Hydraulic Hammer (redirected from Hoe ram)

Hydraulic Hammer 

a machine for working metal by blows from falling parts driven by fluid under high pressure. Hydraulic hammers are used for forging, closed-impression die forging, and sheet-metal stamping. They are similar in design to hammers utilizing other types of power—for example, steam hammers. Hydraulic hammers are not widely used because of the difficulty of controlling the impact force.

Table 1. Properties of some hydraulic fluids
	Viscosity at 50°C (m2 per sec)	Freezing point (°C)	Flash point (°C)
*At 100°C
Hydraulic oil for automatic lines of metal-cutting lathes...............	(25-35) × 10−6	-10	190
Oil for presses...............	1 × 10−7*	-15	200
Oil for hydraulic drives of GT-50 diesel locomotives...............	(11-14) × 10−6	-28	165
Oil for motor vehicle hydraulic systems hydromechanical transmissions...............	(3.5-4) × 10−6*	-45	160
torque converters and automatic gearboxes...............	(23-30) × 10−6	-40	175
power steering...............	(12-14) × 10−6	-45	163
Oil for high-load mechanisms (ESh)...............	20 × 10−6	-50	150
Shock-absorber fluid (AZh-12T)...............	12 × 10−6	-55	165
Hydraulic brake fluid (GTN oil)...............	1 × 10−7	-63	92
Alcohol-glycerine fluids SG...............	6.2 × 10−6	-50	28
SVG...............	2.5 × 10−6	-60	28
SVG-2...............	7.5 × 10−6	-50	30
Alcohol-castor oil fluids ESK...............	(8.2-8.6) × 10−6	-25	12
BSK...............	(9.6-13.8) × 10−4	-25	14