US225516A - Flexible shaft and sheath - Google Patents

Description

- W; H. GATES.

flexible Shaft and Sheath.

A No. 225,516. Patent "l 16,

IN VENTOR Gama MANOR EY.

NPETERS, PNOTO-LITHOGRAFHER, WAsNlNromb c,

UNITED STATES PATENT OFFICE.

WILLIAM H. GATES, OF PHILADELPHIA, PENNSYLVANIA.

FLE XIBLE SHAFT AND SHEATH.

SPECIFICATION forming part of Letters Patent No. 225,516, dated March 16, 1880. Application filed December 1, 1879.

To all whom it may concern: Beit known that I, WILLIAM H. GATES, of Philadelphia, in the State of Pennsylvania,

have invented certain new and useful Improvements in Flexible Gables or Shafts and Shaft-Sheaths for Dental Engines and other Machinery, of which the following is a specification.

My invention is directed to flexible cables or shafts and to shaft-sheaths intended particularly. for dental engines, but also adapted to be used in other engines or machinery.

It is my object to obtain a shaft that, with the requisite flexibility, shall be more firm, prompt, and positive in action than the ordinary shaft heretofore used, and shall not be injuriously affected by the torsional strain to which it may be subjected.

It is also my object, as regards the sheath or sleeve for enveloping the flexible shaft, to obtain aflexible sheath which shall be lighter and contain less .metal than the ordinary sheath heretofore employed for that purpose, and also shall have more resiliency as well as flexibility. The weight of the ordinary sheath is such as to interfere materially with delicacy of manipulation in the use of dental engines, and to tire and fatigue the operator. My improvement obviates this and other defects in the ordinary sheath.

My invention also relates to means for compensating the difference in flexure between the cable and the flexible non-rotating sheath which ordinarily covers it. p

The nature of my invention and the manner in which the same is or may be carried into effect will be understood by reference to the accompanying drawings, in which have represented my several improvements in their preferred form.

Figure 1 is a perspective view of the fiexi ble shaft and head of a dental engine, the hood that covers the driving'pulley being removed and a portion of the sheath being broken away to show the shaft within. Fig.2 is a longitudinal vertical central section of the pulley, head, and part of the shaft and sheath. Fig. 3 is a View, 011 an enlarged scale, of a portion of the shaft and the sheath. Fig. 4 is a transverse section of the shaft. Fig. 5 is a longitudinal vertical central section of a shaft in which also coiled spirally around it.

the body-coil is provided with a modified form of filling consisting of sectional filling-pieces. Fig. 6 is a view of one of the filling-pieces.

The flexible shaft is made up of three parts a bodycoil, A, a wrapper, B, and a flexible filling-core, C. The body-coil A consists of metal ribbon, which is by suitable machinery coiled spirally. It is then supported from within by a continuous coil of line wire, 0, and is covered by an external metallic Wire, B, The wrapper can be applied in various ways, its spirals running in the same direction with or preferably in an opposite direction from the spirals of the body-coil.

The body-coil may be made of a single flat steel strip or ribbon, or of two or more such strips laid flat side by side in the same plane and coiled. In the drawings I have shown it as composed of two strips.

The body-coil, the flexible filling-core G, and the wrapper are formed while the metal of which they are composed is tem ')ered. The two former are then applied to each other and tempered; but the latter, when practicable, may be left untempered for the sake of retain ing its original polish. As each turn of the body-coil is supported by about eight (more orl'ess) turns of the wrapper, my present experience has made the additional strength acquired by tempering the latter seem unnecessary; but as the inner surface of thebody-coil is protected from oxidation in tempering by the filling-core, so the outer should be closely wrapped with flne iron wire during that process.

As the softest wire retains a degree of temper and recoil somewhat after being coiled, I have found it convenient to solder the free end of the core-wire to its mandrel when wound, and then insert it within the body-coil before releasing. I also form the wrapper separately and of such dimensions that it can only be slipped over the body-coil while the latter is put under torsion. This application I accomplish readily by temporarily soldering one end of a mandrelinto one end of the body-coil. The wrapper being slipped on this mandrel and torsion applied to the extremes of mandrel and body-coil, the latter will be slightly contracted,and the wrapper can then be readily moved to its place on the body-coil. Upon releasing torsion this external support of the body-coil is perfect.

The flexible filling-core G, formed, as shown in Figs. 2 and 3, of fine closely-coiled wire inserted in and exactly fitting the bore of the body-coil A, and extending throughout its length, acts, in connection with the borders or edges of the turns or folds of the body-coil which bear solidly against one another, to firmly support the body-coil and to prevent it from contracting in diameter.

Various forms of filling-core may be employed. That which has just been described is the one which I prefer. I can, however, use the means shown in Figs. 5 and 6, consistin g of short cylinders or sectional fillin g-pieces with rounded extremities which are inserted in and fit the bore of the body-coil, as represented.

The body of the shaft is thus composed of a tube formed of a coiled flat steel ribbon or strip, which serves admirably as a powertransmitter, and yet has all needed flexibility, and this steel tube is supported internally by a flexible filling-core and externally by a tubular metallic close-fitting and flexible Wrapper made of wire, preferably very fine. v

The flexible non-rotating sheath or casing D, instead of having a body of spirally-coiled brass wire, as is usually the case, is provided with a flexible body composed of a thin fiat spirally-wound steel ribbon, 8, covered with any suitable external material, such as the usual chamois, 00, which, in turn, is enveloped by an external braided cover, 3 as shown.

This sheath is preferable, on many accounts, to the ordinary sheath. I reduce the weight to a very great extent, the metal which I use having less than half the weight of the brass wire in an ordinary sheath of the same length. I not ofily reduce the weight, which is the most material item, but I also lessen the cost of production and obtain a better sheath in every respect.

To compensate the difference in flexure between the sheath and the flexible cable or shaft which it surrounds, I make that end of it next to the head E to consist of a two-part sleeve, the two parts F G of which are movable longitudinally with respect to one another.

The part G is a sleeve, which screws upon a tubular externally screw-threaded projection, H, on the head or frame E, or is otherwise attached to said frame. The part F is a metal tube, which can slide lengthwise in the sleeve G, and is provided at its end with a collar or flange, a, by which it is retained within the sleeve, the collar meeting a shoulder at the front end of the sleeve. Between the end of the tube F and the frame or projection H on the frame is interposed a spiral spring, I. In the frame E is mounted the driving-pulley J, fixed on a hub or short tubular shaft, K, mounted in bearings in frame E. The

rear end of the flexible shaft is soldered or otherwise fastened to a cylindrical rod, L, which cal to correspond with the pulleyjournals.

One only of the bearings in this instance is movable. It is formed in or carried by an arm, M, which at its lower end is fixed to and seated in the frame E, and is held in place by two binding-screws, On the opposite side of the frame is a set-screw, g, which projects from the frame against the face of the arm M at a point intermediate between the bindingscrews f. By adjusting this set-screw so that it shall'project more or less the distance between the arm and the contiguous face of the frame can be varied, and consequently the distance between the two bearings can be increased or diminished at pleasure. This is one convenient way of accomplishing the resu'lt. It is manifest, however, that the adjustment of the bearings can be secured in various other ways and by the use of devices which will readily suggest themselves.

The removable covering-hood N fits down over the pulley, as shown in Fig. 2. It moves in or on suitable guides g h in the pulleyframe, and is provided with end slots to permit it to pass down over the upper part of the frame.

Having now described my improvements, what I claim, and. desire to secure by Letters Patent, is-

1. In a flexible shaft or cable, a body-coil composed of a spirally-wound steel ribbon or fiat strip, in combinationv with a flexible filling-core, substantially as set forth.

2. In a flexible shaft or cable, a body-coil composed of a spirally-wound metallic ribbon or flat strip, in combination with an external wrapper of closely-wound spirally-coiled fine wire, substantially as set forth.

3. A flexible cable or shaft composed of a tubular body-coil, a wrapper, and a flexible filling-core, substantially as set forth.

4. The flexible sheath composed of a bodycoil of thin flat spirally-coiled metallic ribbon, combined with a suitable cover or jacket, substantially as hereiubefore set forth.

5. In combination with the flexible non-rotating sheath and the frame, the two-part sleeve and the interposed spring, substantially as set forth.

In testimony whereof I have hereunto signed my name this 24th day of November, A. D. 1879.

W. H. GATES.

Witnesses FRANK R. STEVENSON,

SAM. O. WOOLMAN.

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