COUNTERBALANCE APPARATUS WITH TRANSVERSE PNEUMATIC SPRING AND BELLCRANK LINKAGE WITH IMPROVED PNEUMATIC SPRING STRUCTURE AND METHOD OF OPERATION

摘要

ABSTRACT OF THE DISCLOSUREA transversely mounted, single pneumatic spring, and dualbell crank and idler link assembly providing a compactcounterbalance for hinged closures such as automobile trunk lids.In an automobile trunk installation, the assembly is installedwith the spring in lateral disposition in the forward upperportion of the trunk, thus being effectively concealed.Alternative pneumatic spring enhancements, e.g., a multi-outputforce feature and a pressure decay compensation feature may beincorporated in the spring unit to enhance opening of the lid andto improve life expectancy of the pneumatic spring by minimizingand effectively negating pressure loss due to leakage of gas pastthe shaft seal. Excess spring cylinder length can provide spaceor volume zones used for the enhancement features Structurewhich provides a multiple output force for the pneumatic spring,utilizes positioning of the spring shaft end bushing and seal tovary the working volume by changing effective cross-section areaof the piston shaft near the end of a compression stroke. Theextra cylinder length enables a sealed partition wall to separateextra volume and the operative volume part of the cylinder. Theextra volume is filled with a supply of gas under higher pressurethan that of the spring operative gas pressure and, inconjunction with permeability characteristics of the spring shaftseal and the partition wall seal, enables compensation forleakage from the cylinder. Multiple force output provisions canbe used in a substantially vertically disposed spring, filledwith a predetermined quantity of oil, and used as a liquid-pneumatic shock absorber. A supplemental orifice type disc valveunit can be used in such a shock absorber, located near theclosed end of the spring cylinder.