US2694568A - Friction device and anchorage therefor - Google Patents

Description

Nov, 16, 1954 J. w. wATsoN 2,694,568

FRICTION DEVICE AND ANCHORAGE THEREFOR Filed March 4, 1949 @Q -z 76.2 @6.5 F264. H65.

United States Patent Office 2,694,568 Patented Nov. 16, 1954 FRICTION DEVICE AND ANCHORAGE THEREFOR .lohn Warren Watson, Wayne, Pa., assignor to John W ar ren Watson Company, Philadelphia, Pa., a corporation of Pennsylvania Application March 4, 1949, Serial No. 79,667

6 Claims. (Cl. 267-49) This invention relates to a self-sealing, friction-controlling bearing device for spacing two relatively reciprocating bodies and, in particular, to a device for spacing two adjacent leaves of a multiple leaf spring or other bodies which may be called upon to operate in an atmosphere of grit and/ or abrasive laden waters.

A particular object of my invention is to provlde. a unit spacing device which has for its base a textile matrix of homogeneous unit construction.

A further particular object of my invention is to provide a matrix of textile construction which will readily accommodate a thorough impregnation thereof and at the same time present a necessary surface contour tlatness and smoothness to impart to a coating thereof. a surface of suitable atness to largely engage the surface against which it is to opeerate.

A further object of my invention is to employ, in connection with an impregnated woven base matrix as above, a coating of friction material of sufficient yieldability to closely and readily conform, under the pressures and movements imposed in service, to the minor irregularities of the opposing surface and thus form a tight seal against the entry of grit and/or abrasive laden waters therebetween.

A further object of my invention is to provide a weave structure which can accomplish the above required flatness and smoothness of surface contour even when employing the relatively course thread sizes and low counts found in webbings generally.

A further object of my invention is to provide a unit spacing device of sufficient strength to satisfactorily withstand, without fray or distortion, the pressures and movements imposed in service.

A further object of my invention is to provide means for limiting the relative movements between a friction spacing device and one of the two relatively reciprocating bodies in any direction--lengthwise, sidewise, or oblique, and for positively anchoring said device against displacement from between said bodies while in service.

Prior practice in the matter of employing a textile material to act as a unit base matrix in the formation of a friction spacing device has overlooked the important factor of self-sealing and a necessary surface contour atness therefor. Impregnated textile spacing devices as heretofore used for interleaf spring duty have employed cotton webbings of plain weave construction using fairly course thread sizes and low counts and presenting surface contours of decided holes, hummocks and valleys which flatten out, if at all, only after long service and during all of which time grit and abrasive laden waters have had free access to the valleys, allowing grit deposits to accumulate and become embedded in the spacer surface. This embedded grit has not only destroyed the quality of the intended friction control, but has also been found to act as a lapping agent and to seriously abrade the leaf surfaces.

`One naturally thinks of woven cotton as a relatively softmaterial which would readily fiatten out under the weight of a car and its passengers. In years past I myself have been guilty of such thought.

l have now discovered that cotton webbing, even of relatively open and soft construction, becomes quite hard and unyielding when impregnated with material of a toughness which is required for these gruelling, reciprocating duties. Therefore, it becomes apparent that a textile, to serve satisfactorily as a unit base matrix for such spacing and self-sealing duty, must present,

initially, a surface contour, not of hills and valleys, but of decided flatness and smoothness. The coating alone of a matrix cannot be relied upon to give a necessary flatness of surface because the contour of a coating follows more or less the contour of the surface which supports it.

In my search for a type of weave which would satisfactorily meet the requirements listed above as my objectives, and wishing to avoid, if possible, having to resort to the ne thread sizes and/or high counts such as would be required for example in a plain weave to get the necessary surface flatness, I have found that weaves of the twill family, for example, are eminently suited and that webbings of such weaves may be had in a variety of single ply constructions and in a great variety of constructions involving two or more plies.

For comparable surface contour llatness and smoothness, a twill weave is able to employ coarser threads and lower counts than can a plain weave because of the consecutive side by side laying of the warp threads in the twills, as shown, by way of example, in Figs. l through 5.

Figures l through 5 illustrate different weave moditcations found suitable in the construction of the friction spacing member.

Fig. 6 is a fragmentary side elevation, partly in section, of a leaf spring showing the friction spacing member anchored in position.

Fig. 7 is a View similar to Fig. 6 showing a modification of the anchoring means for the spacing member.

In Figs. 1, Zand 5, I show diagrams of some of the more common twill weave faces which are well suited for the duties herein. i Fig. l shows a warp effect twill having three risers and one sinker in each repeat (three up and one down). Fig. 2 shows another example of warp effect twill having two risers and one sinker in each repeat (two up and one down). This latter weave, a well known variety of the twill family, is generally referred to as a drill. Fig. 5 shows an evensided twill wherein the risers and sinkers are equal, there being two risers and two sinkers in each repeat (two up and two down).

In Figs. 3 and 4 are shown two examples of a not' common variety of warp effect twill weave which 1 designate as two-step twill. Fig. 3 shows a warp effect having three risers and two sinkers in each repeat (three up and two down). Fig. 4 shows a warp effect having four risers and two sinkers in each repeat (four up and two down). The diagonal line in the more orthodox twill weave constructions is caused b y moving the interlacings one pick higher on successive warp threads. In the variety of twill shown in Figs. 3 and 4, a somewhat steeper diagonal line is effected and is caused by moving the interlacings two picks higher on successive warp threads. Pick is another-term for a filling thread. In the above twostep twills it might be found expedient to employ a plain weave in forming the selvage edges.

To clarify the weave diagrams, Figs. l through 5, 1t should be noted that: Since an interlacing indicates that various threads go over and under each other, it is convenient to indicate a particular warp thread over a given -iilling thread by using a marked block. This marked block is called a riser. If the block is not marked it is called a sinker and indicates a particular warp thread under the corresponding filling thread.

For duty as a matrix for a friction spacing device, where the movements against the spacer will be in line with the longitudinal direction of the webbing, which is also of course in line with the warp threads, a warp effect twill is preferable to a filling effect twill.

Warp effect twills have more risers than sinkers in a repeat, therefore more warp than filling on the face of the fabric.

There are two methods of anchoring a spacing device between two relatively reciprocating members. The method commonly in use is to anchor the device firmly with respect to one of the members and thus cause it to be driven back and forth with relation to the other member. This concentration of the work against one surface only of the spacing member means that a self-sealing smoothness is imperative only on this one surface. I shall hereafter refer to the abovemethod as: Fixed anchorage.

The other method of anchorage (provided for in my pending application Serial No. 743,997, now Patent 2,621,922, issued December 16, 1952) permits movements to take place equally between the spacer and both of the relatively reciprocating members. This therefore requires that adequately flat self-sealing surfaces must be provided on both faces of the spacer. I shall hereafter refer to this method as: Floating anchorage.

Where cost is a factor, and where duty permits the use of a matrix of single ply construction, I prefer, for fixed anchorage, a matrix of even-sided twill or two-step twill. In a single ply matrix, for floating anchorage, I prefer even-sided twill.

For the above single ply duty, in connection with fixed anchorage, I prefer a two-step twill rather than the warp effect twill shown for example in Fig. l, because of the closer interlacings and hence stronger structure provided by the two-step construction. In the warp effect twill, Fig. 1, each filling thread passes under three consecutive warp threads before tying in with a warp thread. In each of the two-step twill constructions here shown, Figs. 3 and 4, no filling thread passes under more than two consecutive warp threads before tying in with a warp thread. This closer interlocking of the threads and resultant strength is of particular value for fixed anchorage duty.

For those duties requiring a matrix thickness indicating a preference for a construction of two or more plies, I prefer a construction which provides some form of warp effect twill on both faces. This preference would follow for either fixed anchorage or oating anchorage duty.

Referring to Fig. 6, dealing with anchorage means for holding a friction spacing member against displacement from between two relatively reciprocating bodies, I here show two adjacent leaves of a multiple leaf spring to represent such bodies. Numerals 1 and 2 indicate the spring leaves. Numeral 3 indicates an elongated anchorage hole in one of the leaves adjacent an end thereof. Numeral 4 indicates a friction member spacing the leaves 1 and 2.v Numerals 4a indicate surface coatings of friction material supported by friction member 4. Numerals 5 indicate two stud-like anchor members having their ends spun over and into mesh with a friction mgnber.V

As a means for anchoring a relatively fragile member such as one employing a textile matrix as its base, there is some advantage in employing two relatively spaced anchor members rather than a single member in that each of the two members may be pushed in one direction only instead of alternately back and forth as would be the case with a single member. This insures somewhat greater stability. For example, when attempting to loosen a tent peg one does not push it against the earth in one direction only as it has been found that by pushing it back and forth in two opposite directions the loosening job is more quickly and easily accomplished. Furthermore, the individual round stud members here shown may be readily hopper fed and simultaneously installed in the friction member with existing standard machines.

Referring to Fig. 7, numerals 1a and 2a indicate two adjacent leaves of a multiple leaf spring. Numerals 3a indicate two relatively spaced and slightly elongated holes in leaf 2a. Numerals 3b point to dotted lines which indicate two relatively spaced holes which closely fit stud members 5. Numeral 4 indicates a friction member spacing the leaves 1a and 2a. Numerals 4a indicate surface coatings of friction material supported by friction member 4. The slightly elongated holes 3a would be used in preference to holes 3b if it is desired that each stud member be pushed in one direction only as is the case with hole 3 Fig. 6. Either of thealternate arrangements providing two spaced holes instead of one elongated hole might be found expedient from a manufacturing standpoint or to provide additional bearing area between the leaves and the friction member.

While` I have here illustrated and described my invention more specifically as applied to use in connection with a leaf spring, it should be understood that I do not limit myselfV to this specific use of the invention as it is quite apparent that it is equally well. adaptedl for use as a friction spacing means in numerous other mechanisms wherein two bodies are relatively subjected to pressures and reciprocating movements.

I claim:

l. 1n a device for frictionally opposing reciprocating movements between two adjacent leaves of a leaf spring or other two relatively reciprocating bodies under pressure, a textile matrix uniformly impregnated through its entire thickness with a water-proofing, toughening and friction-controlling compound whereof the static and dynamic co-eflicients of friction are sufficiently in balance to avoid setting up destructive spasmodic actions and/or objectionable noise-producing vibrations, said matrix being of a twill weave construction whereof the warp threads extending on the face of the matrix and in line with the reciprocating movements compose more than fifty percent of the total face area.

2. In a device for frictionally opposing reciprocating movements between two adjacent leaves of a leaf spring or other two relatively reciprocating bodies under pressure, a textile matrix uniformly impregnated through its entire thickness with a waterproofing, toughening and friction-controlling compound whereof the static and dynamic coefficients of friction are sufficiently in balance to avoid setting up destructive spasmodic actions and/or objectionable noise-producing vibrations, said matrix being of warp effect twill construction with the warp threads extending in the direction of said reciprocating movements.

3. In a device for frictionally opposing reciprocating movements between two adjacent leaves of a leaf spring or other two relatively reciprocating bodies under pressure, a textile matrix uniformly impregnated through its entire thickness with a waterproofing, toughening and friction-controlling compound whereof the static and dynamic coefficients of friction are sufficiently in balance to avoid setting up destructive spasmodic actions and/or objectionable noise-producing vibrations, said matrix being of multiply warp effect twill construction with the warp threads extending in the direction of said reciproeating movements.

4. In a device for frictionally opposing reciprocating movements between two adjacent leaves of a leaf spring or other two relatively reciprocating bodies under pressure, a textile matrix uniformly impregnated through its entire thickness with a waterproofing, toughening and friction-controlling compound whereof the static and dynamic coefficients of friction are sufficiently in balance to avoid setting up destructive spasmodic actions and/or objectionable noise-producing vibrations, said matrix being of two-step warp effect twill construction as disclosed and with the warp threads extending in the direction of said reciprocating movements.

5. In a device for frictionally opposing reciprocating movements between two adjacent leaves of a leaf spring or other two relatively reciprocating bodies under pressure, a textile matrix uniformly impregnated through its entire thickness with a waterproofing, toughening and friction-controlling compound whereof the static and dynamic coefficients of friction are sufficiently in balance to avoid setting up destructive spasmodic actions and/or objectionable noise-producing vibrations, said matrix being of multi-ply warp effect twill construction with the warp threads extending in the direction of said reciprocating movements and carrying on at least one surface thereof a sealing coat presenting frictional properties as above and being sufficiently yieldable under the pressures and movements imposed in service to conform to irregularities of the leaf surface against which it operates.

6. As a means for spacing and smoothly damping the reciprocating movements between two adjacent leaves of a leaf spring or other two relatively reciprocating bodies under pressure, a spacing device comprising a textile matrix impregnated with a water-proofing, toughening and friction-controlling compound whereof the static and dynamic coefficients of friction are effectively equalized, said textile matrix being of twill weave construction wherein the warp thread content provides a greater bulk or portion of the whole than does the filling thread con tent and wherein the warp threads extend in the direction of the reciprocating movements.

(References on following page) References Cited in the le of this patent Number UNITED STATES PATENTS Number Name Date 2,476,367

409,767 Barraclough Aug. 27, 1889 5 2,012,029 Weiser Aug. 20, 1935 2,126,042 Reinz Aug. 9, 1938 2,280,201 Thompson Apr. 21, 1942I 6 Name Date Watson etal. May 11, 1943 Hildenbrand Aug. 15, 1944 Guernsey `Iuly 19, 1949 OTHER REFERENCES Nisbet: Grammar of Textile Design, 3d ed., 1927; page 25, Fig. 31; and page 30, Fig. 52.

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