Abstract:
The present invention is a tire cutting machine comprising of a base, a body member, a drive assembly means and a cutting assembly means. The drive assembly means includes a drive power means simultaneously engaged to a pair of front drive wheels and to a pair of rear drive wheels to provide rotation thereof. The front drive wheels are coaxially mounted in close relation to one another on a front drive wheel shaft extending between a first drive assembly arm and a second drive assembly arm. The rear drive wheels are coaxially mounted in close relation to one another and to a guide wheel which is directly engaged to the drive power means. The cutting assembly means includes a cutting power means simultaneously engaged to a front cutting wheel and to a rear cutting wheel to provide rotation thereof. The cutting assembly means is mounted such that the lower arc of the front cutting wheel passes between the upper arcs of the front drive wheels to form a front cutting assembly and, similarly, the lower arc of the rear cutting wheel passes between the upper arcs of the rear drive wheels to form a rear cutting assembly. In operation, a scrap tire, or a portion thereof, is passed between a cutting wheel and the corresponding drive wheels thereby cutting the tire. The front cutting assembly may be used to provide transverse cuts across the tire material or the tire material may be manipulated to provide decorative cuts or various shaped portions for practical or aesthetic uses. The rear cutting assembly is used primarily to cut strips of tire material, primarily of the tread portion of a scrap tire, and includes an adjustable guide to control the width of such strips.

Description:
CROSS REFERENCE TO RELATED DOCUMENTS 
     None 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO A MICROFICHE APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     One of the most pressing and difficult environmental issues of today is the disposal of scrap rubber tires, particularly those designed for highway use on trucks and automobiles. Such tires are typically manufactured to resist road hazards and last for tens of thousands of miles. It is this propensity to longevity, however, which makes the disposal of scrap tires extremely difficult. This problem is further complicated by the overall volume of scrap tires being discarded, running into the hundreds of thousands each year. 
     Various attempts to dispose of scrap tires have thus far met with only limited success. Stockpiling and landfills require significant acreage and provide ideal breeding grounds and habitat for mosquitoes, snakes and other undesirable vermin. Incineration of scrap tires releases various toxic substances into the atmosphere and recycling is generally a complex process requiring significant amounts of energy and has thus far proven to be cost prohibitive. Thus, there is a need for viable alternatives for the ultimate disposal of scrap tires and therefore a corresponding need for a tire cutting machine to facilitate such alternatives. 
     It has heretofore been the object of the several types of tire cutting machines disclosed in the prior art to cut scrap tires into various portions thereby reducing the overall volume required for storage of the scrap tires and facilitating the handling and ultimate disposal thereof. One of the types of tire cutting machines disclosed in the prior art generally cuts, shreds or rips the scrap tires into smaller random segments. Typical of such machines are those described in U.S. Pat. No. 4,576,339 issued Mar. 18, 1986, U.S. Pat. No. 4,613,087 issued Sep. 23, 1986, and U.S. Pat. No. 5,285,707 issued Feb. 15, 1994. Another type of tire cutting machines disclosed in the prior art generally cuts the scrap tires radially resulting in transverse segments thereof. Examples of this type of machine are described in U.S. Pat. Nos. 4,338,839 and 4,338,840 both issued Jul. 13, 1982, U.S. Pat. No. 5,133,236 issued Jul. 28, 1992, U.S. Pat. No. 5,331,146 issued Jul. 2, 1996, and U.S. Pat. No. 5,551,325 issued Sep. 3, 1996. It is a disadvantage of each of these machines, however, that no further operations may be performed on the resulting segments of the scrap tire and therefore, there are only limited options for the ultimate disposal thereof. 
     A third type of tire cutting machine, considered to be the most relevant prior art to the present invention, generally separates the sidewall portions of a scrap tire from the tread portion by using some combination of a driving means by which to move the scrap tire into a cutting means. These type machines, however, are generally limited to performing one cut, or set of cuts, depending upon the number of cutting means, per tire. For example, the machine disclosed in U.S. Pat. No. 5,235,888 issued Aug. 17, 1993, uses two separate cutting means to simultaneously separate the sidewall portions from the tread portion of a scrap tire. Once the sidewall portions are removed from a particular scrap tire, however, no further operations may be performed with this machine and there are therefore only limited options for ultimate disposal of the resulting portions of the scrap tires. Likewise, the machine disclosed in U.S. Pat. No. 4,072,072 issued Feb. 7, 1978, uses one or more cutting means such that each scrap tire is cut axially around the tread portion thereby resulting in separated sidewall segments and, depending upon the number of separate cutting means utilized, one or more tread segments. Again, however, once a scrap tire has been passed through this machine, the resulting segments have only limited options for ultimate disposal. 
     Similarly, the machines disclosed in U.S. Pat. No. 3,701,296 issued Oct. 31, 1972, and in U.S. Pat. No. 5,601,004 issued Feb. 11, 1997, both utilize a pair of cutting means to separate the tread portion of a scrap tire from the sidewall portions. These machines each contain a further means to transversely cut the severed tread portions such that said tread portions may be further utilized for some secondary purpose or stacked in a flat position. It is a disadvantage of the machine of U.S. Pat. No. 3,701,296, however, in that it requires the operator to manually force the severed tread portion along a cantilevered support member to engage the transverse cutting means thereby placing the operator at risk of serious personal injury. Likewise, it is a disadvantage of the machine of U.S. Pat. No. 5,601,004 in that it utilizes a hydraulic ram and a cutting blade to shear the severed tread portion transversely, requiring significant energy and strength of machine. It is a further disadvantage of these machines that, once the tread portion is severed, it may only be cut transversely into shorter segments thereby limiting the options for which the said tread portion may be used. 
     Thus, there is a need for a portable, safe and versatile machine with means of cutting scrap tires into multiple segments with control over both size and shape to provide alternative options for the ultimate use and disposal of scrap tires. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a machine for cutting scrap tires into numerous segments with a variety of shapes and sizes. The machine involves a base, a body member, a drive means assembly and a cutting means assembly, said cutting means assembly being vertically disposed above said drive means assembly. The drive means assembly includes a pair of front drive wheels, said front drive wheels being mounted on a front drive wheel shaft extending between a first drive assembly arm and a second drive assembly arm, and a pair of rear drive wheels. A drive power means is also included for providing rotation of the front drive wheels and the rear drive wheels. The cutting means assembly includes a front cutting wheel, said front cutting wheel being mounted on a front cutting wheel shaft extending between a first cutting assembly arm and a second cutting assembly arm, and a rear cutting wheel. A cutting power means is also included for providing rotation of the front cutting wheel and the rear cutting wheel. The cutting means assembly is positioned such that the lower arc of the front cutting wheel passes between the upper arcs of the front drive wheels to form a front cutting assembly and, similarly, the lower arc of the rear cutting wheel passes between the upper arcs fo the rear cutting wheels to form a rear cutting assembly. 
     In operation, a scrap tire, or a portion thereof, is passed between a cutting wheel and the corresponding drive wheels thereby cutting the tire. The front cutting assembly may be used to provide transverse cuts across the tire material or the tire material maybe manipulated to provide decorative cuts or various shaped portions for practical or aesthetic uses. The rear cutting assembly is used primarily to cut strips of tire material, primarily of the tread portion of a scrap tire, and includes an adjustable guide to control the width of such strips. Thus, it is an advantage of the present invention that material from a single scrap tire may be cut into a variety of shapes and thereby maximizing the use of the scrap tire material. Other features and advantages of the present invention are provided in the detailed description of the invention below. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a first side perspective view of the tire cutting machine of the present invention. 
     FIG. 2 is a first side perspective view of the tire cutting machine showing the drive mechanism for the front cutting area. 
     FIG. 3 is a second side perspective view of the tire cutting machine showing the rear cutting area. 
     FIG. 4 is a side view of the first side of the tire cutting machine. 
     FIG. 5 is a side view of the second side of the tire cutting machine. 
     FIG. 6 is a l front view of the tire cutting machine. 
     FIG. 7 is a top view of the tire cutting machine. 
     FIG. 8 is a sectional view of the front cutting assembly. 
     FIG. 9 is a sectional view of the rear cutting assembly. 
     FIG. 10 is a detail side view of the rear portion of the first drive arm and the first cutting arm. 
     FIG. 11 is a sectional view of the drive chain tension means. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, the tire cutting machine of the present invention includes a base member  1  and an upwardly extending body member  2 . Attached to and supported by said body member  2  is drive means assembly  50  having a first side and an opposite second side. Vertically disposed above drive means assembly  50  is cutting means assembly  10  having a first side and an opposite second side. Vertically disposed above cutting means assembly  10  is control box  110  with main on/off switch  111 , said control box  110  being connected to foot switch  113  by control lead  112 . 
     As detailed most clearly in FIG.  2  and FIG. 3 showing, respectively, a first and second perspective view of the tire cutting machine, drive means assembly  50  generally includes drive motor  51 , drive gear reduction means  58  having a first side and an opposite second side, a first drive assembly arm  62  and a second drive assembly arm  63 , a pair of rear drive wheels  64  and  64 ′ and a pair of front drive wheels  65  and  65 ′. Likewise, cutting assembly means  10  generally includes cutting motor  11 , cutting gear reduction means  15  having a first side and an opposite second side, a first cutting assembly arm  20  and a second cutting assembly arm  21 , a rear cutting wheel  22  and a front cutting wheel  23 . 
     Referring to FIG. 4 showing a side view of the first side of the tire cutting machine, drive motor  51 , which includes rotatable drive motor output shaft  53 , is mounted on drive motor support means  52 , said drive motor support means  52  being attached to body member  2 . Drive gear reduction means  58 , which includes rotatable drive gear reduction input shaft  55 , is mounted on drive means assembly support plate  59 , said drive means assembly support plate  59  being mounted on body member  2 . Drive motor power lead  109  extends from control box  110  to drive motor  51 . In the preferred embodiment, first pulley  54  is mounted on drive motor output shaft  53  by means of a key and keyway, setscrew or other similar locking mechanism (not shown). Similarly, second pulley  56  is mounted on drive gear reduction input shaft  55  by means of a key and keyway, setscrew or other similar locking mechanism (not shown), said second pulley  56  being aligned with first pulley  54 . Rotational force is transmitted from first pulley  54  to second pulley  56  by means of belt  57 . 
     As detailed most clearly in FIG. 10, mounted on the first side of said drive gear reduction means  58  by means of a plurality of mounting bolts  70  is first drive assembly arm  62  having an outside portion and an opposite inside portion, said first drive assembly arm  62  extending horizontally toward the front of the tire cutting machine. First drive assembly arm  62  includes a first aperture  71 , a second aperture  74 , a slotted aperture  73  and a plurality of slotted mounting apertures  72 . As detailed most clearly in FIG. 9, extending horizontally from the first side of drive gear reduction means  58  to an outside end is rotatable first drive gear reduction output shaft  60 , said first drive gear reduction output shaft  60  having threaded aperture  68  extending coaxially into the outside end thereof. First aperture  71  is configured such that first drive gear reduction output shaft  60  may pass freely therethrough. First drive sprocket  61  is mounted on said first drive gear reduction output shaft  60  by means of a key and keyway, setscrew or other similar locking mechanism (not shown), said first drive sprocket  61  being positioned adjacent to the outside portion of first drive assembly arm  62 . In the preferred embodiment, lateral alignment of first drive sprocket  61  on first drive gear reduction output shaft  60  is maintained by set collar  66  and lock bolt  67 , said lock bolt  67  being engaged in threaded aperture  68 . As detailed most clearly in FIG. 11, drive tension sprocket  75  is mounted on drive tension shaft  77 , said drive tension shaft  77  having a first end and an opposite second end. The first end of drive tension shaft  77  passes freely through slotted aperture  73  and is held in position by means of bolt head or nut  76  positioned on said first end of drive tension shaft  77  adjacent to the inside portion of first drive assembly arm  62  and drive tension assembly lock nut  82  positioned on said drive tension shaft  77  adjacent to the outside portion of first drive assembly arm  62 . Drive tension sprocket  75  is positioned near the second end of drive tension shaft  77  and held in lateral alignment with first drive sprocket  61  by means of a pair of sprocket lock nuts  83  and  83 ′. In the preferred embodiment, drive tension sprocket  75  includes an integral roller or ball bearing feature (not shown) known to those skilled in the art to allow free rotation of drive tension sprocket  75  on drive tension shaft  77  with drive tension shaft  77  being held in a fixed position relative to first drive assembly arm  62 . Referring next to FIG. 8, mounted on the inside portion of first drive assembly arm  62  adjacent to second aperture  74  is first drive bearing  78 . Drive wheel shaft  79  is rotatably mounted in first drive bearing  78 , said drive wheel shaft  79  having a first end and an opposite second end. Second aperture  74  is configured such that drive wheel shaft  79  may pass freely therethrough. Second drive sprocket  80  is mounted on said drive wheel shaft  79  by means of a key and keyway, setscrew or other similar locking mechanism (not shown), said second drive sprocket  80  being positioned adjacent to the outside portion of first drive assembly arm  62  and in lateral alignment with first drive sprocket  61  and drive tension sprocket  75 . Rotational force is transmitted from first drive sprocket  61  to second drive sprocket  80  by means of drive assembly chain  81 . In the preferred embodiment of the present invention, drive tension sprocket  75  is engaged to drive assembly chain  81  by loosening drive tension assembly lock nut  82  and moving drive tension shaft  77  along slotted aperture  73  until drive tension sprocket  75  forces drive assembly chain  81  into the desired tension. Drive tension assembly lock nut  82  may then be tightened to maintain such desired tension in drive assembly chain  81  during operation although those skilled in the art will recognize that other tensioning means may be likewise employed. 
     Referring next to FIG. 5 showing a side view of the second side of the tire cutting machine, drive means assembly  50  further includes second drive assembly arm  63  having an outside portion and an opposite inside portion, said second drive assembly arm  63  extending horizontally toward the front of the tire cutting machine and being opposite and in colinear relation to first drive assembly arm  62 . Second drive assembly arm  63  includes a first aperture  86 , a second aperture  88  and a plurality of slotted mounting apertures  87 . Similar to as shown in FIG. 10, second drive assembly arm  63  is mounted on the second side of said drive gear reduction means  58  by means of a plurality of mounting bolts  85  extending through slotted mounting apertures  87 . Mounted adjacent to the outside portion of second drive assembly arm  63  by means of a plurality of shield plate mounting brackets  116  is shield plate  89 , said shield plate  89  having a first aperture  90  and a second aperture  91 . Extending horizontally from the second side of drive gear reduction means  58  to an outside end is rotatable second drive gear reduction output shaft  84 . First aperture  86  of second drive assembly arm  63  and first aperture  90  of shield plate  89  are configured such that second drive gear reduction output shaft  84  may simultaneously pass freely therethrough. As detailed most clearly in FIG. 9, guide wheel  92  is fixably mounted to second drive gear reduction output shaft  84  substantially near the outside end thereof and adjacent to shield plate  89  on the opposite side from second drive assembly arm  63 , said guide wheel  92  having a face on the opposite side from that portion being adjacent to shield plate  89 . Mounted on the face of guide wheel  92  is a plurality of spacer bolts  93  which extend outward a sufficient distance to engage rear drive wheels  64  and  64 ′. In the preferred embodiment, rear drive wheels  64  and  64 ′ each include serrated edges and a plurality of apertures configured to receive spacer bolts  93 . Positioned coaxially around each spacer bolt  93  is a strip spacer  94  and a wheel spacer  95 , said strip spacers  94  being positioned between rear drive wheel  64 ′ and guide wheel  92  and said wheel spacers  95  being positioned between rear drive wheels  64  and  64 ′. Spacer bolts  93  are tightened to secure and lock guide wheel  92  and cutting wheels  64  and  64 ′ in the desired position relative to one another as defined by strip spacers  94  and wheel spacers  95  by using any combination of bolts, nuts and/or threaded apertures obvious and known to those skilled in the art. Mounted on the inside portion of second drive assembly arm  63  adjacent to second aperture  88  is second drive bearing  96 . Drive wheel shaft  79  is further rotatably mounted in second drive bearing  96 . Second aperture  88  is configured such that drive wheel shaft  79  may pass freely therethrough. 
     As detailed must clearly in FIG. 8, in addition to second drive sprocket  80  previously described, centrally mounted on drive wheel shaft  79  between first drive bearing  78  and second drive bearing  96  are front drive wheels  65  and  65 ′, said front drive wheels  65  and  65 ′ being mounted on said drive wheel shaft  79  by means of a key and keyway, setscrew or other similar locking mechanism (not shown). In the preferred embodiment, front drive wheels  65  and  65 ′ each include serrated edges. Lateral alignment of second drive sprocket  80  and front drive wheels  65  and  65 ′ on drive wheel shaft  79  is maintained by means of set collar  97  and lock bolt  98 , said lock bolt  98  being engaged in threaded aperture  99  which extends coaxially into the first end of drive wheel shaft  79  and set collar  100  and lock bolt  101 , said lock bolt  101  being engaged in threaded aperture  102  which extends coaxially into the second end of drive wheel shaft  79 . Spacing along drive wheel shaft  79  is maintained by means of wheel spacers  103  positioned between front drive wheels  65  and  65 ′ and a plurality of alignment spacers  104 . 
     Referring again to FIG.  2  and FIG. 3, bracket  3  is mounted to body member  2  a sufficient distance below drive means assembly  50 , said bracket  3  including lower pin  4 . Mounted between first drive assembly arm  62  and second drive assembly arm  63  of drive means assembly  50  is upper pin  6 . Adjustable brace  5 , which may be a turnbuckle or the like, extends between lower pin  4  and upper pin  6  and is movably mounted to said lower pin  4  and upper pin  6  such that, when first drive arm mounting bolts  70  and second drive arm mounting bolts  85  are loosened, the relative position of front drive wheels  65  and  65 ′ to front cutting wheel  23  maybe adjusted by lengthening or shortening adjustable brace  5  thereby raising or lowering the front portion of drive means assembly  50  by rotating first drive assembly arm  62  and second drive assembly arm  63 , in unison with one another, along slotted mounting apertures  72  and slotted mounting apertures  87  respectively. When front drive wheels  65  and  65 ′ are in the desired position relative to front cutting wheel  23 , first drive arm mounting bolts  70  and second drive arm mounting bolts  85  may be tightened. 
     Referring once again to FIG. 4 showing a side view of the first side of the tire cutting machine, cutting means assembly  10  is vertically disposed above drive means assembly  50  with cutting motor  11  and cutting gear reduction means  15  being mounted on cutting means assembly support plate  12 , said cutting means assembly support plate  12  being mounted on drive gear reduction means  58 . Cutting means assembly  10  is further supported by brace  8  extending between cutting means assembly support plate  12  and drive means assembly support plate  59 . Cutting motor power lead  108  extends from control box  110  to cutting motor  11 . Cutting motor  11  includes rotatable cutting motor output shaft  13  and cutting gear reduction means  15  includes rotatable cutting gear reduction means input shaft  16 . In the preferred embodiment, cutting motor output shaft  13  is fixably connected to cutting gear reduction means input shaft  16  by coupling  14 . 
     As detailed most clearly in FIG. 10, mounted on the first side of said cutting gear reduction means  15  by means of a plurality of mounting bolts  7  is first cutting assembly arm  20  having an outside portion and an opposite inside portion, said first cutting assembly arm  20  extending horizontally toward the front of the tire cutting machine in parallel relation to first drive assembly arm  62  and second drive assembly arm  63 . First cutting assembly arm  20  includes a first aperture  17 , a slotted aperture  18  and a second aperture  19 . As detailed most clearly in FIG. 9, extending horizontally from the first side of cutting gear reduction means  15  to an outside end is rotatable first cutting gear reduction output shaft  24 , said first cutting gear reduction output shaft  24  having threaded aperture  28  extending coaxially into the outside end thereof. First aperture  17  is configured such that first cutting gear reduction output shaft  24  may pass freely therethrough. First cutting sprocket  25  is mounted on said first cutting gear reduction output shaft  24  by means of a key and keyway, setscrew or other similar locking mechanism (not shown), said first cutting sprocket  25  being positioned adjacent to the outside portion of first cutting assembly arm  20 . In the preferred embodiment, lateral alignment of first cutting sprocket  25  on first cutting gear reduction output shaft  24  is maintained by set collar  26  and lock bolt  27 , said lock bolt  27  being engaged in threaded aperture  28 . As detailed most clearly in FIG. 11, cutting tension sprocket  30  is mounted adjacent to slotted aperture  18  by means of cutting tension shaft  31 , said cutting tension shaft  31  having a first end and an opposite second end. The first end of cutting tension shaft  31  passes freely through slotted aperture  18  and is held in position by means of bolt head or nut  29  positioned on said first end of cutting tension shaft  31  adjacent to the inside portion of first cutting assembly arm  20  and cutting tension assembly lock nut  32  positioned on said cutting tension shaft  31  adjacent to the outside portion of first cutting assembly arm  20 . Cutting tension sprocket  30  is positioned near the second end of cutting tension shaft  31  and held in lateral alignment with first cutting sprocket  25  by means of a pair of cutting sprocket lock nuts  33  and  33 ′. In the preferred embodiment, cutting tension sprocket  30  includes an integral roller or ball bearing feature (not shown) known to those skilled in the art to allow free rotation of cutting tension sprocket  30  on cutting tension shaft  31  with cutting tension shaft  31  being held in a fixed position relative to first cutting assembly arm  20 . Referring again to FIG. 8, mounted on the inside portion of first cutting assembly arm  20  adjacent to second aperture  19  is first cutting bearing  34 . Cutting wheel shaft  105  is rotatably mounted in first cutting bearing  34 , said cutting wheel shaft  105  having a first end and an opposite second end. Second aperture  19  is configured such that cutting wheel shaft  105  may pass freely therethrough. Second cutting sprocket  36  is mounted on said cutting wheel shaft  105  by means of a key and keyway, setscrew or other similar locking mechanism (not shown), said second cutting sprocket  36  being positioned adjacent to the outside portion of first cutting assembly arm  20  and in lateral alignment with first cutting sprocket  25  and cutting tension sprocket  30 . Rotational force is transmitted from first cutting sprocket  25  to second cutting sprocket  36  by means of cutting assembly chain  40 . In the preferred embodiment of the present invention, cutting tension sprocket  30  is engaged to cutting assembly chain  40  by loosening cutting tension assembly lock nut  32  and moving cutting tension shaft  31  along slotted aperture  18  until cutting tension sprocket  30  forces cutting assembly chain  40  into the desired tension. Cutting tension assembly lock nut  32  may then be tightened to maintain such desired tension in cutting assembly chain  40  during operation although those skilled in the art will recognize that other tensioning means may be likewise employed. 
     Referring again to FIG. 5 showing a side view of the second side of the tire cutting machine, mounted on the second side of cutting gear reduction means  15  by means of a plurality of mounting bolts  9  is second cutting assembly arm  21  having an outside portion and an opposite inside portion, said second cutting assembly arm  21  extending horizontally toward the front of the tire cutting machine and being opposite and in colinear relation to first cutting assembly arm  20 . Second cutting assembly arm  21  includes a first aperture  42  and a second aperture  43 . Similar to as shown in FIG. 10, second cutting assembly arm  21  is mounted on the second side of said cutting gear reduction means  15 . Extending horizontally from the second side of cutting gear reduction means  15  to an outside end is rotatable second cutting gear reduction output shaft  41 . As detailed most clearly in FIG. 9, shield plate  89  previously described extends upward adjacent to the outside portion of second cutting assembly arm  21 . First aperture  42  of second cutting assembly arm  21  and second aperture  91  of shield plate  89  are configured such that second cutting gear reduction output shaft  41  may simultaneously pass freely therethrough. Rear cutting wheel  22  is mounted to second cutting gear reduction output shaft  41  substantially near the outside end thereof by means of a key and keyway, setscrew or other similar locking mechanism (not shown). Lateral alignment of rear cutting wheel  22  on second cutting gear reduction output shaft  41  is maintained by means of set collar  44  and lock bolt  45 , said lock bolt  45  being engaged in threaded aperture  46  which extends coaxially into the outside end of second cutting gear reduction output shaft  41 . Rear cutting wheel  22  and rear drive wheels  64  and  64 ′ are sized and relatively positioned such that the lower arc of rear cutting wheel  22  passes between the upper arc of rear drive wheels  64  and  64 ′. Mounted on the inside portion of second cutting assembly arm  21  adjacent to second aperture  43  is second cutting bearing  35 . Cutting wheel shaft  105  is further rotatably mounted in second cutting bearing  35 . Second aperture  43  is configured such that cutting wheel shaft  105  may pass freely therethrough. 
     As detailed must clearly in FIG. 8, in addition to second cutting sprocket  36  previously described, centrally mounted on cutting wheel shaft  105  between first cutting bearing  34  and second cutting bearing  35  is front cutting wheel  23 , said front cutting wheel  23  being mounted on said cutting wheel shaft  105  by means of a key and keyway, setscrew or other similar locking mechanism (not shown). Lateral alignment of second cutting sprocket  36  and front cutting wheel  23  on cutting wheel shaft  105  is maintained by means of set collar  37  and lock bolt  38 , said lock bolt  38  being engaged in threaded aperture  39  which extends coaxially into the first end of cutting wheel shaft  105  and set collar  47  and lock bolt  48 , said lock bolt  48  being engaged in threaded aperture  49  which extends coaxially into the second end of cutting wheel shaft  105 . Spacing along cutting wheel shaft  105  is maintained by means of alignment spacers  106 . Front cutting wheel  23  and front drive wheels  65  and  65 ′ are sized and relatively positioned such that the lower arc of front cutting wheel  23  passes between the upper arc of front drive wheels  65  and  65 ′. 
     In the preferred embodiment of the present invention, first pulley  54  and second pulley  56  of drive means assembly  50  are sized such to provide approximately a two-to-one reduction ratio therebetween. Likewise, drive gear reduction means  58  provides a further reduction of approximately sixty-to-one between drive gear reduction input shaft  55  and first and second drive gear reduction output shafts  60  and  84 . Similarly, cutting gear reduction means  15  provides a reduction of approximately twenty-to-one between cutting gear reduction input shaft  16  and first and second cutting gear reduction output shafts  24  and  41 . While these ratios are provided as the preferred embodiment of the present invention, those skilled in the art will recognize that these ratios may be varied without changing the nature and concept of the present invention. 
     Other improvements to the present invention include cutting chain guard  120  and drive chain guard  121  mounted around cutting assembly chain  40  and drive assembly chain  81 , respectively, to increase the safety of the tire cutting machine. Similarly, rear guard  119  is mounted by a plurality of rear guard mounting bolts  122  to shield plate  89  such that said rear guard  119  surrounds rear cutting wheel  22  and rear drive wheels  64  and  641 . In the preferred embodiment, rear guard  119  may be removed and width guide plate  123  installed on rear guard mounting bolts  122 . Width guide plate  123  may be adjusted laterally relative to rear cutting wheel  22  and locked in position by a pair of width guide plate lock nuts  124  mounted on each rear guard mounting bolt  122 , said width guide plate lock nuts  124  being positioned one on either side of width guide plate  123 . 
     In operation, the operator places the main on/off switch  111  in the “on” position thereby starting the rotation of rear cutting wheel  22  and front cutting wheel  23 . The rotation of rear drive wheels  64  and  64 ′ and front drive wheels  65  and  65 ′ may then be started and stopped by alternately depressing and releasing, respectively, foot switch  113 . With main on/off switch  111  in the “on” position, the operator may move a scrap tire, with or without the sidewall previously removed, into the cutting area formed between front cutting wheel  23  and front drive wheels  65  and  65 ′. The operator then engages front drive wheels  65  and  65 ′ by depressing foot switch  113  thereby pulling the scrap tire into said cutting area and cutting said scrap tire into segments. Similarly, with rear guard  119  removed, the operator may move a scrap tire segment which has been previously bisected into the cutting area formed between rear cutting wheel  22  and rear drive wheels  64  and  64 ′. The operator then engages the rear drive wheels  64  and  64 ′ by depressing foot switch  113  thereby pulling the scrap tire segment into said cutting area and further cutting said scrap tire segment into strips. In the event the desired width of the scrap tire strip is less than the distance between rear cutting wheel  22  and guide wheel  92  as previously described, width guide plate  123  may be installed at the desired position such that distance between rear cutting wheel  22  and width guide plate  123  is equal to the desired width of the scrap tire strip. In addition, the operator may move previously cut scrap tire segments or strips into the cutting area formed between front cutting wheel  23  and front drive wheels  65  and  65 ′, using a combination of moving the scrap tire segment and engaging and disengaging front drive wheels  65  and  65 ′ by means of foot switch  113  to obtain a variety of shapes and sizes of scrap tire segments. Thus, the scrap tire cutting machine of the present invention allows the operator to cut a scrap tire into a variety of shapes and sizes which may then be further processed, stored or used for any number of purposes thereby facilitating the ultimate use and disposal of scrap tires.