Self-aligning power transmission belt and system including same

Abstract

A self-aligning power transmission belt that may be used with a corresponding sprocket, and a system including the self-aligning power transmission belt, are described. The self-aligning belt includes a tooth configuration that can eliminate off-tracking errors in belt applications. In some configurations, the self-aligning tape includes two or more rows of teeth, where the teeth in one row are offset from the teeth in the second row.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 402,846, filed on August 31, 2022, entitled “SELF-ALIGNING POWERTRANSMISSION BELTS AND SYSTEMS INCORPORATING THE SAME,” the entire contents of which are incorporated herein by reference. Technical Field

[0004] The present disclosure relates to a self-aligning power transmission belt and corresponding sprocket. More specifically, the self-aligning belt described herein includes a tooth configuration for eliminating tracking errors in belt applications. Background Art

[0006] Belt tracking (i.e., movement of the belt parallel to its axis of rotation) is a common problem experienced by industrial belts, such as power transmission belts. Belt tracking can be caused by variations in belt design and / or manufacturing or application. When belt tracking occurs, the belt may move out of its normal parallel path, in which case the belt path becomes spiral and can push the position of the belt inboard or outboard. In some cases, this effect can be extremely detrimental to the application or the belt.

[0007] One common approach to addressing belt mistracking is to provide flanges on the edges of the sprockets to try to constrain the belt to a specific position range if mistracking occurs. However, this approach increases the cost of the sprockets, which is the most expensive part of the system cost, and does not always prevent mistracking from damaging the belt. For example, in extreme mistracking situations, the belt may travel up the flange and cause additional damage to the belt or the system.

[0008] Another common method to address belt mistracking is to add a center track to the belt. In this method, a groove or channel extending perpendicular to the direction of the teeth is formed in the belt to allow for engagement with a corresponding track or rail located on the sprocket. The interaction between the belt groove / channel and the sprocket track / rail keeps the belt aligned in the application. However, this method results in the removal of tooth surface area and volume, which proportionally reduces the belt's efficiency and requires the belt to be over-designed more for the application by increasing size or structural material. Further, some structural penalties are incurred due to the splitting of a single tooth into two separate and smaller teeth.

[0009] Therefore, there is a need for an alternative belt alignment solution that does not suffer from some or all of the disadvantages present in the aforementioned known techniques. Summary of the invention

[0010] This summary is provided to introduce in simplified form a selection of some concepts that will be further described below in the detailed description. This summary and the foregoing background technology are not intended to identify key aspects or essential aspects of the claimed subject matter. In addition, this summary is not intended to be used to help determine the scope of the claimed subject matter.

[0011] In some embodiments, a power transmission belt is described, the power transmission belt having an axis of rotation and a direction of travel. The power transmission belt includes a first row of spaced apart teeth, the first row being oriented generally parallel to the direction of travel and each of the spaced apart teeth in the first row being oriented generally parallel to the axis of rotation, and a second row of spaced apart teeth, the second row being oriented generally parallel to the direction of travel and each of the spaced apart teeth in the second row being oriented generally parallel to the axis of rotation. The teeth in the second row are offset from the teeth in the first row in a direction generally parallel to the direction of travel.

[0012] In some embodiments, a power transmission belt is described, the power transmission belt having a rotation axis and a travel direction. The power transmission belt includes a first row of spaced apart teeth, the first row being oriented generally parallel to the travel direction and each of the spaced apart teeth in the first row being oriented generally parallel to the rotation axis, a second row of spaced apart teeth, the second row being oriented generally parallel to the travel direction and each of the spaced apart teeth in the second row being oriented generally parallel to the rotation axis, and a third row of spaced apart teeth, the third row being oriented generally parallel to the travel direction and each of the spaced apart teeth in the third row being oriented generally parallel to the rotation axis. The teeth in the first row are aligned with the teeth in the third row in a direction parallel to the rotation axis, and the teeth in the second row are offset from the teeth in the first row and the teeth in the third row in a direction generally parallel to the travel direction.

[0013] In some embodiments, a power transmission system is described, comprising a power transmission belt as described in any of the preceding two paragraphs, and at least one sprocket having teeth configured and arranged to mate with teeth of the power transmission belt.

[0014] These and other aspects of the technology described herein will become apparent after considering the detailed description and drawings herein. However, it should be understood that the scope of the subject matter claimed should be determined by the issued claims, rather than by whether a given subject matter solves any or all of the problems mentioned in the background technology or includes any features or aspects listed in the summary of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Non-limiting and non-exhaustive embodiments of the disclosed technology, including preferred embodiments, are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0016] FIG. 1A is a top view of a power transmission belt known in the prior art.

[0017] FIG. 1B is a side view of a power transmission belt known in the prior art.

[0018] Figure 2 is a top view of a power transmission belt having self-aligning features constructed in accordance with various embodiments described herein.

[0019] Figure 3 is a perspective view of a power transmission belt having self-aligning features constructed in accordance with various embodiments described herein.

[0020] Figure 4 is a top view of a power transmission belt having self-aligning features constructed in accordance with various embodiments described herein.

[0021] Figure 5 is a top view of a power transmission belt having self-aligning features constructed in accordance with various embodiments described herein.

[0022] Figure 6 is a top view of a power transmission belt constructed in accordance with various embodiments described herein.

[0023] Figure 7 is a side view of a power transmission belt constructed in accordance with various embodiments described herein. DETAILED DESCRIPTION

[0025] Embodiments are described more fully below with reference to the accompanying drawings, which form a part of the embodiments and show specific exemplary embodiments by way of example. These embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention. However, the embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. Therefore, the following detailed description should not be considered restrictive.

[0026] 1A and 1B , a portion of a previously known power transmission belt 100 is shown, the belt 100 generally comprising a plurality of spaced apart teeth 110, each of the teeth being aligned in a direction generally parallel to an axis of rotation 101 of the belt 100. The belt 100 has a direction of movement 102, i.e., the direction of movement of the belt when driven by one or more sprockets (not shown), the direction of movement 102 being generally perpendicular to the axis of rotation 101.

[0027] As shown in FIG. 1A , each tooth 110 extends across the width of the belt 100 in a continuous manner, wherein each tooth 110 has no breaks or discontinuities along its width. FIG. 1B shows a side view of the belt 100, wherein the profile of the teeth 110 is shown. The cross-sectional size and dimensions of each tooth 110 are approximately the same, and the spacing between adjacent teeth 110 is approximately constant over the entire length of the belt 100. The gaps or valleys between adjacent teeth 110 are generally where corresponding teeth on the sprocket engage to propel the belt 100 forward. Also as shown in FIG. 1B , the plurality of evenly spaced teeth 101 include a constant pitch P. The pitch P is the distance between the center of one tooth and the center of an adjacent tooth.

[0028] As discussed in more detail in the Background, a problem that a belt 100 constructed as shown in FIGS. 1A and 1B may suffer from is belt mistracking, wherein as the belt rotates about its axis of rotation, the belt moves or slides parallel to the axis of rotation rather than remaining in position without lateral movement. The belt construction shown in FIGS. 1A and 1B does not prevent such mistracking, at least in part because there is nothing in the tooth profile to prevent lateral movement of the belt.

[0029] Reference now Figure 2 and 3 , shows an embodiment of a power transmission belt 200 in which the tooth profile is arranged to help inhibit and prevent belt deviation. Figure 2 and 3 In the belt configuration shown in , the belt 200 is generally divided into at least two rows, which are oriented parallel to the direction of movement 202 . Figure 2 A belt 200 is shown having three rows 200A, 200B, 200C, but it should be understood that the belt may have only two rows (see, e.g. Figure 5 ), or three or more rows (see e.g. Figure 4 ). In the first row 200A, teeth 210A having the same cross-sectional shape and size are spaced at uniform intervals along the length of the row 200A and have a width substantially equal to the width of the row 200A. The width of the row 200A is less than the overall width of the belt 200, so the teeth 210A do not extend across the entire width of the belt 200.

[0030] In a second row 200B, which may be laterally adjacent to the first row 200A, teeth 210B having the same cross-sectional shape and size are spaced at uniform intervals along the length of the row 200B and have a large width equal to the width of the row 200B. The width of the row 200B is less than the overall width of the belt 200, so the teeth 210B do not extend across the entire width of the belt 200. However, compared to the belt configuration shown in Figures 1A and 1B, the teeth 210B in the row 200B are offset from the teeth 210A in the row 200A in a direction parallel to the direction of movement 202. The offset 220 is the distance between the leading edge of the tooth 210A in the row 200A and the leading edge of the laterally adjacent tooth 210B in the row 200B.

[0031] Generally speaking, the above configuration can help inhibit or prevent the belt from swerving because the teeth in a given row on the belt 200 hit the sides of the teeth in the laterally adjacent row of the corresponding sprocket when the belt 200 moves laterally, thereby hindering the lateral movement of the belt. In other words, when used with the corresponding sprocket, the disclosed configuration eliminates a straight path that the teeth on the belt may traverse when the belt moves laterally.

[0032] The width of each row disposed on the belt 200 is generally not limited. In some embodiments, each row has the same width, while in other embodiments, one or more rows may have a different width than other rows disposed on the belt. Figure 3 As shown in FIG. , the belt 300 generally includes three rows 300A, 300B, 300C, each of which is approximately one-third of the width of the belt 300. In addition, Figure 3 An embodiment is shown in which the row 300B containing the offset teeth is centered across the width of the belt 300, thereby occupying the middle third of the belt 300. However, it should be understood that the location of the offset row is not limited to the center of the belt 300. In one example of an asymmetric configuration (not shown), the first row may have a width that is one-third of the width of the belt, the third row may have a width that is half the width of the belt, and the second row containing the offset teeth and positioned between the first and third rows may have a width that is one-sixth of the width of the belt. In this configuration, each row has a different width, and the offset row is not centered across the width of the belt.

[0033] In some embodiments, the pitch P is the same in each row disposed on the belt, regardless of any offset. The offset 220 can be any value less than one pitch P, thereby ensuring that the teeth in the offset row are not aligned with the teeth in the non-offset row. In some embodiments, the offset 220 is 25% of the pitch P, 33% of the pitch P, 50% of the pitch P, 66% of the pitch P, or 75% of the pitch P, or any other value less than 100% of the pitch.

[0034] In some embodiments, the particular offset 220 for the offset row is selected so that each tooth in the offset row still contacts at least one tooth in the laterally adjacent row. Figure 2 , where each tooth 210B in row 200B contacts at least one tooth 210A in row 200A. Figure 2 As shown in FIG. 1 , each tooth 210B contacts two teeth 210A in row 200A. On the other hand, Figure 3 A configuration is shown in which each tooth in row 300B contacts one tooth in row 300A. This embodiment, in which teeth in offset rows contact teeth in non-offset rows, helps ensure that the tooth configurations described herein do more than simply provide a plurality of individual teeth of smaller width. At least some volume continuity between teeth in laterally adjacent rows provides at least some contribution to structural integrity between teeth, which in turn helps provide improved durability to the belt.

[0035] In some embodiments, all teeth in the deviated and non-deviated rows have the same cross-sectional shape and size. For example, each tooth on the belt can have a generally square cross-sectional shape, with the same height and length. The consistency of tooth shape and size helps maximize the surface area of ​​the belt in contact with the sprocket at any time. The specific cross-sectional shape and size used are not limited. Illustrative but non-limiting examples of suitable cross-sectional shapes include square, chamfered, rounded, etc.

[0036] In alternative embodiments, the cross-sectional shape and / or size of the teeth in one or more deviated rows may be different from the cross-sectional shape and / or size of the teeth in the non-deviated rows. For example, in such an embodiment, the teeth in the non-deviated rows may have a square cross-sectional shape, while the teeth in the deviated rows may have a rounded cross-sectional shape.

[0037] Figure 4 Shown with Figure 2 , but wherein the belt 400 includes two offset rows and three non-offset rows, for a total of five rows in the belt 400. More specifically, the belt 400 includes rows 400A, 400B, 400C, 400D, and 400E, which include spaced-apart teeth 410A, 410B, 410C, 410D, and 410E, respectively. The teeth 410B, 410D in rows 400B and 400D are offset in a direction parallel to the direction of travel of the belt 400 by a distance less than the pitch of the spaced-apart teeth 410A, 410C, 410E in rows 400A, 400C, and 400E. In this way, Figure 4 An embodiment is shown in which more than one row of spaced apart teeth are offset. Figure 4 It is also shown that the widths of rows 400A-400E may vary, with rows 400B and 400D being wider than rows 400A, 400C, and 400E.

[0038] Figure 5 An embodiment is shown in which the belt 500 includes a total of two rows, one of which is offset from the other. More specifically, the belt 500 includes rows 500A and 500B, which include spaced teeth 510A and 510B, respectively. The teeth 510B in row 500B are offset in a direction parallel to the direction of travel of the belt 500 by a distance less than the pitch of the spaced teeth 510A in row 500A. In this way, Figure 5 An embodiment is shown in which an offset row of spaced apart teeth is not bounded on both sides by a non-offset row of teeth. Figure 5 Rows 500A and 500B are shown as having different widths, but it should be understood that in alternative embodiments, the width of row 500A may be the same as the width of row 500B.

[0039] Any method of manufacturing the self-aligning belt described herein can be used, as long as the desired deviated tooth row is provided. In some embodiments, the self-aligning belt described herein is manufactured using standard belt molding techniques, wherein the mold contains one or more rows of desired deviated teeth. In some embodiments, the same mold is used to prepare a separate tooth row, and the tooth rows are then sewn together or otherwise attached to each other to form a composite belt structure. One or more tooth rows for providing deviated teeth in the belt can be aligned relative to the non-deviated tooth row before being sewn or otherwise attached together, so as to provide the composite belt with one or more rows of spaced teeth of the desired deviated tooth.

[0040] In embodiments where teeth in an offset row contact at least one tooth in a non-offset row, the molding manufacturing technique provides a degree of integral or unitary connection between adjacent offset teeth and non-offset teeth, and thus may provide better structural integrity than other manufacturing techniques, such as sewing individual rows of teeth together. Techniques that sew or otherwise bond individual rows of teeth together may still provide the desired contact between teeth in adjacent rows, but the teeth are distinct and do not have material flow from one tooth to another. Therefore, the presence of seams or breaks between teeth may result in poor structural integrity.

[0041] Another way to make a self-aligning power transmission belt as described herein can include preparing or providing a primary toothed power transmission belt having at least one groove formed therein, the groove being aligned parallel to the direction of travel of the belt, extending around the entire periphery of the belt, and having a depth that does not exceed the thickness of the primary power transmission belt. By forming at least one groove in the primary power transmission belt in this manner, a secondary toothed belt can be disposed in the groove. The secondary toothed belt disposed in the groove can be rotationally positioned within the groove so that the teeth of the secondary toothed belt are not aligned with the intermittent teeth of the primary power transmission belt, thereby providing at least one offset tooth row in a manner similar or identical to the previous embodiments.

[0042] Figure 6 A general illustration of this embodiment is provided. More specifically, Figure 6 A main power transmission belt 600 having grooves 650 formed therein, a secondary toothed belt 660 , and a composite power transmission belt 670 made by disposing the secondary toothed belt 660 in the grooves 650 of the main power transmission belt 600 are shown.

[0043] and Figure 2 Similar to the power transmission belt 200 shown in FIG. 1 , the main power transmission belt 600 includes a first row 600A of teeth 610A and a third row 600C of teeth 610C. However, instead of including Figure 2 600, the main power transmission belt 600 at least initially includes a groove 650 in which no teeth are disposed. Although the teeth 610A in the first row 600A and the teeth 610C in the third row 600C are aligned in a direction parallel to the rotational axis of the main power transmission belt 600 and may have the same cross-sectional shape, size and dimensions, due to the presence of the groove 650, the teeth 610A and 610C do not extend across the entire width of the main power transmission belt 600.

[0044] The main power transmission belt 600 may include the groove 650 as a result of molding using a mold that creates the groove 650, or the groove 650 may be formed by removing a portion of the teeth provided in an initial version of the main power transmission belt 600. For example, the main power transmission belt 600 may be formed by taking a belt similar to the belt 100 shown in FIG. 1A and removing a central portion of the teeth 110 to thereby create the groove 650.

[0045] Regardless of how the grooves 650 are formed, the grooves 650 are generally configured so that their depth does not exceed the thickness of the main power transmission belt 600. In some embodiments, the depth of the grooves 650 is such that the bottom of the grooves 650 is at or below the lowest point of the valley between adjacent teeth 610 in the same row in the main power transmission belt 600. In some embodiments where the power transmission belt 600 includes a backing layer having the teeth 610 formed thereon, the grooves 650 extend to the backing layer so that no tooth material is present in the grooves 650.

[0046] The width of the groove 650 is generally not limited. Figure 6 As shown in FIG. 6 , the groove 650 is generally about one-third of the width of the main power transmission belt 600. However, the groove 650 can be larger or smaller than this amount. Similarly, although Figure 6 A single groove 650 is shown formed in the primary power transmission belt 600 , but it should be understood that the primary power transmission belt 600 may include more than one groove 650 .

[0047] The auxiliary toothed belt 660 is generally configured so that the auxiliary toothed belt 660 can be disposed in the groove 650 of the main power transmission belt 600. In some embodiments, the width of the auxiliary toothed belt 660 can be approximately equal to the width of the groove 650 so that the auxiliary toothed belt 660 substantially occupies the entire width of the groove 650 when disposed in the groove 650. In some embodiments, the width of the auxiliary toothed belt 660 can be such that when disposed in the groove 650, the sides of the teeth 661 of the auxiliary toothed belt 660 contact the sides of the teeth 610 in the main power transmission belt 600.

[0048] The secondary toothed belt 660 may also be configured so that its inner diameter is approximately equal to the diameter of the primary power transmission belt 600 at the groove 650. In this manner, the inner diameter of the secondary toothed belt 660 directly abuts the bottom of the groove 650. In some embodiments, the inner diameter of the secondary toothed belt 660 may sufficiently match the diameter of the primary power transmission belt 600 in the groove so that no additional fasteners are required to secure the secondary toothed belt 660 to the primary power transmission belt 600. Regardless of this fit, fasteners such as glue or adhesive may be used to further secure the secondary toothed belt 660 to the primary power transmission belt 600.

[0049] The size, shape, dimensions, number, spacing, and profile of the teeth 661 of the auxiliary toothed belt 660 are generally not limited, as long as the orientation, shape, size, spacing, etc. of the teeth 661 help to inhibit lateral movement of the composite belt 670 when it is engaged with the sprocket when the auxiliary toothed belt 660 is disposed in the groove 650 of the main power transmission belt 600. Figure 6As shown in FIG. 6 , teeth 661 are generally configured to be similar or identical to teeth 610A, 610B of main power transmission belt 600 in terms of shape, cross-sectional profile, spacing, and size. In such embodiments where teeth 661 are similar or identical to teeth 610A, 610C, composite belt 670 is similar to Figure 2 and 3 In order to provide the desired inhibition of lateral movement of the belt 670 when meshing with the sprocket, such an embodiment in which the teeth 661 are identical to the teeth 610A, 610C requires that the auxiliary toothed belt 660 be disposed in the groove 650 so that the teeth 661 are not aligned with the teeth 610A, 610C in a direction parallel to the rotational axis of the composite belt 670. In other words, the auxiliary toothed belt 660 is rotationally offset from the main power transmission belt 600 so that the teeth 661 are not aligned with the teeth 610A, 610C.

[0050] Although in some embodiments, teeth 661 can be similar or identical to teeth 610A, 610C, it should be understood that teeth 661 need not be identical to teeth 610A, 610C. For example, teeth 661 can have a different profile, different dimensions, different sizes, and / or different spacing than teeth 610A, 610C. Figure 7 An illustration of an embodiment is provided in which the teeth 661 of the secondary toothed belt 660 differ significantly from the teeth 610A, 610C of the primary power transmission belt 600 in several respects. For example, Figure 7 Teeth 661 are shown as being taller, thinner, and closer together than teeth 610A. Figure 7 It is shown that despite the differences between teeth 661 and 610A, teeth 661 are positioned relative to teeth 610A, 610C such that they will still effectively inhibit lateral movement of composite belt 670 when engaged with the sprockets.

[0051] The materials used to form the main power transmission belt 600 and the auxiliary toothed belt 660 are generally not limited. Regarding the materials used for the teeth 610A, 610C of the main power transmission belt 600 and the teeth 661 of the auxiliary toothed belt, the materials of the teeth 610A, 610C, and 661 may be the same material, or the materials of the teeth 610A, 610C may be different from the materials used for the teeth 661. In addition, an additional layer may or may not be provided on any of the teeth 610A, 610C, and 661. Figure 7 As shown in FIG. 6 , the cover layer 680 is disposed on the tooth 610A, while the tooth 661 does not include the cover layer.

[0052] By implementing the above-described embodiments, several advantages may be achieved, including: elimination or reduction of belt deviation; improved power transfer efficiency by increasing the surface area compared to, for example, a center track belt; improved power transfer efficiency by increasing the surface area through the use of a misaligned tooth pattern compared to a standard toothed belt; the ability to use narrower belts and / or reduce the type or amount of material used in the belt due to the aforementioned improvement in power transfer efficiency; and more continuous power transfer due to the increase in the number of teeth meshing with the sprocket at any time.

[0053] In summary, it will be appreciated that specific embodiments of the present invention have been described for purposes of illustration, but that various modifications may be made without departing from the scope of the present invention. Accordingly, the present invention is not to be limited except as in the appended claims.

[0054] Although the technology has been described in language specific to certain structures and materials, it should be understood that the invention defined in the appended claims is not necessarily limited to the specific structures and materials described. Instead, specific aspects are described as forms of implementing the claimed invention. Because many embodiments of the invention can be practiced without departing from the spirit and scope of the invention, the invention resides in the claims appended hereto.

[0055] Unless otherwise indicated, all numbers or expressions used in the specification (except for the claims), such as those expressing dimensions, physical properties, etc., should be understood to be modified by the term "approximately" in all cases. At least, and without attempting to limit the application of the doctrine of equivalents of the claims, each numerical parameter modified by the term "approximately" cited in the specification or claims should at least be interpreted according to the number of significant digits listed and by applying rounding techniques. In addition, all ranges disclosed herein should be understood to include and support claims that list any and all subranges or any and all single values ​​contained therein. For example, the range of "1 to 10" set forth should be considered to include and support claims that list any and all subranges or single values ​​between and / or including a minimum value of 1 and a maximum value of 10; that is, all subranges starting with a minimum value of 1 or greater and ending with a maximum value of 10 or less (e.g., 5.5 to 10, 2.34 to 3.56, etc.) or any value between 1 and 10 (e.g., 3, 5.8, 9.9994, etc.).

Claims

1. A power transmission belt having a rotation axis and a travel direction, comprising: a first row of spaced-apart teeth, the first row oriented generally parallel to the direction of travel and each of the spaced-apart teeth oriented generally parallel to the axis of rotation, the first row of spaced-apart teeth having a width less than a width of the power transmission belt; as well as a second row of spaced-apart teeth, the second row oriented generally parallel to the direction of travel and each of the spaced-apart teeth oriented generally parallel to the axis of rotation, the second row of spaced-apart teeth having a width less than a width of the power transmission belt; wherein the teeth in the second row are offset from the teeth in the first row in a direction substantially parallel to the direction of travel.

2. The power transmission belt according to claim 1, wherein: The second row of spaced apart teeth is offset from the first row of spaced apart teeth by less than a pitch of the first row of spaced apart teeth.

3. The power transmission belt according to claim 2, wherein: The second row of spaced apart teeth is offset from the first row of spaced apart teeth by approximately half the pitch of the first row of spaced apart teeth.

4. The power transmission belt according to claim 1, wherein: Each tooth in the first row of spaced-apart teeth contacts at least one tooth in the second row of spaced-apart teeth.

5. The power transmission belt according to claim 1, wherein: The second row of spaced apart teeth is centered across the width of the power transmission belt.

6. The power transmission belt according to claim 5, wherein: The side edges of the first row of spaced-apart teeth serve as side edges of the power transmission belt.

7. The power transmission belt according to claim 1, wherein: The sum of the width of the first row and the width of the second row is equal to the width of the power transmission belt.

8. The power transmission belt according to claim 1, wherein: The cross-sectional shape and size of each tooth in the first row of spaced-apart teeth and the spacing between teeth are the same as the cross-sectional shape and size of each tooth in the second row of spaced-apart teeth and the spacing between teeth.

9. The power transmission belt according to claim 1, wherein: The cross-sectional shape of each tooth in the first row of spaced-apart teeth is different from the cross-sectional shape of each tooth in the second row of spaced-apart teeth.

10. A power transmission belt having an axis of rotation and a direction of travel, comprising: a first row of spaced-apart teeth, the first row oriented generally parallel to the direction of travel and each of the spaced-apart teeth oriented generally parallel to the axis of rotation, the first row of spaced-apart teeth having a width less than a width of the power transmission belt; a second row of spaced-apart teeth, the second row oriented generally parallel to the direction of travel and each of the spaced-apart teeth oriented generally parallel to the axis of rotation, the second row of spaced-apart teeth having a width less than a width of the power transmission belt; as well as a third row of spaced-apart teeth, the third row oriented generally parallel to the direction of travel and each of the spaced-apart teeth oriented generally parallel to the axis of rotation, the third row of spaced-apart teeth having a width less than a width of the power transmission belt; wherein the teeth in the first row are aligned with the teeth in the third row in a direction parallel to the rotational axis; and wherein the teeth in the second row are offset from the teeth in the first row and the teeth in the third row in a direction substantially parallel to the direction of travel.

11. The power transmission belt according to claim 10, wherein: The second row of spaced apart teeth is offset from the first and third rows of spaced apart teeth by less than a pitch of the first and third rows of spaced apart teeth.

12. The power transmission belt according to claim 11, wherein: The second row of spaced apart teeth is offset from the first row of spaced apart teeth and the third row of spaced apart teeth by approximately half the pitch of the first row of spaced apart teeth.

13. The power transmission belt according to claim 10, wherein: Each tooth in the second row of spaced-apart teeth contacts at least one tooth in the first row of spaced-apart teeth and at least one tooth in the third row of spaced-apart teeth.

14. The power transmission belt according to claim 10, wherein: The second row of spaced apart teeth is centered across the width of the power transmission belt.

15. The power transmission belt according to claim 14, wherein: A side edge of the first row of spaced apart teeth serves as a first side edge of the power transmission belt, and a side edge of the third row of spaced apart teeth serves as a second side edge of the power transmission belt opposite the first side edge of the power transmission belt.

16. The power transmission belt according to claim 10, wherein: The second row has a width that is approximately one third of the width of the power transmission belt.

17. The power transmission belt according to claim 10, wherein: The sum of the width of the first row, the width of the second row, and the width of the third row is equal to the width of the power transmission belt.

18. The power transmission belt according to claim 10, wherein: The cross-sectional shape and size of each tooth in the second row of spaced-apart teeth and the spacing between teeth are the same as the cross-sectional shape and size of each tooth in the first row of spaced-apart teeth and the third row of spaced-apart teeth and the spacing between teeth.

19. The power transmission belt according to claim 10, wherein: The cross-sectional shape of each tooth in the second row of spaced-apart teeth is different from the cross-sectional shape of each tooth in the first row of spaced-apart teeth and the third row of spaced-apart teeth.

20. A composite power transmission belt having an axis of rotation and a direction of travel, comprising: Main power transmission belt, including: a first row of spaced-apart teeth, the first row oriented generally parallel to the direction of travel and each of the spaced-apart teeth oriented generally parallel to the axis of rotation, the first row of spaced-apart teeth having a width less than a width of the power transmission belt; a third row of spaced-apart teeth, the third row oriented generally parallel to the direction of travel and each of the spaced-apart teeth oriented generally parallel to the axis of rotation, the third row of spaced-apart teeth having a width less than a width of the power transmission belt; and a groove between the first row of spaced apart teeth and the third row of spaced apart teeth, the groove having a groove width; and Auxiliary toothed belt, comprising: a series of spaced apart teeth oriented generally parallel to the axis of rotation, each tooth in the series of spaced apart teeth extending across a width of the secondary toothed belt; The auxiliary toothed belt has a width approximately equal to the groove width, and is disposed in the groove such that teeth of the auxiliary toothed belt are substantially misaligned with teeth in the first row of spaced-apart teeth and the third row of spaced-apart teeth in a direction generally parallel to the rotational axis.

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