Circular saw blade for cutting grooves in concrete

Abstract: An improved circular saw blade assembly for cutting in a single pass a two tier groove in a concrete areaway. The saw blade body (11) having a first row of cutting elements (12) in the form of a metallic matrices containing fragmented diamond particles secured to the blade body periphery. A plurality of cutting blocks (15) formed of the same material as the cutting elements are positioned in a circular configuration intermediate the periphery (16) and the center (17) of the blade body. The cutting blocks (15) are secured to the blade body (11) so as to position the cutting faces on the cutting blocks (15) on each side of the blade whereby the cutting faces coact to cut a groove in the concrete above and wider than the groove cut by the peripheral cutting elements (12).

Description: BACKGROUND OF THE INVENTION The present invention relates to circular saw blades used to cut expansion grooves in concrete areaways or the like. The cut grooves are then filled with a compression sealant of neoprene or other similar synthetic rubberlike material which allows the grooves to function as expansion joints in response to temperature induced expansion or contraction. The current state of the art of expansion joints indicates a preference for a two tier joint that is commonly made in two cutting steps. The first step involves the cutting of a narrow groove to a predetermined depth. This is followed by the cutting of a second wider groove cut to a lesser depth above the narrow groove. This wider and shallower groove receives the compression seal material. The two cutting step approach has an obvious disadvantage in that after the first cut is made the blade must be changed to a smaller diameter and wider blade before the second cut can be made. An example of this approach is shown in U.S.-A-4,456,303. U.S.-A-3,127,887 discloses a saw blade assembly capable of opening out an existing groove in a single pass of the blade over the concrete. The saw blade assembly disclosed comprises a composite blade body including a pair of outside cutting disks and a central inside spacer and routing disk. The central spacer and routing disk is of the same diameter as the diameter of the outer cutting disks. This three blade construction is a complicated and expensive blade assembly and cannot cut a two tier groove. GB-A-2061817 discloses a circular saw assembly for sawing through board material. The saw has cutters mounted circumferentially and radially inward of the periphery, the cutters extending on both sides of the saw blade and bevelling one of the sawn edges of each sawn piece in use. SU-A-259124 discloses a "Road Surface Cutter" for making seams in the hardened surfaces of roads, airfields, etc. that produces a two tier seam in one cut. The disclosed cutter comprises a circular blade body or core having a thick, metal, center disk portion and a thin rim surrounding the center disk portion. The perimeter of the rim and each side of the disk portion carries rings of cutting material, the rings being made of metallic matrix with abrasive matter such as diamond fragments embedded therein. There appears to be little provision for protecting the core against premature wear in critical areas caused by abrasive particle buildup during the sawing operation. It is an object of the present invention to provide a saw blade of relatively simple construction that would enable a two tier expansion joint to be cut efficiently in a single pass over a paved areaway. More particularly it is an object of the present invention to provide a saw blade in which the saw blade assembly includes a single circular blade body or core of uniform thickness having a plurality of spaced cutting elements secured to the periphery of the blade body and also having a plurality of spaced cutting blocks arranged in a circular configuration on the blade body intermediate the periphery and the blade center whereby a two tier expansion groove is automatically cut in a single pass over the paved area. It is a further object of the present invention to provide a saw blade that has provision for the flow of coolant over and around the cutting elements and cutting blocks thereby to increase the cutting life of the blades and to allow the cutting speed of the blade to be increased. These and other objects of the invention will be apparent from the following disclosure of preferred embodiments thereof. BRIEF SUMMARY OF THE INVENTION According to the invention there is provided a circular saw blade assembly for cutting in a single pass a two tier groove in a paved areaway, the saw blade assembly including a circular blade body having a peripheral cutting element secured to the periphery of the blade body, and a side cutting element providing a cutting face to the side of the blade body, the peripheral and side cutting elements being radially spaced to facilitate cutting of a two tier groove and being in the form of metallic matrices containing fragmented diamond particles, characterized in that the blade body is of substantially uniform thickness, a plurality of cutting elements are provided at the periphery of the blade body and a plurality of cutting blocks at the side thereof, the blade body being provided intermediate its periphery and its center with a plurality of arcuately spaced cutting block positioning means arranged in a circular configuration concentrically of the periphery of the blade body, and retention means securing the cutting blocks to the blade body at the positioning means with cutting faces on opposite sides of the blade body. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a fragmentary side elevational view of a saw blade assembly constructed according to the principles of the present invention; Figure 2 is a sectional view taken on the line 2-2 of Figure 1; Figure 3 is a sectional view taken on the line 3-3 of Figure 1; Figure 4 is an enlarged fragmentary elevational view of a modified portion of Figure 1; Figure 5 is an enlarged fragmentary elevational view of a further modified portion of Figure 1; Figure 6 is an elevational view of component of the structure shown in Figure 5; Figure 7 is a fragmentary view of a saw blade assembly in part similar to Figure 1 showing a further embodiment of the invention; Figure 8 is a sectional view taken on the line 8-8 of Figure 7; Figure 9 is a fragmentary side elevation view in part similar to Figure 1 showing a further modification of the saw blade assembly. Figure 10 is a sectional view taken on the line 10 of Figure 9; Figure 11 is a view taken looking in the direction of the arrow 11 in Figure 10; Figure 12 is a view similar to the view in Figure 11 showing a further embodiment of the invention; Figure 13 is a fragmentary side elevational view in part similar to Figure 9 showing a further modification of the saw blade assembly closely related to the Figure 12 embodiment; Figures 14 and 15 are side elevational views of modified versions of the components shown in Figures 11 and 12, respectively; Figure 16 is a fragmentary side elevational view in part similar to Figure 1 showing a further embodiment; Figure 17 is a sectional view taken on the line 17-17 of Figure 16; and Figure 18 is a view taken in the direction of the arrow 18 in Figure 17. DETAILED DESCRIPTION OF THE INVENTION Referring first to Figures 1 to 3, the saw blade assembly generally designated 10, only a fragmentary portion of which is shown, comprises a single, metal, circular blade body 11 of uniform thickness having a plurality of peripherally mounted cutting elements 12. The cutting elements 12 are in the form of metallic matrices containing fragmented diamond particles. The cutting elements 13 are separated by gaps 13 that communicate with slots 14 in the blade body 11. The slots 14 function to increase the turbulence and therefore the cooling effect of the coolant applied to the rotating blade during the sawing operation. The flow of the coolant also causes the abrasive particles of concrete to be washed away therefore decreasing the wear on the core. The foregoing features as broadly described are well known in the concrete saw blade art as noted in L.H. Metzger U.S. patent 3,127,897. In accordance with the present invention a second set of cutting elements, hereinafter referred to as cutting blocks 15, are mounted on the blade body intermediate its periphery 16 and the blade body 17 center. Each cutting block 15 consists of a metal support plate 18 to which is bonded a metallic matrix 19 containing fragmentary diamond particles. The blade body 11 has a plurality of spaced cutting block positioning means arranged in a circular configuration concentrically of the blade body periphery. At best seen in Figure 2, the positioning means comprises a set of three tapped holes 21 adapted to receive fastening devices in the form of screws 22 for securing the cutting block support plates 18 and thereby the matrices 19 to the blade body 11. The cutting blocks 15 are mounted in aligned pairs on opposite sides of the blade body 11. The blade body 11 is provided with a pair of parallel, elongated, radially extending slots 23 partially underlying each aligned pair of blocks 15. The slots 23 permit coolant to flow around the blocks 15 during the sawing operation. In operation the saw blade assembly 10 is able to cut a two tier expansion joint in a concrete or other paved areaway. The portion of the saw blade 10 between the cutting elements 12 and the cutting blocks 15 cuts a groove having the width of the cutting elements 12. The cutting faces 20 on the aligned pairs of cutting blocks 15 coact to cut a groove above and wider than the groove being cut by the cutting elements 12. For example, the specification for an airport concrete runway may require a 14 inch thick layer of concrete. The groove to be cut by the peripheral cutting elements is required to be 1/8 of an inch wide and 3 1/2 inches deep from the surface. The second groove to receive the neoprene or synthetic rubber compression seal is required to be 1/2 inch wide and the depth to be substantially less than that of the groove cut by the cutting elements. The depth of the second groove may vary depending on requirements established by the compression seal manufacturer. The saw blade assembly can be manufactured to accommodate any desired depth for the compression seal. The set of screw holes 21 can be radially located to position the cutting blocks closer to or further away from the blade periphery to meet the compression seal depths requirements. The advantage derived from the two tier expansion joint with the increased depth of the narrow groove is that any crack that may developed in the concrete will occur below the lower end of the narrow groove thus preserving the integrity of the compression seal portion of the expansion groove. Depending on the nature of the aggregate used in the concrete, it has been found that critical areas of the blade body adjacent the cutting faces of the cutting blocks will show premature wear. Figure 4 and Figures 5 and 6 show two ways of minimizing this wear by utilizing wear resistant elements. In Figure 4, a single enlarged width slot 24 has been shown in place of the slots 23 shown in Figure 1. The slots 24 are fitted with strips 25 of tungsten carbide having a hardness of approximately Rockwell C65 or diamond impregnated material. The wear strips 25 are effective to break up any aggregate particles that would cause wear on the blade body surfaces adjacent the cutting blocks 15. In Figure 5, the slots 24 are filled with a wear resistant insert having a metallic matrix portion 27 containing fragmented diamond particles. As shown in Figure 6, the matrix portion 27 is attached to a tab portion 28 having a screw hole 29 adapted to receive the central screw 22 of the screws holding the cutting blocks 15 in place on the blade body 11. The wear resistant inserts 27 being in position to break up any aggregate dragging under the cutting blocks 15, are able to minimize wear on critical areas of the blade body adjacent the cutting blocks 15. In the form of the invention shown in Figures 7 and 8, the saw blade assembly, generally designated as 30, has the same peripheral cutting elements as Figure 1 embodiment. That is, the saw blade assembly has a plurality of peripherally mounted cutting elements 12 separated by gaps 13 that communicate with coolant distributing slots 14. In this form of the invention, the blade body, herein designated 31, has a plurality of circularly spaced circular ring sector openings 32. Each opening contains a cutting block 33 a metallic matrix containing fragmented diamond particles; the matrix being in the shape of a slab. Each cutting block 33 has a length less the circular width of the opening 32, a thickness less than the distance between the inner radial edge 34 and the outer radial edge 35 of the opening and a width greater than the thickness of the blade body 31. The width of the cutting block 33 in relation to the thickness of the blade body 32 is best seen in Figure 8. Lengthwise the slab forming the cutting block 33 has a slight curvature complementary to the curvature of the inner radial edge 34 of the opening 32. The cutting blocks 33 are retained in the openings by being bonded or otherwise secured, as by silver solder, to the inner radial edge 34 of the opening 32. As shown in Figure 8, each cutting block extends later-ally of the blade 31 thereby providing cutting faces on both sides of the blade effective to cut a second tier groove of the desired width. The clearance of the openings 32 on all sides of the cutting blocks 33, except the bonded side, is great enough to allow coolant to flow around each cutting block during the sawing operation. Referring now to Figures 9 to 12, inclusive, a further embodiment of the invention comprises a saw blade assembly, herein designated 40 having cutting elements 12 located on the periphery of the blade body 41. In this embodiment the blade 41 is provided with an inner circle of substantially rectangular openings 42 with its inner edge 43 and outer edge 44 being curved to be concentric with the periphery of the blade body. Each cutting block 45 is formed of two elongated matrix pieces 46 and 47, each impregnated with diamond cutting fragments. The matrix piece 46 is of substantially square cross section and the matrix piece 47 is of substantially L-shaped cross sections, as best as seen in Figure 10. The longitudinal length of each matrix piece is substantially equal to the circumferential length of a rectangular opening 42. The vertical height of the L-shaped cross section of the matrix piece 47 is substantially equal to the distance between the inner edge 43 and the outer edge 44 of the openings. Support members 48 are bonded or otherwise secured to the base edge 49 of the square cross section matrix piece and to the base edge 50 of the L-shaped matrix piece 47. Fastener devices, such as screws 51 secure each of the matrix piece support members 48 to the blade body 11 and to each other adjacent the inner edge 43 of the rectangular openings 442. the secured matrix pieces form a cutting block 45 of substantially T-shape having cutting portions extending equidistantly through the rectangular opening to both sides of the blade body 11. As with the previously described embodiments, the cutting block 45 is able to cut an upper tier groove to the desired width to receive a compression seal. Referring now to the further embodiment of the invention shown in Figures 13 to 15, the saw blade assembly herein designated 60 is closely related to the previously described embodiment of Figures 9 to 12, inclusive, The major difference is that the rectangular openings 53 and the cutting blocks 54 are canted or angularly inclined from the squared positions of the rectangular openings 42 and cutting blocks 45 shown and described with respect to Figures 9 to 12. Figure 14, for example, shows a matrix piece 55 mounted on a support member 56 that corresponds to the matrix piece 47 and support member 48 of Figure 11, except for the angular tilt. Figure 15 shows a matrix piece 57 supported on support member 56 that corresponds to the matrix piece 46 mounted on the support member 48, except for canted or inclined relationship. Cooling water applied to the blade body will flow past the cutting blocks to cool the same. The slanted or inclined sides of the cutting blocks 54 will assist the flow water past the cutting blocks and help sweep cutting debris away from the cutting blocks. In Figures 16 to 18, inclusive, still another form of the invention has been shown. The saw blade assembly, herein designated 60 has the same peripheral cutting elements 12 as the previously described embodiments. In this embodiment the blade body 61 has an inner ring of circularly spaced circular openings 62. Each cutting block 63 has a cylindrical body portion 64 which fits into a circular opening 62. The body portion 64 has laterally extending side portions 65 - 66 extending equidistantly from both sides of the blade body 61. The side portions are truncated at 67 to form the cutting edges of the cutting blocks 63. The blade body is reinforced inwardly of the cutting blocks 63 by reinforcing rings 68. The cutting blocks portion 66 have an inwardly extending appendage 69 that overlies the ring 68 on that side of the blade body 61. A fastener device 70, shown as a screw, extends through the cutting block appendage 69 into the rings 68 and the blade body 61 to secure the cutting block 63 in place on the blade body 61. The rings 68 are slotted at 71 to assist in coolant flow around the cutting blocks during the sawing operations. While the invention has been illustrated with respect to several specific embodiments thereof, these embodiments should be considered as illustrative rather than limiting. Various modifications and additions may be made and will be apparent those skilled in the art. Accordingly, the invention should not be limited by the foregoing description, but rather should be defined only by the following claims.

Claims: A circular saw blade assembly (10) for cutting in a single pass a two tier groove in a paved areaway, the saw blade assembly (10) including a circular blade body (11) having a peripheral cutting element (12) secured to the periphery of the blade body (11), and a side cutting element (19) providing a cutting face to the side of the blade body (11), the peripheral and side cutting elements being radially spaced to facilitate cutting of a two tier groove and being in the form of metallic matrices containing fragmented diamond particles, characterized in that the blade body is of substantially uniform thickness, a plurality of cutting elements (12) are provided at the periphery of the blade body (11) and a plurality of cutting blocks (19) at the side thereof, the blade body (11) being provided intermediate its periphery and its center with a plurality of arcuately spaced cutting block positioning means (23) arranged in a circular configuration concentrically of the periphery of the blade body (11), and retention means (22) securing the cutting blocks (19) to the blade body (11) at the positioning means (23) with cutting faces on opposite sides of the blade body (11). The blade assembly of claim 1, in which the positioning means (23) comprises a plurality of spaced sets of first fastener receiving holes (23) in the blade body (11), and the cutting blocks (19) are bonded to respective support plates (18) each provided with a set of second fastener receiving holes (21), and the retention means (22) comprises fastener devices (22) received in the first and second fastener receiving holes to hold the cutting blocks on opposite sides of the blade body (11) in paired alignment. The blade assembly of claim 1 or claim 2, in which the blade body (11) is provided with elongated radially extending slots (23) partially underlying the cutting blocks, the slots permitting coolant to flow around the cutting blocks during the sawing operation. The blade assembly of claim 3 in which said radially extending slots (23) are said first fastener receiving holes (23). The blade assembly of claim 3 or claim 4, in which wear resistant insert means (25) are fitted in said slots (23) to minimize the wear on adjacent faces of the blade body (11). The blade assembly of claim 1, in which the positioning means (23) comprise a plurality of circularly spaced ring sector openings (32), the cutting blocks (33) being arcuately slab-shaped, and each cutting block (33) being mounted on the radially inner most surface of a respective ring sector opening (32). The blade assembly of claim 6, in which the retention means is a bonding medium for attaching one surface of each cutting block to the sector opening (32), and the sector openings (32) are larger than the cutting blocks (33) to provide clearance on all sides except the side bonded to the block (33) thereby to permit coolant to flow around the cutting block during the sawing operation. The blade assembly of claim 6 or claim 7, in which each cutting block (33) extends laterally of the blade body (11) on both sides thereby to provide the cutting faces. The blade assembly of claim 1, in which the positioning means (23) comprises a plurality of circularly spaced substantially rectangular openings (42) in the blade body (11) ; each cutting block (45) consists of a square segment (46) and an L-shaped segment (47), the base of the L-shaped segment (47) being equal in width to the width of the square segment (46) plus the thickness of the blade body whereby the cutting faces of both segments will extend equidistantly from opposite sides of the blade body; support members (48) being bonded to the base of each segment (46,47) and the retention means comprises fastener devices (51) extending through the support members (48) and blade body (11). The blade assembly of claim 9, in which the length of each segment (46,47) is substantially equal to the circumferential length of a respective rectangular opening (42) and the height of the L shaped segment (47) is substantially equal to the radial distance between the inner and outer edges of the rectangular opening (42). The circular saw blade assembly of claim 9 or claim 10, in which the rectangular openings (42) are larger than the cutting blocks to provide clearance on all sides except the supported base side for coolant to flow around the cutting block during the sawing operation. The blade assembly of claim 1, in which the positioning means (23) comprises a plurality of circularly spaced circular apertures (62) in the blade body (11); each cutting block (63) having a substantially cylindrical body portion (64) adapted to fit into a respective circular aperture (62) with laterally extending portions (65,66) extending equidistantly from both sides of the blade body (11); one of the laterally extending portions (65,66) having a radially inwardly extending appendage (69), the blade body (11) on both sides having reinforcing rings (68), one of which is interposed between the blade body (11) and the depending appendage (69); and the retention means securing the cutting block (63) to the blade body (11) comprises a fastener device (70) securing the appendage (69) to the rings (68) and the blade body (11) therebetween. The circular saw blade assembly of claim 12, in which the rings (68) are slotted to assist coolant flow around the cutting blocks (63) during the sawing operation.

Inventors: YOUNGER RICK, YOUNGER, RICK
Applicants: YOUNGER RICK, YOUNGER, RICK
Application year: 1990
Main classification: B28D1
IPC codes: B28D1, B23D61, E01C23