US2816524A

US2816524A - Apparatus for marking wires and cables and the like

Info

Publication number: US2816524A
Application number: US554319A
Authority: US
Inventors: Ridings Geoffrey Norton
Original assignee: BICC PLC
Current assignee: Balfour Beatty PLC
Priority date: 1955-12-20
Filing date: 1955-12-20
Publication date: 1957-12-17
Anticipated expiration: 1974-12-17

Description

Dec. 17, 1957 G. N. RlDlNGS APPARATUS FOR MARKING WIRES AND CABLES AND THE LIKE Filed Dec. 20, 1955 w u //9 M 2 0M 7 K w Him A, U

United States Patent APPARATUS FOR MARKING WIRES AND CABLES AND THE LIKE Geoflrey Norton Ridings, Eccles, Manchester, England, assignor to British Insulated Callenders Cables Limited, London, England, a British company Application December 20, 1955, Serial No. 554,319

3 Claims. (Cl. 118-316) This invention relates to apparatus for applying to the surface of a longitudinally travelling wire, cord or cable (all hereinafter included in the term'cable) one or more helical stripes of a marking fluid. In particular it concerns apparatus of the kind comprising a rotatably driven marking head by which striping of the cable is effected by causing marking fluid to flow from one or more reservoirs through one or more channels to an applicator having one or more outlets for fluid that are directed towards the surface of the cable travelling axially through the head, so that a small stream of the fluid issues from each outlet and impinges on the surface of the cable and forms a helical stripe thereon as the head rotates and the cable travels axially through it.

In a marking head of the kind above described it has been proposed to use an applicator in the form of a bushing having a flared or bell-mouthed entrance leading to a centrally throated aperture for the passage of the cable and having radially directed marking fluid passages in its wall which open into the central throat of the bushing. With this form of applicator 'difliculties may sometimes arise in the event of the cable varying in diameter. If the cable diameter is less than that for which the applicator is designed, the conductor may vibrate laterally and uneven marking may result. If it is greater than that for which the applicator is designed, or if it is locally misshaped, there will be excessive tension in the cable and the cable may become permanently stretched or even be broken.

The present invention provides an improved form of applicator of the centrally throated bushing type which avoids or at least reduces to a considerable extent the difiiculties due to local variations in size of the cable to be striped.

Our improved applicator comprises a centrally throated bushing formed of two or more separable segmental parts which are held together by a sleeve of soft cellular rubber which is supported externally by a sleeve of relatively rigid material. One or more ports are provided in the walls of the cellular rubber sleeve and the supporting sleeve each of which ports registers with a radial passage in the wall of the split bushing which leads to the interior of the throated portion of the bore. Preferably the diameter of the throated portion of the bore is locally increased in the region of the radial passage or passages.

The term rubber when used herein includes natural and synthetic rubber compositions and compositions containing other polymeric compounds as principal ingredients, which are rubbery and elastic at room temperatures, and the term cellular rubber includes multi-cellular rubber, that is, rubber having an open cell structure such as sponge rubber and latex foam rubber, and uni-cellular rubber, that is, rubber having a closed cell structure and usually referred to as expanded rubber. It is also to be understood that the term centrally throated bushing does not imply that the bushing has a throat located mathematically intermediate its ends but merely that the bore of the bushing comprises a throated portion, that is,

ice

a portion of reduced diameter, located between two portions of greater diameter, one of which constitutes a flared.

or bell-mouthed entrance portion and the other of which may or may not be of corresponding form.

With this improved construction the two or more segmental parts are normally held together but on the passage of a locally misshaped or oversized part of the cable along the flared or bell-mouthed entrance to the central throat portion pressure is exerted on these segmental parts. This pressure is transferred to the cellular rubber sleeve or liner which yields elastically under the pressure and allows the parts of the bushing to separate temporarily to allow the locally misshaped or oversized part of the cable to pass through the throat. After the passage of the enlarge: ment the two or more parts of the bushing are reclosed by the inward pressure exerted by the elasticity of the soft cellular rubber liner,

The wall thickness of the rubber liner is not very critical in that a variety of thicknesses can be used satisfactorily under certain conditions. When the liner is made of soft sponge rubber, a wall thickness of one-eighth of an inch has so far been found to give the best results over the widest range of cables striped.

The internal dimensions of the external sleeve, the external dimensions of the split bushing and the thickness of the rubber liner are preferably so chosen that the rubber liner when assembled with its supporting sleeve and the split bushing is under as little compressive stress as possible, that is to say they are so chosen that the initial stress merely suflices to hold the two or more segmental parts of the split bushing together and to prevent marking fluid from the ports penetrating between contiguous surfaces of the supporting sleeve and the liner and between the contiguous surfaces of the liner and the split bushing.

A preferred form of applicator in accordance with the invention will now be described by way of example with reference to the accompanying drawing wherein:

Figure 1 is a sectional elevation of the applicator, and

Figure 2 is a plan of the applicator shown in Figure l.

On referring to Figure 1 it will be seen that the centrally throated bushing 1 is made up of two

complementary parts

2 and 3 which form a split bushing, the split being in the diametral plane 4. Its bore comprises a bell-mouthed entrance 5 leading to a short portion 6 of uniform diameter, for instance a diameter equal to the anticipated maximum cable diameter plus .003 inch. This is followed by a portion 7 of about the same length but having a diameter equal to the diameter of the portion 6 plus .004 inch. Beyond these two portions which form the throat of the bushing there is a portion 8 of greater diameter. The entire length of the bore has a highly polished finish.

To allow contact to be maintained between the travelling cable and the wall of the portion 6 when the diameter of the former is below the nominal diameter, the crosssecti'on of each half of the bushing is reduced to a segment that is less than a semi-circle as by removing from its diametral surface 4 a layer having a thickness equal to where D is the maximum anticipated diameter of the cable to be striped plus approximately .003 inch and d is the anticipated minimum diameter of the cable.

In the wall of each half of the bushing is a radially extending passage 9 for the supply of marking fluid to the throated portion of the bore. This passage has a diameter approximately corresponding to the width of the stripe required and preferably has its axis normal to the diametral plane in which the bushing is split, As its flared inlet end the split bushing has an external collar having a diameter greater than the external diameter of a cellular rubber sleeve 11, which fits over the remaining part of the split bushing and lightly presses the two halves together. To this end the inner diameter of the sleeve 11 is just slightly greater, say .001 inch greater, than the outer diameter of the bushing'along its minor axis. The sharp edges of the diametral surface of each half of the bushing are removed to prevent damage to the cable and the cellular rubber sleeve and to ensure that the corresponding halves of the bushing'may come together properly. There are two ports or passages 12 in the rubber sleeve which register with the passages 9 in the split bushing. The passages 12 are of considerably larger diameter than those in the Wall of the split bushing.

The bushing and its rubber sleeve are housed in a etal sleeve 13 having a circular flange 21, the projecting part of the external collar 10 of the split bushing entering a recess 14 in one end of the metal sleeve 13 and positively locating the split bushing against any tendency to be carried forward by the travelling cable. A clearance is left between the circumferential surface 15 of the collar and the adjoining surface 16 of the recess in the metal sleeve to allow the split bushing to float laterally relative to the metal sleeve.

Ports 17 are provided in the wall of the metal sleeve 13 to register with the passages 12 and 9. A locating key 18 held in a recess in the flange 21 projects radially inwards across the face of the recess 14 and is an easy fit in a keyway cut out of the external collar 10 of the split bushing 1. This serves to locate the split bushing in the metal sleeve with the ports 17 and the passages 9 in alignment. The ports 17 extend through radial projections to form nipples 20 for the attachment of tubes leading from appropriately placed reservoirs containing marking fluid. The applicator may be detachably secured to the marking head by the circular flange 21 so that the axis of the bushing is in alignment with the axis of rotation of the head, which is preferably vertical.

We have found that the use of our improved applicator makes it possible to apply stripes of uniform width and appearance to cable which, owing to imperfections in manufacture, may vary in diameter by as much as .020 inch. This is due to the fact that the throat of the split bushing at all times hugs the cable and so keeps the point of delivery of the marking fluid a constant distance from the surface of the cable. It will be appreciated that owing to its simplicity of construction our improved applicator may be readily dismantled, cleaned and re-assembled.

What I claim as my invention is:

1. An applicator for applying at least one stripe of marking fluid to a cable passing through the applicator, comprising a centrally throated bushing consisting of at least two separable segmental parts, a sleeve of soft cellular rubber surrounding and holding said segmental parts together, a sleeve of relatively rigid material surrounding and providing external support for said sleeve of soft cellular rubber, at least one port in the wall of said cellular rubber sleeve, a port in the wall of said supporting sleeve in register with the first said port and in register with said ports a radial passage in the wall of said bushing which leads to the interior of the throated portion of said bushing.

2. An applicator for applying at least one stripe of marking fluid to a cable passing through the applicator, comprising a centrally throated bushing consisting of two separable segmental parts, a sleeve of soft cellular rubber surrounding and holding said segmental parts together, a sleeve of relatively rigid material surrounding and providing external support for said sleeve of soft cellular rubber, a radial passage in the wall of at least one of said segmental parts leading to the interior of the throated portion of said bushing, a port in the wall of said cellular rubber sleeve which registers with said radial passage and a port in the wall of said supporting sleeve which register with the first said port, the diameter of the throated portion of said bushing being locally increased in the region of said radial passage.

3. An applicator for applying at least one stripe of marking fluid to a cable passing through the applicator, comprising a centrally throated bushing divided about a diametral plane, the cross-section of each half of said bushing being a segment that is less than a semi-circle, a sleeve of soft cellular rubber surrounding and holding together said two segmental parts, a sleeve of relatively rigid material surrounding and externally supporting said sleeve of soft cellular rubber, a port being provided in the Wall of said cellular rubber sleeve and a port being provided in the wall of said supporting sleeve which ports register with a radial passage in the wall of said bushing for the conveyance of marking fluid to the interior of the throated portion of the bushing.

References Cited in the file of this patent UNITED STATES PATENTS 293,095 Sawyer Feb. 5, 1884 1,501,764 Flint July 15, 1924 2,370,314 Jenner Feb. 27, 1945 2,407,337 Kolter Sept. 10, 1946 2,474,088 Brown June 21, 1949 2,576,961 McCarthy Dec. 4, 1951 2,578,260 McPherson et a1 Dec. 11, 1951 2,610,607 Isenberg Sept. 16, 1952