A bristle for use in a railway roadbed broom is disclosed. The bristle is made of an elongate elastomeric core member with two elastomeric skin members bonded around it. pieces of reinforcing stranded material are used to strengthen the interfaces between the elastomeric members.
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1. A roadbed cleaning solid reinforced elastomeric elongate bristle having at least a first elongate elastomeric member, a second elongate elastomeric member distinct from the first elongate elastomeric member and a first piece of reinforcing stranded material; and wherein said first elongate elastomeric member and second elongate elastomeric member are bonded together with said first piece of reinforcing stranded material therebetween, and said first piece of reinforcing stranded material is further from a bristle center of gravity axis than from the nearest external surface of the bristle, and wherein said first elongate elastomeric member includes a curved external surface extending between two noncontiguous boundary portions.
20. An invention comprising a road bed cleaning solid reinforced elastomeric elongate bristle including:
elastomeric material having a cross-section with an external u-shaped sweeping curve and an external trailing straight line connecting tops of said u-shaped sweeping curve, said u-shaped sweeping curve being part of an external sweeping surface extending lengthwise on the bristle; and a first piece of reinforcing stranded material disposed further from a cross-section center of gravity than from the nearest external surface of the bristle and a portion of said first piece of reinforcing stranded material following the contours of said external sweeping surface with elastomeric material between said portion of said first piece of reinforcing stranded material and said external sweeping surface.
29. An invention comprising a plurality of road bed cleaning solid reinforced elastomeric bristles mounted to a rotary sweeper core, each bristle having:
a core portion made of elongate elastomeric material; a skin portion made of elongate elastomeric material; and a first piece of reinforcing stranded material marking off said core portion and said skin portion; and wherein said skin portion has an external sweeping surface and wherein said first piece of reinforcing stranded material is further from a cross-section center of gravity than from the nearest external surface of the bristle wherein said external sweeping surface of each bristle is u-shaped in cross-section and a cross-section of each bristle at least somewhere along its length has said first piece of reinforcing stranded material extending in a u-shape between two noncontiguous end points.
4. A roadbed cleaning elongate bristle having at least a first elongate elastomeric member, a second elongate elastomeric member distinct from the first elongate elastomeric member and a first piece of reinforcing stranded material; and wherein said first elongate elastomeric member and second elongate elastomeric member are bonded together with said first piece of reinforcing stranded material therebetween, and said first piece of reinforcing stranded material is further from a bristle center of gravity axis than from the nearest external surface of the bristle, and wherein said bristle further includes a third elongate elastomeric member bonded to said second elongate elastomeric member with a second piece of reinforcing stranded material therebetween, and said third elongate elastomeric member is distinct from said first and second elongate elastomeric member.
33. A process for making road bed cleaning solid reinforced elastomeric sweeper bristles having:
a core portion made of elongate elastomeric material; a skin portion made of elongate elastomeric material; and a first piece of reinforcing stranded material marking off said core portion and said skin portion; and
wherein said skin portion has a curved external sweeping surface which extends between two noncontiguous boundary portions and wherein said first piece of reinforcing stranded material is further from a cross-section center of gravity than from the nearest external surface of the bristle, the steps comprising: placing said first piece of reinforcing stranded material between said skin portion and said core portion, and curing said skin portion and said core portion together into a solid mass with said first piece of reinforcing stranded material therebetween. 7. An invention for use in cleaning a roadbed comprising an elongate bristle having at least a first elongate elastomeric member, a second elongate elastomeric member distinct from the first elongate elastomeric member and a first piece of reinforcing stranded material; and wherein said first elongate elastomeric member and second elongate elastomeric member are bonded together with said first piece of reinforcing stranded material therebetween, and said first piece of reinforcing stranded material is further from a bristle center of gravity axis than from the nearest external surface of the bristle, and wherein said first elongate elastomeric member is u shaped in cross-section and said second elongate elastomeric member fills the inside of the u, and said first piece of reinforcing stranded material is coextensive with the interface between said first elongate elastomeric member and second elongate elastomeric member.
11. A process for making sweeper bristles, the steps comprising, in order:
(a) lining an elongate cavity of a mold with an elastomeric lining having a concave portion, (b) installing a first piece of reinforcing stranded material into the concave portion of said elastomeric lining, (c) inserting an elongate elastomeric core member into the concave portion of said elastomeric lining, (d) installing a second piece of reinforcing stranded material on top of said elongate elastomeric core member, (e) placing an elastomeric layer on top of said second piece of reinforcing stranded material, (f) heating the mold contents, thereby forming a bristle by the bonding of said elastomeric lining to said elongate elastomeric core member with said first piece of reinforcing stranded material therebetween and the bonding of said elongate elastomeric core member to said elastomeric layer with said second piece of reinforcing stranded material therebetween.
3. An invention for use in cleaning a roadbed comprising an elongate bristle having at least a first elongate elastomeric member, a second elongate elastomeric member distinct from the first elongate elastomeric member and a first piece of reinforcing stranded material; and wherein said first elongate elastomeric member and second elongate elastomeric member are bonded together with said first piece of reinforcing stranded material therebetween, and said first piece of reinforcing stranded material is further from a bristle center of gravity axis than from the nearest external surface of the bristle, and wherein said first elongate elastomeric member includes a cylindrically curved external surface extending between two noncontiguous boundary portions, and said first stranded material reinforcing piece includes a cylindrically curved portion, and said bristle has a generally flat surface opposite said cylindrically external surface of said first elastomeric member.
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1. Field of the Invention
This invention relates to a bristle for a broom and method of making the bristle. More specifically, this invention relates to a bristle for use in a railroad bed or track.
2. Description of the Prior Art
The use of bristles for a broom machine adapted for cleaning a railway road bed or track is well known to the art. Generally, such bristles are mounted on a rotary sweeping element and are commonly used for sweeping ballast and other debris along the railway track.
The ballast is usually a thick layer of crushed limestone which is placed between and along side of the rails. Preferably, the top service of the ballast should be level with or slightly below the railway ties. Unfortunately, when new ballast is dumped onto a railway roadbed, the ballast is not properly and evenly distributed. There may be spaces between rails which are not properly filled in with ballast. Additionally, the rails, which should be free of loose ballast, may be at least partially covered by ballast.
In order to evenly distribute the ballast and clear ballast from the tops of the railway ties, it is known to use rotary sweeping cores. However, because of the extremely harsh wear on the bristles commonly mounted, to such cores, the bristles are subject to breakage if they do not yeild properly. Additionally, as will be readily appreciated, the limestone or similar ballast will cause an extreme amount of wear on the bristle elements.
Among prior art Patents, my previous U.S. Pat. No. 3,237,232, issued on Mar. 1, 1966, discloses the use of hollow, resilient tube-like bristles on a rotary sweeper core. The generally hollow bristle element is mounted to a rotary sweeping core by an elongate stiffner element extending into the interior of the bristle.
The patent to Kershaw et al., U.S. Pat. No. 3,649,984, issued on Mar. 21, 1972, discloses a bristle element having a core made of a bundle of parallel straight springsteel spines or wires incased in a resilent sheath.
The Price U.S. Pat. No. 4,184,223, issued on Jan. 22, 1980, discloses a sweeper bristle element having a knob at one end. Additionally, a nylon or similar reinforcing material reinforces the solid elastomeric stem to which the knob is attached.
Although the prior art bristles have been generally useful, they have been subject to a number of significant disadvantages. Specifically, the longer lasting of the prior art bristles have often been complex in construction and expensive to manufacture. Those prior art bristles which may be made inexpensively and efficiently are generally prone to wearing out and/or breaking.
Accordingly, it is an object of the present invention to provide a railway roadbed bristle which is simple in construction.
A further object of the present invention is to provide a railway roadbed bristle of elastomeric material and configured to minimize the risk of breakage.
Yet another object of the present invention is to provide a railway roadbed bristle designed to accomodate a great deal of use before wearing out.
Yet another object of the present invention is to provide a method for making railway roadbed bristles which is inexpensive, and efficient.
These and other objects of the present invention which will be apparent as the description proceeds are accomplished by providing an elongate bristle having at least a first elongate elastomeric member, a second elongate elastomeric member distinct from the first elongate elastomeric member and a first piece of reinforcing strand material. The first elongate member and second elongate member are bonded together with the first piece of reinforcing stranded material there between. The first piece of reinforcing stranded material is further from a bristle center of gravity axis than from the nearest external surface of the bristle. The bristle further includes a third elongate elastomeric member bonded to the second elongate elastomeric member with a second piece of reinforcing stranded material there between. Preferably, the first elongate elastomeric member is U shaped in cross section and the second elongate elastomeric member fills the inside of the U. Preferably, the cylindrically curved external surface corresponding to the base of the U serves as a sweeping surface when the bristles are mounted on a rotary sweeping core.
As clearly shown in FIG. 2, the elastomeric material of member 18 which constitutes a skin portion of the bristle 10 has a cross section with the external U shaped sweeping curve. The U-shaped sweeping curve is a part of the external sweeping surface 18B extending lengthwise on the bristle. The reinforcing stranded material piece 17 clearly follows the contours of the external sweeping surface 18B with elastomeric material between the external sweeping surface and the reinforcing stranded material 17.
As mentioned above, the first piece of reinforcing stranded material 17 has a cross section (FIG. 2) which extends in a U shape between two noncontiguous end points. Further, the reinforcing stranded material piece 14 is disposed in a line (as viewed in cross section of FIG. 2) which line is parallel to and just underneath the external trailing straight line defined by trailing or following surface 12F taken in cross section.
The elongated elastomeric members 12, 16, and 18 are distinct in that they are marked off from each other by the stranded reinforcing material. As is discussed in detail below, they are a solid mass of rubber which is commonly cured with the reinforcing stranded material between a skin portion of the bristle including members 12 and 18 and a core portion of the bristle constituted by member 16.
An important aspect of the present invention is the use of reinforcing stranded material which is near the external surfaces of the bristle 10. More specifically, as shown in FIG. 2, the pieces of reinforcing stranded material 14 and 17 are further from the center of gravity axis (labeled C. G.) than from the nearest external surface of the bristle. By installing the reinforcing stranded material near the surface of the bristle, the strength of the reinforcing stranded material in tension will prevent premature cracking and breaking of the bristle at the point of maximum bending stress. Additionally, this reinforcing stranded material installed near the surface will provide greater stiffness of the bristles leading to better sweeping action.
In addition to the placement of reinforcing stranded material near the surface of the bristle, the present invention is especially advantageous in the shape and contours of the individual pieces making up the bristle element 10. More specifically, the U shaped interior surface of skin or first elongate elastomeric 18 is especially advantageous in cooperating with the reinforcing stranded material 17 to distribute any stresses caused by the bristle hitting a piece of ballast or similar debris. The contours at the interface between core member 16 and skin member 18 causes any such stresses to be distributed throughout a wide area thereof. The third elongate elastomeric or skin member 12 is bonded to the curved skin member 18, thereby allowing some of the stress on curved skin member 18 to be transmitted to the backside of core member 16 by way of flat skin member 12 and reinforcing material 14 disposed in between flat skin member 12 and the core member 16. Further, the use of a curved leading or sweeping surface 18B is advantageous in providing a sideways (into or out of the plain of FIG. 3) component to the velocity imparted to the ballast material 34T. This will tend to evenly distribute the ballast throughout the width of the roadway track, instead of merely throwing it along the length of the track. The cylindrically curved sweeping surface 18B is especially adapted to hold up for a long period of use under harsh conditions.
Turning now to FIG. 4, a method of making a bristle will presently be discussed. A mold 50 having a series of elongate cavities 52 separated by walls 54 is initially lined with a elastomeric lining 28. Preferably, a separate piece of elastomeric lining 28 is placed in each of the series of generally parallel elongate cavities. Each piece of elastomeric lining 28 is U-shaped with a concave portion. Note that those numbers in FIG. 4 in the 20 series generally correspond by a difference of 10 to the numbers of FIG. 1 and FIG. 2 in the 10 series. For example, the elastomeric lining 28 will correspond to the first elongate elastomeric member 18 in the bristle 10 produced by the process of molding illustrated in FIG. 4.
Following the lining of the mold cavity with elastomeric lining, a first piece of reinforcing stranded material 27 is distributed throughout a plurality of the mold cavities 52 as shown. An elongate elastomeric core member 26 is inserted into the concave portion of the elastomeric lining 28. A second piece of reinforcing stranded material 24 is then installed on top of the elongate elastomeric core member, the reinforcing stranded material 24 extending over a number of the similarly situated core members 26. Next, an elastomeric layer is placed on top of the second piece reinforcing stranded material, the elastomeric layer also extending throughout or over several of the mold cavities 52. The loaded mold should now be placed in a molding machine which consists of upper and lower heated plates arranged to provide a clamping force on the mold of about 120 pounds per square inch which presses the raw rubber or similar elastomeric material and the nylon or similar reinforcing stranded material into a solid mass in the mold and heat cures the raw rubber into a solid section securely bonding the rubber and reinforcing material in about one hour of curing time. Upon completion of the curing period the mold pressure is released and the mold is removed. As will be readily appreciated, the mold product will be a plurality of elongate portions joined by relatively thin portions, the relatively thin portions corresponding to the walls 54 in between the mold cavities 52. Next, the mold product may be cut at each thin portion, thereby dividing the mold product into a plurality of separate elongate pieces. Although each elongate piece may constitute a sweeper bristle, it is preferred to practice the present inventive process with twelve feet along elongate pieces which may then be cut into twelve or eighteen inch lengths before use as bristles. Preferably, the machine used to make these bristles is a truck tread molding machine which will accept a mold twelve feet long by two feet wide by three inches thick and heat to various temperature ranges well-known in the art. After cutting the mold product along the thin portions, one will obtain twelve elongate pieces, each being twelve feet long and suitable for cutting into a plurality of bristles, the number of bristles being dependent upon the desired length.
Although the various elastomeric members and pieces of the present invention are preferably made of rubber and the reinforcing stranded material is preferably a fabric such as nylon, it will be readily appreciated that the present invention is not so limited except where otherwise noted in the appended claims. More geneally, although specific constructions, steps and features have been discussed in detail, it is to be readily appreciated that these are for illustrative purposes only. Various changes and modifications will readily occur to those of ordinary skill in the art and, accordingly, the scope of the present invention should be determined by reference to the appended claims.
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| Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
| Jun 13 1983 | HOLLEY, JOHN D | HOLLEY ENGINEERING COMPANY, INC , MONTGOMERY,A CORP OF AL | ASSIGNMENT OF ASSIGNORS INTEREST | 004202 | /0888 | |
| Jun 17 1983 | Holley Engineering Company, Inc. | (assignment on the face of the patent) | / | |||
| Jul 15 1996 | HOLLEY ENGINEERING CO , INC | Harsco Corporation | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 008231 | /0813 | |
| May 01 1998 | Harsco Corporation | Harsco Technologies Corporation | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 009197 | /0680 |
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