Wednesday, October 20, 2010

Rippers

Outstanding productivity
1. Superior ripping performance is achieved through a large operating weight, high engine output and a conventional drive undercarriage.
2. Large maximum penetration depth provides high ripper production.
3. The unique linkage design enables the ripper point to draw an ideal locus during cylinder tilting for effective excavation of embedded rocks. In the KOMATSU linkage, the lift cylinder is mounted on the beam, causing the point to make an ideal movement when the tilt cylinder is actuated. Thus, the range of digging angles practically available is wider than the conventional type range, giving excellent digging force.


Minimum downtime
1. Large sectional area of the beam extends service life.
2. The forged ripper points are sharpened for excellent penetration and long service life.

Easy operation
1. Optional pin puller facilitates change in digging depth.
The optional pin puller mechanism functions to insert or remove the pin from its hole. This is accomplished with a hydraulic cylinder and can be accomplished by an experienced operator, from within the cab. This feature thus provides a time savings benefit.


Specifications
Multi-shank Ripper (Rigid type)


* : Including additional oil weight, except D85A
** : Including the hydraulic control unit

Specifications
Multi-shank Ripper (Variable type)


Specifications
Giant Ripper (Variable type)


Ripper Selection
Multi-shank rippers (Rigid type)



Highly efficient ripping of soft rock is possible with three shanks. The parallelogram ripper linkage maintains the shanks at the optimum digging angle during operation, regardless of the shank's penetrating depth.

Multi-shank rippers (Variable type)



The ripper point angle can be varied hydraulically to suit the specific ground conditions. The ideal movement of ripper points ensures powerful digging force throughout the entire digging angle range.

Giant rippers (Variable type)



Specially made to handle hard rock with reinforced beam and a shank. The tilt angle of the ripper point is adjustable for better penetration and fragmentation.


1. COMPARISON BETWEEN THE MULTI-SHANK AND GIANT (SINGLE SHANK) RIPPERS


2. COMPARISON BETWEEN THE RIGID AND VARIABLE TYPE RIPPERS


Various types of ripper points are available, and the general standards for selection according to the type of use are given below.
1. Types of ripper points
Ripper points are categorized according to the following three items.


When combining of these categories, 4~7 types of points are available for each model.
2. Features of each type of point


If the point does not dig into the rock, but slips on the rock surface, the friction heat between the point and rock causes an extreme rise in temperature of the point, thus reducing point hardness. There is a close relationship between hardness and wear: The higher the hardness, the less the wear.

Also there is a close relationship between increased temperature of the point and excellent wear of the point (abnormal wear). The red point has superior heat resistance, it retains its hardness better than the yellow point
as the temperature increases. Thus , the red point is advantageous for hard rock applications, which is where extreme point temperatures are typically seen. The trade off is that due to the higher hardness of the point, it is more brittle, and thus more susceptible.


Not all material can be ripped. Whether or not a rock can be ripped can be determined by any of the following methods:
1) By the type of rock
2) By an indoor rock test
3) By a field rock test
4) By a digging test with the ripper in the field.

Method 4) is most effective. If the user has no experience in ripping, an actual ripping operation should be demonstrated for the user by an operator experienced in ripping. Methods 1) and 3) are described below :

Determination of rippability by type of rock
Rocks are classified into sedimentary (aqueous), igneous, and metamorphic. The following general rules apply:
1) Sedimentary rocks such as sandstone, limestone, and shale can be ripped easily. Sedimentary rocks are usually found stratified in layers which vary in thickness. The thinner the layers, the easier it is to rip them.
2) Igneous rocks such as granite, basalt, and andesite are not found in distinct layers or cleavage planes, and this makes them difficult to rip.
3) Metamorphic rocks such as gneiss, schist, and quartzite vary in rippability according to the degree of stratification or cleavage.
Rippability depends not only on the type of rock, but also on the degree of weathering or fracturing.
Characteristics which determine the ease of rippability are summarized below.



Determination of rippability by inthe- field rock test. 
Seismic wave velocity tests are used to estimate the rippability of rock. In this test, an artificial earthquake is introduced and the travel speeds of seismic waves through different kinds of sub-surface materials are measured. Thus the degree of consolidation, thickness of sub-surface layers, hardness, degree of fracturing, stratification, and weathering can be determined .

The chart below compares ripper performance to seismic velocities. It should be used ONLY A ROUGH GUIDE, because ripper performance is subject to many other conditions.

D155A Giant Ripper
D155AX Giant Ripper