Downhole depth measuring apparatus

Abstract

According to an aspect of an embodiment, provided is a downhole depth measuring apparatus. The downhole depth measuring apparatus comprises a frame, a cable reel rotatably supported upon the frame, a length of cable carried upon the cable reel, and a level wind assembly supported on the frame for level distribution of the cable on the cable reel during retrieval of the cable. The level wind assembly is operably coupled to a stationary counter assembly.

1 . A downhole depth measuring apparatus, comprising,
 a frame;   a cable reel rotatably supported upon the frame;   a length of cable carried upon the cable reel;   a level wind assembly supported on the frame for level distribution of the cable on the cable reel during retrieval of the cable;   wherein the level wind assembly is operably coupled to a stationary counter assembly.   
     
     
         2 . The apparatus according to  claim 1 , wherein the level wind assembly includes a cable count assembly supported upon a plurality of cross rods spanning between a support bracket extending from the frame, and an opposing winder plate, the cable count assembly being reversibly laterally moveable between a first position proximal the support bracket, and a second position proximal the winder plate. 
     
     
         3 . The apparatus according to  claim 2 , wherein the cable count assembly is provided with a slide element at each point of contact with the plurality of cross rods. 
     
     
         4 . The apparatus according to  claim 3 , wherein the slide elements are provided in the form of a linear bearing. 
     
     
         5 . The apparatus according to  claim 2 , wherein the cable count assembly includes a follower configured to cooperate with a rotatable shaft mounted between the support bracket and the winder plate, the follower having a follower blade that engages a set of reversely extending spiral grooves provided on the rotatable shaft, therein directing the cable count assembly to move laterally relative thereto. 
     
     
         6 . The apparatus according to  claim 5 , wherein the rotatable shaft is rotationally linked to the cable reel through the intermediate driving action of an endless belt member interconnecting a shaft sprocket provided on the cable shaft, and a reel sprocket provided on the cable reel. 
     
     
         7 . The apparatus according to  claim 2 , wherein the level wind assembly includes a rotatable rail extending between the support bracket and the winder plate, the rotatable rail being configured at one end to be coupled to the stationary counter assembly, and further being configured along its length to support a cable count wheel forming part of the cable count assembly, wherein the cable count wheel is mounted upon the rotatable rail in a manner that permits for a fixed relative rotation of the cable count wheel relative to the rotatable rail, yet permitting lateral movement relative thereto. 
     
     
         8 . The apparatus according to  claim 7 , wherein the rotatable rail is configured with at least one planar bearing surface which engages a corresponding slide element provided on the cable count wheel, therein establishing the fixed relative rotation of the cable count wheel relative to the rail. 
     
     
         9 . The apparatus according to  claim 8 , wherein the rotatable rail is configured with three planar bearing surfaces, and wherein the slide element corresponding to each planar bearing surface is presented in the form of a bearing. 
     
     
         10 . The apparatus according to  claim 9 , wherein each bearing presents a roller surface that engages a respective bearing surface on the rotatable rail. 
     
     
         11 . The apparatus according to  claim 1 , wherein the counter assembly is provided in the form of a rotary encoder. 
     
     
         12 . The apparatus according to  claim 11 , wherein the rotary encoder is provided in the form of an optical rotary encoder.