US3717071A

US3717071A - Rope feed piston assembly

Info

Publication number: US3717071A
Application number: US00042789A
Authority: US
Inventors: J Gordon
Original assignee: Individual
Current assignee: Sullivan Machinery Co
Priority date: 1970-06-02
Filing date: 1970-06-02
Publication date: 1973-02-20
Anticipated expiration: 1990-02-20

Abstract

A FEED CABLE PISTON ASSEMBLY AND MORE PARTICULARLY MEANS FOR KEEPING THE FEED CABLE RELATIVELY FREED FROM DIRT BUILD-UP AND MEAND FOR SECURING THE CABLE TO DRIVING PISTON HEAD.

Description

J. E. GORDON 2 Sheets-Sheet 1 INVENTOI? JOHN E. GORDON Feb. 20, 1973 ROPE FEED PISTON ASSEMBLY Filed June 2, 1970 Feb. 20, 1973 J. E. GORDON 3,717,071

ROPE FEED PISTON ASSEMBLY Filed June 2, 1970 2 Sheeps-Sheet 2 IN VE N T OF JOHN E. GORDON United States Patent 3,717,071 ROPE FEED PISTON ASSEMBLY John Edward Gordon, 337 Main St. E., Gait, Ontario, Canada Filed June 2, 1970, Ser. No. 42,789 Int. Cl. F01b 9/00 US. Cl. 92-137 4 Claims ABSTRACT OF THE DISCLOSURE A feed cable piston assembly and more particularly means for keeping the feed cable relatively free from dirt build-up and means for securing the feed cable to a driving piston head.

With some feed cable apparatus presently in use, a feed cable piston assembly is used to provide power for the feed cable apparatus. With such prior feed cable piston assemblies, the feed cable is generally terminated at the piston and fastened thereto. Experience has shown that such previous meas of fastening the end of the feed cable to the piston is unsatisfactory in that premature wear and breakage develops at the connection and because such connection is located within a relatively sealed piston chamber, such wear is diflic-ult to observe and the breakage is difiicult to repair without disassembly of the pisnot assembly.

By use of the present invention which includes a compression assembly for securing the feed cable to the pis ton, the cable is passed through the piston unbroken and accordingly occurrences of feed cable breakage and/or wear within the piston assembly is reduced.

Another feature of the present invention is passing the feed cable through sleeves made of urethane or the like. Such sleeves are secured at each end of the piston assembly and permit a controlled outward air leakage because of the uneven outer surface of the cable thereby preventing dirt from being carried by the feed cable to the interior of the piston assembly. The sleeves additionally provide a relatively frictionless wiping of the feed cable as it passes therethrough. I

These and other objects and advantages of this invention will become more readily apparent from a reading of the following description and drawings, in which:

FIG. 1 is a side cross-sectional view of a feed cable piston assembly constructed in accordance with the principles of this invention;

FIG. 2 is an expanded side view, partly in section, of the piston head shown in FIG. 1 and the means for securing such piston head to a feed cable passing therethrough; and

FIG. 3 is a side-elevational view of a drilling device embodying the principles of this invention and with a portion of the mobile side supports and frames being omitted.

An elongated feed cable piston assembly 50 comprises: an elongated hollow cylindrical piston casing 52; casing end caps 54 which sealingly receive respective ends of casing 52 within the inner ends thereof; and, as shown, a double acting piston head 56 which is slidingly and sealingly received within casing 52 thereby separating casing 52 into a retracting chamber portion 58 intermediate the rearward ends of head 56 and casing 52 and a feeding chamber portion 60 intermediate the forward ends of head 56 and casing 52.

A suitable elongated load transmitting flexible member such as feed cable 51 has a continuous unbroken portion thereof extending longitudinally through assembly 50 and fixedly secured to piston head 56in a manner as hereinafter described. For purposes of the hereinbefore and hereinafter description of piston assembly 50, forward and rearward shall refer respectively to the left and right as viewed in FIGS. 1 and 2.

End caps 54 have a generally cylindrical cross section and include an inner portion 62 and a smaller diameter outer portion 64. Inner portion 62 has a bore '65 therein to receive the respective end of casing 52 therein as specified above and is provided with a fluid conducting connection 63 communicating between the interior of each end cap 54 and a source of pressure fluid (not shown) such as compressed air. Outer portion 64 has a three-stepped bore 66 extending axially therethrough. Bore 66 includes bore portions 68, 70 and 72 which respectively progress inwardly from the outer ends of portion 64 and have respective decreasing diameters.

A cylindrical elastomeric sleeve 74 having an axial length and outer diameter thereof substantially equal to the respective axial length and diameter of bore portion 70 is received within bore portion '70. An end cap plug 76 which has a central bore 78 therethrough is releasably received within bore portion 68 to retain sleeve '74 within bore portion 70. Bore 78, bore portion 72 and the inner bore of sleeve 74 are in axial alignment and have diameters thereof substantially equal to the outermost diameter of the feed cable 51 thereby permitting cable 51 to pass therethrough during the reciprocal operation of piston assembly 50.

Pressure fluid leakage around the outside diameter of sleeve '74 is prevented by sleeve 74 seating against the inner end of plug 76 when the respective feeding or retracting chamber is pressurized from a suitable fluid pressure source (not shown). Leakage of pressure fluid does take place between the sleeve 74 and cable 51 due to the uneven outer surface of the cable 51 caused by the strands from which the cable 51 is manufactured. Such leakage prevents dirt and the like from being carried inside piston assembly 50.

Inasmuch as sleeve '74 is made of an elastomeric material, the above described leakage is substantially constant regardless of the pressure within the feeding or retracting chamber for when the pressure within

chamber

58 or 60 increases, such increase in pressure tends to compress the respective sleeve 74 and, as such, causes it to fit more snugly about cable 51 and thus reduce leakage at higher pressures. This compression of sleeve additionally compensates for excessive wear of sleeve 74 by maintaining a snug fit between sleeve 74 and cable 51.

Piston head 56 has a three-stepped bore 80 extending axially therethrough for receiving feed cable 51 therein. Bore 80 includes

bore portions

82, 84 and 86 which respectively progress forwardly from the rearward end of piston head 56 and have respective decreasing diameters. 'Feed cable 51 is fixedly engaged with piston head 56 by means of a compression sleeve assembly 81 which is insertable within

bore portions

82 and 84.

Compression assembly 8-1 includes a cylindrical elastomeric compression sleeve 88 which has an axial length thereof less than the axial length of bore portion 84 and which is received within portion 84 such that the forward end thereof is seated at the forward end of portion 84 and the rearward end thereof is intermediate the axial ends of portion 84. A suitable cylindrical spacer sleeve 90 is insertable axially within bore 80 such that the forward end thereof is engageable with the rearward end of sleeve '88 and the rearward end thereof is located intermediate the axial ends of bore portion 82. Bore portion 82 has the rearward end thereof threaded for threadably receiving a compression screw 92 partially therein. Compression screw 92 has a bore 94 extending axially therethrough. Bore 94, bore portion 86, the inner bore of sleeve 90 and the uncompressed inner bore of compression sleeve 88 are in axial alignment and have diameters thereof substantially equal to the outermost diameter of feed cable 51.

With such an arrangement of the compression sleeve assembly 81 as hereinabove described piston head 56 is fixedly secured to feed cable 51 by initially threading cable 51 through the piston head 56, the compression sleeve 88, the spacer sleeve 90 and the compression screw 92. After such initial threading, the piston head 56 is adjusted to the desired location on the length of cable 51. The compression screw 92 is then tightened thereby exerting an axial force on compression sleeve 88 through spacer sleeve 90 which communicates therebetween. The axial force compresses sleeve 88 thereby resulting in the elastomeric body thereof flowing into and around all the crevices formed by the wire strands of cable 51 and thus obtaining a firm but undamaging grip on cable 51. The compressed sleeve 88 additionally provides a fluid tight seal within bore 80.

It is to be noted that a feed cable assembly 50 as described hereinbefore is intended for use in any type of apparatus making use of a feed cable to feed and/or retract an element during the operation of such an apparatus. An example of the use of a feed cable assembly of this invention is shown and illustrated in my copending United States application Ser. No. 43,138, filed June 3, 1970 and assigned to the same assignee as is this invention.

The above copending application shows and more completely describes the employment of this invention in a drilling apparatus such as that depicted in FIG. 3 which includes a drill guide frame assembly 12 supported and rendered movable over a surface by a crawler sup port 14 of a type well known in the art. Frame assembly 12 is suitably movably supported by a .well known boom assembly 1 6. Frame assembly 12 supports a drill motor 20 thereon, which motor 20 is axially movable with respect to frame assembly 12 by means of the feed cable assembly 50 of this invention.

Although preferred embodiments of various features of this invention have been described and illustrated herein, one skilled in the art can readily embody the principles of this invention in other forms to obtain the same operation and advantages without departing from the scope of the invention, for example: although a double acting piston assembly is described hereinabove the invention herein can be adapted for use with a single acting piston assembly such as by feeding an element by means of the feed cable assembly of this invention and retracting by other mechanical means or gravity; the compression sleeve can be positioned in other loca tions than as described; different means of providing an axial force on the sleeve 88 are contemplated; a compression assembly can be provided at each end of the piston head if desired; sleeve 88 can be constructed of partially elastomeric materials and partially of other materials; other means for wedging the feed cable to the piston head are contemplated; and the like.

The description herein does not limit the structure of this invention and the invention is defined by the scope of the claims set forth hereinafter.

What is claimed is:

1. A feed piston assembly comprising: a substantially cylindrical elongated body element; an axial bore through said body element; an elongated load transmitting member having a continuous portion extending through said bore; a deformable member received within said 'bore and encompassing a portion of said load member; means attached to said body element for compressing said deformable member into frictional and sealing engagement with said portion of said load member and said body bore; a casing having an elongated intermediate portion with an axially extending bore therethrough within which said piston receiprocates; end portions of said casing having bores therethrough axially aligned with said bore through said intermediate portion; and said load transmitting member being a driving cable passing through said aligned bores.

2. A piston assembly as specified in claim 1 wherein said deformable member is formed at least partially of elastomeric material.

3. A piston assembly as specified in claim 1 additionally including elastomeric wiping sleeves fixedly disposed about said cable within said bores through said end portions, said wiping sleeves having an outer diameter thereof substantially equal to the diameter of respective bores through said end portions and having an axially extending bore therethrough of a diameter substantially equal to the outermost diameter of said driving cable to provide for a preselected amount of pressure fluid leakage outwardly between said cable and said casing ends.

4. A piston assembly as specified in claim 1 wherein said means attached to said body element includes a member having at least a portion thereof threadably received within said body bore.

References Cited UNITED STATES PATENTS 2,094,124 9/1937 Huffman 173-147 1,258,580 3/1918 Lassiter 24-126.3 982,727 1/1911 Jones 24-155 986,874 3/1911 Thomlinson 24-155 2,639,692 5/1953 Akers 92137 3,535,985 10/1970 Attebo J 92137 MARTIN P. SCHWADRON, Primary Examiner A. M. ZUPCIC, Assistant Examiner US. Cl. X.R. 173147