narrower portions the individual steps of the step surfaces 92 94 define angular stop positions or tilt settings along the rotational path of movement of the tilt housing 16 the wide portions being tilt positions and the narrower portions separating tilt positions a tip 96 of the pin 84 is shaped to correspond to the shape of the individual steps of the step surfaces of 92 94 in the exemplary embodiment of the invention the tip 96 is rectangularly shaped and the individual steps of the step surfaces 92 94 defined rectangular openings referring now to fig5 and 8 the pin 84 is moved between the locked position and the unlocked position by the lever 86 the pin 84 includes a cam follower portion 98 and the lever includes a cam portion 100 in the exemplary embodiment of the invention the cam follower portion 98 includes a slot 102 and the cam portion 100 includes a pin 104 the pin 104 pierces the slot 102 and moves the cam follower portion 98 in response to rotation of the lever 86 as best seen in fig8 the lever 86 is rotatable between a locked position designated at 106 and an unlocked position designated at 108 when the lever 86 is at the locked position 106 the tip 96 is positioned in the slot 90 when the lever 86 is at the unlocked position 108 the tip 96 is retracted from the slot 90 a retaining ring 110 can be affixed to a distal end of the pin 104 to prevent the pin 104 from moving out of the slot 102 referring.