Endoscope shaft made of a composite tube
Inventors
Dillinger, Ilona Sabine • Grosshardt, Manfred Josef
Assignees
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Publication Number
US-8608646-B2
Publication Date
2013-12-17
Expiration Date
Abstract
An endoscope shaft made of a composite tube comprises an external tube and an internal tube which is softer and more resilient compared to the external tube as well as a helical spring for stiffening the composite tube. According to the invention, the helical spring in the relaxed state has an outer diameter which is larger than the inner diameter of the internal tube. Furthermore the helical spring is inserted in the internal tube preferably loosely at a spring bias, whereby it is radially pressed against the internal tube.
Core Innovation
The invention relates to an endoscope shaft having a composite tube with an external tube and an internal tube, where the internal tube is at least one of softer and more resilient than the external tube. The composite tube is stiffened by a helical spring mounted within the internal tube and adapted to radially press against the internal tube. This composite tube configuration is used together with an everting tube drive in which an endoscope shaft is guided to slide in the drive tube and forms a radial counter bearing for drive means that are in frictional engagement with the drive tube.
The helical spring is configured with windings and an outer diameter such that, in a relaxed state, the outer diameter is larger than an inner diameter of the internal tube. The spring exerts a radially outwardly directed pressing force against a radially inner surface of the internal tube. The pressing force is sufficiently high that the helical spring windings impress a structure corresponding to the spring windings to a radially outer surface of the external tube through the walls of the internal tube and the external tube.
To reduce frictional interaction during an everting tube drive, the disclosed structure includes spiral-like or helical features that correspond to the spring windings, including a spring-winding embossing/rib pattern on the outside of the external tube and spiral-like grooves/helical elevations and indentations. The helical groove structure reduces contact area and forms lubricant pockets to lower friction with an everting tube drive, supporting improved counter-bearing behavior of the shaft relative to the drive means.
Claims Coverage
The independent claim provides coverage of an endoscope with an everting tube drive and a guided endoscope shaft that forms a radial counter bearing for frictional drive means, where the shaft includes a composite tube stiffened by a helical spring sized to emboss a windings-corresponding structure onto the external tube through the internal tube wall.
Endoscope with everting tube drive and radial counter bearing shaft
An endoscope comprising an everting tube drive consisting of a drive tube everted twice encompassed by a drive device including drive means in frictional engagement with the drive tube to apply a feed force, and an endoscope shaft guided to slide in the drive tube and forming a radial counter bearing for the drive means.
Composite tube with softer internal tube and helical spring stiffening
The endoscope shaft comprises a composite tube including an external tube having a wall and an internal tube having a wall that is at least one of softer and more resilient than the external tube, and a helical spring mounted within the internal tube and adapted to radially press against the internal tube for stiffening the composite tube.
Spring-sized relaxed-state radially outward pressing embossing structure
The helical spring has windings and an outer diameter such that, in a relaxed state, the outer diameter is larger than an inner diameter of the internal tube, the helical spring exerts a radially outwardly directed pressing force against a radially inner surface of the internal tube, and the radial pressing force is sufficiently high that the helical spring windings impress a structure corresponding to the spring windings to a radially outer surface of the external tube through the walls of the internal tube and the external tube.
Overall, the claim coverage centers on combining an everting-tube-drive endoscope with a guided shaft that serves as a radial counter bearing, where a helical spring sized for relaxed-state radial expansion stiffens a softer internal tube and embosses a spring-winding-corresponding structure onto an outer surface of the external tube through the composite tube walls.
Stated Advantages
Improved counter-bearing behavior.
Reduced friction with an everting tube drive.
Documented Applications
Everting-tube endoscope drives including drive device concepts such as double everting tube, friction-wheel/crawler drive, and feed-force transmission.
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