Rotary lock system with CAM actuator

Abstract

A rotary locking device (100) is provided herein. The device includes a pawl (109) pivotably coupled to a pivot to move between an engaged position and a disengaged position relative to a gear (115), a cam arm (108) rigidly coupled to the pawl (109), a cam (104) to move the pawl (109) from the engaged position to the disengaged position, a motor (106) to rotate the cam (104) to move the pawl (109) from the engaged position to the disengaged position, and a biasing element (112) coupled to the pawl (109) to move the pawl (109) from the disengaged position to the engaged position.

Description

ROTARY LOCK SYSTEM WITH CAM ACTUATORCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 651,758, filed May 24, 2024, which is hereby incorporated by reference in its entirety.BACKGROUND

[0002] Rotary lock systems are utilized in various applications to selectively control the rotation of mechanical components. These systems typically employ a pawl mechanism that engages with a gear or other toothed element to arrest or allow rotation. Such locking mechanisms find use in diverse fields including automotive systems, industrial machinery, and consumer products where precise control over rotational movement is desired. The design and operation of rotary lock systems can impact factors such as engagement reliability, wear characteristics, and overall system efficiency. As mechanical systems continue to evolve, there is ongoing interest in refining rotary lock mechanisms to enhance their performance and durability across different operating conditions and applications.SUMMARY

[0003] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0004] Some exemplary embodiments are related to a rotary locking device. The device includes a pawl pivotably coupled to a pivot to move between an engaged position and a disengaged position relative to a gear, a cam arm rigidly coupled to the pawl, a cam to move the pawl from the engaged position to the disengaged position, a motor to rotate the cam to move the pawl from the engaged position to the disengaged position, and a biasing element coupled to the pawl to move the pawl from the disengaged position to the engaged position.

[0005] Other exemplary embodiments are related to a method of operating a device. The method includes pivoting a pawl coupled to a pivot to move between an engaged position and a disengaged position relative to a gear, rotating, using a motor, a cam to engage a cam arm rigidly coupled to the pawl to move the pawl from the engaged position to the disengaged position, andbiasing the pawl via a biasing element to move the pawl from the disengaged position to the engaged position.

[0006] Still further exemplary embodiments are related to a brake system. The brake system includes a gear, a brake coupled to the gear, a pawl pivotably coupled to a pivot to move between an engaged position and a disengaged position relative to the gear, a cam arm rigidly coupled to the pawl, a cam to move the pawl from the engaged position to the disengaged position, a motor to rotate the cam to move the pawl from the engaged position to the disengaged position, and a biasing element coupled to the pawl to move the pawl from the disengaged position to the engaged position.

[0007] The foregoing general description of the illustrative embodiments and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and are not restrictive.BRIEF DESCRIPTION OF FIGURES

[0008] Non-limiting and non-exhaustive examples are described with reference to the following figures.

[0009] FIG. 1 A shows a top view of a rotary lock system in an engaged state.

[0010] FIG. IB shows a top view of a rotary lock system in a disengaged state.

[0011] FIG. 1C shows a top view of a rotary lock system in a ratcheting state.

[0012] FIG. 2A-2F show various views of a cam and motor assembly for a rotary lock system.

[0013] FIG. 3 shows an isometric view of a cam and motor system assembly with a helical cam.

[0014] FIG. 4 shows an isometric view of a motor and cam assembly with a bevel gear arrangement.

[0015] FIG. 5 shows a block diagram of a brake system implemented in a vehicle.DETAILED DESCRIPTION

[0016] The following description sets forth exemplary aspects of the present disclosure. It should be recognized, however, that such description is not intended as a limitation on the scopeof the present disclosure. Rather, the description also encompasses combinations and modifications to those exemplary aspects described herein.

[0017] Conventional rotary lock systems typically utilize a pawl coupled to a piston, such as a solenoid, to control engagement with a gear. The piston extends to disengage the pawl from the gear and retracts to engage the pawl with the gear. However, this arrangement presents certain challenges in operation and durability. The engagement member of the pawl may not fully seat between the gear teeth during engagement, instead abutting the gear teeth and resulting in incomplete engagement. This incomplete engagement introduces unwanted forces into the system, potentially leading to increased wear, reduced efficiency, or compromised locking performance. Additionally, the piston must remain in a retracted state to maintain pawl engagement with the gear, subjecting the piston and associated components to prolonged stress, potentially accelerating wear and reducing the overall lifespan of the system.

[0018] To address these challenges, rotary lock systems as described herein may utilize a cambased mechanism for controlling pawl engagement. The system may comprise a pawl pivotably coupled to a pivot to move between an engaged position and a disengaged position relative to a gear, with a cam arm rigidly coupled to the pawl and a cam to move the pawl from the engaged position to the disengaged position. A motor may rotate the cam while a biasing element, such as a spring, moves the pawl from the disengaged position to the engaged position. In this arrangement, the pawl may return to the engaged position without actuation by the cam, moves into full engagement with gear teeth when allowed, and the system doesn't require constant actuation to maintain engagement, potentially reducing wear and extending operational life. The rotary lock system may be utilized in various applications including automotive parking brakes, industrial machinery, robotics, and consumer appliances where selective locking of rotating components is required.

[0019] FIGS. 1A-1C illustrate various views of an example rotary lock system 100. FIG. 1 A shows the rotary lock system 100 in an engaged state, FIG. IB shows the rotary lock system 100 in a disengaged state, and FIG. 1C shows the rotary lock system 100 in a ratcheting state.

[0020] In some implementations, a device may comprise a pawl pivotably coupled to a pivot to move between an engaged position and a disengaged position relative to a gear. The rotary lock system 100 may include a pawl 109 positioned at one end of a cam arm 108. The pawl 109 mayinclude an engagement member 110 configured to engage with teeth of a gear 115. The pawl 109 may be mounted to a fixed structure 114 via a pawl joint 118 that may allow pivoting movement of the pawl 109. For example, the fixed structure 114 may comprise a housing, frame, hard point, or other suitable location for a fulcrum rigidly coupled to a vehicle or other device using the rotary lock system 100. A biasing element coupled to the pawl may move the pawl from the disengaged position to the engaged position. For example, a spring 112 may connect between a spring retaining member 113 and the cam arm 108 to provide a biasing force. The gear 115 may be connected to various components requiring selective locking, such as a brake rotor in a vehicle parking brake system, a spindle drive for a vehicle brake, a planetary gear stage in an actuator assembly, or a bearing sleeve for controlling brake lining movement. The gear 115 may be coupled to any component or system to be locked. For example, in some implementations, the gear 115 may be part of a brake caliper assembly or connected to an actuating carriage for applying brake linings to a brake disc. As further examples, in some implementations, the gear 115 may be connected to a locking mechanism for industrial equipment, such as a safety interlock system for manufacturing machinery or a position control device for robotic arms in automated assembly lines.

[0021] In some implementations, the pawl may comprise an engagement member having a first surface to engage with teeth of the gear to arrest rotation of the gear in a first direction and a second surface to engage with the teeth of the gear to allow ratcheting rotation of the gear in a second direction. For example, the engagement member 110 may include a sloped upper surface to allow ratcheting and a flat bottom surface to arrest rotation of the gear 115. This configuration may enable the rotary lock system 100 to transition between engaged, disengaged, and ratcheting states. In some examples, the engagement member 110 may be formed from a hardened metal such as steel or stainless steel. The engagement member 110 may be integrally formed with the pawl 109 or may be a separate component attached to the pawl 109 using fasteners, adhesives, or other attachment methods. In some implementations, the engagement member 110 may include two locking surfaces instead of a locking surface and a ratcheting surface. For instance, the engagement member 110 may have a symmetrical profile with two flat surfaces that prevent rotation in both directions when engaged. Alternatively, the engagement member 110 may include a stepped profile with primary and secondary locking surfaces at different heights to provide redundant locking capability in critical applications.

[0022] In the ratcheting state shown in FIG. 1 C, rotation of the gear 1 15 in a counterclockwise direction may cause the teeth of gear 115 to engage with the sloped upper edge of the engagement member 110. For example, the flat lower edge of the engagement member 110 may prevent gear 115 from rotating in a clockwise direction. This configuration may allow one-way rotation of gear 115 when the cam 104 may be disengaged with the distal portion 111. The angle of the sloped upper edge may be designed to balance the ease of ratcheting with the security of engagement. In some examples, the sloped upper edge may have an angle between 30 and 60 degrees relative to the flat lower edge. The engagement member 110 may include a rounded or chamfered transition between the sloped upper edge and the flat lower edge to reduce wear during operation.

[0023] In some implementations, a biasing element may be coupled to the pawl to move the pawl from the disengaged position to the engaged position. The biasing element may comprise various types of springs or resilient members. The spring 112 may serve as a biasing element. While shown as a torsion spring in the figures, the biasing element may be any type of spring, such as a compression spring, extension spring, or leaf spring. In some examples, the biasing element may be a compression spring, torsion spring, coil spring, a wave spring, etc. The spring 112 may be made from various materials including spring steel or stainless steel. The spring 112 may be selected based on a desired spring rate, operating environment, and durability requirements. In some cases, multiple springs may be used in parallel or in series to achieve the desired biasing force. The biasing element may be configured to provide sufficient force to ensure reliable engagement of the pawl 109 with the gear 115 while allowing for smooth disengagement when the cam 104 may act upon the cam arm 108.

[0024] In the engaged state shown in FIG. 1A, the engagement member 110 of the pawl 109 may be positioned between teeth of the gear 115, preventing rotation of the gear 115. In some examples, the spring 112 may provide a biasing force that may urge the pawl 109 toward engagement with the gear 115. The engagement member 110 may fully engage with the gear teeth, creating a mechanical lock that may prevent rotation in either direction. In some implementations, the engagement depth between the engagement member 110 and the gear 115 may be designed to provide sufficient locking force while allowing for reliable disengagement when needed.

[0025] In some implementations, the cam arm may be coupled to the pawl at a distal end of the pawl from the pivot. As illustrated in FIGS. 1A-1C, the pawl 109 and cam arm 108 form a straight arm configuration where both extend in substantially the same direction from the pawljoint 118, with the pawl 109 at one end and the distal portion 11 1 that contacts the cam 104 at the opposite end. The cam and pawl may be arranged in any suitable configuration. For example, the pawl and cam arm may have a bent profile, arcuate profile, or other like design. In another alternative configuration, the pawl and the cam-contacting portion may be positioned on opposite sides of the pivot, creating a see-saw arrangement where movement of the cam-contacting portion in one direction causes the pawl to move in the opposite direction. The pawl joint 118 may be implemented as a pin joint, a ball joint, or other types of pivoting mechanisms. In some cases, the pawl joint 118 may include bearings to reduce friction during pivoting movement. The pawl joint 118 may be designed to allow rotation in a single plane or may allow multi-axial movement depending on the specific application requirements.

[0026] In some implementations, a cam may move the pawl from the engaged position to the disengaged position. For example, the cam 104 may be a snail cam (e.g., as illustrated). For instance, the cam 104 may have a radius that grows around at least a portion of its circumference, forming a spiral or snail-like profile. The cam 104 may include a contact surface at its rim that interacts with the distal portion 111 of the cam arm 108, such that as the cam 104 rotates, the increasing radius of the contact surface may gradually push against the cam arm 108, moving it from the engaged position to the disengaged position.

[0027] Other implementations may use any suitable cam, such as those illustrated with respect to FIGS. 3 or 4. The cam 104 may rotate in one direction, stop, and then rotate in the other direction using a cam stop to determine the extent of rotation. In other examples, the cam 104 may rotate in one direction using position detectors to determine the extent of rotation. For example, the cam 104 may include optical markers that may be detected by optical sensors to determine the rotational position of the cam 104. In some cases, the cam 104 may include magnetic elements that may be detected by hall effect sensors to determine the rotational position of the cam 104. The cam 104 may also include mechanical detents that may interact with mechanical sensors to determine the rotational position of the cam 104.

[0028] In some implementations, a stop member may contact the cam at a rotational extent of the cam corresponding to the pawl in the disengaged position. For example, illustrate an example implementation where the stop member comprises a projection coupled to a cam housing. In the disengaged state shown in FIG. IB, the cam peak 117 of the cam 104 may press against the distal portion 111 of the cam arm 108, causing the pawl 109 to pivot away from the gear 115. Forinstance, this may allow free rotation of the gear 115. The cam peak 117 may be designed with a specific profile to control the rate and timing of disengagement. In some examples, the cam peak 117 may have a gradual slope to provide smooth disengagement or a steeper slope for more rapid disengagement. In some implementations, the distance between the cam peak 117 and the distal portion 111 when fully disengaged may be designed to ensure complete separation between the engagement member 110 and the gear 115.

[0029] The stop member may comprise a projection coupled to a cam housing (e.g., as illustrated in FIGS. 2A-2F), limiting the rotation of the cam 104 at a predetermined position corresponding to full disengagement of the pawl 109. In some implementations, the cam may comprise a cam peak and the stop member may comprise an indentation in a surface that contacts the cam arm proximal to the cam peak (e.g., as illustrated in FIG. 3). The indentation in the surface may provide a detectable position during rotation of the cam 104. In some implementations, a current sensor may detect a current spike responsive to the stop member contacting the cam. The motor 106 may comprise a bi-directional motor configured to reverse the rotation of the cam 104 responsive to the current spike.

[0030] In some implementations, a worm gear arrangement may be coupled between the motor and the cam to transfer rotational motion from the motor to the cam. The rotary lock system 100 may include a worm gear arrangement 101 comprising a worm 102 that may mesh with a worm wheel 103. In some examples, a cam 104 may be coupled to the worm wheel 103. A shaft105 may extend from a motor 106, which may include contacts 107 for electrical connection. In operation, rotation of the motor 106 may drive the shaft 105, which may rotate the worm 102. For instance, the worm 102 may mesh with and drive the worm wheel 103, causing rotation of the cam 104. The cam 104 may interact with the cam arm 108 to control movement of the pawl 109 between engaged and disengaged positions relative to the gear 115. In some implementations, the worm gear arrangement 101 may provide a mechanical advantage that may allow a relatively small motor106 to generate sufficient force to overcome the biasing force of the spring 112. When the motor is deactivated, the biasing element returns the pawl to the engaged position as the cam returns to its initial position.

[0031] FIGS. 2A-2F illustrate various views of motor and cam components for example rotary lock system 100. FIG. 2A shows an exploded front isometric view, FIG. 2B shows an explodedrear isometric view, FIGS. 2C-2D show top views with and without a cover, and FIGS. 2E-2F show cross-sectional views of the rotary lock system 100.

[0032] In some implementations, the cam may move the pawl from the engaged position to the disengaged position. For example, the cam 104 may be rotatably mounted on a cam pivot shaft 202 that extends from the motor housing base 204. In some examples, the cam 104 may be formed with a specific profile, such as a snail cam or eccentric cam shape, designed to provide the desired movement characteristics for the cam arm 108. As the cam 104 rotates, a distal portion 111 of the cam arm 108 may contact the surface of the cam 104. When the cam peak 117 contacts the distal portion 111, the cam arm 108 may pivot about a pawl joint 118, moving the pawl 109 to a disengaged position. As the cam 104 continues to rotate, the cam peak 117 may move away from the distal portion 111, allowing a spring 112 to bias the pawl 109 back towards an engaged position. In some implementations, the distal portion 111 may include a wear-resistant surface or roller to reduce friction with the cam 104. For instance, the distal portion 111 may be coated with a low-friction material such as polytetrafluoroethylene (PTFE) or may incorporate a small bearing or roller element that contacts the cam 104.

[0033] In some implementations, the cam may comprise a cam peak and the stop member may comprise an indentation in a surface that contacts the cam arm proximal to the cam peak. For example, the cam 104 may include a detent or valley in its surface proximal to the cam peak 117. This detent or valley may create a current spike for position detection, rather than using a physical stop. The detent or valley may provide a detectable position during rotation of the cam 104 without requiring contact with a separate stop member. For example, the detent or valley may be formed as a sudden change in the cam profde, creating a momentary reduction in resistance followed by an increase as the cam arm transitions into or out of the detent region. This characteristic pattern in motor current may be detected by monitoring circuitry. In some cases, the depth and profile of the detent or valley may be specifically designed to create a distinctive current signature that can be reliably distinguished from other current variations.

[0034] In some implementations, a worm gear arrangement may be coupled between the motor and the cam to transfer rotational motion from the motor to the cam. For example, the rotary lock system 100 may include a worm gear arrangement 101 coupled between the motor 106 and the cam 104. In some examples, the worm gear arrangement 101 may include a worm 102 coupled to shaft 105 of motor 106. Worm 102 may engage with a worm wheel 103, which may be coupledto the cam 104. The worm 102 may be machined or molded from materials such as hardened steel, brass, or engineering polymers such as polyoxymethylene (POM) or polyamide (nylon). The worm wheel 103 may be formed from similar materials as the worm 102. The worm gear arrangement 101 may provide various gear ratios, such as a gear reduction ratio between 10: 1 and 50: 1, allowing a relatively small motor 106 to generate sufficient torque to overcome the biasing force of a spring 112. In some examples, the worm gear arrangement 101 may also provide self-locking characteristics, preventing back-driving of the mechanism when the motor 106 is not powered.

[0035] In some implementations, a stop member may contact the cam at a rotational extent of the cam corresponding to the pawl in the disengaged position. For example, the cam stop 203 may be integrally formed with the motor housing base 204 as a projection extending into the path of the cam 104. In some implementations, the cam stop 203 may be positioned to contact the cam peak 117 at a specific rotational position corresponding to full disengagement of the pawl 109 from the gear 115. In some cases, the cam stop 203 may be formed from a durable material such as metal or a reinforced polymer to withstand repeated contact with the cam 104. In some implementations, the cam stop 203 may include a cushioning element, such as a rubber or elastomeric pad. In some cases, use of a current spike in the motor may prevent strong impacts to the stop 203 during operation, allowing smaller / thinner cam stops. In other cases, the cam stop 203 may comprise a hard stop that physically prevents motion of the cam 104, arresting rotation of the motor shaft 105 without a current sensor.

[0036] For example, the rotary lock system 100 may include a cam stop 203 extending from the motor housing base 204, such as a projection (e.g., peg, etc.) configured to limit rotation of the cam 104. In some implementations, the cam stop 203 may be positioned to allow various degrees of rotation, such as 180 degrees or 270 degrees, depending on the specific application requirements. When a cam peak 117 of the cam 104 contacts the cam stop 203, the torque on the motor 106 may increase, causing a current spike that can be detected via electrical components, which may cause the motor 106 to stop and reverse direction. In some implementations, the current sensor may be a hall effect sensor, a shunt resistor with an amplifier circuit, or a current transformer that monitors the electrical current flowing to the motor 106. In some implementations, the current sensor may be implemented using a small-value resistor in series with the motor power supply, with an amplifier circuit to measure the voltage drop across the resistor, or integrated into a motor driver integrated circuit (IC) that provides both power control and current monitoring functions.For instance, the control system may include a microcontroller or dedicated logic circuit that processes the current sensor signal with specific current thresholds and timing parameters to accurately detect position-related current spikes while ignoring normal operational current variations.

[0037] In some implementations, the motor may comprise a bi-directional motor configured to reverse the rotation of the cam responsive to the current spike. For example, the rotary lock system 100 may include a motor 106 mounted within the motor housing. In some examples, the motor 106 may be a direct current (DC) motor, a stepper motor, or another type of electric motor. In some examples, the motor 106 may include a gearbox to provide the appropriate torque and speed characteristics. The motor 106 may be controlled by a microcontroller or other control circuitry that may monitor the position of the cam 104 and control the rotation of the motor 106 accordingly. In some cases, the motor 106 may be a bidirectional motor capable of rotating in both clockwise and counterclockwise directions. The motor 106 may include contacts 107 for electrical connection. For instance, first contact wire 214 and second contact wire 213 may provide electrical connections 212 to power the motor 106. In some implementations, the motor housing base 204 may include conductive connector prongs 215, such as a first connector prong 217 and a second connector prong 218, for external electrical connectivity.

[0038] In some implementations, the motor may be configured to reverse the rotation of the cam responsive to a current spike. For example, the motor 106 may include a shaft 105 extending from one end. In various examples, the shaft 105 may be formed from hardened steel or stainless steel to withstand torque and wear during operation. In some implementations, the motor 106 may be a bidirectional motor. Upon detecting the current spike, the control system may reverse the direction of the motor 106, causing the cam 104 to rotate in the opposite direction. This bidirectional capability may allow the rotary lock system 100 to quickly transition between engaged and disengaged states without requiring a full rotation of the cam 104. For example, the motor 106 may be a brushed DC motor with an H-bridge driver circuit that allows voltage polarity reversal for direction control. Alternatively, the motor 106 may be a brushless DC motor with electronic commutation that can be controlled to run in either direction. In some cases, the control system may implement a brief delay or braking period between direction changes to prevent excessive current draw during reversal.

[0039] In some implementations, the rotary lock system 100 may include a motor housing comprising a motor housing base 204 and a motor housing cover 205, which may be formed from durable plastic material or metals such as aluminum or steel to enclose internal components. In some examples, the motor housing base 204 may include alignment holes 210, 211 configured to receive alignment pegs 208, 209 with tapped holes 216 for securing the system to a mounting surface, while the motor housing cover 205 may include housing retainment detents 206 that engage with housing retainment clips 207 on the motor housing base 204. For example, the alignment pegs 208, 209 may be coupled to various vehicle components such as a brake caliper assembly, a mounting flange for positioning the rotary lock system relative to a gear, or a fixed structure on a vehicle frame.

[0040] FIG. 3 illustrates an isometric view of cam and motor components for an example rotary lock system as an alternative implementation to the worm gear arrangement shown in FIGS. 2A-2E. In some implementations, the helical cam 301 may replace the worm gear arrangement 101 and cam 104 of the rotary lock system 100 shown in FIG. 1A, while maintaining the same functional relationship with the cam arm 108 and pawl 109. For example, the helical contact surface 302 of the helical cam 301 may interact with the distal portion 111 of the cam arm 108 to move the pawl 109 between engaged and disengaged positions relative to the gear 115. The motor 308 may drive rotation of the helical cam 301 through the shaft 306, similar to how motor 106 drives rotation of the cam 104 through the worm gear arrangement 101 in FIGS. 1 A-1C. In some implementations, the detent 303 may provide a detectable position during rotation of the helical cam 301, allowing for precise control of the pawl 109 position through current spike detection, while the cam hard stop 304 and hard stop detent 305 may limit the rotational range of the helical cam 301. Unless context indicates otherwise, any undescribed aspects of the implementation of FIG. 3 may be implemented as described with respect to corresponding aspects of FIGS. 1A-2E.

[0041] In some implementations, the rotary lock system may include a helical cam 301 positioned adjacent to the motor housing 309. The helical cam 301 may include a helical contact surface 302 that may wrap around the cam. For example, the helical contact surface 302 may comprise a continuous spiral groove or ridge that extends around the circumference of the helical cam 301. In some cases, the helical contact surface 302 may have a constant pitch, while in other cases, the pitch may vary along the length of the helical cam 301 to provide different rates of movement at different rotational positions. The helical contact surface 302 may be machined frommaterials such as hardened steel or stainless steel. In some implementations, the helical contact surface 302 may be coated with a wear-resistant material to enhance durability during operation.

[0042] The helical cam 301 may include a detent 303 formed in its surface proximal to a peak 307. For instance, the detent 303 may comprise an indentation or a bump on the helical contact surface 302. The detent 303 may provide a detectable position during rotation of the helical cam 301. In some implementations, the detent 303 may cause a slight variation in the motor torque, generating a detectable current spike that may be used to arrest rotation of the helical cam 301. The detent 303 may be formed with various depths and profiles depending on the sensitivity of the current detection system. For example, the detent 303 may have a depth between 0.5 mm and 2 mm, or between 0.5 mm and 1 mm. In some cases, the detent 303 may have a gradual entry slope and a steeper exit slope to create a distinctive current signature during operation. In other implementations, the motor housing may comprise a cam stop as described above. In such implementations contact between peak 307 and the cam stop may cause a current spike used to stop rotation of the motor, as described above.

[0043] In some cases, the helical cam 301 may include a cam hard stop 304 that may interact with a hard stop detent 305 to limit rotation of the cam in the engaged state. For example, the cam hard stop 304 may comprise a protrusion or tab on the helical cam 301, while the hard stop detent 305 may be a corresponding recess or surface on a fixed portion of the rotary lock system. The hard stop detent 305 may arrest the rotation of the helical cam 301 in the engagement direction. The cam hard stop 304 may be integrally formed with the helical cam 301 or may be a separate component attached to the helical cam 301. In some implementations, the cam hard stop 304 may be formed from a durable material such as hardened steel or stainless steel to withstand repeated contact with the hard stop detent 305. The hard stop detent 305 may include a cushioning element, such as a high-durometer elastomeric pad, to reduce impact forces and noise during operation.

[0044] The peak 307 may extend from one end of the helical cam 301. For instance, the peak 307 may be the highest point of the helical contact surface 302, providing maximum displacement of a cam arm that may interact with the helical cam 301. The peak 307 may have various profiles depending on the desired movement characteristics of the cam arm. In some implementations, the peak 307 may have a rounded profile to provide smooth transitions during engagement and disengagement operations. In other implementations, the peak 307 may have a more angular profile to provide rapid transitions between engaged and disengaged states. The height of the peak307 relative to the base diameter of the helical cam 301 may be designed to provide sufficient displacement of the cam arm to ensure complete disengagement of a pawl from a gear. In some implementations, the helical cam 301 may be formed from metals such as hardened steel, stainless steel, or high-strength aluminum alloys.

[0045] In some implementations, the motor 308 may drive rotation of the helical cam 301 through the shaft 306 to control the position of a pawl. For example, as the helical cam 301 rotates, the helical contact surface 302 may interact with a cam arm, moving the cam arm between engaged and disengaged positions. The detent 303 may provide a detectable position during rotation of the helical cam 301, which may create a current spike as described above. The motor 308 may be a direct current motor, a stepper motor, or another type of electric motor. As described above, the motor 308 may be controlled by a microcontroller or other control circuitry that may monitor the position of the helical cam 301 and control the rotation of the motor 308 accordingly.

[0046] The arrangement of these components may allow the helical cam 301 to rotate through a defined range of motion to control engagement and disengagement of a pawl with a gear. For example, as the helical cam 301 rotates, the helical contact surface 302 may push against a cam arm, causing the cam arm to pivot and move a connected pawl between engaged and disengaged positions relative to a gear. The rotational range of the helical cam 301 may be designed to provide sufficient movement of the pawl while minimizing motor travel. In some implementations, the rotational range may be between 90 degrees and 270 degrees, or between 120 degrees and 180 degrees, depending on the specific application requirements and the profile of the helical contact surface 302.

[0047] FIG. 4 illustrates an isometric view of a motor and cam assembly for an example rotary lock system. In some implementations, the assembly shown in FIG. 4 may replace the worm gear arrangement 101 illustrated in FIG. 1A, while maintaining the same functional relationship with the cam arm 108 and pawl 109. For example, the cam 407 may interact with the distal portion 111 of the cam arm 108 to move the pawl 109 between engaged and disengaged positions relative to the gear 115. The motor 406 may drive rotation of the cam 407 through the bevel gear arrangement 401, similar to how motor 106 drives rotation of the cam 104 through the worm gear arrangement 101 in FIGS. 1A-1C.

[0048] In some implementations, the rotary lock system may include a bevel gear arrangement 401. For example, the bevel gear arrangement 401 may comprise a pinion gear 402 that meshes with a cam gear 403. The pinion gear 402 may be directly coupled to the shaft 404 extending from the motor 406, while the cam gear 403 may be mounted perpendicular to the pinion gear 402. In some cases, the pinion gear 402 and cam gear 403 may be made from hardened steel, brass, or engineering polymers such as polyoxymethylene (POM) or polyamide (nylon). The bevel gear arrangement 401 may provide various gear ratios, such as a gear reduction ratio between 5: 1 and 20: 1. In some implementations, the bevel gear arrangement 401 may have a constant pitch, while in other cases, the pitch may vary along the gear teeth to provide different rates of movement at different rotational positions. The bevel gear arrangement 401 may enable conversion of rotational motion between intersecting axes through the meshing of the pinion gear 402 with the cam gear 403, allowing for more compact packaging of the rotary lock system components compared to the worm gear arrangement 101.

[0049] In some implementations, a shaft 404 may extend through a motor housing 405. For instance, the shaft 404 may be coupled to a motor 406 contained within the motor housing 405. The shaft 404 may be formed from hardened steel or stainless steel to withstand torque and wear during operation. The motor 406 may be a direct current (DC) motor, a stepper motor, or another type of electric motor. In some examples, the motor 406 may be a brushed DC motor with an H- bridge driver circuit that allows voltage polarity reversal for direction control. Alternatively, the motor 406 may be a brushless DC motor with electronic commutation that can be controlled to run in either direction. In some cases, the motor 406 may include a gearbox to provide appropriate torque and speed characteristics. The motor housing 405 may be formed from durable plastic material or metals such as aluminum or steel to enclose and protect the motor 406 and associated components. In some implementations, the motor housing 405 may include mounting features similar to those described for motor housing base 204, such as alignment holes and tapped holes for securing the system to a mounting surface.

[0050] In some implementations, a cam 407 may be positioned adjacent to the motor housing 405. For example, the cam 407 may be mounted to the cam gear 403, forming an alternative snail cam arrangement. The cam 407 may be machined from materials such as hardened steel or stainless steel. In some implementations, the cam 407 may be coated with a wear-resistant material to enhance durability during operation. The cam 407 may include a cam nose 408 that extends fromits surface. The cam nose 408 may be the highest point of the cam 407, providing maximum displacement of a cam arm that may interact with the cam 407. In some cases, the cam nose 408 may be designed with a specific profile to control the rate and timing of pawl disengagement. For instance, the cam nose 408 may have a gradual slope to provide smooth disengagement or a steeper slope for more rapid disengagement. The height of the cam nose 408 relative to the base diameter of the cam 407 may be designed to provide sufficient displacement of the cam arm to ensure complete disengagement of a pawl from a gear.

[0051] In some implementations, the cam 407 may feature an indent 409 formed into its profile. For example, the indent 409 may serve a similar function to the detent 303 described in relation to FIG. 3, providing a detectable position during rotation of the cam 407. The indent 409 may comprise an indentation or a bump on the surface of cam 407. In some cases, the indent 409 may cause a slight variation in the motor torque, generating a detectable current spike that may be used to determine the rotational position of the cam 407. The indent 409 may be formed with various depths and profiles depending on the sensitivity of the current detection system. For example, the indent 409 may have a depth between 0.5 mm and 2 mm, or between 0.5 mm and 1 mm. In some cases, the indent 409 may have a gradual entry slope and a steeper exit slope to create a distinctive current signature during operation.

[0052] During operation of the rotary lock system, the motor 406 may drive rotation of the pinion gear 402 through the shaft 404. The rotation of the pinion gear 402 may in turn rotate the cam gear 403 and the attached cam 407. As the cam 407 rotates, the cam nose 408 may interact with a cam arm (not shown in FIG. 4) in a manner similar to the interaction between the cam 104 and the cam arm 108 described in relation to FIGS. 1A-1C. This interaction may control the movement of a pawl between engaged and disengaged positions relative to a gear. The rotational range of the cam 407 may be designed to provide sufficient movement of the pawl while minimizing the required motor travel. In some implementations, the rotational range may be between 90 degrees and 270 degrees, or between 120 degrees and 180 degrees, depending on the specific application requirements and the profile of the cam 407. In some implementations, the cam 407 may include a hard stop feature similar to the cam hard stop 304 described in relation to FIG. 3, which may limit the rotational range of the cam 407.

[0053] In some implementations, the indent 409 and cam nose 408 on the cam 407 may provide features for controlling movement and position detection during operation. For example,as the cam 407 rotates and the indent 409 passes a certain point, it may create a detectable change in the motor current. This change may be used by a control system to determine the rotational position of the cam 407 and, by extension, the position of the pawl. The current sensor may be a hall effect sensor, a shunt resistor with an amplifier circuit, or a current transformer that monitors the electrical current flowing to the motor 406. In some implementations, the current sensor may be implemented using a small-value resistor in series with the motor power supply, with an amplifier circuit to measure the voltage drop across the resistor, or integrated into a motor driver integrated circuit (IC) that provides both power control and current monitoring functions. The control system may include a microcontroller or dedicated logic circuit that processes the current sensor signal with specific current thresholds and timing parameters to accurately detect position- related current spikes while ignoring normal operational current variations.

[0054] FIG. 5 illustrates a block diagram of a brake system implemented in a vehicle 500. The vehicle 500 may include a human machine interface 501 that communicates with a control unit 502. In some implementations, the control unit 502 may comprise a processor executing instructions stored on a non-transitory computer-readable medium to control operation of the brake system components. For example, the control unit 502 may include a microprocessor, memory, and input / output interfaces for communicating with and controlling other system components. In some cases, the control unit 502 may include a digital signal processor (DSP), a field- programmable gate array (FPGA), or an application-specific integrated circuit (ASIC). The control unit 502 may be configured with various communication protocols such as controller area network (CAN), local interconnect network (LIN), or ethemet to interface with other vehicle systems.

[0055] In some implementations, the brake system may include a current sensor 503 that connects to a motor 504. The motor 504 may operate in conjunction with a brake 505, which may interface with a brake actuator 506. For example, the motor 504 and brake actuator 506 may be implemented as a rotary lock system, such as those described with respect to FIGS. 1A-3. For instance, the brake actuator 506 may include a pawl, cam arm, cam, and biasing element arranged as described previously to selectively engage and disengage the brake 505. In some cases, the brake 505 may be a disc brake, drum brake, or caliper brake for a vehicle wheel. The brake actuator 506 may include a gear coupled to a brake application mechanism that converts rotational motion into linear motion for applying brake pressure. In some implementations, the brake 505 may be aparking brake that maintains vehicle position when stationary, or an emergency brake that provides redundant braking capability.

[0056] In some implementations, the current sensor 503 may be configured to detect a current spike in the motor 504 responsive to a cam engaging with a stopping member of the brake actuator 506. Upon detecting a current spike, the current sensor 503 may provide a signal to the control unit 502. In some implementations, the current sensor 503 may be integrated with the control unit 502 as part of a motor driver circuit. For example, the current sensor 503 may include a hall effect sensor, a shunt resistor with an amplifier circuit, or a current transformer that monitors the electrical current flowing to the motor 504. In some cases, the current sensor 503 may be implemented using a small-value resistor in series with the motor power supply, with an amplifier circuit to measure the voltage drop across the resistor. Alternatively, the current sensor 503 may be integrated into a motor driver integrated circuit that provides both power control and current monitoring functions. The current sensor 503 may include filtering components to distinguish between normal operational current variations and position-related current spikes.

[0057] In some implementations, the current sensor 503 may include circuitry to reverse the motor 504 responsive to the current spike. This circuitry may be implemented as part of the control unit 502 or as a separate component. For example, the control unit 502 may control the motor direction by adjusting the voltage polarity provided to the motor 504. For instance, the control unit502 may include an H-bridge driver circuit that allows voltage polarity reversal for bidirectional control of the motor 504. In some cases, the control unit 502 may implement a brief delay or braking period between direction changes to prevent excessive current draw during reversal. The control circuitry may include protective features such as current limiting, thermal shutdown, or short-circuit protection to safeguard the motor 504 and associated electronics. In some implementations, the control unit 502 may include pulse-width modulation (PWM) capabilities to control motor speed during engagement and disengagement operations.

[0058] In some implementations, the control unit 502 may receive input signals from the human machine interface 501 and coordinate the operation of the brake system components based on these inputs and feedback from the current sensor 503. For example, the control unit 502 may activate the motor 504 to engage or disengage the brake 505 via the brake actuator 506 in response to user input from the human machine interface 501, while using feedback from the current sensor503 to determine when the brake actuator 506 has reached its engaged or disengaged position. Thehuman machine interface 501 may include various input devices such as buttons, switches, levers, touch screens, etc., that allow a user to control the brake system. In some cases, the human machine interface 501 may include visual, auditory, or haptic feedback elements to indicate the status of the brake system to the user.

[0059] In some implementations, devices or systems disclosed herein can be utilized, manufactured, or installed using methods embodying aspects of the invention. Correspondingly, any description herein of particular features, capabilities, or intended purposes of a device or system is generally intended to include disclosure of a method of using such devices for the intended purposes, a method of otherwise implementing such capabilities, a method of manufacturing relevant components of such a device or system (or the device or system as a whole), and a method of installing disclosed (or otherwise known) components to support such purposes or capabilities. Similarly, unless otherwise indicated or limited, discussion herein of any method of manufacturing or using for a particular device or system, including installing the device or system, is intended to inherently include disclosure, as embodiments of the invention, of the utilized features and implemented capabilities of such device or system.

[0060] As used herein, the term "coupled" may refer to a connection between two or more components or elements. The connection may be direct, indirect, integral, or the like. In a direct connection, the components may be physically attached to each other without intervening elements. In an indirect connection, the components may be connected through one or more intermediate elements or structures. In an integral connection, the components may be formed as a single, unitary piece. For example, in some implementations, a pawl may be coupled to a cam arm by being integrally formed as a single part. In other implementations, the pawl may be coupled to the cam arm as a separate component, either directly attached or indirectly connected through intermediate elements. The term "coupled" may encompass various types of mechanical, electrical, or magnetic connections, and may include fixed or detachable couplings, as allowed by context.

[0061] Also as used herein, unless otherwise limited or defined, “or” indicates a non-exclusive list of components or operations that can be present in any variety of combinations, rather than an exclusive list of components that can be present only as alternatives to each other. For example, a list of “A, B, or C” indicates options of: A; B; C; A and B; A and C; B and C; and A, B, and C. Correspondingly, the term “or” as used herein is intended to indicate exclusive alternatives only when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly oneof.” For example, a list of “one of A, B, or C” indicates options of A, but not B and C; B, but not A and C; and C, but not A and B. A list preceded by “one or more” (and variations thereon) and including “or” to separate listed elements indicates options of one or more of any or all of the listed elements. For example, the phrases “one or more of A, B, or C” and “at least one of A, B, or C” indicate options of: one or more A; one or more B; one or more C; one or more A and one or more B; one or more B and one or more C; one or more A and one or more C; and one or more of A, one or more of B, and one or more of C. Similarly, a list preceded by “a plurality of’ (and variations thereon) and including “or” to separate listed elements indicates options of multiple instances of any or all of the listed elements. For example, the phrases “a plurality of A, B, or C” and “two or more of A, B, or C” indicate options of: A and B; B and C; A and C; and A, B, and C.

[0062] As used herein, unless otherwise defined or limited, directional terms are used for convenience of reference for discussion of particular figures or examples. For example, references to downward (or other) directions or top (or other) positions may be used to discuss aspects of a particular example or figure, but do not necessarily require similar orientation or geometry in all installations or configurations.

[0063] Also as used herein, unless otherwise limited or defined, “substantially parallel” indicates a direction that is within ± 12 degrees of a reference direction (e.g., within ± 6 degrees), inclusive. Also as used herein, unless otherwise limited or defined, “substantially perpendicular” indicates a direction that is within ± 12 degrees of perpendicular a reference direction (e.g., within ± 6 degrees), inclusive.

[0064] Also as used herein, unless otherwise limited or defined, “integral” and derivatives thereof (e.g., “integrally”) describe elements that are manufactured as a single piece without fasteners, adhesive, or the like to secure separate components together. For example, an element stamped, cast, or otherwise molded as a single-piece component from a single piece of sheet metal or using a single mold, without rivets, screws, or adhesive to hold separately formed pieces together is an integral (and integrally formed) element. In contrast, an element formed from multiple pieces that are separately formed initially then later connected together, is not an integral (or integrally formed) element.

[0065] Additionally, unless otherwise specified or limited, the terms “about” and “approximately,” as used herein with respect to a reference value, refer to variations from thereference value of ± 15% or less, inclusive of the endpoints of the range. Similarly, the term “substantially equal” (and the like) as used herein with respect to a reference value refers to variations from the reference value of less than ± 10%, inclusive. Where specified, “substantially” can indicate in particular a variation in one numerical direction relative to a reference value. For example, “substantially less” than a reference value (and the like) indicates a value that is reduced from the reference value by 10% or more, and “substantially more” than a reference value (and the like) indicates a value that is increased from the reference value by 10% or more.

[0066] Also as used herein, unless otherwise limited or specified, “substantially identical” refers to two or more components or systems that are manufactured or used according to the same process and specification, with variation between the components or systems that are within the limitations of acceptable tolerances for the relevant process and specification. For example, two components can be considered to be substantially identical if the components are manufactured according to the same standardized manufacturing steps, with the same materials, and within the same acceptable dimensional tolerances (e.g., as specified for a particular process or product).

[0067] Unless otherwise specifically indicated, ordinal numbers are used herein for convenience of reference, based generally on the order in which particular components are presented in the relevant part of the disclosure. In this regard, for example, designations such as “first,” “second,” etc., generally indicate only the order in which a thus-labeled component is introduced for discussion and generally do not indicate or require a particular spatial, functional, temporal, or structural primacy or order.

[0068] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Given the benefit of this disclosure, various modifications to these embodiments will be readily apparent to those skilled in the art, and the principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0069] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

Claims

CLAIMS1. A device, comprising: a pawl pivotably coupled to a pivot to move between an engaged position and a disengaged position relative to a gear; a cam arm rigidly coupled to the pawl; a cam to move the pawl from the engaged position to the disengaged position; a motor to rotate the cam to move the pawl from the engaged position to the disengaged position; and a biasing element coupled to the pawl to move the pawl from the disengaged position to the engaged position.

2. The device of any of claim 1, wherein the pawl comprises an engagement member having a first surface to engage with teeth of the gear to arrest rotation of the gear in a first direction and a second surface to engage with the teeth of the gear to allow ratcheting rotation of the gear in a second direction.

3. The device of any of claims 1-2, wherein the cam arm is coupled to the pawl at a distal end of the pawl from the pivot.

4. The device of any of claims 1-3, further comprising a worm gear arrangement coupled between the motor and the cam to transfer rotational motion from the motor to the cam.

5. The device of any of claims 1-4, further comprising a stop member to contact the cam at a rotational extent of the cam corresponding to the pawl in the disengaged position.

6. The device of any of claims 1-5, wherein the stop member comprises a projection coupled to a cam housing.

7. The device of any of claims 1-5, wherein the cam comprises a cam peak and the stop member comprises an indentation in a surface that contacts the cam arm proximal to the cam peak.

8. The device of any of claims 1-7, further comprising a current sensor to detect a current spike responsive to the stop member contacting the cam.

9. The device of any of claims 1-8, wherein the motor comprises a bi-directional motor configured to reverse the rotation of the cam responsive to the current spike.

10. A method of operating a device, comprising: pivoting a pawl coupled to a pivot to move between an engaged position and a disengaged position relative to a gear; rotating, using a motor, a cam to engage a cam arm rigidly coupled to the pawl to move the pawl from the engaged position to the disengaged position; and biasing the pawl via a spring member to move the pawl from the disengaged position to the engaged position.

11. The method of any of claim 10, wherein the pawl comprises an engagement member having a first surface to engage with teeth of the gear to arrest rotation of the gear in a first direction and a second surface to engage with the teeth of the gear to allow ratcheting rotation of the gear in a second direction.

12. The method of any of claims 10-11, further comprising contacting the cam with a stop member at a rotational extent of the cam.

13. The method of any of claims 10-12, wherein the stop member comprises a projection coupled to a cam housing.

14. The method of any of claims 10-12, wherein the cam comprises a cam peak and the stop member comprises an indentation in a surface that contacts the cam arm proximal to the cam peak.

15. The method of any of claims 10-14, further comprising detecting, with a current sensor, a current spike responsive to the stop member contacting the cam.

16. A brake system, comprising: a gear; a brake coupled to the gear; a pawl pivotably coupled to a pivot to move between an engaged position and a disengaged position relative to the gear; a cam arm rigidly coupled to the pawl; a cam to move the pawl from the engaged position to the disengaged position; a motor to rotate the cam to move the pawl from the engaged position to the disengaged position; and a biasing element coupled to the pawl to move the pawl from the disengaged position to the engaged position.

17. The brake system of any of claim 16, wherein the pawl comprises an engagement member having a first surface to engage with teeth of the gear to arrest rotation of the gear in a first direction and a second surface to engage with the teeth of the gear to allow ratcheting rotation of the gear in a second direction.

18. The brake system of any of claims 16-17, wherein the cam arm is coupled to the pawl at a distal end of the pawl from the pivot.

19. The brake system of any of claims 16-18, further comprising a worm gear arrangement coupled between the motor and the cam to transfer rotational motion from the motor to the cam.

20. The brake system of any of claims 16-19, further comprising a stop member and a current sensor to detect a current spike responsive to the stop member contacting the cam.

21. The brake system of any of claims 16-20, wherein the stop member comprises a projection coupled to a cam housing.

22. The brake system of any of claims 16-20, wherein the cam comprises a cam peak and the stop member comprises an indentation in a surface that contacts the cam arm proximal to the cam peak.

23. The brake system of any of claims 16-22, wherein the brake comprises a parking brake for a vehicle.

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