65 on the body 62 projecting into a cap bore 66 spring means as for example a torsion spring 67 is connected between the cap and body to urge the body in one rotary direction in addition finger actuated means including a remote key as at 68 is operable to oppose the spring via a tension strand and displace the body 62 in the opposite rotary direction such means may include a driven pulley 69 integral with the body by means such as eccentric screw 69a a drive pulley drive roller 70 proximate the key a cord or line 71 wound on the driven pulley and drive pulley so that the two rotate together and a suitable means such as friction or rack type connection or as shown a cord 72 between a stem 68a on the key and the drive pulley so that the latter is rotated when the key is depressed suitable stop pins 73 and 74 may project into grooves 75 and 76 in the pulley to limit its rotation at locations corresponding to the above described modes of operation of the valve body to connect or not to connect the tubing section with the crooks such an actuation system with all forces transmitted in tension between keys and valves has the dual advantages of low inertia and accommodation of extreme dispersion of valves from the source of control observation of the key assembly shown in fig4 comprised of elements 68 68a 72 drive pulley guide roller 70.