text: referring to fig2 a pulley is shown using polygonal , wedge - shaped lobes 11 equally spaced radially 90 degrees apart in a four - lobe format . referring now to fig3 each lobe contains an apex 13 and three sides , including a curved circumferential face 15 portion , and two flat radial side portions 17 . the three corners of each lobe are radiased to minimize the radius of wrap required by the drive belts . the circumferential face 15 of each lobe subtends an arc of approximately 90 degrees measured at the axis of rotation as indicated in fig5 . the 90 degree lobe shape is theoretically optimal regardless of the number of lobes employed per pulley . using this shape , mechanical leverage of the pulleys is maximized over the greatest extent of rotation . other shapes may be used depending upon the requirements of the system and a solid lobe may be replaced by separate pins 39 at the three corners as shown in fig9 . however , the solid lobe design is structurally stronger . if a belting material 41 is used which is sensitive to angle of wrap , a lobe having greater radius corners or even a circular cross - section as shown in fig7 may be used with some sacrifice of torque transmission capability . referring again to fig2 four drive lobes 11 are mounted on a common core sleeve 19 which has an open bore 21 for routine shaft mounting . spacer plates 23 are located between adjacent drive lobes to limit the axial movement of the drive belting 41 . the core sleeve 19 circumference contains a square cross - section portion 25 for engaging like apertures 27 in both the spacer plates and lobes . the lobes are located with the apex of each lobe as close to the axis of rotation 43 as possible . this maximizes the mechanical advantage between the pulleys and belts . referring to fig4 the lobes and spacer plates may either be force fit on the core sleeve or axially secured between collar means 47 on one end and a second collar 45 on the opposite end . in fig4 the spacer plates and drive lobes are affixed together , and this subassembly as a unit 29 is permitted to move axially along core sleeve 19 because of lateral spaces 31 which allow the operational elements of the pulley to be self - centering . referring to fig1 , the drive lobes 11 may contain an endless groove 33 around their lateral periphery to ensure the centering of the drive belts 41 . the groove 33 is for alignment purposes only and therefore should be substantially greater in width than the width of the drive belt 41 to minimize contact area . the drive belts 41 are preferably made of synthetic - type materials , such as glass , kevlar ( r ), spectra ( r ), or a graphite fiber . the main requirement of the drive belting of this invention is that the material be extremely strong and light , yet flexible . this permits the pulleys to be spaced a great distance apart without creating excessive slack in the drive belting . also , the belts require only a small amount of preloaded tension and may operate at very high r . p . m . in an alternate embodiment of the present invention , elastic or highly resilient drive belts are used to create a power transmission system which can absorb shock and vibration yet transmit a surprising amount of power without slippage . also , this system can adjust to extreme changes in the distance between coupled pulleys during operation without slippage or interruption and without excessive wear or damage to the drive belts . fig8 shows a drive lobe having sides consisting of three equal arcs . this design combines a three - sided polygonal efficiency and maintains equal spacing between upper and lower runs of the belting during operation . referring now to fig5 and 6 , in another alternate embodiment of the present invention , a belt - engaging spring clip 37 is added to the apex of each drive lobe to provide additional drive belt tension . these added structures may be useful to take up drive belt slack during periods of clutching . furthermore , as shown in fig7 the belt may make a plurality of turns about each lobe to also control belt movement during clutching with or without the addition of the spring clip structure . in yet another alternate embodiment of the present invention , drive belts are constructed only from multiple wraps of a single strand or fiber bundle which are bonded together with a suitable agent or simply knot tied at loose ends . a drive belt of this type should have a generally circular cross - section to minimize lobe contact area as shown in fig1 . fig1 and 12 show an embodiment wherein outer friction belt 49 is laid over the exterior of two opposing pulleys in a drive system . this additional friction belt is particularly useful in clutching systems in order to both contain the inner belting and also to bring the driven pulley up to speed upon initial engagement . thereafter , the pulleys are synchronized and phase locked by the inner belting which operates on the eccentric elements . this added belt need not transmit any power after the pulleys are fully engaged and therefore it can be a very light weight and flexible material . it should be understood that while the preferred embodiment disclosed shows an assembly of parts , the equivalent structure may be created from a molding process to create a pulley of unitary construction . the present invention has many novel operating characteristics . as mentioned , power transmission between shafts is by way of rolling friction only . this yields the advantages of extremely high efficiency , high r . p . m ., with a wide selection of materials . for instance , materials may be chosen to have corrosion resistance without having to meet the frictional requirements of a belt system or lubrication requirements of a chain system . materials are selected only for their strength , light weight , and flexibility . frictional coefficients and melt point are not necessarily concerns , except that in most embodiments friction is to be avoided as it can affect operating efficiency . to reduce friction , a coating may be added to the belt - engaging surfaces of the pulleys . a surprising and unique aspect of the present invention is that each belt is only under tension for a portion of each 360 - degree rotation of each pulley , namely for approximately 180 degrees . there is therefore a period of tension and a period of relaxation through all elements of each belt within each revolution even through rotary motion is continuous . this operating characteristic is particularly useful when the belting is wound a plurality of turns around each lobe for belt control as indicated in fig7 . in this configuration , a belt 41 with some stiffness , such as a light metal wire , should be used so there is a lateral coil pressure of the wire along the surface of the lobes . the lobes in this embodiment should have a circular cross - section . this lateral coil pressure separates the turns of wire on the lobe to prevent doubling over and binding . during the slack period of each rotation , there is no tension on the wire and the lateral coil pressure is sufficient to move the belting along the face of the lobe to prevent overlapping . this is a unique operating characteristic of the present invention which is possible only because individual belt tension is intermittent , even though the belts as a group provide a continuous and even delivery of turning force to the driven pulley . another novel operating characteristic of the present invention is that the pulleys may be clutched into and out of engagement without losing the relative timing between the driving and driven shafts . clutching may be achieved by simply changing the distance between the shafts . in a power transmission system which is designed for clutching , the additional outer belt and sheaves as shown in fig1 may be added in order to help bring the driven pulley up to speed before the engagement point of the inner belting is reached . the additional belt , because it surrounds the outer circumference of both pulleys as a normal v - belt would , helps keep the inner belting from jumping off of their respective drive lobes . the power transmission system disclosed herein may be particularly useful as a drive system used in corrosive atmospheres , including sea coast sites , marine applications , and chemical or industrial plants . furthermore , it should be noted that for a given diameter of pulley , the instant invention transfers a much greater amount of turning force or torque than a standard v - belt and also the driving and driven shafts remain positively coupled without any slippage so long as the material strength of the system is not exceeded . the light belting accommodates a tight wrap angle and therefore small diameter pulleys can be used with great efficiency . because each pulley is in perfect dynamic balance and the belting extremely light , the r . p . m . capability of this system far exceeds prior art power transmission systems . one embodiment of the present invention as shown in fig5 and 6 employs the addition of belt - engaging springs 37 fitted over the apex of each drive lobe 13 . this spring engages the drive belt and helps take up drive belt slack during periods of clutching . even without the inclusion of these springs , however , the present invention tolerates a great deal of change in the distance between the drive shafts . surprisingly , the oscillating motion of the belts by the drive lobes creates a whipping action at high r . p . m . and therefore the belts become self - tensing at speed . another major benefit of the present invention is its economy of manufacture . because of the simplicity of each of the components , the strong structural design , and the limited requirements of each component , the system may be constructed from very inexpensive materials . for example , the pulleys may be molded of plastic and used in small diameters . in the prior art , plastic can only be used for larger diameter ( i . e . slower belt speed , and greater wrap angle ) applications because of heating due to slippage and the low melt point of the plastic . also , as mentioned , the belting may be simply multiple - wrap loops of a single strand of fiber simply knot tied at loose ends . this permits replacing a broken drive belt by hand - making the item inexpensively and quickly onsite from raw materials . commonly available nature fibers , such as cotton , may be used . while the above description contains many specificities , they should not be considered as limitations upon the scope of the present invention but rather of examples of preferred embodiments thereof . many other variations altering scale and geometry , among other factors , are possible . the present invention is to be defined only by the appended claims and their legal equivalents .