Manual override and locking mechanism and actuator including same

ES 2 269 846 T3

DESCRIPTION

Manual correction and locking mechanism, and actuator that includes them.

The present invention relates generally to motor-actuated reversible actuators, and more specifically to mechanisms that allow manual setting of the position of motor-actuated, reversible actuators.

Motor-actuated actuator mechanisms, to be used in controlling the position of valves, dampers, etc., typically include a motor that drives an output coupling in one direction, through a gear train, to position the valve, the damper , etc., in a desired position. Spring-type, or fail-safe, actuator mechanisms also typically include a torsion spring coupled to the gear train, which is wound during motor drive. In this way, the energy to turn the shaft in the other direction, when the motor is no longer excited, is stored in the spring. Upon loss of power to the engine, the torsion spring unwinds, leading the gear train to position the valve, damper, etc., in a desired, fail-safe position. Such actuating mechanisms are described in US Patent No. 5 310 023, entitled Motor-Driven, Spring-Returned Rotary Actuator, and in US Patent No. 5 595 081, entitled Rotary Actuator With Spring Return, which are both assigned to the assignee of this application, the teachings and disclosures of which are incorporated herein in their entirety, by reference.

In such rotary actuators, the motor rotates the output shaft and winds a spring, by means of a gear train that substantially reduces the speed, and substantially amplifies the torque, of the motor. When the spring is unwound to rotate the output shaft, the spring acts in reverse through a gear train, and drives the motor shaft back. Such an actuator is frequently used to drive a utilization device, such as a damper in the conduit of a heating, ventilation and cooling system. When the motor stops being excited, the spring biases the output shaft in a direction that moves the damper to a closed position, against a fixed stop. The effectiveness of the damper sealing against this fixed stop is to some extent a function of the amount of spring force that remains on the torsion spring when the damper hits the stop. If this position is reached when the spring has released all of its stored energy, the quality of the seal against the stop is determined exclusively by the quiescent mechanical contact between these two surfaces, taking into account the mechanical connection to the motor through the drive train. gears.

While such contact between the damper and fixed stop may be adequate to stop the flow through the damper for many installations, certain installations may require that the seal between the damper and the stop be positively supported. That is, there are some installations that need the damper to be able to remain positively closed with increased pressure. Such positive closing force against the fixed stop is especially desirable in high pressure installations and valve operations. Certainly, almost all installations could benefit from such a positive closing force, imparted by the spring, to ensure the integrity of the closed position.

To provide such positive closing force on the damper, valve, etc., driven by the spring return actuator, the actuator output coupling is often rotated a few degrees, before being connected to the drive shaft of the driver. (for example damper, valve, etc.). Such rotation of the output coupling winds the spring, to establish a preload. Once a spring preload has been established, the actuator output coupling is connected to the drive shaft of the driven device which is positioned in its closed or safety position (here referred to as the zero position). Once connected, the spring imparts the positive preload force to the driven device, in its zero position.

Unfortunately, since the actuator output coupling is coupled through a torque multiplier gear train, hand rotation of this output coupling is somewhat difficult. In addition, since the return spring also acts through the torque multiplier gear train, keeping the output coupling in the preload position, while attempting to connect this output coupling to the drive shaft of the driven device, it is also quite difficult.

In view of the foregoing, the present invention is directed to a new and improved rotary actuator that includes a manual override that allows a preload to be imparted on a return spring simply and efficiently. Furthermore, the invention is directed to a new and improved rotary actuator, having such a manual override, including a locking mechanism capable of locking the output coupling, against rotation under the influence of a return spring.

A rotary actuator according to one embodiment of the present invention comprises a motor, a gear train, and an output coupling driven by the motor through the gear train. The gear train multiplies the motor torque to drive the output coupling. Also included is a manual correction mechanism that has an accessible user interface. The manual correction mechanism works in conjunction with the gear train, to allow manual positioning of the output coupling. In addition, a manual locking mechanism is also included, which has an accessible user interface. This manual locking mechanism engages the gear train, to prevent rotation of the output coupling in a first direction.

Preferably, the actuator further comprises a spring return mechanism, including a torsion spring coupled to the gear train. This torsion spring is wound after the excitation of the motor that drives the output coupling, in a second direction, and is unwound after the motor excitation ceases to drive the output coupling through a part of the drive gear train, in the first sense. The manual correction mechanism is coupled through the torsion spring, so that the operation of the manual correction to effect a rotation of the

ES 2 269 846 T3 output coupling in the second direction, winds the torsion spring. In a preferred embodiment, the manual locking mechanism includes a segment gear head, having a toothed portion and a smooth portion, on its face. The gear segment head is rotatable, between a locked position, in which the toothed portion engages the gear train preventing rotation of the output coupling in the first direction, and an unlocked position, in which the smooth portion is positioned in association with the gear train, and the toothed portion is decoupled from the gear train.

In addition, the manual locking mechanism preferably includes a locking reset spring, operatively coupled to the gear segment head, to bias the gear segment head to an unlocked position. The gear segment head further includes a slot adapted to receive a stop pin. This stopper pin abuts against a first end of the slot in the unlocked position, and against a second end of the slot in the locked position. Rotation at a point of engagement, with the gear train lock mechanism, under the influence of the torsion spring, is in the direction that the gear segment head rotates against the force of the lock reset spring. This keeps the manual locking mechanism in the closed position. Rotation at a point of engagement with the gear train lock mechanism, under the influence of the motor, is in the direction that the gear segment head rotates, according to the force of the lock reset spring. This helps the manual locking mechanism to achieve the unlocked position. Preferably, the motor drives the output coupling in a second direction, to disengage the locking mechanism from the gear train, to allow rotation of the output coupling in the first direction.

In an alternative embodiment of the present invention, a locking mechanism for a motor-driven rotary actuator, having a gear train that drivenly couples a motor, is provided to an output coupling to drive a device. This locking mechanism comprises a segment gear head, having a toothed portion and a smooth portion, on its face. The toothed portion is configured to engage a gear, in the gear train. The gear segment head is positioned relative to the gear, such that rotation of the gear segment head, between a locked position and an unlocked position, results in the engagement of the toothed portion with the gear, in the locked position, and disengagement of the toothed portion in the unlocked position. The gear segment head further includes a slot, adapted to accommodate a stopper pin, and is positioned in the gear segment head such that the stopper pin is recessed against a first end of the slot in the unlocked position. , and against a second end of the slot in the locked position. A locking initialization spring is operatively coupled with the gear segment head to bias the gear segment head to an unlocked position. In addition, there is a user interface coupled to the gear segment head to rotate the gear segment head between the locked and unlocked positions.

In a preferred embodiment, the toothed portion of the gear segment head occupies approximately 25 °. Furthermore, the toothed portion is preferably positioned, relative to the segment, such that the rotation of the gear train, at a point of engagement with the locking mechanism, is in a direction to rotate the gear segment head, so that the stopper pin engages the second end. Additionally, the lock reset spring is preferably positioned so that engagement of the toothed portion of the gear segment head with the gear train, when the actuator is driving the device to a closed position, results in the rotation of the gear segment head, against the bypass applied by the lock reset spring.

In another alternative embodiment of the present invention, a spring return, motor driven rotary actuator is provided to drive a flow control device to an open position when activated, and to a closed position upon loss of power. This actuator comprises a motor, a torque multiplier gear train, speed reducer, driven coupled to an output of the motor, and an output coupling driven gear train. This output coupling is driven, in a first sense, by the motor. A spring return mechanism is also included, which includes a torsion spring coupled to the gear train. The torsion spring is wound upon excitation of the motor driving the output coupling in the first direction, and unwinds upon removal of the motor actuation, to drive the output coupling through the drive gear train, in a second sense. A manual correction mechanism is provided, having a first user accessible interface, which works in conjunction with the spring return mechanism, to allow manual positioning of the output coupling, and winding of the torsion spring. Finally, a manual locking mechanism is also provided, which has a second user-accessible interface. This manual locking mechanism locks the gear train to prevent rotation of the output coupling in the second direction.

In one embodiment, the manual locking mechanism includes a gear segment head, which has a toothed portion on its face, and is rotatable between a locked position, in which the toothed portion engages the gear train preventing rotation of the gear. output engagement in the second direction, and an unlocked position, in which the toothed portion is disengaged from the gear train. The manual locking mechanism further includes a locking reset spring, operatively coupled to the gear segment head, to bias the gear segment head to the unlocked position. Additionally, the gear segment head includes a slot, adapted to accommodate a stop pin, which is recessed against a first end of the slot in the locked position, to prevent any further rotation of the gear segment head. In addition, the rotation of the gear train in

ES 2 269 846 T3 a point of engagement with the locking mechanism, under the influence of the torsion spring, is in the direction by rotating the gear segment head against the force of the locking reset spring, thereby maintaining the manual locking mechanism in the locked position. The rotation of the gear train at this point of engagement with the locking mechanism, under the influence of the motor, is in one direction by rotating the gear segment head according to the force of the locking reset spring, assisting thereby mode to the manual locking mechanism, to achieve the unlocked position. Preferably, the motor drives the output coupling in the first direction, to disengage the locking mechanism from the gear train, to allow rotation of the output coupling in the second direction.

From the following detailed description, taken in conjunction with the accompanying drawings, other features and advantages of the invention will become more apparent.

The accompanying drawings incorporated, and forming part of the specification, illustrate various aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:

Figure 1 is a simplified perspective view of a spring return rotary actuator, constructed in accordance with the teachings of the present invention, installed to drive a damper, for use in the duct of a heating, ventilation system and refrigeration (HVAC);

Figure 2 is a simplified perspective view of the actuator of Figure 1, enlarged to show details of the interface for the manual locking and correction mechanisms of the present invention;

Figure 3 is a detailed, simplified view of the interior of an actuator constructed in accordance with the teachings of the present invention;

Figure 4 is a perspective view of the actuator gear train arrangement of Figure 3;

Figure 5 is an isolated perspective view of one embodiment of the locking mechanism of the present invention, in an unlocked position; and Figure 6 is an isolated perspective view of the locking mechanism of Figure 5 in a locked position.

While the invention will be described in relation to certain preferred embodiments, it is not intended to be limited to these embodiments. Rather, it is intended to cover all alternatives, modifications, and equivalents that are included within the spirit and scope of the invention, as defined by the appended claims.

As illustrated in FIG. 1, an embodiment of the present invention is performed on a reversible rotary actuator 10, to control the position of a utilization device 12. In this exemplary embodiment, the utilization device 12 is shown having a damper located in a heating, ventilation and air conditioning (HVAC) conduit 16, and is shown mounted on a shaft 14, to rotate through approximately 90 degrees, between a fully closed vertical position and a fully open horizontal position. In this embodiment, the damper is closed and open when shaft 14 is rotated clockwise and counterclockwise, respectively. When the damper reaches its fully closed position, it strikes against a fixed stop 18, which is shown schematically in Figure 1 being located within the conduit 16.

As can be seen from the exploded view of the actuator 10 of the present invention, illustrated in FIG. 2, the housing 20 of the actuator 10 includes a manual correction interface 22, adapted to receive a spring winding tool 24. By means of the Using this tool, a user can wind the torsion spring that returns the output coupling 26 of the actuator 10 to its zero position, once power is removed to the motor. As discussed above, winding the torsion spring stores energy in the spring, which can be applied with a preload, once the output shaft 14 (see Figure 1) is engaged with the output coupling 26. A Once the preload has been applied to the spring, the user can manually lock the actuator 10 via interface 28, to prevent the spring from returning to its quiescent state. Once locked in position, the damper 12 is located in its zero position and its output shaft 14 is coupled to the output coupling 26 of the actuator 10. The user can then unlock the actuator 10, by moving the locking interface 28 to its unlocked position, or it may simply allow automatic control of the actuator, to unlock the lock during operation, as will be discussed in more detail below.

As discussed above, actuator 10 includes a housing 20 secured to the outer side of one of the side walls of conduit 16, and rotatably assembles the end portion of output shaft 14 of the damper. Driving the output shaft 14 in a counterclockwise direction, to open the damper 12, is accomplished by relatively low torque, and the selectively excitable electric motor 30, located in the housing 20 as illustrated in Figure 3, to which specific reference is now made. When output shaft 14 is rotated counterclockwise, a torsion spring 32 is loaded, or wound, and serves to rotate shaft 14 clockwise to close damper 12 when motor 30 is turned off. The location of spring 32 within the gear train not only optimizes the torque multiplication of the spring force to return the shock to its zero or safety condition, but also greatly reduces the torque required to apply the load. previous manual.

The motor 30 includes a driveshaft 34 and, as mentioned above, this has a relatively low torque. The motor drive shaft 34 is connected to the output coupling 26, via a drive gear train, or gear train 36, which causes the output coupling 26 to rotate at a substantially slower speed than the drive shaft 34 of the motor. engine, and is capable of exerting a substantially greater torque than the drive shaft 34 of the engine. In this case, gear train 36 includes four gears and pinions 3844, in transmission relationship with each other to multiply the torque from the engine, while substantially reducing the speed at which the output coupling 26 is driven. also includes

ES 2 269 846 T3 a small thrust washer 46 and an output bearing 48, relative to the output coupling 26. The drive gear train in its assembled form is illustrated in Figure 4, and the relationship is shown more clearly between the individual gears.

To explain the operation of the actuator 10 described thus far, it is assumed that the damper 12 is in its closed or zero position, and that the drive to the motor 30 has been removed. Let us now assume that a control signal from the control four 50, causes motor 30 to be energized, to effect rotation of motor drive shaft 34. Such shaft acts through gear train 36 to rotate output coupling 26 to rock damper 12 toward its open position and, in turn, to wind torsion spring 32. Damper opens to which reaches its fully open position, at which point the motor remains energized, but goes into a clamping condition. In this way, the damper is held in its fully open position by the motor, against the force of spring 32.

Now assume that motor 30 is no longer energized, either by a control signal from control panel 50, or by loss of electrical power. Upon deactivation of the motor 30, the torsion spring 32 unwinds, and rotates the output coupling 26 in the reverse direction, to place the damper 12 in a known safety state. In the illustrated embodiment, torsion spring 32 works to close damper 12. When the damper is fully closed and strikes the stop 18 (see Figure 1) in its zero position, the spring continues to apply the force of the preload, through the gear train 36, ensuring that a pressure continues to be applied. positive closing force on damper 12.

As discussed above, the application of spring preload 32 is accomplished via manual correction interface 22. It should be noted that this manual correction can also be used to manually position, or open, the damper in the case of a shock. loss of power, in order to facilitate maintenance or repair of the shock absorber. In either case, if manual correction is used to impart a pre-loading force to spring 32, or to manually position, or open, the damper, the normal functionality of spring 32 and gear train 36, they want to return to the damper to its zero position, it can be locked via locking mechanism 52.

The locking mechanism 52 also works in conjunction with the gear train 36, to prevent the spring 32 from returning the damper or its zero position. As can be seen more clearly from FIG. 3, the lock mechanism 52 includes the lock reset element 54, a stop pin 56, and a lock reset spring 58. As shown in Figure 4, the locking mechanism 52 works in conjunction with the gear train at a certain time, so that the applied braking force is multiplied through the gear train, to prevent rotation of the output coupling. 26. Preferably, the location of the locking mechanism is upstream of interface 60, between gear train and spring 32, a position of higher speed and lower torque rotation.

The operation of the locking mechanism 52 can be better understood through an examination of Figures 5 and 6. In Figure 5 the locking mechanism 52 is illustrated in its unlocked, quiescent position. In this position, the lock reset spring 58 applies a force on the spring receiver 62. This force biases the gear segment head 64 in a clockwise direction so that it is rotated until the stop pin 56 contacts. with the end of the groove 66. The face of the gear segment head 64 includes a toothed portion 68 and a smooth portion 70. In another embodiment, the toothed portion 68 occupies approximately 25 °, although this can be varied based on the tooth pattern, and the spacing of the gears. 40 mating with toothed portion 68. That is, a number of teeth may be provided, sufficient to hold the gear against the force applied by spring 32. In the unlocked position illustrated in FIG. 5, lock reset spring 58 maintains smooth portion 70 in association with gear 40 so that gear 40 can rotate freely in either direction. In the illustrated embodiment, the rotation of the gear 40 in a clockwise direction is relative to the opening of the damper 12, which rotation of the gear 40, in a clockwise direction, closes the damper 12. It is noted that such clockwise rotation of the gear 40 is the result of the action of the spring 32 to close the damper, after a loss of power.

In FIG. 6, the locking mechanism 52 is illustrated in its closed position. In this closed position, rotation of gear 40 clockwise is prevented by stop pin 56, which has come into contact with the end of slot 66. This locked position is maintained by the force of spring 32 acting through the gear train, against the force of lock reset spring 58, which is biased to rotate toothed portion 68 of gear segment head 64, disengaging it from gear 40. Since gear 40 is prevented from continuing clockwise rotation under the force of spring 32, this blocks the remainder of gear train 36, and the rotation of output coupling 26. Thus, damper 12 is prevented from closing under the force of spring 32. In the initial installation of the actuator 10, this output coupling lock is used once a preload has been manually added to the spring 32, via the interface 22 shown in FIG. 2. Once the preload has been applied, and output coupling 26 locked, output shaft 14 of damper 12 is coupled to output coupling 2610, with the damper positioned in its zero position, as discussed above in relation to figure 1.

Once locking mechanism 52 has been engaged, it can be manually disengaged, by using tool 24 to rotate interface 22 in the direction to wind spring 32. In the illustrated embodiment, the user needs to rotate interface 22, by an amount sufficient to rotate gear 40 approximately a minimum of 10 °, to disengage the lock. Once this occurs, the lock reset spring 58 will bias the gear segment head, clockwise until the stop pin 56 contacts the end of the slot 66, as illustrated in Figure 5. A Once the gear mechanism 52 is disengaged, the

ES 2 269 846 T3 gear train 36 is free to rotate in any direction, to the effect of opening the damper 12 under the control of the motor 30, and to the effect of closing the damper 12 under the control of the spring.

Alternatively, the locking mechanism 52 can be disengaged automatically, under the control of the control panel 50 and the motor 30. That is, if the control panel wishes to unlock the locking mechanism 52, or wishes to order a closure of the damper 12, it controls the motor 30 to actuate in an activation direction, that is, it drives the output shaft in a direction to open the damper, just enough to ensure that gear 40 rotates counterclockwise enough to disengage tooth portion 68 from gear segment head 64. As discussed above, once toothed portion 68 disengages gear 40, lock reset spring 58 will bias lock mechanism 52 toward its unlocked position. Since the position of the locking mechanism 52, relative to the gear train 36, is closer to the motor, and thus closer to the high speed, low torque portion of the gear train 36, this slight rotation of the gear train 36, sufficient to unlock locking mechanism 52, does not impart any significant movement to the damper. Indeed, even if damper 12 were in its fully open position when locking mechanism 52 was engaged, motor 30 would be able to unlock locking mechanism 52.

The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive, nor to limit the invention to the specific embodiments disclosed. In light of the above teachings, numerous modifications or variations are possible. The discussed embodiments have been chosen and described, to provide the best illustration of the principles of the invention and their practical application, to thereby enable a person of ordinary skill in the art, to use the invention in various embodiments, and with various modifications, which are suitable for the specific use contemplated. Undoubtedly, while the above description has used a spring return actuator, to illustrate the features of the invention, a person skilled in the art will recognize that manual correction and the locking mechanism are equally applicable to return actuators that do not be spring. In such an application, manual correction is used to manually position the damper, rather than winding a spring. All such variations and modifications are within the scope of the invention, as determined by the appended claims, when they are interpreted in accordance with the breadth that corresponds to it fairly, legally, and equitably.