This document specifies a method for the evaluation of the buckling load which:

a) takes into account a geometric model of the hydraulic cylinder, meaning it does not treat the hydraulic cylinder as an equivalent column,

b) can be used for all types of cylinder mounting and rod end connection specified in Table 2,

c) includes a factor of safety, k, to be set by the person performing the calculations and reported with the results of the calculations,

d) takes into account possible off-axis loading,

e) takes into account the weight of the hydraulic cylinder, meaning it does not neglect all transverse loads applied on the hydraulic cylinder,

f) can be implemented as a simple computer program, and

g) considers the cylinder fully extended.

The method specified is based on the elastic buckling theory and is applicable to single and double acting cylinders that conform to ISO 6020 (all parts), ISO 6022 and ISO 10762. If necessary, finite element analyses can be used to verify as well as to determine the buckling load.

The method is not developed for thin-walled cylinders, double-rods or plunger cylinders.

The method is not developed for internal (rod) buckling.

The friction of spherical bearings is not taken into account.

NOTE       This method is based mainly on original work by Fred Hoblit^[2]. This method has been established in reference to the standard NFPA/T3.6.37^[1].

a) takes into account a geometric model of the hydraulic cylinder, meaning it does not treat the hydraulic cylinder as an equivalent column,

b) can be used for all types of cylinder mounting and rod end connection specified in Table 2,

c) includes a factor of safety, k, to be set by the person performing the calculations and reported with the results of the calculations,

d) takes into account possible off-axis loading,

e) takes into account the weight of the hydraulic cylinder, meaning it does not neglect all transverse loads applied on the hydraulic cylinder,

f) can be implemented as a simple computer program, and

g) considers the cylinder fully extended.

The method specified is based on the elastic buckling theory and is applicable to single and double acting cylinders that conform to ISO 6020 (all parts), ISO 6022 and ISO 10762. If necessary, finite element analyses can be used to verify as well as to determine the buckling load.

The method is not developed for thin-walled cylinders, double-rods or plunger cylinders.

The method is not developed for internal (rod) buckling.

The friction of spherical bearings is not taken into account.

NOTE This method is based mainly on original work by Fred Hoblit.[2] This method has been established in reference to the standard NF PA/T3.6.37.[1]

ISO/TR 16806:2003 describes how to present the rating information in technical documentation for application by a user.

The clevises are used on piston rods of pneumatic cylinders for mechanically transmitting the cylinder force. The design of the clevises is based on the maximum forces resulting from the specified internal diameter of the cylinders and pressure according to ISO 6432, ISO 15552 and ISO 21287.

1 1 bar = 100 kPa = 105 Pa; 1 Pa = 1 N/m2.

The spherical bearing end eyes are used on piston rods of pneumatic cylinders for mechanically transmitting the cylinder force under oscillatory rotational and tilting movements. The design of the rod-end spherical eyes is based on the maximum forces resulting from the specified internal diameter of the cylinders and pressure according to ISO 6430, ISO 6432 and ISO 15552.

The clevises are used on piston rods of pneumatic cylinders for mechanically transmitting the cylinder force. The design of the clevises is based on the maximum forces resulting from the specified internal diameter of the cylinders and pressure according to ISO 6430, ISO 6432 and ISO 15552.

Les tenons à rotule taraudés d'extrémité de tige sont utilisés sur les tiges de piston de vérins pneumatiques pour transmettre l'énergie mécanique développée par le vérin sous forme de mouvements oscillatoires de rotation ou de bascule. La conception des tenons à rotule taraudés d'extrémité de tige repose sur les forces maximales résultant du diamètre intérieur spécifié des vérins et de la pression conformément à l'ISO 6432, l'ISO 15552 et à l'ISO 21287.

[1] 1 bar = 100 kPa = 105 Pa; 1 Pa = 1 N/m².