The Strength of Jacks in Compression: Methods Suitable for Determining the Compressive Strength of Jacks Which May Be Locked Internally or Externally

THE strength criterion for hydraulic and pneumatic jacks usually occurs under compression and the methods for determining this strength and the critical load from stability considerations depend largely upon the construction of the jack and the operating conditions in which the load is applied. Suitable methods for use in particular cases are indicated below and for this purpose jacks may be divided into two classes according to the operating conditions, viz.: