TYPES AND USES - Continued
Illustrated below are some standard combinations of the
1. Jack pushing combinations
2. Jack pulling combinations.
3. Jack spreading combinations.
4. Jack clamping combinations
USING TRESTLES (Jack Stands)
Trestles are used to support a specified maximum
load (usually a vehicle). They are available in
various sizes and are designed to support only
stationary loads. The load force must remain
straight down the center axis (1).
Trestles are vertically
positioning the column (2) and inserting the pawl (3)
fully into a tooth of the rack located on the side of
Trestles should be inspected, for bends, poor or
separated welds, cracks, corrosion, misalignment of
the rack and pawl, or the pawl not seating fully in the
rack. They should be checked prior to use; small
abnormalities or defects can lead to a failure under
the stress of a load. Questionable trestles should
not be used.
20-4 Change 3