Blake Crushers

Blake Crushers

Blake Crushers are Jaw Crushers with a movable jaw pivoted at the top, giving greatest movement to the smallest lumps. The throw of Blake jaw crushers is determined by the hardness of the ore as well as the size of the machine. It may vary from d in for hard but friable ores to 3 in for resilient material.

Types

Single-toggle jaw crushers

In this type of crusher the swing jaw is suspended on the eccentric shaft, which allows a lighter, more compact design than with the double-toggle machine. The motion of the swing jaw also differs from that of the double-toggle design. Not only does the swing jaw move towards the fixed jaw. under the action of the toggle plate, but it also moves vertically as the eccentric rotates. This elliptical jaw motion assists in pushing rock through the crushing chamber. The single-toggle machine therefore has a somewhat higher capacity than the double-toggle machine of the same gape. The eccentric movement, however, increases the rate of wear on the jaw plates. Direct attachment of the swing jaw to the eccentric imposes a high degree of strain on the drive shaft, and so maintenance costs tend to be higher than with the double-toggle machine.

Double-toggle Blake crushers

In this model, the oscillating movement of the swinging jaw is effected by vertical movement of the pitman. This moves up and down under the influence of the eccentric. The back toggle plate causes the pitman to move sideways as it is pushed upward. This motion is transferred to the front toggle plate and this in turn causes the swing jaw to close on the fixed jaw. Similarly, downward movement of the pitman allows the swing jaw to open.

Features

• It is the oldest crushing machinery in use i.e. from 1858
• The movable jaw is hinged at the top so that maximum amplitude of motion is at the bottom of the crushing face
• It consists of two pitman & two toggles width of discharge opening varies
• The stresses developed are even
• Hence can be made in large Sizes