BACKGROUND OF THE INVENTION
1. Field of the Invention
Various embodiments of the present invention described herein generally relate to children's entertainment devices and, in particular, to a drive system for a children's entertainment device that imparts rotational motion to an entertaining element.
2. Description of Related Art
Many children's entertainment devices incorporate a motor-driven rotating element configured to automatically and continuously rotate in order to entertain children. For example, motorized children's mobiles typically include a support structure configured to suspend a rotating element above a child support surface, such as a crib. The rotating element may comprise various visual stimuli, such as figurines and other decorative objects. Typically, the rotating element is powered by a motor configured to continuously rotate the rotating element and its visual stimuli in order to entertain a child.
Existing children's mobiles often rely on brushed DC motors in order to power such rotating elements. These brushed DC motors, however, are relatively large and heavy, and typically require a gearbox in order to reduce the output speed of the motor. Furthermore, such motors are commonly noisy in operation, have high battery consumption, and tend to fail after a relatively low number of operating hours. Accordingly, there is a need in the art for a smaller, quieter, more reliable, and more energy efficient drive system for driving a rotating component of a children's entertainment device.
BRIEF SUMMARY OF THE INVENTION
Various embodiments of the present invention are directed to a children's entertainment device comprising at least one support member, a rotatable entertaining element suspended from the at least one support member, and a drive system configured to impart rotational motion to the entertaining element. The drive system comprises a stepper motor configured for rotating a drive member in a stepped rotational motion, and a damper operatively connected between the drive member and the entertaining element. The damper is configured for at least partially damping the stepped rotational motion generated by the stepper motor and for rotating the entertaining element. In certain embodiments, the stepper motor is configured for rotating the drive member in incremental steps at a frequency that causes the entertaining element to rotate continuously. In further embodiments, the stepper motor is configured for rotating the drive member in incremental steps at a frequency that causes the entertaining element to rotate with a substantially constant angular velocity.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
FIG. 1 shows a perspective view of a children's entertainment mobile according to one embodiment of the present invention;
FIG. 2 shows an exploded view of a drive system for a children's entertainment mobile according to one embodiment of the present invention;
FIG. 3 shows a cutaway side view of the drive system of FIG. 2 according to one embodiment of the present invention;
FIG. 4 shows a drive shaft according to one embodiment of the present invention;
FIG. 5 shows a mating member according to one embodiment of the present invention; and
FIG. 6 shows a graph indicating the rotation of a stepper motor and an entertaining element according to one embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
Various embodiments of the present invention are directed to a children's entertainment device having a stepper motor drive system configured to drive a rotatable entertaining element. The stepper motor consumes less power than a typical electric motor (e.g., a brushed DC motor) due to its low duty cycle, and is generally smaller and lighter than a typical brushed DC motors. However, stepper motors output rotational motion in intermittent rotational steps, which can result in a jerky motion if applied directly to the entertaining element.
Accordingly, in various embodiments of the present invention, a damper is provided between the stepper motor's drive shaft and the entertaining element in order to at least partially damp the intermittent rotational motion output by the stepper motor. In this way, the stepper motor is able to smoothly and continuously rotate the entertaining element. As will be appreciated from the description herein, various embodiments of the stepper motor drive system may be incorporated into a variety of children's entertainment devices, such as rotating crib mobiles and entertainment devices attached to jumpers, bouncers, strollers, play yards, and the like.
Children's Entertainment Mobile
FIG. 1 illustrates a children's entertainment mobile 5 according to one embodiment of the present invention. As shown in FIG. 1, the mobile 5 is generally comprised of a base 20, support arm 30, and an entertaining element 40. According to various embodiments, base 20 is generally configured for supporting the support arm 30 and entertaining element 40, and may include an attachment device configured for securing the base 20 to the railing of a children's crib, such as that described in U.S. application Ser. No. 13/224,161, which is incorporated herein by reference. The support arm 30 is generally configured to act as a support member for the entertaining element 40 and support for a drive system configured for rotating the entertaining element. As shown in FIG. 1, the support arm 30 is affixed to an upper portion of the base 20 and extends upwardly and outwardly in order to suspend the entertaining element 40 above a children's support surface, such as the floor of a crib.
In the illustrated embodiment of FIG. 1, the entertaining element 40 is a children's mobile comprised of a conical canopy 44 suspended from an upper support member 42 by a plurality of strings 46. In addition, the entertaining element 40 includes a plurality of figurines 48 suspended from the conical canopy 44. As described in greater detail herein, the entertaining element 40 is removably secured to a drive system positioned predominately within a housing 32 at the upper end of the support arm 30. The drive system is configured to automatically rotate the entertaining element 40—and thereby its canopy 44 and Figurines 48—in order to entertain a child (e.g., a child positioned in a crib to which the base 20 is attached). The entertaining element can take many different forms based on design preferences, and may include multiple moving or stationary elements.
FIG. 2 shows an exploded view of various components of a drive system 10 configured for automatically rotating the mobile's entertaining element 40 according to one embodiment. In the illustrated embodiment, the drive system 10 comprises a stepper motor 110, a drive shaft 120, a compression spring 130, a retaining plate 140, a mating member 150, and a damping member 160. As noted above, the drive system 10 is positioned predominately within a housing 32 at the upper end of the mobile's support arm 30. As shown in FIG. 2, the housing 32 includes an upper housing member 102 and a lower housing member 104, which may be joined together to form an enclosure in which the drive system 10 predominately resides.
FIG. 3 shows a cutaway view of the drive system 10 assembled within the housing 32 and connected to the entertaining element's upper support member 42. As shown in FIG. 3, the stepper motor 110 is secured to an interior portion of the upper housing member 102 (e.g., by screws, clips, or other attachment devices). According to various embodiments, the stepper motor 110 can be a unipolar or bipolar stepper motor, and can be configured for rotating clockwise, counterclockwise, or both. In addition, the stepper motor 110 can be configured to change directions in order to provide reciprocating swinging motion. The stepper motor 110 can be powered by any suitable power source (e.g., batteries, a connection to an AC power outlet). In the illustrated embodiment, the stepper motor 110 is configured for rotating an output shaft 112 in intermittent rotational steps. According to various embodiments, the output shaft 112 acts as a drive member outputting the rotation generated by the stepper motor 110. For example, in one embodiment, the drive system 10 includes an integrated circuit configured to control the stepper motor 110 such that the output shaft 112 rotates clockwise 7.5 degrees every 417 milliseconds (i.e., 48 “steps” per revolution at a speed of three revolutions per minute). However, as will be appreciated from the description herein, the speed and step range of the stepper motor 110 may be adjusted according to user preferences.
As shown in FIG. 3, the stepper motor's output shaft 112 is connected to the drive shaft 120. FIG. 4 shows a perspective view of the drive shaft 120 according to one embodiment. As shown in FIG. 4, the drive shaft 120 comprises an elongated cylindrical body 122 defining a central cavity 124. As can be seen in FIG. 3, the drive shaft's central cavity 124 extends longitudinally into the drive shaft 120. The drive shaft 120 also includes a circular flange 126, which extends outwardly around a medial portion of the drive shaft's body 122. In addition, the drive shaft 120 includes an engagement ball 125, which is positioned at the lower end of the drive shaft's body 122 and has a hexagonal cross section.
Referring back to FIG. 3, the stepper motor's output shaft 112 is positioned within the drive shaft's central cavity 124 and affixed to the drive shaft 120 such that the drive shaft 120 cannot be moved with respect to the output shaft 112. In other words, the drive shaft 120 rotates with the output shaft 112 such that both components rotate simultaneously in the same increments and at the same angular speed. As a result, the rotation of the drive shaft 120 is synchronous with the output shaft 112. As will be appreciated from the description herein, however, the drive shaft 120 may be connected to the output shaft 112 using various attachment mechanisms or methods according to various embodiments.
As shown in FIG. 3, drive shaft 120 is connected to the mating member 150. FIG. 5 shows a perspective view of the mating member 150 according to one embodiment. As shown in FIG. 5, the mating member 150 comprises an upper plate 151 and an elongated body 152 extending downwardly from the upper plate 151. The upper plate 151 defines a pair of shoulders 153, which extend outwardly past the elongated body 152. The mating member's elongated body 152 defines a hexagonal cavity 154, which extends longitudinally into the center of the body 152 and has a hexagonal cross-section. In addition, the elongated body 152 defines a side opening 156 in communication with the mating member's cavity 154, and a slot 157 which extends through the bottom end of the mating member's body 152 and is in communication with the side opening 156 and cavity 154.
Referring back to FIG. 3, the drive shaft's ball 125 is positioned within the mating member's hexagonal cavity 154. In particular, the cross-section of the hexagonal cavity 154 is configured to mate with the ball 125, which has a similarly dimensioned and slightly smaller hexagonal cross section. The interface between the drive shaft's ball 125 and the hexagonal cavity 154 permits the mating member 150 to move vertically with respect to the drive shaft 120, but substantially constrains the mating member 150 from translating laterally or rotating about its longitudinal axis with respect to the drive shaft 120. In other words, the mating member 150 rotates with the drive shaft 120 such that both components rotate simultaneously in the same increments and at the same angular speed. As a result, the mating member 150 is operatively connected to the stepper motor's output shaft 112 and the rotation of the mating member 150 is synchronous with both the drive shaft 120 and the output shaft 112. In the illustrated embodiment of FIG. 3, the interface between ball 125 and cavity 154 allows for some movement of the longitudinal axis of the mating member 150 such that the mating member 150 and drive shaft 120 can be axially misaligned. In other embodiments, the mating member 150 may be configured such that it cannot be axially misaligned from the drive shaft 120. In addition, as will be appreciated from the description herein, the cross-sections of the ball 125 and cavity 154 may comprise other shapes and achieve the same effect. In addition, the ball 125 and cavity 154 may be connected using other mechanisms or methods to provide the same functional result.
As shown in FIG. 3, the vertical movement of the mating member 150 is influenced by the compression spring 130. In particular, the compression spring 130 is positioned around the cylindrical body 122 of the drive shaft 120 such that the spring's lower end engages the upper surface of the drive shaft's circular flange 126. The spring's upper end is connected to the retaining plate 140 proximate a central hole in the retaining plate 140. The retaining plate 140 is connected to the shoulders 153 of the mating member 150 (e.g., by screws), thereby causing the mating member 150 and retaining plate 140 to move vertically together. In addition, as will be appreciated from FIG. 3, the output shaft 112, drive shaft 120, mating member 150, retaining plate 140, and spring 130 all rotate synchronously together.
As shown in FIG. 3, the mating member's elongated body 152 extends through a hole 106 in the lower housing member 104. The compression spring 130 is biased such that, under normal loading (e.g., the weight of entertaining element 40), the mating member 150 and retaining plate 140 are positioned at the height shown in FIG. 3. However, when the mating member 150 is subjected to excessive loading (e.g., a child or user pulling down on the entertaining element 40), the spring 130 compresses and permits the mating member 150 and retaining plate 140 to move downwardly. In the illustrated embodiment, the drive system 10 is configured such that the mating member 150 does not contact the lower housing member 104 in either its normally-biased upper position or its loaded lower position. This configuration reduces the friction applied to the stepper motor 110 and increases the overall efficiency of the drive system 10.
According to various embodiments, the damping member 160 is configured for being removably secured to the mating member 150. As shown in the illustrated embodiment of FIG. 2, the damping member 160 includes an attachment member 162 affixed to the damping member's upper end. As shown in FIG. 3, the damping member 160 is configured such that its attachment member 162 can be inserted through the side opening 156 and into the bottom of the cavity 154. When the attachment member 162 is positioned in the bottom of the cavity 154, the damping member 160 extends downwardly from the attachment member 162, through the slot 157, and downwardly from the bottom of the mating member 150.
According to various embodiments, the attachment member 162 is configured to engage the mating member 150 such that the attachment member 162 is secured to the mating member 150 and resistant to rotating with respect to the mating member 150. In certain embodiments, the attachment member 162 may configured such that the weight of the entertaining element 40 holds the attachment member 162 in place. In other embodiments, engagement features (e.g., teeth, ribs, rubber surface) may be provided on the portions of the attachment member 162 and cavity 154 in contact with one another in order to hold the attachment member 162 in place. In the illustrated embodiment of FIGS. 2 and 3, the attachment member 162 comprises a rigid body shaped to resemble the lower half of a sphere. However, according to various other embodiments, the attachment member 162 may comprise any other suitable member, such as a knot at the top of the damping member 160 or a small ball attached to the top of the damping member 160.
As shown in FIG. 3, the damping member 160 is connected to the entertaining element's upper support member 42. Accordingly, when the attachment member 162 is engaged with the mating member 150, the entertaining element 40 is operatively connected to the stepper motor 110 via the damping member 160, the mating member 150, the drive shaft 120, and the output shaft 112. In other embodiments, the damping member 160 may be affixed to the mating member 150, and the entertaining element's upper support member 42 may be removably secured to the damping member 160 itself.
As noted above, the damping member 160 is configured to act as a damper to dampen the rotational motion imparted by the stepper motor 110 to the entertaining element 40. In the illustrated embodiment, the damping member 160 comprises a braided nylon cord configured to twist in response to being rotated by the stepper motor 110. For example, in one embodiment, the stepper motor 110 may be configured to rotate its output shaft 112 in incremental 7.5 degree steps. When the stepper motor 110 is pulsed by its power source and rotated through one step (e.g., rotated 7.5 degrees), the output shaft 112—and thereby the drive shaft 120, mating member 150, and attachment member 162—rotate quickly through the step angle and then stop. As the damping member 160 is flexible, it twists in response to its attachment member 162 being rotated by the stepper motor 110. This twisting action briefly stores the rotational kinetic energy transmitted to the damping member 160 by the stepper motor 110. When the damping member 160 begins to unwind, it releases the stored kinetic energy and applies a torque to the entertaining element's upper support member 42 that causes the entertaining element 40 to rotate. However, as will be appreciated from the description above, the rotational motion of the entertaining element 40 imparted by the damping member 160 is at least partially dampened and lags behind the rotation of the stepper motor 110. In other words, the rotation of the entertaining element 40 is not synchronous with the rotation of the stepper motor's output shaft 112 as the entertaining element does not rotate in the same intermittent steps of the stepper motor's output shaft 112. As a result, the stepper motor 110 is able to drive the entertaining element 40 such that it rotates smoothly.
In certain embodiments, an integrated circuit controlling the stepper motor 110 can be configured to repeatedly pulse the stepper motor 110 at a frequency that causes the entertaining element 40 to rotate continuously. For example, FIG. 6 shows a graph indicating the rotation of the stepper motor 110 and the entertaining element 40 when the stepper motor 110 is rotates its output shaft 112 in 7.5 degree steps at three revolutions per minute (i.e., 48 steps per revolution, with steps occurring every 417 milliseconds). As is evident from FIG. 6, the frequency of the output shaft's rotation is such that, before the damping member 160 stops applying torque to the entertaining element 40 in response to being twisted by a single step, the output shaft 112 rotates through another step and twists the damping member 160 again. As a result, the damping member 160 dampens the intermittent stepping rotation of the output shaft 112, applies torque to the entertaining element 40 substantially constantly, and causes the entertaining element 40 to rotate smoothly and consistently. In particular, in certain embodiments, the stepper motor 110 may be configured to drive the entertaining element 40 such that it rotates continuously with a substantially constant angular velocity. In other embodiments, the stepper 110 may be configured to drive the entertaining element 40 such that it rotates with a discontinuous, varying angular velocity, which may be more interesting to a child. In addition, the stepper motor 110 can achieve comparatively low battery consumption due to its low duty cycle (e.g., 3 to 10 times longer battery life than a brushed DC motor).
As will be appreciated from the description herein, the damping member 160 may be comprised of any deformable material capable of damping the rotational motion imparted by the stepper motor 110. For example, in various other embodiments, the damping member 160 may comprise a rubber band, a spring, a cord, a thin wire, a fabric member, or various other flexible materials capable of storing and releasing rotational kinetic energy. In addition, the stepper motor 110 can be configured to rotate in steps at any one of a range of degrees (e.g., a relatively small step being 0.5 degrees and a large step being a full 360 degree rotation). Furthermore, the rotational speed of the entertaining element 40 is based on the pulse rate (e.g., the number of times the motor steps in a given time period) and the step period (e.g., the time it takes the stepper motor 110 to rotate one step) of the stepper motor 110. Accordingly, the rotational speed of the entertaining element 40 is widely variable (e.g., zero RPM to 30 RPM). For example, a high RPM may be achieved by pulsing the stepper motor 110 at the same interval as the step period. In addition, in certain embodiments, an integrated circuit may be configured for tracking the position of the output shaft 112 (e.g., by counting steps in order determine position) in order to more precisely control the stepper motor 110.
In various embodiments, the above described variables in the operation of the stepper motor 110 can be controlled by one or more user input controls provided on the mobile 5. Such user controls may include, but are not limited to, an on/off switch, a timer for rotating the entertaining element 40, a speed dial for adjusting the speed of the entertaining element's rotation, and a direction dial for changing the direction of the entertaining element's rotation. As will be appreciated from the description herein, these various user controls may be in communication with an integrated circuit programmed to control the operation of the stepper motor 110.
Furthermore, as will be appreciated from the description herein, various changes and modifications to the above-described components may be incorporated in various other embodiments of the children's entertainment mobile 5. For example, in certain embodiments, the drive system's compression spring 130 may be located elsewhere in the drive system 10 or may be comprised of multiple springs. In addition, the compression spring 130 may be replaced by another device, such as an air spring or hydraulic component. In addition, various embodiments of the drive system 10 may not include a spring and may be configured such that the mating member 150 and retaining member 140 are vertically constrained. In such embodiments, the mating member 150 and drive shaft 120 may comprise a single drive shaft component directly affixed to the stepper motor 110 and configured to be secured to the damping member 160.
According to various embodiments, the orientation of the location of the various components of the drive system 10 may also be adjusted. For example, the stepper motor 110 may be positioned such that its output shaft is vertically upright, vertically upside down, or horizontal, and may be connected to a variety of gears and other drive shafts to generate rotational motion analogous to that described herein. As another example, the stepper motor 110 may be positioned in the base 20 and connected to a drive shaft in the housing 32. In addition, various embodiments of the stepper motor drive system 10 described herein may be incorporated into various other children's entertainment devices (e.g., rotating elements positioned on play gyms, toy bars, or other hanging toys, and elements configured to swing along a reciprocating path) and is not limited to use in children's mobiles.
CONCLUSION
Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Patent Application
20120100776
