Pipes and tubular conduits – Combined – With end structure
Reexamination Certificate
1998-06-11
2001-09-11
Hook, James (Department: 3752)
Pipes and tubular conduits
Combined
With end structure
C138S125000, C138S126000, C138S132000, C138S172000
Reexamination Certificate
active
06286555
ABSTRACT:
The present invention relates to a roll-back tube construction, preferably for an endoscopy apparatus, a catheter or another shaft-like circular appliance for examining channel-shaped cavities, for example in the human body, or for inserting operating instruments, medicaments, etc., and in particular a roll-back tube construction in accordance with the preamble of Patent claim
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.
Endoscopes are mainly used for visually examining the esophagus, the stomach, the intestine (from the mouth or from the anus), the urethra and the bladder. For this purpose, the endoscope is equipped at its distal end with a lighting device and with an optic, preferably a camera chip, which is connected via leads inside an endoscope shaft to a camera control means at the end of the endoscope shaft. The camera control means is in turn connected via a video processor to an external monitor on which an operating physician can identify the areas to be examined. The distal end of the shaft to be introduced into the cavity is here designed so that it can be bent in any direction, and it can be angled, much like a finger, manually by means of a handle, preferably via two control wheels with brake at the rear end section of the endoscope. In addition, the endoscope shaft generally has at least two channels passing through it, which open out at the distal end. When so required, these channels can be used for passing though cleaning fluid, for example, in order to clean an area which is to be examined, or CO
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(air) for opening out the cavity or else various working instruments can be pushed through a working channel, for example forceps or scissors for removing tissue specimens, biopsy needles or heatable cutting wires, which can likewise be manually operated at the rear end of the endoscope shaft via operating wires or Bowden cables inside the inner channel.
The endoscope generally has an elongate tubular shape, with a diameter of about 9 to 15 mm, and consists of a bendable material so as to be able to follow the curvatures of the cavity which is to be examined, for example intestinal loops.
An endoscope of this generic type is known from the prior art, for example in accordance with DE 4,242,291 A1.
This endoscope essentially consists of an endoscope head or distal end, which is adjoined by an endoscope shaft consisting of a flexible bendable tubular body, and an operating mechanism at the rear end of the endoscope shaft. Moreover, in a rear end section of the endoscope there is provided a first drive or advance mechanism which exerts a driving force on the endoscope shaft via drive wheels. Arranged around the endoscope shaft, at least in its front section, there is a roll-back tube which is driven by a second drive or advance mechanism. The roll-back tube here consists of an inner tube section which bears slidably on the jacket surface of the endoscope shaft and is turned back in the area of the distal end of the endoscope to form a front outer tube section. The front outer tube section is also guided back as far as a second drive mechanism and fixed to the housing thereof. In the rear area of the endoscope, the inner tube section is turned back to form a rear outer tube section, which is likewise guided back to the second drive mechanism and fixed to the housing thereof, on the axial end side of the housing opposite the front outer tube section.
The second drive mechanism here acts on the inner roll-back tube section in order to move the latter in the axial direction of the endoscope shaft. For this purpose, the second drive mechanism has a type of cuff or collar which can be contracted in the radial direction and thus pressed with friction onto the inner tube section and can also be moved in the axial direction of the endoscope in the manner of a piston. In a further variant of this second drive mechanism, there are a number of friction wheels which bear on the inner tube section and thus exert an essentially continuous advance movement on the inner tube section. The radially acting pressing forces of the cuff or of the friction wheels of the second drive mechanism are here chosen to be so great that at least some of the applied pressing forces are transmitted, by a material deformation of the inner tube section, to the jacket surface of the endoscope shaft, so that the endoscope shaft is driven forwards together with the inner tube section despite the relative slidability.
Since, with this type of drive alone, effected by the second drive mechanism, i.e. without the first drive mechanism, the speed of advance of the roll-back tube at its front roll-back area would, because of its roll-back movement, be only half as great as that of the endoscope shaft, i.e. the endoscope shaft would, with increasing depth of penetration, emerge telescopically from the roll-back tube into the cavity, the first drive mechanism, mentioned in the introduction, exerts a braking force on the endoscope shaft, which braking force counteracts the advancing force of the second drive mechanism.
The second drive mechanism is in this case synchronized with the first drive mechanism in such a way that, in the interaction of the two drive mechanisms, the speed of movement of the inner tube section in an axial direction is approximately twice as great as the speed of movement of the endoscope shaft, this sliding relative to the inner endoscope shaft (i.e. the distal end of the endoscope shaft moves at the same speed as the front turn-back area of the roll-back tube).
In order to facilitate the relative movement between the endoscope shaft and the roll-back tube, the prior art according to DE 4,242,291 A1 further provides a lubricating device by means of which a lubricant can be forced into a gap between the inner tube section and the endoscope shaft and also into a cavity between the inner and outer tube section. For this purpose, the lubricating device has, inter alia, a cone-shaped sleeve which is slipped over the endoscope shaft and interacts sealingly with the rear roll-back area of the roll-back tube, which rides up onto the cone-shaped sleeve. The lubricant, which is forced by means of a pump into a gap between the cone-shaped sleeve and the endoscope shaft, spreads out between the inner tube section and the endoscope shaft along the entire length of the roll-back tube, and excess amounts of lubricant in the front turn-back area of the roll-back tube emerge into the cavity which is to be examined.
According to an inhouse prior art, the inventor also has in development an endoscopy apparatus which uses a double roll-back tube system of the above generic type, as is described in brief hereinbelow:
This endoscopy apparatus has an endoscope shaft which is guided slidably in a tube which is rolled back at both ends and which can once again be moved by a drive mechanism which acts on the inner tube section of the roll-back tube. The drive mechanism has at least one continuous advancing means, in particular friction wheels, which can press radially on the inner tube section in order to move the latter essentially continuously in the axial direction of the shaft. The great advantage of this is that the continuous advance of the roll-back tube system can be exactly controlled and thus, for example, the distal end of the endoscope can be guided to the exact location.
It is provided here that the pressing force of the advancing means on the inner tube section is chosen such that the shaft is in direct frictional contact with the inner tube section, at least in the area of the advancing means. The advancing means is made up of one or more friction wheels which are prestressed against the inner tube section with a predetermined or adjustable pressing force, so that it is possible to ensure that the endoscope shaft is advanced into the cavity to be examined within a patient in a movement which is on the one hand continuous and on the other hand as slip-free as possible.
In addition, the drive mechanism has a device for synchronizing the shaft movement with the movement of the roll-back tube. This can be a rear and front end-piece or clampi
Pauker Fritz
Pauker Robert
Viebach Thomas
Weiglhofer Gerhard
Graybeal Jackson Haley LLP
Hook James
STM Medizintechnik Starnberg GmbH
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