COMPOSITE ABRASIVE ATTACHMENT ARTICLE FOR CONCRETE POWER TROWEL MACHINE

Abstract

The invention provides a float trowel blade attachment for cement floor finishers comprising a rectangular section of sheet metal having a top surface and a bottom surface and having its edges optionally bent upwardly, means for providing to the top surface a three-sided rearwardly open pocket on the back of the section adjacent the leading edge thereof adapted to partially receive a finish trowel blade of the finisher, a spring clip secured to the top surface or the pocket-forming means and extending rearwardly therefrom so as to be engageable with the finish trowel blade to retain the section thereon, and wherein said rectangular sheet metal has attached to its bottom surface using an adhesive or mechanical attachment material interlayer, a composite rigid abrasive element bonded to a resilient backing and wherein said abrasive element comprises a substrate of two or more non woven layers pads including holes for inserting grinding and polishing elements.

Claims

1. A float trowel blade attachment for cement floor finishers comprising a rectangular section of sheet metal having a top surface and a bottom surface and having its edges optionally bent upwardly, means for providing to the top surface a three-sided rearwardly open pocket on the back of the section adjacent the leading edge thereof adapted to partially receive a finish trowel blade of the finisher, a spring clip secured to the top surface or the pocket-forming means and extending rearwardly therefrom so as to be engageable with the finish trowel blade to retain the section thereon, and wherein said rectangular sheet metal has attached to its bottom surface using an adhesive or mechanical attachment material interlayer, a composite rigid abrasive element bonded to a resilient backing and wherein said abrasive element comprises a substrate of two or more non woven layers pads laminated together with an adhesive interlayer said non woven pads including holes that are die-cut through the thickness of the pad to provide apertures for inserting grinding and polishing elements.

2. In combination with a cement floor finisher having one or more finishing trowel blades mounted for rotation thereon and adapted to be moved over a floor to be finished, corresponding float trowels underlying the finish trowel blades, said float trowels having rearwardly open pockets formed thereon adjacent the leading edges thereof partially rcceiving the finish trowel blades, means on the float trowels for releasably retaining the float trowels on the finish trowel blades, wherein said float trowel includes attached to its bottom surface using an adhesive or mechanical attachment material interlayer, a composite rigid abrasive element having a resilient backing bonded to said bottom surface and wherein said rigid abrasive element comprises a substrate of two or more non woven layers pads laminated together with an adhesive interlayer said non woven pads including holes that are die-cut through the thickness of the pad to provide apertures for inserting grinding and polishing elements.

3. A float trowel for cement floor finishers comprising a rectangular section of sheet metal having a top surface and a bottom surface and optionally having its leading edge and its side edges bent upwardly, means providing upright surfaces on the upper side of said section arranged to engage the leading edge and end edges of a finish trowel of a cement floor finisher so that said section can be held against lateral displacement with respect to the finish trowel by said surfaces, a rearwardly extending spring clip secured to said section extending rearwardly over the upper surface of said section so as to be engageable with the finish trowel to retain said section thereon and wherein said metal sheet has attached to its bottom surface using an adhesive or mechanical attachment material interlayer, a composite rigid abrasive element bonded to a resilient backing and wherein said rigid abrasive element comprises a substrate of two or more non woven layers pads laminated together with an adhesive interlayer said non woven pads including holes that are die-cut through the thickness of the pad to provide apertures for inserting grinding and polishing elements.

4. The float trowel blade attachment of claim 1, wherein said adhesive is a thermoset adhesive.

5. The float trowel blade attachment of claim 1, wherein said mechanical attachment material interlayer uses a hook and loop means.

6. The float trowel blade attachment of claim 1, wherein said abrasive element includes diamond particles as the abrasive.

7. The float trowel blade attachment of claim 1, wherein said abrasive element includes cubic boron nitride.

8. The float trowel blade attachment of claim 1, wherein said abrasive element includes boron carbide.

9. The float trowel blade attachment of claim 1, wherein said abrasive element includes titanium carbide.

10. The float trowel blade attachment of claim 1, wherein said abrasive element includes silicon carbide.

11. The float trowel blade attachment of claim 1, wherein said abrasive element includes zirconia.

12. The float trowel blade attachment of claim 1, wherein said abrasive element includes fused aluminum oxide.

13. The float trowel blade attachment of claim 1, wherein said composite rigid abrasive element includes fired agglomerated abrasive particles.

14. The float trowel blade attachment of claim 1, wherein said non woven layers include polyester fibers.

15. The float trowel blade attachment of claim 1, wherein said non woven layers include nylon fibers.

16. The float trowel blade attachment of claim 1, wherein said non woven layers include polypropylene fibers.

17. The float trowel blade attachment of claim 1, wherein said non woven layers include rayon fibers.

18. The float trowel blade attachment of claim 1, wherein said non woven layers include acrylic fibers.

19. The float trowel blade attachment of claim 1, wherein said non woven layers include glass fibers.

20. The float trowel blade attachment of claim 1, wherein said non woven layers include mixtures of polyester and polypropylene fibers.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0018] FIG. 1 is a bottom view of a conventional motorized rotational troweling machine with the composite abrasive article of the invention attached to the trowel blades.

[0019] FIG. 2 illustrates the composite abrasive article having the rigid abrasive elements.

[0020] FIG. 2A is a photo showing the composite abrasive article having the rigid abrasive elements.

[0021] FIG. 3 shows the composite abrasive article comprises rigid abrasive elements of FIG. 2 bonded to a resilient backing.

[0022] FIG. 3A illustrates a photo showing the composite abrasive article comprising rigid abrasive elements of FIG. 2 bonded to a resilient backing.

[0023] FIG. 4 shows the back of a float trowel metal blade with mechanical attachment interlayer. FIG. 4A is photo of a prototype metal plate with a mechanical attachment interlayer.

[0024] FIG. 5 and FIG. 5A is a perspective view of one of the float trowels embodying the present invention in a position wherein it is about to be mounted/applied to one of the finish trowel blades of the cement floor finisher.

[0025] FIG. 5B is a photo of the float throwel shown in FIG. 5A.

[0026] FIG. 6 shows the adhesive backing or mechanical (velcro) backing that is attached to the float trowel as well as the resilient backing having abrasive particles that are part of the invention.

[0027] FIG. 6A illustrates the novel product of the invention wherein the floating blade has incorporated therein the adhesive layer and composite abrasive element.

[0028] FIG. 7 illustrates the composite abrasive attachment assembly mounted on trowel blade.

[0029] FIG. 8 shows the composite abrasive attachment articles installed on a trowel machine.

[0030] FIG. 9 is a prototype photo of the embodiment of FIG. 8.

[0031] FIG. 10 is an alternate embodiment to the one of FIG. 3 showing a two layer substrate having openings for placing circular abrasive elements.

[0032] FIG. 11 shows the two layer substrate including the abrasive element placed in the opening of the substrate.

SUMMARY OF THE INVENTION

[0033] The instant invention provides a composite abrasive article having rigid abrasive elements bonded to a resilient backing. The rigid abrasive elements are further attached to a metal plate using an adhesive or mechanical attachment material interlayer. Suitable metal plates are described in the concrete finishing industry as “float” blades.

[0034] The composite abrasive attachment assembly includes mechanical mounting features to attach the composite abrasive assembly onto an existing concrete power trowel blade.

[0035] One or more composite abrasive attachment articles may be installed and removed from each of the trowel machine blades without requiring disassembly of the power trowel blades from the machine trowel head.

[0036] The composite abrasive attachment article may be utilized with hand-held, walk-behind, or ride-on power trowel machines.

[0037] The invention also provides a float trowel blade attachment for cement floor finishers comprising a rectangular section of sheet metal having a top surface and a bottom surface and having its edges optionally bent upwardly, means for providing to the top surface a three-sided rearwardly open pocket on the back of the section adjacent the leading edge thereof adapted to partially receive a finish trowel blade of the finisher, a spring clip secured to the top surface or the pocket-forming means and extending rearwardly therefrom so as to be engageable with the finish trowel blade to retain the section thereon, and wherein said rectangular sheet metal has attached to its bottom surface using an adhesive or mechanical attachment material interlayer, a composite rigid abrasive element bonded to a resilient backing.

[0038] The invention further provides in combination with a cement floor finisher having one or more finishing trowel blades mounted for rotation thereon and adapted to be moved over a floor to be finished, corresponding float trowels underlying the finish trowel blades, said float trowels having rearwardly open pockets formed thereon adjacent the leading edges thereof partially rcceiving the finish trowel blades, means on the float trowels for releasably retaining the float trowels on the finish trowel blades, wherein said float trowel includes attached to its bottom surface using an adhesive or mechanical attachment material interlayer, a composite rigid abrasive element having a resilient backing bonded to said bottom surface.

[0039] The invention also provides a float trowel for cement floor finishers comprising a rectangular section of sheet metal having a top surface and a bottom surface and optionally having its leading edge and its side edges bent upwardly, means providing upright surfaces on the upper side of said section arranged to engage the leading edge and end edges of a finish trowel of a cement floor finisher so that said section can be held against lateral displacement with respect to the finish trowel by said surfaces, a rearwardly extending spring clip secured to said section extending rearwardly over the upper surface of said section so as to be engageable with the finish trowel to retain said section thereon and wherein said metal sheet has attached to its bottom surface using an adhesive or mechanical attachment material interlayer, a composite rigid abrasive element bonded to a resilient backing.

DETAILED DESCRIPTION OF THE INVENTION

[0040] The composite abrasive article comprises rigid abrasive elements bonded to a resilient backing. The rigid abrasive elements contain diamond or other suitable abrasive particles held together with resin, ceramic, metal, or combinations thereof. The abrasive particles may be of specific composition and size to facilitate grinding, honing, polishing, and burnishing of hard concrete surfaces. The resilient backing may be woven cloth, foam, felt, nonwoven material, or combinations thereof. The rigid abrasive elements are further attached to a metal plate using an adhesive or mechanical attachment material interlayer to form a composite abrasive attachment assembly. Suitable metal plates are described in the concrete finishing industry as “float” blades.

[0041] The composite abrasive attachment assembly includes mechanical mounting features to attach the composite abrasive assembly onto an existing concrete power trowel blade. One or more composite abrasive attachment articles may be installed and removed from each of the trowel machine blades without requiring disassembly of the power trowel blades from the machine trowel head.

[0042] The composite abrasive attachment article may be utilized with hand-held, walk-behind, or ride-on power trowel machines.

[0043] Referring to FIG. 1, the attachment 1 of the invention fixes onto the existing power trowel blade 2, facilitating the use of the power trowel for grinding and polishing hard concrete surfaces to high aesthetic quality. The replaceable attachment 1 to a trowel blade 2 may be provided with a replaceable trailing edge. The replaceable attachment which is fixed into trowel blade 2 is then attachable to a conventional motorized gear rotor 3 by attachment shafts 4. This is a bottom view that blocks view of an engine that provides rotational power to the motorized gear rotor 3 in conventional practice. Typically, a handle shaft 5 with a handle 6 houses a control shaft that can be rotated by blade-control knob 7 to cause the blade 2 with attachment 1 to be either flat against a cement surface being troweled or for an upwardly-bent leading edge 8 to be raised. A circular guard 9 may be positioned at the outside diameter of rotation of the blades with attachment to prevent their contact with outside objects when the blades with attachments are being rotated. There are also conventional riding models of motorized rotary trowel blades that function similarly in relation to the rotational features and adjustment of the angle of the blade. This invention is related to the structure attached to the blade, not the rotary mechanism or adjustment of the angle of the blades in relation to the surface of cement being troweled.

[0044] The composite abrasive article 21 of the invention includes the rigid abrasive elements 10 as shown in FIG. 2 bonded to a resilient backing 11 as shown in FIG. 3 and FIG. 3A shown as a photo of a prototype.

[0045] The rigid abrasive elements 10 contain diamond or other suitable abrasive particles held together with resin, ceramic, metal, or combinations thereof. The abrasive particles of element 10 may be of specific composition and size to facilitate grinding, honing, polishing, and burnishing of hard concrete surfaces. The resilient backing 11 may be woven cloth, foam, felt, nonwoven material, or combinations thereof. The rigid abrasive elements 10 which are bonded to the resilient backing 11 are further attached to the bottom surface of a metal plate 28 (bottom of float blade) using an adhesive or mechanical attachment material interlayer 13 as illustrated in FIG. 4 and the prototype FIG. 4A shown as a photo. Suitable metal plates are described in the concrete finishing industry as “float” blades as shown in FIGS. 5A and FIG. 5B.

[0046] As shown in FIG. 5, the finishing trowel blades may optionally have their outer and inner ends bent upwardly slightly, as indicated at 25 and 26, the side edges 27 and 47 are not so bent. This is particularly true of the trailing edge 27 which imparts the smooth finish surface to the floor as the trowels are moved thereover. The finish trowels also are usually relatively narrow, as illustrated in FIG. 5, and because of their size and the lack of the upturned side edges the finish trowels are unsuitable for performing the floating operation even though the trowels may be adjusted by a knob to assume perfectly horizontal positions.

[0047] The float trowel blade embodying the present invention as shown in FIG. 5A consists of a relatively broad section of sheet metal 47 which not only has its ends bent upwardly as indicated at 30 and 31 but also has the side edges bent upwardly as indicated at 32 and 33. It should be noted that the bents are optional. A cap 34 extends from end to end of the float trowel and may be spot welded thereto adjacent the leading edge 32. This cap extends from adjacent the leading edge toward the trailing edge 33 so as to substantially cover over the forward half of the finish trowel when the neat trowel is applied thereto. The ends of the cap may be bent downwardly, as indicated at 36, over the upwardly bent ends 30 and 31 or the finish trowel. In this manner the cap 34 cooperates with the body of the float trowel to form a rearwardly open pocket designed to receive approximately the forward half of the finish trowel. A spring clip 37 may be secured to the top of the cap such as by spot welding 38 and this spring clip is formed with a detent 39 adapted to bev snapped over the bar 17 on the finish trowel to retain the float trowel in position.

[0048] The construction of the entire attachment of the invention which includes the composite abrasive elements is fully illustrated in FIG. 6. Referring to FIG. 6, the attachment of the invention consists of three components: Component one is the device illustrated in FIG. 5A to which is attached on the bottom surface thereof the elements of FIG. 4 and FIG. 3 respectively. The device of FIG. 5A consists of a relatively broad section of sheet metal 28 having a top surface and a bottom surface optionally having its ends bent upwardly as indicated at 30 and 31 but also optionally has the side edges bent upwardly as indicated at 32 and 33. It should be noted that the bents are optional. A cap 34 extends from end to end of the float trowel and may be spot welded thereto adjacent the leading edge 32. This cap extends from adjacent the leading edge toward the trailing edge 33 so as to substantially cover over the forward half of the finish trowel when the neat trowel is applied thereto. The ends of the cap may be bent downwardly, as indicated at 36, over the upwardly bent ends 30 and 31 or the finish trowel. In this manner the cap 34 cooperates with the body of the float trowel to form a rearwardly open pocket designed to receive approximately the forward half of the finish trowel. A spring clip 37 may be secured to the top of the cap such as by spot welding 38 and this spring clip is formed with a detent 39 adapted to be snapped over the bar 17 on the finish trowel to retain the float trowel in position.

[0049] Component two is the adhesive component or mechanical attachment material interlayer 13 (such as hook and loop or VELCRO™) which is attached to bottom surface 28 of the metal.

[0050] Component three as shown in FIG. 6 is the abrasive element 21 which has abrasive elements 10 bonded to a resilient backing 11. Component three is bonded to component two whcih component includes the adhesive component or mechanical attachment means.

[0051] FIG. 6A illustrates the novel product of the invention wherein the floating blade 46 has incorporated therein the adhesive layer 13 and composite abrasive element 21.

[0052] FIG. 7 shows the the composite abrasive attachment assembly 21 mounted on a trowel blade. The composite abrasive attachment assembly includes mechanical mounting features to attach the composite abrasive assembly onto an existing concrete power trowel blade

[0053] FIG. 8 is a bottom view of a trowel machine showing the abrasive attachment of the invention 21 having abrasive elements 10 bonded to a resilient backing 11 mounted on the blades of the trowell machine. One or more composite abrasive attachment articles may be installed and removed from each of the trowel machine blades without requiring disassembly of the power trowel blades from the machine trowel head.

[0054] FIG. 9 is a photo of a prototype as shown in FIG. 8.

[0055] FIG. 10 illustrates a substrate 44 consisting of layers 40 and 41 and having openings 42 suitable for placing abrasive elements.

[0056] The substrate 44 is comprised of two or more non woven layers 40 and 41 laminated together with an adhesive interlayer. With typical single-layer non woven pads, holes are die-cut through the thickness of the pad to provide apertures for inserting secondary grinding and polishing elements. The composite nature of the laminated pad allows inclusion of certain features in the pad assembly, such as for example, blind-hole insert pockets. Such precisely-dimensioned features are not possible with a single-layer non woven pad construction. The composite pad construction further permits selection of component non woven materials for each layer having different, desirable properties. When combined in the assembled construction, each distinct layer contributes uniquely to enhance the performance of the pad assembly.

[0057] The component non woven layers may include fibers selected from, for example, polyester, nylon, polypropylene, rayon, acrylic, glass, and natural fibers. Nonwoven mat bonding materials may include, for example, latex, acrylic, and phenolic resins.

[0058] FIG. 11 illustrates a substrate 44 consisting of layers 40 and 41 and having including abrasive elements 43. The abrasive insert articles 43 are manufactured as follows: A mix of materials which include a curable resin (thermally curable or radiation curable), a silane coupling agent, a photoinitiator, a filler, thermal initiator, mineral fiber, inorganic powders and agglomerated abrasive particles are mixed together to form an abrasive slurry. The slurry components are mixed together, using an electric mixer and a four-blade impeller at 300 rpm for ˜15 minutes. or longer as required. A silicone mold is sprayed with a mold release agent and allowed to air-dry for ˜5 minutes at room temperature.

[0059] The abrasive slurry mix is then poured into the mold cavity. The mold is agitated by hand to release air bubbles from the mold surfaces and from within the slurry liquid. A nonwoven insert substrate produced as described above is placed in the mold cavity and downward pressure applied by hand to force the slurry into the lofty nonwoven face of the insert substrate.

[0060] A UVA light source is then placed on a horizontal surface with the UV bulb and reflector facing upward. The UV lamp is turned on and allowed to warm up for 15-30 minutes with the power switch set to “standby”.

[0061] The silicone mold containing the insert substrate and abrasive slurry is then placed directly onto the UV lamp shielding glass above the UV lamp bulb. The UV power source is switched on to “high.” After ˜15 seconds, the abrasive slurry which resides impregnated into the insert substrate is at least partially cured to a rigid state, and the mold is removed from over the UV lamp.

[0062] The at least partially cured abrasive insert is then removed from the silicone mold by peeling the elastomeric mold body from the insert. The de-molded, at least partially cured insert is then placed back on the UV light source for ˜40 seconds to ensure complete curing of the abrasive insert.

[0063] Useful abrasive particles may comprise, for example, fused aluminum oxide (including white fused alumina, heat-treated aluminum oxide, and brown aluminum oxide), ceramic aluminum oxide, heated treated aluminum oxide, silicon carbide, diamond (natural and synthetic), cubic boron nitride, boron carbide, titanium carbide, garnet, fused alumina-zirconia, ceramic alumina-zirconia, diamond, zirconia, and combinations thereof. Of these, diamonds are preferred. Useful diamonds may be either natural diamonds or man-made diamonds. The diamonds may include a surface coating (e.g., nickel or other metal) to improve the retention of the diamonds in the resin matrix.

[0064] Abrasive particles may also be present in abrasive agglomerates. Such agglomerates comprise a plurality of the abrasive particles, a matrix material, and optional additives. The matrix material may be organic and/or inorganic. The matrix material can be, for example, polymer resin, glass (e.g., vitreous-bond diamond aggregates), metal, glass-ceramic, ceramic (e.g., ceramic-bond agglomerates), or a combination thereof. For example, glass, such as silica glass, glass-ceramics, borosilicate glass, phenolic, epoxy, acrylic, and the other resins can be used as the agglomerate matrix material. Abrasive agglomerates may be randomly shaped or have a selected shape associated with them. The agglomerate particles are also fired.

[0065] Fired agglomerated particles are manufactured according to our US provisional application Ser. No. 62/427,811 filed Nov. 30, 2016 (See also U.S. Pat. No. 11,203,706) the entire contents of which are incorporated by reference herein.

[0066] The entire contents of my co-pending application U.S. Ser. No. 15/371,149 entitled “Composite Article For Maintaining And Cleaning Hard Surfaces” filed Dec. 6, 2016; is in its entirety herein incorporated by reference.

[0067] When float trowels constructed as above described are applied to the finish trowels on the machine, the machine may be operated in very much the conventional manner except that a knob is adjusted so that the finish trowels and consequently the float trowels thereon will assume perfectly horizontal positions which are required in performing the floating operation. As the float trowels have upwardly bent side edges, particularly the leading edge 32, there is no tendency of the float trowels to dig into the wet cement in performing the floating operation, Furthermore, as the float trowels have their pockets open rearwardly and are applied over the leading edge 47 of the finish trowels, there is very little danger or tendency for the float trowels to become displaced from the finish trowels. In many instances the retaining spring clip 37 may be unnecessary due to the fact that the drag on the float trowels in the course of their movement tends to push the float trowels onto the finish trowels.

[0068] When the floating operation is completed the spring clips 37 may be sprung upwardly to release the float trowels and they may be easily and quickly removed. This exposes the bottom surfaces of the finish trowels and the machine may then be used in the manner to perform the finishing operation in the usual manner.

[0069] All patents, patent applications and publications cited in this application including all cited references in those patents, applications and publications, are hereby incorporated by reference in their entirety for all purposes to the same extent as if each individual patent, patent application or publication were so individually denoted.

[0070] While the many embodiments of the invention have been disclosed above and include presently preferred embodiments, many other embodiments and variations are possible within the scope of the present disclosure and in the appended claims that follow. Accordingly, the details of the preferred embodiments and examples provided are not to be construed as limiting. It is to be understood that the terms used herein are merely descriptive rather than limiting and that various changes, numerous equivalents may be made without departing from the spirit or scope of the claimed invention.