| JPH08514 | [Title of Invention] Automatic Clutch Control Device |
| WO/2004/044459 | A SHORT-STROKE LINEAR ELECTROMECHANICAL ACTUATOR |
| JPS58114926 | 【考案の名称】クラツチ操作装置 |
| WO2010001827A1 | 2010-01-07 |
| EP0222312A1 | 1987-05-20 | |||
| FR1531246A | 1968-06-28 | |||
| EP0209943A1 | 1987-01-28 | |||
| US3893191A | 1975-07-01 | |||
| GB878273A | 1961-09-27 | |||
| US3071226A | 1963-01-01 | |||
| US8851258B2 | 2014-10-07 | |||
| CN201916038U | 2011-08-03 | |||
| CN203463518U | 2014-03-05 | |||
| CN206903736U | 2018-01-19 | |||
| CN210686765U | 2020-06-05 | |||
| FR1071474A | 1954-09-01 | |||
| KR101664499B1 | 2016-10-10 | |||
| US20110036678A1 | 2011-02-17 |
| CLAIMS 1. Rotary motion control apparatus (10) including a housing (12) of an annular shape having a cylindrical outer surface (14) extending between first and second ends (16, 18) and an operational cavity, a rotor (46) rotationally received in the operational cavity, with the rotor (46) including a hub (48), an annular shaped friction facing (50) and a disk (52) extending between the friction facing (50) and the hub (48) and allowing flexible movement of the friction facing (50) relative to the hub (48), an actuation plate (60) of an annular shape, with the friction facing (50) being intermediate the actuation plate (60) and the housing (12), and springs (86) biasing the actuation plate (60) towards the friction facing (50), with the actuation plate (60) being moved against the bias of the springs (86); wherein the rotary motion control apparatus further comprises, in combination: a flexible plate (70) secured to the housing (12) and to the actuation plate (60) and moveably connecting the actuation plate (60) to the housing (12), with the flexible plate (70) having sufficient flexibility to allow the actuation plate (60) and the flexible plate (70) secured thereto to move axially away from the housing (12) to sandwich the friction facing (50) intermediate the housing (12) and the actuation plate (60) and relative to the housing (12) and the flexible plate (70) secured thereto. 2. The rotary motion control apparatus (10) of claim 1, wherein the housing (12) includes an output flange (34) of an annular shape having first and second spaced, parallel, planar surfaces, with the first end of the housing (12) abutting with the second surface of the output flange (34), with the friction facing (50) abutting with the second surface of the output flange (34), and with the fraction facing (50) being intermediate the actuation plate (60) and the second surface of the output flange (34). 3. The rotary motion control apparatus (10) of claim 2 further comprising, in combination: a plurality of bolts (36) extending axially through the housing (12) radially outward of the operational cavity; and threaded bores (38) axially extending from the second surface towards the first surface of the output flange (34), with the plurality of bolts (36) threadably received in the threaded bores (38). 4. The rotary motion control apparatus (10) of claim 2 or 3 further comprising, in combination: an electromagnet (90) located in the housing (12) on an opposite side of the actuation plate (60) than the output flange (34) and drawing the actuation plate (60) towards and against the bias of the springs (86). 5. The rotary motion control apparatus (10) of claim 4 further comprising, in combination: an annular cavity (26) axially extending in the housing (12) opposite to the output flange (34) and receiving the electromagnet (90). 6. The rotary motion control apparatus (10) of claim 5 further comprising, in combination: cylindrical cavities (28) axially extending in the housing (12) opposite to the output flange (34) and receiving the springs (86), with the cylindrical cavities (28) located in the housing (12) concentrically within and spaced from the annular cavity (26). 7. The rotary motion control apparatus (10) of claim 6 further comprising, in combination: first fasteners (76) extending towards the output flange (34) and through the flexible plate (70) and into the actuation plate (60), with the first fasteners (76) extending into the annular cavity (26); and second fasteners (80) extending away from the output flange (34) and through the flexible plate (70) and into the housing (12), with the second fasteners (80) located concentrically within the cylindrical cavities (28). 8. The rotary motion control apparatus (10) of claim 7, further comprising, in combination: bosses (32) extending in the housing (12) opposite to the output flange (34) and intersecting threaded cylindrical cavities (30) axially extending in the housing (12) opposite to the output flange (34), wherein the flexible plate (70) comprises an annular portion (72) for receipt in the annular cavity (26); and first tabs (74) extending radially inwardly of the annular portion (72), with the second fasteners (80) extending through the first tabs (74) and inside the bosses (32). 9. The rotary motion control apparatus (10) of claim 8, wherein the flexible plate (70) further comprises second tabs (78) extending radially outward of the annular portion (72), with the first fasteners (76) extending through the second tabs (78). 10. The rotary motion control apparatus (10) of claim 7, wherein the flexible plate (70) comprises an annular portion (72) for receipt in the annular cavity (26); and second tabs (78) extending radially outward of the annular portion (72), with the first fasteners (76) extending through the second tabs (78). 11. The rotary motion control apparatus (10) of any claim 7-10, further comprising, in combination: bores (62) extending through the actuation plate (60), with the second fasteners (80) extending away from the output flange (34) and through the bores (62). 12. The rotary motion control apparatus (10) of any preceding claim, wherein the disk (52) is of an axial thickness considerably less than the hub (48) and the friction facing (50). 13. The rotary motion control apparatus (10) of any preceding claim, wherein the hub (48) is adapted to be slideably fixedly received on a rotatable shaft. 14. The rotary motion control apparatus (10) of any preceding claim, wherein the housing (12) is adapted to be held stationary relative to ground. 15. Method comprising: positioning springs (86) in a housing (12); positioning an electromagnet (90) in the housing (12); extending first fasteners (76) through a flexible plate (70) and into an actuation plate (60); after extending the first fasteners (76) and positioning the springs (86) and the electromagnet (90), extending second fasteners (80) through the flexible plate (70) and into the housing (12); after extending the second fasteners (80), positioning a rotor (46) in an operational cavity in the housing (12); and after positioning the rotor (46), securing an output flange (34) to a first end of the housing (12). 16. The method of claim 15, wherein extending the second fasteners (80) comprises extending the second fasteners (80) through bores (62) of the actuation plate (60) and through the flexible plate (70) and into the housing (12). 17. The method of claim 15 or 16, wherein positioning the springs (86) comprises positioning the springs (86) in cylindrical cavities (28) extending axially in the housing (12), with the springs (86) biasing the actuation plate (60) towards the rotor (46); and wherein extending the second fasteners (80) comprises extending the second fasteners (80) through first tabs (78) extending outwardly of an annular portion (72) of the flexible plate (70) and located in bosses (32) formed in the housing (12) and intersecting with a threaded cylindrical cavity (30) extending axially into the housing (12). 18. The method of claim 17, wherein positioning the electromagnet (90) comprises positioning the electromagnet (90) in an annular cavity (26) extending axially in the housing (12), with the electromagnet (90) drawing the actuation plate (60) towards the electromagnet (90), and wherein extending the first fasteners (76) comprises extending the first fasteners (76) through second tabs (74) extending inwardly of the annular portion (72) of the flexible plate (70) and extending into the actuation plate (60), with the first fasteners (76) extending into the annular cavity (26) after positioning the second fasteners (80). 19. The method of claim 15 or 16, wherein positioning the electromagnet (90) comprises positioning the electromagnet (90) in an annular cavity (26) extending axially in the housing (12), with the electromagnet (90) drawing the actuation plate (60) towards the electromagnet (90), and wherein extending the first fasteners (76) comprises extending the first fasteners (76) through second tabs (74) extending inwardly of an annular portion (72) of the flexible plate (70) and extending into the actuation plate (60), with the first fasteners (76) extending into the annular cavity (26) after positioning the second fasteners (80). 20. The method of any claim 15-19, wherein positioning a rotor (46) comprises positioning the rotor (46) including an annular friction facing (50) and a disk (52) extending radially inwardly from the friction facing (50), with the disk (52) allowing flexible movement of the friction facing (50) relative to the actuation plate (60) and to the output flange (34). |
| AMENDED CLAIMS received by the International Bureau on 23 September 2022 (23.09.22) 1. Rotary motion control apparatus (10) including a housing (12) of an annular shape having a cylindrical outer surface (14) extending between first and second ends (16, 18) and an operational cavity, a rotor (46) rotationally received in the operational cavity, with the rotor (46) including a hub (48), an annular shaped friction facing (50) and a disk (52) extending between the friction facing (50) and the hub (48) and allowing flexible movement of the friction facing (50) relative to the hub (48), an actuation plate (60) of an annular shape, with the friction facing (50) being intermediate the actuation plate (60) and the housing (12), springs (86) biasing the actuation plate (60) towards the friction facing (50), with the actuation plate (60) being moved against the bias of the springs (86), and a flexible plate (70) secured to the housing (12) and to the actuation plate (60) and moveably connecting the actuation plate (60) to the housing (12), with the flexible plate (70) having sufficient flexibility to allow the actuation plate (60) and the flexible plate (70) secured thereto to move axially away from the housing (12) to sandwich to the friction facing (50) intermediate the housing (12) and the actuation plate (60) relative to the housing (12) and the flexible plate (70) secured thereto; characterized in that the housing (12) includes an output flange (34) of an annular shape having first and second spaced, parallel, planar surfaces, with the first end of the housing (12) abutting with the second surface of the output flange (34), with the friction facing (50) abutting with the second surface of the output flange (34), and with the fraction facing (50) being intermediate the actuation plate (60) and the second surface of the output flange (34). 2. The rotary motion control apparatus (10) of claim 1 further comprising, in combination: a plurality of bolts (36) extending axially through the housing (12) radially outward of the operational cavity; and threaded bores (38) axially extending from the second surface towards the first surface of the output flange (34), with the plurality of bolts (36) threadably received in the threaded bores (38). 3. The rotary motion control apparatus (10) of claim 1 or 2 further comprising, in combination: an electromagnet (90) located in the housing (12) on an opposite side of the actuation plate (60) than the output flange (34) and drawing the actuation plate (60) towards and against the bias of the springs (86). 4. The rotary motion control apparatus (10) of claim 3 further comprising, in combination: an annular cavity (26) axially extending in the housing (12) opposite to the output flange (34) and receiving the electromagnet (90). 5. The rotary motion control apparatus (10) of claim 4 further comprising, in combination: cylindrical cavities (28) axially extending in the housing (12) opposite to the output flange (34) and receiving the springs (86), with the cylindrical cavities (28) located in the housing (12) concentrically within and spaced from the annular cavity (26). 6. The rotary motion control apparatus (10) of claim 5 further comprising, in combination: first fasteners (76) extending towards the output flange (34) and through the flexible plate (70) and into the actuation plate (60), with the first fasteners (76) extending into the annular cavity (26); and second fasteners (80) extending away from the output flange (34) and through the flexible plate (70) and into the housing (12), with the second fasteners (80) located concentrically within the cylindrical cavities (28). 7. The rotary motion control apparatus (10) of claim 6, further comprising, in combination: bosses (32) extending in the housing (12) opposite to the output flange (34) and intersecting threaded cylindrical cavities (30) axially extending in the housing (12) opposite to the output flange (34), wherein the flexible plate (70) comprises an annular portion (72) for receipt in the annular cavity (26); and first tabs (74) extending radially inwardly of the annular portion (72), with the second fasteners (80) extending through the first tabs (74) and inside the bosses (32). 8. The rotary motion control apparatus (10) of claim 7, wherein the flexible plate (70) further comprises second tabs (78) extending radially outward of the annular portion (72), with the first fasteners (76) extending through the second tabs (78). 9. The rotary motion control apparatus (10) of claim 6, wherein the flexible plate (70) comprises an annular portion (72) for receipt in the annular cavity (26); and second tabs (78) extending radially outward of the annular portion (72), with the first fasteners (76) extending through the second tabs (78). 10. The rotary motion control apparatus (10) of any claim 6-9, further comprising, in combination: bores (62) extending through the actuation plate (60), with the second fasteners (80) extending away from the output flange (34) and through the bores (62). 11. The rotary motion control apparatus (10) of any preceding claim, wherein the disk (52) is of an axial thickness considerably less than the hub (48) and the friction facing (50). 12. The rotary motion control apparatus (10) of any preceding claim, wherein the hub (48) is adapted to be slideably fixedly received on a rotatable shaft. 13. The rotary motion control apparatus (10) of any preceding claim, wherein the housing (12) is adapted to be held stationary relative to ground. 14. Method comprising: positioning springs (86) in a housing (12) of an annular shape having a cylindrical outer surface (14) extending between first and second ends (16, 18) and an operational cavity; positioning an electromagnet (90) in the housing (12); extending first fasteners (76) through a flexible plate (70) and into an actuation plate (60) of an annular shape; after extending the first fasteners (76) and positioning the springs (86) and the electromagnet (90), extending second fasteners (80) through the flexible plate (70) and into the housing (12), with the flexible plate (70) secured to the housing (12) and to the actuation plate (60) and moveably connecting the actuation plate (60) to the housing (12), with the flexible plate (70) having sufficient flexibility to allow the actuation plate (60) and the flexible plate (70) secured thereto to move axially away from the housing (12) to sandwich to the friction facing (50) intermediate the housing (12) and the actuation plate (60) relative to the housing (12) and the flexible plate (70) secured thereto; after extending the second fasteners (80), positioning a rotor (46) in the operational cavity in the housing (12), wherein positioning a rotor (46) comprises positioning the rotor (46) including an annular friction facing (50) and a disk (52) extending radially inwardly from the friction facing (50), with the disk (52) allowing flexible movement of the friction facing (50) relative to the actuation plate (60) and to the output flange (34); and after positioning the rotor (46), securing an output flange (34) to a first end of the housing (12), with the output flange (34) of an annular shape having first and second spaced, parallel, planar surfaces, with the first end of the housing (12) abutting with the second surface of the output flange (34), with the friction facing (50) abutting with the second surface of the output flange (34), and with the fraction facing (50) being intermediate the actuation plate (60) and the second surface of the output flange (34). 15. The method of claim 14, wherein extending the second fasteners (80) comprises extending the second fasteners (80) through bores (62) of the actuation plate (60) and through the flexible plate (70) and into the housing (12). 16. The method of claim 14 or 15, wherein positioning the springs (86) comprises positioning the springs (86) in cylindrical cavities (28) extending axially in the housing (12), with the springs (86) biasing the actuation plate (60) towards the rotor (46); and wherein extending the second fasteners (80) comprises extending the second fasteners (80) through first tabs (78) extending outwardly of an annular portion (72) of the flexible plate (70) and located in bosses (32) formed in the housing (12) and intersecting with a threaded cylindrical cavity (30) extending axially into the housing (12). 17. The method of claim 16, wherein positioning the electromagnet (90) comprises positioning the electromagnet (90) in an annular cavity (26) extending axially in the housing (12), with the electromagnet (90) drawing the actuation plate (60) towards the electromagnet (90), and wherein extending the first fasteners (76) comprises extending the first fasteners (76) through second tabs (74) extending inwardly of the annular portion (72) of the flexible plate (70) and extending into the actuation plate (60), with the first fasteners (76) extending into the annular cavity (26) after positioning the second fasteners (80). 18. The method of claim 14 or 15, wherein positioning the electromagnet (90) comprises positioning the electromagnet (90) in an annular cavity (26) extending axially in the housing (12), with the electromagnet (90) drawing the actuation plate (60) towards the electromagnet (90), and wherein extending the first fasteners (76) comprises extending the first fasteners (76) through second tabs (74) extending inwardly of an annular portion (72) of the flexible plate (70) and extending into the actuation plate (60), with the first fasteners (76) extending into the annular cavity (26) after positioning the second fasteners (80). |
BACKGROUND
An apparatus for controlling rotary motion and its method of fabrication are shown and described providing zero-backlash.
Rotary brakes transfer torque from a rotatable shaft to a stationary housing and are applicable to, but not limited to commonly used actuation methods including electromagnetic, pneumatic, and hydraulic. In conventional rotary brakes, axial movement of internal components is used to capture or engage the rotatable rotor, which results in a mechanical connection between a stationary component and the components that translate axially. Common methods of mechanically connecting axially moveable components include splines, pins, studs and bushings, all of which require mechanical clearance to operate freely. Clearance leads to stiffness losses and torsional backlash which can result in undesirable motion of a locked axis in an application. Thus, a need exists for apparatus for controlling rotary motion resulting in zero-backlash.
GB 878,273 discloses a rotary motion control apparatus including a housing of an annular shape having a cylindrical outer surface extending between first and second ends and an operational cavity, a rotor rotationally received in the operational cavity, with the rotor including a hub, an annular shaped friction facing and a disk extending between the friction facing and the hub and allowing flexible movement of the friction facing relative to the hub, an actuation plate of an annular shape, with the actuation plate moveably connected to the housing by a shell slideable on studs, with the friction facing being intermediate the actuation plate and the housing, and springs biasing the actuation plate towards the friction facing to sandwich to the friction facing intermediate the housing and the actuation plate, with the actuation plate being moved against the bias of the springs.
Of further interest are Patent Nos. US3071226, US8851258, CN201916038U, CN203463518U, CN206903736U, CN210686765U, FR1071474 and KR101664499B1 and Publication Nos. W02010001827A1 and US 20110036678.
SUMMARY
This need and other needs in the field of rotary motion control are solved by providing a rotary motion control apparatus with zero-backlash. Specifically, a rotary motion control apparatus is provided with a flexible plate secured to the housing and to the actuation plate and moveably connecting the actuation plate to the housing. The flexible plate has sufficient flexibility to allow the actuation plate and the flexible plate secured thereto to move axially away from the housing to sandwich the friction facing intermediate the housing and the actuation plate and relative to the housing and the flexible plate secured thereto.
Additionally, the housing of the rotary motion control apparatus includes an output flange having the second of first and second spaced, parallel, planar surfaces abutting with the first end of the housing and abutting with the friction facing.
Further, the rotary motion control apparatus further includes an electromagnet located in the housing on a same side of the actuation plate as the springs and drawing the actuation plate towards and against the bias of the springs, with an annular cavity in the housing receiving the electromagnet. Cylindrical cavities in the housing receive the springs, with the cylindrical cavities located in the housing concentrically within and spaced from the annular cavity. First fasteners extend through the flexible plate and into the actuation plate, with the first fasteners extending into the annular cavity. Second fasteners extend through the flexible plate and into the housing, with the second fasteners located concentrically within the cylindrical cavities. Bores extend through the actuation plate, with the second fasteners extending through the bores.
Illustrative embodiments will become clearer in light of the following detailed description described in connection with the drawings.
DESCRIPTION OF THE DRAWINGS
The illustrative embodiments may best be described by reference to the accompanying drawings where:
Figure 1 shows an exploded perspective view of a rotary motion control apparatus with the actuation mechanism removed for ease of illustration.
Figure 2 shows a cross sectional view of the rotary motion control apparatus of Figure 1 including an actuation mechanism and in a disengaged position.
Figure 3 shows a cross sectional view of the rotary motion control apparatus of Figure 1 including an actuation mechanism and in an engaged position.
All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the figures with respect to number, position, relationship and dimensions of the parts to form the illustrative embodiments will be explained or will be within the skill of the art after the following description has been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following description has been read and understood.
Where used in the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms “top”, “bottom”, “first”, “second”, “forward”, “rearward”, “reverse”, “front”, “back”, “height”, “width”, “length” “end”, “side”, “horizontal”, “vertical”, and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the illustrative embodiments.
DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
Rotary motion control apparatus is shown in the drawings and generally designated 10. Apparatus 10 includes a housing 12 of an annular shape. In one manner of operation, housing 12 is held stationary relative to ground, such that apparatus 10 operates as a brake. Housing 12 has a cylindrical outer surface 14 extending between first and second ends 16 and 18. A cylindrical bore 20 axially extends between ends 16 and 18 and generally concentrically to surface 14. A cylindrical cavity defined by a cylindrical wall 22 axially extends from end 16 towards but spaced from second end 18 generally concentrically to and spaced inward from outer surface 14 and terminates in a radially extending wall 24. An annular cavity 26 extends axially from radially extending wall 24 towards but spaced from end 18 and concentrically to, intermediate and spaced from cylindrical bore 20 and outer surface 14. A plurality of cylindrical cavities 28 axially extend from radially extending wall 24 and are located concentrically within and spaced from annular cavity 26 and are located intermediate and spaced from annular cavity 26 and cylindrical bore 20. A plurality of threaded cylindrical cavities 30 axially extend from radially extending wall 24 and are located intermediate and spaced from annular cavity 26 and cylindrical bore 20 and are circumferentially intermediate plurality of cylindrical cavities 28. Each of threaded cylindrical cavities 30 include a relieved boss 32 formed in radially extending wall 24 and intersecting with annular cavity 26. Elongated bores 37 axially extend between ends 16 and 18 and intermediate and spaced from outer surface 14 and cylindrical wall 22 and annular cavity 26.
Housing 12 includes an output flange 34 of an annular shape having a diametric extent corresponding to outer surface 14. Output flange 34 has first and second spaced, parallel, planar surfaces. The second surface of output flange 34 abuts with first end 16 and is secured to housing 12 by a plurality of bolts 36 extending axially through elongated bores 37 and threadably engaged with threaded bores 38 formed in output flange 34. Output flange 34 includes a cylindrical bore 40 of a diametric size intermediate and spaced from central bore 20 and annular cavity 26. An operational cavity is defined between output flange 34 and radially extending wall 24 and having a minimum radial extent defined by cylindrical wall 22. Annular cavity 26, cylindrical cavities 28 and threaded cylindrical cavities 30 extend axially in housing 12 opposite to output flange 34.
Apparatus 10 also includes a rotor 46 received in the operational cavity. Rotor 46 includes a hub 48 such as for slidable fixed receipt on a rotatable shaft such as by way of a keyway as shown. Rotor 46 includes an annular shaped friction facing 50 having an inner radial extent 50a greater than cylindrical bore 40 and an outer radial extent 50b less than cylindrical wall 22 and abutting with the second surface of output flange 34. A disk 52 integrally extends between inner radial extent 50a and hub 48. Rotor 46 is formed as a single piece of homogenous material. Disk 52 is of an axial thickness considerably less than hub 48 and friction facing 50 to allow flexible movement of friction facing 50 relative to hub 48. However, rotor 46 can take other forms and types suitable for providing rotatable engagement and disengagement. As examples, rotor 46 can be of a design which minimizes or eliminates flexible movement. Similarly, different manners of engagement and disengagement of rotor 46 can be utilized such as, but not limited to, having toothed interfacing surfaces. In this regard, rotor 46 can be of any form or type allowing rotor 46 to be freely rotatable relative to housing 12 or to be rotatably fixed relative to housing 12.
Apparatus 10 further includes an actuation plate 60 of an annular shape. Friction facing 50 is intermediate actuation plate 60 and the second surface of output flange 34. Actuation plate 60 has an outer radial extent slightly less than and for moveable receipt in cylindrical wall 22. Actuation plate 60 has an inner radial extent generally coextensive with cylindrical bore 20 and greater than hub 48. A plurality of bores 62 extend through actuation plate 60 at circumferentially spaced locations corresponding to threaded cylindrical cavities 30. A plurality of threaded bores 64 extends through actuation plate 60 at circumferentially spaced locations corresponding to annular cavity 26. Apparatus 10 also includes a flexible plate 70 including an annular portion 72 of a size for receipt in annular cavity 26. Tabs 78 extend radially outwardly of annular portion 72. Fasteners 76 extend through tabs 78 towards output flange 34 and are threadably received in threaded bores 64 for securing flexible plate 70 to actuation plate 60. Tabs 74 extend radially inwardly of annular portion 72 and are received in relieved bosses 32. Fasteners 80 axially extend through tabs 74 away from output flange 34 and are threadably received in threaded cylindrical cavities 30 for securing flexible plate 70 to housing 12. Thus, actuation plate 60 is moveably connected to housing 12 by flexible plate 70.
Suitable provisions are provided for actuating apparatus 10 to move apparatus 10 between engaged and disengaged positions. As an illustrative embodiment, apparatus 10 includes a plurality of springs 86 located in cylindrical cavities 28 for biasing actuation plate 60 away from radially extending wall 24 and towards friction facing 50 to sandwich friction facing 50 intermediate output flange 34 of housing 12 and actuation plate 60. Apparatus 10 further includes a mechanism 90 for moving actuation plate 60 against the bias of springs 86 towards radially extending wall 24. In the illustrative embodiment shown, mechanism 90 is an electromagnet positioned within annular cavity 26 and suitably secured therein such as by adhesive. Mechanism 90 is located in housing 12 on an opposite side of actuation plate 60 than output flange 34 and draws actuation plate 60 towards and against the bias of springs 86. Particularly, actuation plate 60 is formed of magnetic material, such that when mechanism 90 is energized, actuation plate 60 is drawn towards and moves against the bias of springs 86 to abut with radially extending wall 24. Likewise, when mechanism 90 is not energized, actuation plate 60 is not drawn toward radially extending wall 24 and moves by the bias of springs 86 away from radially extending wall 24. It should be appreciated that flexible plate 70 has sufficient flexibility to allow actuation plate 60 and flexible plate 70 secured thereto by tabs 78 to move axially away from housing 12 to sandwich friction facing 50 intermediate output flange 34 of housing 12 under the bias of springs 86 and relative to housing 12 and flexible plate 70 secured thereto by tabs 74. It should be appreciated that mechanism 90 for moving actuation plate 60 can take other forms and types including, but not limited to, other forms and types of electromagnetic, pneumatic, hydraulic and/or manual actuation.
In assembling apparatus 10, fasteners 76 are extended into tabs 78 and threaded to bores 64 for securing flexible plate 70 to actuation plate 60. Springs 86 are positioned in cylindrical cavities 28. In the illustrative form shown, mechanism 90 is positioned in and suitably secured within annular cavity 26. Fasteners 80 are extended into tabs 74 and threaded into threaded cylindrical cavities 30 to secure flexible plate 70 and actuation plate 60 to housing 12 and sandwiching springs 86 between actuation plate 60 and the closed ends of cylindrical cavities 28. Rotor 46 is positioned in the cylindrical cavity defined by cylindrical wall 22. Output flange 34 is placed to abut first end 16 and housing 12, and bolts 36 are extended axially through bores 37 of housing 12 radially outward of the operational cavity and threaded into threaded cylindrical bores 38 extending axially from the second surface to the first surface of output flange 34.
In operation of the illustrative embodiment shown, when mechanism 90 is energized, actuation plate 60 is drawn against the bias of springs 86 to abut with radially extending wall 24. Thus, the axial spacing between actuation plate 60 and output flange 34 is greater than the axial thickness of friction facing 50. Thus, rotor 46 and the shaft rotatably fixed thereto are free to rotate relative to housing 12. When mechanism 90 is not energized, actuation plate 60 moves under the bias of springs 86 away from radially extending wall 24 to engage rotor 46 and sandwich friction facing 50 between output flange 34 and actuator plate 60, thereby rotatably fixing rotor 46 to housing 12. Assuming that housing 12 is rotatably fixed to ground, apparatus 10 functions as a brake to stop rotation of rotor 46 and the shaft received therein. As actuation plate 60 moves away from radially extending wall 24, rotor 46 is flexed to axially move friction facing 50 to contact with output flange 34 and actuation plate 60. Flexible plate 70 fastened to housing 12 by fasteners 80 and to actuation plate 60 by fasteners 76 is rotatably fixed to housing 12 but allows axial movement and actuation without the addition of backlash. Further, disengaging friction facing 50 from output flange 34 and actuator plate 60 occurs without an externally applied force to rotor 46, resulting in zero torsional drag on the rotatable shaft received in hub 48 of rotor 46.
Thus, since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.
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