ACTUATION

Priority

[0001] This application claims the benefit of priority of Indian provisional patent application Ser. No. 202111057511, filed December 10, 2021, the contents of which are incorporated herein by reference in their entirety.

Field

[0002] The subject application relates to, in general, a mechanism for unlatching a valve. More particularly, this application relates to an electromechanical actuation system for unlatching a valve to switch between a first lift profile and a second lift profile, e.g., a valve lift profile and a valve zero lift profile.

Background

[0003] Many internal combustion engines utilize oil gallery to control latching. However, such systems may have slow response time and high costs.

[0004] The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

Summary of the Invention

[0005] There is provided a switching roller finger follower assembly for use in an engine. The assembly including a bracket assembly including a first bracket and a second bracket that are pivotably connected to each other. The first bracket including a rotatable roller mounted thereto. The second bracket including a valve actuation surface configured to engage a distal end of a valve stem of a valve for moving the valve when the second bracket pivots. A latch pin assembly is provided on the second bracket for selectively locking the first bracket to a first position relative to the second bracket. [0006] In the assembly, the latch pin assembly is attached to the second bracket via a mounting pin.

[0007] In the assembly, the latch pin assembly includes a body provided with a hole extending therethrough. A latch pin is configured to slide axially within the hole between a first, locked position and a second, unlock position. The latch pin engages the first bracket when the first bracket is in the first position and the latch pin is in the first, locked position and the first bracket is freely pivotable relative to the second bracket when the latch pin is in the second, unlocked position. A spring biases the latch pin to one of the first, locked position or the second, unlocked position.

[0008] In the assembly, the latch pin includes a flat or groove configured to engage a pin provided in a body of the latch pin assembly, the pin positioned to hinder rotation of the latch pin relative to the body.

[0009] In the assembly, the pin extends through the second bracket.

[00010] In the assembly, the second bracket includes spaced-apart first and second legs and the second bracket is positioned between the first and the second legs.

[00011] In the assembly at least one spring biases the first bracket to the first position relative to the second bracket.

[00012] In the assembly, the first bracket pivots relative to the second bracket about a first axis and at least one spring is provided on an axis offset from the first axis for biasing the first bracket to the first position relative to the second bracket.

[00013] In the assembly, a lever is pivotably mounted to the second bracket. The lever has a distal end configured to engage a distal end of a latch pin of the latch pin assembly for selectively moving the latch pin.

[00014] In the assembly, the valve actuation surface is formed integral with the second bracket.

[00015] In the assembly, the valve actuation surface is pivotably mounted to the second bracket.

[00016] Further, there is provided an actuation system includes an actuator for moving an actuator lever between a first position and a second position. At least one switching roller finger follower assembly is engageable with the actuator lever. The assembly includes a bracket assembly including a first bracket and a second bracket that are pivotably connected to each other. The first bracket includes a rotatable roller mounted thereto. The second bracket includes a valve actuation surface configured to engage a distal end of a valve stem of a valve for moving the valve when the second bracket pivots. A latch pin assembly provided on the second bracket for locking the first bracket to a first position relative to the second bracket. The latch pin assembly engageable with the actuator lever wherein the actuator lever selectively moves a latch pin of the latch pin assembly to at least one of a first, locked position or a second, unlocked position.

[00017] In the actuation system, the latch pin assembly is attached to the second bracket via a mounting pin.

[00018] In the actuation system, the latch pin assembly including a body provided with a hole extending therethrough. A latch pin is configured to slide axially within the hole between a first, locked position and a second, unlock position. The latch pin engages the first bracket when the first bracket is in the first position and the latch pin is in the first, locked position and the first bracket is freely pivotable relative to the second bracket when the latch pin is in the second, unlocked position. A spring is provided for biasing the latch pin to one of the first, locked position or the second, unlocked position.

[00019] In the actuation system, the latch pin includes a flat or groove configured to engage a pin provided in a body of the latch pin assembly. The pin is positioned to hinder rotation of the latch pin relative to the body.

[00020] In the actuation system, the pin extends through the second bracket.

[00021] In the actuation system, the second bracket includes spaced-apart first and second legs and the second bracket is positioned between the first and the second legs.

[00022] In the actuation system, further including at least one spring for biasing the first bracket to the first position relative to the second bracket.

[00023] In the actuation system, the first bracket pivots relative to the second bracket about a first axis and at least one spring is provided on an axis offset from the first axis for biasing the first bracket to the first position relative to the second bracket.

[00024] In the actuation system, the latch pin assembly further includes a mounted lever pivotable relative to the second bracket. The mounted lever having a first end configured to engage a distal end of a latch pin of the latch pin assembly for selectively moving the latch pin and a second end configured to engage the actuator lever. [00025] In the actuation system, further including a plurality of switching roller finger follower assemblies provided in a first bank and a second bank and a connecting rod connected to the first bank and the second bank for simultaneously actuating the first bank and the second bank.

[00026] In the actuation system, the connecting rod moves in a linear direction that is orthogonal to at least one of the first bank and the second bank.

[00027] In the actuation system, the valve actuation surface is formed integral with the second bracket.

[00028] In the actuation system, the valve actuation surface is pivotably mounted to the second bracket.

Brief Description of the Drawings

[00029] FIG. 1 is a perspective view of an actuation assembly;

[00030] FIG. 2 is an end view of the actuation assembly of FIG. 1;

[00031 ] FIG. 3 is an enlarged view of an actuation lever of the actuation assembly;

[00032] FIG. 4A is a top perspective view of a switching roller finger follower (SRFF) assembly of FIG. 1 ;

[00033] FIG. 4B is a bottom perspective view of the SRFF assembly of FIG. 4A;

[00034] FIG. 5A is a top perspective view of an outer bracket of the SRFF assembly of

FIG. 4A;

[00035] FIG. 5B is a bottom perspective view of the outer bracket of FIG. 5A;

[00036] FIG. 6 is a perspective view of an inner bracket of the SRFF assembly of FIG.

4A;

[00037] FIG. 7 is a perspective view of a spring of the SRFF assembly of FIG. 4A;

[00038] FIG. 8 is a perspective view of a roller of the SRFF assembly of FIG. 4A

[00039] FIG. 9 is a perspective view of a latch pin assembly of the SRFF assembly of

FIG. 4A;

[00040] FIG. 10A is a sectional view taken along line 10- 10 of FIG. 9 with a latch pin in a first position;

[00041] FIG. 10B is a sectional view taken along line 10-10 of FIG. 9 with a latch pin in a second position; [00042] FIG. 11 is an exploded view of a portion of the SRFF assembly;

[00043] FIG. 12 is an exploded view of a portion of the SRFF assembly;

[00044] FIG. 13 is a sectional view taken along line 13-13 of FIG. 4A with a latch pin and inner bracket in a first position;

[00045] FIG. 14 is a sectional view taken along line 13-13 of FIG. 4A with a latch pin and inner bracket in a second position;

[00046] FIG. 15 A is a top perspective view of another embodiment of a switching roller finger follower (SRFF) assembly;

[00047] FIG. 15B is a bottom perspective of the SRFF assembly of FIG. 15 A;

[00048] FIG. 16A is a top perspective view of an outer bracket of the SRFF assembly of FIG. 15 A;

[00049] FIG. 16B is a bottom perspective view of the outer bracket of FIG. 15 A;

[00050] FIG. 17 is a perspective view of an inner bracket of the SRFF assembly of FIG.

14A;

[00051] FIG. 18 is a perspective view of a spring of the SRFF assembly of FIG. 15 A;

[00052] FIG. 19 is a perspective view of a latch pin assembly of the SRFF assembly of

FIG. 15 A;

[00053] FIG. 20A is a sectional view taken along line 19-19 of FIG. 19 with a latch pin in a first position;

[00054] FIG. 20B is a sectional view taken along line 19-19 of FIG. 19 with a latch pin in a second position;

[00055] FIG. 21 is a perspective view of a valve actuation block of the SRFF assembly of FIG. 15 A;

[00056] FIG 22A is a rear perspective view of a bushing of the SRFF assembly of FIG. 15 A;

[00057] FIG. 22B is a front perspective view of the bushing of FIG. 22A;

[00058] FIG. 23 is an exploded view of a portion of the SRFF assembly;

[00059] FIG. 24 is an exploded view of a portion of the SRFF assembly;

[00060] FIG. 25 is a sectional view taken along line 13-13 of FIG. 4A with a latch pin and inner bracket in a first position; [00061] FIG. 26 is a perspective view of yet another embodiment of a switching roller finger follower (SRFF) assembly;

[00062] FIG. 27 is a sectional view taken along line 27-27 of FIG. 26;

[00063] FIG. 28 is a top perspective view of still another embodiment of a switching roller finger follower (SRFF) assembly; and

[00064] FIG. 29 is a sectional view taken along line 29-29 of FIG. 28.

Detailed Description

[00065] The following presents a description of the disclosure; however, aspects may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Furthermore, the following examples may be provided alone or in combination with one or any combination of the examples discussed herein. Directional references such as “left” and “right” are for ease of reference to the figures.

[00066] Referring to FIGS. 1 and 2, the actuation system 50 includes an actuator 52 that is configured to move a connecting rod 54 in a straight path, as represented by arrow A in FIG. 2. It is contemplated that the actuator 52 may be configured for rotary movement or linear movement so long as the actuator 52 imparts lateral movement to the connecting rod 54.

[00067] The connecting rod 54 includes an elongated body 56 that is attached to the actuator 52. A pair of grippers 58 are provided on distal ends of the body 56. The grippers 58 are configured to engage levers 62 of the actuation system 50 to impart rotation (see arrows B) to them when the connecting rod 54 is actuated by the actuator 52.

[00068] Referring to FIG. 3, the lever 62 is attached to a control rod 64. Support brackets 66 are disposed at spaced-apart locations to provide support for the control rod 64 and to allow it to rotate when the lever 62 rotates. Fingers 68 are disposed at spaced-apart locations along control rod 64 to engage compliance levers 72.

[00069] Each compliance lever 72 includes an actuator leg 73 and two mounting legs 74 that attach the compliance lever 72 to the control rod 64. The compliance levers 72 are rotatably attached to the control rod 64. A coiled spring 76 is positioned on the control rod 64 at a location between the two legs 74 of the compliance lever 72. One leg 76a of the coiled spring 76 presses against the finger 68 and the other leg 76b presses against the compliance lever 72. The coiled spring 76 is configured to press the compliance lever 72 against the finger 68. Further, the coiled spring 76 is configured to transfer rotational force from the finger 68 to the compliance lever 72 so the compliance lever 72 and the control rod 64 may rotate as a common unit.

[00070] If the movement of the compliance lever 72 is prevented, e.g., by an obstruction, then the rotation of the finger 68 (via the control rod 64) will impart torsional force to the coiled spring 76 so that finger 68 may still move relative to the compliance lever 72 but the compliance lever 72 will remain stationary. When the compliance lever 72 is no longer prevented from moving, e.g., the obstruction is removed, then the torsional force of the coiled spring 76 will cause the compliance lever 72 to pivot until it contacts the finger 68 again.

[00071] Referring back to FIG. 1, the actuation system 50 includes a plurality of switching roller finger follower (SRFF) assemblies 100, in particular, a first bank 100A of SRFF assemblies and a second bank 100B of SRF assemblies 100. The first and second banks 100 A, 100B are positioned adjacent a cam rail 90 A, 90B, respectively. The cam rails 90A, 90B are provided with cam surfaces for engaging a roller 180 (FIG. 4A). As the cam rails 90 A, 90B rotate, the cam surfaces selectively impart movement to valves 80A, 80B (partially illustrated in FIG. 2) via engagement of the SRFF assemblies 100 with distal ends of respective valve stems 82a, 82b of the valves 80A, 80B. Each SRFF assembly 100 is positioned adjacent one compliance lever 72 such that movement of the compliance lever 72 actuates the corresponding SRFF assembly 100, as described in detail below.

[00072] Referring to FIGS. 4A-4B, each SRFF assembly 100 includes an outer bracket 110, an inner bracket 140, a lost motion spring 170, the roller 180, and a latch pin assembly 200.

[00073] Referring to FIGS. 5 A and 5B, the outer bracket 110 is a U-shaped element having opposing legs 112a, 112b and a base 114 from which the legs 112a, 112b extend. A bridge 116 extends between the legs 112a, 112b near their distal ends and defines a valve actuation surface 118 that is configured to engage the distal end of the valve stem 82a, 82b of the valve 80A, 80B (FIG. 2). The valve actuation surface 118 is formed integral with the outer bracket 110. A notch 114a is formed in one side of the base 114 and is positioned and dimensioned as described in detail below.

[00074] The legs 112a, 112b include a first pair of axially-aligned holes 122a, 122b and a second pair of axially-aligned holes 124a, 124b, respectively. The first pair of axially-aligned holes 122a, 122b define an axis along which a spring-support rod 126 (FIGS. 4A and 4B) is located. The second pair of axially-aligned holes 124a, 124b define an axis along which a pivot-support rod 128 (FIGS. 5A and 5B) is located.

[00075] A pair of kidney-shaped openings 132a, 132b are formed in the legs 112a, 112b between the second pair of holes 124a, 124b and the base 114. The openings 132a, 132b are dimensioned to allow a bearing-support rod 138 to translate therein, as described in detail below. A third pair of axially aligned holes 133a, 133b are formed in the opposing legs 112a, 112b proximate where the opposing legs 112a, 112b attach to the base 114. A pair of tabs 134a, 134b extend from an upper edge of the legs 112a, 112b from the side opposite the base 114. A pair of axially aligned holes 136a, 136b extend through a distal end of the tabs 134a, 134b.

[00076] Referring to FIG. 6, the inner bracket 140 is a U-shaped component having opposing legs 142a, 142b and a base portion 144. The legs 142a, 142b include a first pair of axially-aligned holes 152a, 152b, a second pair of axially-aligned holes 154a, 154b and a third pair of axially aligned holes 156a, 156b. The first pair of axially-aligned holes 152a, 152b are positioned and dimensioned to receive a stop 162. The second pair of axially-aligned holes 154a, 154b are positioned and dimensioned to receive the pivot-support rod 128 (FIGS. 4A and 4B). The third pair of axially-aligned holes 156a, 156b are positioned and dimensioned to receive the bearing-support rod 138 (FIGS. 4A and 4B).

[00077] The lost motion spring 170 is attached to the inner bracket 140 via the springsupport rod 126 (FIGS. 4A and 4B). Referring to FIG. 7, the spring 170 includes a coiled portion 172, a first leg 174 and a second leg 176. In the embodiment illustrated, the spring 170 is a torsional spring that is configured to apply a force via the first leg 174 and the second leg 176.

[00078] The roller 180 is dimensioned to rotate on the bearing-support rod 138 (FIGS. 4A and 4B). Referring to FIG. 8, the roller 180 includes a cylindrical-shaped body 182 with a plurality of bearings 184 disposed therein. The bearings 184 are configured to engage the bearing-support rod 128 (FIGS. 4A and 4B) to allow the roller 180 to rotate thereon.

[00079] The latch pin assembly 200 is mounted to the base 114 of the outer bracket 110 via fasteners 202 (FIGS. 4A and 4B). Referring to FIGS. 9-10B, the latch pin assembly 200 includes a body 204 having an elongated hole 206 provided therein for a latch pin 208 to laterally move between a first position (FIG. 10A) and a second position (FIG. 10B). [00080] The latch pin 208 is a rod-shaped element having a locking tab 212 at one distal end. A notch 214 is formed in a side of the latch pin 208 to receive a pin 216. It is contemplated that the notch 214 and the pin 216 are configured to prevent the latch pin 208 from rotating relative to the body 204.

[00081] A peripheral groove 218 is provided in an opposite end of the latch pin 208 to receive a snap ring 222. The body 204 includes a port 224 for allowing a fluid, e.g., oil, to be provided to an outer surface of the latch pin 208 to aid in the lateral movement of the latch pin 208 in the hole 206.

[00082] A biasing spring 226 is disposed around the latch pin 208 and is compressed between a ring 228 on the latch pin 208 and a cap 232 of the latch pin assembly 200. The biasing spring 226 is configured to bias the latch pin 208 to the first position (FIG. 10A).

[00083] A lever 242 is pivotably attached to the outer bracket 110 via a pin 244 (FIG. 4A and 4B). The lever 242 includes a first end 242a that is configured to engage the actuator leg 73 of the compliance lever 72 and a second end 242b that is configured to engage the latch pin 208. In the embodiment illustrated the second end 242b is fork-shaped and is dimensioned and contoured to engage a ring 246 positioned on the latch pin 208. In particular, the lever 242 is configured to apply a force to the latch pin 208, via the ring 246 when the lever 242 pivots about the pin 244 from a first position (FIG. 10A) to a second position (FIG. 10B).

[00084] A lower surface of the body 204 is contoured to define a pivot surface 252 for the SRFF assembly 100, as described in detail below.

[00085] Referring to FIG. 11, the latch pin assembly 200 is positioned on the base 114 and secured there via fasteners 202 (FIG. 4B). When positioned on the base 114, the pivot surface 252 in the body 204 of the latch pin assembly 200 aligns with the notch 114a in the base 114 (FIG. 4B). An upper surface of the body 204 includes notches 204a that are dimensioned and positioned to align with fingers 113 provided on an upper portion of the opposing legs 112a, 112b when the latch pin assembly 200 is positioned on the base 114.

[00086] Once positioned on the base 114, the pin 216 is inserted into hole 133a, through a hole 204b in the body 204 and through hole 133b. As noted above, the pin 216 is configured to be received into the notch 214 formed in the latch pin 208 to limit the movement of latch pin 208, as described in detail below. [00087] Pins 262a, 262b are inserted into respective grooves 139a, 139b in opposing leg 112a, 112b and into a mating holes 204c in the body 204. Further, the pin 244 is inserted into hole 136a, through pivot holes 242c of the lever 242 and into the hole 136b in the tab 134b. The pin 244 defines a pivot axis for the lever 242.

[00088] Referring to FIG. 12, the stop 162 is inserted into the hole 152a, 152b of the inner bracket 140. The inner bracket 140 is pivotable attached to the outer bracket 110 via the pivot-support rod 128 that extends through the hole 124a in the outer bracket 110, the holes 154a, 154b of the inner bracket 140 and the hole 124b in the outer bracket 110. The pivotsupport rod 128 defines a pivot axis of the inner bracket 140. With the inner bracket 140 positioned in the outer bracket 110, the bearing-support rod 138 is inserted through the curved opening 132a in the outer bracket 110, through the hole 156a of the inner bracket 140, through the roller 180, through the hole 156b of the inner bracket 140 and through the opening 132b in the outer bracket 110. The roller 180 is configured to rotate relative to the bearing-support rod 138 via the bearings 184. As the inner bracket 140 pivots relative to the outer bracket 110, distal ends of the bearings-support rod 138 translate within the pair of curved openings 132a, 132b in the outer bracket 110.

[00089] The spring 170 is positioned in the outer bracket 110 between the opposing legs 112a, 112b. In particular, the coiled portion 172 of the spring 170 aligns with the first pair of axially aligned holes 122a, 122b so the spring-support rod 126 may extend through the first pair of axially aligned holes 122a, 122b and the coiled portion 172 of the spring 170. The first leg 174 is positioned in engagement with the bridge 116 (FIG. 5B) and the second leg 176 is positioned in engagement with the notch 162a in the stop 162. The spring 170 is configured to apply a biasing force to the stop 162 to bias the inner bracket 140 to the first position, see FIG. 13.

[00090] Referring to FIG. 13, when the inner bracket 140 and the latch pin 208 are in the first position, rotation of the inner bracket 140 relative to the outer bracket 110 is prevented such that the application of a force to an upper surface of the roller 180 (see arrow C), e.g., via the cam rail 90 A, 90B(FIG. 2), causes the SRFF assembly 100 to pivot about the pivot surface 252. This pivoting causes a force (see arrow D) to be applied to the distal end of the valve stem 82a, 82b of the valve 80A, 80B that has a distal end engaging the bridge 116. [00091] Referring to FIG. 14, when the latch pin 208 is moved to the second position (see arrow E), e.g., through the actuation of the compliance lever 72 (FIG. 3) against the lever 242, the latch pin 208 allows the inner bracket 140 to pivot (see arrow F) against the biasing force of the spring 170 to the second position when a force is applied to the upper surface of the roller 180 (see arrow G), e.g., via the cam rail 90A, 90B (FIG. 2). It is contemplated that the pivoting movement of the inner bracket 140 is limited by the maximum distance that the bearing-support rod 138 may translate in the curve openings 132a, 132b in the outer bracket 110. Once the force applied to the roller 180 is removed, the biasing force from the spring 170 will pivot the inner bracket 140 back to the first position, as illustrated in FIG 13. In this position, the latch pin 208 is free to translate back to the first position via the biasing spring 226 once the force from the compliance lever 72 (FIG. 3) to the lever 242 is removed.

[00092] When the inner bracket 140 pivots relative to the outer bracket 110, the biasing force from the spring 170 also applies a force to the outer bracket 110. This force assists with maintaining the outer bracket 110 in contact with the distal end of the valve stem 82a, 82b (FIG. 2) to avoid the outer bracket 110 from flying off from the valve stem 82a, 82b (FIG. 2). [00093 ] It is contemplated that the lateral movement of the latch pin 208 within the body

204 may be limited by the dimensions of the notch 214 and the pin 216. The larger the notch 214, the further the pin 216 may allow the latch pin 208 to move when actuated.

[00094] According to another embodiment, illustrated in FIGS. 15A - 25, a SRFF assembly 300 is provided. The SRFF assembly 300 is similar to the SRFF assembly 100 described above. Similar components will be identified with similar reference numbers as used in the embodiment above. For brevity, a detailed description of each component will not be given.

[00095] The SRFF assembly 300 includes an outer bracket 310, an inner bracket 340, two lost motion springs 370A, 370B, the roller 180, and a latch pin assembly 400.

[00096] Referring to FIGS. 16A and 16B, the outer bracket 310 is a U-shaped element having opposing legs 312a, 312b and a base 314 from which the legs 312a, 312b extend. A notch 314a is formed in one side of the base 314 and is positioned and dimensioned as described in detail below. [00097] The legs 312a, 312b include a first pair of axially-aligned holes 322a, 322b. The first pair of axially-aligned holes 322a, 322b define an axis to which a spring-support and pivot rod 326 (FIGS. 15A and 15B) is attached.

[00098] A pair of kidney-shaped openings 332a, 332b are formed in the legs 312a, 312b between the first pair of holes 322a, 322b and the base 314. The openings 332a, 332b are dimensioned to allow a bearing-support rod 338 to translate therein, as described in detail below. A second pair of axially aligned holes 333a, 333b are formed in the opposing legs 312a, 312b proximate where the opposing legs 312a, 312b attach to the base 314.

[00099] A pair of inwardly extending fingers 313 are positioned along an upper edge of the opposing legs 312a, 312b proximate where the legs 312a, 312b attached to the base 314. Grooves 339a, 339b (groove 339b is partially obstructed in FIG. 16A) are formed in the upper edge of the opposing legs 312a, 312b adjacent the fingers 313. A pair of outwardly extending fingers 316 are positioned along the upper edge of the opposing legs 312a, 312b between the first pair of holes 322a, 322b and the openings 332a, 332b. In the embodiment illustrated, the fingers 313, 316 have a rectangular cross section. It is contemplated that the fingers 313, 316 may have other cross sectional shapes, including but not limited to, circular, square, etc.

[000100] Referring to FIG. 17, the inner bracket 340 is a U-shaped component having opposing legs 342a, 342b and a base portion 344. The legs 342a, 342b include a first pair of axially-aligned holes 352a, 352b, a second pair of axially-aligned holes 354a, 354b and a third pair of axially-aligned holes 356a, 356b. The first pair of axially-aligned holes 352a, 352b are positioned and dimensioned to receive the spring-support and pivot rod 326 (FIGS. 15A and 15B). The second pair of axially-aligned holes 354a, 354b are positioned and dimensioned to receive a rod 357. The third pair of axially-aligned holes 356a, 356b are positioned and dimensioned to receive the bearing-support rod 338 (FIGS. 15A and 15B).

[000101] A pair of outwardly extending feet 362 extend from a lower edge of the opposing leg 342a, 342b below the first pair of axially-aligned holes 352a, 352b. A notch 364 is formed in each of the feet 362. In the embodiment illustrated, the feet 362 have a rectangular cross section. It is contemplated that the feet 362 may have other cross sectional shapes, including but not limited to, circular, square, etc.

[000102] The first and second lost motion springs 370A, 370B are attached to the inner bracket 340 via the spring-support and pivot rod 126 (FIGS. 15A and 15B). Referring to FIG. 18, the first spring 370A is described in detail. The description of the second spring 370B is similar to the first spring 370B and is not provided for brevity. The first spring 370A includes a coiled portion 372, a first leg 374 and a second leg 376. In the embodiment illustrated, the first spring 370A is a torsional spring that is configured to apply a force via the first leg 374 and the second leg 376.

[000103] The roller 180 is dimensioned to rotate on the bearing-support rod 338 (FIGS. 15A and 15B). The roller 180 is described in detail above. For brevity, the description of roller 180 is not repeated.

[000104] The latch pin assembly 400 is mounted to the base 314 of the outer bracket 310 via fasteners 302 (FIGS. 15B). Referring to FIGS. 19-20B, the latch pin assembly 400 includes a body 404 having an elongated hole 406 provided therein for a latch pin 408 to laterally move between a first position (FIG. 20A) and a second position (FIG. 20B). A hole 404a extends through the body 404 for receiving a pin 416 (FIGS. 15A and 15B), as described in detail below. A hole 404c extends into opposite sides of the body 404. Only one hole 404c is visible in FIGS.19-20B.

[000105] The latch pin 408 is a rod-shaped element having a locking tab 412 at one distal end. A notch 414 is formed in a side of the latch pin 408 to receive a pin 416. A peripheral groove 418 is provided in an opposite end of the latch pin 408 to receive a snap ring 422. The body 404 includes a port 424 for allowing a fluid, e.g., oil, to be provided to an outer surface of the latch pin 408 to aid in the lateral movement of the latch pin 408 in the hole 406.

[000106] A biasing spring 426 is disposed around the latch pin 408 and is compressed between a ring 428 on the latch pin 408 and the body 404 of the latch pin assembly 400. The biasing spring 426 is configured to bias the latch pin 408 to the first position (FIG. 20A). A distal end of the latch pin 408 is configured to engage the actuator leg 73 of the compliance lever 72 (FIGS 2 and 3). The actuator leg 73 is configured to apply a force to the distal end of the latch pin 408 to move the latch pin 408 from the first position (FIG. 20A) to the second position (FIG. 20B).

[000107] A lower surface of the body 404 is contoured to define a pivot surface 452 for the SRFF assembly 300, as described in detail below.

[000108] Referring to FIGS. 15A and 15B, a valve actuation block 460 is positioned between opposing legs 342a, 342b of inner bracket 340. Referring to FIG. 21, the block 460 includes an upper surface having an elongated arcuate slot 462 formed in an upper surface of the block 460. The arcuate slot 462 is configured to be peripherally secured around a portion of the spring-support and pivot rod 326 such that the spring-support and pivot rod 326 may rotate within the arcuate slot 462 while the block 460 is retained to the rod 326. A lower surface of the block 460 defines a valve actuation surface 464 of the valve actuation block 460. The valve actuation surface 464 is configured to engage the distal end of the valve stem 82a, 82b of the valves 80A, 80B (FIG. 2). The valve actuation block 460 is configured to be a rocking valve pad that is suspended from the spring-support and pivot rod 326.

[000109] Referring to FIGS. 15A and 15B, two bushings 470A, 470B (only bushing 470A is visible in FIGS. 15A and 15B) are positioned adjacent an outer surface of the opposing legs 312a, 312b of the outer bracket 310. Referring to FIGS. 22A and 22B, the bushing 470A is described in detail. The description of the bushing 470B is similar to the bushing 470B and is not provided for brevity. The bushing 470A includes a body portion 472 with a contoured inner wall 474 and a contoured outer wall 476. The inner wall 474 is contoured to defined a plurality of curved surfaces that define bearing surfaces of the bushing 470A. The inner wall 474 is positioned to engage the outer wall of the spring-support and pivot rod 326. The outer wall 476 is contoured to define a plurality of spaced-apart raised surfaces. The outer wall 476 is positioned to engage an inner opening of the coiled portion 372 of the respective spring 370A. An outwardly extending flange 478 extends from a portion of a periphery of one end of the bushing 470A. It is contemplated that the flange 478 may extend from an entirety of the periphery of the bushing 470A so long as it does not obstruct the operation of the SRFF assembly 300 or any adjacent components.

[000110] Referring to FIG. 23, the latch pin assembly 400 is positioned on the base 314 and secured there via fasteners 302 (FIG. 15B). When positioned on the base 314, the pivot surface 452 in the body 404 of the latch pin assembly 400 aligns with the notch 314a in the base 314 (FIG. 15B). The body 404 is dimensioned to be positioned under fingers 313 provided on an upper portion of the opposing legs 312a, 312b when the latch pin assembly 400 is positioned on the base 314.

[000111] Once positioned on the base 314, the pin 416 is inserted into opening 332a, through a hole 404b in the body 404 and through opening 332b. As noted above, the pin 416 is configured to be received into the notch 414 formed in the latch pin 408 (FIGS. 20 A and 20B) to limit the movement of latch pin 408, as described in detail below.

[000112] Pins 462a, 462b are inserted into respective grooves 339a, 339b (FIG. 16A) in opposing legs 312a, 312b and into mating holes 404c in the body 404. Only one hole 404c is visible in FIG. 21.

[000113] Referring to FIG. 24, the rod 357 is inserted into the hole 352a, 352b of the inner bracket 340. The inner bracket 340 is pivotable attached to the outer bracket 310 via the spring-support and pivot rod 326 that extends through the bushing 470A, the spring 370A, the hole 322a in the outer bracket 310, the hole 352a of the inner bracket 340, the arcuate slot 462 of the valve actuation block 460, the hole 352b of the inner block, the hole 322b of the outer bracket 310, the spring 370B and the bushing 470B. The spring-support and pivot rod 326 defines a pivot axis of the inner bracket 340 and a support rod for the springs 370A, 370B.

[000114] The springs 370A, 370B are positioned such that the first leg 374 engages the finger 316 of the outer bracket 310 and the second leg 376 engages the notch 364 in the foot 362. The springs 370A, 370B are configured to apply a biasing force to the inner bracket 340 to bias the inner bracket 340 to rotate in the counter-clockwise, when viewed from the first leg 342a of the inner bracket 340.

[000115] With the inner bracket 340 positioned in the outer bracket 310, the bearingsupport rod 338 is inserted through the curved opening 332a in the outer bracket 310, through the hole 356a of the inner bracket 340, through the roller 180, through the hole 356b of the inner bracket 340 and through the opening 332b in the outer bracket 310. The roller 180 is configured to rotate relative to the bearing-support rod 338 via the bearings 184. As the inner bracket 340 pivots relative to the outer bracket 340, distal ends of the bearings-support rod 338 translate within the pair of curved openings 332a, 332b in the outer bracket 310.

[000116] Referring to FIG. 25, when the inner bracket 340 and the latch pin 408 are in the first position, the inner bracket 340 may freely pivot relative to the outer bracket 310 when a force (see arrow H) is applied to the roller 180 (e.g., via the cam rail 90A, 90B (FIG. 2)). The application of the force to the roller 180 causes the inner bracket 340 to pivot about the springsupport and pivot rod 326 (see arrow I) against the biasing forces of the springs 370A, 370B. It is contemplated that the pivoting movement of the inner bracket 340 is limited by the maximum distance that the bearing-support rod 338 may translate in the curve openings 332a, 332b in the outer bracket 310. Once the force applied to the roller 180 is removed, the biasing force from the springs 370A, 370B will pivot the inner bracket 340 back to the first position, as illustrated in FIG 25.

[000117] Similar to the latch pin 208 described in detail above, the latch pin 408 may move to another position (not shown) wherein the locking tab 412 of the latch pin 408 is positioned below the base portion 344 of the inner bracket 340. In this position, the latch pin 408 prevents the rotation of the inner bracket 340 when a force is applied to the roller 180. The rotation of the inner bracket 340 is prevented such that the application of a force to an upper surface of the roller 180, e.g., via the cam rail 90 A, 90B, causes the SRFF assembly 300 to pivot about the pivot surface 452. This pivoting causes a force to be applied to the valve stem 82a, 82b (FIG. 2) that has a distal end engaging the valve actuation block 460.

[000118] It is contemplated that the lateral movement of the latch pin 408 within the body 404 may be limited by the dimensions of the notch 414 and the pin 416. The larger the notch 414, the further the pin 416 may allow the latch pin 408 to move when actuated.

[000119] In the first embodiment described above, the SRFF assembly 100 includes a latch pin assembly 200 that is normally (i.e., when not acted upon) in an activated state such that the application of a force to the roller results in pivoting of the outer bracket 110 and the inner bracket 140 as a common unit. The latch pin 208 is actuated by pulling on the latch pin 208. Further, the SRFF assembly 100 includes a single spring.

[000120] In the second embodiment described above, the SRFF assembly 300 includes a latch pin assembly 400 that is normally (i.e., when not acted upon) in a deactivated state such that the application of a force to the roller 180 results in pivoting of the inner bracket 340 relative to the outer bracket 310. The latch pin 408 is actuated by pushing on the latch pin 408. Further, the SRFF assembly 100 includes two springs.

[000121] In an alternative embodiment (SRFF assembly 500), illustrated in FIGS. 26 and 27, the latch pin assembly 200 of the SRFF assembly 100 is replaced by the latch pin assembly 400. As described above, the latch pin assembly 400 is normally (i.e., when not acted upon) in a deactivated state such that the application of a force to the roller 180 results in pivoting of the inner bracket 140 relative to the outer bracket 110. The application of the latch pin assembly 200 does not require the lever 242 or the associated tabs 134a, 134b on the outer bracket 110. [000122] In yet another embodiment (SRFF assembly 700), illustrated in FIGS. 28 and 29, the latch pin assembly 400 of the SRFF assembly 300 is replaced by the latch pin assembly 200. As described above, the latch pin assembly 200 is normally (i.e., when not acted upon) in an activated state such that the application of a force to the roller 180 results in pivoting of the outer bracket 110 and the inner bracket 140 as a common unit. The application of the latch pin assembly 200 requires the addition of the associated tabs 134a, 134b to support the lever 242 needed to actuate the latch pin 208.

[000123] It is contemplated that the various inner and outer brackets may be made via cold forming and machining.

[000124] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the claimed invention.