Abstract
A cable and pulley or guide apparatus for accurately tuning and securing a tunable vibrating membrane on a cylindrical shell by means of a plurality of either fixed-angle pulley or guide assemblies not parallel to the top-bottom axis of the shell, or adjustable-angle pulley or guide assemblies not parallel to the top-bottom axis of the shell, built into or attached to purpose built hoops, attached to hoops with protruding flanges through holes or slots, or attached to a claw or hook apparatus which secures over the edge of annular hoops, through which a cable is laced and fed into the tensioning mechanism(s) to increase or decrease the tension on the cable, thus tensioning the vibrating membrane or heads against the shell, the angles of the pulley or guide assemblies adjustable to conform to the natural angle of the cable traversing the circumference of the shell.
Claims
1. A drum tension system for tuning a vibrating membrane on a drum shell, the drum tension system comprising: a mounting assembly adjacent to an exterior surface of the drum shell, the mounting assembly comprising: a bracket protruding from the exterior surface of the drum shell; a top attached to the bracket; a drive gear supported by the top, the drive gear defining an axis of rotation that is perpendicular to the drum shell; a driven gear interfaced with the drive gear, the driven gear defining an axis of rotation that intersects a central axis of the drum shell; and a winding post fixed to the driven gear and located between the top and the exterior surface of the drum shell, the winding post comprising: a cylindrical shaft, configured to spool a cable; and an adjustable handle fixed to the drive gear and rotatable relative to the mounting assembly whereby rotation of the adjustable handle changes tension of the vibrating membrane by either tightening or loosening the cable.
2. The drum tension system of claim 1 and further comprising: an opening formed in the bracket whereby the cable is disposed in the opening.
3. The drum tension system of claim 1 and further comprising: a planetary gear disposed between the adjustable handle and the drive gear.
4. The drum tension system of claim 1 wherein: the axis of rotation of the drive gear is perpendicular to the cable.
5. The drum tension system of claim 1 and further comprising: at least one fastener attaching the mounting assembly to the drum shell.
6. The drum tension system of claim 1 wherein the winding post further comprises: a receptacle formed in the cylindrical shaft and configured for engaging the cable along the cylindrical shaft.
7. The drum tension system of claim 6 wherein the winding post further comprises: at least one hole formed through the cylindrical shaft, configured to allow a non-crimped end of the cable to pass through the cylindrical shaft.
8. A drum tension system for tuning a vibrating membrane on a drum shell, the drum tension system comprising: a top hoop fitting the vibrating membrane on the drum shell; a plurality of top pulley assemblies adjoining the top hoop, wherein each of the top pulley assemblies comprises: a hoop pulley supported by each of the top pulley assemblies; and wherein the hoop pulley is angled relative to the drum shell; a plurality of brackets adjoining the drum shell, wherein each bracket comprises: a first bracket pulley supported by each of the brackets at an angle relative to the drum shell; a cable adjoining the hoop pulley of each of the top pulley assemblies and each of the first bracket pulley of the brackets, wherein the cable is parallel to each of the hoop pulley and the first bracket pulley; and a tensioning mechanism to adjust tension by either tightening or loosening the cable, thereby tuning the vibrating membrane.
9. The drum tension system of claim 8 wherein each of the plurality of brackets is attached to the drum shell.
10. The drum tension system of claim 8 and further comprising: a bottom hoop fitting a second vibrating membrane on the drum shell; a plurality of bottom pulley assemblies adjoining the bottom hoop, wherein each of the bottom pulley assemblies comprise: a bottom pulley supported by each of the bottom pulley assemblies at an angle relative to the drum shell; wherein each of the plurality of brackets further comprises: a second bracket pulley supported by the brackets at an angle relative to the drum shell; and wherein the cable is adjoining each pulley of the top pulley assemblies, the bottom pulley assemblies, the first bracket pulley, and the second bracket pulley.
11. The drum tension system of claim 8 wherein each of the brackets further comprises: a pulley axle about which the first bracket pulley rotates; wherein the vibrating membrane defines a vibrating membrane plane that is coplanar to the vibrating membrane; and wherein the pulley axle is oblique to the vibrating membrane plane.
12. The drum tension system of claim 11 wherein each of the brackets further comprises: a second axle adjustably attaching the first bracket pulley to the brackets, the second axle positioned tangent to the drum shell; and wherein the pulley axle and the first bracket pulley are movable relative to the vibrating membrane plane.
13. A drum tension system for tuning a vibrating membrane on a drum shell, the drum tensioning system comprising: a top hoop fitting the vibrating membrane on the drum shell; a plurality of pulley assemblies adjoining the top hoop; a cable running over the pulley assemblies, the cable comprising: a crimped end; and a non-crimped end; a tensioning mechanism to adjust tension by either tightening or loosening the cable, the tensioning mechanism comprising: a winding post comprising: a cylindrical shaft, configured to spool the cable; and a receptacle to accept the crimped end of the cable; and whereby rotation of the winding post changes tension of the vibrating membrane by either tightening or loosening the cable.
14. The drum tension system of claim 13 wherein the cylindrical shaft further comprises: holes to receive the non-crimped end of the cable.
15. The drum tension system of claim 13 wherein the cylindrical shaft further comprises: slot formed in the winding post, the slot passing through the winding post.
16. The drum tension system of claim 13 wherein the cylindrical shaft further comprises: a threaded hole formed in an end of the cylindrical shaft, configured to attach a gear.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 illustrates the overall layout of the basic variation of the invention from side (FIG. 1A) and overhead (FIG. 1B) views on a cylindrical shell, as well as the relation of the cable's natural angle to the shell as it traverses the circumference of the shell.
(2) FIG. 2 shows side views of the adjustable-angle pulley assembly, mounted to hoops with protruding flanges for the bolt-on version (FIG. 2A), and the claw version for annular hoops (FIG. 2B), and the relation of the pulley angle to the natural path of the cable as it traverses the circumference of the shell.
(3) FIG. 3 shows detailed views on hoops with protruding flanges bolt-on version of the adjustable-angle pulley assembly, including an exploded view (FIG. 3A) and dissected view (FIG. 3B).
(4) FIG. 4 shows detailed views of the annular hoop claw version of the adjustable-angle pulley assembly.
(5) FIG. 5 shows more detailed views of the claw version of the adjustable-angle pulley assembly.
(6) FIG. 6 shows detailed views of a possible tensioning mechanism and mounting bracket.
(7) FIG. 7 shows views of an adjustable-angle pulley assembly that can be manually set to a specific degree of angle.
(8) FIG. 8 shows views of a sheet metal version of the adjustable-angle pulley assembly.
(9) FIG. 9 shows views of a fixed-angle pulley assembly which directly correlates to the angle of the cable depending on the size of the corresponding shell.
(10) FIG. 10 shows prior art from U.S. Pat. No. 9,006,548 (Bedson FIG. 4), which illustrates that the cable is entering and exiting the pulley at a different angle than the pulley itself when the pulley is fixed parallel to the shell.
(11) FIG. 11 shows a planetary gear tensioning mechanism.
(12) FIG. 12 shows prior art of one embodiment of a drop-down detuner tensioning mechanism.
(13) FIG. 13 shows prior art of a standard tension rod and bracket tensioning system.
(14) FIG. 14 shows the incorporation of a tension or strain gauge mounted to the shell.
(15) FIG. 15 shows a configuration of the system applied to independently tunable top and bottom heads.
(16) FIG. 16 shows a configuration of angled pulley assemblies integrated into hoops.
(17) FIG. 17 shows a tensioning mechanism mounting bracket with integrated worm gear mechanism.
(18) FIG. 18 shows a winding post.
(19) FIG. 19 shows a side view of the invention with the adjustable-angle pulleys shown in FIG. 3 and the tensioning mechanism mounting bracket shown in FIG. 17.
DETAILED DESCRIPTION
(20) Within the invention there are two types of angled pulley (pulleys, guides or grommets 205) assemblies 106: fixed-angle (FIG. 9) and adjustable-angle (FIG. 1-5, 7, 8). A fixed angle pulley assembly (FIG. 9) is non-adjustable, in which the angle of the pulley housing 901 is fixed in direct relation to the natural angle of the cable (FIG. 1,2, 10) on that specific diameter and depth of shell 103. A fixed-angle pulley assembly can be a bolt-on fixture (FIG. 9) utilizing a ridge 902 or boss 903 to keep the fixture from rotating from its desired place on the hoop 102, or built into a claw fixture 402, or built into the hoop 102. An adjustable-angle pulley assembly (FIG. 1-5, 7, 8) can be a bolt-on fixture (FIG. 2A) also employing a ridge 216 or boss 903 to keep the fixture from rotating from its desired place on the hoop 102, or a claw fixture (FIG. 2B) employing a contact surface 512 where the use of velcro, tape, set screw, or any other form of attachment so that when there is no cable tension, the claw 501 stays in its' respective place on the hoop 401 and does not detach unintentionally. Both configurations consist of a pulley housing 206 either machined or cast (FIG. 2-5, 7) or bent or stamped sheet metal (FIG. 8) which is attached by one or more axles or rotation points 207 to a separate fixture 209/211 which attaches to the hoop 201. The adjustable-angle pulley assembly (FIG. 1-5, 7, 8) has the ability to adjust to different angles for different sized drums. An adjustable-angle pulley assembly can be free floating to adjust the angle itself under cable tension (FIG. 2-5, 8), or manually adjustable (FIG. 7) wherein an adjustment bolt 706 threaded into a piece 705 which lies within the bolt-on fixture 702 received by the pulley housing 701. When the bolt 706 is turned it pulls or pushes the top of the pulley housing 701 which is rotating on an axle 704 thus adjusting the angle of which the pulley housing 701 is in relation to the bolt-on fixture 702. The angle degree can be read by markings on the bolt-on fixture 708 and markings on the pulley housing 707.
(21) The use of non-perpendicular fixed-angle (FIG. 9) or adjustable-angle pulley assemblies (FIG. 1-5, 7, 8) allows the pulley 205 to follow the angle at which the cable 104 is laced between the top and bottom hoops 102 while traversing the circumference of the drum shell 103. Because the cable 104 is traversing the circumference of the drum shell 103 (FIG. 1), the angle of the cable 104 will never be directly parallel to the top-bottom axis of the shell 103 itself. The angle of the cable 104 varies depending on the number of pulley assemblies 106, and the diameter and depth of the shell 103. Therefore, the use of an angled pulley housing assembly is creating an environment of least friction and wear because it is allowing the pulley 205 to follow the cable's natural angle of least resistance 204, which angle also distributes the load from the cable tension evenly on the pulley 205 and its axle 207, rather than skewing the load to the outer edges of the pulley 205 and the axle 207. The adjustable-angle pulley assembly (FIG. 2) is enhanced by incorporating a control stop 314 which keeps the assembly from angling too far and making contact with the shell itself 103. See FIG. 3 314 (bolt-on assembly) and FIG. 5 506 (claw assembly).
(22) In order to tighten or loosen the cable tension, a tensioning mechanism, most obvious but not limited to; a reduction gear tensioning mechanism; exemplified as a planetary gear (FIG. 11) or worm gear (FIG. 6) can be built into the hoop 102, or attached to the shell 103 by a mounting bracket 612. The use of a planetary gear may or may not employ the need for a drive gear. In FIG. 6 the tensioning mechanism components 601-606 are attached to a mounting plate 608 by means of brackets 603 which hold the adjustment handle assembly 601/602/604 and a bolt 606 attaching the gear 605. The mounting plate 608 is bolted 607 onto the mounting bracket 612. The tensioning mechanism components 601-606 can also be built into the mounting bracket 612 itself to eliminate the need for a mounting plate 608, as described in FIG. 17. The cable 104 is threaded through a plurality of angled pulley assemblies 106, with one or both ends of the cable 104 passing through a slot 611 in the winding post 609, employing a receptacle 610 for one or both ends of the cable. When the adjustment handle 601 is turned, the axle 602 rotates, turning the threading 604 which correlates to the gear 605 which is bolted 606 to the winding post 609 thus spooling the cable 104. In FIG. 17, the worm gear or planetary gear components are integrated into the mounting bracket, eliminating the need for a mounting plate as described in FIG. 6/608. The drive gear with handle is supported by the top bracket 1703 which is bolted to the body 1704, thus trapping the drive gear 1702 in place while still allowing it to turn freely. The winding post 1705, which employs a slot for the cable to pass through 1806, a receptacle for ball or crimped end 1804, and 2 holes 1805 for a non-crimped end of the cable to pass through and cinch, the winding post passes through the mounting bracket and is attached to the main gear by a threaded hole in the top 1802 and a profile 1803 keeping the main gear from spinning freely from the winding post. The gearing reduction and frictional forces within the tensioning mechanism (FIG. 6, 11) allow for infinite non-incremental tuning control for both increasing and decreasing cable 104 and head 101 tension, as well as a separation of force between the winding post 609 and the point of adjustment 601. This mechanism (FIG. 6, 11) adjusts tension on the cable 104 smoothly and precisely in the direction of increasing and decreasing tension. The use of a reduction gear; planetary gear (FIG. 11) or worm gear (FIG. 6) reduces the amount of torque input or effort needed from the hand operated adjustment point 601, which allows the user to reach very high cable tension with little effort. This permits rapid and relatively effortless re-tuning of a drum that requires little force or user strength. The reduction mechanism (FIG. 6, 11) is free from ratcheting or pawl stops so that it can be tuned very precisely both directions, increasing or decreasing tension. The use of reduction gearing; worm gear (FIG. 6) or planetary gear tensioning mechanism (FIG. 11) also provides silent tuning which does not have an audible click that a ratchet or similar mechanism would have. There are many advantages to using a silent tensioning mechanism. Because there is no audible click, this allows the user to hear only the tone of the resonating drum while adjusting tension, which allows for the desired pitch to be recognized easier, as well as expanding the utility of the drum itself by allowing the pitch to be easily changed while playing the drum. A planetary gear (FIG. 11) or worm gear (FIG. 6) tensioning mechanism can be further enhanced by incorporating a ‘drop-down’ or ‘detuner’ tuning mechanism (FIG. 12), which allows for a quick drop or increase of tension. This allows for multiple predetermined tension settings to be easily reached on the fly.
(23) The utility of the invention can be enhanced (FIG. 14) by including an in-line tension gauge 1407 separate from the tensioning mechanism 1405, which facilitates accurate tuning so a specific desired pitch by bringing the cable 1404 to a pre-determined tension. The tension gauge can be built into a custom hoop 1402, integrated into the tensioning mechanism assembly 1405, free floating, or mounted to the shell 1403 (shown). Since drumhead pitch is a function of cable 1404 and head 1401 tension, the system allows accurate re-tuning even as the cable 1404 and head 1401 age and stretch, and even in noisy venues where re-tuning by listening to pitch may be impractical or where atmospheric variations make frequent re-tuning necessary.
(24) FIG. 1 shows a side view (FIG. 1A) and overhead view (FIG. 1B) of the present invention. 101 is the tunable vibrating membrane. 102 is the hoop with protruding flanges. 103 is the shell. 104 is the cable. 105 is the tensioning mechanism. 106 is the adjustable-angle pulley assembly.
(25) FIG. 2 shows the application of the bolt-on adjustable-angle pulley assembly for hoops with protruding flanges (FIG. 2A), the claw version of the adjustable-angle pulley assembly for annular hoops (FIG. 2B), and the relation of the natural angle of the cable in relation to the pulley itself as it is traversing the circumference of the shell. 201 is the hoop. 202 is the head. 203 is the shell. 204 is the cable. 205 is the pulley. 206 is the pulley housing. 207 is the axle which attaches the pulley housing to the bolt-on fixture. 208 is the axle which holds the pulley in place within the pulley housing. 209 is the bolt-on fixture which is bolted to the hoop with protruding flanges and the pulley housing. 210 is the bolt which attaches the hoop to the bolt-on fixture. 211 is the claw which takes the place of the bolt-on fixture for annular hoops.
(26) FIG. 3 shows different views of the adjustable-angle pulley assembly, including an exploded view (FIG. 3A) and dissected view (FIG. 3B). 301 is the bolt which attaches the bolt-on fixture to a hoop with protruding flanges. 302 is the axle which attaches the pulley housing to the bolt-on fixture, and allows the pulley housing angle to self-adjust. 303 is the axle which attaches the pulley to the pulley housing. 304 is the bolt-on fixture which connects to the pulley housing and the hoop with protruding flanges. 305 is the pulley. 306 is the pulley housing. 307 is an angled view of the bolt-on adjustable-angle pulley assembly. 308 is an angled view of the bolt-on adjustable-angle pulley assembly. 309 is a front facing view of the bolt-on adjustable-angle pulley assembly. 310 is a side view of the bolt-on adjustable-angle pulley assembly. 311 is a rear view of the bolt-on adjustable-angle pulley assembly. 312 is the hoop with protruding flanges. 313 is the drum head rim. 314 is the contact point of the control stop which keeps the pulley assembly from angling too far and making contact with the shell. 315 is the shell. 316 is the ridge to keep the fixture from rotating from its desired placement on the hoop.
(27) FIG. 4 shows the claw version of the adjustable-angle pulley assembly applied to an annular hoop. 401 is the hoop. 402 is the claw fixture. 403 is the pulley housing.
(28) FIG. 5 shows different views of the claw version of the adjustable-angle pulley assembly, including an exploded view. 501 is the claw fixture. 502 is the pulley housing. 503 is the pulley. 504 is the axle which attaches the pulley to the pulley housing. 505 is the axle which attaches the pulley housing to the claw fixture. 506 is the control stop which keeps the pulley housing from angling too far and making contact with the shell. 507 is an angled view of the claw version of the adjustable-angle pulley assembly. 508 is an angled view of the claw version of the adjustable-angle pulley assembly. 509 is a front facing view of the claw version of the adjustable-angle pulley assembly. 510 is a side view of the claw version of the adjustable-angle pulley assembly. 511 is a rear view of the claw version of the adjustable-angle pulley assembly. 512 is a contact surface where the use of velcro, tape, set screw, or any other form of attachment so that when there is no cable tension, the claw stays in its' respective place on the hoop and does not detach unintentionally.
(29) FIG. 6 shows detailed views of the tensioning mechanism and mounting bracket. 601 is the adjustment handle. 602 is the center axle of the worm gear adjustment. 603 is the bracket which keeps the adjustment handle in place. 604 is the threading which is part of the worm gear adjustment axle. 605 is the gear which is bolted through the mounting plate into the winding post. 606 is the bolt which attaches the gear to the winding post. 607 is the bolt which attaches the worm gear mounting plate to the mounting bracket. 608 is the worm gear mounting plate. 609 is the winding post. 610 is the receptacle which receives the ball or crimped end of the cable. 611 is the slot in the winding post which allows the cable to pass all the way through. 612 is the mounting bracket which connects the worm gear mounting plate to the shell. 613 is an angled view of the assembled worm gear tensioning mechanism. 614 is an overhead view of the assembled worm gear tensioning mechanism. 615 is a side view of the assembled worm gear tensioning mechanism. 616 is a front facing view of the assembled worm gear tensioning mechanism. 617 is a side view of the assembled worm gear tensioning mechanism.
(30) FIG. 7 shows detailed views of a bolt-on adjustable-angle pulley assembly with manual angle adjustment. 701 is the pulley housing. 702 is the bolt-on fixture. 703 is the guide, ridge or boss to center the fixture in the hole or slot of the hoop and keep the fixture from rotating from its desired placement on the hoop. 704 is the axle which attaches the pulley housing to the bolt-on fixture. 705 is a threaded piece which is received by a cutout in the bolt on fixture which allows the pulley housing angle to be adjusted when the bolt (706) is turned. 706 is the angle adjustment bolt. 707 is a marking of the angle in degrees. 708 is a marking on the bolt-on fixture which corresponds to markings on the pulley housing. 709 is an angled view of the bolt-on adjustable-angle pulley assembly with manual angle adjustment. 710 is a front facing view of the bolt-on adjustable-angle pulley assembly with manual angle adjustment. 711 is a side view of the bolt-on adjustable-angle pulley assembly with manual angle adjustment. 712 is a bottom view of the bolt-on adjustable-angle pulley assembly with manual angle adjustment. 713 is a rear view of the bolt-on adjustable-angle pulley assembly with manual angle adjustment. 714 is a section view of the bolt-on adjustable-angle pulley assembly with manual angle adjustment.
(31) FIG. 8 shows a version of the bolt-on adjustable-angle pulley assembly using a sheet metal version of the pulley housing. 801 is the bolt-on fixture as described in FIG. 2-209. 802 is the folded sheet metal pulley housing. 803 is the pulley. 804 is the axle which attaches the pulley housing to the bolt-on fixture. 805 is the axle which attaches the pulley to the pulley housing. 806 is the ridge which guides the pulley assembly to center the fixture in the hole or slot of the hoop and/or keep the fixture from rotating from its desired placement on the hoop as described in FIG. 7 (706). 807 is an overhead view of the adjustable-angle pulley assembly using a sheet metal version of the pulley housing. 808 is a front facing view of the adjustable-angle pulley assembly using a sheet metal version of the pulley housing. 809 is a side view of the adjustable-angle pulley assembly using a sheet metal version of the pulley housing. 810 is a rear view of the adjustable-angle pulley assembly using a sheet metal version of the pulley housing. 811 is a bottom view of the adjustable-angle pulley assembly using a sheet metal version of the pulley housing.
(32) FIG. 9 shows detailed views of a fixed-angle bolt-on pulley assembly in which the angle of the pulley is in direct relation to the natural path of the cable as it is traveling the circumference of the shell. 901 is the pulley housing. 902 is the ridge to keep the fixture from rotating from its desired placement on the hoop. 903 is the boss to center the fixture in the hole or slot of the hoop and point 465 where the fixture is bolted to the hoop. 904 is an angled view of the fixed-angle pulley assembly. 905 is an overhead view of the fixed-angle pulley assembly. 906 is a front facing view of the fixed-angle pulley assembly. 907 is a side view of the fixed-angle pulley assembly. 908 is a rear view of the fixed-angle pulley assembly. 909 is a bottom view of the fixed-angle pulley assembly.
(33) FIG. 10 shows prior art from U.S. Pat. No. 9,006,548 (Bedson FIG. 4), which illustrates that the cable is entering and exiting the pulley at a different 475 angle than the pulley itself when the pulley is fixed parallel to the shell.
(34) FIG. 11 shows a planetary gear tensioning mechanism. 1101 is the adjustment handle. 1102 is the mounting bracket. 1103 is the bolt attaching the mounting plate to the mounting bracket. 1104 is the threading which correlates to the planetary gear. 1105 is the planetary gear. 1106 is the planetary gear mounting plate.
(35) FIG. 12 shows prior art illustrating the components of a drop-down detuner tensioning mechanism.
(36) FIG. 13 shows prior art illustrating the standard tension rod and bracket tensioning system.
(37) FIG. 14 shows one possible configuration of a separate strain or tension gauge which measures how much tension is on the cable and therefore the head tension. 1401 is the head. 1402 is the hoop. 1403 is the shell. 1404 is the cable. 1405 is the tensioning mechanism. 1406 is the angled pulley assembly. 1407 is the strain or tension gauge.
(38) FIG. 15 shows a configuration of the system applied to independently tunable top and bottom vibrating membranes by incorporating a bracket attached to the shell which accepts an angled pulley assembly. 1501 is the bracket which accepts an angled pulley assembly.
(39) FIG. 16 shows a possible configuration where the angled pulley assembly is integrated into the hoop. 1601 is the hoop. 1602 is the bolt on fixture which is now integrated into the hoop which is the attachment point for the pulley housing. 1603 is the axle which attaches the pulley to the pulley housing. 1604 is the pulley housing. 1605 is the assembled pulley assembly on the integrated hoop. 1606 is the shell.
(40) FIG. 17 shows a mounting bracket assembly which integrates worm gear or planetary gear components, eliminating the need for a mounting plate. 1701 is the handle. 1702 is the drive gear connected to the handle. 1703 is the top bracket. 1704 is the bottom bracket/body. 1705 is the winding post. 1706 is a side view of the mounting bracket assembly. 1707 is a perspective view of the mounting bracket assembly. 1708 is an overhead view of the mounting bracket assembly.
(41) FIG. 18 is a winding post. 1801 is an overhead view of the winding post. 1802 is the threaded hole to attach the gear. 1803 is a profile cast or machined to fit into a corresponding slot in the gear. 1804 is a receptacle to accept a ball or crimped end of the cable. 1805 are holes to allow a non-crimped end of cable to pass through and cinch. 1806 is a slot which passes all the way through the winding post. 1807 is a side view of the winding post.
(42) FIG. 19 shows a side view of the invention with the adjustable-angle pulleys shown in FIG. 3 and the tensioning mechanism mounting bracket shown in FIG. 17. 1901 is the tunable vibrating membrane. 1902 is the hoop. 1903 is the adjustable-angle pulley assembly as shown in FIG. 3. 1904 is the cable. 1905 is the shell. 1906 is the mounting bracket assembly as shown in FIG. 17.
