US2590196A - Retaining device - Google Patents

Description

March 25, 1952 H. MESSINGER 2,590,196

RETAINING DEVICE Filed April 25, 1947 3 r 5* J j.

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Lester ATTORNEY Patented Mar. 25, 1952 UNITED STATES PATENT OFFICE 2 Claims. (Cl. 13854) This invention relates to tubing or hose of flexible material used for the ventilation of mines, tunnels, the holds of ships and purposes of a generally analogous character, and more particularly to means for reinforcing and supporting such flexible tubing which inherently is not sufiiciently self supporting to alone retain its expanded form.

For many years it has been the practice to use flexible, fabric ventilating hose or tubing to ventilate remote spaces in mines, tunnels, ships holds and similar places by supplying fresh air under positive pressure to these isolated spaces. Such flexible tubing is usually impregnated or coated with rubber or like material and is generally made in sections varying in length so as to be conveniently connected together to form a continuous air passage to the desired'point.

Mine ventilating tubing of the character to which my invention is applicable is disclosed in a number of United States patents including No. 1,671,706, May 29, 1928, No. 1,779,258, October 21, 1930, and No. 1,863,624, June 21, 1932.

Toprovide internal support for such thinwalled, flexible, ventilating tubing atturns in its course it has been proposed in U. S. Patent No. 2,345,636 to provide short, collapsible, wire helices which are positioned inside the sections of tubing. When not in use as supporting members the wire helices are withdrawn from the tubing and collapsed by compressing the successive coils together and retaining the coils closely adjacent to each other by means of clamps which are adapted to hold the circumferential portions of the two terminal coils of the helix to- 'gether and retain all intermediate coils in axially compressed position between the terminal coils, to facilitate handling and storage until further need for them arises.

A principal object of this invention is to provide a greatly improved but inexpensive, reliable retaining device for holding the coils of the supporting wire helices in collapsed condition.

A further object is to provide such a retaining means positioned within the helix in such a manner as to be out of contact with the walls of the tubing supported by the helix;

' Another object is to 'provide' such -a retaining means integral with the wire coils themselves,

thereby reducing the weight, increasing the strength, and simplifying fabrication.

- Other objects will become apparent from the following description in which:

Figure l is a side longitudinal sectional view of a-length of flexible. ventilati-hgtubing supported by a wire helix constructed in accordance with my invention, the right hand end coil of the helix being shown in full for purposes of clarity while the remaining coils of Figure 1 are shown in section.

Figure 2 is a similar section of an axially compressed helix embodying my invention wherein the righthand end coil is shown in full while the remaining coils of Figure 2 are shown in section.

Figure 3 is a detail View of the retaining device of this invention in engaged position, the coils retained thereby being omitted for purposes of clarity.

Figure 4 is a side elevation of one type of clamp which can be used in connection with my invention.

Figure 5 is an end view of the clamp shown in Figure 4.

Figure 6 is a broken sectional plan view of a partial length of tubing, bent at an extreme angle topermit the negotiation of a sharp turn, supported by an extended helical member constructed in accordance with my invention, the maintenance of the bend being faciliated by the utilization of a clamp of the design of Figures 4 and 5.

Referring more specifically to the figures of the drawing, Figure 1 shows a single, wire helix embodying my invention in supporting position within a section of flexible ventilating tubing. These helices are fabricated from spring wire of appropriate thickness and normally assume the extended position shown unless forcibly retained by other means. The supporting helices are formed in slightly smaller diameter than the inside diameter of the tubing to be reinforced thereby so that they may be easily moved within the tubing as conditions of use may require. Preferably the supporting helices are fabricated in varying lengths which generally comprise fourteen to sixteen coils.

When not required as supporting members the helices are ordinarily withdrawn from the lengths of tubing, since, in the compressed form shown in Figure 2, they would offer considerable obstruction to the passage of air through the tube if they should rotate so that the compressed coils lay across the plane of air flow. To facilitate storage the withdrawnhelices are compressed to the 'form shown in Figure 2 and laid aside until they are again required.

In Figure 1, the terminal ends of the helical, wire supporting member are shown as formed into retaining elements which are designated I and 2, respectively. In the formation of these elements care is taken to insure that the wire length designated 3, shown only for the righthand element, follows the true helical course which all intervening coils take so that, when the helix is compressed to the form shown in Figure 2, all coils will contact their next adjacent coils around their entire circumferences, and the resulting bundle will assume a tight cylindrical form in which no single coil will lie outside or inside the limits of the cylinder thereby defined, but all will be neatly superimposed one on the other.

Retaining elements i and 2 are hooklike in form and are identical in shape, but element 2 is so disposed that the plane parallel to its hook portion lies at an angle of approximately ninety degrees to the plane parallel to the hook portion of element 1. The open portions of the hooks of I and 2 face outwardly, in opposite directions and away from the intervening coils.

The shank portions l of the hooks i and 2 are inclined at slightly opposite acute angles to the longitudinal axis of the helix when it is extended, but lie along the longitudinal axis of the cylinder formed when the helix is compressed. The disposition of the shank portions a relative to the longitudinal axes in the extended and compressed conditions is an important feature of the construction, since .ich facribation insures the balanced application of stresses over the complete circumferences of the coils and thereby insures that all coils will naturally superimpose one on the other in a condition of maximum stability when the helix is compressed to the position of Figure 2.

As shown in Figure 3, which depicts the reretaining elements and 2 in connected relationship, the hook portions are formed at the ends of the wire and constitute a continuation of the straight shank portions 4 which, in turn, are bent at angles of approximately ninety degrees to the straight lengths of wire 5 which continue on to form the helix. The shank portions 4 are of approximately equal length and about one half of the length of the compressed coil of Figure 2 so that, when elements i and 2 are engaged, the point of engagement will approxi-- mately coincide with the geometrical center of the cylinder formed by the axial compression. The straight lengths of wire 5 are each approximately equal to the radius of the helix.

The hook ends of both elements are bent back parallel to the shank portions 4 at an angle of approximately one hundred and eighty degrees, and the free ends extend a distance of less than the half the length of the shank portions. The inside curves of the hook portions are made somwhat greater than the diameter of the wire to facilitate easy engagement and disengagement without pinching of the wire in the hook curves. It will be understood that the wire of the. helix is of sufficient inherent strength and stiffness as to maintain the shapes and angles to which the end portions are bent, both under the strain of axial tension and under the other strains encountered in normal use. g

It is possible to remove the supporting helices from the tubing sections in the'extended conditions of Figure l, but it is usually more preferable to compress them to the compact form of Figure 2 prior to removal from the tubing. The supporting helices are easily compressed and their retaining elements engaged, one with the other, by manipulation through the walls of the tubing-when the air flow is momentarily. discontinued, since the tubing walls are easily flexed in any desired direction under these condtions. An attendant is thereby enabled to ascertain the location of the end members of each helix by touch against the tubing wall, and, when both ends are under control of the operator, the helix may be compressed by forcing the outside coils together and then engaging elements I and 2, whereupon the helix will be maintained in compact, shortened form until elements I and 2 are positively disengaged at the will of the attendant.

Figure 6 shows a length of tubing bent at a sharp angle of about ninety degrees and supported by a wire helix fabricated in accordance with my invention. To facilitate the maintenance of such a bend it is sometimes desirable to employ a clamp 9 to retain and support the central coils, which are subjected to the highest stresses due to the bending. On forming the bend there will also be some slackness in the tubing wall at the inside of the bend, and it is desirable to gather this slack material at a central point in such a manner that it will he outside the wire coils and not constitute a hindrance to the air passage within the tube. This dual function is accomplished by the clamp 9 which is shown in detail in Figures 4 and 5.

The clamp 9 comprises three freely separable elements, the two jaws or hook-like straps 5 and the square cross section, joining bar This construction permits ready disassembly of the three component parts by merely sliding the hook straps 6 from the central bar 1, whereupon the straps can be hung from hooks on a workmans belt while a number of the bars may be gathered into a compact bundle, making it easy to trans port the clamps through the narrow confines within which ventilating tubing is usually installed. When a clamp 9 is needed for the purposes described the two hook straps 6 are slid over the square bar 1 in opposed relationship, and the central coils and slack tubing are gathered in the space between the straps, after which the two straps are pushed firmly together. Because of the elasticity of the coils, a counter force is exerted at an acute angle to the straps which tends to rotate them about an axis perpendicular to bar I. Bar 1 resists such force moments, and the straps 6 thereupon bind on bar I, forming a stable clamp which may be easily disassembled by an attendant whenever desired.

Clamps 9 are not intended for holding the ventilating tubing to any surrounding supporting surfaces but only to retain the central coils and the fabric slackness occurring at tubing bends. It is customary to support the ventilating tubing by hanging it from wires strung along walls and ceilings, the wires being threaded through, or otherwise engaged with, fabric or metal tab pieces 8 carrying central eyelets, which tab pieces are sewn, riveted or otherwise joined to the tubing walls at appropriate intervals and which are in no manner associated with the supporting helices.

The retaining devices made in accordance with my invention are simple and economical to manufacture, are of high strength, and possess the additional advantage of not chafing or puncturing the tubing walls because they do not bear against them.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to 5 the specific embodiments thereof, except as defined in the appended claims.

I claim: 1. An internal support for flexible gas-conducting tubing consisting of an extended wire helix, and means within the periphery of the a helix for holding said helix in collapsed or compressed condition, comprising mutually engageable means integral with the ends forming hooks made from the ends of said wire helix and reposing wholly within the helix.

2. The invention of claim 1 in which the hook members are made of the same tension material as the wire helix.

LESTER H. MESSINGER.

6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 439,210 Thome Oct. 28, 1890 1,711,300 Ziegler Apr. 30, 1929 2,345,636 Stickler Apr. 4, 1944 FOREIGN PATENTS Number Country Date 10,567 Great Britain of 1915

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