Rippers

• Construction, mining and quarrying
• Cost varying form material to material to be ripped
• Hard rock
• Compared with drilling, blasting
• Life of ripping tips as well as shortening of undercarriage should be considered.

Characteristic of the material to be ripped influence the selection of ripper type:

• Number of shank required
• Ripping speed
• Amount of ripper penetration

Ripper types

• Various type rippers are used in the dozers
  • Towed units – cable operated
  • Integrated units – hydraulic operated
  • Backrippers – mounted on frame of the dozer – high duty
• Intergral rippers two types
  • Hinge type
  • Parallelogram type

• Tip can be replaced, it protects shank and adopter from damage.
• When adopter is damaged, next shorter tip so as to reduce the load on the adopter.
• Protector provides the support to the tip and wear protection to the adopter
• When protector worn out to 6mm
• Protector failure – adopter damage

Ripper classification

• Fixed multiple shank ripper
• Variable multiple shank ripper
• Fixed giant ripper
• Variable giant ripper

• Fixed multiple shank ripper -simple ripping operation
  • Shank moves – up & down
  • Digging depth adjustable
• Fixed Giant ripper: single powerful shank
  • not common compare to variable giant ripper
• Variable multiple shank ripper: change the angle
  • used where there are many boulders or quality of rock not constant
• The variable giant ripper: single powerful shank
  • Angle of ripper changed according to ground requirements

Ripping efficiency

• When material is broken, loosen the surface in one direction, then cross ripping should be adopted
• If material is soft use multiple rippers
• Ripping should be downhill
• Avoid reversing when shank is in ground
• When both dozing and ripping operations are required to be done, it should rip going out and doze on the way in
• Shank tip should be sharp
• Use a low gear range

• When the track start slipping, ripper and shank should be raised
• For the hard material use shorter tip, for a ordinary work use longest and sharpest point
• Do not uncover the unripped portion of the rock during dozing of the material loosened by ripping.

Rippability

• It has been established that rippability of most the rocks are related to the speed at which the sound wave travels through the rock.
• Sound travels faster in a dense medium i.e. the greater the speed the greater is the hardness of material.
• The speed of sound can be determined by the ‘refraction’ seismograph.
• Thus rocks which propagate sound waves at low velocities are rippable, while rocks which propagate waves at high velocities are not rippable.
• Marginal rocks – blasting or drilling – correct size of ripper and capacity of tractor
• Cost of earth excavation, without rock is very less as compared to excavating a rock by ripping.
• life of undercarriage components will be shortened
• These factors need be considered while determining the ripping cost.