Ratchet protection device

Abstract

A tooth jump protection device for controlling chain slack, delaying the torque at which chain jump occurs, thereby improving chain jump torque performance. The tooth jump protection device is preferably mounted to a transfer case.

Description

[0001] Cross-references to related applications

[0002] This application claims protection for one or more inventions disclosed in Provisional Application No. 63 / 140,448, filed January 22, 2021, entitled "TOOTH JUMP PROTECTION DEVICE," and Provisional Application No. 63 / 218,129, filed July 2, 2021, entitled "TOOTH JUMP PROTECTION DEVICE." The benefit of these Provisional Applications is claimed under 35 USC § 119(e), and both applications are incorporated herein by reference. Technical Field

[0003] This invention relates to chain slack buildup, and more particularly to a device for controlling the position of chain slack buildup. Background Technology

[0004] Figure 1a and 1b The approximate locations of slack accumulation relative to the driven sprocket 6 and drive sprocket 2 of a conventional chain system 1 are shown. Drive sprocket 2 is connected to driven sprocket 6 via a toothed chain 8. Chain 8 meshes with sprockets 2 and 6, transmitting rotational motion between them. Chain 8 may skip on either driven sprocket 6 or drive sprocket 2 in chain system 1. Skipping near driven sprocket 6 results in lower skipping torque, while skipping near drive sprocket 2 results in higher skipping torque. Therefore, forcing skipping only to occur on drive sprocket 2 improves the chain's skipping torque performance. The specific location of chain slack accumulation relative to either driven sprocket 6 or drive sprocket 2 identifies the sprocket on which chain 8 is most likely to skip. Figure 1a The relaxation accumulation occurring at the driven sprocket 6 is shown by reference numeral 30 in the attached figure. Figure 1b The relaxation accumulation occurring at drive sprocket 2 is shown, indicated by reference numeral 32. Summary of the Invention

[0005] According to one embodiment of the present invention, a skip protection device is used to control chain slack and delay the torque that causes chain skipping, thereby improving skip torque performance. Attached Figure Description

[0006] Figure 1a This diagram illustrates the approximate position of slack accumulation relative to the driven sprocket in a conventional chain system.

[0007] Figure 1b This diagram illustrates the approximate position of slack accumulation relative to the drive sprocket in a conventional chain system.

[0008] Figure 2 A schematic diagram of a vertically mounted transmission system is shown.

[0009] Figure 3 A schematic diagram showing an embodiment of a tooth skip protection device (TJPD) is provided.

[0010] Figure 4 A schematic diagram showing another embodiment of TJPD is shown.

[0011] Figure 5 Show Figure 4 A detailed view of the TJPD.

[0012] Figure 6 A cross-sectional view of the TJPD, which serves as a fixed-position conforming roller within the transfer case, is shown.

[0013] Figure 7 A detailed view of a TJPD with compliant rollers is shown.

[0014] Figure 8a A schematic diagram of a tilting buffer that engages with a chain inside the transfer case is shown.

[0015] Figure 8b A schematic diagram of the tilting buffer TJPD is shown when tension is applied to the opposing strands of the chain.

[0016] Figure 9 shows a prior art buffer that engages with a chain.

[0017] Figure 10 Another embodiment of TJPD is shown.

[0018] Figure 11a A schematic diagram shows a buffer placed at a specific distance relative to the driven sprocket and at a specific gap relative to the chain.

[0019] Figure 11b Showing relative to Figure 11a The slack accumulation of the buffer.

[0020] Figure 12 A view of a TJPD with a buffer installed in the transfer case is shown.

[0021] Figure 13 A schematic diagram of a compliant roller TJPD is shown, which is spring-biased to engage with a chain. Detailed Implementation

[0022] In one embodiment of the invention, a toothed runout protection device (TJPD) can be used to control chain slack within the transfer case, causing chain slack to accumulate only on the drive sprocket, resulting in higher runout torque. This higher runout torque capability allows for a reduction in chain width.

[0023] exist Figure 2 In the system layout, drive shafts 103 and 104, associated with drive shaft 2 and driven shaft 6 respectively, are shown in a vertical orientation, with driven sprocket 6 at the bottom and drive sprocket 2 at the top within the transfer case 107. A chain 8 connects drive sprocket 2 to driven sprocket 6. Between drive sprocket 2 and driven sprocket 8, the chain has slack strands 8b and tight strands 8a. When the transfer case is near the vertical orientation, gravity causes slack to accumulate at the junction between driven sprocket 6 and chain 8 within the transfer case 107. The study of tooth skipping and chain slack in this system layout was conducted using a rigid guide or tooth skipping protection device (TJPD) 120 placed at the entrance of the slack strands 8b, which engage with driven sprocket 6 at various radial offsets. The study determined that the TJPD device 120 preferably needs to be positioned radially away from the center of the sprocket to avoid interfering with the natural engagement of the chain and sprocket. This positioning increases with chain wear. The distance will vary depending on the system layout, chain design, and chain lifespan.

[0024] The TJPD 120 preferably provides sufficient load to keep chain 8 engaged with driven sprocket 6, with a load sufficient based on stiffness requirements. The stiffness requirements of the TJPD 120 depend on the applied peak torque, the radial offset of the TJPD 120, and the chain type and design. As the applied torque increases, the load required from the TJPD 120 to maintain proper engagement also increases. As chain 8 moves radially outward and deflects the TJPD 120, the force required from the TJPD 120 to maintain engagement with the driven sprocket increases. In terms of chain type and design, chain links with steeper side pressure angles will require less force from the TJPD 120. It is worth noting that the TJPD 120 must be flexible enough to withstand catastrophic drive sprocket bounce when chain 8 is about to wedge between driven sprocket 6 and the TJPD 120.

[0025] Figure 2 The transfer case is shown in a vertical position, but the system can be oriented at any angle in the application. TJPD 120 is located at the entrance of the driven sprocket 6. More specifically, TJPD 120 is located at the position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 first engages with the slack strand 8b of the chain 8 (e.g., when the chain 8 enters the entrance of the driven sprocket 6).

[0026] In one embodiment, one-piece fixed positions TJPD 130a, 130b are placed at the driven sprocket 6. Regardless of the transfer case azimuth angle, TJPD 130a, 130b are located at the inlet and / or outlet of the driven sprocket 6. More specifically, TJPD 130a is located at the position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 first engages with the slack chain strand 8b of the chain 8 (e.g., when the chain 8 enters the inlet of the driven sprocket 6), and TJPD 130b is located at the position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 last engages with the tight chain strand 8a of the chain (e.g., when the chain 8 leaves the outlet of the driven sprocket 6).

[0027] The integrated fixed-position TJPDs 130a and 130b have a body 131 made of plastic, steel, or aluminum, and a flat chain surface 132 that interacts with a chain 8, which may include an elastomeric coating. The integrated fixed-position TJPDs 130a and 130b can be buffers bolted to a transfer case 107 relative to the chain 8 and the driven sprocket 6. The thickness of the elastomeric coating can vary based on the chain and design layout. Furthermore, the thickness of the body 131 and / or the elastomeric coating on opposite sides of the driven sprocket 6 of the TJPDs 130a and 130b can be the same or different.

[0028] Figure 4-5 Another embodiment of the TJPD 175, mounted to the transfer case 107 and adjacent to the chain 8 and driven sprocket 6, is shown. In this embodiment, the TJPD 175 is an L-shaped, one-piece multifaceted ramp 140 with a mounting bracket 141. The mounting bracket 141 may be integrally formed with the multifaceted ramp 140. In one embodiment, the mounting bracket 141 and the one-piece multifaceted ramp 140 are formed from a single piece of steel. The mounting bracket 141 forms approximately a 90-degree angle with respect to the first flat surface 142 of the multifaceted ramp 140. In other words, the mounting bracket is the vertical portion of the L, and the multifaceted ramp 140 is the horizontal portion of the L. The multifaceted ramp 140 is preferably flexible and has a smooth profile.

[0029] The multi-faceted ramp 140 includes a first flat surface 142 at approximately 90 degrees to the mounting bracket 141, a first transition ramp 143, an inclined ramp 144, a second transition ramp 145, and a second flat surface 146. The second flat surface 146 has a face 146a that, when installed, is offset from the chain 8 by a small gap 147. As the chain 8 wears or stretches, the gap 147 decreases, and contact between the chain 8 and the face 146a is possible during normal operation of the chain 8. When the chain 8 rotates and skips teeth, the face 146a of the second flat surface 146 applies a reaction force to the chain 8 to maintain engagement of the chain 8 with the driven sprocket 6 and to prevent chain slack buildup on the driven sprocket 6.

[0030] Alternatively, the multifaceted ramp 140 may include offset flat planes with cantilevered sections between them. More specifically, the multifaceted ramp 140 may include a first flat plane 142, a second flat plane 146, and an inclined ramp 144, without transition ramps 143, 145. The inclined ramp 144 is preferably flexible and has a smooth profile.

[0031] Surface 146a may comprise a plastic or elastomer surface to minimize noise, vibration, and harshness (NVH) issues and improve the abrasion resistance of TJPD 140. Regardless of the transfer case azimuth angle, TJPD 140 is preferably mounted such that surface 146a of the second flat surface 146 is diametrically positioned at the driven sprocket 6 and / or drive sprocket 2 and at the inlet and / or outlet of the driven sprocket 6 or drive sprocket 2. More specifically, at least the first TJPD 140 is located at a position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 first engages with the slack strand 8b of the chain 8 (e.g., at the inlet of the driven sprocket 6). The second TJPD 140 may be located at a position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 last engages with the tight strand 8a of the chain (e.g., at the outlet of the driven sprocket 6).

[0032] Alternatively, TJPD 140 may include, for example, Figure 10 The stop 180 is shown. In this embodiment, the stop 180 is mounted to the mounting bracket 141. The stop 180 is preferably positioned adjacent to a first transition ramp 143 of the multifaceted ramp 140. The stop 180 may be a tab or other such protrusion. The stop 180 may be integrally formed with the mounting bracket 141.

[0033] The addition of the stop 180 reduces the bending of the entire multifaceted ramp 140 at the connection point 191 between the multifaceted ramp 140 and the support 141. In addition, the stop 180 reduces the bending at the first transition ramp 143, resulting in a more uniform stress distribution on the multifaceted ramp 140.

[0034] Figure 6 Examples of TJPDs 190a and 190b are shown, where they are fixed-position rollers. Each TJPD 190a and 190b includes a bolt 195 fixedly mounted to the transfer case 107. Around and freely rotating on the bolt 195 is a rolling element 196. The rolling element 196 preferably has an elastomeric coating.

[0035] TJPDs 190a and 190b are positioned at the driven sprocket 6. Regardless of the transfer case azimuth angle, TJPDs 190a and 190b are located at the inlet and / or outlet of the driven sprocket. More specifically, TJPD 190a is located at the position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 first engages with the slack strand 8b of the chain 8 (e.g., when the chain 8 enters the driven sprocket 6), and TJPD 190b is located at the position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 last engages with the tight strand 8a of the chain (e.g., at the outlet of the chain 8).

[0036] Figure 7 One embodiment is shown, wherein TJPD 180 is a ramp roller TJPD. TJPD 180 is mounted in the transfer case 107 and adjacent to the chain 8 and the driven sprocket 6.

[0037] Mounting bracket 151 is at approximately a 90-degree angle to a first flat surface 152, which transitions to a first transition ramp 153, an inclined ramp 154, and a conforming roller retainer 155 that receives the conforming roller 156. In other words, the mounting bracket is the vertical portion of an "L," and the first transition ramp 153 is the horizontal portion of an "L." The mounting angle of bracket 151 relative to the conforming roller 156 can be any angle that both mounts TJPDs 150a and 150b to the transfer case 107 and allows the conforming roller 156 to engage with the chain 8.

[0038] Regardless of the transfer case azimuth angle, the TJPD 180 is preferably mounted such that the conforming roller 156 is diametrically positioned at the driven sprocket 6 and / or drive sprocket 2 and at the inlet and / or outlet of the driven sprocket 6 or drive sprocket 2. More specifically, at least the first TJPD 180 is located at a position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 first engages with the slack strand 8b of the chain 8 (e.g., at the inlet of the driven sprocket 6). The second TJPD 180 may be located at a position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 last engages with the tight strand 8a of the chain (e.g., at the outlet of the driven sprocket 6).

[0039] The conforming roller 156 can be made of plastic. Alternatively, the conforming roller 156 can be made of plastic or other materials and coated with an elastomer to reduce wear. Figure 7 and 13 As shown, the conforming roller 156 can be a single roller mounted to the conforming roller retainer 155 or multiple different rollers mounted on either side of the conforming roller retainer 155.

[0040] exist Figure 13In the alternative embodiment shown, the TJPD 170 with face conforming roller 156 is biased by spring 157 to engage with chain 8, further concentrating the accumulated system slack at a specific location on drive sprocket 6 or driven sprocket 2 to reduce contact force. Face conforming roller 156 is received on conforming roller retainer 155 integrally formed with arm 159. Face conforming roller 156 has reduced friction relative to chain 8 compared to a chain sliding across a conventional tension arm.

[0041] Arm 159 is pivotally attached to mounting bracket 151 via pivot pin 158, which is received within a pivot hole 168 of arm 159 at the second end 159b of arm 159, opposite the conforming roller retainer 155 at the first end 159a. Pivot pin 158 is mounted to mounting bracket at a 90-degree angle. Arm 159 is preferably rigid.

[0042] A spring 157 is present between the first end 159a of the arm 159 and the bracket 151 to bias the arm 159 and thus the conforming roller 156. The spring force at the inlet and outlet of each sprocket 2, 6 or chain 8 and either the driven sprocket 6 or the driving sprocket 2 can be different or the same. The spring 157 can be a torsion spring, a leaf spring, or other type of spring. The use of the spring 157 increases compliance, allowing for a reduction in contact force. Furthermore, the spring 157 used can have a limited range of travel, such that in a first position, the spring 157 biases the conforming roller 156 so that the conforming roller 156 is not engaged with the chain 8 and there is a gap between the conforming roller 156 and the chain 8. When the chain 8 contacts the conforming roller 156 with sufficient force to overcome the spring preload, the conforming roller 156 moves to a second position by rotating the arm 159 connected to the conforming roller retainer 155, such that the arm 159 pivots relative to the mounting bracket 151 via the pivot pin 158. The spring preload is used to prevent chain skipping. The spring load is preferably adjusted to the required force to prevent skipping and thus reduce or prevent chain slack from accumulating at the driven sprocket 6.

[0043] Regardless of the transfer case azimuth angle, the TJPD 170 is preferably mounted such that the conforming roller 156 is diametrically positioned at the driven sprocket 6 and / or drive sprocket 2 and located at the inlet and / or outlet of the driven sprocket 6 or drive sprocket 2. More specifically, at least the first TJPD 170 is located at a position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 first engages with the slack strand 8b of the chain 8 (e.g., when the chain 8 enters the inlet of the driven sprocket 6). The second TJPD 170 may be located at a position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 last engages with the tight strand 8a of the chain (e.g., when the chain 8 leaves the outlet of the driven sprocket 6).

[0044] Figures 8a-8bAnother embodiment of the TJPD is shown. In this embodiment, the TJPD is a bias buffer 160. The bias buffer 160 is mounted to the transfer case 107 of the drivetrain. The bias buffer 160 has a body 161 with a first end 162, a second end 163 opposite to the first end 162, a length L between the first end 162 and the second end 163, a buffer surface 164, and a second surface 165 opposite to the buffer surface 164. Along the buffer surface 164, there exists a desired angle α (alpha) between the first end 162 and the second end 163 relative to a straight line 193 extending from the first end 162 to the second end 163 and parallel to the buffer surface 164. The desired angle α is between 0 and 5 degrees, and more preferably, greater than 0 degrees.

[0045] The bias damper 160 creates a desired angle α between the path of chain 8 and the damper face 164, such that a desired angle α exists between the chain path and the damper face 164. The shape of the damper face 164 causes it to be closer to the chain 8 near the driven sprocket 6 than to the drive sprocket 2. The desired angle α forces chain slack to accumulate near the chain exit of the drive sprocket 2, as indicated by reference numeral 32. When tension is applied to adjacent chain strands, the bias damper 160 is completely outside the chain path, as shown in the figure. Figure 8a As shown.

[0046] When tension is applied to the opposing strands, slack will accumulate on the strands adjacent to the bias buffer 160, and the intended angle α(a) of the bias buffer 160 forces excess chain to accumulate at a known location to improve tooth skipping, such as... Figure 8b As shown. Therefore, slack accumulation exists only near drive sprocket 2 and can be used to control chain slack within the transfer case, so that chain slack accumulates only on drive sprocket 2, resulting in higher runout torque. This higher runout torque capability allows for a reduction in chain width.

[0047] It should be noted that the bias damper 160 can also be installed at a target distance relative to the driven sprocket, and within the target or specific chain-damper gap, to prevent slack accumulation relative to the driven sprocket 6 and force the slack accumulation closer to the drive sprocket 2, as shown below relative to Figures 11a-11b As stated above.

[0048] Figures 11a-11bAn embodiment of a TJPD (Transfer Junction Damper) is shown, positioned at a specific or target distance relative to the driven sprocket 6 and within a target or specific chain-buffer gap to prevent slack accumulation relative to the driven sprocket 6 and to force the slack accumulation closer to the drive sprocket 2. The buffer 200 has a body 201 with a first end 202 and a second end 203, and a first surface 205 and a second surface 204. The second surface 204 is adjacent to the chain 8. Optionally, the second surface 204 may include a pad or elastomer surface to reduce noise vibration roughness (NVH) problems. The buffer is positioned at a chain gap distance g1 and biased at a distance d1 from the driven sprocket 6. These distances g1 and d1 are determined by the mounting positions of the chain 8 and sprockets 2 and 6 relative to the transfer case 107.

[0049] The buffer 200 is positioned between the driven sprocket 6 and the drive sprocket 2, at a specific distance d1 from the centerline C1 of the driven sprocket 6, and at a specific gap distance g1 between the second face 204 and the chain 8. In one example, the gap distance g1 between the chain 8 and the buffer 200 is in the range of 0-7 mm. In another embodiment, this range can be 0-1 mm. In yet another embodiment, this range can be 0-2 mm. In yet another example, the gap distance g1 is 0.5 mm or less. By setting the gap distance between the chain 8 and the buffer 200, the contact force and wear of the buffer 200 are reduced. Using the chain pitch length, the distance d1 can be approximately two chain pitch lengths. For example, for a 9.525 mm pitch chain, d1 is approximately 19 mm. For an 11.039 mm pitch chain, the distance d1 is approximately 22 mm.

[0050] When tension is applied to the opposing chain strands adjacent to the buffer 200, slack will accumulate on the chain strands adjacent to the buffer 200 due to the gap distances g1 and d1 forcing excess chain to accumulate at a known location near the drive sprocket 2, resulting in higher runout torque. This higher runout torque capability allows for the use of a reduced chain width.

[0051] Figure 9 illustrates a conventional or traditional damper. The conventional damper 50 is not angled, but rather straight or approximately 180 degrees along its entire length between the first end 51 and the second end 52, such that the entire damper surface 53 interacts with the chain strand 8, and there is a small gap of approximately 0.1 mm between the conventional damper 50 and the chain. Slack accumulates near the drive sprocket 2 (shown by reference numeral 32) and near the driven sprocket 6 (shown by reference numeral 30). Therefore, slack is allowed to accumulate near both the drive sprocket 2 and the driven sprocket 6, and tooth skipping can occur on either sprocket.

[0052] Figure 12A TJPD 300 is shown mounted to the transfer case 107 and located near the chain 8 and driven sprocket 6. In this embodiment, the TJPD 300 is an integral multifaceted ramp 310 with a mounting bracket 301 and a buffer 302.

[0053] Mounting bracket 301 can be integrally formed with multi-faceted ramp 310. In addition, mounting bracket 301 can be integrally formed with buffer 302.

[0054] The buffer 302 has a first flat surface 302a and an opposing second flat surface 302b adjacent to the chain 8. A pad or elastic pad 303 is attached to the second flat surface 302b. The pad 303 contacts the chain 8.

[0055] The multifaceted ramp 310 is also attached to the mounting bracket 301. The multifaceted ramp 310 has a first main body portion 304 with a flat surface connected to the mounting bracket 301 and an inclined second main body portion 305. The inclined second main body portion 305 is connected to a first transition ramp 306, which is connected to a first flat surface 307. A pad or elastomer surface 309 is attached to the surface 307a of the second flat surface 307.

[0056] The pad 309 is installed with a small offset from the chain 8. For example, the gap between the pad 309 and the chain 8 is between 0.5 and 1.5 mm. As the chain 8 wears or stretches, the gap decreases, and contact between the chain 8 and the pad 309 is possible during normal operation of the chain 8. As the chain 8 rotates and tooth skipping occurs, the pad 309 of the TJPD 300 applies a reaction force to the chain 8 to keep the chain 8 engaged with the driven sprocket 6 and prevent chain slack from accumulating on the driven sprocket 6. The pad 303 remains in contact with the chain 8 during normal chain operation. The pad 303 acts as a damper to attenuate chain resonance and contacts the chain when the chain enters a resonant state.

[0057] Regardless of the transfer case azimuth angle, the TJPD 300 is preferably installed such that the pad 309 of the multifaceted ramp 310 is positioned along the diameter of the driven sprocket 6 or the drive sprocket 2 and is located at the inlet and / or outlet of the driven sprocket.

[0058] More specifically, at least the first TJPD 300 is located at the position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 first engages with the slack chain strand 8b of the chain 8 (e.g., at the entrance of the driven sprocket 6). The second TJPD 300 may be located at the position where the chain 8 is tangent to the driven sprocket 6 when the driven sprocket 6 last engages with the tight chain strand 8a of the chain (e.g., at the exit of the driven sprocket 6).

[0059] In one embodiment, the mounting bracket 301 and the buffer 302 are formed from a single sheet of steel. The mounting bracket 301 is at approximately a 90-degree angle to the first flat surface 302a of the buffer 302.

[0060] The TJPD 300’s damper 302 provides additional noise vibration and roughness (NVH) reduction by controlling the chain strand resonance associated with the chain system, while the TJPD 300’s multifaceted ramp 310 limits the accumulation of slack on the driven sprocket 6.

[0061] Although two TJPDs 130, 140, 150, 160, 170, 180, 190, 200, 300 are shown on either side of the driven sprocket 6, a single TJPD can be positioned at a specific or target distance relative to the driven sprocket 6.

[0062] In another embodiment, a single TJPD or two TJPDs may be shown on either side of the drive sprocket 2 to force cumulative slack on the driven sprocket 6.

[0063] Although not shown, in alternative embodiments, the two TJPD devices mounted along the diameter of the driven sprocket and / or drive sprocket can be different devices. Any combination of TJPDs disclosed in this application can appear at the inlet and outlet of the chain with the driven sprocket 6. Thus, the first TJPD at the initial engagement of the driven sprocket 6 with the slack strand 8b of the chain 8 (e.g., at the inlet of the chain 8 entering the driven sprocket 6) and the second TJPD at the position where the chain 8 is tangent to the driven sprocket 6 at the final engagement of the driven sprocket 6 with the tight strand 8a of the chain (e.g., at the outlet of the chain 8 leaving the driven sprocket 6) can be the same or different.

[0064] For example, an integrated fixed-position TJPD 130 can be installed at the initial engagement point of the driven sprocket 6 and the slack chain strand 8b of the chain 8 (e.g., at the entrance of the chain 8 into the driven sprocket 6), and a second TJPD can be an L-shaped integrated multi-faceted ramp TJPD 140 installed at the final engagement point of the driven sprocket 6 and the tight chain strand 8a of the chain. In another example, a fixed-position conforming roller TJPD 150 can be installed at the initial engagement point of the driven sprocket 6 and the slack chain strand 8b of the chain 8 (e.g., at the entrance of the chain 8 into the driven sprocket 6), and a second TJPD can be a buffer TJPD 300 installed at the final engagement point of the driven sprocket 6 and the tight chain strand 8a of the chain. The above examples are not limiting, and other combinations are possible.

[0065] Furthermore, the TJPDs mounted on the opposite chain strands can also differ along the chain span between the driven and drive sprockets. For example, one TJPD could be a bias buffer TJPD 160, and the opposite TJPD mounted relative to the opposite chain strand could be a buffer TJPD 200. The above examples are not limiting, and other combinations are possible.

[0066] In yet another embodiment, individual TJPDs 130, 140, 150, 160, 170, 180, 190, 300 may be placed at the entrance of the slack strand 8b that engages with the driven sprocket 6.

[0067] In yet another embodiment, individual TJPDs 160, 200 are positioned relative to one of the strands 8a, 8b of chain 8.

[0068] In another embodiment, when the transfer case is installed in a horizontal position, the opposite midpoints correspond to the 12 o'clock and 6 o'clock positions along the center diameter of the driven sprocket 6 and / or the drive sprocket 2. The TJPD in the above embodiment is installed at the opposite midpoint of the driven sprocket 6 and / or the drive sprocket 2.

[0069] In another embodiment, when the transfer case is installed in the vertical position, the opposite midpoints correspond to the 3 o'clock and 9 o'clock positions of the driven sprocket 6 and / or the drive sprocket 2. The TJPD in the above embodiment is installed at the opposite midpoints of the driven sprocket 6 and / or the drive sprocket 2.

[0070] Therefore, it should be understood that the embodiments of the invention described herein are merely illustrative of the application of the principles of the invention. Reference to the details of the illustrated embodiments herein is not intended to limit the scope of the claims, which themselves set forth those features considered essential to the invention.

Claims

1. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes: The mounting bracket fixed to the transfer case; and The ramp connected to the mounting bracket includes: at least a ramp, a first flat surface and a second flat surface, the second flat surface having a face adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket, and the first flat surface being perpendicular to the mounting bracket.

2. The chain drive system of claim 1, wherein the second tooth skip protection device comprises a buffer fixed to the transfer case and positioned at a distance from the chain, the buffer having a body having a surface adapted to engage the chain to maintain engagement of the chain with the driven sprocket and prevent chain slack from accumulating on the driven sprocket.

3. The chain drive system according to claim 1, wherein the second tooth skip protection device comprises: Mounting bracket fixed to the transfer case; as well as The ramp connected to the mounting bracket includes: at least a ramp, a first flat surface and a second flat surface, the second flat surface having a face adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket, and the first flat surface being perpendicular to the mounting bracket.

4. The chain drive system according to claim 1, further comprising a first transition ramp between the first flat surface and the ramp, and a second transition ramp between the second flat surface and the ramp.

5. The chain drive system of claim 4 further includes a stop extending axially from the mounting bracket and aligned with the first transition ramp of the ramp.

6. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes: Mounting bracket fixed to the transfer case; The ramp connected to the mounting bracket includes: at least a first flat surface, an inclined ramp, and a conforming roller retainer; and At least one roller mounted on the compliant roller retainer is adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; The first flat surface is perpendicular to the mounting bracket.

7. The chain drive system according to claim 6, wherein, The second tooth skip protection device includes: Mounting bracket fixed to the transfer case; The ramp connected to the mounting bracket includes: at least a first flat surface, an inclined ramp, and a conforming roller retainer; and At least one roller mounted on the compliant roller retainer is adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; The first flat surface is perpendicular to the mounting bracket.

8. The chain drive system according to claim 7, wherein the first tooth skipping protection device and the second tooth skipping protection device each comprise: Bolts fixed to the transfer case and rolling elements capable of rotating around the bolts.

9. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes: The mounting bracket fixed to the transfer case has a pivot pin extending vertically from it; The arm includes a body having a first end, a second end, a roller retainer located at the second end, and a hole for receiving the pivot pin at the first end; and At least one roller mounted on the roller retainer is adapted to engage the chain to maintain engagement of the chain with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; and A torsion spring, mounted between the mounting bracket and the arm, biases the first end of the arm on the pivot toward the chain.

10. The chain drive system according to claim 9, wherein, The second tooth skip protection device includes: The mounting bracket fixed to the transfer case has a pivot pin extending vertically from it; The arm includes a body having a first end, a second end, a roller retainer located at the second end, and a hole for receiving the pivot pin at the first end; and At least one roller mounted on the roller retainer is adapted to engage the chain to maintain engagement of the chain with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; and A torsion spring, mounted between the mounting bracket and the arm, biases the first end of the arm on the pivot toward the chain.

11. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes: Mounting bracket fixed to the transfer case; The ramp connected to the mounting bracket includes: a first flat surface of a first main body portion connected to an inclined ramp of the second main body portion, the inclined ramp of the second main body portion connected to a second flat surface, the second flat surface having a face adapted to engage the chain to maintain engagement of the chain with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; and A buffer, fixed to the mounting bracket and parallel to the first flat surface of the first main body portion of the ramp, the buffer having a face adapted to engage the chain between the driven sprocket and the drive sprocket; The first flat surface is perpendicular to the mounting bracket.

12. The chain drive system of claim 11, further comprising a first pad mounted to the face of the buffer to engage the chain and a second pad mounted to the second flat surface of the ramp.

13. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes a buffer fixed to the transfer case and positioned at a distance from the chain. The buffer has a body with a surface adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket. The second tooth skip protection device includes: The mounting bracket fixed to the transfer case; and The ramp connected to the mounting bracket includes: at least a first flat surface, an inclined ramp, and a second flat surface, the second flat surface having a face adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; wherein the first flat surface is perpendicular to the mounting bracket.

14. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes a buffer fixed to the transfer case and positioned at a distance from the chain. The buffer has a body with a surface adapted to engage the chain to maintain engagement between the chain and the driven sprocket and prevent chain slack from accumulating on the driven sprocket. The second tooth skip protection device includes: Mounting bracket fixed to the transfer case; The ramp connected to the mounting bracket includes: a first flat surface, an inclined ramp, and a conforming roller retainer; and At least one roller mounted on the compliant roller retainer is adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; wherein the first flat surface is perpendicular to the mounting bracket.

15. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes a buffer fixed to the transfer case and positioned at a distance from the chain. The buffer has a body with a surface adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket. The second tooth skip protection device includes: The mounting bracket fixed to the transfer case has a pivot pin extending vertically therefrom; An arm includes a body having a first end, a second end, a roller retainer located at the second end, and a hole for receiving the pivot pin at the first end; and At least one roller mounted on the roller retainer is adapted to engage the chain to maintain engagement of the chain with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; and A torsion spring, mounted between the mounting bracket and the arm, biases the first end of the arm on the pivot toward the chain.

16. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes a buffer fixed to the transfer case and positioned at a distance from the chain. The buffer has a body with a surface adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket. The second tooth skip protection device includes: Mounting bracket fixed to the transfer case; The ramp connected to the mounting bracket includes: a first flat surface of a first main body portion connected to an inclined ramp of a second main body portion, the inclined ramp of the second main body portion being connected to a second flat surface via a first transition ramp, the second flat surface having a surface adapted to engage the chain to maintain engagement of the chain with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; and A buffer, fixed to the mounting bracket and parallel to the first flat surface of the first main body portion of the ramp, the buffer having a face adapted to engage the chain between the driven sprocket and the drive sprocket; The first flat surface is perpendicular to the mounting bracket.

17. The chain drive system of claim 16, further comprising a first pad mounted to the face of the buffer to engage the chain and a second pad mounted to the second flat surface of the ramp.

18. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes: The mounting bracket fixed to the transfer case; and The ramp connected to the mounting bracket includes: a first flat surface of a first body portion connected to an inclined ramp of a second body portion, the inclined ramp of the second body portion connected to a second flat surface, the second flat surface having a face adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket.

19. The chain drive system of claim 18 further includes a stop that extends axially from the mounting bracket and is aligned with the ramp.

20. The chain drive system of claim 18, further comprising a second tooth skip protection device installed at the second engagement point of the driven sprocket where the tension strand of the chain leaves the driven sprocket, the second tooth skip protection device comprising: The mounting bracket fixed to the transfer case has a pivot pin extending vertically therefrom; An arm includes a body having a first end, a second end, a roller retainer located at the second end, and a hole for receiving the pivot pin at the first end; as well as At least one roller mounted on the roller retainer is adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; as well as A torsion spring, mounted between the mounting bracket and the arm, biases the first end of the arm on the pivot toward the chain.

21. The chain drive system of claim 18, further comprising a second tooth skip protection device installed at the second engagement point of the driven sprocket where the tension strand of the chain leaves the driven sprocket, the second tooth skip protection device comprising: Mounting bracket fixed to the transfer case; The ramp connected to the mounting bracket includes: a first flat surface of a first main body portion connected to an inclined ramp of the second main body portion, the inclined ramp of the second main body portion connected to a second flat surface, the second flat surface having a face adapted to engage the chain to maintain engagement of the chain with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; and A buffer, fixed to the mounting bracket and parallel to the first flat surface of the first main body portion of the ramp, the buffer having a face adapted to engage the chain between the driven sprocket and the drive sprocket; The first flat surface is perpendicular to the mounting bracket.

22. The chain drive system of claim 21, further comprising a first pad mounted to the face of the buffer to engage the chain and a second pad mounted to the second flat surface of the ramp.

23. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes: Mounting bracket fixed to the transfer case; The ramp connected to the mounting bracket includes: at least a first flat surface, an inclined ramp, and a conforming roller retainer; and At least one roller mounted on the compliant roller retainer is adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; The first flat surface is perpendicular to the mounting bracket.

24. The chain drive system of claim 23, further comprising a second tooth skip protection device installed at the second engagement point of the driven sprocket where the tension strand of the chain leaves the driven sprocket, the second tooth skip protection device comprising: Mounting bracket fixed to the transfer case; The ramp connected to the mounting bracket includes: a first flat surface of a first main body portion connected to an inclined ramp of the second main body portion, the inclined ramp of the second main body portion connected to a second flat surface, the second flat surface having a face adapted to engage the chain to maintain engagement of the chain with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; and A buffer, fixed to the mounting bracket and parallel to the first flat surface of the first main body portion of the ramp, the buffer having a face adapted to engage the chain between the driven sprocket and the drive sprocket; The first flat surface is perpendicular to the mounting bracket.

25. The chain drive system of claim 24, further comprising a first pad mounted to the face of the buffer to engage the chain and a second pad mounted to the second flat surface of the ramp.

26. The chain drive system of claim 23, further comprising a second tooth skip protection device installed at the second engagement point of the driven sprocket where the tension strand of the chain leaves the driven sprocket, the second tooth skip protection device comprising: The mounting bracket fixed to the transfer case has a pivot pin extending vertically therefrom; An arm includes a body having a first end, a second end, a roller retainer located at the second end, and a hole for receiving the pivot pin at the first end; as well as At least one roller mounted on the roller retainer is adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; as well as A torsion spring, mounted between the mounting bracket and the arm, biases the first end of the arm on the pivot toward the chain.

27. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes: The mounting bracket fixed to the transfer case has a pivot pin extending vertically from it; An arm includes a body having a first end, a second end, a roller retainer located at the second end, and a hole for receiving the pivot pin at the first end; and At least one roller mounted on the roller retainer is adapted to engage the chain to maintain engagement of the chain with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; and A torsion spring, mounted between the mounting bracket and the arm, biases the first end of the arm on the pivot toward the chain.

28. A chain drive system in a transfer case, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; The first tooth skip protection device is installed at the initial engagement point of the slack chain strand of the chain with the driven sprocket, where the chain and the driven sprocket are tangent. This causes the chain to accumulate slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. as well as The second tooth skip protection device is installed at the second engagement point of the driven sprocket where the tight chain strand of the chain leaves the driven sprocket, causing the chain to accumulate slack near the driven sprocket and increasing the tooth skip torque of the chain drive system; The first tooth skip protection device includes: Mounting bracket fixed to the transfer case; The ramp connected to the mounting bracket includes: a first flat surface of a first main body portion connected to an inclined ramp of the second main body portion, the inclined ramp of the second main body portion connected to a second flat surface, the second flat surface having a face adapted to engage the chain to maintain engagement of the chain with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; and A buffer, fixed to the mounting bracket and parallel to a first flat surface of the first main body portion of the ramp, the buffer having a face adapted to engage the chain between the driven sprocket and the drive sprocket; The first flat surface is perpendicular to the mounting bracket.

29. The chain drive system of claim 28, further comprising a first pad mounted to the face of the buffer to engage the chain and a second pad mounted to the second flat surface of the ramp.

30. A chain drive system mounted in a transfer case on an engine, the chain drive system comprising: Drive sprocket; Driven sprocket; A chain connecting the drive sprocket to the driven sprocket, the chain having slack strands between the driven sprocket and the drive sprocket, and tight strands between the driven sprocket and the drive sprocket; A first tooth skip protection device is installed between the driven sprocket and the drive sprocket on the slack chain strand of the chain. The tooth skip protection device is installed at the first engagement point of the slack chain strand of the chain with the driven sprocket, at the position where the chain and the driven sprocket are tangent, so that the chain accumulates slack near the driven sprocket, increasing the tooth skip torque of the chain drive system. The first tooth skip protection device is a bias damper, comprising: a body having a first end, a second end, a length between the first end and the second end, and a surface adapted to contact the chain between the driven sprocket and the drive sprocket; the surface extends at an angle along the length between the first end and the second end relative to a straight line extending from the first end to the second end parallel to the surface of the damper; The face of the bias buffer is adapted to engage the chain to keep the chain engaged with the driven sprocket.

31. The chain drive system according to claim 30, further comprising a second tooth skip protection device installed at the second engagement point of the driven sprocket where the tension strand of the chain leaves the driven sprocket, the second tooth skip protection device comprising: A buffer, the buffer comprising: a body having a first end, a second end, a length between the first end and the second end, and a surface adapted to contact the chain between the driven sprocket and the drive sprocket; the surface extending at an angle along the length between the first end and the second end relative to a straight line extending from the first end to the second end parallel to the surface of the buffer.

32. The chain drive system of claim 30, further comprising a second tooth skip protection device, installed at a distance from the centerline of the driven sprocket at a second engagement point of the tensioning strand of the chain away from the driven sprocket and having a gap relative to the tensioning strand of the chain, the second tooth skip protection device comprising: A buffer, the buffer comprising: a body having a first end, a second end, a length between the first end and the second end, and a face adapted to contact the chain between the driven sprocket and the drive sprocket; wherein the face of the buffer is adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket.

33. The chain drive system according to claim 30, further comprising a second tooth skip protection device installed at the second engagement point of the driven sprocket where the tension strand of the chain leaves the driven sprocket, the second tooth skip protection device comprising: Mounting bracket fixed to the transfer case; The ramp connected to the mounting bracket includes: at least a ramp, a first flat surface and a second flat surface, the second flat surface having a face adapted to engage the chain to keep the chain engaged with the driven sprocket and prevent chain slack from accumulating on the driven sprocket, and the first flat surface being perpendicular to the mounting bracket.

34. The chain drive system of claim 30, further comprising a second tooth skip protection device installed at the second engagement point of the driven sprocket where the tension strand of the chain leaves the driven sprocket, the second tooth skip protection device comprising: Mounting bracket fixed to the transfer case; The ramp connected to the mounting bracket includes: a first flat surface of a first main body portion connected to an inclined ramp of the second main body portion, the inclined ramp of the second main body portion connected to a second flat surface, the second flat surface having a face adapted to engage the chain to maintain engagement of the chain with the driven sprocket and prevent chain slack from accumulating on the driven sprocket; and A buffer, fixed to the mounting bracket and parallel to the first flat surface of the first main body portion of the ramp, the buffer having a face adapted to engage the chain between the driven sprocket and the drive sprocket; The first flat surface is perpendicular to the mounting bracket.

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