Drum and Cutter Assembly for a Planing Machine

The present invention relates to machinery for planing flat surfaces comprised of, for example, concrete or asphalt. More particularly, the present invention relates to an improved drum and cutter assembly for such planing apparatus.

Planes utilized in connection with concrete or asphalt surfaces are generally known and are typically used during a resurfacing operation, removing paint and/or removing excess concrete/asphalt to provide a desired finished surface state. Such apparatus is generally comprised of an engine driven drum and cutter assembly located at the front of a wheeled carriage which is guided by an operator. The drum and cutter assembly is oriented transversely across the carriage and horizontal to the surface to be planed. The cutter subassembly which is mounted on the drum is comprised of sets of circular multi-toothed cutting elements and annular spacers which are mounted on a plurality of cutter shafts which rotate about the central axis through the assembly. The cutting elements and annular spacers are manually assembled piece by piece on each shaft in a predetermined configuration depending upon the task at hand or when repair is required. An inherent limitation exists inasmuch as it is a time consuming operation when the cutting elements and spacers must be individually placed on the respective shafts each time a change is required in the planing configuration. This is unnecessarily tedious and inefficient, particularly when working at a job site. A typical example of the known type of planing machine is shown and disclosed in U.S. Pat. No. 3,156,231, issued Nov. 10, 1964, which is, moreover, assigned to the assignee of this invention.

Accordingly, it is the primary object of the present invention to provide an improvement in apparatus for planing rough surfaces.

It is another object of the present invention to provide a new improved plane for resurfacing concrete and/or asphalt surfaces.

It is a further object of the present invention to provide an improved drum and cutter assembly for planing apparatus.

It is still another object of the invention to provide a means for facilitating the preassembly of a cutter subassembly mounted on a cutter drum of a planing machine.

The objects of the present invention are fulfilled by providing an elongated acrylic plastic tube which holds a set of multitoothed circular cutting elements and annular spacers which are arranged in a predetermined order on the tube to provide a desired planing cutting pattern spanning a predetermined dimension along a linear axis parallel to the surface to be planed. The cutting elements and spacers are assembled by hand in a jig which permits the elongated plastic tube to be oriented in a vertical position for receiving the cutting elements and annular spacers. The jig additionally permits the attachment of a retaining clip at each end of the tube for holding the assembled pieces together. Once assembled, the completed cutter subassembly is mounted on a cutter shaft of which there are a plurality of cutters and spacers arranged parallel to and offset from the central axis of the cutter drum which is rotatably driven by a motor. Upon rotation of the drum assembly, the acrylic tube of the cutter subassembly disintegrates, providing the required relative radial movement or play between the cutting elements and the cutter shaft.

The objects of the present invention and the attendant advantages thereof will become more readily apparent by reference to the following drawings wherein like numerals refer to like parts, and wherein:

FIG. 1 is a fragmentary perspective view generally illustrative of a planing machine;

FIGS. 2 and 3 are longitudinal central cross sections of known prior art drum and cutter assemblies used in connection with the apparatus shown in FIG. 1;

FIGS. 4 and 5 are top planar views generally illustrative of two types of cutter elements utilized in connection with the drum and cutter asemblies shown in FIGS. 2 and 3;

FIG. 5 is a perspective view of a six cutter shaft drum subassembly for the drum and cutter assembly shown in FIGS. 2 and 3;

FIG. 7 is an exploded perspective view of a simplier four cutter shaft drum subassembly;

FIGS. 8 and 9 are two illustrative diagrams of the manner in which a locking plate of the drum assembly shown in FIG. 7 operates to lock the cutter shafts in place on respective drum assemblies;

FIG. 10 is an exploded perspective view of the improved cutter subassembly comprising the preferred embodiment of the subject invention;

FIG. 11 is a central longitudinal cross sectional view of a preassembled cutter subassembly in accordance with the subject invention mounted on a cutter shaft; and

FIG. 12 is a longitudinal central cross sectional view of a jig used for assemblying the cutter subassembly shown in FIG. 9.

Referring now to the drawings and more particularly to FIG. 1, reference numeral 10 denotes what is commonly referred to as a plane utilized, for example, in resurfacing concrete/asphalt surfaces. The plane 10 includes, among other things, a carriage 12 which supports an engine 14 which is adapted to power and rotate a drum and cutter assembly 16 which spans the width of the carriage 12. The assembly 16 supports a plurality of cutter subassemblies 18 which are mounted on respective cutter shafts 20 between a pair of end plates 22 and 24. This is further shown in FIGS. 2 and 3 where there is disclosed two typical prior art drum and cutter assemblies.

Referring now to FIG. 2, a first example of a typical known prior art cutter and drum assembly comprises the assembly 16-1 and wherein a plurality of circular toothed cutting elements 26 are arranged in spaced relationship on respective cutter shafts 20 which are arranged around and offset from a central drive shaft 30 which is coupled to and driven by the motor 14 in FIG. 1. The cutter elements 26 are separated from each other by a plurality of like sized annular flat spacers 32. In order to provide support for the cutter shafts 20, a plurality of brace members 34 mounted on the drive shaft 30 extend radially outwardly therefrom to a respective cutter shaft 20 midway between the end plates 22 and 24. Further as shown in FIG. 2, the array of cutter elements 26 are mutually offset with respect to the cutting elements on the adjacent cutter shaft 20 in order to provide a resultant cylindrical cutting surface which is co-extensive across the span of the two end plates 22 and 24.

The configuration shown in FIG. 2, for example, would require 68 cutting elements and 426 spacers which would provide a medium finish planed surface. This might be described as a general purpose arrangement for the removal of excess concrete/asphalt or provides an ideal surface for bonding overlayment or epoxy coatings in a resurfacing operation. The cutting elements 26 comprise circular generally flat multitoothed elements such as shown in FIGS. 4 and 5. FIG. 4, for example, discloses a cutting element 26' having a plurality of radial cutting teeth 36 which have blunt outer end surfaces 38 while the cutting element 26" shown in FIG. 5 includes a plurality of radial cutting teeth 40 which terminate in a point 42 as shown.

A variation of the drum and cutter assembly shown in FIG. 2 is disclosed in FIG. 3. There a drum and cutter assembly 16-2 is shown comprising pairs of cutting elements 26 which are contiguously placed side by side on respective cutter shafts 20 while being spaced apart by a plurality of spacers 32 while being spaced apart by a plurality of spacers 32 between pairs of cutting elements. In order to compensate for the space taken up by the center braces 34, the innermost cutter elements comprise selectively placed sets of four cutter elements 26 arranged on one or both sides of a respective center brace 34. Such a configuration requires a total of 150 cutter elements and 292 spacers. In its operation it provides a fine broom like finish to the planed surface and is particularly useful for fast cutting of shallow depths as well as for traffic line and epoxy removal.

In accordance with prior art practice, all of the cutting elements 26 and spacers 32 are assembled piece by piece on the cutter shafts 20 of the drum and cutter assembly 16 as the job dictates.

Referring now to FIG. 6, this piecemeal assembly operation is carried out for the embodiment shown in FIGS. 2 and 3 by sliding each of the six cutter shafts 20 through equally spaced respective bore holes 46 and 48 in the end plates 22 and 24 respectively.

A simpler version of the drum assembly, without cutting elements and spacer elements assembled thereon, is shown in FIG. 7 and comprises an arrangement having only four cutter shafts 20 slidably linked between the end plates 22 and 24 having just two center braces 34 located midway between the end places 22 and 24. What is additionally disclosed in FIG. 7 is the means by which the cutter shafts 20 are locked in position between the end plates once loaded with an array of cutter elements 26 and spacers 32, not shown. This typically involves the use of an outer retaining plate member 50 secured, for example, by screws, not shown, to the outer surface of the right end plate 24 and an outer rotatable locking plate 52 located externally of the left hand end plate 22. The locking plate 52, moreover, includes a plurality of equally spaced slots 54 between a number of equally spaced bores 56 through which a respective cutter shaft 20 can pass therethrough when aligned with the bores 44 and 46 in the end plates 22 and 24. The rotatable locking plate 52 furthermore is shown in FIGS. 8 and 9 in an open and locked position respectively. Each of these positions is determined by tightening and loosening a set of bolts 58 which pass through the slots 54 and engage threaded holes 59 (FIG. 7) in the end plate 22. As shown in FIG. 8, in the open position, the bores 56 are aligned with the location of the four cutter shafts 20, while in FIG. 9, the locking plate 52 is shown rotated counter-clockwise so that the inner surface of the plate member 52 abuts the ends of the cutter shafts 20 so that they cannot be removed.

The present invention is directed to an improvement in the assembling and changing the pattern of cutting elements, on demand, as the specific task at hand dictates. The invention removes the piecemeal assembly of the cutting elements 26 and annular spacers 32 in favor of a preassembled arrangement of these components prior to their being installed on a drum assembly as shown in FIGS. 6 and 7.

Referring now to FIG. 10, reference numeral 60 denotes an elongated tube having a length dimension ranging between 4.0 and 6.0 inches and comprised of acrylic plastic upon which a plurality of cutting elements 26 and spacers 32 are placed in order to form a predetermined cutter configuration such as shown in FIGS. 2 and 3 while being held in place by a pair of circular metal clips 62 and 64 and having a serrated circular inner surface which fits over the outer diameter of the tube 60. The cutting elements and spacers include central circular bores of approximately 1.0 inches in diameter and accordingly the dimension of the outer diameter of the tube 60 is slightly less than 1.0 inch, being for example 0.960.+-.0.015 inches while having a wall thickness ranging between 0.05 and 0.06 inches. Typically the outer diameter of cutting elements is 3.0 inches or more while the outer diameter of the spacers is at least 1.5 inches. The components are assembled by hand into the desired cutting configuration, for example, as shown in FIG. 11 where they are then loaded onto a cutter shaft 20. What this accomplishes is a reduction in loading time on the planing machine. For example, the loading time required for a conventional drum and cutter assembly as shown in FIGS. 2 and 3 is thirty five to forty minutes; however, with a preassembled cutter subassembly on the acrylic plastic tube 60, loading of preassembled cutter subassemblies can be accomplished in about one minute.

In order to facilitate the manual assembly of the cutter elements 26 and spacer elements 32 on the acrylic plastic tube 60, a mounting jig 66 shown in FIG. 12 is provided. The jig is comprised of a body member 68 having a substantially flat bottom surface 70 for placement on a table or bench, not shown. Body member 68 additionally includes an upwardly projecting solid cylindrical portion 72 which extends above the upper surface 74 and having a diameter slightly less than the inner wall diameter of the tube 60 so that the tube can be slid downwardly thereover and be held in a vertical position. A circular recess 76 is formed at the base of the cylindrical portion 72 so that the lower extremity of the tube can extend into the recess when a downward movement is provided, for example, by an operator. The recess 76 has for its objective the placement of a retaining clip 62 (FIG. 10) on the end of the tube both at the beginning and end of an assembling operation prior to its loading onto a cutter shaft 20 as shown in FIG. 11.

As further shown in FIG. 12, a retaining clip is placed over the base portion 72 where it rests on the upper surface 74 with the recess 76 being situated beneath it. As the tube 60 is pushed down over the clip 62, the serrated inner edge thereof engages the outer wall surface of the tube 60. Thus when assembly is begun, one of the clips 62, for example, is placed on the jig 66 which is followed by forcing the tube 60 downwardly over the jig portion 72 which engages the clip. While in place, a set of cutter elements 26 and spacer elements 32 are manually stacked on the tube 60 in the desired combination. When all of the cutter and spacer elements are in place, the tube 60 is taken off the jig and the other spacer, for example 64, is placed on the jig and the other end of the tube 60 is forced down over the cylindrical jig portion 72 for securing the clip to the other end of the subassembly. Once this operation is completed, it can be stored or immediately mounted on the cutter shaft 20 of the paving machine, e.g. the machine 10 shown in FIG. 1.

In operation, while the acrylic plastic tube disintegrates as soon as the paving machine 10 on which the preassembled cutter subassembly begins to rotate. The tube 60 is effect pulverizes and in doing so provides a needed radial separation or "play" between the cutter elements 26 and spacer 32 and the cutter shaft 20 on which they are mounted. This play is needed for proper machine operation when the cutting elements come to bear on the surface being planed.

Thus what has been shown and described in an improvement in planing machines which permits the assembly of preassembled cutter subassemblies on a drum in a fraction of the time heretofore required. This is coupled with the additional feature that the plastic tube upon which the cutter elements are mounted disintegrates just as soon as it is put into operation providing the needed clearance between the cutting elements and the cutting shaft on which it is mounted.

It should be further understood that many other variations of the invention described herein may be made as would occur to one of ordinary skill in the art without department from the general spirit and scope of the present invention.