Patent Application
20180200857
The disclosure relates generally to a pad assembly and more particularly to a floor grinding pad apparatus.
It is known to use fibrous pads for polishing and grinding floors within industrial or commercial buildings. Such polishing or grinding pads are ideally suited for use on concrete, terrazzo, and natural (e.g., marble), engineered and composite stone floors. Examples of such pads and the powered machines used to rotate such can be found in the following U.S. patents and patent publication numbers: 2011/0300784 entitled “Flexible and Interchangeable Multi-Head Floor Polishing Disk Assemby” which was invented by Tchakarov et al. and published on Dec. 8, 2011; U.S. Pat. No. 9,174,326 entitled “Arrangement For Floor Grinding” which issued to Ahonen on Nov. 3, 2015; U.S. Pat. No. 6,234,886 entitled “Multiple Abrasive Assembly and Method” which issued to Rivard et al. on May 22, 2001; U.S. Pat. No. 5,605,493 entitled “Stone Polishing Apparatus and Method” which issued to Donatelli et al. on Feb. 25, 1997; and U.S. Pat. No. 5,054,245 entitled “Combination of Cleaning Pads, Cleaning Pad Mounting Members and a Base Member for a Rotary Cleaning Machine” which issued to Coty on Oct. 8, 1991. All of these patents and the patent publication are incorporated by reference herein.
Notwithstanding, improved floor grinding performance is desired. Furthermore, some of these prior constructions exhibit uneven wear in use which prematurely destroy the pads or cause inconsistent polishing or grinding. Moreover, floor unevenness and cracks may create only partial contact with abrasive grinding members, thereby adding extra grinding time and causing uneven grinding with some prior rigid devices.
In accordance with the present invention, a workpiece abrading pad apparatus is provided. In one aspect, a grinding pad apparatus employs a flexible pad, a flexible metallic reinforcement layer or ring, and multiple floor-grinding disks. In another aspect, a metallic reinforcement ring includes a central hole through which a fiber or foam pad is accessible. Another aspect employs a spring steel reinforcement ring to which multiple diamond-based abrasive disks or dots are attached. In yet another aspect, at least one floor-contacting disk attached to a reinforcement ring includes sintered powdered metal with diamond particles mixed therein. A further aspect employs abrasive, floor-contacting disks or dots including posts or mechanical fasteners extending from backsides thereof for attachment to a reinforcing ring or layer. A method of making a grinding pad apparatus is also presented.
The present pad assembly is advantageous over traditional devices. For example, the flexible metallic reinforcement layer or ring of the present pad apparatus advantageously allows greater and more even floor contact over worn areas and cracks due to disk-to-disk flexibility, which is expected to improve grinding performance. Furthermore, the disk post and method of manufacturing the apparatus advantageously provide a more secure attachment of components. The flexible metallic reinforcement ring, in combination with sintered powdered metal and diamond disks, provide enhanced durability during the grinding operation which is a much harsher, jarring and vibration-prone operating condition than for polishing or honing. Additional advantages and features of the present invention will be readily understood from the following description, claims and appended drawings.
A preferred embodiment of a grinding pad apparatus 21 is shown in
A reinforcement ring or layer 31 is secured to a bottom face or surface 32 of base pad 25, by a contact cement type of adhesive. Reinforcement ring 31 is generally annular having a central opening 33 with an inner diameter of approximately 9.5 inches and an outer diameter of approximately 14 inches for one version of the pad apparatus. Reinforcement ring 31 has a thickness greater than zero and up to 0.0304 inch (1 mm), and more preferably 0.0197 inch (0.5 mm). Reinforcement ring or layer 31 is metallic and more preferably a high carbon 1095, hardened and tempered spring steel material. Reinforcement ring 31 reinforces and adds some radial stiffness and toughness to the outer portion of pad 25 to resist rotational centrifugal forces when grinding, however, ring 31 advantageously allows a significant amount of torsional and longitudinal flexibility and resilience to pad apparatus 21 so it can flex with and follow any floor imperfections thereby producing uniform disk-to-disk floor contact for grinding. This is especially beneficial when worn areas of the floor or cracks in the floor are otherwise encountered by only some disks but not others. Without the present flexible ring, conventional more rigid pad assemblies may not remove enough floor material during the very abrasive grinding operation, which is not as important for the finer grit polishing or honing operations, by way of comparison.
A circular internal edge 33 of reinforcement ring 31 defines a central opening or hole 35 which exposes a central surface 37 of base pad 25. This large diameter internal edge 33 allows for easier torsional flexure of the ring during use. Base pad 25 and ring 31 preferably have concentrically aligned circular peripheral surfaces 39 and 41, respectively.
A plurality of abrasive tools such as floor-contacting disks or dots 51 are secured to a bottom surface 52 of reinforcement ring 31. In the example shown, disks 51 are made of a sintered powdered metal composition of bronze, copper and iron, to which is added diamond particles. The diamond particles are very course for grinding, preferably having a grit size of 100 or less, and more preferably 24-50. Each disk includes a generally circular body 54 with an exemplary outer peripheral diameter of 2.123 inches (54 mm), a total height below reinforcement ring 31 of 0.00787 inch (5.0 mm) and a depth of groove 53 of 0.0131 inch (3.0 mm).
An optional and cylindrically shaped post 55 projects from a backside of each disk body 54 in a longitudinal direction substantially parallel to a rotational axis of the pad apparatus, and is intergrally formed therewith as a single piece. Post 55 is approximately 0.394 inch (10.0 mm) wide and approximately 0.0591 inch (1.5 mm) long. Furthermore, post 55 projects through an aperture 57 pierced in ring 31. Multiple of the apertures are equally spaced apart in the ring. A distal end of post 55 is deformed to outwardly expand like a mushroom head thereby creating an enlarged head 59 which is laterally larger than aperture 57. Thus, ring 31 is sandwiched and compressed between head 59 and the backside of each disk 51 to mechanically attach and secure disks 51 to ring 31. Adhesive may additionally or instead be employed to attach and secure disks 51 to ring 31 with or without the posts, depending on the specific durability requirement and coarseness of the grit for grinding.
It is alternately envisioned that multiple parallel and spaced apart posts may project from each disk for insertion onto aligned apertures of the reinforcement ring. Moreover, it is alternately envisioned that one or more posts can have a generally polygonal shape, a flat side surface or a greater width in one lateral direction than another (e.g., a rectangle or oval). These alternate post configurations deter rotation of the disks relative to the attached reinforcement ring and base pad during grinding. In the example shown, six such disks 51 are secured about the circumference of reinforcement ring 51 in an equally spaced apart manner. The posts may be solid or at least partially hollow. Different sizes, a different quantity, and/or differently grooved disks may alternately be used. Furthermore, the ring apertures 57 are preferably circular but may alternately have one or more flat edges, or even be elongated slots in the inner or outer edges 33 and 41, respectively, of ring 31.
Grinding pad apparatus 21 is manufactured as illustrated in
While various embodiments have been disclosed, it should be appreciated that additional variations of the pad assembly are also envisioned. For example, while preferred dimensions and metallic materials have been disclosed hereinabove, it should alternately be appreciated that other dimensions and metallic materials may be employed. Moreover, circular peripheral shapes for the pad, reinforcement ring and disks are preferred, however, other arcuate or even generally polygonal peripheral shapes may be used although certain of the present advantages may not be fully realized. Alternate base pads 25 may be used, such as foam-rubber, felt or other such flexible materials. It is also noteworthy that any of the preceding features may be interchanged and intermixed with any of the others. Furthermore, it is alternately feasible to have a differently shaped inner edge or even no central hole in the reinforcement ring or layer, although the torsional flexure may be inadequate for some uses, and there may be undesired extra material costs and weight with such. Accordingly, any and/or all of the dependent claims may depend from all of their preceding claims and may be combined together in any combination. Variations are not to be regarded as a departure from the present disclosure, and all such modifications are entitled to be included within the scope and sprit of the present invention.
