Abstract:
This hybrid pulley assembly is comprised of two outer driven synchronized timing pulleys and a centerpiece inner driver timing pulley. This pulley assembly operates in such a manner where the input driving timing belt mounted on the centerpiece timing pulley positively drives the outer synchronized timing pulleys. An outer driven timing belt, which is mounted on the outer driven timing pulleys and across the centerpiece driver timing belt, is partially supported by the centerpiece driver timing belt top surface in the area enclosed by the two outer synchronized timing pulleys. This configuration allows this hybrid pulley assembly to be driven from within. This alleviates the need of conventional drive train systems where a timing driven belt is driven through an axial input to the driven timing pulley.

Description:
BACKGROUND OF INVENTION  
       [0001]     This invention applies to “A Belt and Pulley Positive Drive System.” The field of this invention falls within the U.S. patent Classification Definition of “CLASS 474 ENDLESS BELT POWER TRANSMISSION SYSTEMS” OR COMPONENTS “Subclass “152 POSITIVE DRIVE PULLEY OR GUIDE ROLL”.  
         [0002]     The problems related to Timed Pulleys, which this invention provides a solution to, are as follows:  
         [0003]     When the Pulley(s) in a timed belt driven system is mounted in a confined space, there maybe no provision to drive the Pulley directly by means of a motor connected shaft mounted or connected to the timing pulley.  
         [0004]     When the timing belt is cleated or the non-timed side of the belt not being Flat, the belt cannot be driven by friction applied through a tensioned pulley connected to the driving motor or gear head. This constraint coupled with limited space around the timing pulley makes it impossible for a direct drive to this said pulley.  
       SUMMARY OF INVENTION  
       [0005]     This invention constitutes of Three Timing Pulleys where the Centerpiece-Timing Pulley is driving the Outer-Timing Pulleys. The Centerpiece Timing Pulley does not have to be synchronized with respect to the Outer-Timing Pulleys. However, the Outer-Timing Pulleys are synchronized with respect to each other.  
         [0006]     This allows the drive (whether a motor shaft or gear head) to be remotely located from the Centerpiece-Timing Pulley when the space around the Outer Timing Pulleys is confined and/or the timing belt does not have a flat surface to which a friction drive mechanism could be applied. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0007]      FIG. 1 : The Apparatus displayed on  FIG. 1  shows the three pieces of the Timing Pulley Assembly placed on top of each other. The only purpose for this Figure is to display the Centerpiece-Timing Pulley&#39;s  2  position within the above-mentioned Three Piece Timing Pulley Assembly.  
         [0008]      FIG. 2 : The Apparatus according to  FIG. 2  displays all the characteristics of  FIG. 1  with one added feature. This added feature has provisions for proper Outer-Timing Pulleys&#39;  4  &amp;  6  Synchronization. The machined drive shaft bore and key way throughout the entire Three Piece Timing Pulley Assembly achieves this Timed Synchronization. All items discussed in this said Brief  FIG. 2  are described and shown on this said Figure.  
         [0009]      FIG. 3 : The Apparatus according to  FIG. 3  displays all the characteristics of  FIG. 2  with one added feature and one removed feature. This added feature has provisions for proper Outer-Timing Pulleys&#39;  8  &amp;  30  Synchronization. The installed three Roll-Pins  14  or Dowel Pins  14  throughout the entire Three Piece Timing Pulley Assembly achieves this Timed Synchronization. The key way feature has been removed in this said Figure. View III of this said  FIG. 3  shows a sectional view of this said Hybrid Pulley Assembly with the Drive Shaft  90  removed for clarification of the location of the third Dowel Pin  14 . All items discussed in this said Brief  FIG. 3  are described and shown on this said Figure.  
         [0010]      FIG. 4 : The Apparatus according to  FIG. 4  displays all the characteristics of  FIG. 2  with one added features and one removed feature. This added feature has provisions for proper Outer-Timing Pulleys&#39;  9  &amp;  11  Synchronization. The installed Three Mounting Screws throughout the entire Three Piece Timing Pulley Assembly achieves this Timed Synchronization. The removed feature is the key way in this said Figure. View IV of this said  FIG. 4  shows a sectional view of this said Hybrid Pulley Assembly with the Drive Shaft  90  removed for clarification of the location of the third Machine Screw  13 . All items discussed in this said Brief  FIG. 4  are described and shown on this said Figure.  
         [0011]      FIG. 5 : The Apparatus according to  FIG. 5  displays all the characteristics of  FIG. 2  with two added features and one removed feature. This first added feature has provisions for proper Outer-Timing Pulleys&#39;  50  &amp;  51  Synchronization. The installed three Mounting Screws  13  located throughout the entire Three Piece Timing Pulley Assembly, achieves this Timed Synchronization. The second added feature is the Mounting Shaft Bearings  12 . The removed feature is the key way in this said Figure. View V of this said  FIG. 5  shows a sectional view of this said Hybrid Pulley Assembly with the Drive Shaft  90  removed for clarification of the location of the third Machine Screw  13 . All items discussed in this said Brief  FIG. 5  are described and shown on this said Figure.  
         [0012]      FIG. 6 : The Apparatus according to  FIG. 6  displays one Hybrid Pulley Assembly, one Inner Drive Timing Belt  16 , and one Outer Driven Timing Belt  15 . On this said Figure number  6 , one of the applications of this hybrid pulley assembly is illustrated. This said application is displayed on  FIG. 6 . There is only one Driven Outer Timing Belt  15  used for a selected process.  
         [0013]      FIG. 6 : The Apparatus according to  FIG. 6  also displays the capability of driving this said Hybrid Pulley Assembly from within the Assembly. This said internal Centerpiece-Timing Pulley  5  will provide the power to the Outer Timing Pulleys  4  &amp;  6 , and Outer Driven Timing Belt  15 .  
         [0014]      FIG. 7 : The Apparatus according to  FIG. 7  displays all the characteristics of  FIG. 6  with one different application and one added feature. This said figure illustrates a different application, which constitutes of two Outer Driven Timing Belts  17  &amp;  18 . This said added feature constitutes of adding an inner flange to each of the two outer driven pulleys  4  and  6 .  
         [0015]      FIG. 8 : The Apparatus according to  FIG. 8  displays the two raw pulleys used in the manufacturing of the said Hybrid Pulley. This said Figure illustrates the raw Driven Source Pulley  19  and the raw Drive Source Pulley  20  respectively. This said  FIG. 8  displays the machining of the drive shaft bore and the key way throughout the entire width of these said raw pulleys. All items discussed in this said  FIG. 8  are described and shown on this said Figure.  
         [0016]      FIG. 9 : The Apparatus according to  FIG. 9  displays all the characteristics of  FIG. 8  with one added feature and one removed feature. The said added feature is the machining of three small bores which are used for alignment and attachment. Two of the said three bores are located at 110 degrees from each other. The third bore is located at 125 degrees from the first two. The said removed feature is the key way. Views XII and XV of this said Figure illustrate the raw Driven Source Pulley  21  and the raw Drive Source Pulley  22  respectively. Views XII and XIV display the machining of the drive shaft bore and the three said small bores throughout the entire width of these said raw pulleys  21  &amp;  22 . All items discussed in this said  FIG. 9  are described and shown on this said Figure.  
         [0017]      FIG. 10 : The Apparatus according to  FIG. 10  displays all the characteristics of  FIG. 8  with one added feature and one removed feature. The said added feature is the machining of three small bores which are used for alignment and attachment. Two of the said three bores are located at 110 degrees from each other. The third bore is located at 125 degrees from the first two. The said removed feature is the key way. Views XVII and XIX illustrate the raw Driven Source Pulley  24  and the raw Drive Source Pulley  25  respectively. Views XVI thru XVIII display the machining of the drive shaft bore and the three said small bores throughout the entire width of these said raw pulleys. On this said raw Driven Source Pulley  24 , the three said small bores are counter-sunk from one side of this said raw Driven Source Pulley  24 . All items discussed in this said  FIG. 10  are described and shown on this said Figure.  
         [0018]      FIG. 11 : The Apparatus displayed on  FIG. 11  shows the same characteristics of  FIG. 6  with respect to the Hybrid Pulley Assembly. However, on this said  FIG. 11 , a Drive Source Timing Pulley  26  is remotely located from the Hybrid Pulley Assembly. This said  FIG. 11  illustrates one of the possible configurations of applying this Hybrid Pulley Assembly in a belt driven system.  
         [0019]      FIG. 12 : The Apparatus displayed on  FIG. 12  shows the same characteristics of  FIG. 7  with respect to the Hybrid Pulley Assembly. However, on this said  FIG. 12 , a Drive Source Timing Pulley  26  is remotely located from the Hybrid Pulley Assembly. This said  FIG. 12  illustrates a second possible configuration for applying this Hybrid Pulley Assembly in a belt driven system. View XXI Illustrate the drive shaft  91  and the drive shaft key  92  in this said Hybrid Pulley Assembly.  
         [0020]      FIG. 13 : The Formula displayed on  FIG. 13  is used to calculate the Driven Pulley&#39;s diameter. 
     
    
     DETAILED DESCRIPTION  
       [0021]      FIG. 11  shows an example of a method for applying this Three Piece Timing Pulley Assembly in a drive train system. The Centerpiece-Timing Pulley  5  will only drive the Outer Driven Timing Pulleys  4  &amp;  6 . The Inner Drive Timing Belt  16 , which is connected to a Drive Source Pulley  26  that is driven by a motor shaft or a gear head, positively drives the Centerpiece-Timing Pulley  5 . The axial position of the timing teeth of the Driven Pulleys  4  &amp;  6  does not have to be synchronized with respect to the Drive Pulley  5  timing teeth. It is the fixed relative axial position between the Drive Pulley  5  teeth and the teeth of the Driven Pulleys  4  &amp;  6  that guarantees the positive drive and fixed relative timing between the Drive Pulley  5  and the Driven Timing Pulleys  4  &amp;  6 . The outer Driven Pulleys  4  &amp;  6  drive one Outer Driven Timing Belt  15 . The Outer Driven Timing Pulleys  4  &amp;  6  are equipped each with an outer Flange  27 .  
         [0022]      FIG. 1  illustrates the constructional sequence of this said Three Piece Timing Pulley Assembly. The two Outer-Timing Pulleys  1  &amp;  3  are the Driven Synchronized Pulleys and the Centerpiece-Timing Pulley  2  is the Drive Pulley. This Three Piece Timing Pulley Assembly may be referred to throughout the context of this document as Compound Pulley Assembly, a Hybrid Pulley Assembly, or a Synchronized Timing Pulley Assembly. The Outer Driven Timing Pulleys  1  &amp;  3  are equipped each with an outer Flange  27 .  
         [0023]     In  FIG. 1 , the Centerpiece-Timing Pulley  2  may be referred to throughout the context of this document as Drive Pulley, Driver Pulley, Inner Drive Pulley, or Inner Driver Timing Pulley.  
         [0024]     In  FIG. 6  with its respective cross sectional view VI for this said Hybrid Pulley Assembly, displays the Inner Driver Pulley  5  outside diameter D 2 . This outside diameter D 2  is limited by the Outer Driven Timing Pulley  6  outside diameter D 1 , less twice the tooth depth Z 1  of the Driven Timing Belt  15 , and less twice the belt thickness T 2  of the Driver Timing Belt  16 . The outside diameter D 2  of this said Inner Driver Timing Pulley  5  can be calculated using the formula displayed in  FIG. 13 .  
         [0025]     In  FIG. 6  with its respective cross sectional view XIX for this said Hybrid Pulley Assembly, it displays the application with one Outer Driven Timing Belt  15 . In this case, the width of this said Outer Driven Timing Belt  15  dictates the overall width of this said Hybrid Pulley Assembly. This said overall width is the sum of the width PW 1  of the first Outer Timing Pulley  4 , the width PW 2  of the Inner Driver Timing Pulley  5 , the width PW 3  of the second Outer Timing Pulley  6 , and a belt relief. Therefore, in most cases, the width of the Outer Driven Timing Belt  15  is less than the width of the Hybrid Pulley Assembly. For example, a T5 timing belt width is 5 mm less than that of a timing pulley width, which is a typical recommendation set by timing belt manufacturers.  
         [0026]     In  FIG. 6  with its respective cross sectional view VI for this said Hybrid Pulley Assembly, it displays the said Inner Drive Timing Belt  16 , the Outer Driven Timing Belt  15 , the Outer Driven Timing Pulleys  6 , and the Inner Driver Timing Pulley  5 . In this said view VI, the top surface of the Inner Drive Timing Belt  16  defines the Interface Drive Plane  100  and the bottom surface of the timing teeth of the Outer Driven Timing Belt  15  defines the Interface Driven Plane  200 .  
         [0027]     In  FIG. 6  with its respective cross sectional view XIX for this said Hybrid Pulley Assembly, it displays the said Inner Drive Timing Belt  16 , the Outer Driven Timing Belt  15 , the Outer Driven Timing Pulleys  4  &amp;  6 , the Inner Driver Timing Pulley  5 , the outer Flanges  27 , the Interface Drive Plane  100 , the Interface Driven Plane  200 , and the enclosed Hybrid Pulley Interface Gap  300 . In an ideal configuration, when the formula in  FIG. 13  is satisfied, this said Interface GAP  300  would equal to zero. However, if the Outer Diameter D 2  of the Inner Drive Pulley  5  calculated by the formula displayed in  FIG. 13  is not available, the next available lower Outer Diameter could be used with a constraint. This said constraint is the size of the said Hybrid Pulley Interface Gap  300  that is created between the said Interface Drive Plane  100  and the said Interface Driven Plane  200 . This said constraint must not exceed the maximum unsupported deflection value recommended by the manufacturer of the Outer Driven Timing Belt  15 . In addition, even if the Diameter D 2  of the Inner Driver Timing Pulley  5  satisfies the formula displayed in  FIG. 13 , the stack of tolerances for the Inner Driver Timing Pulley  5  diameter D 2 , the Inner Drive Timing Belt  16  thickness T 2 , and the Outer Driven Timing Pulleys  4  &amp;  6  diameter D 1  will create this said Interface Gap  300 . Typically, this stack of tolerance could total 0.020″, which leads to an Interface Gap  300  of 0.020″ that would be acceptable for most timing belts with steel reinforcement.  
         [0028]      FIG. 12  shows an example of another method of applying this Three Piece Timing Pulley Assembly in a drive train system. The Centerpiece-Timing Pulley  5  will only drive the outer Driven Timing Pulleys  4  &amp;  6 . The Inner Drive Timing Belt  16 , which is connected to a Drive Source Pulley  26  that is driven by a motor shaft or a gear head, positively drives the Centerpiece-Timing Pulley  5 . The axial position of the timing teeth of the Driven Pulleys  4  &amp;  6  does not have to be synchronized with respect to the Drive Pulley  5  timing teeth. It is the fixed relative axial position between the Drive Pulley  5  teeth and the teeth of the Driven Pulleys  4  &amp;  6  that guarantees the positive drive and fixed relative timing between the Drive Pulley  5  and Driven Timing Pulleys  4  &amp;  6 . The Outer Driven Timing Pulley  4  will drive an Outer Driven Timing Belt  18 , and the Outer Driven Timing Pulley  6  will drive an Outer Driven Timing Belt  17 . These two Outer Driven Timing Belts are synchronized.  
         [0029]     In  FIG. 7  with its respective cross sectional view VII for this said Hybrid Pulley Assembly displays the Inner Driver Pulley  5  outside diameter D 2 . This outside diameter D 2  is limited by the Outer Driven Timing Pulley  6  outside diameter D 1 , less twice the tooth depth Z 1  of the Driven Timing Belts  17  or  18 , and less twice the belt thickness T 2  of the Driver Timing Belt  16 . The outside diameter D 2  of this said Inner Driver Timing Pulley  5  can be calculated using the formula displayed in  FIG. 13 .  
         [0030]     In  FIG. 7  with its respective cross sectional view XX for this said Hybrid Pulley Assembly displays the application with Two Outer Driven Timing Belts  17  and  18 . In this case, the width of the Outer Timing Belt  17  dictates the width PW 3  of the Outer Timing Pulley  6 . The width of the Outer Timing Belt  18  dictates the width PW 1  of the Outer Timing Pulley  4 . The one additional feature that this said  FIG. 7  displays, which is not featured on  FIG. 6  for the single driven outer belt Hybrid Pulley Assembly, is the addition of the inner Flanges  27  to the inner sides of the Outer Driven Timing Pulleys  4  &amp;  6 .  
         [0031]     The following paragraph explains how to prepare for making either of the following Inner Driver Pulleys;  5  in  FIG. 2, 7  in  FIG. 3, 10  in  FIG. 4 , or  52  in  FIG. 5 .  
         [0032]     Obtain a timing pulley whose material (Aluminum, Steel, Nylon, etc.), tooth profile, and outside diameter D 2  is sized for the Driver Timing Belt  16 , which is selected by the designer or specified by its application. The Diameter of this said pulley D 2  will be obtained by the Formula in  FIG. 13 . This said Timing Pulley could be purchased as a stand-alone pulley whose width is PW 2  or as a timing pulley stock that will be cut to a width of PW 2 . This said Timing Pulley may be referred to throughout the context of this document as Driver Source Pulley.  
         [0033]     The following paragraphs explain how to make either of the Outer Driven Timing Pulley sets  4  &amp;  6 ,  8  &amp;  30 ,  9  &amp;  11 , or  50  &amp;  51 .  
         [0034]     Obtain a Timing Pulley whose material (Aluminum, Steel, Nylon, etc.), tooth profile, and outside diameter D 1  is sized for the Driven Timing Belt, which is selected by the designer or specified by its application. This said Timing Pulley could be purchased as a stand-alone pulley with outer Flanges  27  as depicted in  FIG. 8 ,  FIG. 9 , and  FIG. 10 , or as a timing pulley stock. This said Timing Pulley stock or this said stand-alone pulley may be referred to throughout the context of this document as Driven Source Pulley.  
         [0035]     The Driven Source Pulley width must be at a minimum the sum of PW 1 , PW 3 , belt relief, and the cutting gap requirement. This said cutting gap distance is dependant on the cutting method to be adopted. This said cutting gap requirement could be 0.250-inch minimum inclusive of the width of the cutting tool used.  
         [0036]     This said Driven Source Pulley must be cut to produce two pulleys whose widths are PW 1  &amp; PW 3 . However, prior to cutting this said Driven Source Pulley, the two pieces to be produced from this said Driven Source Pulley must be referenced for synchronization. Three methods for referencing and guaranteeing the synchronization are listed below. Other methods for synchronization can be used as long as they yield the same results obtained below.  
         [0037]     Synchronization Method One: In  FIG. 8 , if the said Driven Source Pulley  19  does not have a pilot bore, then drill a pilot bore. This said pilot bore diameter is dictated by the keyed shaft  91  diameter depicted in  FIG. 12 . A shaft key way must be machined from one end to another in this said Driven Source Pulley  19 . The size of the shaft key way is determined by the application and limited by the size of the Driver Source Pulley  20 . The said Driver Source Pulley  20  must have a pilot bore drilled and a shaft key way machined identical to that of the said Driven Source Pulley  19 .  
         [0038]     Synchronization Method Two: In  FIG. 9 , if the said Driven Source Pulley  21  does not have a pilot bore, then drill a pilot bore. This said pilot bore diameter is dictated by the drive shaft  90  diameter depicted in  FIG. 3 . Three pilot bores are drilled into this said Driven Source Pulley  21 . Two of the said three bores are located at 110 degrees from each other. The third bore is located at 125 degrees from the first two. The angular spacing selected here is a preference. Other Angular spacing could be used as long as the holes are not distributed symmetrically around the pulley axis. These holes could be located on a circle whose diameter is ⅔ of that of the outer diameter D 2  of the Driver Source Pulley  22 . In addition, the diameter of the three pilot holes could be ⅛″ (0.125″) but other sizes may be selected depending on the application. The said Driver Source Pulley  22  must have a pilot bore and three pilot holes drilled identical to that of the said Driven Source Pulley  21 .  
         [0039]     Synchronization Method Three: In  FIG. 10 , if the said Driven Source Pulley  24  does not have a pilot bore, then drill a pilot bore. This said pilot bore diameter is dictated by the drive shaft  90  diameter depicted in  FIG. 4  or by the Drive Shaft Bearings  12  outer diameter depicted in  FIG. 5 . Three pilot holes are drilled into this said Driven Source Pulley  24 . Two of the said three bores are located at 110 degrees from each other. The third bore is located at 125 degrees from the first two. The angular spacing selected here is a preference. Other Angular spacing could be used as long as the holes are not distributed symmetrically around the pulley axis. These holes could be located on a circle whose diameter is ⅔ of that of the outer diameter D 2  of the Driver Source Pulley  25 . The Tap Drill Size for the Mounting Screws  13  selected for this application determines the diameter of the said three pilot holes. For example, a ¼-20 UNC Machine Screw requires a pilot hole diameter of 0.201″ or drill #7. One side of this said Driven Source Pulley  24  would have the three pilot holes counter-sunk to burry the head of the said Mounting Screws  13 . See  FIG. 4  or  FIG. 5  for machine screw application. Then, on this said side, three pilot holes will be oversized to a diameter equal to the outer body diameter of the selected Machine Screws  13 . However, this secondary drilling operation will be at a controlled depth or distance equal to the width of the Outer Driven Pulleys  9  or  50  depicted in  FIG. 4  and  FIG. 5  respectively. The other side of this said Driven Source Pulley  24  would have the three pilot holes tapped to the selected thread size and overall thread length of the Outer Driven Pulleys  11  or  51  depicted in  FIG. 4  and  FIG. 5  respectively. The said Driver Source Pulley  25  must have a pilot bore drilled identical to that of the said Driven Source Pulley  24 . This said Driver Source Pulley  25  must have three pilot holes drilled identical in location to that of the said Driven Source Pulley  24 . However, the said three pilot holes&#39; diameter must be equal to that of the diameter of the said Machine Screw  13  outer body diameter.  
         [0040]      FIG. 2  shows this said Hybrid Pulley Assembly with a pilot bore and a key way design, which is one of the Synchronization Methods. The front cross-sectional view II of this said  FIG. 2  illustrates how the pilot bore and key way extend throughout the three pieces that constitute this Hybrid Pulley Assembly; the two Outer-Timing Pulleys  4  &amp;  6  and the Centerpiece Timing Pulley  5 . The Outer Driven Timing Pulleys  4  &amp;  6  are equipped each with an outer Flange  27 .  
         [0041]     The said Driven Source Pulleys  19  in  FIG. 8, 21  in  FIG. 9 , and  24  in  FIG. 10  will have two pieces cut from it to produce two timing pulleys whose widths are PW 1  &amp; PW 3  as depicted in  FIG. 6  or  FIG. 7 . EDM is the preferred method of cutting since it yields lower stress on the pulley&#39;s timing teeth, which minimizes tooth distortion. Other methods of cutting can be used as long as they do not distort any of the pulley&#39;s timing teeth.  
         [0042]      FIG. 12  shows the three pieces of the timing pulleys  4 ,  5  and  6  assembled into the said Hybrid Pulley Assembly using a drive shaft  91  and a key  92 . If the Driven Source Pulley  19  was obtained from a pulley stock, the outer Flanges  27  can now be drilled in order to be mounted onto the produced Outer Driven Timing Pulleys  4  &amp;  6  respectively. View XXI of this said  FIG. 12  provides further clarification on the location of this said Drive Shaft  91  and Key  92 . The Three Piece Hybrid Pulley assembly is now available for use.  
         [0043]      FIG. 4  shows the Three Piece Hybrid Pulley Assembly utilizing the Machine Screw method of synchronization. View IV of this said figure shows a sectional view of this said Hybrid Pulley Assembly, which comprises of Machine Screws  13 . The Outer Driven Timing Pulleys  9  &amp;  11  are equipped each with an outer Flange  27 .  
         [0044]      FIG. 5  shows the Three Piece Hybrid Pulley Assembly utilizing the Machine Screw method of synchronization. View V of this said figure shows a sectional view of this said Hybrid Pulley Assembly, which comprises of Machine Screws  13 , and Drive Shaft Bearings  12 . Additional attention has to be placed to the location of the mentioned Mounting Shaft Bearings  12  in the bore of each timing pulley. The Bearing position accomplishes the proper alignment of the Centerpiece-Timing Pulley  52  with respect to each of the Outer-Timing Pulleys  50  &amp;  51 . This is critical because there will be no timing belt or timing pulley binding resulting between the Drive Shaft  90  displayed in  FIG. 5  and the Mounting Shaft Bearings  12 . The Outer Driven Timing Pulleys  50  &amp;  52  are equipped each with an outer Flange  27 .  
         [0045]      FIG. 3  shows the Three Piece Hybrid Pulley Assembly utilizing the Dowel Pin method of synchronization. View III of this said figure shows a sectional view of this said Hybrid Pulley Assembly with the Dowel Pins  14  inserted through the three pieces of this said Hybrid Pulley Assembly. The Outer Driven Timing Pulleys  30  &amp;  8  are equipped each with an outer Flange  27 .