the frames may be bridged by a rigid arch alternatively they may be braced by a strut acting between the ripper assembly and the tractor frame if this latter arrangement is used the ripper assemblies are preferably hinged to the blade arms to permit full normal blade movement a ripper made according to the present teaching is especially useful when operating on uneven or debris covered ground it does not tend to rake up debris and thus does not require time and fuel for clearing the teeth because of the location of the teeth the prime mover is easier to steer and a rip of more uniform depth can be maintained application_number US 45252882 A description fig1 illustrates a conventional soil ripper using a parallel arm control linkage ripper assembly 2 is attached to a crawler type tractor 4 the ripper consists of a base frame 6 carrying vertical frame members 8 and upstanding ears 10 the frame is attached to the prime mover by a series of heavy bolts 11 a lower parallel arm member 12 is pivotally attached to frame member 8 at 20 near the point of attachment of the ripper frame to the prime mover an upper parallel arm member 14 is similarly pivotally attached to frame member 8 at 18 the vertical links 16 complete the parallelogram these are pivotally attached to the upper parallel arms at.