M Series Clamp-On Impact (Hammer Blow) Actuator

Manually operated valves can be difficult to open and close under certain conditions. The valve may stick, freeze, or be used so rarely that its internal parts become fused.  Additionally,  it can often be difficult to operate large valves when using a standard chain wheel.  To provide a solution to these problems, Roto Hammer® offers the M Series Hammer Blow Impact Actuator. The Hammer Blow mimics the motion of a hammer striking an anvil,  delivering a quick, measured blow that will free up a sticky valve without damaging its internal or external parts.

  • Ideal for overhead valves that tend to stick or are otherwise difficult to operate
  • Available in chain model (for operation above ground level) or hand wheel model (for ground level operation)
  • Either style (chain or hand model) may be ordered for Clamp-On or Direct-Mount installation
  • Direct-mount models are furnished with an adapter plate that replaces the existing hand wheel. This plate can be supplied blank or machined to fit the valve. If fitted, dimensional information is required.
Model No. For Use With Valve Hand Wheel Diameter Weight Chain Size Additional Chain Needed for Loop Chain Weight Per m. RCK Safety Cable Kit
M9 CMCO-DI 178 mm – 248 mm
(7”- 9 ¾” )
11.34 kg
(25 lbs)
1/0 610 mm
(2 ft.)
0.253 kg
(0.56 lbs)
RCK 3/16
M12 CMCO-DI 254 mm – 324 mm
(10” – 12 ¾”)
23.13 kg
(51 lbs)
1/0 914 mm
(3 ft.)
0.253 kg
(0.56 lbs)
RCK 3/16
M15 CMCO-DI 330 mm – 425 mm
(13” – 16 ¾”)
30.39 kg
(67 lbs)
4/0 1219 mm
(4 ft.)
0.461 kg
(1.02 lbs)
RCK 1/4
M18 CMCO-DI 432 mm – 495 mm
(17” – 19 ½”)
40.37 kg
(89 lbs)
4/0 1219 mm
(4 ft.)
0.461 kg
(1.02 lbs)
RCK 1/4
M24 CMCO-DI 508 mm – 635 mm
(20” – 25”)
62.60 kg
(138 lbs)
5/0 1829 mm
(6 ft.)
0.521 kg
(1.15 lbs)
RCK 5/16

M Series Clamp On (M9, M12, M15, M18, M24) Installation Instructions PDF – View | Download
M Series Clamp On (M9, M12, M15, M18, M24) Technical Drawings PDF – View | Download


Chain wheel MUST be installed properly for safe operation. Follow ALL Installation instructions carefully.
NEVER install an M-Series Impact Operation on ANY make, model or type of GEAR OPERATED valve.
To eliminate any possibility of the valve handwheel retaining nut backing off the stem, IT MUST HAVE A SET SCREW IN PLACE.
EVERY Impact Operator must be scheduled for REGULAR, PERIODIC inspection and maintenance.
Roto Hammer STRONGLY RECOMMENDS that EVERY overhead Impact Operator be fitted with a Roto Hammer Retaining Cable (available from H & N Supplies).
Set screws and other threaded fasteners MUST be secure and tight.