US 4,058,178 AGranted

Hydraulic cylinder unit

AssigneeTadano Ironworks Co., Ltd.

InventorsShinitsu Shinohara, Hisanori Uchino, Hiroyuki Yamaji

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Abstract

A hydraulic cylinder unit which comprises a cylinder, a piston slidably inserted in the cylinder in a fluid-tight manner, and a piston rod connected to the piston at one end thereof and projected outwardly from the cylinder and which is operated to extend the piston rod by a fluid supplied under pressure into one chamber in the cylinder and to retract the piston rod by a mechanical force applied to the piston or piston rod (single-acting type) or by a fluid supplied under pressure into the other chamber in the cylinder (double-acting type) is used for lifting, transporting or displacing a material in various industries. In the use of such hydraulic cylinder unit, load in the axial direction of the unit is applied to the cylinder unit by a load or material carried on operated by the cylinder unit or the piston rod thereof and detection of such load is often required. This load is detected by a strain gauge mounted in the piston rod.

Claims6

Dependent claims

In a hydraulic cylinder unit comprising:

a. a cylinder means pivotally connected to a base;
b. a piston axially slidably inserted in the cylinder means in a fluid-tight manner between a retracted position and a fully extended position, said piston being extended by hydraulic pressure supplied to said cylinder means;
and
c. a rigid piston rod means connected to the piston at base end thereof and projected outwardly from the cylinder means, the piston rod means being connected to a load which is to be carried by the cylinder unit, load-detecting means for detecting load applied to the cylinder unit in the axial direction of the cylinder unit which means is arranged within a hollow space provided in said rigid piston rod means and is mounted on one of the components of said piston rod means which component is strained by a load carried by the cylinder unit as the piston moves between the retracted and fully extended positions, the load-detecting means including at least one gauge for detecting strain of said component, the load-detecting means providing an electrical output signal corresponding to the load in response to strain detected by the gauge.

1 more element

Dependencies are inferred from the claim text.