Self-advancing device

Abstract

A device which includes an elongate body with a movable mass arranged for sliding movement within the body is disclosed. The element is arranged to decelerate toward an end of the body in order to impart forward movement thereto, via momentum transfer, and is further arranged to accelerate away from said end in order to further drive the body forward, again using momentum transfer.

1 . A device which includes an elongate body with a movable mass arranged for sliding movement within the body, the element being arranged to decelerate toward an end of the body in order to impart forward movement thereto, via momentum transfer, and being arranged to accelerate away from said end in order to further drive the body forward, again using momentum transfer. 
   
   
       2 . A device as claimed in  claim 1 , wherein the mass is a piston element. 
   
   
       3 . A device as claimed in  claim 2 , wherein the element is driven under action of a fluid and the device includes control means to allow fluid flow between the element and the body to be controlled so as to effect deceleration and acceleration of the element toward and away from the end of the body. 
   
   
       4 . A device as claimed in  claim 3 , wherein the device defines a first flow path for applying pressurised fluid to a rear of the element and a second flow path for allowing the fluid to be discharged from between a front of the element and the end of the body, wherein fluid flow along the second flow path is reduced as the element approaches the end of the body, in order to provide a fluid cushion to dampen impact between the element and the body. 
   
   
       5 . A device as claimed in  claim 4 , wherein a third flow path is provided to inject fluid between the element and the end of the body, in order to accelerate the element in a rearward direction relative to the end of the body, fluid flow along the third flow path being established when the element is adjacent the end of the body. 
   
   
       6 . A device as claimed in  claim 5 , wherein a sensor is provided to determine the proximity of the element relative to the end of the body. 
   
   
       7 . A device as claimed in  claim 5 , wherein the second flow path is provided in a conduit, which extends axially through the element and the body, and the third flow path is also through the conduit, in a reverse direction to the second flow path. 
   
   
       8 . A device as claimed in  claim 5 , wherein the element slides in a channel, within the body, and a conduit extends axially through the channel and the element, for providing pressurised fluid to the device, wherein valves are arranged in the conduit to direct the pressurised fluid into a region between a rear of the body and a rear of the element, along the first flow path, and to direct fluid from the conduit along the third flow path, into a second region, in front of the element, for driving the element in a reverse direction, and wherein the second flow path passes through openings formed in the channel and into a return passage formed in the body fluid to exit the second region along the second flow path, as the element is moved forward. 
   
   
       9 . A device as claimed in  claim 8 , wherein the valves include a main valve positioned in a forward end of the conduit and secondary valves arranged adjacent the first region, wherein a positive fluid pressure is maintained in the conduit and the valve is in a closed condition when the element travels in a forward direction, so that fluid is directed through the secondary valves, into the first region between the conduit and the body, to drive the element in the forward direction. 
   
   
       10 . A device as claimed in  claim 9 , wherein additional valves are provided to vent fluid captured between a rear end of the body and the element directly into the second flow path, when the element is moved rearward of the body. 
   
   
       11 . A device as claimed in  claim 10 , wherein the mass includes a plurality of piston elements. 
   
   
       12 . A device as claimed in  claim 11 , wherein the piston elements are in the form of balls. 
   
   
       13 . A self-advancing probe, including a device, as claimed in  claim 12 . 
   
   
       14 . A self-advancing probe, as claimed in  claim 13 , wherein the probe is provided with a light source and camera. 
   
   
       15 . A self-advancing probe, as claimed in  claim 14 , wherein the probe includes location means for securing the probe relative to adjoining structure. 
   
   
       16 . A self-advancing probe, as claimed in any one of  claims 15 , wherein the probe is an endoscope. 
   
   
       17 . A self-advancing probe, as claimed in  16 , wherein the endoscope is disposable. 
   
   
       18 . A method of generating movement in a self-advancing device which includes a body and a moveable mass arranged for sliding movement relative to the body, including rapidly decelerating the element toward an end of the body to impart forward movement thereto, via momentum transfer and accelerating the element away from said end in order to further drive the body forward, again using momentum transfer.