US3137021A

US3137021A - Brush strip construction

Info

Publication number: US3137021A
Application number: US187388A
Authority: US
Inventors: Richard B English
Original assignee: Industrial Brush Co
Current assignee: Industrial Brush Co
Priority date: 1962-04-13
Filing date: 1962-04-13
Publication date: 1964-06-16
Anticipated expiration: 1981-06-16

Description

June 16, 1964 R. B. ENGLISH BRUSH STRIP CONSTRUCTION Filed April 15, 1962 rap/V575.

ma mu i B A H M United States Patent BRUSH STRIP CDNSTRUCTION Richard ll. English, Pasadena, Calif, assignor to Industrial Brush (Iornpany, Arcadia, Calif, a corporation of California 7 Filed Apr. 13, 1962, Ser. No. 187,388

7 @laims. (Cl. 15-182,)

T his invention relates to a brush strip construction and more particularly to a helical or curved brush strip means especially adapted to immovably retain brush filament material and to restrain a brush filament retainer element against longitudinal displacement or movement with re spect to a brush strip member during a sweeping operation.

In certain constructions of cylindrical brush means used for various industrial purposes, such as street sweeping, and in which the cylindrical brush means is rotated rapid ly about an axis of rotation, channel-like brush strip members carrying brush bristles or filaments, may be disposed in circular or in helical relation about said axis and are usually held by a single wire core element Within the member. In such a cylindrical brush means, sweeping contact of brush filaments with a surfacebeing cleaned produces bending or flexing of the brush filaments in a direction generally parallel to the plane of the brush strip member, or transverse to the axis of rotation. Such flexing produces lever-like forces or stresses acting on the core retainer element for the brush'filaments in the brush strip member, and such forces tend to act in a ratchet-like manner to incrementally displace the core element longitudinally of the brush strip member. In otherwords, as a brush filament flexes, a portion of the filament passing beneath the wire element tends to impart a lifting force component to the core element. Since the lifting component may not be in a direct radial direction, a

small longitudinal force component is imparted'to the core element. As these longitudinal force components of the several filaments progressively act in the same direction along the length of the core element 'as successive filaments contact a surface during rotation of the cylindrical brush means, and progressive relief of such longitudinalforce components occurs when a brush filament is out of contact with the surface being cleaned, it will be apparent that each brush filament may act as a lever upon the core element and the plurality of filaments so acting produces a ratchet-like effect on the core element. Thus, when the core element is a single wire of uniform cross-section, and each brush filament is in frictional contact with such single wire,such ratchet action produced by the sweeping operation ultimately longitudinally displaces the core element so that one end of the core element begins to project from an end of the brush memher and bristles or brush filaments at the opposite end portion of a brush means are loosened and will be released.

Various prior proposed devices have been employed for preventing relative longitudinal movementof a core element in a brush strip member prior to forming in a circular or helical arrangement. Some prior proposed devices are described in Patents 2,977,622 and 2,943,051.

In each of these patents, locking devices for the core are provided in the form of a plurality of spaced locking clips or sleeves secured to the core element either by friction or in some instances by soldering or brazing. Such prior proposed devices have not'satisfactorily prevented longitudinal displacement of'the core element after the helical brush means is formed and during operation of the brush means because during formation of a helical brush strip means, the locking clips are somewhat loosened from the single core element because of stretching ofthe core element during formation of: the helix.

3,137,021 Patented June 16, 1964 ice The present invention contemplates a novel brush strip constructionin which longitudinal displacement of a retainer element for the brush filaments is positively prevented and wherein additional manufacturing operations of adding locking clips and securing the same to the core element are eliminated. The present invention contemplates a brush strip construction wherein a retainer element comprises a two strand twisted wire to provide alternate disposition of the major dimension of the wire throughout the length of the wire and the brush strip construction. Thus, the twist of the two strand wire element first disposes the major dimension of the two strand wire in vertical relation to the brush strip member and then in longitudinal spaced relation disposes the .major dimension transverse to the brush strip member. It has been found that such a two strand twisted wire retainer element is positively locked against longitudinal displacement in a brush strip member during operation and that such two strand wire retainer element does not mate riall-y afiect or limit the quantity or the amount of brush filament material which may be desired to be contained within a selected length of brush strip member.

A primary object of this invention therefore is to disclose and provide a novel brush strip construction which solves the above mentioned problems of prior brush strip 7 means in a novel, simple manner.

An object of the invention is to disclose and provide a novel brush strip construction employing a retainer element having in cross-section a major dimension and a minor dimension, the major dimension being progressively (or intermittently) turned about the axis of the retainer element so as to continuously progressively (or intermittently) change the disposition of'the metal of the retainer element with. respect to the brush strip. member.

Another object of the invention is. tov disclose and pro vide in combination with a channel-shaped'brush strip member and brush filament material carried by said brush strip. member, a two strand twisted'wire retainer element which cooperates with said strip. member and filament in a manner such that longitudinal displacement of the retainer element is prohibited during a sweeping operation.

a filament retainer element therein, and which provides positive means for prohibiting longitudinal displacement of a retainer element.

Various other objects and advantages of the present invention will be readilyapparent to those skilled in. the art from the following description of the drawings in which an exemplary embodiment of the invention is shown.

In the drawings: 7

FIG. 1 is. a fragmentary sectional view of a cylindrical brush means showing a helical arrangement of a brush strip construction embodying this invention, the section being taken longitudinally of the brush means.

FIG. 2 isa. fragmentary enlarged side view, partially in section, of the brush strip shown in FIG. 1;.

FIG. 3 is an enlarged sectional view taken in the plane indicated by line IH-YIII of FIG. 2.

FIG. 4 is an enlarged sectional view taken in the plane indicated by line lYI V of FIG. 2

FIG. 5 is a fragmentary side view of a retainer element embodying a modification of the invention.

FIG 6 is a sectional view taken. in the plane indicated by line VIVI of FIG. 5. y,

In the drawings the illustration of bristle filaments is hemtaic n exe p y y- In the drawings, an exemplary helical-brush means 10; maycomprise a brush; strip construction or member 3 11 embodying this invention. The brush means 10 provides a brush construction of cylindrical form having an axis 12 of rotation. Such a helical brush means may be readily formed by the apparatus and method shown in application Serial No. 119,869, said application Serial No. 119,869 and the present application being owned by the same assignee. It will be understood that while a helical brush means is disclosed herein by way of example, that the present invention will be also applicable to a cylindrical brush means formed of a plurality of circular brush strip members because of the constant working of the filaments on the retainer element, and that the invention has advantages and utility in brush strip members which are not curved as the present example.

The brush strip member 11 may comprise a channelshaped metal brush strip member having spaced side walls 14 joined by a bottom wall 15, said side walls 14 defining a top longitudinally extending opening 16 from which may project brush filament material 17 carried by member 11. The general channel-shaped Configuration of the brush strip member 11 may be varied in form and, in this example, side walls 14 may be provided with a plurality of longitudinally spaced inwardly directed indentations 18 at outer longitudinal edge portions of each side wall and in spaced relation'to the retainer element 19, such indentations being described in copending application Serial No. 119,869. The brush filament material 17 may comprise any desired brush material including synthetic fibers, natural fibers or metal bristles. The present invention is particularly useful when synthetic fibers are employed because of the relatively slippery, smooth external surfaces of such fibers which tend to reduce friction between the fibers and

walls

14 and 15 of the strip member. It will be understood that the amount or quantity of brush filament material 17 to *be carried by brush strip member 11 with a unit of length of member 11, may be preselected so as to provide a desired brush filament density.

The retainer element 19 comprises a two strand twisted wire element of a construction similar to that produced for various industrial purposes such as fencing and the like. The size or gauge of each strand of wire may be selected in relation to the thickness of the brush filament material and the amount of space available between

walls

14 and 15. Thus, depending upon the quantity and density of filament material required and the dimensions of the brush strip member, the retainer element-19 may be selected as to wire gauge, for example, from gauge 9 to 18.

The two strand twisted wire retainer element 19 may be twisted to any selected pitch; a suitable twisted strand may have a pitch of one turn in l or 2". The closer or smaller the pitch, the more resistance there will be to longitudinal displacement of the retainer element during sweeping with the brush means.

The two strand Wire retainer element has, in crosssection, a major dimension as indicated at m' and a minor dimension as indicated at n. In the present example of a two strand wire, it will be apparent that the major dimension is approximately twice that of the minor dimension. It will be understood, of course, that in place of a two strand twisted wire, a metal bar or strip (see FIG. having an ovoidal cross-section with a major and minor dimension may also be employed and that such a bar may be twisted about its axis throughout its length to provide turning or twisting of the major dimension about such axis in order to dispose the metal of the retainer element in progressively varying positions or attitudes with respect to the brush strip member. It will be apparent that the twisted two strand wire disposes its major dimension in alternate relation at 90 intervals along the length of the retainer element 19. As best seen in FIG. 13, it will be apparent that when the major dimension lies parallel to or along a longitudinal plane bisecting the .brush strip member and between the sidewalls 14 that V folded portions 22 of the brush filament material forming bights are compressed or deformed at the bottom wall of the brush strip member as at 23. When the major dimension is disposed transversely of this longitudinal bisecting plane, or transverse to the side walls 14, it will be apparent that, adjacent side walls 14, portions 24 of the brush strip filaments aredeformed to a greater extent than their connecting portions 23. The brush filament material is thus, firmly locked within the brush strip member and the retainer element is immovably locked relative to the member 11.

It is understood that in fabrication of brush strip member 11 a selected amount of brush filament material is uniformly distributed along an unfolded unit of length of the brush strip member, the twisted two strand wire element laid thereover, and when the brush strip member is initially folded and crimped into channel shape the side walls are brought into converging grasping relation with respect to the brush filament material; the twist or changing disposition of the metal in the cross-section of the wire retainer element will positively retain and lock the brush filament material and element in the brush strip member.

In a straight section of the brush strip member, the twisted retainer element may not be subject to longitudinal force components which may tend to act as a ratchet to displace the retainer element since the flexing of the brush filaments is normally in a direction transverse to the axis of the core element. However, when the brush strip element is disposed so that the flexing of the brush filaments are in a direction parallel to the axis of a core element,

v then the ratchet-like forces acting on a core element become effective to produce force components tending to longitudinally displace the retainer element. The two strand twisted retainer element 19 effectively serves to resist such longitudinal displacement because of the variation in interlocking compressive forces made when the side walls 14 are converged and crimped about the brush filament material and the retainer element. The alternate disposition of the major dimension of element 19 provides alternating or progressively changing stop means on element 19 to prohibit displacement of the element. Such blocking against longitudinal displacement of the retainer element 19 is further enhanced by curving the brush strip member into circular form, or, into the continuous helical strip often used in street sweeping and industrial brush means. When the brush strip member is curved about a mandrel and at the same time the two strand retainer element 19 is curved about the mandrel in its assembled relation with the brush strip member and the brush filaments, the alternate disposition in a curvilinear path of the major dimension of the retainer element provides an additional restraining effect upon the core element and the wire retainer element is positively prevented from longitudinal displacement.

It will thus be apparent to those skilled in brush making that the retainer element, formed with a major and minor dimension and with said dimensions alternately arranged throughout the length of the element, positively cooperates with the brush filament material and the brush member to prohibit relative movements of the retainer element, brush filamentsyand brush member during operating conditions whether severe or normal. Longitudinal displacement of the retainer element after formation of the brush means is effectively and simply prevented.

While the retainer elements of FIGS. 2 and 5 exemplarily illustrate a relatively uniform pitch or twist, it is contemplated that the twist in such bar stock may occur .in ashort section of the element, that is, a rapid twist is made. Between such short twisted sections, relatively long straight non-twisting sections may be provided in alternate vertical and horizontal relation. In addition, a wire or bar stock of suitable cross-section, such as circular or square, may be deformed as by horizontal and vertical pressure rolls to provide alternate dispositions of major and minor dimensions of deformed portions of the bar stock. i

It will be understood that the twist or pitch of the retainer element may occur in random fashion with respect to the'indentations in the walls 14, in other words, the spacing of the indentations is not necessarily related to the twist of the retainer element and an indentation may occur opposite horizontal or vertical dispositions of the retainer element.

All modifications and changes of the retainer element and the brush construction disclosed herein and coming within the spirit of the invention and scope of the claims appended hereto are embraced thereby.

I claim:

1. A brush strip construction comprising: a curved, channel-shaped member having spaced side walls and a bottom Wall; a retainer element consisting essentially of only two twisted strands Within said channel-shaped member having a selected pitch to alternately present distinct major and minor diameters and curved therewith; and brush filaments folded in said member between said walls and said retainer element; the twist of the two strand retainer element being cooperable with said brush filaments and said channel-shaped member to'frictionally retain said element against longitudinal movement relative to said channel-shaped member.

2. In a brush strip means, the provision of: a channelshaped member having side walls in spaced relation to a longitudinal plane bisecting said member and passing between said side walls; brush filament material carried by said channel-shaped member; and a retainer element separate from said brush filament material and carried in said member for frictionally retaining the filament material in the member, said retainer element having in to said longitudinal plane whereby longitudinal movement of the retainer element relative to said filament material and member is inhibited.

3. In combination with a brush strip member and brush filament material carried by said member, the provision of: a retainer element separate from said filament material and member and having major and minor dimensions in cross-section, said major dimension being disposed in alternate 90 relation at spaced intervals to restrain relative longitudinal movement of the element with respect to the filament material and the member.

4. In combination with a brush strip member and brush material carried by said member, the provision of: 3.

retainer element separate from the member and brush 'material having in cross-section a major dimension which is at least substantially twice that of a minor dimension ii thereof; said major dimension being progressively turned about the longitudinal axis of the element for restraining longitudinal displacement of said retainer element with respect to said brush strip member.

5. In combination with a brush strip member and brush filament material carried by said member; a twisted wire retainer element consisting essentially of only two strands within and overlying said member, said retainer element being within a fold of said brush material.

6. A brush strip means comprising in combination: a brush strip member having side walls and a bottom wall defining a longitudinal channel; brush filaments extending outwardly from said channel and having a folded portion in said channel; a retaining element lying in said folded portion and cooperable with said side and bottom walls to hold said brush filaments in said chamber, said retaining element having means restraining longitudinal movement of the element relative to the walls and filament, said restraining means including an elongated crosssectional disposition of metal presenting major and minor dimensions throughout the length of the retainer element, and said element being turned about its longitudinal axis to alternately position said major and minor dimensions whereby said retainer element is alternately locked with respect to said brush filamentsand side walls and said brush filaments and bottom wall.

7. A brush strip means comprising: a channel-shaped member having substantially opposite facing side walls joined together by a bottom wall; a plurality of brush filaments; each brush filament having a folded portion which forms a bight snugly disposed within said channelshaped member; a retainer element separate from the brush filaments and disposed within the bights; said re tainer element consisting essentially of only two twisted wires which are in substantially continuous engagement with one another so as to present a single major dimension at least substantially twice the size of a single minor dimension as seen in consecutive transverse cross-sections of the retainer element, whereby at transverse cross-sections said bights are significantly flattened along the major dimensions to prevent movement of the retainer element relative to said brush filaments.

References Cited in the file of this patent Germany Nov. 3, 1 930

Claims

5. IN COMBINATION WITH A BRUSH STRIP MEMBER AND BRUSH FILAMENT MATERIAL CARRIED BY SAID MEMBER; A TWISTED WIRE RETAINER ELEMENT CONSISTING ESSENTTIALLY OF ONLY TWO STRANDS WITHIN AND OVERLYING SAID MEMBER, SAID RETAINER ELEMENT BEING WITHIN A FOLD OF SAID BRUSH MATERIAL.